Advanced Medical Terminology - Body Systems & Word Parts

Body Directional Terms, Planes, Regions, and Positions

• Normal Anatomical Position:

  • Serves as the universal reference starting point for all anatomical descriptions.
  • Position criteria: The individual stands straight erect, eyes facing directly forward, arms hanging down by the sides, and palms of the hands facing forward.

• Planes of the Body:

  • Anatomical planes are imaginary 2D slices dividing the human body into distinct anatomical sections.     
  • Transverse Plane: Divides the body horizontally into top (superior) and bottom (inferior) portions.
  • Sagittal Plane: Divides the body vertically into right and left sides. All left and right designations refer strictly to the patient's left and right sides, not the clinical observer's.
    • Midsagittal Plane: A precise midline sagittal plane dividing the body into equal left and right halves.
    • Medial: Directional term defined as moving toward the midline of the body.
    • Lateral: Directional term defined as moving away from the midline of the body (e.g., the outer aspect of the knee).
    • Bilateral: Pertaining to two sides. Constructed from prefix bi- (two), combining form later/o (side), and suffix -al (pertaining to). Refers to structures present on both sides of the midline (e.g., arms, legs, eyes, kidneys, lungs).
    • Unilateral: Pertaining to one side. Constructed from prefix uni- (one), combining form later/o (side), and suffix -al (pertaining to).
  • Frontal (Coronal) Plane: Divides the body vertically into front and back sections.
    • Anterior (Ventral): Refers to the front side of the body. Combining form anter/o (front), suffix -ior (pertaining to).
    • Posterior (Dorsal): Refers to the back side of the body. Combining form poster/o (back), suffix -ior (pertaining to).
    • Posteroanterior (PA): Combined directional term denoting an X-ray beam path passing from the back through to the front of the body.
    • Anteroposterior (AP): Combined directional term denoting an X-ray beam path passing from the front through to the back of the body.

• Proximal and Distal Relationships:

  • Proximal: Directional term meaning toward the trunk of the body or point of attachment (e.g., the shoulder is proximal relative to the wrist).
  • Distal: Directional term meaning away from the trunk or point of attachment (e.g., the wrist is distal relative to the shoulder; toes are distal relative to the knee).
  • Superior: Directional term describing a structure located above another structure.
  • Inferior: Directional term describing a structure located below another structure.

• Abdominal Quadrants:

  • Four administrative quadrants dividing the abdominal and pelvic cavities, centered on the umbilicus (navel/belly button).
  • Left Upper Quadrant (LUQ): Patient's upper left abdominal area.
  • Left Lower Quadrant (LLQ): Patient's lower left abdominal area.
  • Right Lower Quadrant (RLQ): Patient's lower right abdominal area (e.g., site of acute appendicitis pain).
  • Right Upper Quadrant (RUQ): Patient's upper right abdominal area.

• Abdominal Regions ($3 \times 3$ Grid System):

  • Divides the anterior abdomen into nine anatomical regions organized like a tic-tac-toe grid centered on the umbilicus.     
  • Umbilical Region: The central square containing the umbilicus.
  • Right and Left Lumbar Regions: Regions flanking the umbilical region laterally on the right and left sides.
  • Epigastric Region: Region located directly superior to the umbilical region over the stomach (epi- = above/upon, gastr/o = stomach, -ic = pertaining to).
  • Hypogastric Region: Region located directly inferior to the umbilical region below the stomach (hypo- = below, gastr/o = stomach, -ic = pertaining to).
  • Right and Left Hypochondriac Regions: Upper lateral regions situated beneath the rib cartilage (hypo- = below, chondr/o = cartilage, -iac = pertaining to).
  • Right and Left Inguinal Regions: Lower lateral regions located in the groin area (inguin/o = groin, -al = pertaining to).

• Other Anatomical Regions:

  • Thoracic Region: Pertaining to the chest (thorac/o = chest, -ic = pertaining to). Divided internally from the abdominal cavity by the diaphragm muscle.
  • Axillary Region: Pertaining to the armpit (axill/o = armpit).
  • Gluteal Region: Pertaining to the buttock.

• Clinical Body Positions:

  • Supine Position: Patient lying flat on the back, face turned upward.
  • Prone Position: Patient lying flat on the abdomen, face turned downward.
  • Lateral Recumbent Position: Patient lying horizontally on his or her side.
  • Fowler's Position: Patient placed in an upright sitting position.
  • Trendelenburg Position: Patient lying supine on a tilted table with the feet elevated above the head; increases cerebral blood flow and treats clinical shock.
  • Lithotomy Position: Patient supine with upper torso flat, hips and knees flexed, legs raised and secured in stirrups, arms extended; utilized for gynecological, anal, and urological operative procedures.

• Word Parts Summary Table:

  • -al: pertaining to
  • anter/o: front
  • axill/o: armpit
  • bi-: two
  • chondr/o: cartilage
  • epi-: above, upon
  • gastr/o: stomach
  • hypo-: under, beneath, below
  • -iac: pertaining to
  • -ic: pertaining to
  • inguin/o: groin
  • -ior: pertaining to
  • later/o: side
  • poster/o: back
  • thorac/o: chest
  • uni-: one

Integumentary System

• Overview and Functions:

  • The skin is the largest organ system in the human body.
  • Combining forms meaning skin: cutane/o, derm/o, dermat/o.
  • Combining form meaning nail: onych/o.
  • Combining form meaning hair: trich/o.
  • Combining form meaning sweat: hidr/o.
  • Combining form meaning sebum or oil: seb/o.
  • Primary Protective Barrier: Intact skin prevents pathogenetic invasion (bacteria, viruses, fungi) and shields underlying structures from damaging solar ultraviolet (UV) radiation.
  • Sensory Perception: Cutaneous nerve receptors detect thermal stimuli (hot/cold), tactile touch, and noxious pain to prevent bodily trauma.
  • Thermoregulation: Deep dermal sweat glands act as a cooling apparatus; sweat evaporation off the cutaneous surface dissipates body heat and excretes cellular metabolic waste products.

