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Nervous system and hormones
7 MDCAT Biology questions with answers and explanations.
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Insulin is produced by the:
- 1 Alpha cells of the pancreas
- 2 Beta cells of the pancreas
- 3 Adrenal cortex
- 4 Liver
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Correct answer: Beta cells of the pancreas
Beta cells in the islets of Langerhans make insulin, which lowers blood glucose. Alpha cells make glucagon.
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The approximate resting membrane potential of a neuron is:
- 1 +70 mV
- 2 0 mV
- 3 -70 mV
- 4 -120 mV
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Correct answer: -70 mV
The inside of a resting neuron is about 70 mV more negative than the outside, because of the sodium-potassium pump and leaky potassium channels.
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Which part of the brain coordinates balance and smooth movement?
- 1 Cerebrum
- 2 Cerebellum
- 3 Medulla oblongata
- 4 Hypothalamus
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Correct answer: Cerebellum
The cerebellum fine-tunes movement, posture and balance.
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The small gap between two neurons is called the:
- 1 Node of Ranvier
- 2 Axon hillock
- 3 Synapse
- 4 Dendrite
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Correct answer: Synapse
At a synapse, a neurotransmitter crosses the gap to pass the signal to the next cell.
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Which hormone mainly regulates the basal metabolic rate?
- 1 Thyroxine
- 2 Insulin
- 3 Adrenaline
- 4 Oestrogen
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Correct answer: Thyroxine
Thyroxine, from the thyroid gland, sets the speed of metabolism in most body cells.
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The fight or flight hormone released by the adrenal medulla is:
- 1 Cortisol
- 2 Aldosterone
- 3 Adrenaline
- 4 Glucagon
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Correct answer: Adrenaline
Adrenaline raises heart rate and blood glucose to prepare the body for sudden action.
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The myelin sheath on a neuron:
- 1 Slows down the impulse
- 2 Speeds up conduction of the impulse
- 3 Stores neurotransmitters
- 4 Makes the neuron shorter
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Correct answer: Speeds up conduction of the impulse
Myelin insulates the axon, so the impulse jumps from node to node (saltatory conduction), which is much faster.