Muscle and Nervous Tissue

Pages 97-101

Function: ◦ contract (shorten) to produce movement

Three types:1.Skeletal muscle2.Cardiac muscle3.Smooth muscle

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Voluntary (consciously) control Attach to bones or skin Produce:

◦ gross body movements◦ facial expressions

Cell Characteristics:◦ Striations (stripes)◦ Multinucleate (more than one nucleus)◦ Long, cylindrical shape

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Figure 3.20a Type of muscle tissue and their common locations in the body.

Nuclei

Part of musclefiber

Photomicrograph: Skeletal muscle (195×)(a) Diagram: Skeletal muscle

Involuntar control only in the heart Pumps blood through blood vessels Characteristics of cardiac muscle cells

◦ Striations◦ One nucleus, short, branching cells

Look somewhat like bamboo◦ Intercalated discs:

Areas between cells which contain gap junctions to connect cells together so that the impulse spreads across the heart synchronously

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Figure 3.20b Type of muscle tissue and their common locations in the body.

Intercalateddiscs

Nucleus

Photomicrograph: Cardiac muscle (475×)(b) Diagram: Cardiac muscle

Compare the two- note the differences

Skeletal Cardiac

Involuntary control

Location: where constricting and enlarging is required

◦ walls of hollow organs Peristalsis: a wavelike activity that moves digested

material through the small intestine◦ blood vessels

Characteristics:◦ No visible striations◦ Single nucleus◦ Spindle-shaped cells

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Figure 3.20c Type of muscle tissue and their common locations in the body.

Smoothmuscle cell

Nuclei

Photomicrograph: Sheet of smooth muscle (285×)(c) Diagram: Smooth muscle

Two groups of cells:◦ Neurons◦ Neuroglia (glial cells)

these insulate, protect, and support neurons

Function: receive and conduct electrochemical impulses to and from body parts◦ Irritability◦ Conductivity

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Figure 3.21 Nervous tissue.

Brain

Spinalcord

Nuclei ofsupportingcells

Cell bodyof neuron

Neuronprocesses

Nuclei ofsupportingcells

Neuronprocesses

Cell bodyof neuron

Diagram: Nervous tissue

Photomicrograph: Neurons (320×)