What is the main function of muscle tissue?
Movement (moving bones, rhythmic heart beating, constricting/dilating tubes).
How does muscle tissue contribute to thermoregulation?
It produces heat as a byproduct of metabolism; shivering (muscle contractions) provides extra heat.
What are the three categories of muscle tissue?
Skeletal, Cardiac, and Smooth muscle.
Location of Skeletal Muscle
Attached to bones by tendons.
Control of Skeletal Muscle?
Voluntary (under conscious control).
Microscopic appearance of Skeletal Muscle?
Striated and Multinucleate (nuclei are peripherally located).
What is the function of muscle tone?
Subconscious contraction that maintains posture and body position.
Location of Cardiac Muscle?
The Heart.
Control of Cardiac Muscle?
Involuntary (self-exciting and rhythmic).
Microscopic appearance of Cardiac Muscle?
Striated, branched cells with a single, central nucleus.
What unique structures connect cardiac cells?
Intercalated Discs.
What do intercalated discs allow cardiac muscle to act as?
A Syncytium (a coordinated unit).
What is the Plateau Phase of Depolarization?
A sustained electrical phase in cardiac cells that prevents tetanus (seizing up).
Location of Smooth Muscle?
Walls of tubes and hollow organs (e.g., blood vessels, intestines).
Microscopic appearance of Smooth Muscle?
Unstriated with a single nucleus.
What is the coordinated contraction in the GI/Urinary tract called?
Peristalsis.
What is the primary calcium-binding protein in Skeletal and Cardiac muscle?
Troponin.
What is the primary calcium-binding protein in Smooth muscle?
Calmodulin (Smooth muscle does not use Troponin).
What is the main calcium source for Skeletal and Cardiac muscle?
Sarcoplasmic Reticulum (SR).
What is the main calcium source for Smooth muscle?
Mostly Extracellular Fluid (ECF).
What is the connective tissue layer surrounding a Group of Muscles?
Fascia (which forms the tendon).
What is the connective tissue layer surrounding the whole muscle?
Epimysium (Epi = upon).
What is the connective tissue layer surrounding a fascicle?
Perimysium (Peri = around).
What is the connective tissue layer surrounding an individual muscle fiber (cell)?
Endomysium (Endo = within).
