4 Types of Tissues Epithelial

Covers body surfaces and lines hollow organs, body cavities, duct, and forms glands

Connective Protects, supports, and binds organs. Stores energy as fat, provides immunity

Muscular Generates the physical force needed to make body

structures move and generate body heat Nervous

Detect changes in body and responds by generating nerve impulses

Development of Tissues Tissues of the body develop

from three primary germ layers: Ectoderm, Endoderm,

and Mesoderm Epithelial tissues develop

from all three germ layers All connective tissue and

most muscle tissues drive from mesoderm

Nervous tissue develops from ectoderm

Internal organs develop from endoderm

Tight Junctions

Web-like strands of transmembrane proteins Fuse cells together Seal off passageways

between adjacent cells Common in epithelial

tissues of the stomach, intestines, and urinary bladder

Help to retard the passage of substances between cells and leaking into the blood or surrounding tissues

Desmosomes

Contain plaque and cadherins that extends into the intercellular space to attach adjacent cells together Desmosome plaque

attaches to intermediate filaments that contain protein keratin

Prevent epidermal cells from separating under tension and cardiac muscles cells from pulling apart during contraction

Gap Junctions

Connect neighboring cells via tiny fluid-filled tunnels called connexons Contain membrane proteins

called connexins Plasma membranes of gap

junctions are separated by a very narrow intercellular gap (space) Communication of cells

within a tissue Ions, nutrients, waste,

chemical and electrical signals travel through the connexons from one cell to another

Epithelial Tissues Epithelial tissue consists of

cells arranged in continuous sheets, in either single or multiple layers Closely packed and held tightly

together Covering and lining of the body Free surface

3 major functions: Selective barrier that regulates

the movement of materials in and out of the body

Secretory surfaces that release products onto the free surface

Protective surfaces against the environment

Connective Tissue Most abundant and widely

distributed tissues in the body

Numerous functions Binds tissues together

(tendons/ligaments) Supports and strengthen

tissue (bone) Protects and insulates internal

organs (fat) Compartmentalize and

transport (blood) Energy reserves and immune

responses

Connective Tissue Extracellular Matrix Ground substance

Between cells and fibers Fluid, semifluid, gelatinous, or calcified

Functions to support and bind cells, store water, and allow exchange between blood and cells

Complex combination of proteins and polysaccharides

Fibers Collagen fibers Elastic fibers Reticular fibers

Muscular Tissue Consists of elongated

cells called muscle fibers or myocytes Cells use ATP to

generate force Functions in movement,

generating heat, digestion

Classified into 3 types: skeletal, cardiac, and smooth muscular tissue

Skeletal Muscle Tissue

Attached to bones of the skeleton Have striations Voluntary movement or contractions by conscious control Vary in length (up to 40 cm) and are roughly cylindrical in

shape

Muscular Tissue

Cardiac muscle tissue Have striations Involuntary movement or contraction is not consciously

controlled Intercalated disc unique to cardiac muscle tissue

Smooth Muscle Tissue Walls of hollow internal structures

Blood vessels, airways of lungs, stomach, and intestines Nonstriated Usually involuntary control

Nervous Tissue Consists of two principle types of cells

Neurons or nerve cells Neuroglia

Cellular Movement

Microtubules cilia & flagella Microfilamentsamoeboid

movement & muscle cells

Vertebrate skeletal muscle

The action of muscle is to always contract

Muscles are attached in antagonistic pairs

The basic functional unit of muscle

)Myofilaments

Skeletal muscles: striated & multinucleate

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