• Anatomical Layers of the Skin:

  • Epidermis: The outermost waterproof epithelial layer containing melanin, the protective photopigment determining skin color (epi- = above/upon, dermis = skin).
  • Dermis: The thick structural middle skin layer (derm/o = skin, -is = pertaining to). Contains elastin fibers providing mechanical elasticity, cutaneous blood vessels, hair follicles, sweat glands, and sebaceous (oil) glands.
  • Subcutaneous Layer: The innermost layer composed of loose connective tissue and adipose fat (sub- = under, cutane/o = skin, -us = pertaining to). Insulates internal organs and conserves thermal body heat.

• Word Parts Summary Table:

  • cutane/o: skin
  • derm/o: skin
  • dermat/o: skin
  • hidr/o: sweat
  • onych/o: nail
  • seb/o: sebum or oil
  • trich/o: hair

Musculoskeletal System

• Overview and Functions:

  • Integrates the skeletal system (bones, joints, cartilage) and muscular system to establish structural framework, upright posture, visceral protection, movement, and physiological homeostasis.
  • Bone Count: Infant skeletons possess $300$ bones at birth; secondary osteological fusion reduces this total to $206$ adult bones.
  • Skeletal Functions: Structural support, erect stance, visceral shielding (cranium shields brain; ribs and sternum shield heart and lungs), hematopoiesis (blood cell synthesis in red bone marrow), mineral storage (calcium and phosphate reserves).
  • General Word Parts: oste/o (bone), arthr/o (joints), chondr/o (cartilage).

• Cranium and Facial Bones:

  • cran/o, crani/o: Cranium (cranial = pertaining to cranium; suffix -al).
  • lacrim/o: Tears. Lacrimal bones form the delicate inner wall of the orbit/eye socket (lacrim/o + -al).
  • maxill/o: Maxilla (upper jaw bone).
  • mandibul/o: Mandible (lower jaw bone).
  • zygomat/o: Zygomatic bones (cheekbones; zygomat/o + -ic = zygomatic).
  • nas/o: Nose. Nasal bones form the bridge of the nose (nas/o + -al = nasal).
  • Eight Cranial Bones: Frontal bone (forehead region); two Parietal bones (superior sides and posterior roof of cranium); two Temporal bones (inferior lateral walls located anterior/superior to ears); Occipital bone (posterior base of cranium); Sphenoid bone (butterfly-shaped internal bone anterior to temporal bones); Ethmoid bone (located between orbits at the roof of the nasal cavity).

• Vertebral Column (Spine):

  • Composed of $33$ individual and fused vertebrae protecting the spinal cord.
  • Combining forms for vertebrae/spine: spondyl/o, vertebr/o, rachi/o.
  • Cervical Vertebrae: $7$ neck vertebrae designated C1 through C7 (cervic/o = neck or cervix; cervical = pertaining to neck).
  • Thoracic Vertebrae: $12$ chest vertebrae designated T1 through T12 (thorac/o = chest; thoracic = pertaining to chest).
  • Lumbar Vertebrae: $5$ lower back vertebrae designated L1 through L5 (lumb/o = lower back; lumbar = pertaining to lower back).
  • Sacral Vertebrae (Sacrum): $5$ fused vertebrae designated S1 through S5 (sacr/o = sacrum). Warning Note: Do not confuse sacr/o (sacrum) with sarc/o (flesh/connective tissue).
  • Coccygeal Vertebrae (Coccyx): $4$ fused vertebrae forming the tailbone (coccyg/o = coccyx; suffix -eal = pertaining to; coccygeal = pertaining to coccyx).

• Thorax and Pelvis:

  • Thoracic Cage: Clavicles / collar bones (clavicul/o); Scapulae / shoulder blades (scapul/o); $12$ pairs of Ribs (cost/o); Sternum / breast bone (stern/o). Shields heart and lungs.
  • Pelvic Girdle: Pelvis (pelv/o) supports lower abdominal, urinary, and internal reproductive organs. Posterior pelvic arch formed by sacrum and coccyx.
  • Hip Bones (Innominator Bones): Composed of three fused regions:
    • Ilium: Superior flat pelvic bone (ili/o).
    • Ischium: Inferior posterior pelvic bone (ischi/o).
    • Pubis: Anterior inferior pelvic bone (pub/o). Left and right pubic bones join anteriorly at a fibrocartilage joint called the pubic symphysis.

• Extremities (Appendicular Skeleton):

  • Upper Extremity Bones:
    • Humerus: Single large upper arm bone (humer/o).
    • Radius: Lateral forearm bone situated on the thumb side (radi/o = radius, x-rays).
    • Ulna: Medial forearm bone situated on the little finger side (uln/o).
    • Carpals: $8$ short wrist bones (carp/o).
    • Metacarpals: Hand bones located beyond the wrist (metacarp/o; prefix meta- = beyond).
    • Phalanges: Digital bones of the fingers and toes (phalang/o).
  • Lower Extremity Bones:
    • Femur: Thigh bone (femor/o).
    • Tibia: Larger medial lower leg bone (tibi/o).
    • Fibula: Smaller lateral lower leg bone (fibul/o).
    • Patella: Kneecap (patell/o).
    • Knee Joint Structures: Menisci / Meniscus (menisc/o, crescentic cartilage plates); Bursa (burs/o, fluid-filled friction-reducing sacs); Synovium / Synovial Fluid (synovi/o, clear joint fluid lubricating articular interfaces).
    • Calcaneus: Heel bone (calcane/o).
    • Tarsals: $7$ ankle bones (tars/o). Human feet contain one-quarter ($25\%$) of all bones in the human body.
    • Metatarsals: Foot bones located beyond the tarsals.

