Transcript for:
Anatomy and Physiology Overview

hello and welcome back to anatomy and physiology part two of the emergency care in the streets lecture now last uh recording we left off with the muscular skeletal system and now we're gonna pick up with the nervous system okay so let's get started okay the nervous system perhaps the most complex organ in the body the components are the brain spinal cord and thousands of nerves and those nerves allow every part of the body to communicate it's responsible for the found fundamental functions such as breathing pulse rate and blood pressure and it allows for higher level functions such as reading a book enjoying music or having a discussion so the main functions are to monitor the internal and external environments integration of the sensory information and coordination of voluntary and involuntary responses it's divided into the central nervous system which is the cns or the peripheral nervous system which is the pns so the cns is responsible for thought perception feeling and the autonomic body functions and the pns is the somatic nervous system and the autonomic nervous system now the somatic nervous system is the part of the peripheral nervous system that regulates activities over which there is voluntary control so you could pick stuff up and put stuff down that's the somatic now the autonomic nervous system it controls the body functions that occur without voluntary control so involuntary the figure shows the organization of the nervous system neuro tissue is the responsible for the conduction of electrical impulses between the brain and the rest of the body it contains two basic types of cells you have the neuroglia and the neurons the neuroglia provides a supporting skeleton for neural tissue it isolates and protects the cell membrane of the neurons there's types of neuroglia cells and they include astrocytes and those are found in the central nervous system the most numerous type of neuroglia then you have microglia cells all of geosites and satellite sites swan cells so multiple different types neurons are nerve cells they are the fundamental element of the nervous system present throughout the body they are groups of nerve cells are bundled together to form nerve fibers and groups of nerve fibers are bundled together to form a nerve which is the tissue that connects the nervous system with body parts of organs neurons are supplied with oxygen and nutrients from the nerve's blood vessels and nerves are information highways impulses that travel to and from the brain so there are three basic parts of the neuron you have the dendrite the cell body and the axon the axon that's the impulse exits the neuron through the axon an axon is a projection that sends the signal from the cell body to the target tissue or other neurons so neurons may have dozens of dendrites but usually only one axon okay so let's talk about axons they may or may not be wrapped in myelin in myelin myelinated axons form the white matter in the brain the brain stem and spinal cord myelin allows the cells to transmit it signals continuously and increases the speed of conduction there are gaps between the myelated regions and they are called nodes of ranvir axons without myelin shields are termed gray matter because these axons lack the myelin sheath impulses travel slower than they would in the white matter so an axon terminal is the portion of the axon where the neurotransmitters are manufactured nerve cells are classified by the direction in which they transmit the impulses so you have the afferent which are sensory nerves impulses from the sensory receptors in the internal organs and skin to the brain and the spinal cord and then you have the efferents which are motor nerve and they carry impulses from the cns to the organs muscles and glands then you have the interneurons and they carry impulses from sensor neurons to motor neurons so synapsis and synaptic transmission dendrites and axons of adjacent nerve cells are supported by a small gap called the synapse a synapse is made up of three main parts you have the pre-synaptic plasma membrane synaptic clef and the postsynaptic plasma membrane there are two types of synapse and they're chemically or electrical most neurons use neurotransmitters to transmit their signal across the synapse to other neurons or to muscle or gland cells at the end of the axon is a presynaptic neuron or tiny bulges called synaptic knobs or synaptic terminals neurotransmitters diffuse across the synaptic cleft two receptor sites on the postsynaptic plasma membrane to which they release neurotransmitters bind so the released neurotransmitters may either be excitatory or inhibitory right so as a paramedic you may administer a variety of medicines to enhance slow or even stop these neurotransmissions transmissions of nervous impulses is what we're going to talk about next so when the cell is at its resting potential greater contractions of extracellular sodium and intracellular potassium are available they're also in the cell and it's a negative negatively charged ion chloride depolarization of the nerve cell results from opening of the sodium channels and the influx of sodium into the cell this influx creates a positive charge causing an action potential inside the cell this process creates a wave of depolarization along the nerve fiber as each cell depolarizes when stimulated by the previous neuron repolarization occurs as potassium leaves the cell and is completed when the sodium potassium pump restores sodium and potassium to the original positions as the wave of depolarization continues it eventually reaches the end of the nerve fiber at the synaptic clef the n may be the junction of the axon and dendrite of another neuron or the neuromuscular junction where the nerve impulse stimulates muscular contraction okay so let's talk about the central nervous system next remember you have the central nervous system and the peripheral nervous system those are the two main systems in the nervous system and the cns is responsible for the integration and coordination of sensory information and motor responses because the structures of the cms cns can be easily damaged with devastating results the body has four protective mechanisms it has the bone meninges csf and a brain blood barrier the brain has the additional protective layer called the scalp the scalp consists of the following layers so you have the hair you have subcutaneous tissue and you also have loose connective tissue and then you have the periosteum that's the dense fibrous membrane covering the surface of the bones you have bone and the bone provides physical protection for the cns and you have the meninges so they form a covering over the brain and spinal cord dura mater is the outer