Test #2 Flashcards
Slow-twitch muscle fibers use ______ to especially enhance ATP production by ____
Myoglobin; oxidative phosphorylation
A toxin that blocks acetyl-choline gated sodium channels on skeletal muscle is likely to _____
Cause flaccid (floppy) paralysis of skeletal muscle
Put these events in chronological sequence for skeletal muscle:
- T tubules convey action potentials into the interior of the cell
- Acetylcholine binds to receptors on the sarcolemma
- Ca2+ is released from the sarcoplasmic reticulum
- Ca2+ ions bind to troponin, pulling on tropomyosin
2 –> 1 –> 3 –> 4
A drug that decreases the activity of myosin kinase has the potential to:
- Decrease blood pressure by causing vasodilation in patients with high BP
- Increase the rate of contractions to induce labor
- Increase rate of contractions in the large intestine
- Increase BP by causing vasoconstriction in patients with circulatory failure
Decrease blood pressure by causing vasodilation in patients with high BP
Paravalbumin is a protein that binds to calcium, removing it from the cytosol, in certain types of skeletal muscle, especially in birds or insects with high wing beat frequencies. What is an explanation of how this protein affects twitch speed?
It allows muscle to relax more quickly
What best describes the role of calcium in the excitation-contraction coupling reaction
Ca2+ will bind to troponin, which leads to a conformational shift in tropomyosin, allowing for actin and myosin to attach
What causes the myosin head to disconnect from actin
Binding of ATP
Compared to the interstitial fluid, the fluid in the t-tubules of skeletal muscle fibers
- has more potassium
- has more sodium
- has more calcium
- is identical
Is identical - t-tubules are filled with interstitial fluid
What causes the relaxation of smooth muscle?
Calcium removal from the cytosol, inhibition of myosin kinase, and activity of myosin phosphatase
The mechanism responsible for skeletal muscle fatigue appears to involve
Decreased effectiveness of action potentials along the t-tubules.
Neurotransmitters are typically released ______ into the synapse
From the pre-synaptic membrane of neurons
What does transduction in the olfactory system depend on?
Ligands binding to receptor neurons causing a graded and an action potential
Adrenergic receptors are known as either ____ or ____
Alpha or beta
Blood flow in a blood vessel can decrease (vasoconstriction) if that vessel has:
Alpha-adrenergic receptors
Touch neurons undergo graded depolarizations when
Mechanically-G Na+ channels are opened
Norepinephrine is released from the pre-synaptic membranes of
Post-ganglionic neurons in the sympathetic system
Trigeminal chemoreception includes responses to _____ stimuli and its activity is linked to ____
Noxious; breathing regulation
Which is a mismatch of stimulus and perception
- sweet;glucose
- salty; Na+
- umami; monosodium glutamate
- sour; capsaicin
Sour; capsaicin
Some taste transducing cells undergo _____ in response to the opening of _______ -gated ion channels
Graded but not action potentials; ligand
A drug that increases the activity of myosin phosphatase in smooth muscle has the potential to:
Make breathing easier for asthmatics by relaxing airway circular smooth muscle
A drug that causes voltage-gated potassium channels to stay open for an abnormallylonger period of time will cause the resting membrane potential of a neuron to be ______ normal
- more positive than
- more negative than
- less negative than
- unchanged from
more negative than
An agonist of nicotinic cholinergic receptors would likely cause
Tetanic paralysis of skeletal muscle
Which of the following toxins decreases ACh release?
- Pufferfish toxin
- Poison arrow frog toxin
- Botox
- Black widow spider toxin
Botox
T/F inside the t-tubule concentration of K+ is low, and Na+ is high
True
