ATI TEAS Comprehensive A&P Video Lecture – Key Vocabulary

Burns: Classification & Clinical Significance

• Four depth levels

  • 1st-degree: only epidermis ➜ red, painful, heals quickly.

  • 2nd-degree: epidermis + upper dermis ➜ blisters, very painful.

  • 3rd-degree: full epidermis & dermis ➜ appears leathery/charred; often less painful because sensory nerves destroyed.

  • 4th-degree: extends into sub-cutaneous tissues, muscle, bone.

• Threats from extensive burns

  • Loss of skin’s fluid-retention barrier ➜ shock.

  • Loss of protective barrier ➜ high infection risk.

Endocrine System: Organs & Locations

• Brain: hypothalamus, pineal, pituitary.

• Neck: thyroid, 4 parathyroid glands.

• Chest: thymus (prominent in children, shrinks after puberty).

• Abdomen: adrenal glands (atop kidneys), pancreas (LUQ), stomach (gastrin-secreting G-cells).

• Pelvis: gonads → ovaries/testes.

Endocrine vs Exocrine

• Endocrine = duct-less; hormones ENter bloodstream.

• Exocrine = ducts; secretions EXit to surface/cavities (e.g.
  sweat, mammary, digestive enzymes).

• Dual-role example: pancreas ➜ insulin/glucagon (endocrine) + digestive enzymes (exocrine).

Hormone Chemistry & Action

• Built from amino acids (mono-amines, peptides, polypeptides) or lipids (steroids).

• Shape dictates receptor location & action (membrane vs intracellular) ➜ triggers mitosis, enzyme activation, etc.

Hypothalamus–Pituitary Axis

Posterior Pituitary (stores hypothalamic hormones)

• Oxytocin → uterine contraction, milk ejection.

• ADH (vasopressin) → kidney water re-absorption.

  • Mnemonic: Anti-Diuresis = “can’t pee”.

Anterior Pituitary (makes its own hormones)

Pineal Gland

• Secretes melatonin → regulates circadian rhythm / sleep–wake cycle.

Thyroid & Parathyroids: Calcium & Metabolism

• Thyroid hormones T₄ & T₃ (contain 4 and 3 iodine atoms) → “turn up” metabolic rate.

• Calcitonin – "Calci-tonin-down" ➜ lowers blood Ca^{2+}.

• Parathyroid hormone (PTH) – "Parathyroid Pushes it Up" ➜ raises blood Ca^{2+} for nerve, muscle, clotting, enzyme actions.

Thymus

• Produces thymosin → "Thymosin Must Stimulate immunity" ➜ drives T-cell maturation.

Adrenal Glands

• Medulla: Epinephrine (heart) & Norepinephrine (vessels) → fight/flight.

  • Mnemonic: "Epi-No rush".

• Cortex:

  • Glucocorticoid: cortisol – “Controls stress”; ↑ blood glucose, anti-inflammatory.

  • Mineralocorticoid: aldosterone – “Aldo stores Na” ➜ kidney Na^+ re-absorption / K^+ excretion.

Pancreas: Glucose Regulation

• \text{Insulin} – "Insulin put sugar in" cells ➜ ↓ blood glucose.

• \text{Glucagon} – "Glucagon raises glucose" ➜ liver glycogen → glucose.

Gonads

• Ovaries: estrogen (female traits, endometrium growth), progesterone (maintains lining, pregnancy).

• Testes: testosterone (male traits, spermogenesis).

• All sexes possess all three; concentrations differ.

Homeostatic Challenges

1. Maintain osmotic pressure (water/Na^+ balance).

2. Remove metabolic waste (CO₂, nitrogenous urea).

Accessory Excretors

• Skin (sweat), liver (detox, urea), lungs (CO₂).

Urinary System Anatomy

• Kidneys ➜ ureters ➜ bladder ➜ urethra.

• Each kidney ≈ 1{,}000{,}000 nephrons (functional units).

Filtration Journey

1. Glomerulus → Bowman’s capsule: BP pushes filtrate (water, glucose, ions, urea, small drugs/vitamins).

2. Proximal Convoluted Tubule (PCT)

   • Reabsorb: Na^+, H2O (osmosis), glucose, amino acids, K^+, HCO3^-.

   • Secrete: H^+, ammonia → pH tuning.

3. Loop of Henle

   • Descending limb: aquaporins → H_2O reabsorbed toward hypertonic medulla; salts stay.

   • Ascending thin: passive NaCl out; ascending thick: active NaCl out (no water) ➜ filtrate becomes dilute.

4. Distal Convoluted Tubule (DCT)

   • Secrete H^+, K^+, NH_4^+.

   • Reabsorb more salt, HCO_3^-, some water.

5. Collecting Duct

   • Final water re-absorption regulated by ADH & aldosterone; determines urine concentration.

   • Some urea recycles to medulla, aiding gradient.

Transport Mechanisms

• Passive (diffusion, osmosis) vs Active (ATP-dependent pumps up gradient).

Immune System Overview

Barriers (1st line)

• Skin, mucous membranes (nonspecific).

Innate Responses (2nd line)

• Inflammation: mast cells release histamine → vessels dilate/leak allowing WBC migration.

