Overview
This lecture reviews essential concepts in human anatomy and physiology for the ATI TEAS 7 Science exam, covering major body systems, their functions, and exam-critical definitions and mechanisms.
Respiratory System
- Air enters via nasal cavity, is filtered and warmed.
- The pharynx directs air to the larynx and trachea; food is routed to the esophagus.
- The trachea splits into bronchi, leading to lungs (3 lobes right, 2 lobes left).
- Bronchi branch into bronchioles ending in alveoli where gas exchange occurs.
- Conducting zone (trachea, bronchi) moves air; respiratory zone (alveoli) is for gas exchange.
- Diaphragm and intercostal muscles control breathing; pH and CO₂ levels regulate respiration.
Circulatory System
- Blood is always red; veins and arteries are color-coded in diagrams only.
- Arteries carry blood away from the heart; veins return blood to the heart.
- Pulmonary arteries carry oxygen-poor blood; pulmonary veins return oxygen-rich blood.
- Heart has 4 chambers: right/left atria (top), right/left ventricles (bottom).
- Blood flow: veins → right atrium → right ventricle → lungs → left atrium → left ventricle → body.
- Heart valves prevent backflow; coronary arteries supply heart muscle.
- Septal defects cause mixing of oxygenated/deoxygenated blood.
Nervous System
- Central nervous system (CNS): brain and spinal cord; peripheral nervous system (PNS): nerves.
- Brain divided into hindbrain (medulla, pons, cerebellum), midbrain, and forebrain (cerebrum).
- Neurons have cell body, axon, axon terminal; glial cells support neurons.
- Sensory (afferent) neurons bring info to CNS; motor (efferent) neurons send info out.
- Somatic nervous system controls voluntary muscles; autonomic nervous system regulates organs (sympathetic = "fight or flight," parasympathetic = "rest and digest").
Digestive System
- Four functions: ingestion, digestion, absorption, elimination.
- Mouth begins mechanical and chemical digestion (salivary amylase).
- Stomach uses acid and enzymes for protein digestion; pyloric sphincter controls passage to small intestine.
- Small intestine: duodenum (digestion), jejunum (absorption), ileum (absorbs B12 and bile salts).
- Large intestine absorbs water, stores waste, and prepares for elimination.
- Accessory organs: liver (produces bile), gallbladder (stores bile), pancreas (enzymes, insulin).
- Key hormones: gastrin, cholecystokinin, secretin, insulin, glucagon; bile emulsifies fats.
Muscular System
- Three muscle types: cardiac (heart, involuntary), smooth (organs, involuntary), skeletal (bones, voluntary).
- Muscle contractions occur via the sliding filament model: actin (thin), myosin (thick) slide past each other.
- ATP is needed for muscle contraction and relaxation.
Reproductive System
- Gonads produce gametes: testes (sperm, testosterone), ovaries (eggs, estrogen, progesterone).
- Male: sperm produced in seminiferous tubules, matures in epididymis, expelled via vas deferens and urethra.
- Female: oogenesis occurs in ovaries; ovulation releases an egg into fallopian tubes for possible fertilization in uterus.
- Hormone regulation: LH and FSH (from pituitary) control gamete production and sex hormone secretion.
Integumentary System (Skin)
- Skin regulates temperature, prevents fluid loss, provides protection, and synthesizes vitamin D.
- Layers: epidermis (stratum corneum to basale), dermis (connective tissue, nerves), hypodermis (fat).
- Melanocytes make melanin; keratinocytes make keratin; fibroblasts make collagen/elastin.
- Accessory structures: sweat glands (cooling), sebaceous glands (oil), hair, nails.
- Burns categorized by depth (first-fourth degree); skin cancer risk from UV exposure.
Endocrine System
- Endocrine glands secrete hormones directly into blood; exocrine glands use ducts.
- Major glands: hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, gonads.
- Hormones regulate metabolism (thyroid), calcium (PTH, calcitonin), stress (cortisol, adrenaline), glucose (insulin, glucagon), and reproduction (estrogen, testosterone).
Urinary System
- Organs: kidneys (filter waste, regulate water/solutes), ureters, bladder, urethra.
- Nephron is the functional unit: filtration (glomerulus/Bowman's capsule), reabsorption, secretion, excretion.
- Hormones (e.g., ADH) regulate water reabsorption; urine expels metabolic waste.
Immune System
- Defends against pathogens with innate (non-specific) and adaptive (specific) immunity.
- Barriers: skin, mucous membranes.
- Inflammatory response: histamine increases blood flow and permeability.
- Adaptive immunity: cell-mediated (T cells) and humoral (B cells/antibodies).
- Immunity can be active (produced by self, e.g., vaccines) or passive (antibodies from another source).
Skeletal System
- Supports body, protects organs, produces blood cells (hematopoiesis), stores minerals, enables movement.
- Axial skeleton: head, vertebral column, rib cage; appendicular: limbs, girdles.
- Bone types: long, short, flat, irregular, sesamoid.
- Internal bone: compact (outer) and spongy (inner, marrow).
- Cells: osteoblasts (build), osteocytes (maintain), osteoclasts (break down).
- Bone remodeling involves cycles of resorption and formation; fractures heal via callus formation.
Anatomical Terminology & Planes
- Directional terms: anterior (front), posterior (back), medial (toward midline), lateral (away from midline), superior (above), inferior (below), proximal (closer), distal (farther).
- Body planes: transverse (upper/lower), frontal/coronal (front/back), sagittal (left/right).
Key Terms & Definitions
- Nephron — kidney's microscopic filtering unit.
- Alveoli — tiny lung sacs for gas exchange.
- Osteoblasts — bone-forming cells.
- Osteoclasts — bone-resorbing cells.
- Sarcomere — muscle's basic contractile unit.
- Antibody — immune protein targeting specific antigens.
- Insulin — hormone lowering blood glucose.
- Glucagon — hormone raising blood glucose.
- Active Immunity — immunity from body’s own antibody production.
- Passive Immunity — immunity from external antibodies.
Action Items / Next Steps
- Review diagrams of body systems, especially circulation and nephron structures.
- Memorize hormone functions and key anatomical terms/planes.
- Practice tracing blood flow and urine formation pathways.
- Complete relevant homework or practice questions listed in class materials.