Animal Tissues Overview

Study Notes

Animal tissues are groups of connected cells that work together to perform specific functions in an animal.

Epithelial tissue: Covers body surfaces and lines body cavities.
Muscle tissue: Enables movement.
Nerve tissue: Facilitates communication.
Connective tissue: Supports, connects, or separates different tissues and organs.

General functions include acting as barriers between the external environment and internal organs, secretions, and protections.
Two major types:
- Simple Epithelia: Single layer of cells.
- Stratified Epithelia: Multiple layers of cells (2-20 or more).
Shapes:
- Squamous: Flat, thin cells.
- Cuboidal: Cube-shaped cells.
- Columnar: Column-shaped cells.
Locations in the body vary depending on type and function.
Simple squamous epithelium is found in capillaries and air sacs of the lungs (alveoli).
Cuboidal epithelium are in kidney tubules and glands.
Columnar epithelium lines the digestive tract.

General functions include supporting, connecting, and separating tissues/organs; protecting, binding organs, and immune protection, and movement/heat production.
Components:
- Cells: Fibroblasts, macrophages.
- Fibers: Collagenous, reticular, elastic.
- Ground substance.
Types of fibrous connective tissue:
- Tendons: Attach muscles to bones.
- Ligaments: Connect bones at joints.
- Blood: Liquid connective tissue.
Blood composition:
- Plasma (55%): Liquid matrix, mainly water, electrolytes, nutrients, gases, hormones, and enzymes.
- Formed elements (45%): Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

Skeletal muscle: Voluntary movements of the body, striated.
Smooth muscle: Involuntary movements, found in walls of digestive tract, bladder, etc.; lacks striations.
Cardiac muscle: Limited to the heart, striated cardiomyocytes.

Specialized for communication via electrical and chemical signals.
Found in the brain and spinal cord.
Composed of neurons (nerve cells) with dendrites, axons, and axon terminals, for transmitting signals.