• Muscular System:

  • Contains over $600$ individual muscles working in concert with bones to produce movement.
  • Combining forms: my/o, myos/o (muscle), kines/o, kinesi/o (movement).
  • Facial muscle dynamics: Requires $17$ muscles to smile and $43$ muscles to frown.
  • Skeletal (Voluntary) Muscle: Muscle under conscious neural control. Attached to bones by fibrous cords called tendons (ten/o, tend/o, tendin/o). Muscle shortening/contraction pulls tendons to move bones.
  • Smooth (Involuntary) Muscle: Non-striated muscle facilitating non-conscious visceral propulsion (e.g., intestinal peristalsis, vascular tone, pulmonary air regulation).
  • Cardiac Muscle: Specialized involuntary striated muscle forming the myocardium to drive cardiac pumping action.

• Word Parts Summary Table:

  • -al: pertaining to
  • -ar: pertaining to
  • arthr/o: joint
  • burs/o: bursa
  • calcane/o: calcaneus (heel bone)
  • carp/o: carpals (wrist bones)
  • cervic/o: neck, cervix
  • chondr/o: cartilage
  • clavicul/o: clavicle
  • coccyg/o: coccyx
  • cost/o: ribs
  • cran/o, crani/o: cranium
  • -eal: pertaining to
  • femor/o: femur
  • fibul/o: fibula
  • humer/o: humerus
  • -ic: pertaining to
  • ili/o: ilium
  • ischi/o: ischium
  • kinesi/o, kines/o: movement
  • lacrim/o: tears, eye socket
  • lumb/o: lower back, lumbar region
  • mandibul/o: mandible
  • maxill/o: maxilla
  • menisc/o: meniscus
  • metacarp/o: metacarpals
  • my/o, myos/o: muscle
  • nas/o: nose
  • oste/o: bone
  • patell/o: patella
  • pelv/o: pelvis
  • phalang/o: phalanges (fingers, toes)
  • pub/o: pubis
  • rachi/o: spine, vertebral column
  • radi/o: radius, x-rays
  • sacr/o: sacrum
  • scapul/o: scapula
  • spondyl/o: vertebra
  • stern/o: sternum
  • synovi/o: synovium, synovial fluid
  • tars/o: tarsals (ankle bones)
  • ten/o, tend/o, tendin/o: tendon
  • thorac/o: chest, thorax
  • tibi/o: tibia
  • uln/o: ulna
  • vertebr/o: vertebra
  • zygomat/o: zygomatic bone, cheek bone

Endocrine System

• Overview and Endocrine Glands:

  • Composed of ductless specialized glands secreting chemical messengers (hormones) directly into internal body fluids (end/o = within, crin/o = to secrete).
  • General combining form for gland: aden/o (e.g., adenopathy = gland disease; suffix -pathy).
  • Ovaries (ovari/o, oophor/o) and Testes (test/o, testicul/o): Gonadal glands secreting sex hormones regulating female and male reproductive systems.
  • Pancreas (pancreat/o): Situated posterior to the stomach. Regulates blood glucose levels (gluc/o, glyc/o, glycos/o = sugar/glucose) by releasing glucagon when blood sugar is low and insulin when blood sugar is elevated. Inhibits growth hormone secretion from the pituitary gland.
  • Adrenal Glands: Located on the superior pole of each kidney (ad- = towards, ren/o = kidney, -al = pertaining to). Secretion functions: regulate fluid/electrolyte balance (sodium/water), suppress tissue inflammation, drive sympathetic flight-or-fight response in danger, and secrete male sex hormones called androgens (andr/o = male, gen/o = formation/production).
  • Thymus Gland (thym/o): Situated in the anterior thoracic cavity; mediates immune system maturation.
  • Thyroid Gland (thyr/o): Located in the anterior neck; secretes metabolic hormones regulating basal metabolic rate.
  • Parathyroid Glands: Four small endocrine glands located alongside the lateral borders of the thyroid gland (para- = near/alongside, thyr/o = thyroid). Regulate systemic blood calcium levels (calc/i = calcium).
  • Pineal Gland (pineal/o): Located in the center of the brain; secretes melatonin to govern the internal circadian sleep-wake clock.
  • Pituitary Gland (pituitar/o): Located at the base of the brain; master gland regulating somatic growth, metabolism, blood pressure, gonad function, renal water balance, and thyroid activity.

• Word Parts Summary Table:

  • aden/o: gland
  • andr/o: male
  • calc/i: calcium
  • crin/o: to secrete
  • gen/o: to produce
  • gluc/o, glyc/o, glycos/o: sugar, glucose
  • oophor/o, ovari/o: ovary
  • pancreat/o: pancreas
  • para-: near, alongside
  • pineal/o: pineal gland
  • pituitar/o: pituitary gland
  • ren/o: kidney
  • test/o, testicul/o: testis or testicle
  • thym/o: thymus
  • thyr/o: thyroid

Nervous System

• Overview and Divisions:

  • Acts as the body's master electrical communication network consisting of the brain, spinal cord, and peripheral nerves.
  • Brain tissue composition: Approximately $80\%$ of total brain tissue volume is liquid. The brain exhibits greater neural activity during sleep than during wakefulness.
  • Central Nervous System (CNS): Comprises the brain and spinal cord. Serves as the central processing center for nerve impulses, consciousness, logical thought, personality, sensory perception, language processing, sleep-wake regulation, autonomic reflexes (cardiac rhythm, respiration), and voluntary motor execution.
  • Peripheral Nervous System (PNS): Comprises all cranial and peripheral nerves branching off the CNS to innervate organs and muscles.