toughest membrane arachnoid that's the second layer pia mater is the innermost layer and they float in csf now csf is manufactured by specialized cells within the chord plexus in the ventricles and flows into that subarachnoid space between the pia mater and the arachnoid membrane you also have a blood brain barrier and that forms a barrier within the brain capillaries and extracellular fluid in brain tissue and then there's your brain it's the primary organ of the nervous system it's the control center for nearly all functions of the body there are four main areas you have this cerebrum and that's the gray matter the disease and that is composed of several structures including the thalamus hypothalamus and subthalamus then you have the brain stem and that's the controlling center for many essential functions the body requires to survive and then you have the cerebellum that's located under the cerebrum and it coordinates various activities including fine and gross muscle coordination let's talk a little bit about body temperature thermoregulation is the process of maintaining homeostasis of temperature the body's average temperature is actually maintained through a balance of gains and losses the body also has means for releasing heat the acceptance average body temperature is 37 degrees celsius or 98.6 fahrenheit body temperature regulation begins in the hypothalamus which acts as a thermostat activating mechanisms for increasing or decreasing temperature the figure on this slide shows the body's mechanism mechanisms for maintaining body temperature okay so the limbic system is composed of several structures beneath the cerebral cortex with connections to other parts of the brain including the thymus hypothymus and the frontal and temporal lobes of the cerebrum the emotional brain or the feeling and reacting brain it's involved in generation integration and control of emotions and connecting them with behavioral responses motivation learning and transmission of information from short to long-term memory and functions necessary for self-preservation including response to emotional stimuli then you have the spinal cord it's part of the cns that connects the brain to skeletal muscle tissue and skin to other structures by means of spinal nerves it exits the skull through the forum magnum and extends through the spinal column the spinal cord is encased within the cerebral canal down to the level of the second lumbar vertebra in most adults nerve fibers are arranged in specific bundles within the spinal cord to carry the messages from one specific area of the body to the brain and back okay so we've talked about the central nervous system now let's move into the peripheral nervous system it's responsible for communication between the cns and the rest of the body there are two divisions there's the somatic nervous system it controls voluntary muscles and then there's the visceral or the autonomic nervous system and that controls involuntary and that is further divided into the sympathetic and the parasympathetic nervous systems you have spinal nerves there are 31 pairs of nerves arising bilaterally from between the vertebrae and the spine each sending and receiving sensory and motor messages to and from the cns from a portion of the body you also have nerve plexus and that's the spinal cord it combines in five areas of the body to form networks and these are called plexus where spinal nerve roots come together and transmit their impulses to areas of the body through a common nerve this allows several spinal nerves to control one area of a body you have five main plexus in the body and they're the cervical brachial lumbar sacral and the coccygeal plexus then you have cranial nerves there are 12 pairs they arise from the base of the brain all but two of them are exit the main of the brain stem and so the two that don't are the effect of factory nerve and the optic nerves cranial nerves are either referred to by their name or abbreviated as cn12 and so forth the number reflects the order in which they connect to the brain from anterior to posterior so the figure on this slide shows the 12 cranial nerves and you can see the names and the numbers the autonomic nervous system is part of the pms that is not under voluntary control there are two divisions remember in the autonomic nervous system it's the sympathetic and that mobilizes the body for activity such as the fight or flight and then there's the parasympathetic it's responsible for conserving energy and maintaining organ function counter balancing the sympathetic division so it's almost it's the rest and digest system figure shows the division of the autonomic nervous system okay so sensory function sensation is an awareness of body state or condition that results from stimulating stimulation of sensory receptors that respond to specific internal and external stimuli through sensation the pns is able to collect and relay information about the body and its external environment sensation is generated and transmitted by thousands of sensory receptors that monitor conditions inside and outside of the body the messages are generated and transmitted by sensory receptors message is processed and brought to a conscious thought it generates an autonomic response or reflex or is discarded as unimportant genera general senses are the means by which the body gathers information from its environment sensations such as pain or temperature touch or pressure are monitored throughout the body by receptors in different tissues you have the somatic and that provides sensory information about the environment and the body and then you have visceral that supply information about the body's internal organs pain receptors are sensitive to mechanical thermal electrical or chemical stimuli that could damage the body so they monitor pain you have visceral pain and that is deep pain caused by the activation of pain receptors in internal areas of the body that are enclosed within the cavity such as the chest cavity or the abdominal cavity or the pelvis somatic pain is caused by the activation of pain receptors in the body's superficial tissues such as the skin bones muscles and joints referred pain is pain perceived as occurring in one part of the body other than its true source and this frequently occurs with gi issues and then you have phantom pain and it's the sensation of pain in a part of the body that's no longer present so with limb amputation okay you have thermoreceptors and they are nerve endings that respond to heat and you have touch and pressure those monitor the changes in physical properties tactile receptors are touch and pressure receptors that are located on the skin so special senses serve as the body's first line of protection against environmental