Anatomy, Physiology & Medical Terminology

Understanding the anatomy (structure) and physiology (function) of the human body is foundational knowledge for every medical assistant. The CMA exam tests your ability to identify body structures, understand their functions, and apply medical terminology correctly.

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Body Organization

The body is organized from simplest to most complex:

Four Basic Tissue Types

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The 11 Organ Systems

Cardiovascular System

• Heart: 4 chambers (right atrium, right ventricle, left atrium, left ventricle)
• Blood vessels: Arteries (carry blood away from heart), veins (carry blood to heart), capillaries (exchange site)
• Blood flow path: Right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body
• Cardiac output: ~5 liters/minute at rest
• Cardiac conduction: SA node (pacemaker) → AV node → Bundle of His → Purkinje fibers
• Key terms: Systole (contraction), diastole (relaxation), tachycardia (>100 bpm), bradycardia (<60 bpm)
• Common conditions: Myocardial infarction (heart attack), congestive heart failure, hypertension, arrhythmias

Respiratory System

• Upper: Nose, pharynx, larynx
• Lower: Trachea, bronchi, bronchioles, alveoli
• Function: Gas exchange — O2 in, CO2 out at the alveolar-capillary membrane
• Normal adult respiratory rate: 12-20 breaths/min
• Lung volumes: Tidal volume (~500 mL), vital capacity (~4,600 mL), residual volume (~1,200 mL)
• Key terms: Dyspnea (difficulty breathing), apnea (absence of breathing), hypoxia (low oxygen), hypercapnia (high CO2)
• Common conditions: Asthma, COPD (emphysema, chronic bronchitis), pneumonia, tuberculosis

Digestive (Gastrointestinal) System

• Pathway: Mouth → esophagus → stomach → small intestine (duodenum, jejunum, ileum) → large intestine (colon) → rectum → anus
• Accessory organs: Liver (produces bile, detoxification), gallbladder (stores bile), pancreas (enzymes and insulin)
• Function: Mechanical and chemical digestion, nutrient absorption, waste elimination
• Key enzymes: Amylase (carbohydrates), pepsin (proteins in stomach), lipase (fats), trypsin (proteins in small intestine)
• Key terms: Peristalsis (wave-like muscle contractions), emesis (vomiting), dysphagia (difficulty swallowing)
• Common conditions: GERD, peptic ulcer disease, Crohn's disease, ulcerative colitis, diverticulitis

Endocrine System

• Glands: Pituitary (master gland), thyroid, parathyroid, adrenal, pancreas (islets of Langerhans), ovaries, testes, pineal, thymus
• Function: Hormone production and regulation of metabolism, growth, reproduction, and homeostasis
• Key hormones: Insulin (lowers blood glucose), glucagon (raises blood glucose), thyroxine (T4, metabolism), cortisol (stress response), estrogen, testosterone, growth hormone
• Feedback mechanisms: Negative feedback loops maintain homeostasis (e.g., high glucose → insulin release → glucose drops → insulin stops)
• Common conditions: Diabetes mellitus (Type 1 and Type 2), hypothyroidism, hyperthyroidism, Cushing syndrome, Addison disease

Nervous System

• CNS: Brain and spinal cord
• PNS: Cranial nerves (12 pairs) and spinal nerves (31 pairs)
• Autonomic: Sympathetic (fight or flight) and parasympathetic (rest and digest)
• Neuron structure: Dendrites (receive signals) → cell body → axon (transmits signals) → axon terminals (release neurotransmitters)
• Key terms: Neuron (nerve cell), synapse (gap between neurons), neurotransmitter (chemical messenger)
• Common conditions: Alzheimer disease, Parkinson disease, multiple sclerosis, epilepsy, stroke (CVA)

Musculoskeletal System

• Bones: 206 in the adult skeleton; provide support, protection, movement, mineral storage, and blood cell production (hematopoiesis)
• Muscles: 600+ skeletal muscles; types include skeletal (voluntary), smooth (involuntary), and cardiac
• Joints: Synovial (freely movable), cartilaginous (slightly movable), fibrous (immovable)
• Skeletal divisions: Axial skeleton (skull, vertebral column, rib cage) and appendicular skeleton (limbs, shoulder girdle, pelvic girdle)
• Key terms: Fracture (bone break), osteoporosis (bone density loss), arthritis (joint inflammation)
• Common conditions: Osteoarthritis, rheumatoid arthritis, osteoporosis, herniated disc, carpal tunnel syndrome

Urinary System

• Organs: Kidneys (2), ureters (2), bladder (1), urethra (1)
• Function: Filtration of blood, waste removal, fluid and electrolyte balance, blood pressure regulation, acid-base balance
• Nephron: Functional unit of the kidney — filters blood to produce urine (glomerulus → Bowman's capsule → tubules → collecting duct)
• Normal urine output: 30-50 mL/hour in adults; 1,000-2,000 mL/day
• Common conditions: Urinary tract infection (UTI), kidney stones (nephrolithiasis), chronic kidney disease, acute renal failure

Reproductive System

• Male: Testes (sperm and testosterone), epididymis, vas deferens, prostate gland, penis
• Female: Ovaries (eggs and estrogen/progesterone), fallopian tubes, uterus, cervix, vagina
• Menstrual cycle: Approximately 28 days; phases include menstrual, follicular, ovulation, and luteal
• Common conditions: Benign prostatic hyperplasia, prostate cancer, endometriosis, polycystic ovary syndrome, cervical cancer

Integumentary System

• Layers: Epidermis (outer), dermis (middle), subcutaneous/hypodermis (deepest)
• Accessory structures: Hair, nails, sweat glands (sudoriferous), sebaceous (oil) glands
• Functions: Protection, temperature regulation, sensation, vitamin D synthesis, excretion
• Key terms: Dermatitis (skin inflammation), cyanosis (blue skin), jaundice (yellow skin), erythema (redness)
• Common conditions: Eczema, psoriasis, skin cancer (basal cell, squamous cell, melanoma), burns

Lymphatic/Immune System

• Organs: Lymph nodes, spleen, thymus, tonsils, bone marrow
• Function: Fluid drainage, immune defense, fat absorption from GI tract
• Immunity types: Innate (natural, nonspecific) and adaptive (acquired, specific — antibodies)
• Key terms: Lymphocytes (T cells and B cells), antibodies (immunoglobulins), antigens
• Common conditions: HIV/AIDS, lupus (SLE), allergies, lymphoma

Sensory System

• Eye: Cornea, iris, pupil, lens, retina (rods for dim light, cones for color); common conditions include myopia (nearsightedness), hyperopia (farsightedness), cataracts, glaucoma
• Ear: Outer ear, middle ear (tympanic membrane, ossicles), inner ear (cochlea for hearing, semicircular canals for balance)
• Common conditions: Otitis media (middle ear infection), hearing loss, vertigo, macular degeneration

Medical Terminology Structure

Medical terms follow a consistent pattern that allows you to decode unfamiliar words:

PREFIX + ROOT WORD + SUFFIX

Common Prefixes

Common Root Words

Common Suffixes

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Body Planes & Directional Terms

Body Planes

Directional Terms

Body Cavities

Abdominal Quadrants