Anatomy and Physiology

A Comprehensive Study Chapter for the NHA CCMA Exam

Learning Objectives

Upon completion of this chapter, you will be able to:

6.Identify the major body systems, their primary organs, and their core physiological functions.

7.Describe the structural organization of the human body from cells to organ systems.

8.Explain the concept of homeostasis and identify negative feedback mechanisms.

9.Differentiate between anatomical position, directional terms, and body planes.

10.Correlate common medical conditions with the specific organ systems they affect.

11.Apply basic anatomical knowledge to routine clinical procedures (e.g., vital signs, patient positioning).

1.1 Structural Organization of the Body

The human body is organized hierarchically. Understanding this order is critical for interpreting medical terminology and pathology.

Chemical Level: Atoms combine to form molecules (e.g., water, proteins, DNA).

Cellular Level: Molecules form organelles and cells, the basic unit of life. Examples include muscle cells and nerve cells.

Tissue Level: Groups of similar cells performing a common function. There are four primary tissue types:

Epithelial: Covers body surfaces, lines cavities, forms glands (e.g., skin epidermis).

Connective: Supports and binds structures (e.g., bone, blood, cartilage, adipose).

Muscle: Facilitates movement (skeletal, cardiac, smooth).

Nervous: Transmits electrical impulses (neurons, neuroglia).

Organ Level: Two or more tissues working together (e.g., heart, liver, stomach).

Organ System Level: Organs that cooperate for a common function (e.g., digestive system).

Organismal Level: The sum of all systems working together.

Key Clinical Application: When you perform a venipuncture, you are accessing the cardiovascular system at the organ level (the vein), which is composed of epithelial (lining), connective (wall), and muscle (smooth) tissue.

1.2 Anatomical Position and Directional Terminology

Medical professionals use a universal reference point: the anatomical position (body erect, feet slightly apart, palms facing forward, thumbs pointing away from the body). All directional terms are relative to this position.

Critical Directional Terms (Memorize for the Exam):

Superior (cranial): Toward the head. The heart is superior to the stomach.

Inferior (caudal): Toward the feet. The stomach is inferior to the heart.

Anterior (ventral): Front of the body. The sternum is anterior to the heart.

Posterior (dorsal): Back of the body. The spine is posterior to the heart.

Medial: Closer to the midline. The ulna is medial to the radius.

Lateral: Farther from the midline. The thumb is lateral to the little finger.

Proximal: Closer to the point of attachment (trunk). The elbow is proximal to the wrist.

Distal: Farther from the point of attachment. The wrist is distal to the elbow.

Superficial: Toward the body surface. The skin is superficial to muscle.

Deep: Away from the body surface. Bone is deep to muscle.

Body Planes (Imaginary Lines):

Midsagittal (median) plane: Divides the body into equal left and right halves.

Frontal (coronal) plane: Divides the body into anterior and posterior sections.

Transverse (horizontal) plane: Divides the body into superior and inferior sections.

Body Cavities: The dorsal cavity protects the nervous system (cranial and vertebral cavities). The ventral cavity contains the thoracic cavity (heart, lungs) and abdominopelvic cavity (digestive, reproductive, urinary organs). The diaphragm separates the thoracic and abdominal cavities.

1.3 Homeostasis and Feedback Mechanisms

Homeostasis is the body's ability to maintain a stable internal environment (e.g., temperature at 98.6°F, blood pH at 7.35–7.45, blood glucose at 70–110 mg/dL). It is maintained through feedback loops.

Negative Feedback (Most Common): The response reverses the original stimulus, bringing the variable back to its set point.

Example: Body temperature rises → brain signals sweat glands to produce sweat → body cools → stimulus stops.

Clinical Example: Blood glucose rises after a meal → pancreas releases insulin → cells take up glucose → blood glucose falls.

Positive Feedback (Rare, Amplifying): The response enhances the original stimulus, pushing the variable further from the set point. It is often used for rapid, short-term processes.

Example: Childbirth (oxytocin increases contractions → more oxytocin released until birth).

Clinical Example: Blood clotting cascade (platelet plug formation activates more clotting factors).

Exam Trap: Students often confuse the two. Remember: Negative = reversal; Positive = amplification. Fever is a negative feedback mechanism resetting the set point, not a positive feedback loop.

1.4 Major Body Systems (Structure and Function)

You must know the primary organs and the main function of each system. The NHA exam tests application, not rote memorization of every bone.

1.4.1 Integumentary System

Organs: Skin (epidermis, dermis, hypodermis), hair, nails, sebaceous and sweat glands.

Functions: Protection (barrier against pathogens and dehydration), temperature regulation (sweating, vasodilation/vasoconstriction), sensation, vitamin D synthesis.

Clinical Relevance: Assess skin turgor for dehydration; note jaundice (liver issue) or cyanosis (oxygenation issue). Wound healing stages are tested.

1.4.2 Skeletal System

Organs: Bones, cartilage, ligaments, joints.

Functions: Support, protection (skull protects brain), movement (levers for muscles), mineral storage (calcium, phosphorus), hematopoiesis (blood cell production in red bone marrow).