hazards you have the sense of smell and that's all faction all faction is controlled by the first cranial nerve so also known as cn1 the upper nasal cavity contains the smell receptors or olfactory olfactory cells respond to chemicals dissolved in the mucus covering these cells then you have the taste of the sense of taste that's gestation the taste buds in the mouth allow for the sense of taste taste receptors respond to four primary taste sensations and that's sweet salty sour and bitter okay now we're going to talk about the sense of sight it's conducted by the second cranial nerve or cn2 the sense of sight is facilitated by the eyes accessory structures the optic nerve and the tracks that conduct the impulses to the brain the eye has two major components and that's the optic part and it gathers and focuses light and to form the image then you have the neural part and that's the retina to convert the optic image to the neural code the eye distinguishes two aspects of light brightness and wavelength the eyeball or globe is the source of the information the brain processes into pictures okay the globe is hollow and divided into the anterior cavity and posterior cavity the globe is controlled and directed by six intrinsic muscles light passes into the globe's refractoring system which is responsible for um focusing the image onto the specialized nerve endings of the eye okay the image focuses on the retina is an upside down image and it's a miniature version of the environment in front of the eye so your sense of hearing the organs of hearing are divided into three portions you have the external middle and inner ear the external ear conducts sound to the tympanic membrane or eardrum which separates the ear canal from the middle ear the middle ear contains the auditory ossicles or three small and delicate bones that link together to transmit sound waves to the cochlea the middle end of the staples is attached to another membrane the oval window which separates the middle ear from the entrance to the cochlea which encases the primary receptor for sound the bony labyrinth protects structures of the middle ear the cochlea is a bony spiral shell-shaped containing the cochlear duct partial or complete loss of hearing is known as deafness so the sense of balance the vestibular system is contained within the inner ear and composed of a pair of fluid-filled sacs known as office and three more fluid-filled looping passageways known as semicircular channels the structures are used by the cns to collect information about movement and orientation of space semicircular canals use the movement of fluid to sense rotational movement in each of the three planes okay now we're moving right on through to the endocrine system it's made up of glands located throughout the body the glands and hormones throughout the body to maintain homeostasis and it regulates many of the metabolic functions of the body intracellular communication so to maintain homeostasis the body uses many different types of chemical messengers to rely relay information to neighboring or distant cells so let's say some examples of the chemical messengers include neurotransmitters hormones ions growth factors or products of cellular metabolism most chemical messengers act on specific receptors on target cells that once they're activated trigger a series of secondary events that mediate the response of the target cells to the stimulus with endocrine communication glands or specialized cells secrete an endocrine hormone into blood that then circulates throughout the body thereby influencing tissues distant from the site of manufacture another form of intracellular communication is known as the paracrine communication so the paracrine hormones are chemical messengers that are released into circulation by one type of cell and act on a neighboring cell of a different type so an example would be the release of the ach at the neuromuscular junction and then you have hormones hormones are manufactured in endocrine glands they are released directly without ducts into the circulatory system they travel to specific target cells which have receptors that carry out a complex set of instructions and actions when exposed to a specific hormone each target cell that specif has specific receptor sites on the cell membrane or inside the cell to which the specific hormone can attach or bind there are three general classes of hormones and they are proteins or polypeptides amine hormones or steroid hormones hormones operate within the feedback system so it's either a positive or negative to maintain homeostasis negative feedback mechanisms are those in which the desired effect has been achieved so further action is inhibited and then the positive feedback negative are mechanisms in are those in which an effect leads to or causes another effect so examples of a positive would be the clotting cascade in childbirth an example of the negative would be a release of epi from the adrenal medulla in response to stress so you have pgs and those are prosta prostaglandins and they're not hormones but their effects are stimular or similar they are derivatives of an essential fatty acid and are called tissue hormones because their effects are usually located on or near a cell in which they are made of there are 16 different pgs and their effects are of short duration the hypothymus that's a human body regulates itself by communicating with a cellular level through a nervous system and endocrine systems the hypothymus is the main link between the endocrine system and the nervous system it contains cells that function both on nerve cells and as glandular cells information processed by the hypothymus includes among other things it reports to the blood pressure heart rate body temperature and blood glucose then you have the pituitary gland it is referred to as the master gland it secretes growth hormone thyroid stimulating hormones anti-diuretic hormones and oxytoc oxytocin the pituitary gland is divided into two portions you have the anterior pituitary and it has five types of secretion cells and then you have the posterior and that secretes two hormones the adh and oxytocin are synthesized in the hypothymic normal neurons but are stored in the posterior pituitary gland okay so this figure shows the hormone secreted from the pituitary gland then you have the thyroid gland the thyroid gland is a large gland at the base of the neck it affects almost every body organ in the body including the nervous system cardiovascular ngi systems reproductive organs and the skin hair and nails it is critical to normal metabolism the thymus gland is located in the mediastinum just behind the sternum it functions to help the immune system identify and destroy foreign intruders during infancy