• Anatomy of the Brain:

  • General brain combining form: encephal/o (prefix en- = within, combining form cephal/o = head). Enclosed within the cranium (cran/i, crani/o).
  • Cerebrum (cerebr/o): The largest region of the brain, divided into left and right hemispheres.     
  • Four Cerebral Lobes: Frontal lobe (anterior; reasoning, motor planning, personality); Parietal lobe (superior; somatosensory processing); Temporal lobe (lateral; auditory and language processing); Occipital lobe (posterior; visual impulse interpretation).
  • Cerebellum (cerebell/o): Located inferior/posterior to the cerebrum. Coordinates voluntary muscular activity, posture, and balance.
  • Thalamus (thalam/o = inner chamber): Central relay station routing motor/sensory signals to the cerebral cortex; regulates consciousness and sleep.
  • Hypothalamus (hypo- = below): Situated inferior to the thalamus. Controls visceral homeostatic drivers including hunger, thirst, and body temperature.
  • Brain Stem: Composed of the Pons (relay bridge between cerebrum and cerebellum; regulates breathing and sleep) and the Medulla Oblongata (inferior stem connecting pons to spinal cord; controls vital autonomic cardiovascular/respiratory centers).

• Meninges, Spinal Cord, and Peripheral Nervous System:

  • Meninges (mening/o): Three protective membrane layers encapsulating the brain and spinal cord:
    • Dura Mater (dur/o = hard): Tough, fibrous outermost meningeal layer.
    • Arachnoid (arachn/o = spider): Web-like middle meningeal layer.
    • Pia Mater: Delicate vascular innermost layer adhering to brain surfaces.
  • Spinal Cord (myel/o = spinal cord or bone marrow; spin/o = spine): Continuous tubule of neural tissue extending from the medulla oblongata to the L1-L2 intervertebral space. Routes motor and sensory nerve impulses; mediates spinal reflexes. Spinal nerve roots (radicul/o, radic/o).
  • Nerves and Glia: Neurons (neur/o) conduct electrical signals. Glial cells (gli/o = glue) provide structural support, form protective myelin sheaths, and maintain cellular homeostasis.
  • Ganglia (gangli/o, ganglion/o = knot or swelling): Nodular swelling-like collections of nerve cell bodies serving as impulse transmission junctions throughout the PNS.

• Word Parts Summary Table:

  • arachn/o: spider
  • cephal/o: head
  • cerebell/o: cerebellum
  • cerebr/o: cerebrum
  • cran/i, crani/o: cranium
  • dur/o: hard, dura mater
  • en-: within
  • encephal/o: brain
  • gangli/o, ganglion/o: ganglion, knot or swelling
  • gli/o: glue, glial cells
  • hypo-: below
  • mening/o: meninges
  • myel/o: spinal cord, bone marrow
  • neur/o: nerve
  • radic/o, radicul/o: nerve root
  • spin/o: spine
  • thalam/o: thalamus

Special Senses: Eyes

• Anatomy of the Eye:

  • Iris (irid/o, ir/o): Pigmented anterior muscular ring controlling pupil aperture size.
  • Pupil (pupill/o, cor/o, core/o): Central aperture in the iris through which light enters. Warning Note: Do not confuse cor/o/core/o (pupil) with coron/o (heart) or corne/o (cornea).
  • Sclera (scler/o): Dense white outer fibrous coat of the eye. Contextual Note: scler/o means sclera in ocular terms, but means hard in non-ocular medical contexts.
  • Eyelids (blephar/o, palpebr/o): Protective muscle-skin folds that protect and moisten the ocular surface.
  • Conjunctiva (conjunctiv/o): Transparent mucous membrane covering exposed ocular surfaces.
  • Lacrimal Apparatus (lacrim/o): Tears produced by lacrimal glands located in the superior outer orbital corner; drain through lacrimal ducts located at the inferior medial eyelid margin. Neonates emit crying sounds at birth but do not synthesize fluid tears until $4\text{--}13$ weeks of age.

• Physiology of Vision:

  • Refracted light (phot/o) enters through the Cornea (corne/o, clear anterior outer layer), passes through the central Pupil (size regulated by Iris muscles), and strikes the Lens (phac/o, phak/o).
  • The lens dynamically changes shape to focus light rays onto the Retina (retin/o) lining the posterior wall.
  • Retinal Photoreceptors: Cones located in the Macula (macul/o) mediate high-acuity color vision in bright light. Rods located outside the macula mediate peripheral, motion, and night vision.
  • Inverted Visual Image: Light rays projected onto the retina produce an upside-down inverted image; image inversion is corrected right-side up when processed in the cerebral visual cortex via the Optic Nerve (opt/o = eye, -ic = pertaining to).

• Ocular Cavities and Fluid Chambers:

  • Anterior Cavity: Contains the Anterior Chamber (between inner cornea and iris) and Posterior Chamber (behind iris, in front of lens). Both filled with circulating Aqueous Humor supplying nutrients and oxygen.
  • Posterior Cavity: Large space situated between lens and retina containing gel-like Vitreous Humor (vitr/o = vitreous body, vitre/o = glass) maintaining structural eye shape.

• Word Parts Summary Table:

  • blephar/o, palpebr/o: eyelid
  • conjunctiv/o: conjunctiva
  • cor/o, core/o, pupil/o: pupil
  • corne/o: cornea
  • ir/o, irid/o: iris
  • lacrim/o: tears, lacrimal structures
  • macul/o: macula
  • ocul/o, opt/o: eye
  • phac/o, phak/o: lens
  • phot/o: light
  • retin/o: retina
  • scler/o: sclera, hard
  • vitr/o: vitreous body
  • vitre/o: glass

Special Senses: Ears

• Anatomy and Hearing Pathway:

  • General combining forms for ear: aur/o, auricul/o, ot/o.
  • Combining forms/suffixes for hearing: audi/o, audit/o, acous/o, acoust/o, -acusis, -cusis.
  • External Ear: Composed of the Auricle / Pinna (outer cartilaginous shell gathering ambient sound waves) and the Auditory Canal / Ear Canal. Glands in the canal synthesize Cerumen / earwax (cerumen/o) to trap debris.
  • Middle Ear: Sound waves strike and vibrate the Tympanic Membrane / Eardrum (tympan/o, myring/o). Vibrations propagate sequentially across three auditory ossicles: Malleus (hammer) $\rightarrow$ Incus (anvil) $\rightarrow$ Stapes (staped/o, stirrup).
  • Inner Ear: The footplate of the stapes vibrates against the Cochlea (cochle/o = snail, spiral fluid-filled chamber). Fluid displacement bends microscopic sensory hair cells, generating electrical nerve impulses transmitted along the auditory nerve to the brain.
  • Equilibrium and Pressure Equalization: The inner ear Labyrinth (labyrinth/o = maze) houses the Semicircular Canals and Vestibule, which detect spatial motion to maintain balance. The Eustachian Tube connects the middle ear cavity to the nasopharynx to drain fluid and equalize middle ear pressure.

