BIOS251 Exam 3 Weeks

Week 5 Concepts - Integumentary System

General Composition and Function of Integumentary System

  • Structure of Skin:

    • Epidermis: Keratinized stratified epithelium.

    • Dermis: Vascularized connective tissue.

    • Subcutaneous Layer (Hypodermis): Below the dermis, containing fatty tissue.

  • Accessory Structures:

    • Sweat glands.

    • Oil (sebaceous) glands.

    • Hair and nails.

Functions of Skin

  1. Protection

    • Guards against dehydration and infection.

    • Features like acid mantle, keratin, and antimicrobial peptides.

  2. Synthesis of Vitamin D

    • Important for calcium metabolism and bone health.

  3. Sensation

    • Represents the largest sense organ (contains receptors for touch, temperature, and pain).

  4. Thermoregulation

    • Maintains body temperature through sweat and blood flow adjustments.

  5. Nonverbal Communication

    • Reflects emotion and health through skin and hair appearance.

Gross and Microscopic Anatomy of Integumentary System

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Epidermis

  • Comprised of 5 cell types:

    1. Keratinized Stratified Squamous Epithelium - Protective layer.

    2. Keratinocytes - Main cell type, producing keratin.

    3. Melanocytes - Produce melanin; responsible for skin pigment.

    4. Langerhans Cells - Immune function.

    5. Merkel Cells - Tactile (touch) receptors.

  • Thick Skin:

    • Present on palms and soles (contains stratum lucidum).

  • Thin Skin:

    • Found elsewhere; lacks stratum lucidum.

Dermis

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  • Cutaneous Membrane: Combination of dermis and epidermis.

  • Contains collagen, elastic, and reticular fibers.

  • Structures include:

    • Blood vessels, nerve endings, cutaneous glands, hair follicles.

  • Dermal Papillae: Projections that create fingerprints.

  • Layers of the Dermis:

    • Papillary Layer:

      • Superficial, made of areolar tissue, rich in blood supply.

    • Reticular Layer:

      • Dense irregular tissue, contains hair follicles, cutaneous glands.

      • Sensory Receptors:

        • Meissner corpuscles (touch), Pacinian corpuscles (pressure), Ruffini corpuscles (light pressure).

    • Benign Conditions:

      • Stretch marks (tears in collagen).

      • Blisters (fluid buildup between epidermis and dermis).

Subcutaneous Layer (Hypodermis)

  • Composed of loose connective tissue (adipose, areolar).

  • Connects skin to underlying structures; provides insulation.

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Functions and Cells of the Epidermis

  • Keratinocytes:

    • Make up 90% of epidermal cells, produce keratin and waterproofing granules.

  • Melanocytes:

    • Provide UV protection by forming a melanin shield.

  • Langerhans Cells:

    • Mount immune responses against pathogens; vulnerable to UV light.

  • Merkel Cells:

    • Serve as touch receptors in the basal layer.

Functions and Cells of the Dermis

  • Papillary Layer: Supplies nutrients to the epidermis and regulates temperature.

  • Reticular Layer: Supports structures with fiber strength and elasticity.

  • Cell Types:

    • Adipocytes (fat storage) and fibroblasts (collagen production).

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Structure and Function of Hair

  • Hair Composition:

    • Medulla: Inner layer (loosely arranged).

    • Cortex: Outer layer (tight, stacked keratinized cells).

    • Cuticle: Overlapping cells (protective).

  • Hair Follicle: Diagonal tube where hair grows.

  • Arrector Pili Muscle: Contracts in response to stimuli (goosebumps).

Functions of Hair

  • Provides protection, warmth, and sensory functions.

  • Hair growth progresses through three stages:

    1. Anagen: Active growth (6-8 years).

    2. Catagen: Transition phase (2-3 weeks).

    3. Telogen: Resting phase (1-3 months).

Structure and Function of Nails

  • Nails: Protective keratin-rich structures.

  • Components include nail plate, root, and cuticle (eponychium).

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Structure and Function of Exocrine Glands

  • Eccrine Sweat Glands: Most abundant; regulate temperature by producing sweat.

  • Apocrine Sweat Glands: Associated with emotional stress; found in specific body areas.

  • Sebaceous Glands: Produce sebum for skin hydration.

  • Ceruminous Glands: Produce earwax (cerumen).

  • Mammary Glands: Modified glands producing milk during lactation.

Thermoregulation Mechanisms

  • Evaporative Cooling: Sweat evaporation reduces body heat.

  • Insensible Perspiration: Minor water loss (500 mL/day).

  • Heat stress scenario (diaphoresis): Up to 1L/hr sweating.

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Homeostatic Mechanisms of Skin

  • Coordinates with renal and muscular systems.