and early childhood an individual's thymus is large and decreases in size as the person reaches adulthood and then you have the pancreas it's an organ with both endocrine and exocrine functions in the pancreas within each eyelet of langerhan are alpha cells that secrete glucagon beta cells that secrete insulin delta cells that produce somostatin and f cells that produce pancreatic polypeptides insulin and glucagon work play an important role in maintaining a proper blood glucose balance and then you have the adrenal gland so the adrenal cortex produces steroidal hormones called cortisteroids which are essential to life corticosteroids among them these corticosteroids assist in the regulation of blood glucose levels they promote the peripheral use of lipids stimulate the kidneys to reabsorb sodium and exert anti-inflammatory effects during times of stress the hypothymus secretes a hormone that stimulates the anterior pituitary to release acth which causes the adrenal cortex to secrete cortisol okay and then you have the gonads their ovaries in women and testes in men testosterone production by the testes and the major female hormones so you have the anterior pituitary gland directs the actions of the ovaries through fsh and hormones and the ovaries produce the following so estrogen progesterone and testosterone you have the penile gland it's located in the posterior end of the third ventricle of the brain it synthesizes and secretes melatonin a hormone that affects sleep wake patterns and seasonal functions all right now we're moving into the circulatory system it consists of the heart and a complex arrangement of connected tubules if there are two circuits in the body you have the systemic circulation and that's when travels throughout the body and then you have the pulmonary circulation and that travels between the heart and lungs the figure shows the circulatory all right you have blood um and basically that's the process of the blood cell formation blood components and organs involved in the development of production you have bone marrow and that's the primary site and then you have lymphoid tissues and that's consisting of the thymus lymph nodes and spleen okay and then you have the spleen that filters and breaks down red blood cells it assists with production of lymphocytes and has an important role in homeostasis and infection control there are functions of the blood if you have a respiratory function that transports oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs you have nutritional aspect and that carries nutrients you have the excretory and that is when they ferry the waste products of the metabolism from the cells where they're produced and then excreted you have the regulatory it transmits hormones to the target organs and then the defensive and that carries defensive cells and antibodies and it protects the body against foreign organisms blood composition so the blood is primarily composed of about 55 plasma and formed cellular fragments of about 45 percent plasma is the liquid portion of the blood in which the formed elements of blood are suspended the form elements are a mixture of red blood cells white blood cells and platelets okay and then you have plasma it's 92 percent water and 7 proteins and the remainder are as oxygen carbon dioxide nitrogen electrolytes and what nutrients and waste red blood cells and these are the guys that carry the oxygen to the tissue there are numerous they contain hemoglobin which is the protein which carries the oxygen by binding to it and they're consistently being made of new ones their lifespans are about 120 days so common laboratory tests on blood are the red blood cell count and that's measured it measures the number of red blood cells in a sample of blood also hemoglobin levels that identifies the amount of hemoglobin found within the red blood cells and then the hematocrit and that gives the overall proportion of red blood cells in the in the blood so it's um the patient's blood is considered balanced if the hemoglobin level is one-third of the hematocrit value the white blood cells they move through capillary walls into the tissues with right blood cells you're going to have an elevated count during an inflammatory response or an immune response or both okay so with platelets they are the key component in the formation of clots or coagulation the production is is controlled by a protein hormone and platelets circulate in the blood for about seven to ten days platelets and blood clotting so clotting is a chain reaction stimulated by the release of a chemical called thromboplastin from injured cells lining damaged blood vessels thromboplastin causes an inactive plasma enzyme to be converted into its active form then that's thrombin this figure shows the clotting cascade it's also called the coagulation cascade all right so blood groups red blood cells contain antigens on their surface within the plasma are antibodies which react with antigens to ensure capability and prevent medical complications people are classified as having one of four blood types based on the presence and absence of those specific antigens and so the system identifies blood types of o a b and a b type o is the universal donor type a b is the universal recipient the rh factor is present in our h negative positive blood and our h factor is not present in rh negative blood and then you have the heart so that's the driving force behind the cardiovascular system it's the pump it sits in the chest above the diaphragm behind and slightly to the left of the lower sternum not much larger than the person's fists and weighs about 9 ounces it circulates 7 000 liters to 9 000 liters of blood daily you have large vessels and those vessels return venous blood from the upper and lower parts of the body to the right atrium and that is the superior vena cava and the inferior vena cava and then you have vessels that carry blood away from the heart the main ones the aorta and then you have the pulmonary arteries the figure shows the anatomy of the heart okay there are three layers that compose the wall of the heart and the epicardium that protects the heart by reducing friction you have the myocardium and it's made mostly of the cardiac muscle tissue and then the endo is made up of epithelium and connective tissue and is aligning in the continuous it's continuous with the innermost lining of the blood vessels of the body the heart chambers the heart has four chambers two atria and two ventricles the um and then there's a septum that separates the two and then you have an intra ventricular septum and that separates the right and the left ventricle so each side of the heart contains one atrium and one ventricle the cardiac muscle is unique to the heart contraction occurs when