Muscular and Nervous Tissue

Chapter 3

Human Anatomy & Physiology

Muscular Tissue

• Function• Contracts to produce

movement• Movement can be

voluntary or involuntary

Types of Muscular Tissue

• 3 Types

1. Skeletal

2. Smooth

3. Cardiac

Characteristics of Skeletal Muscle

• Appearance: striated (striped) and column-shaped cells (muscle fibers)– Alternating light and dark bands make

striations

• Location: Attached primarily to bones

• Control: Voluntary (conscious)

• Contracts quickly, tires easily (fatigable)

• Allows for wide range of forces to be generated

Skeletal Muscle Tissue - 400X

Smooth Muscle• Appearance: spindle-

shaped• Location: wall of hollow

organs– example: Intestines, urinary

bladder, ureters, blood vessels

• Control: Involuntary • Contracts rhythmically and

quickly

Smooth Muscle

Smooth Muscle Tissue - 400X

Cardiac Muscle

• Has features of both skeletal and smooth muscle- Like skeletal muscle, it has strong contractions and striated appearance- Like smooth muscle, it is under involuntary control and has rhythmic contraction

• Appearance: striated and branched

• Location: heart• Function: contraction

of heart pumps blood and causes the heartbeat

• Control: Involuntary

Cardiac Muscle Tissue - 400X

Nervous Tissue

• The ultimate control of all the organ systems is done by the nervous system.– Function: controls and coordinates all bodily

functions and responds to internal and external stimuli.

THINK…COMMUNICATION!

Nervous Tissue

• Found: brain, spinal cord, and peripheral nerves

• The cells that transmit messages (impulses) are called neurons.

Structure of a Neuron

Axon terminals

Myelin sheath

Cell body

Nodes Axon

Dendrites

Nucleus

Neuron Structure

• Dendrites extend from the cell body and carry impulses from the environment toward the cell body.

Neuron Structure

• The largest part of a typical neuron is the cell body.

• It contains the nucleus and much of the cytoplasm.

Neuron Structure

• The axon is the long fiber that carries impulses away from the cell body.

Neuron Structure

• The axon is sometimes surrounded by an insulating membrane called the myelin sheath.

Neuron Structure

There are gaps in the myelin sheath, called nodes, where the membrane is exposed.

• Impulses jump from one node to the next.

Neuron Structure

Impulses are then passed to the next cell by the axon terminals.