Exam 3 Study Guide Flashcards
(47 cards)
What is the epimysium?
surrounds the muscle; “overcoat” of dense irregular connective tissue that surrounds entire muscle
What are fascicles?
grouped muscle fibers; resemble bundle of sticks
What is the perimysium?
layer of dense irregular connective tissue that surrounds each layer of the fascicle
What is insertion?
movable bone
What is origin?
the less movable bone
What are the three basic types of muscle tissue? Which are voluntary and involuntary?
skeletal, smooth, and cardiac; skeletal is voluntary, smooth and cardiac are involuntary
How do actin and myosin interact?
myosin and actin drive skeletal muscle contraction; myosin binds to actin to contract muscle
Why is calcium important?
Calcium binds to troponin to change shape and remove tropomyosin; Ca provides the final “go signal” for contraction
What is the sarcolemma?
plasma membrane of the muscle fiber
Describe the sliding filament model of muscle contraction.
states that during the contraction, the thin filaments slide past the thick ones so that the actin and myosin filaments overlap to a greater degree
How are muscle fibers stimulated to contract?
an action potential travels along the nerve, down the sarcolemma, through its t tubules, and the sarcoplasmic reticulum releases Ca to to bind to troponin
Describe the events that occur at the neuromuscular junction.
-the motor neuron releases ACh that stimulates the skeletal muscle fiber, causing a local depolarization
-muscle fiber excitation; EPP triggers an action potential that travels across sarcolemma
-excitation contraction coupling; AP in sarcolemma propogates along the t tubules and causes release of Ca from terminal cisterns of the SR.
-cross bridge cycling; muscle contracts as a result of a repeating cycle of steps that cause myofilaments to slide relative to each other
What does ACh do?
binds to receptor proteins on the sarcolemma and triggers an action potential
What does acetylcholinesterase do?
breaks down ACh
What is the difference between oxidative slow twitch muscle fibers and glycolytic muscle fibers?
Oxidative slow twitch muscle fibers are for low intensity long lasting muscle contractions. Glycolytic muscle fibers are best suited for short term rapid intense movements
Why are gap junctions important for smooth muscle?
gap junctions are communicating junctions between adjacent cells. In smooth muscle, they coordinate changes in both membrane potential and intracellular Ca between adjacent smooth muscle cells
What protein binds calcium in smooth muscle?
calmodulin
What are the structural divisions of the nervous system?
-central nervous system(brain & spinal cord); the control center of the nervous system
-peripheral nervous system(nerves that branch off and extend throughout the body); they carry impulses to and from the brain
What is the afferent pathway?
information traveling across the afferent pathway approaches the control center
Efferent pathway
output flows from the control center along the efferent pathway to the third component
What are the types of neuroglia in the CNS?
-astrocytes
-microglial cells
-ependymal cells
-oligodendrocytes
What are the types of neuroglia in the PNS?
-satellite cells
-schwann cells
Astrocytes
most abundant and versatile glial cells; support and brace neurons and anchor them to their nutrient supply lines
Microglial cells
small and ovoid with relatively long thorny processes; processes touch nearby neurons, monitoring their health and migrate towards neurons that are injured
