Lesson 7: Organization of Animal Bodies and Homeostasis

Hierarchical Organization of the Animal Body

Cells ➔ Tissues ➔ Organs ➔ Organ Systems ➔ Organism.

Epithelial Tissue

Covers body surfaces, forming barriers

Connective Tissue

Supports, binds, and protects other tissues

Muscle Tissue

Characterized by the ability to contract

Nervous Tissue

Composed of neurons that conduct impulses and neuroglia that support and protect neurons.

Homeostasis

The internal balance of animals maintained through regulation of temperature, pH, glucose, and oxygen levels.

Negative Feedback Loops

Mechanisms that maintain homeostasis by reversing deviations from set points, such as body temperature control.

Positive Feedback Loops

Reinforce changes in a system, moving conditions further from the set point until the stimulus is removed, such as during childbirth.

Endotherms

Organisms that generate heat internally, such as mammals and birds.

Ectotherms

Organisms that rely on external heat sources, such as fish and reptiles.

Simple Epithelial Tissue

A single layer of cells that lines surfaces and cavities in the body, facilitating absorption, secretion, and filtration.

Stratified Epithelial Tissue

Consisting of multiple cell layers, providing protection against mechanical stress and abrasion.

Pseudo stratification

A type of epithelial tissue that appears to have multiple layers due to varying cell heights but actually consists of a single layer

Squamous Epithelial Tissue

Characterized by flat, scale-like cells that facilitate diffusion and filtration in areas such as the alveoli of the lungs and blood vessels.

Cuboidal Epithelial Tissue

Composed of cube-shaped cells, primarily involved in secretion and absorption in glands and kidney tubules.

Columnar Epithelial Tissue

Composed of tall, column-like cells that are specialized for absorption and secretion, commonly found in the digestive tract and respiratory system.

Connective tissue proper

Provides support, binds other tissues together, and stores energy, including loose and dense

Special Connective Tissues

that have unique properties and functions, including adipose tissue, cartilage, bone, and blood.

Neuroglia

Supportive cells in the nervous system that protect, nourish, and maintain neurons.

Epidermis

The outermost layer of skin, providing a protective barrier and containing no blood vessels.

Dermis

The inner layer of skin located beneath the epidermis, which contains blood vessels, connective tissue, hair follicles, and sensory receptors.

Hypodermis

The deepest layer of skin, consisting of loose connective tissue and fat cells, which provides insulation and cushioning.

Integumentary System

The organ system that includes the skin, hair, nails, and associated glands, serving to protect the body, regulate temperature, and provide sensory information.

Gap Junctions

Specialized intercellular connections that facilitate communication and transport of ions and small molecules between adjacent cells.

Radiation

Indirect heat transfer (sun) warm to cold

Conduction

Direct heat transfer (rock) warm to cold

Convection

Heat transfer through the movement of fluids (liquids/water or gases/air) where warmer areas rise and cooler areas sink, creating circulation.

Evaporation

Heat loss through conversion of liquid to gas (body)