Muscle Physiology

Distinguish between the 3 types of muscles and describe the four main

functions of muscles

Functions of Muscles1. Producing Movement- such as quick

movements, expressing emotion, circulating blood.

2. Maintaining Posture- Mainly through skeletal muscles which make tiny adjustments continuously.

3. Stabilizing Joints- through muscle tendons4. Generating Heat- skeletal muscle accounts for

40% of body mass and most responsible for heat generation through muscle contractions

Skeletal Muscles

• Location: attached to bones or to skin (mainly facial muscles)

• Shape and appearance: single, very long, cylindrical, multinucleated cells with obvious striations.

Skeletal Muscle: Can you see the striations and multiple nuclei???

Skeletal Muscle continued……• Connective Tissue: Epimysium, perimysium,

and endomysium

• Regulation of contraction: Voluntary, via nervous system control

Skeletal Continued….• Regulation of contraction: Voluntary via nervous

system controls

• Speed of contraction: Slow to fast

• Rhythmic Contraction: NO

Remember: Skeletal, Striated, and Voluntary

Cardiac Muscles

• Body Location: Walls of the heart

• Cell shape and appearance:– Branching chains of cells; uninucleate, striations;

intercalated discs

Cardiac Muscle Continued…

• Connective Tissue Components: Endomysium attached to the fibrous skeleton of the heart.

• Regulation of contraction: Involuntary; the heart has a pacemaker (keeps the rhythm); also nervous system controls; hormones

Cardiac Muscle Continued…

• Speed of contraction: Slow

• Rhythmic Contraction: Yes

Remember: Cardiac, striated, and involuntary

Smooth Muscle

• Body Location: Mostly in walls of hollow visceral organs (other then the heart)

• Cell shape and appearance: Single, fusiform, uninucleate; no striations

Smooth Muscle Continued

• Connective Tissue Components: Endomysium

• Regulation of Contraction: Involuntary; nervous system controls; hormones; chemicals; stretch

Smooth Muscle Continued….

• Speed of Contraction: Very Slow

If skeletal muscle was a speedy car then smooth muscle would be a heavy-duty construction vehicles (CAT)

• Rhythmic Contraction: Yes, in some

Review1. How do cells of the 3 types of muscle tissue

differ from one another anatomically?2. Which muscle type has the most elaborate

connective tissue wrappings?3. What does striated mean relative to muscle

cells?4. How do movements promoted by skeletal

muscles differ from those of smooth muscle?