Chapter 9 Flashcards
resting membrane potential
K is inside and negatively charged, NA is outside and positively charged
depolarization
NA channels open, NA goes inside and makes inside positively charged
repolarization
Na channels closed, K leaves, making inside negatively changed
repolarization
Na channels closed, K leaves, making inside negatively changed
Nerve signal arrives
Step 1
muscle fiber releases ACH
Step 2
ACH binds to receptors
Step 3
ligand-gated ion channel opens
Step 4
Action potentials occur
Step 5
action potentials enter T tubules
Step 6
calcium is released
Step 7
calcium binds to troponin
Step 8
complex reveals binding sites
Step 9
The junction between nerve endings and muscle fibers.
Neuromuscular junction
A rope-like organ that transfers information to the central nervous system.
Nerve
The enlargement at the end of an axon that secretes a neurotransmitter.
Synaptic knob
The vesicles in the axon containing neurotransmitters.
synaptic vesicles
A chemical in the neuromuscular junction that aids in stimulating or inhibiting muscle contraction.
neurotransmitter
A channel that opens or closes when a ligand is bound to the receptor site.
ligand-gated ion channel
The difference between the electric charge inside membrane and just outside the membrane.
RMP
A rapid change in membrane voltage.
EPP
A channel that opens or closes when a membrane reaches a certain voltage.
voltage-gated ion channel
The network of tubes and canals in the sarcolemma.
sarcoplasmic reticulum
A rapid change in a cell’s electrical charge that reverses the plasma membrane’s electrical polarity.
action potentials
Tube-like canals in the sarcolemma that deliver action potentials into the muscle fiber.
t tubules
Which of the following is NOT a function of skeletal muscle?
Select one:
a. body movement
b. maintenance of posture
c. Dilating and constricting the pupil of the eye
d. Carry out breathing movements
e. production of heat
c. Dilating and constricting the pupil of the eye
Smooth muscle is regulated by all of the following except
Select one:
a. the autonomic nervous system.
b. neurotransmitters.
c. the somatic nervous system.
d. hormones.
e. prostaglandins.
c. the somatic nervous system.
Which of the following statements concerning smooth muscle is true?
Select one:
a. It contains many sarcomeres.
b. Caveolae seem to take the place of the myofibrils.
c. A calcium-calmodulin complex initiates cross-bridge formation.
d. The cells are large and multinuclear.
e. It has a well developed sarcoplasmic reticulum.
c. A calcium-calmodulin complex initiates cross-bridge formation.
Which type of muscle tissue causes contraction of the heart?
Select one:
a. skeletal muscle
b. smooth muscle
c. cardiac muscle
c. cardiac muscle
Which of the following is true?
Select one:
a. Skeletal muscle is capable of spontaneous contraction.
b. Smooth muscle is found in the walls of hollow organs.
c. Cardiac muscle cells have multiple nuclei.
d. Smooth muscle cells are long and cylindrical.
e. There is a small amount of smooth muscle in the heart.
b. Smooth muscle is found in the walls of hollow organs.
List the following structures in order from smallest to largest.
(1) muscle fiber
(2) myofilament
(3) myofibril
(4) muscle fasciculus
Select one:
a. 4, 2, 3, 1
b. 2, 1, 4, 3
c. 3, 1, 4, 2
d. 2, 3, 1, 4
e. 1, 2, 3, 4
d. 2, 3, 1, 4
Why does muscle activity affect the temperature of the body?
Select one:
a. The rate of chemical reactions increases in muscle fibers during contraction, so the rate of heat production also increases.
b. Muscle contraction generates pyrogens which reset the body’s internal thermostat to a higher temperature.
c. Muscle activity directs more warm blood to the muscles away from the central core causing a cooling effect on your internal organs.
d. Increased muscle activity causes a rise in adipose stores which increases the insulation value of the body.
a. The rate of chemical reactions increases in muscle fibers during contraction, so the rate of heat production also increases.
Which of the following actions is caused by contraction of skeletal muscle?
Select one:
a. contraction of the heart
b. moving your feet in walking
c. movement of food through the digestive tract
d. emptying of the urinary bladder
e. vasoconstriction
b. moving your feet in walking
Muscles exhibit the property of excitability. This means that the muscle
Select one:
a. shortens its length.
b. recoils to its original resting length.
c. stretches beyond its normal length.
d. responds to stimulation by the nervous system.
e. excites itself.
d. responds to stimulation by the nervous system.
The capacity of a muscle cell to shorten forcefully is known as
Select one:
a. contractility.
b. excitability.
c. extensibility.
d. elasticity.
e. flexibility.
a. contractility.
Acetylcholine is released from the presynaptic terminal by the process of
Select one:
a. exocytosis.
b. diffusion.
c. phagocytosis.
d. active transport.
e. endocytosis.
a. exocytosis.