1) the muscle weakness of myasthenia gravis results from
a) insufficient acetylcholine release from presynaptic vesicles.
b) loss of acetylcholine receptors in the end-plate membrane.
c) the motor neuron action potential being too small to shock the muscle fibers.
d) excessive acetylcholinesterase that destroys the neurotransmitter.
e) inability of the muscle fiber to produce atp.
2) the following are the steps involved in transmission at a cholinergic synapse.
1. chemically-gated sodium channels on the postsynaptic membrane are activated.
2. calcium ions enter the synaptic terminal.
3. acetylcholinesterase hydrolyzes acetylcholine.
4. an action potential depolarizes the synaptic terminal at the presynaptic membrane.
5. the synaptic terminal reabsorbs choline.
6. acetylcholine is released from storage vesicles by exocytosis.
7. acetylcholine binds to receptors on the postsynaptic membrane.
8. calcium ions are removed from the cytoplasm of the synaptic terminal.
the correct sequence for these events is
a) 4, 2, 6, 7, 8, 5, 3, 1
b) 4, 2, 6, 7, 1, 8, 3, 5
c) 2, 4, 6, 7, 1, 8, 3, 5
d) 2, 5, 4, 6, 7, 1, 8, 3
e) 6, 4, 2, 7, 1, 8, 3, 5
3) during an inflammatory response to injury, which of the following is the least likely
in the region of the injury?
a) increase in basophils
b) increase in histamine
c) increase in blood flow
d) cold, pale skin
e) swelling
4) after fertilization, the first cell division is completed
a) within a few seconds.
b) within the hour.
c) about 6 hours later.
d) in 12 hours.
e) more than a day later.