1403 - Week 12 Online Quiz Flashcards

1. The T-tubule network is important in skeletal muscle due to:

----

A.

the large size of skeletal muscle cells requiring a system to bring action potentials into proximilty with internal structures

B.

it allows a large surface area by which skeletal muscle cells can bring extracellular calcium ions into the cell to activate contraction

C.

it is the fundamental contractile unit of the cell

D.

all of the above

1. The sarcomere

A.

is present in all types of muscle cells (cardiac, smooth and skeletal)

B.

is the contractile apparatus in all types of muscle cells

C.

stores calcium for release in skeletal and cardiac muscle tissue and is what gives these tissues their striated appearance

D.

gives cardiac and skeletal muscle their striated appearance, due to the arrangement of actin and myosin proteins

1. Motor information in the corticospinal tract decussates at

A.

the medulla and the spinal cord and thus remains on the same side of the body

B.

the medulla only

C.

the spinal cord only

D.

at the medulla or the spinal cord depending on whether it is the anterior or the lateral tract

1. The following are the steps involved in transmission at the neuromuscular junction.-----
2. 1. Chemically gated sodium channels on the postsynapticmembrane are activated
   2. Calcium ions enter the synaptic knob
   3. Acetylcholinesterasebreaks down acetylcholine
   4. An action potential depolarizes the synaptic knob at the presynaptic membrane
   5. The synaptic knob reabsorbs choline
   6. Acetylcholine is released from storage vesicles by exocytosis
   7. Acetylcholine binds to receptors on the postsynaptic membrane
   
   The correct sequence for these events is

2, 4, 6, 7, 1, 3, 5

4, 2, 6, 7, 1, 3, 5

6, 4, 2, 7, 1, 3, 5

4, 2, 6, 7, 5, 3, 1

2, 5, 4, 6, 7, 1, 3

1. The descending motor tract that has a major role in controlling the wrist is the

A.

lateral spinothalamic

B.

tectospinal

C.

rubrospinal

D.

reticulospinal

1. Which statement correctly describes a feature of the sympathetic nervous system?

A.

preganglinonic neurons have long axons that exit the spinal cord through the white ramus

B.

preganglionic neurons utilise the neurotransmitter acetycholine and exit the spinal cord through the gray ramus

C.

postganglionic neurons typically use the neurotransmitter noradrenaline and exit the spinal cord through the white ramus communicans

D.

postganglionic neurons cell bodies are located in either the chain ganglia, collateral ganglia or adrenal medulla and are activated by the neurotransmitter acetylcholine

1. If the axon terminal of a motor neuron suddenly became permeable to calcium ion,

A.

neurotransmitter release would be blocked

B.

the neuron would fire an action potential

C.

the motor end plate would be hyperpolarized

D.

the motor end plate would be depolarized

1. Which of the following is the correct sequence of events for skeletal muscle contractions?

A.

motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments

B.

neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke

C.

muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments

D.

neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke

1. The ventral root of a spinal nerve contains

A.

axons of motor neurons

B.

interneurons

C.

cell bodies of motor neurons

D.

axons of sensory neurons

E.

cell bodies of sensory neurons

1. Which of the following motor reflexes involves reciprocal inhibition?

Stretch

Crossed extensor

Withdrawal

Golgi tendon

Visceral