Key Divisions: Axial skeleton (skull, vertebral column, rib cage) vs. Appendicular skeleton (limbs, pectoral and pelvic girdles).

Clinical Relevance: Fracture types (greenstick, comminuted, transverse). Osteoporosis is a loss of bone density.

1.4.3 Muscular System

Organs: Skeletal muscles (voluntary, striated), smooth muscles (involuntary, walls of hollow organs), cardiac muscle (involuntary, heart).

Functions: Movement, posture maintenance, heat production (shivering).

Key Terms: Origin (fixed attachment), insertion (moving attachment), flexion (decreasing angle), extension (increasing angle), abduction (moving away from midline), adduction (moving toward midline).

Clinical Relevance: Intramuscular (IM) injections are given in specific muscles: deltoid, vastus lateralis, ventrogluteal. Know the correct needle angle (90° for IM, 45° for subcutaneous, 15° for intradermal).

1.4.4 Nervous System

Organs: Brain, spinal cord, nerves, sensory receptors.

Divisions: Central Nervous System (CNS: brain + spinal cord) and Peripheral Nervous System (PNS: all nerves outside CNS). PNS is divided into somatic (voluntary) and autonomic (involuntary: sympathetic "fight or flight," parasympathetic "rest and digest").

Functions: Sensory input, integration, motor output; controls consciousness, memory, and cognition.

Clinical Relevance: Assessing level of consciousness (AVPU: Alert, Verbal, Pain, Unresponsive). Pupil response to light tests cranial nerve III.

1.4.5 Endocrine System

Organs: Pituitary, thyroid, parathyroid, adrenal glands, pancreas, ovaries, testes, pineal gland.

Functions: Hormone secretion for long-term regulation of metabolism, growth, reproduction, and blood glucose.

Key Hormones to Know:

Insulin (pancreas): Lowers blood glucose.

Glucagon (pancreas): Raises blood glucose.

Thyroxine (T4) / T3 (thyroid): Increases metabolic rate.

Cortisol (adrenal cortex): Stress hormone, raises blood glucose.

ADH (pituitary): Promotes water reabsorption in kidneys.

Clinical Relevance: Diabetes mellitus (Type 1: no insulin; Type 2: insulin resistance). Hypothyroidism vs. hyperthyroidism (weight gain/cold vs. weight loss/heat intolerance).

1.4.6 Cardiovascular System

Organs: Heart (4 chambers: right/left atria, right/left ventricles), blood vessels (arteries, veins, capillaries), blood.

Functions: Transport of oxygen, nutrients, hormones, and waste; thermoregulation; immunity (white blood cells).

Blood Flow Pathway (Memorize): Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs (gas exchange) → pulmonary veins → left atrium → mitral (bicuspid) valve → left ventricle → aortic valve → aorta → body.

Key Terms: Systole (contraction), diastole (relaxation). Pulse points: radial, carotid, brachial, femoral, popliteal, dorsalis pedis.

Clinical Relevance: Blood pressure is measured in mmHg. Normal adult BP is < 120/80 mmHg. Hypertension is ≥ 130/80 mmHg. Know the difference between arteries (carry blood away, high pressure, oxygenated except pulmonary) and veins (carry blood toward heart, low pressure, deoxygenated except pulmonary).

1.4.7 Respiratory System

Organs: Nose, pharynx, larynx, trachea, bronchi, bronchioles, alveoli, lungs.

Functions: Gas exchange (oxygen in, carbon dioxide out), regulation of blood pH, voice production.

Key Mechanics: Inspiration (diaphragm contracts, chest expands, pressure decreases) vs. Expiration (diaphragm relaxes, chest compresses, pressure increases).

Clinical Relevance: Normal adult respiratory rate is 12–20 breaths per minute. Pulse oximetry (SpO₂) normal is 95–100%. The primary stimulus for breathing is rising CO₂ levels, not low O₂.

1.4.8 Digestive System

Organs (GI Tract): Mouth, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (colon), rectum, anus.

Accessory Organs: Liver (produces bile), gallbladder (stores bile), pancreas (produces digestive enzymes and bicarbonate).

Functions: Ingestion, mechanical and chemical digestion, absorption (mostly in small intestine), elimination.

Clinical Relevance: The liver is the primary detoxification organ. The small intestine is the primary site of nutrient absorption. The large intestine absorbs water and electrolytes.

1.4.9 Urinary System

Organs: Kidneys (2), ureters (2), urinary bladder, urethra.

Functions: Filtration of blood, excretion of metabolic waste (urea, creatinine), regulation of fluid and electrolyte balance, blood pressure regulation (renin), and red blood cell production (erythropoietin).

Nephron: The functional unit of the kidney.

Clinical Relevance: Urinalysis is a common CCMA test. Normal urine is sterile, pale yellow. Ketones in urine indicate fat metabolism (diabetes or starvation). Protein in urine indicates kidney damage.

1.4.10 Lymphatic and Immune Systems

Organs: Lymph nodes, spleen, thymus, tonsils, lymphatic vessels, bone marrow.

Functions: Fluid balance (returns interstitial fluid to blood), fat absorption (lacteals), immunity (defense against pathogens).

