Comprehensive Human Anatomy and Physiology Review for Independent Learners

What is homeostasis?

The body's ability to maintain a stable internal environment despite external changes.

What are the body positions prone and supine?

Prone = face down; Supine = face up.

What are the three body planes?

Sagittal (left/right), Frontal/Coronal (front/back), Transverse (top/bottom).

What do the directional terms proximal and distal mean?

Proximal = closer to the point of attachment; Distal = farther from the point of attachment.

What do ventral and dorsal mean?

Ventral = front/belly side; Dorsal = back side.

What do medial and lateral mean?

Medial = toward the midline; Lateral = away from the midline.

What are the four biomolecules and what parts of the cell are made from each?

Carbohydrates (energy/cell coat), Lipids (cell membrane), Proteins (enzymes, receptors, structural), Nucleic acids (DNA/RNA).

What is diffusion?

The passive movement of molecules from high to low concentration.

What is osmosis?

The diffusion of water across a semipermeable membrane from low to high solute concentration.

What is facilitated diffusion?

Passive transport of molecules across a membrane via protein channels, down the concentration gradient.

What is active transport?

Movement of molecules against the concentration gradient, requiring energy (ATP).

What are hypertonic, hypotonic, and isotonic solutions?

Hypertonic = more solute than cell (cell shrinks); Hypotonic = less solute than cell (cell swells); Isotonic = equal solute concentration (no net movement).

What is pH and what role does it play in physiology?

pH measures acidity/alkalinity; enzymes and proteins function only within specific pH ranges, so pH regulation is critical for homeostasis.

What are the three layers of skin and where is each found?

Epidermis (outermost), Dermis (middle), Hypodermis/Subcutaneous layer (deepest).

Which layer of the skin has cell division?

The stratum basale of the epidermis.

Which layer of skin can be seen?

The epidermis (specifically the stratum corneum).

What tissue types make up the epidermis?

Stratified squamous epithelium.

What is the role of skin in thermoregulation and UV protection?

Sweat glands cool the body; melanin absorbs UV radiation to protect DNA.

Which sweat glands release water vs. odorants?

Eccrine glands release water (cooling); Apocrine glands release odorants.

What provides normal skin color? What causes jaundice?

Melanin provides normal skin color; jaundice is caused by buildup of bilirubin, giving skin a yellow tint.

What is the general structure of a bone and the purpose of each part?

Periosteum (outer covering), compact bone (strength), spongy bone (lightweight/marrow), medullary cavity (holds yellow marrow), epiphysis (ends), diaphysis (shaft).

What is the key ion in bone mineralization?

Calcium (Ca²⁺).

What hormones control calcium storage and how?

Calcitonin (CT) lowers blood calcium by storing it in bone; Parathyroid hormone (PTH) raises blood calcium by releasing it from bone.

What is found at the ends of long bones?

Articular cartilage covers the epiphysis; the epiphyseal (growth) plate is where bone lengthening occurs.

What caps and protects the ends of long bones?

Articular (hyaline) cartilage.

What is the difference between the appendicular and axial skeleton?

Axial = skull, vertebral column, rib cage; Appendicular = limbs and girdles.

What are the 3 types of joints and their roles?

Fibrous (immovable, e.g. skull sutures), Cartilaginous (slightly movable, e.g. vertebrae), Synovial (freely movable, e.g. knee).

What are the roles of actin and myosin in muscle contraction?

Myosin heads pull actin filaments toward the center of the sarcomere during the power stroke, shortening the muscle.

How are actin and myosin arranged in a sarcomere?

Actin (thin filaments) extend from Z-lines; myosin (thick filaments) are in the center between actin filaments.

What role does calcium from the sarcoplasmic reticulum play in muscle contraction?

Calcium binds to troponin, moving tropomyosin off actin binding sites, allowing myosin heads to attach and initiate contraction.

What is the difference between the central and peripheral nervous system?

CNS = brain and spinal cord; PNS = all nerves outside the brain and spinal cord.

What are the sub-branches of the motor and sensory divisions of the PNS?

Sensory (afferent) brings signals to CNS; Motor (efferent) carries signals away; Motor divides into somatic (voluntary) and autonomic (involuntary).

What is the sympathetic vs. parasympathetic nervous system?

Sympathetic = fight-or-flight (motor); Parasympathetic = rest-and-digest (motor). Both are motor divisions of the autonomic nervous system.

What is the basis of an action potential?

A rapid change in membrane potential caused by the influx of Na⁺ (depolarization) followed by efflux of K⁺ (repolarization).

What is the difference between a membrane at RMP, depolarized, and hyperpolarized?

RMP ≈ -70mV (resting); Depolarized = less negative (Na⁺ flows in); Hyperpolarized = more negative than RMP (K⁺ flows out extra).

What are the meninges and where are they located?

Three protective layers around the CNS: Dura mater (tough outer), Arachnoid mater (middle, web-like), Pia mater (thin inner, directly on brain/cord).

In spinal cord organization, where is grey vs. white matter, and which root is sensory?

Grey matter is in the center (H-shape); White matter is on the outside. Dorsal root = sensory; Ventral root = motor.