• Word Parts Summary Table:

  • acous/o, acoust/o, audi/o, audit/o, -acusis, -cusis: hearing
  • aur/o, auricul/o, ot/o: ear
  • cerumen/o: cerumen (earwax)
  • cochle/o: cochlea
  • labyrinth/o: maze, inner ear labyrinth
  • myring/o, tympan/o: eardrum, tympanic membrane
  • staped/o: stapes

Digestive System

• Overview and Upper GI Tract:

  • Also designated the gastrointestinal (GI) system. Functions to ingest food, digest macromolecules, absorb nutrients, and excrete unabsorbed waste.
  • Combining form for digestion: pept/o; suffix: -pepsia.
  • Oral Cavity / Mouth (or/o, stomat/o): Mastication (chewing) physically degrades food. Salivary glands secrete Saliva (sial/o; daily volume = $1\text{--}3$ pints) containing digestive enzymes.
  • Oral Structures: Lips (cheil/o); Teeth (dent/i); Gums (gingiv/o); Tongue (gloss/o, lingu/o); Palate / roof of mouth (palat/o); Uvula / tissue hanging in central posterior throat (uvul/o); Pharynx / throat (pharyng/o).     
  • Esophagus (esophag/o): Muscular tube propelling food down to the stomach via involuntary wave-like muscular contractions called peristalsis.
  • Stomach (gastr/o): Adult volumetric holding capacity is approximately $1.5\,\text{liters}$. Hydrochloric acid and gastric enzymes break food down into chyme. The distal region is the Pylorus (pylor/o = gatekeeper), containing the pyloric sphincter valve regulating chyme entry into the small intestine.

• Small Intestine, Large Intestine, and Accessory Organs:

  • Small Intestine (enter/o): Primary site of nutrient absorption. Divided into three segments: Duodenum (duoden/o, first section; Upper GI tract = esophagus, stomach, duodenum), Jejunum (jejun/o, middle section), and Ileum (ile/o, terminal section). Warning Note: Do not confuse ile/o (ileum) with ili/o (iliac bone).     
  • Large Intestine (Bowel): Formed waste is termed feces or stool. Segments:
    • Cecum (cec/o): Proximal pouch receiving chyme. Worm-like Appendix (appendic/o) hangs off the cecum; inflammation causes appendicitis.
    • Colon (col/o, colon/o): Houses over $400$ distinct bacterial species. Four divisions: Ascending Colon (travels upward), Transverse Colon (trans- = across/through, travels horizontally across abdomen), Descending Colon (travels downward), and Sigmoid Colon (sigmoid/o, S-shaped curve).
    • Rectum (rect/o) and Anus (an/o): Terminal storage and elimination canal (proct/o = rectum and anus).
  • Accessory Digestive Organs:
    • Liver (hepat/o): Synthesizes green Bile (chol/e, gall) to digest lipids.
    • Gallbladder (cholecyst/o from chol/e + cyst/o = bladder): Stores and concentrates bile. Contracts to discharge bile through the Common Bile Duct (choledoch/o) into the duodenum.
    • Pancreas (pancreat/o): Excretes digestive enzyme juices into the duodenum.

• Word Parts Summary Table:

  • an/o: anus
  • appendic/o: appendix
  • cec/o: cecum
  • cheil/o: lips
  • chol/e: bile, gall
  • cholecyst/o: gallbladder
  • choledoch/o: common bile duct
  • col/o, colon/o: colon
  • cyst/o: bladder
  • dent/i: teeth
  • duoden/o: duodenum
  • enter/o: intestines, small intestine
  • esophag/o: esophagus
  • gastr/o: stomach
  • gingiv/o: gums
  • gloss/o, lingu/o: tongue
  • hepat/o: liver
  • ile/o: ileum
  • jejun/o: jejunum
  • or/o, stomat/o: mouth
  • palat/o: palate
  • pancreat/o: pancreas
  • -pepsia, pept/o: digestion
  • pharyng/o: pharynx
  • proct/o: rectum and anus
  • pylor/o: pylorus, gatekeeper
  • rect/o: rectum
  • sial/o: saliva
  • sigmoid/o: sigmoid colon
  • trans-: across, through
  • uvul/o: uvula

Respiratory System

• Overview and Functional Purpose:

  • Facilitates respiration by moving atmospheric air into and out of the lungs.
  • Normal resting adult respiratory rate: $12\text{--}15$ breaths per minute.
  • Combining forms for breathing: spir/o; suffix: -pnea.
  • Combining form for oxygen: ox/i (abbreviated $O_2$).
  • Gas Exchange Mechanism: Inspiration (inhalation) moves $O_2$ into pulmonary alveoli where it diffuses into capillary blood. Systemic cells produce Carbon Dioxide ($CO_2$) waste, transported via blood back to alveoli to be exhaled during expiration (exhalation).

• Upper Airway:

  • Nasal Cavity (nas/o, rhin/o): Inhaled air is warmed, cleansed by nasal hairs, and humidified. Divided by the osteocartilaginous Nasal Septum (sept/o = wall/partition).
  • Pharynx (pharyng/o): Divided into Nasopharynx (posterior to nasal cavity), Oropharynx (posterior to oral cavity), and Laryngopharynx (inferior segment connecting to larynx and esophagus).
  • Epiglottis (epiglott/o; epi- = above/upon, glott/o = opening to glottis): Cartilaginous flap superior to larynx that folds down during swallowing to prevent food aspiration into the trachea.
  • Larynx (laryng/o): Voice box containing vocal cords, connecting laryngopharynx to trachea.

