Untitled Flashcards Set

KIN 370 Exam 2 Study Guide

Integumentary System

Functions

• Protection: Shields from UV light, dehydration, chemicals, and infections.

• Temperature Regulation: Sweat glands (merocrine) and blood flow adjustments.

• Excretion: Removes salts, water, organic waste.

• Vitamin D Synthesis: UV light converts cholesterol to Vitamin D3 → Liver → Kidneys → Calcitriol (Ca2+ absorption).

• Lipid Storage: Found in the dermis and subcutaneous layers.

• Sensory Detection: Touch, pressure, pain, and temperature receptors.

• Immune Defense: Langerhans cells protect against pathogens and skin cancer.

• Wound Healing: Involves clotting, inflammation, tissue repair, and remodeling.

Layers of the Epidermis

1. Stratum Basale: Deepest layer, contains basal cells (stem cells), melanocytes (pigment production), and Merkel cells (touch sensitivity).

2. Stratum Spinosum: 8-10 layers of keratinocytes bound by desmosomes, contains Langerhans cells (immune response).

3. Stratum Granulosum: 3-5 layers of keratinocytes, keratin and keratohyalin production, water resistance, apoptosis (cell death) occurs here.

4. Stratum Lucidum: Only in thick skin (palms/soles), densely packed dead keratinized cells, transparent appearance.

5. Stratum Corneum: Outer protective layer, 15-30 layers of dead keratinized cells, provides waterproof barrier, prevents pathogen entry.

Skin Growth Cycle

• Cell Migration: Cells move from basal layer to corneum in ~4 weeks.

• Shedding Cycle: Dead cells slough off after ~6 weeks.

Hair and Growth Cycle

• Hair Functions: UV protection, sensory perception, insulation, reduces friction.

• Hair Anatomy: Composed of keratin, pigment derived from melanocytes.

• Hair Growth Phases:

  • Anagen: Active growth (2-5 years), follicle produces new cells.

  • Catagen: Regression (~2 weeks), follicle shrinks.

  • Telogen: Resting phase (~3 months), hair sheds and new cycle begins.

• Male Pattern Baldness: Genetic, linked to DHT (dihydrotestosterone) sensitivity, hair follicles shrink over time.

Exocrine Glands

• Sebaceous Glands: Produce sebum (oily secretion), lubricates and protects skin, antibacterial properties.

• Sweat Glands:

  • Merocrine (Eccrine): Active throughout life, thermoregulation, water-based secretion, helps maintain homeostasis.

  • Apocrine: Develop at puberty, found in armpits/groin, thick secretion with proteins/lipids (body odor due to bacterial breakdown), possible pheromonal function.

  • Ceruminous glands: Produce earwax, protects ear canal.

  • Mammary glands: Modified sweat glands that produce milk.

Skin Cancer Types

• Basal Cell Carcinoma: Least malignant, most common, originates in stratum basale, rarely metastasizes.

• Squamous Cell Carcinoma: Arises in stratum spinosum, can metastasize if untreated, often found on head, scalp, hands.

• Melanoma: Most dangerous, highly metastatic, originates in melanocytes. ABCDE rule for detection: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Elevation.

Skeletal System

Functions

• Support: Framework for the body, attachment sites for muscles.

• Storage: Calcium (Ca2+), phosphate, lipids.

• Blood Cell Production: Red and white blood cells in red bone marrow.

• Protection: Shields organs (skull, ribs, vertebrae).

• Leverage: Movement via muscle attachments, enables force application.

Bone Structure

• Compact Bone: Dense outer layer, provides strength.

• Spongy Bone: Porous inner layer, contains red bone marrow.

• Periosteum: Outer fibrous membrane, provides nutrient supply.

• Endosteum: Lines inner surface, involved in growth and repair.

Bone Cells

• Osteocytes: Mature bone cells, maintain matrix.

• Osteoblasts: Build new bone (ossification), secrete osteoid.

• Osteoclasts: Break down bone tissue (bone resorption), regulate calcium levels.

• Osteoprogenitor Cells: Stem cells that differentiate into osteoblasts.

Ossification & Bone Growth

• Intramembranous Ossification: Forms flat bones (skull, clavicle, mandible), develops from mesenchymal tissue.

• Endochondral Ossification: Replaces cartilage model with bone (most bones, including long bones), primary ossification center forms in diaphysis.

Calcium Regulation

• Parathyroid Hormone (PTH): Increases blood Ca2+ (stimulates osteoclasts, reduces kidney excretion, enhances intestinal absorption via calcitriol).

• Calcitonin: Lowers blood Ca2+ (inhibits osteoclasts, increases kidney excretion, promotes Ca2+ deposition in bones).

Bone Repair

1. Hematoma Formation: Blood clot forms at fracture site, inflammation begins.

2. Callus Formation: Fibrocartilage and collagen stabilize the break, new blood vessels form.

3. Ossification: Spongy bone replaces fibrocartilage.

4. Remodeling: Compact bone replaces spongy bone, restoring shape and function.

Articulations (Joints)

Joint Classifications

• Structural: Bony, fibrous, cartilaginous, synovial.

• Functional:

  • Synarthrosis: Immovable (sutures, gomphosis).

  • Amphiarthrosis: Slightly movable (pubic symphysis, intervertebral discs).

  • Diarthrosis: Freely movable (synovial joints—knee, elbow, shoulder, hip).

Knee Joint

• Ligaments:

  • ACL (anterior cruciate ligament): Prevents forward movement of tibia.

  • PCL (posterior cruciate ligament): Prevents backward movement of tibia.

  • MCL/LCL (collateral ligaments): Prevent side-to-side movement.

• Menisci: Absorb shock and stabilize joint.

• Injuries: ACL tears (more common in female athletes), "3 C’s" (collateral ligaments, cruciate ligaments, cartilage).

• Tommy John Surgery: UCL (ulnar collateral ligament) reconstruction, common in pitchers.

Muscle System

Muscle Contraction (Sliding Filament Theory)

1. Excitation: Nerve impulse releases ACh at neuromuscular junction.

2. Depolarization: Na+ enters muscle fiber, triggering action potential.

3. Ca2+ Release: Sarcoplasmic reticulum releases Ca2+.

4. Cross-Bridge Formation: Ca2+ binds to troponin, exposing actin binding sites, myosin heads attach.

5. Power Stroke: Myosin pulls actin towards center.

6. ATP Binding: Myosin detaches and resets.

This guide now contains expanded and highly detailed information for Exam 2, ensuring in-depth preparation. Let me know if you need any additional refinements!