calcium interferes with troponin and tryptomyosin the cardiac muscle fibers are long branching cells that fit together tightly and intracollated discs so the heart consists of two sets of chambers the atrial and the ventricular we talked about that and then you have heart valves the heart has four valves two atrial ventricular valves and two semilunar valves these valves direct the flow of blood between the chambers and prevent backflow so you have papillary muscles and that attached the um the basically the tendi and the endocardium of the ventricles and during ventricular contraction the av valves are closed because of the increase in the pressure of the chamber the sl valves separate the ventricles and their associated grape vessels these valves each have three cusps okay so the right sl valve is a pulmonic valve and the sl valve on the left is the aortic valve and this figure shows the heart valves and the cross-section of the heart valves so blood throw through the cardiovascular system you have systemic circulation and that's 85 pulmonary circulation is about 10 and then the heart chambers are about 5 okay so the cardiac cycle is a process that creates the pumping of the heart systole is a contraction of the ventricular mass and the pumping of blood into the systemic circulation diastole is the relaxation phase of the cycle and heart sounds so they're created by contraction and relaxation of the heart and the flow of the blood it's heard during auscultation with a stethoscope normal heart sound is lub dub s1 and s2 normal sounds s3 and s4 often not so abnormal sounds are murmurs or bruits clicks or snaps cardiac output is the amount of blood that is pumped by the ventricles in one minute stroke volume is the amount of blood ejected per contraction and the heart rate is the number of cardiac contractions per minute it's also known as the pulse rate okay so preload is the volume of blood in the ventricle at the end of diastole it's a reflection of the venous return after load it's the force against which the ventricles must contract to eject the blood and there are several ways of increasing this sv okay so sterling's law that's the contr cardiac muscle when stretch it'll contract with greater force and then coronary circulation so it is essential for the heart to have a reliable blood supply oxygenated blood reaches the heart through the coronary arteries you have two main coronary arteries and that's the left and right coronary arteries the left coronary artery divides into the left anterior descending and the circumflex the right coronary artery travels between the right and left atrium and the right ventricle by way of the atrioventricular groove the figure shows the two main arteries and their branches on this slide and then you have the conduction system of the heart so you have electrical stimuli it's controlled by the mechanical pumping action you have the conduction system the components are the sa node the av node the bundle of hiss the right and left bundle branches and the purkinje fibers the figure shows the electrical conduction of the heart on this slide you have the regulation of the heart function so the autonomic nervous system inerts the heart by means of the cardiac nerves branches of the vagus nerves provide parasympathetic inertia and networks of sympathetic and parasympathetic fibers perform various functions so factors that includes heart the heart rate that influence it are the stimulation of the sympathetic nerves electrolyte and hormone levels metabolic rate also medication stress anxiety and fear and body temperature when you talk about the blood vessels and the circulation of the cardiovascular system it's the vasculature and it can be divided into the arterial and the venous systems okay so the arterial systems is blood from heart to the tissues and the venous is one that returns the blood from the tissues to the heart the atrial system is the ascending aorta it originates from the base of the heart and terminates by becoming the arch of the aorta then you have the descending aorta it's named according to its location of the body cavities and then you have the aortic arch the types of arteries so you have conducting arteries and distributing arteries and then arterioles those are stop action through which blood is released to capillaries the figure shows the major veins and arteries okay so the arterial system the head and the neck you have the brachiocephalic artery it divides into the right common carotid artery in the right subclavian artery the upper extremities you have the subclavian artery it supplies both the brain neck interior chest wall and shoulder and then you have the thoracic artery and that's the visceral arteries that supply blood to the thoratic organs and then the parental arteries and they supply blood to the thoracic wall and then you have the intercostal arteries they run along the ribs and supply the chest walls you have the abdominal or aorta and basically branches of the abdominal aorta you could see on this slide in the pelvis and the lower extremities there are two common iliac arteries and they're divided into the internal iliac arteries and the external iliac arteries and they become together at the femoral arteries and then of course you have the vena system and those take the deoxygenated blood so back to the hearts so you have the smallest of the venous vessels they're very much smooth muscle in the middle layer venules are called storage vessels and the vena system contains about 70 percent of the blood body's blood veins adjust blood volume returning to the heart which is preload to meet the body's needs you have the pulmonary circulation and then you have the systemic circulation the head and the neck you two major veins that drain the head and the neck of blood are called the external and internal jugular veins venous sinuses are the primary means of venous drainage from the brain into the internal jugular vein so the upper um extremity you have major veins of the arm are the basilic vein and the cephalic vein you have the thorax abdominal pelvis and the hepatic portal circulation lower extremity the longest vein in the body is the great sephasius vein and it drains the foot the leg and the thigh so the microcirculation so this is the portion of the vasculature consisting of the arterioles capillaries and venules the most important functions of this microcirculation is that the transport of nutrients to tissues and the removal of cellular waste and it consists of like i said the capillaries and arterioles capillary filtration so many substances depend on the process for exchange of nutrients and waste products capillary filtration depends on three factors so the capillary membrane permeability arterial hydrostatic