A&P Exam 2

 Tissues & ECM  

 Four main tissue types:  

  1. Epithelial – Covers and lines surfaces.  

  2. Connective – Supports, connects, and protects.  

  3. Muscle – Produces movement.  

  4. Nervous – Sends and processes signals.  

 Two main components of any tissue:  

  1. Cells – The living part.  

  2. Extracellular Matrix (ECM) – Nonliving substance that provides support.  

•  Tissues with lots of ECM: Bone, cartilage.  

•  Tissues with little ECM: Epithelial tissue, muscle.  

 Fibers in ECM  

 Collagen fibers: Strong and resist tension (found in tendons, ligaments).  

 Reticular fibers: Thin, supportive meshwork (found in lymph nodes, spleen).  

 Elastic fibers: Stretch and recoil (found in skin, arteries, lungs).  

 Cell Junctions  

 Tight junctions: Seals between cells, nothing gets through (found in intestines).  

 Desmosomes: Strong connections, allow some stretching (found in skin).  

 Gap junctions: Tunnels for communication (found in heart cells).  

 Epithelial Tissue  

 Arrangements: Simple (one layer), Stratified (multiple layers), Pseudostratified (looks layered but isn’t).  

 Cell shapes: Squamous (flat), Cuboidal (cubelike), Columnar (tall).  

 Functions: Protection, absorption, secretion.  

 Keratin: Strengthens epithelial cells (found in skin).  

 Mucus: Provides lubrication and protection (found in respiratory tract).  

 Connective Tissue  

 Has lots of ECM, except in adipose (fat).  

 Cells in connective tissue: Fibroblasts (make fibers), Mast cells (immune response).  

 Resident cells: Stay in the tissue.  

 Migrant cells: Move around (e.g., immune cells).  

 Cells & Obesity  

 Phagocyte: Eats bacteria (immune cell).  

 Adipocyte: Fat cell.  

 Hypercellular obesity: More fat cells.  

 Hypertrophic obesity: Bigger fat cells.  

 Cartilage & Bone Formation  

 Chondroblasts: Make cartilage.  

 Chondrocytes: Mature cartilage cells (like osteocytes in bone).  

 Perichondrium: Surrounds cartilage (like periosteum in bone).  

 Membranes  

 Synovial membranes: Membranelike, in joints.  

 Mucous membranes: True membranes, line body cavities that open to the outside.  

 Membrane that can get inflamed (friction rub): Serous membrane.  

 Serous membranes repair? Regeneration, because they’re epithelial.  

 Integumentary System (Skin)  

 Functions of skin: Protection, temperature regulation, sensation, vitamin D production.  

 Thermoregulation: Sweat glands activate → evaporative cooling; blood vessels dilate/constrict.  

 Vitamin D & calcium: Skin makes vitamin D → helps absorb calcium for bones.  

 Epidermis Layers (Superficial to Deep)  

1. Stratum corneum: Dead, flat cells.  

2. Stratum lucidum: Only in thick skin (palms, soles).  

3. Stratum granulosum: Waterproofing layer.  

4. Stratum spinosum: Strength & flexibility.  

5. Stratum basale: New cells form here.  

 Thick skin vs. thin skin: Thick skin has stratum lucidum & no hair.  

 Dermis  

 Two layers:  

   Papillary layer: Thin, has capillaries (important for nutrients & temperature regulation).  

   Reticular layer: Thick, strong, has sensory structures and glands.  

 Melanin & Skin Color  

 Made in melanocytes (stratum basale).  

 Function: Protects against UV damage.  

 Blue skin (cyanosis): Due to lack of oxygen, not melanin.  

 Hair, Nails & Glands  

 Hair growth: Cycles through growth and rest phases.  

 Burt Reynolds' hair: Terminal hair (thicker, found on scalp & face).  

 Eccrine vs. Apocrine sweat glands:  

   Eccrine: Cooling (everywhere, mostly palms/soles).  

   Apocrine: Smelly sweat (armpits, groin).  

 Sebaceous glands: Produce oil (sebum), infections cause acne.  

 Burns & Skin Cancer  

 Most painful burn: Second degree (damages nerves but not fully destroyed).  

 Burn requiring grafts: Third degree (destroys entire skin layer).  

 Basal vs. squamous cell carcinoma:  

   Basal: Most common, slow-growing.  

   Squamous: More aggressive but treatable.  

 Malignant melanoma: Deadliest, spreads fast.  

 Skeletal System  

 Functions: Support, movement, protection, blood cell production, mineral storage.  

 Long bone anatomy:  

   Diaphysis: Shaft.  

   Epiphysis: Ends.  

    Sharpey’s fibers: Attach periosteum to bone.  

 Compact bone anatomy:  

   Lacuna: Small space with osteocyte.  

    Haversian canal: Blood vessel passage.  

 Bone Growth & Remodeling  

 Organic ECM: Collagen (flexibility).  

 Inorganic ECM: Minerals (hardness).  

 Osteoblasts make ECM → become osteocytes when trapped in matrix.  

 Bone growth types:  

   Intramembranous ossification: From embryonic tissue.  

   Endochondral ossification: From cartilage.  

   Longitudinal growth: Lengthens bones.  

   Appositional growth: Thickens bones (continues for life).  

 Hormones & bone growth:  

   Growth hormone: Increases bone length.  

   Testosterone: Increases density.  

   Estrogen: Speeds up growth plate closure.  

 PTH vs. Calcitonin:  

   PTH: Raises blood calcium.  

   Calcitonin: Lowers blood calcium.  

 Fractures & Healing  

 Simple fracture: Bone stays inside skin.  

 Compound fracture: Bone breaks skin.  

 Bone repair steps:  

  1. Hematoma (blood clot).  

  2. Soft callus (cartilage forms).  

  3. Hard callus (bone replaces cartilage).  

  4. Remodeling.  

 Joints  

 Synarthroses: No movement (fibrous joints).  

 Synovial joints: Freely movable.  

 Fibrous joint with interosseous membrane: Syndesmosis.  

 Synovial fluid: Lubricates & nourishes joint.  

 Ligaments: Connect bone to bone.  

 Tendons: Connect muscle to bone.  

 Joint Issues & Movement  

 Joint problems: Arthritis, bursitis, dislocations.  

 Best advice for joint issues: Stay active, maintain healthy weight.  

 Joint types:  

   Uniaxial: Elbow (hinge).  

   Multiaxial: Shoulder (ballandsocket).  

 Movements:  

   Abduction: Move away from midline.  

   External rotation: Rotate outward.  

   Elevation: Lift (shrug).  

 Supination: Palms face up.  

 Stability vs. flexibility: More stability = less flexibility (e.g., shoulder vs. hip).