Muscle Physiology
Distinguish between the 3 types of
muscles and describe the four main
functions of muscles
Functions of Muscles
1. 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 tendons
4. 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
Review
1. 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?