IF

In-depth Notes on Animal Structure and Function

Structure and Function in Animal Tissues

  • Structure fits function at all levels of organization within the animal body.
  • Key Definitions:
    • Anatomy: the study of structure.
    • Physiology: the study of function.
  • Hierarchy of Organizational Levels:
    • Cellular level: e.g., muscle cell.
    • Tissue level: muscle tissue.
    • Organ level: heart.
    • Organ system level: circulatory system.
    • Organism level: many organ systems functioning together.

Tissue Types in Animals

  • Tissues: integrated groups of similar cells performing a common function.
  • Four Main Categories of Tissues:
    1. Epithelial tissue
    2. Connective tissue
    3. Muscle tissue
    4. Nervous tissue

Epithelial Tissue

  • Characteristics: sheets of closely packed cells covering body surfaces and lining internal organs and cavities.
  • Naming based on:
    • Number of cell layers
    • Shape of cells (e.g., squamous, cuboidal, columnar)
  • Types of Epithelial Tissue:
    1. Simple Squamous Epithelium:
    • Function: diffusion.
    • Location: walls of blood vessels, air sacs in lungs.
    1. Simple Cuboidal Epithelium:
    • Function: secretion and absorption.
    • Location: glands and kidneys (may have microvilli).
    1. Simple Columnar Epithelium:
    • Functions: secretion and absorption.
    • Location: lining of gut and respiratory tract (may have microvilli).
    1. Stratified Squamous Epithelium:
    • Function: protection (e.g., skin).
    • Composed of two or more layers of cells.

Connective Tissue

  • Definition: binds and supports other tissues.
  • Major Types of Connective Tissue:
    1. Loose connective tissue
    2. Fibrous connective tissue
    3. Adipose tissue
    4. Cartilage
    5. Bone
    6. Blood
  • Features:
    • Fiber types: collagenous, reticular, elastic.
    • Cell types: fibroblasts, macrophages.

Specific Connective Tissues

  1. Loose Connective Tissue:
    • Function: support, diffusion, and defense.
  2. Fibrous Connective Tissue:
    • Location: tendons and ligaments (provides strength and elasticity).
  3. Adipose Tissue:
    • Function: fat storage, insulation, padding.
  4. Cartilage:
    • Function: cushions and resists compression; found at ends of bones, nose, etc.
  5. Bone:
    • Function: support, movement, protection, and blood cell production.
  6. Blood:
    • Function: transport of gases, nutrients, wastes, and defense against disease.

Muscle Tissue

  • Function: movement.
  • Three Types of Muscle Tissue:
    1. Skeletal Muscle: voluntary movements.
    2. Cardiac Muscle: pumps blood (involuntary).
    3. Smooth Muscle: moves walls of internal organs (involuntary, e.g., intestines).

Nervous Tissue

  • Function: forms a communication network in the body.
    • Components:
    • Neurons: conduct electrical impulses.
    • Supporting cells: insulate axons, nourish neurons, and regulate the fluid around neurons.

Organs and Organ Systems

  • Organs: composed of multiple tissues working together.
  • Example: Small intestine consists of columnar epithelium, connective tissue, and smooth muscle for food propulsion.
  • Organ Systems:
    • Composed of multiple organs.
    • Each system has specific functions and works with others to maintain homeostasis.

Organ Systems Overview

  1. Circulatory System: delivers oxygen and nutrients, removes carbon dioxide and wastes.
  2. Respiratory System: exchanges gases, supplying blood with oxygen and disposing of carbon dioxide.
  3. Integumentary System: protects against injury and dehydration.
  4. Skeletal System: supports the body and protects organs.
  5. Muscular System: facilitates movement and maintains posture.
  6. Urinary System: removes wastes, regulates blood composition.
  7. Digestive System: processes food and absorbs nutrients.
  8. Endocrine System: regulates body activities through hormones.
  9. Lymphatic System: returns excess body fluid and supports immune functions.
  10. Nervous System: coordinates body activities through electrical signals.
  11. Reproductive System: produces gametes and supports development in females.

Homeostasis

  • Definition: the maintenance of stable internal conditions despite changes in the external environment.
  • Mechanisms:
    • Negative feedback systems detect changes and counteract them to maintain balance.
  • Example of Regulating Body Temperature:
    • Hypothalamus detects changes and activates cooling/warming mechanisms (e.g., sweating, shivering).

Integumentary System

  • Structure: skin, hair, and nails.
  • Function: protect the body from environmental hazards.