Ch.9 Muscles and Muscle Tissue Flashcards
Three types of muscle tissue are
Skeletal, cardiac, and smooth
Characteristic of Skeletal muscle
striated,voluntary, responsible for overall body mobility
Characteristic of Cardiac muscle
only in the heart, Striated, intercalated disc, branching
Characteristic of Smooth muscle
visceral, nonstriated, spindle-shaped, involuntary
4 Special characteristics of Muscle Tissue
- excitability/ responsiveness (receive and respond to stimulus)
- Contractility (shorten)
- extensibility (extend or stretch)
- elasticity (recoil and resume)
4 Muscle functions
Producing movement maintaining posture and body position stabilizing joints generating heat protection
List the three connective tissue sheaths from external to internal
Epimysium “overcoat” surrounds the whole muscle
Perimysium surround each fascicle
Endomysium surround each individual muscle fiber
Plasma membrane
Sarcolemma
a red pigment that stores oxygen
myoglobin
A single fiber contains hundreds to thousands of rod-like ______ that run parallel to its length
Myofibrils
______ the smallest contractile unit of a muscle fiber, the functional unit of skeletal muscle
Sarcomere
The order of muscle structure
myofibrils> muscle fiber > fascicles > Muscles
Thick filaments consist of
protein myosin, two heads and two tails
Thin Filaments consist of
protein actin, tropomysosin (mom strand) , and troponin (dad gun)
During contraction, they link the thick and thin filaments together forming
cross bridges
The Sarcoplasmic reticulum regulates intracelllar level of ionic _____ , also final trigger for contraction
calcium
What are the changes when contraction occurs
the I bands shorten, the distance between successive Z discs shortens, the H zone disappear, and the contagious A bands move closer together but their length does not change
Each axon ending gives off several short, curling branches that collectively form an elliptical _________ with a single muscle fiber
Neuromuscular junction/ end plate
The axon terminal and the muscle fiber are exceedingly close but they remain separated by
synaptic cleft
Small membranous sacs containing the neurotransmitter ACh
synaptic vesicles
________ triggers electrical events that ultimately generate an action potentioal
Acetycholine
After ACh binds to the ACh receptors its effects are quickly terminated by ________
Acetylcholinesterase
A disease characterized by drooping eyelids, difficulty swallowing and talking and generalized muscle weakness, involves a shortage of ACh receptors
Myasthenia gravis
How does a motor neuron stimulate a skeletal muscle fiber
nerve impulse reaches end of axon, release of ACh into the synaptic cleft
ACh diffuses across the cleft and attaches to ACh receptors on the sarcolemma
ACh binding triggersa electrical events, action potential
Steps in Excitation-Contraction Coupling
- Action potential propagates along the sarcolemma and down the T tubules
- Calcium ions are released
- Calcium binds to troponin and removes the blocking action of tropomyosin
- Contraction begins, myosin binding to actin forms cross bridges
