Chapter 6: The Human Body Lecture

Objectives

• Describe and apply in context the body planes, topographic anatomy, and the atomic position.
• Identify basic anatomical structures and related functions.
• Describe each body system, their structures, roles, and interactions.
• Discuss consequences of illnesses and injuries on these structures and systems.

Anatomy & Terminology

• Anatomy: Study of physical structure of the body and its systems.
• Physiology: Study of normal functions and actions of the body and its systems.
• Pathophysiology: Study of functional changes accompanying disease or syndrome.

Topographic Anatomy

• Anatomic Position: Body standing facing forward, arms at side, palms forward.
• Body Planes: Imaginary lines dividing the body:
  • Coronal (Frontal) Plane: Divides front and back.
  • Sagittal Plane: Divides left and right.
  • Mid-Sagittal Plane: Special type of sagittal plane, divides into equal left and right halves.
  • Transverse (Axial) Plane: Divides top and bottom.

From Cells to Systems

• Cells: Foundation of the human body.
• Tissue: Cells with common function.
• Organs: Group of tissues with interrelated jobs.
• Body System: Organ systems with similar functions working together.

Skeletal System

• Functions: Provides human form, protects vital organs.
• Divisions:
  • Axial Skeleton: Skull to coccyx (center of body).
  • Appendicular Skeleton: Extremities and their connection points to axial skeleton.
• Bones: 206 total in the body.
• Joints: Where bones meet.
  • Ligaments: Connect bone to bone.
  • Cartilage: Cushions ends of bones.
  • Tendons: Attach bone to muscle.
  • Types of Joints:
    • Ball and Socket: Rotation and bending.
    • Hinge Joint: Flexation and extension (e.g., elbow, knee).

Axial Skeleton Details

• Skull: 28 bones (cranium, facial bones, ear bones).
  • Cranium: Occipital, temporal, parietal, frontal bones.
  • Facial Bones: Maxilla, zygomas, mandible, orbits, nasal bones.
• Spinal Column: 33 vertebrae in 5 sections.
  • Cervical Spine: 7 vertebrae.
  • Thoracic Spine: 12 vertebrae.
  • Lumbar Spine: 5 vertebrae.
  • Sacrum: 5 fused vertebrae.
  • Coccyx: 4 fused vertebrae.
• Thorax: 12 thoracic vertebrae, 12 pairs of ribs, sternum.

Appendicular Skeleton Details

• Upper Extremities: Clavicle, scapula, humerus, radius, ulna, carpals, metacarpals, phalanges.
• Pelvic Girdle: Ilium, ischium, pubis, sacrum, coccyx.
• Lower Extremities: Femur, tibia, fibula, tarsals, metatarsals, phalanges.

Physiology of Skeletal System

• Functions:
  • Provides shape.
  • Protects organs.
  • Allows movement.
  • Stores calcium.
  • Creates blood cells.
• Types of Muscles:
  • Skeletal Muscle: Voluntary muscle, movement and environmental interaction.
  • Smooth Muscle: Involuntary muscle, within blood vessels and intestines.
  • Cardiac Muscle: Heart muscle.

Respiratory System

• Functions: Breathing (respiration), oxygen/carbon dioxide exchange.
• Divisions:
  • Upper Airway: Nose, mouth, tongue, jaw, larynx, pharynx, trachea, epiglottis.
  • Lower Airway: Thyroid cartilage, cricoid cartilage, cricothyroid membrane, trachea, bronchi, lungs.
• Lungs: Right lung (3 lobes), left lung (2 lobes).
• Mechanism of Breathing:
  • Diaphragm and Intercostal Muscles.
  • Inhalation: Active, diaphragm contracts, negative pressure.
  • Exhalation: Passive, diaphragm relaxes, air flows out.
• Physiology of Respiration:
  • Chemical control by brainstem.
  • Ventilation: Air movement between lungs/environment.
  • Respiration: Gas exchange in alveoli.
  • Control Centers: Medulla oblongata, pons.
  • Tidal Volume: Amount of air per breath.

Circulatory System

• Functions: Transport oxygen/nutrients, remove waste.
• Components:
  • Heart: Myocardium muscle, involuntary.
  • Vessels: Arteries, arterioles, capillaries, venules, veins.
  • Blood: Plasma, red blood cells, white blood cells, platelets.
• Heart Mechanics:
  • Electrical conduction system: SA node, AV node, Bundle of His, Purkinje fibers.
  • Valves ensure unidirectional flow.
• Blood Pressure: Systolic (contraction), Diastolic (relaxation).

The Nervous System

• Divisions: Central (CNS) and Peripheral (PNS).
  • CNS: Brain, spinal cord.
  • PNS: Nerves outside CNS, subdivided into Somatic (voluntary) and Autonomic (involuntary).
• Brain: Cerebrum, cerebellum, brainstem (midbrain, pons, medulla oblongata).
• Peripheral: Sensory nerves (to CNS) and motor nerves (from CNS).

Integumentary (Skin) System

• Layers: Epidermis, dermis.
• Functions: Protects body, regulates temperature, transmits environmental information.

Digestive System

• Components:
  • Mouth, esophagus, stomach, intestines (small and large), liver, pancreas.
  • Accessory Organs: Gallbladder, appendix, rectum.
• Functions: Breakdown and absorption of nutrients, waste elimination.

Lymphatic System

• Components: Spleen, lymph nodes, lymph vessels, thymus gland.
• Functions: Supports immune system, removes toxins.

Endocrine System

• Function: Hormone regulation and control.
• Glands: Produce hormones directly into bloodstream.
• System Control: Primary and secondary feedback loops.

Urinary System

• Components: Kidneys, ureters, bladder, urethra.
• Functions: Fluid balance, waste filtration/elimination, pH control.

Genital System

• Male Reproductive System: Testes, prostate, seminal vesicles, penis.
• Female Reproductive System: Ovaries, fallopian tubes, uterus, cervix, vagina.

Life Support Chain

• Cells: Need oxygen, nutrients, waste removal.
• Systems: Respiratory and Circulatory deliver essentials.

Pathophysiology

• Respiratory Compromise: Hypoxia, hypercarbia.
• Shock: Inadequate blood flow, leading to cell death.
• Metabolic Acidosis: Result of anaerobic metabolism.