• Lower Airway and Accessory Respiratory Structures:

  • Trachea (trache/o): Windpipe conducting air down into the thoracic cavity.
  • Bronchi (bronch/i, bronch/o): Left and right primary bronchial tubes branching off the trachea into each lung. Branch smaller into Bronchioles.
  • Alveoli (alveol/o): Microscopic terminal air sacs enveloped by capillaries where gas exchange occurs.
  • Lungs (pneum/o, pneumon/o, pneumat/o, pulmon/o, lob/o = lobe): Primary respiratory organs. Right lung is slightly larger and contains $3$ lobes; left lung contains $2$ lobes.
  • Intercostal Muscles: Muscles situated between ribs (inter- = between, cost/o = ribs, -al = pertaining to).
  • Diaphragm (phren/o): Muscular partition inferior to ribs driving pulmonary ventilation.
  • Pleura (pleur/o): Double-layered serous membrane encapsulating lungs and lining the thoracic cavity.

• Word Parts Summary Table:

  • alveol/o: alveolus, air sac
  • atel/o: incomplete
  • bronch/i, bronch/o: bronchus
  • cost/o: ribs
  • -eal: pertaining to
  • epiglott/o: epiglottis
  • glott/o: glottis opening
  • inter-: between
  • laryng/o: larynx
  • lob/o: lobe
  • nas/o, rhin/o: nose
  • or/o: mouth
  • ox/i: oxygen
  • pharyng/o: pharynx
  • phren/o: diaphragm
  • pleur/o: pleura
  • -pnea: breathing
  • pneum/o, pneumon/o, pneumat/o, pulmon/o: lung or air
  • sept/o: wall or partition (nasal septum)
  • spir/o: breathe
  • trache/o: trachea

Blood and Lymphatic System

• Blood Composition and Hematopoiesis:

  • Total adult blood volume is approximately $10\,\text{pints}$; a newborn baby has approximately $1\,\text{cup}$ of blood.
  • Blood combining forms: hem/o, hemat/o.
  • Hematopoiesis: Synthesis of blood cells occurring in red bone marrow (hemat/o = blood, -poiesis = formation).     
  • Red Blood Cells (Erythrocytes / RBCs): Red blood cells (erythr/o = red, cyt/o = cell). Contain hemoglobin to transport oxygen and carbon dioxide. Circulate in blood for approximately $120$ days.
  • White Blood Cells (Leukocytes / WBCs): Immune defense cells (leuk/o = white, cyt/o = cell). Synthesize antibodies and eliminate pathogens via Phagocytosis (phag/o = to eat, cyt/o = cell, -osis = condition of). Five primary WBC types: Monocytes, Eosinophils, Lymphocytes, Neutrophils, Basophils.
  • Platelets (Thrombocytes): Clotting blood cells (thromb/o = clot, cyt/o = cell). Aggregate and release coagulation factors to form blood clots.
  • Plasma: Clear yellowish fluid portion constituting $55\%$ of total blood volume.

• Spleen and Lymphatic System:

  • Spleen (splen/o): Vascular lymphoid organ located in the LUQ containing over $1\,\text{pint}$ of blood. Destroys aged erythrocytes and filters pathogens via dense lymphocyte clusters.
  • Lymphatic System: System of vessels and nodes transporting Lymph (lymph/o). Lymph nodes filter lymph fluid; localized lymph node swelling indicates active infection.
  • Pathogen: Any disease-producing microorganism (path/o = disease, -gen = substance that produces).
  • Thymus Gland (thym/o): Thoracic lymphatic organ mediating T-cell lymphocyte maturation.
  • Tonsils (tonsill/o): Lymphoid tissue masses protecting against inhaled/ingested pathogens. Three sets: Palatine tonsils (located in throat), Adenoids / Pharyngeal tonsils (aden/o = gland, -oid = resembling; located in nasopharynx), and Lingual tonsils (located at the base of the tongue).

• Word Parts Summary Table:

  • aden/o: gland
  • cyt/o: cell (Warning: Do not confuse cyt/o [cell] with cyst/o [bladder/sac])
  • erythr/o: red
  • -gen: substance that produces
  • hem/o, hemat/o: blood
  • leuk/o: white
  • lymph/o: lymph
  • -oid: resembling, derived from
  • -osis: condition of
  • path/o: disease
  • phag/o: eat
  • -poiesis: formation
  • splen/o: spleen
  • thromb/o: clot
  • thym/o: thymus
  • tonsill/o: tonsil

Cardiovascular System

• Overview and Cardiac Anatomy:

  • System circulating blood throughout body tissues (cardi/o = heart, vascul/o = blood vessel, -ar = pertaining to).
  • Four Heart Chambers:
    • Atria (atri/o): Right and left superior receiving chambers.
    • Ventricles (ventricul/o): Right and left inferior pumping chambers.
  • Four Heart Valves:
    • Tricuspid Valve: Located between right atrium and right ventricle.
    • Pulmonary Valve: Located between right ventricle and pulmonary artery.
    • Mitral Valve (mitr/o): Bicuspid valve located between left atrium and left ventricle.
    • Aortic Valve (aort/o): Located between left ventricle and the aorta.