pressure and the venous pressure okay so the movement of water between the plasma in the intravascular compartment and the interstitial space is a result of pressure okay so you have two main forces the hydrostatic pressure and then the pressure of the osmotic pressure and it's exerted by proteins in the blood plasma all right so now we're moving on to the lymphatic system it's considered part of the circulatory system and it has three primary functions oval and recovery of fluid from tissues for water balance production and circulation of lymphocytes and distribution of various products unable to deliver the to the bloodstream directly so it transports lymph by passive circulation and lymph is a thin plasma-like fluid formed from interstitial and extracellular fluid that bathes the tissues of the body lymphatic capillaries pick up the lymph and drain it into larger vessels and the lymph circulates throughout the body in thin walled lymph vessels that travel close to the major arteries and veins and like veins lymphatic vessels contain valves that limit backflow foreign material is filtered from the lymph in the lymph nodes and foreign material returns to the main circulatory system via the thoratic duct movement of lymph is fluid influenced by body dynamics such as changes in respiratory pressure musculature contractions and movement of organs surrounding lymphatic vessels so when you talk about lymphatic vessels lymphatic vessels only carry fluid from the tissues and lymphatic capillaries are present in all tissues except the central nervous system bone marrow cartilage epidermis and cornea generally fluid flows from body capillaries to the tissues then out of the tissue spaces into lymph capillaries the thymus it's located in the thorax anterior to the aorta and posterior to the upper sternum it's divided into lobes by inward extending and it contains large amounts of lymphocytes including primarily an active thymocytes the spleen is located in the upper left abdominal cavity inferior to the diaphragm and posterior and lateral to the stomach the spleen is a largic lymphatic organ unlike the lymph nodes its venous sinuses are filled with blood not lymph and then the immune system has two components the lymph node tissues and the cells that are responsible for the immune response the two primary lymphanoid tissues are bone marrow in the thymus gland bone marrow specialized soft tissue found within the bone and then you have basically the lymph node tissues and the immune cells okay so then you have glands that produce antibodies and then they bathe mucous membranes so and the saliva it fights pathogens that enter the mouth and then although these play an important role in immunity the primary cells of the immune systems of course are the white blood cells so the respiratory system the primary function is to bring oxygen into the body and eliminate carbon dioxide the respiratory system also provides non-specific defenses against disease and also helps control ph and permits vocalization the respiratory system is composed of the respiratory tract the respiratory membrane the lungs and the diaphragm you have the upper and lower respiratory system so the upper respiratory system the structures are the nose mouth tongue jaw oral cavity larynx and pharynx and the major function of this upper respiratory system is to warm filter and humidify the air as it enters the body so we're just going to go through the upper airway and you have the first we'll start with the nasopharynx and the nasal passages and of course on the last slide we say said it was to warm filter and humidify the air when swallowing the muscles elevate the soft palate sealing off the nasopharynx from the oral pharynx this figure shows the upper airway including the oral cavity the larynx and the pharynx and then you have the oral pharynx and that begins at the level of the soft palate and extends to the epiglottitis or epiglottis the oral pharynx is the passageway for both air and food and the posterior pharynx has a rich supply of nerves stimulation of this area triggers the gag reflex the laryngopharynx extends from the epiglottis to the tip of the esophagus and for food and liquids pass through the esophagus air and other gases they enter the trachea the larynx joins the pharynx at the trachea it facilitates the passage of air functions as a sphincter and produces speech now that we've talked about the upper airway let's talk a little bit about the lower airway and so structures of the lower airway are the trachea bronchial tree and the alveoli and the lungs so the trachea connects the larynx to the lungs the bronchial tree airways leading from the trachea to the alveoli so it branches begins the right and left pulmonary bronchi each primary bronchus divides into secondary bronchus and tertiary and then even finer tubules each avlio duct ends at the alveoli respiratory exchange between the lung and blood vessels occurs in the alveoli and then the lungs so uh primary organs of breathing you have the right lung and it contains three lobes the left lung contains two and they're surrounded by pleura visceral pleura covers the lungs and folds back and be to become the parental pleura okay so it receives uh blood when deoxygenated blood flows from the right ventricle into the pulmonary arteries and oxygenated blood returns from the alveoli so lung volumes movement of substantial amount of air within the respiratory system you need tidal volume and that's the amount of air moved in a single breath inspiratory reserve volume is additional amount of air that can be inhaled after the normal tidal volume has been reached and then the expiratory reserve volume and that's an additional air amount of air that can be exhaled after the normal tidal volume is expelled residual volume well that's an air that remains in the lungs to keep them open you have the vital capacity and that's the amount of air moved with maximum inspiration and expiration the autonomic dead space and that has little to no alveoli and then the uh physiologic dead space and that's damaged alveoli so the minute volume one of the critical determinants of effecto ventilation so um one basically your minute volume equals your respiratory rate and your tidal volume ventilation is a process of moving air in and out of the lungs it's two separate phases and it's inhalation and exhalation each combination of inhalation and exhalation is a respiratory cycle so you have boyle's law and that is the pressure of the gas is inversely proportional to its volume negative pressure ventilation so that's drawing of air into the lungs airflow from a region of higher pressure outside the body to one of lower pressure exhalation of course is a passive process it does not require muscular