How does grey/white matter arrangement in the spinal cord compare to the brain?

Spinal cord: grey inside, white outside. Brain: grey outside (cortex), white inside.

Why are nerves white and what is myelin made from?

Myelin is a lipid-rich (fatty) sheath produced by Schwann cells (PNS) or oligodendrocytes (CNS); lipids appear white.

What do the medulla, pons, cerebellum, and thalamus do?

Medulla = autonomic functions (breathing, heart rate); Pons = relay, breathing rhythm; Cerebellum = coordination/balance; Thalamus = sensory relay station.

What are the first 3 cranial nerves and their functions?

CN I - Olfactory (smell); CN II - Optic (vision); CN III - Oculomotor (eye movement).

What is CN I?

Olfactory (smell)

What is CN II?

Optic (vision)

What is CN III?

Oculomotor (eye movement)

How does hormone action differ from neurotransmitter action?

Neurotransmitters act quickly at a synapse; hormones travel through the bloodstream and act more slowly on distant target cells.

How do steroid hormones act differently from protein hormones?

Steroids are lipid-soluble and cross the cell membrane to bind intracellular receptors; protein hormones bind surface receptors and use second messengers.

How does the hypothalamus control the pituitary?

The hypothalamus releases releasing/inhibiting hormones that regulate the anterior pituitary and produces ADH and oxytocin stored in the posterior pituitary.

What is the difference between the anterior and posterior pituitary?

Anterior pituitary produces and secretes its own hormones; posterior pituitary releases hormones made by the hypothalamus.

What gland controls blood glucose and through what hormones?

The pancreas; insulin lowers glucose and glucagon raises glucose.

What do the adrenal glands do and where are they found?

Located on top of the kidneys; adrenal cortex releases cortisol and aldosterone; adrenal medulla releases epinephrine and norepinephrine.

Which layer of the uterine wall responds to oxytocin?

The myometrium (smooth muscle layer).

What hormones are needed in males for gametogenesis and steroidogenesis?

FSH stimulates sperm production; LH stimulates testosterone production.

What hormones during the menstrual cycle cause gametogenesis, ovulation, and prevent new ova formation?

FSH causes gametogenesis; LH surge causes ovulation; Estrogen & Progesterone prevent new ova formation.

Which hormones are made in the gonads vs. the pituitary, and what are they responsible for?

Gonads produce sex steroids; Pituitary produces FSH and LH to regulate gonad activity.

Compare and contrast the follicle and corpus luteum.

Follicle develops before ovulation, produces estrogen; Corpus luteum forms after ovulation, produces progesterone and estrogen.

What is the alimentary canal from mouth to anus?

Mouth → pharynx → esophagus → stomach → small intestine → large intestine → rectum → anus.

What part of the small intestine does digestion take place?

Digestion primarily in the duodenum; absorption primarily in the jejunum and ileum.

How does chyme differ from a bolus in terms of pH?

Bolus is neutral/slightly alkaline; chyme is acidic (pH ~2).

What makes bile, what absorbs water, and what prevents choking?

Liver makes bile; large intestine absorbs water; epiglottis prevents choking.

How does amylase differ from pepsin in function?

Amylase breaks down carbohydrates; pepsin breaks down proteins.

What is the difference between internal and external respiration?

External respiration is gas exchange between lungs and blood; internal respiration is gas exchange between blood and body tissues.

Where do bronchioles terminate?

At alveoli (alveolar sacs), where gas exchange occurs.

Where are the vocal cords located?

In the larynx (voice box).

What is ventilation?

The mechanical process of breathing — moving air in and out of the lungs.

What is the difference between arteries and veins?

Arteries carry blood away from the heart; veins carry blood toward the heart.

Which vessels feed capillaries and which drain them?

Arterioles feed capillaries; venules drain capillaries.

What force brings fluid out of capillaries and what force brings it back?

Hydrostatic pressure pushes fluid out; osmotic pressure pulls fluid back in.

What are the 4 chambers of the heart?

Right atrium, right ventricle, left atrium, left ventricle.

What is the difference between the bicuspid and tricuspid valves?

Tricuspid is on the right side; bicuspid (mitral) is on the left side.

SVC vs. IVC — from where does each bring blood?

SVC brings blood from the upper body; IVC brings blood from the lower body.

What nerve governs heart rate and through what structure in the right atrium?

The vagus nerve slows heart rate; it acts on the SA node.

Which blood cells make antibodies, carry oxygen, clot, and phagocytose invaders?

B lymphocytes (antibodies); Red blood cells (oxygen); Platelets (clotting); Neutrophils/macrophages (phagocytosis).

What blood type is the universal donor?

Universal donor = Type O negative.

What is the functional unit of the kidney?

The nephron.

What does the urinary bladder do?

Stores urine.

What tubes enter and leave the renal hilum?

Renal artery enters; renal vein and ureter exit.

Through what 2 processes does the kidney clean blood?

Filtration and reabsorption.

Where do filtration and reabsorption occur in the nephron?

Filtration at the glomerulus; reabsorption primarily in the proximal convoluted tubule.

What is the primary source of toxicity in the blood?

Ammonia/urea from protein metabolism.