Anatomy & Physiology Study Guide: Tissues, Integumentary System, and Skeletal System

Chapter 4: Tissues – The Living Fabric

Introduction

This chapter explores the structural and functional characteristics of the four basic tissue types, with a focus on epithelial tissue, connective tissue, muscle tissue, and nervous tissue. Understanding these tissues is fundamental to the study of anatomy and physiology.

• Epithelial Tissue: Covers body surfaces, lines cavities, and forms glands. Functions include protection, absorption, filtration, excretion, secretion, and sensory reception.

• Classification: Epithelia are classified by cell shape (squamous, cuboidal, columnar) and number of layers (simple, stratified).

• Endocrine vs. Exocrine Glands: Endocrine glands secrete hormones directly into the bloodstream; exocrine glands release secretions through ducts to body surfaces or cavities.

• Multicellular vs. Unicellular Glands: Multicellular glands have multiple cells forming a duct and secretory unit; unicellular glands (e.g., goblet cells) are single cells.

• Connective Tissue: Supports, protects, and binds other tissues. Types include connective tissue proper, cartilage, bone, and blood.

• Muscle Tissue: Responsible for movement. Types: skeletal, cardiac, and smooth muscle.

• Nervous Tissue: Composed of neurons and neuroglia; responsible for transmitting electrical signals.

• Wound Healing: Involves inflammation, organization, and regeneration or fibrosis.

• Cancer: Cancer can arise from mutations in tissue cells; understanding tissue structure aids in cancer treatment.

Example: The skin contains epithelial tissue (epidermis), connective tissue (dermis), muscle tissue (arrector pili muscles), and nervous tissue (sensory receptors).

Chapter 5: The Integumentary System

Introduction

The integumentary system consists of the skin, hair, nails, and associated glands. It serves as the body's first line of defense and plays a role in protection, sensation, and thermoregulation.

• Parts of the Integumentary System: Skin (epidermis and dermis), hair, nails, sebaceous (oil) glands, and sweat glands.

• Layers of the Skin:

  • Epidermis: Outermost layer, composed of keratinized stratified squamous epithelium.

  • Dermis: Middle layer, contains connective tissue, blood vessels, nerves, and glands.

  • Hypodermis (subcutaneous layer): Deepest layer, primarily adipose tissue.

• Functions of Skin: Protection, temperature regulation, sensation, metabolic functions, blood reservoir, and excretion.

• Glands:

  • Sebaceous glands: Secrete sebum (oil) to lubricate skin and hair.

  • Sudoriferous glands: Produce sweat for thermoregulation.

• Types of Skin:

  • Thick skin: Found on palms and soles; contains five epidermal layers.

  • Thin skin: Covers most of the body; contains four epidermal layers.

• Aging Effects: Skin thins, loses elasticity, and becomes more susceptible to damage and infection.

Example: Sweat glands help regulate body temperature by releasing sweat, which cools the skin as it evaporates.

Bones, Skeletal Tissues & Articulations (Chapters 6, 7 & 8)

Introduction

This section covers the structure and function of bones, cartilage, and joints, as well as bone development, growth, and repair. It also addresses common bone and joint disorders.

• Cartilage Types:

  • Hyaline cartilage: Provides support, flexibility, and resilience.

  • Elastic cartilage: Maintains shape and allows flexibility.

  • Fibrocartilage: Provides tensile strength and absorbs compressive shock.

• Bone Anatomy: Typical long bone consists of diaphysis (shaft), epiphyses (ends), and metaphysis (growth region).

• Bone Remodeling: Involves osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells).

• Ossification:

  • Intramembranous ossification: Bone develops from a fibrous membrane.

  • Endochondral ossification: Bone forms by replacing hyaline cartilage.

• Epiphyseal Plate: Growth plate where lengthwise bone growth occurs in children and adolescents.

• Hormonal Regulation: Growth hormone, thyroid hormone, and sex hormones regulate bone growth and remodeling.

• Bone Repair: Steps include hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling.

• Bone Disorders: Osteoporosis (decreased bone density), osteomalacia (softening of bones), and osteosarcoma (bone cancer).

• Homeostasis: Calcium and phosphate balance is critical for bone health.

• Joints (Articulations):

  • Types: Fibrous, cartilaginous, and synovial joints.

  • Synovial Joints: Freely movable; characterized by a joint cavity filled with synovial fluid.

  • Movements: Flexion, extension, abduction, adduction, rotation, and circumduction.

• Joint Disorders: Osteoarthritis, rheumatoid arthritis, and Lyme disease.

Example: The knee is a synovial joint that allows flexion and extension, and is commonly affected by osteoarthritis.

Table: Comparison of Cartilage Types

Type	Main Locations	Key Properties
Hyaline Cartilage	Articular surfaces, nose, trachea, ribs	Support, flexibility, resilience
Elastic Cartilage	Ear, epiglottis	Maintains shape, flexibility
Fibrocartilage	Intervertebral discs, pubic symphysis, menisci	Tensile strength, shock absorption

Key Equations

• Bone Remodeling Rate:

$\text{Bone Remodeling Rate} = \text{Osteoblast Activity} - \text{Osteoclast Activity}$

• Calcium Homeostasis:

$\text{Serum Ca}^{2+} = \text{Intestinal Absorption} + \text{Bone Resorption} - \text{Renal Excretion}$

Additional info: Academic context and definitions have been expanded for clarity and completeness.