Immunity Types: Innate (non-specific: skin, inflammation) vs. Adaptive (specific: B-cells producing antibodies, T-cells killing infected cells).

Clinical Relevance: Inflammation signs: redness, heat, swelling, pain, loss of function. The spleen filters blood and stores platelets.

1.4.11 Reproductive System

Male Organs: Testes (produce sperm and testosterone), epididymis, vas deferens, prostate, penis.

Female Organs: Ovaries (produce ova, estrogen, progesterone), fallopian tubes, uterus, vagina.

Functions: Gamete production, hormone secretion, fetal development (female).

Clinical Relevance: The menstrual cycle averages 28 days. Ovulation occurs around day 14. Pregnancy tests detect hCG (human chorionic gonadotropin).

1.5 Vital Signs and Anatomical Correlation

Vital signs are a direct reflection of the cardiovascular and respiratory systems. You must know the normal adult ranges:

Temperature: 97.8°F to 99.1°F (36.5°C to 37.3°C). Routes: Oral (most common), axillary (lowest, 1°F lower), rectal (most accurate, 1°F higher), tympanic, temporal.

Pulse (Heart Rate): 60–100 bpm (adult). Bradycardia < 60, Tachycardia > 100.

Respirations: 12–20 breaths/min. Note rhythm and depth (e.g., dyspnea = difficult breathing, apnea = no breathing).

Blood Pressure: Normal < 120/80 mmHg. Hypertension Stage 1: 130–139/80–89. Hypotension < 90/60.

Pulse Oximetry (SpO₂): 95–100%.

Clinical Application: When taking a blood pressure, the cuff is placed on the upper arm at heart level. The brachial artery is auscultated. The first Korotkoff sound = systolic; the disappearance of sound = diastolic.

1.6 Common Medical Terminology and Root Words

The NHA exam assumes you can break down medical terms.

Root: Core meaning (e.g., cardi = heart).

Prefix: Beginning (e.g., tachy- = fast, brady- = slow, hyper- = above, hypo- = below, dys- = painful/difficult).

Suffix: End (e.g., -itis = inflammation, -ectomy = surgical removal, -algia = pain, -emia = blood condition).

Examples:

Gastritis = inflammation of the stomach.

Hepatomegaly = enlarged liver.

Nephropathy = disease of the kidney.

1.7 Lifespan Considerations

Pediatric: Vital signs differ (higher heart rate, lower blood pressure). Fontanelles (soft spots) close by 18 months. The immune system is immature.

Geriatric: Decreased skin elasticity (risk for tears), decreased kidney function (affects drug excretion), decreased thermoregulation (risk for hypothermia), orthostatic hypotension (BP drops when standing).

Pregnancy: Increased blood volume (up to 40–50%), increased heart rate, increased respiratory rate, supine hypotensive syndrome (avoid positioning pregnant patients flat on their back in late term).

Common Exam Traps

144.Confusing Proximal vs. Distal: Students pick "proximal" for anything near the trunk, but forget it is relative. Trap: "The wrist is proximal to the elbow." Wrong — the wrist is distal to the elbow.

145.Mixing Anterior/Posterior: Trap: "The spine is anterior to the sternum." Wrong — the spine is posterior. Always visualize the anatomical position.

146.Positive vs. Negative Feedback: Trap: "Blood clotting is negative feedback." Wrong — it is positive (amplifying). Negative feedback reverses; positive feedback accelerates.

147.Artery vs. Vein Oxygenation: Trap: "All arteries carry oxygenated blood." Wrong — the pulmonary artery carries deoxygenated blood to the lungs. The pulmonary vein carries oxygenated blood to the heart.

148.Insulin vs. Glucagon: Trap: "Glucagon lowers blood sugar." Wrong — glucagon raises it. Insulin lowers it. Remember: "Insulin = In the cells."

149.Small vs. Large Intestine Absorption: Trap: "The large intestine absorbs nutrients." Wrong — the small intestine absorbs nutrients; the large intestine absorbs water and electrolytes.

150.Normal BP Range: Trap: "120/80 is hypertension." Wrong — it is normal (elevated, but not hypertensive). Hypertension Stage 1 starts at 130/80.

151.Primary Respiratory Stimulus: Trap: "Low oxygen drives breathing." Wrong — high carbon dioxide (CO₂) is the primary drive.

152.Axillary vs. Rectal Temperature: Trap: "Rectal is lower than oral." Wrong — rectal is higher (most accurate); axillary is lower.

153.Hematopoiesis Location: Trap: "The liver produces blood cells." Wrong — red bone marrow does. The liver produces bile.

Summary

Anatomy and physiology is the foundation of clinical practice. As a CCMA, you will apply this knowledge daily: taking vital signs (cardiovascular/respiratory), preparing patients for exams (positioning and planes), and understanding lab results (urinary/digestive systems). Focus on the function of each system, the relationship between systems (e.g., respiratory and cardiovascular for oxygenation), and the normal ranges for vital signs. Use the directional terms and body planes to communicate clearly with the care team. Master the feedback loops — they explain how the body maintains health and how diseases disrupt it.

Anatomy and Physiology