effort or energy intrapleural pressure that's the pressure between the pleura of the lungs exhalation ends when the intrapleural pressure is equal to atmospheric pressure and this figure shows the mechanics of ventilation and oxygenation so we um so this is required air used for ventilation contains an adequate percentage of oxygen so oxygenation cannot occur without ventilation but ventilation is possible without oxygenation a fraction of inspired oxygen that's the percentage of oxygen in inhaled air so oxyhemoglobin curve so oxygen saturation is portional proportional to the amount of oxygen dissolved in the plasma component of the blood the relationship between that plasma component and the sao2 or spo2 is represented by the oxyhemoglobin curve when you talk about respiration that's the exchange of gases between the living organism and its environment it provides oxygen to the body while removing carbon dioxide and it's either external or internal first we'll talk about the external that's the pulmonary respiration and that's the exchange of gases between the alveoli of the lungs and the red blood cells traveling through the pulmonary capillaries then with internal respiration that is cellular respiration and that's when the gases exchange between the blood cells and the tissues in the bloodstream you could have anaerobic or aerobic so aerobic is oxygen and anaerobic is not containing oxygen so the role of diffusion it's when oxygen transfers from air into the capillaries in the alveoli partial pressure is the amount of gas in air or dissolved in liquids such as blood and it's governed by henry's law which states that as the pressure of a gas over a liquid decreases the amount of gas dissolved in the liquid will also decrease okay so the roll of diffusion it inspired air is a mixture of 75 nitrogen 21 oxygen and 0.04 carbon dioxide so what controls breathing and that's a regulation of ventilation involves a complex series of receptors and feedback loops that sense gas concentrations in the body fluids and then sends messages to the brain to adjust the rate and depth of ventilation there are three components and these centers are in the medulla oblongata and the pons right so it functions as the integration center and there's causes of inspiration or exploration and communicates information to both ventral and dorsal represent respiratory groups there are three components you have the effectors and those are the respiratory muscles and the sensors those are the chemoreceptors and the mechanical receptors and then the pro receptors chemoreceptors monitor variables they provide feedback to the receptorary centers basically so you have these essential chemoreceptors they're in the medulla and they respond to changes in carbon dioxide and the ph of the central or cerebral spinal fluid right and then the peripheral chemoreceptors in the carotid and aortic bodies respond to changes then you have the chemoreceptors respond to the medical conditions and traumatic injuries by stimulating respiratory control centers you also have lung receptors and those are basically in the bronchi bronchioles and visceral pleura and they are stimulated they stimulate when lungs inflate and then you have the irritant receptors and those are airway mucous membranes and those are stimulated by various irritants and allergens so there are buffer systems and they act as rapid defenses for acid-base changes respiratory and renal systems help maintain this homeostasis there are two major systems so we're going to move into the digestive system next you have the elementary canal and that's a series of muscular tubes that specialize along its length for processing of food and then you have the accessory digestive organs and they produce enzymes and juice is essential in the digestive process functions of the digestive system include ingestion mechanical processes digestion secretion absorption and excretion in succession different secretions primarily enzymes are added to the food by this saliva glands the stomach the liver the pancreas and the small intestines these organs convert the food into basic sugars fatty acids and amino acids the products of digestion are carried across the interstitial wall and transmitted through portal vein to the liver in the liver the products are processed further and stored or transported to the heart through veins draining the liver the hue the heart then pumps the blood with these nutrients through the arteries to the capillaries where the nutrients pass through the capillary walls to nourish the body cells the elementary channel extends from the mouth to the anus and includes the mouth pharynx esophagus stomach intestines rectum and anus okay the walls of the canal consists of mucosa submucosa muscular layer and serosa this figure shows the layers of the stomach and the layers of the intestines and this figure shows the layers of the stomach and the layers of the intestines the accessory organs of the canal include the teeth tongue saliva glands liver gallbladder and pancreas okay so the abdomen so we divide the abdomen into those four quadrants the right upper quadrant is the liver gallbladder sum of the spleen and some of the small intestines the left upper quadrant is the stomach spleen some of the colon and the small intestines the right lower is the semicolon in the appendix and the left lower is this descending parts of the colon some parts are in more than one quadrant of course these figures show the locations of the different organs in the abdomen okay so you have the oral cavity it consists of the lips cheeks gums teeth and tongue it's lined by mucous membranes you have the hard and soft palate and four teeth quadrants and the saliva glands secretes saliva with food and during mastiffication these figures show the teeth glands and the muscles of the mouth right you have the esophagus and it's a collapsible tube about 10 inches long it extends from the end of the pharynx to the stomach it transports food from the mouth to the stomach and contractions of the muscle propel food to the stomach then you have the stomach it's a hollow organ in the left upper quadrant receives food stores it and moves it into the small intestines in small amounts converts food to mixed mass and these figures show the small and large intestines then you have the small intestines it's a major hollow organ of the abdomen it absorbs about 90 percent of products of digestion into veins to transport to the liver and then the large intestines it encircles the outer abdomen around the small intestines it completes the reabsorption of water and forms solid stool to pass out of the body through the anus the liver is a complex organ with many functions and maintains blood glucose it detoxifies the blood