• Blood Circulation Path and Vessels:

  • Systemic Circulation Flow: Deoxygenated blood returns from systemic tissues via Superior and Inferior Vena Cava $\\rightarrow$ Right Atrium $\\rightarrow$ Tricuspid Valve $\\rightarrow$ Right Ventricle $\\rightarrow$ Pulmonary Valve $\\rightarrow$ Pulmonary Artery (pulmon/o = lung; the pulmonary artery is the only artery carrying deoxygenated blood) $\\rightarrow$ Lungs ($O_2$ absorption) $\\rightarrow$ Pulmonary Veins $\\rightarrow$ Left Atrium $\\rightarrow$ Mitral Valve $\\rightarrow$ Left Ventricle $\\rightarrow$ Aortic Valve $\\rightarrow$ Aorta (aort/o; largest artery, ~$1\,\text{inch}$ diameter) $\\rightarrow$ Systemic Arteries.
  • Coronary Arteries (coron/o = heart, -ary = pertaining to): Arteries branching off the aorta to supply oxygenated blood directly to the myocardium. Occlusion causes myocardial infarction (heart attack).
  • Vascular Tree (angi/o, vascul/o):
    • Arteries (arteri/o, arter/o): Vessels carrying blood away from the heart. Key examples: Carotid arteries (neck/brain supply); Brachial arteries (brachi/o = arm; site for blood pressure cuff auscultation); Radial arteries (wrist thumb-side; site for pulse palpation); Femoral arteries (thigh/leg supply).
    • Arterioles (arteriol/o): Smallest arterial branches.
    • Capillaries: Microscopic single-cell vessels mediating capillary gas, nutrient, and waste exchange with tissues.
    • Venules (venul/o): Smallest venous vessels.
    • Veins (ven/o, ven/i, phleb/o): Vessels returning deoxygenated blood back toward the heart.

• Cardiac Conduction System:

  • Intrinsic neuromuscular tissue governing cardiac contraction rate and rhythm.
  • Sinoatrial Node (SA Node): Primary cardiac pacemaker located in the right atrium; generates electrical impulses.
  • Atrioventricular Node (AV Node): Delays impulse conduction between atria and ventricles.
  • Bundle of His (Atrioventricular Bundle): Specialized conduction fibers conducting impulses down the septum into ventricular walls to trigger ventricular contraction.

• Word Parts Summary Table:

  • angi/o, vascul/o: vessel, blood vessel
  • aort/o: aorta
  • -ar, -ary: pertaining to
  • arter/o, arteri/o: artery
  • arteriol/o: arteriole
  • atri/o: atrium
  • brachi/o: arm
  • cardi/o, coron/o: heart
  • mitr/o: mitral valve
  • phleb/o, ven/i, ven/o: vein
  • pulmon/o: lung
  • ventricul/o: ventricle
  • venul/o: venule

Urinary System

• Overview and Kidney Functions:

  • Also termed the renal system. Functions to excrete nitrogenous waste, regulate blood pressure, and maintain fluid, electrolyte, and acid-base homeostasis.
  • Urination clinical terms: Micturition and Voiding.
  • Urine combining forms: urin/o, ur/o, urin/a; suffixes: -uresis, -uria.
  • Normal adult daily urine output: Approximately $1.5\,\text{liters}$ per day.     
  • Kidneys (ren/o, nephr/o): Retroperitoneal organs (retro- = back/behind, peritone/o = peritoneum cavity membrane, -eal = pertaining to). Kidneys filter total systemic blood volume approximately $60$ times per day.
  • Internal Renal Structures: Glomerulus (glomerul/o, capillary filtration network); Renal Pelvis (pyel/o, funnel collecting urine into ureter).
  • Key Renal Functions: Filters blood and excretes urea (yellow nitrogenous byproduct); regulates blood glucose by excreting excess glucose into urine; manages electrolytes (sodium, potassium, chloride, bicarbonate) and hydrogen ions to maintain acid-base balance; excretes drug metabolites; regulates blood pressure by releasing the enzyme Renin.

• Urinary Tract Structures:

  • Ureters (ureter/o): Muscular tubes conveying urine from renal pelvis down to bladder. Warning Note: Do not confuse ureter/o (ureter) with urethr/o (urethra).
  • Urinary Bladder (cyst/o, vesic/o): Collapsible muscular sac storing urine.
  • Urethra (urethr/o): Terminal canal conveying urine from bladder to the external environment. Females have a significantly shorter urethra than males, predisposing females to higher rates of urinary tract infections (UTIs).
  • Urinary Meatus (meat/o): External urethral opening.

• Word Parts Summary Table:

  • cyst/o, vesic/o: bladder
  • -eal: pertaining to
  • glomerul/o: glomerulus
  • meat/o: meatus
  • nephr/o, ren/o: kidney
  • peritone/o: peritoneum
  • pyel/o: renal pelvis
  • retro-: back or behind
  • ur/o, urin/o, urin/a: urine, urinary tract
  • ureter/o: ureter
  • urethr/o: urethra
  • -uresis: urination
  • -uria: condition of urine, urination

Male Reproductive System

• Functions and Anatomy:

  • Physiological Functions: Produce male sex hormone (testosterone), synthesize sperm and protective seminal fluid (semen), and discharge sperm into the female reproductive tract.     
  • Scrotum: External cutaneous sac enclosing testes/epididymis; maintains testicular temperature slightly lower than body temperature for sperm viability.
  • Testes / Testicles (test/o, testicul/o, orch/o, orchi/o, orchid/o): Primary gonads synthesizing testosterone and producing sperm within seminiferous tubules.
  • Epididymis (epididym/o): Coiled tubule along testicle collecting and maturing sperm.
  • Vas Deferens (vas/o = vessel or duct): Excretory duct conveying sperm from epididymis toward urethra. Surgical bilateral transection of vas deferens is termed a Vasectomy.
  • Seminal Vesicles (semin/o = semen or seed): Glands secreting nutrient-rich fluid forming semen.
  • Prostate Gland (prostat/o): Encircles upper urethra; secretes alkaline fluid protecting sperm from female vaginal acidity.
  • Bulbourethral Glands (Cowper Glands): Paired glands secreting protective fluid into semen.
  • Urethra (urethr/o): Dual-function canal conveying urine from bladder and semen during ejaculation.
  • Penis (phall/o, pen/o): Male copulatory organ. Average erect American penis length is $5.6\,\text{inches}$. Glans Penis / distal tip (balan/o).