• Complement cascade enhances phagocytosis & lysis.

• Phagocytes: macrophages, neutrophils, eosinophils.

Adaptive Immunity (3rd line)

1. Cell-Mediated

   • Cytotoxic T (CD8⁺) cells induce apoptosis via perforin/granzyme when antigen displayed on infected cell.

   • Helper T (CD4⁺) cells activate both cytotoxic T & B cells.

2. Humoral

   • B cell activation (by antigen ± Helper T) ➜ plasma cells ➜ antibodies.

Antibody Classes ("GAMED")

• IgG: most abundant; crosses placenta; opsonization, complement.

• IgA: mucosal & secretions (saliva, milk) — first line on tracts.

• IgM: first made; pentamer; strong agglutinator.

• IgE: allergies, parasites.

• IgD: on naïve B-cell surface; initiation.

Memory Cells

• Memory B ➜ rapid antibody surge on re-exposure.

• Memory T ➜ swift cytotoxic response.

Active vs Passive Immunity

• Active: self-generated (infection, vaccine) → long-term.

• Passive: receive ready-made antibodies (maternal IgG, rabies Ig) → immediate, short-term.

Skeletal System

Functions

• Support, protection, leverage for movement, mineral storage (Ca, P), hematopoiesis (red marrow).

• Synergy with muscles ➜ “musculoskeletal system”.

Divisions

• Axial: skull (including ossicles & hyoid), vertebral column, rib cage.

• Appendicular: shoulder girdle + upper limbs, pelvic girdle + lower limbs.

• Adult total ≈ 206 bones; infants have more (fuse with age).

Bone Shapes & Examples

1. Long – cylindrical: femur, humerus, radius, phalanges.

2. Short – cube-like: carpals, tarsals.

3. Sesamoid – seed-like: patella.

4. Flat – thin/curved: cranial bones, scapulae.

5. Irregular – complex: vertebrae.

Bone Tissue

• Compact (cortical): dense outer layer.

• Spongy (cancellous/trabecular): inner lattice + marrow spaces.

  • Yellow marrow: fat/energy store.

  • Red marrow: hematopoiesis ➜ RBCs, WBCs, platelets.

Vascularity & Clinical Notes

• Fractures bleed; fat embolism risk from yellow marrow release.

• Intraosseous access: emergency meds/fluids via marrow cavity.

Bone Cells & Remodeling

• Osteoblasts – build bone (become osteocytes).

• Osteocytes – maintain matrix.

• Osteoclasts – resorb bone using lysosomal enzymes & acids.

• Remodeling cycle: Rest → Resorption (osteoclast pit) → Reversal → Formation (osteoblast osteoid) → Mineralization (Ca/P crystals) → Rest.

• Controlled to release/restore Ca^{2+} per PTH & calcitonin.

Cartilage Cells

• Chondroblasts form cartilage template; mature into chondrocytes.

• Remaining cartilage cushions joints.

Fracture Healing

1. Hematoma (blood clot) ➜ dying cells.

2. Internal (cartilage) + External (cartilage & bone) callus forms.

3. Osteoclasts clear debris; osteoblasts lay new bone.

Common Fracture Types

• Closed/simple – skin intact.

• Open/compound – bone pierces skin.

• Comminuted – bone shattered.

• Impacted/buckle – ends driven together (common in kids’ arms).

• Greenstick – partial crack/bend in children’s soft bones.

Anatomical Terminology

Anterior (Ventral) Landmarks

• Cephalic (head), frontal (forehead), orbital (eye), buccal (cheek), nasal, oral, mental (chin).

• Cervical (neck), axillary (armpit), brachial (arm), antebrachial (forearm), carpal (wrist), palmar, pollex (thumb), digital/phalangeal (fingers).

• Thoracic (chest), sternal, mammary.

• Abdominal, umbilical.

• Pelvic, inguinal (groin), pubic.

• Coxal (hip), femoral (thigh), patellar, crural (shin), tarsal (ankle), pedal (foot), dorsum (top), hallux (big toe).

Posterior (Dorsal) Landmarks

• Occipital (skull base), acromial (shoulder), scapular, vertebral, dorsal (back), olecranal (elbow), lumbar (loin), sacral, coccygeal, gluteal, perineal.

• Popliteal (knee back), sural (calf), plantar (sole), calcaneal (heel).

Body Planes (think “stuck in a wall”)

1. Transverse (horizontal): superior vs inferior ➜ only rotation.

2. Frontal/Coronal: anterior vs posterior ➜ abduction/adduction side motions.

3. Sagittal (median/lateral): left vs right ➜ flexion/extension forward-back.

Directional Pairs & Examples

• Anterior vs Posterior: nose is anterior to ears.

• Medial vs Lateral: sternum medial to shoulders; ears lateral to eyes.

• Cms for tewSuperior vs Inferior: eyes superior to mouth.

• Proximal vs Distal (limbs): shoulder proximal to elbow; fingers distal to wrist.

These condensed notes integrate every key concept, mnemonic, clinical pearl, numeric fact, and anatomical reference mentioned in the video—ideal for rapid exam review or replacing the full transcript.