Physiology – Muscles

which is the smallest structure:
1. Myofibril
2. Myofilament
3. Myosin
4. Muscle fiber
Myosin

which structural protein of skeletal muscle also acts as an enzyme?
myosin heavy chains

describe the pathology associated with periodic paralysis
skeletal muscles are plagued by being flaccid for short periods

what are the ions directly associated with all forms of periodic paralysis due to the fact that the channels for these ions are defective?
sodium and calcium

how does the permanent depolarization of the skeletal muscle result in a flaccid (non-contracted) paralysis?
the muscle cell would not be able to depolarize a second time because the voltage-gated sodium channel never inactivates

what happens when calcium binds troponin?
tropomyosin is pulled away from the actin active site

because of their shape, muscle cells are also known as ___ ___.
muscle fibers

thick filaments are composed of ____?
myosin

how does the process of smooth muscle contraction differ from contraction in skeletal muscle?
calcium comes from the extracellular fluid as well as the SR

how are cardiac muscle cells similar to smooth muscle cells?
they are electrically linked to one another

action potential propagation in a skeletal muscle fiber ceases when ACh is removed from the synaptic cleft. what mechanism ensures a rapid and efficient removal of ACh?
ACh is degraded by acetylcholinesterase

the neuromuscular junction is a well-studied example of a chemical synapse. what describes a critical event that occurs at the neuromuscular junction?
ACh is released by axon terminals of the motor neuron

action potentials travel the length of the axons of motor neurons to the axon terminals. these motor neurons extend from where to where?
extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber

calcium entry into the axon terminal triggers what event?
synaptic vesicles fuse to the plasma membrane of the axon terminal and release ACh

ACh binds to its receptor in the sarcolemma and triggers ___?
the opening of ligand-gated cation channels

why don’t sodium and potassium ions diffuse in equal numbers through ligand-gated cation channels?
the inside surface of the sarcolemma is negatively charged compared to the outside surface; sodium ions diffuse inward along favorable chemical and electrical gradients

what causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?
arrival of an action potential

the binding of calcium to which molecule causes the myosin binding sites to be exposed?
troponin

a myosin head binds to which molecule to form a cross bridge?
actin

what causes the myosin head to disconnect from actin?
binding of ATP

what causes the power stroke?
release of ADP and Pi

Which of the following is CORRECTLY paired? skeletal muscle: voluntary control Muscle tissue does NOT ________. product blood cells WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample Which type …

An action potential enters the depths of a muscle fiber by way of __________. diffusion the T tubules the calcium ion channels the sarcoplasmic reticulum the actin myofilament the T tubules Which structure do the calcium ions bind to when …

The neuromuscular junction is a well-studied example of a chemical synapse. Which of the following statements describes a critical event that occurs at the neuromuscular junction? When the action potential reaches the end of the axon terminal, voltage-gated sodium channels …

Chapter 9 Muscles and Muscles Tissue (Mastering A&P) Which of the following is CORRECTLY paired? A. smooth muscle: striated B. cardiac muscle: nonstriated C. cardiac muscle: voluntary control D. skeletal muscle: voluntary control D. skeletal muscle: voluntary control What causes …

muscle fibers the name of elongated skeletal and smooth muscle cells skeletal muscle voluntary, striated, contracts rapidly, tires easily, must rest for short periods, tremendous power, adaptable WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU …

Sarcolemma Plasma membrane of a muscle cell (muscle fiber) Myofibril Rodlike bundle of contractile filaments (myofilaments) found in muscle fibers (cells). WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample …

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