10 terms

Module 7: The Muscular System Part 3

striated, involuntary, square ends, mononucleated, more sarcoplasm, larger mitochondria, large T-tubules, less sarcoplasmic reticulum
What is the general anatomy of cardiac muscle?
cardiac muscle fibers branch and interconnect within two separate networks: atria and ventricles
Describe the special characteristics of the heart muscle
through intercalated discs that connect neighboring cells.
How are the two networks atria and ventricles connected in the heart?
the discs are composed of desmosomes which hold the fibers together and gap junctions which allows direct communication btwn adjacent cells.
What are these intercalated discs?
contract/relaxes 75/min, higher oxygen requirement then regular tissue, require more ATP has a larger mitochondria. Generates little ATP via the glycogen-lactic acid pathway, but can use lactic acid to generate ATP.
Contraction is intrinsic meaning stimulated by within heart. Intrinsic stimulation comes form autorhythmic cells
Describe heart physiology
intrinsic contraction, contraction is stimulated from within, autorhythmic cells
What type of contraction does the heart use and what makes it special? what cells are involved
there is a larger influx of Ca++ into the sarcoplasm
Why does cardiac muscle remain contracted for longer?
smaller than skeletal muscle fibers, have 10-15 thin filaments per thick filament and have intermediate filaments that attach to dense bodies like Z discs. They form networks joined by gap junctions that are arranged in sheets or layers.
Smooth muscle Anatomy
The duration of contraction is longer than in skeletal muscle
Describe the contraction of smooth muscle:
involuntary control, stimulated by action potential from autonomic nervous system regulated by hormones and local factors
What is the regulation of smooth muscle contraction?