Nervous coordination：練習題

In the mammalian nervous system, which of the following is a structural feature of a myelinated motor neurone that allows for the rapid transmission of nerve impulses?

In a cholinergic synapse, what is the role of acetylcholinesterase?

Which statement best explains the difference in visual acuity between the fovea and the periphery of the human retina?

What is the primary role of the refractory period in nerve impulse conduction?

Which factor would lead to the slowest speed of conductance along a neurone?

In nervous coordination, which structural component of a motor neurone is responsible for the rapid transmission of electrical impulses via saltatory conduction?

Explain how the all-or-nothing principle determines whether an action potential is generated when sodium ions enter the axon following a stimulus.

Explain how saltatory conduction increases the speed of a nerve impulse in a myelinated neurone compared to a non-myelinated neurone of the same diameter.

A researcher is studying the properties of a motor neurone in a mammalian species. The axon of this neurone has a diameter of \(15\) \(\mu m\) and is myelinated.

(a) Explain how the structure of this axon allows for the rapid conduction of nerve impulses compared to a non-myelinated axon. (2 points)
(b) The researcher increases the temperature of the neurone's environment from \(20^{\circ}C\) to \(30^{\circ}C\). Explain why this results in a higher speed of conduction. (2 points)

In humans, the sinoatrial node (SAN) acts as the primary pacemaker for the heart.

(a) Describe the role of the atrioventricular node (AVN) and the Purkyne tissue in ensuring the ventricles contract effectively. (3 points)
(b) Explain how the autonomic nervous system coordinates an increase in heart rate when chemoreceptors detect a decrease in blood pH. (2 points)