manufactures plasma proteins and manufactures clotting factors it also regulates fats it's highly vascular organ through which 100 of the body's blood circulates the gallbladder is an basically an out poaching from the bile ducts it serves as a reservoir for bile and food triggers a release of bile from the gallbladder the pancreas has endocrine and exocrine factors and both the endocrine functions are the synthesis of glucagon insulin and somostatin and the exocrine is it produces pancreatic digestive juices when you talk about the digestion and absorption of nutrients metabolism is the sum of all chemical and biological reactions of an organism so the term is describes the rate at which the body processes the food and the body obtains nutrients by inhalation such as oxygen in ingestion such as food digestion breaks down nutrients so they can be absorbed and transported via the bloodstream and nutrients are grouped as macro nutrients and that's large amounts that provide energy such as carbohydrates and micro nutrients and those require smaller amounts and allow energy extraction from the macro nutrients such as vitamins and minerals digestion handles each of the components differently so energy from carbohydrates mostly is used to power cellular processes digestion breaks down carbohydrates into monosaccharides for easy absorption many cells get their energy by oxidizing fatty acids through neurons required continuous glucose to survive and when carbohydrates are not consumed sufficiently the liver may convert amino acids into glucose some excess glucose is changed to glycosyn and it's stored in the liver and muscles glucose can be rapidly mobilized from the glycogen but only a certain amount of glycogen can be stored so excess glucose is usually converted into fat and stored in adipose tissue and for energy the body's first first metabol metabolizes glucose then glycogen then glu into glucose and lastly fats and proteins all right so now we're into the urinary system it controls discharge of waste filtered from the bot blood by the kidneys the functions are to control fluid balance and filter and eliminate waste and then control the ph the components are the kidney ureters urinary bladder and urethra so the kidneys they regulate uh ph and volume of extracellular fluid they regulate water and electrolytes acid-base balance and products and foreign chemicals they excrete hormones and regulate arterial blood pressure and producing new glucose so there's three areas the renal cortex renal medulla and the renal pelvis about 1 million nephrons are in the kidney and then you could see what the the nephrons consist of so they basically consist of those five things okay so this capsule composed of the red corpuscle and the blood enters and the pores in the capillary walls filter that blood filtered water and waste flow from those capped from the capsule through the renal tubules so urea is the result of amino acid basically catabolism and uric acid is a result of the metabolism of certain organic bases in nucleic acids urine is about 95 water and it contains urea and uric acid urine is drained from each kidney through those tubes called ureters and um basically contractions move the urine out of the kidneys along the ureters and towards the urinary bladder once they get to the urinary bladder that's a hollow muscular sac surrounded by smooth muscle stretching of the bladder wall stimulates the nerve impulses to produce a reflex and that's an urge to void is produced by pressure in the urinary sphincter the brain keeps the external urinary sphincter contracted until conditions are favorable for urination in the urinary bladder and the urethra make up the lower urinary tract so when it comes to fluid balance there are mechanisms in the body that balance between what is taken in and out so adh allows fluid volume to build up thirst stimulates intake kidneys stimulate the excretion and the water shifts extracellular to intracellular okay so next we're going to talk about the reproductive system and um basically they're gamites which are sex cells so sperm and eggs they carry genetic instructions and the physical traits are determined by dominant and recessive genes so the male reproductive system is all these structures and the primary sex origin organs consist of two testes that's where the sperm cells and the sex hormones are formed accessory glands include vesicles prostate gland and other glands the testes produce testosterone and sperma genetic tubules for sperm cells and interstitial cells secrete the testosterone okay so on this slide you're gonna see the process of meiosis and to reach outside the body sperm cells must travel through a series of ducts and you have all the ducts listed on the slide take a look at that seminal vessels secrete a fluid that contains fructose and carbohydrates to provide energy for that sperm the prostate gland secretes fluid that enhances sperm mobility and prevents urine flow and then you have other glands that secrete mucus-like fluid lubricating the end of the penis semen is released during ejaculation and it's made up of prosthetic fluids so it's about 30 and uh vesicle fluid is about 60 and then 10 is sperm about 2 to 5 milliliters of semen is released at one time you have the external reproductive organs and that's the scrotum penis and it's the root body in the shaft which is the shaft and glands and then you have the female reproductive anatomy so you have the ovaries and they perform three functions production of the immature female basically eggs secretion of the female hormones and then secretion of the inhibition so the process of cell and egg formation it's fertilized and divides and produces a fertilized egg which is a zygote if the fertilization does not occur basically it's expelled from the uterus during menstruation okay this figure shows the follicle development and the ogenesis so the menstrual cycle menstruation is uh basically vaginal discharge of blood and epithelial cells mucus and tissue the duration of the cycle ranges from 25 to 35 days monarch is the onset of the first menses and it occurs when the girl reaches child bearing age usually between 11 and 14. menopause is the last and it occurs when a woman reaches the end of child bearing age typically about 40 to 50 years old okay and this figure shows the menstrual cycle based on the average 28-day cycle and you could see those the different days so the female internal accessory organs you have the fallopian tubes the uterus and the vagina breast and mammillary glands and then hormones okay so this completes the anatomy and physiology chapter chapter eight if you've uh liked the second part of this lecture and haven't seen the first go to part one and thank you and have a great day