• Word Parts Summary Table:

  • balan/o: glans penis
  • epididym/o: epididymis
  • orch/o, orchi/o, orchid/o, test/o, testicul/o: testes or testicle
  • pen/o, phall/o: penis
  • prostat/o: prostate
  • semin/o: semen, seed
  • urethr/o: urethra
  • vas/o: vessel, duct, vas deferens

Female Reproductive System

• Genitalia and Internal Structures:

  • Genitalia combining form: genit/o (reproductive organs).     
  • Ovaries (ovari/o, oophor/o): Paired pelvic gonads producing ova/eggs (ovum lifespan = $12\text{--}24\,\text{hours}$) and hormones (estrogen and progesterone).
  • Fallopian Tubes / Uterine Tubes (salping/o, -salpinx): Tubes conveying released ova from ovaries to uterus. Fertilization usually occurs in the fallopian tube.
  • Uterus (hyster/o, uter/o, metr/o, metri/o): Hollow muscular organ accommodating fetal development. Three wall layers:
    • Perimetrium: Outer membrane (peri- = around, metr/o = uterus, -ium = structure).
    • Myometrium: Middle muscular layer contracting during labor (my/o = muscle).
    • Endometrium: Inner vascular mucosa shed during menstruation (endo- = in/within).
  • Cervix (cervic/o): Lower muscular neck of uterus opening into vagina. Context Note: cervic/o refers to cervical spine or uterine cervix depending on context.
  • Vagina (colp/o, vagin/o): Muscular birth canal and menstrual outlet.

• External Genitalia (Vulva):

  • Vulva (vulv/o): External genitalia comprising labia majora and minora (labi/o = lip), urethral meatus, and clitoris.
  • Perineum (perine/o): Region located between the vulva and anus (an/o).

• Word Parts Summary Table:

  • an/o: anus
  • cervic/o: cervix or neck
  • colp/o, vagin/o: vagina
  • endo-: in, within
  • genit/o: genitalia
  • hyster/o, metr/o, metri/o, uter/o: uterus
  • -ium: structure or tissue
  • labi/o: lip (labia)
  • my/o: muscle
  • oophor/o, ovari/o: ovary
  • peri-: around
  • perine/o: perineum
  • salping/o, -salpinx: fallopian tube
  • vulv/o: vulva

Obstetrics and Human Reproduction

• Obstetrics and Menstrual Cycle:

  • Obstetrics (obstetr/o = pregnancy/birth, -ic = pertaining to): Medical specialty caring for mothers through pregnancy, labor, delivery, and the postpartum period ($6\,\text{weeks}$ post-delivery).
  • Menstruation (men/o = menstruation/menses): Occurs approximately every $28$ days if fertilization does not occur.
  • Menarche (-arche = beginning): First menstrual period at puberty (men/o + -arche).
  • Menstrual Cycle Phases:
    • Follicular Phase: Days $1\text{--}14$ (Day $1$ = onset of menses); ovarian follicle matures, endometrium thickens.
    • Ovulation Phase: ~Day $14$ (lasts $16\text{--}32\,\text{hours}$); mature egg released (o/o, ov/o, ovul/o = egg; -ation = process/condition).
    • Luteal Phase: Phase following ovulation up to onset of next menses.

• Pregnancy and Fetal Development:

  • Conception occurs ~$2\,\text{weeks}$ post last menstrual period (LMP). Egg fertilization by sperm forms a Zygote ($46$ chromosomes).
  • Embryo (embry/o): Gestational term from week $3$ through week $8$.
  • Fetus (fet/o): Gestational term from week $9$ through birth. Full-term pregnancy = $40\,\text{weeks}$ ($280\,\text{days}$).
  • Gestational Membranes:
    • Amniotic Sac / Amnion (amni/o): Inner membrane containing amniotic fluid encapsulating fetus.
    • Chorion (chorion/o): Outer membrane forming the placenta.
    • Placenta: Vascular organ attached to uterine wall providing oxygen, nutrients, and waste exchange.
    • Umbilical Cord: Connects fetus to placenta; attached at the Umbilicus / navel (umbilic/o, omphal/o).

• Clinical Obstetrical Definitions:

  • Gravida (Gravidity): Total number of times a woman has been pregnant.
  • Para (Parity; -para = to bear/bring forth): Total number of births carried past $20\,\text{weeks}$ gestational age.
    • Nullipara (nulli- = none): Woman who has zero births past $20\,\text{weeks}$ gestation.
    • Primipara (primi- = first): Woman who has delivered her first child past $20\,\text{weeks}$ gestation.
    • Multipara (multi- = many): Woman who has delivered two or more children past $20\,\text{weeks}$ gestation.
  • Prenatal Period: Time from conception to onset of labor (pre- = before, nat/i = birth, -al = pertaining to).
  • Labor and Parturition: Forceful uterine contractions driving delivery. Childbirth is termed Parturition.
  • Postpartum Period: Period extending from delivery through $6\,\text{weeks}$ (post- = after, -partum = birth/labor).
  • Mammary Glands / Breasts (mamm/o, mast/o, -ary = pertaining to): Integumentary glands that secrete milk to nourish infants post-birth.

• Word Parts Summary Table:

  • -al, -ary, -ic: pertaining to
  • amni/o: amnion, amniotic sac
  • -arche: beginning
  • -ation: process, condition
  • chorion/o: chorion
  • embry/o: embryo
  • fet/o: fetus
  • mamm/o, mast/o: breasts
  • men/o: menstruation, menses
  • multi-: many
  • nat/i: birth
  • nulli-: none
  • o/o, ov/o, ovul/o: egg
  • obstetr/o: pregnancy, birth
  • omphal/o, umbilic/o: umbilicus (navel)
  • -para: to bear, to bring forth
  • -partum: birth, labor
  • post-: after
  • pre-: before, in front of
  • primi-: first