Nervous system overview

Opening of sodium channels in the membrane of a neuron results in: depolarisation. increased negative charge inside the membrane. repolarisation. reestablishing the resting potential.

depolarisation.

Each of the following is a function of the nervous system, except : integrating sensory information. coordinating voluntary and involuntary activities. providing sensation of the internal and external environments. regulating or controlling peripheral structures and systems. directing activities that continue for extended periods, such as growth and pregnancy.

directing activities that continue for extended periods, such as growth and pregnancy.

A patient who show signs of myelin damage is likely to have neurological symptoms due to: problems with neurotransmission problems with maintenance of a membrane potential problems with impulse conduction (propagation) problems with creation of an impulse

problems with impulse conduction (propagation)

In the neuron, the dendrites are the parts that: carry information toward other cells receive stimuli from the environment or from other other neurons release neurotransmitter contain the nucleus and other organelles

receive stimuli from the environment or from other other neurons

The sodium-potassium exchange pump: transports potassium ions out of the cell during repolarisation. moves sodium and potassium down their chemical gradients. requires ATP in order to function. transports sodium ions into the cell during depolarisation.

requires ATP in order to function.

The last step in the activation of a reflex arc is the : activation of a motor neuron. activation of a sensory neuron. arrival of a stimulus. response of a muscle.

response of a muscle.

Extracellular fluid contains high concentrations of __________, while intracellular fluid contains high concentrations of __________. potassium, sodium cations, ions proteins, electrolytes sodium, potassium

sodium, potassium

The knee jerk reflex is an example of a : crossed extensor reflex. contralateral reflex. stretch reflex. polysynaptic reflex.

stretch reflex.

An impulse from one nerve cell is communicated to another nerve cell via the : receptor effector synapse cell body

synapse

Accidentally touching the hot burner of a stove will elicit a(n) __________ reflex. tendon stretch rooting withdrawal

withdrawal

The Moro reflex is usually present until about: 11-13 years of age 5-6 years of age 11-12 months of age 4-5 months of age

4-5 months of age

Multiple Sclerosis (MS) is a progressive autoimmune disease leading to demyelination of affected axons.What causes individuals with MS to experience problems with both movement and sensation? The disease targets general sensory nerves which reduce motor pathway reflexes. Nerve impulse conduction is slowed and may even cease, affecting muscle and sensory activity. Nerve impulse propagation speeds up, leaving insufficient time for the CNS to coordinate movement and sensation. The disease targets unmyelinated axons in the peripheral nervous system, causing muscles to contract involuntarily and abnormal sensations to be generated.

Nerve impulse conduction is slowed and may even cease, affecting muscle and sensory activity.

Immediately after an action potential has passed, which channels open to allow the membrane potential to return to normal? Potassium Chloride Sodium Calcium

Potassium

Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this toxin have on the function of neurons? The neuron would be unable to metabolise glucose The axon would be unable to generate action potentials. The neuron would take longer to recover after each action potential None, because the chemically gated sodium channels would still function.

The axon would be unable to generate action potentials.

How does the interior surface of a cell membrane of a neuron differ from the external surface when the neuron is at rest? The interior surface is positively charged and has fewer sodium ions The interior surface is negatively charged and has fewer sodium ions The interior surface is negatively charged and has more sodium ions The interior surface is positively charged and has more sodium ions

The interior surface is negatively charged and has fewer sodium ions

Tetrodotoxin is a toxin that blocks the voltage-gated sodium channels from opening. What effect would this have on the function of neurons? The refractory period would be shorter than normal. Neurons would depolarise more rapidly. Action potentials would lack a repolarisation phase. The neuron would be unable to conduct action potentials.

The neuron would be unable to conduct action potentials.

A synapse is : the point where the action potential is generated a specialised site where two axons communicate electrically. the point where neurotransmitters are assembled. a specialised site where cell to cell chemical communication takes place.

a specialised site where cell to cell chemical communication takes place.

The first step in the activation of a reflex arc is the : information processing. activation of a sensory receptor. activation of a motor neuron. inhibition of a sensory neuron.

activation of a sensory receptor.

Nerves that carry impulses toward the CNS are: motor nerves efferent nerves afferent nerves mixed nerves

afferent nerves

Sensory neurons travelling in a cranial nerve would be part of the __________ division of the __________. efferent, PNS afferent, PNS afferent, CNS efferent, CNS

afferent, PNS

Testing a reflex can give information about: the sensory neuron involved in the reflex the motor neuron involved in the reflex the central nervous system all of the above

all of the above

During the withdrawal reflex the pain neuron synapses with three other neurons effector muscles cause removal from the source of pain both stimulation and inhibition of motor neurons occurs all of the above are correct

all of the above are correct

The stretch reflex: is an example of a polysynaptic reflex. is activated by sensory organs in the tendon is important in regulating posture. is activated when a skeletal muscle shortens.

is important in regulating posture.

Spinal nerves are : sensory. motor. mixed. None of the above are true.

mixed