  • Burn Classifications:

    1. First Degree: Epidermis damage, heals quickly.

    2. Second Degree: Involves dermis, blistering.

    3. Third Degree: Full-thickness; often requires grafting.

    4. Fourth Degree: Extends beyond skin, affecting tissues.

Infection Control in Burns

  • Fluid loss management and debridement crucial for recovery.

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Skin Cancer Types

  • Basal Cell Carcinoma: Most common; rarely metastasizes.

  • Squamous Cell Carcinoma: Can metastasize; appears scaly.

  • Melanoma: Most aggressive; originates in melanocytes using the ABCD rule for identification.

Week 6 Concepts - Skeletal System

General Functions of Skeletal System

  • Six Major Functions:

    1. Blood formation.

    2. Structural / support.

    3. Protection of vital organs.

    4. Movement via muscle attachment.

    5. Mineral storage (calcium, phosphorous).

    6. Triglyceride storage in adipocytes.

Bone Matrix and Hormone Regulation

  • Bone Cells:

    • Include osteogenic, osteoblasts, osteocytes, and osteoclasts.

  • Bone Composition:

    • 85% hydroxyapatite, 10% calcium carbonate.

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Hormonal Influence on Bone Health

  • PTH: Increases blood calcium by activating osteoclasts.

  • Hormonal Factors: Leptin, serotonin inhibit osteoblast function.

  • Effects of High Blood Calcium:

    • Kidney stones and osteoporosis risks.

Structural Components of Bone

  • Microscopic Anatomy: Compact and spongy bone structures detailed.

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Types of Cartilage

  • Hyaline: Found at joints, growth plates.

  • Elastic: In external ear, provides flexible support.

  • Fibrocartilage: Provides tensile strength in joints.

Tissues in the Skeletal System

  • Includes tendons and ligaments maintaining joint stability.

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Classification of Bone

  • Types Based on Shape:

    • Long, flat, short, irregular, and sesamoid bones.

  • Long Bone Structure: Components like epiphysis, diaphysis, and articular cartilage.

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Physiology of Bone Formation (Ossification)

  • Ossification Phases: Development, remodeling, repair.

  • Types of Ossification: Intramembranous and endochondral.

Endochondral Ossification Steps

  1. Development of a cartilaginous framework.

  2. Formation of ossification centers.

  3. Development of medullary cavity.

  4. Secondary ossification centers develop.

  5. Epiphyseal plates close after growth.

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Zones of Epiphyseal Plate

  • Proliferation and Hypertrophy Zones: Growth and maturation processes.

  • Zone of Calcifying Cartilage: Mineralization towards diaphysis.

Bone Remodeling Process

  • Appositional Growth: Increase in bone width.

  • Factors affecting thickness include activity levels and hormonal regulation.

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Factors Related to Bone Remodeling

  • Nutritional, hormonal influences play significant roles.

  • Osteoporosis: When bone breakdown exceeds formation, leading to fragility.

Bone Repair Process

  1. Reactive phase (hematoma formation).

  2. Reparative phase (callus formation).

  3. Remodeling phase (smoothing edges).

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Axial Skeleton

  • Components: Skull, vertebral column, thoracic cage.

  • Functions: Protect brain, spinal cord, and vital organs.

Bone Identification in the Skull

  • Major Features: Paranasal sinuses, sutures, vertebral structure basics.

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Vertebral Column and Ribs

  • Different vertebrae types (C1-C7, T1-T12, L1-L5).

  • Rib Classification: True ribs, false ribs, and floating ribs.

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Thoracic Cage Structure

  • Provides support for thoracic cavity including ribs and sternum structure details.

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Appendicular Skeleton

  • Composed of limbs and girdles.

  • Differences in Male and Female Bones: Pelvic adaptations for childbirth in females.

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Lower Limb Anatomy

  • Key bones in the lower limbs and their structures.

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Joint Classification

  • Arthrology & Kinesiology: Understanding joints and movements.

  • Functional Classification: Synarthrosis, amphiarthrosis, diarthrosis.

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Structural Joints

  • Synovial Joints: Most complex, different types based on movement.

  • Types of Synovial Joints: Hinge, pivot, ball-and-socket, gliding joints.

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Characteristics of Synovial Joints

  • Components include articular capsule, synovial fluid, and tendons.

Movement Mechanics

  • Understanding different types of movements: flexion, extension, abduction, adduction.

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Specific Joint Examples

  • Shoulder & Knee Anatomy: Key structural components and movements at each joint.

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Calcium Homeostasis

  • Importance of calcium levels for bodily functions and hormone regulation.

  • Disorders related to calcium imbalances: osteoporosis, osteoarthritis, and rickets.