Q: Which equation best represents the relationship between the number of synapses in a reflex arc and the speed of the response?

$$\text{Response Time} \propto \text{Number of Synapses}$$

Question 1

Which of the following statements best describes a spinal reflex?

Accepted Answer

A rapid, automatic response triggered by specific stimuli and controlled in the spinal cord, functioning without input from the brain.

Question 2

A patient suffers damage to the anterior root of a spinal nerve. Which function would most likely be impaired?

Accepted Answer

Motor output to effectors such as muscles and glands.

Question 3

Which meningeal layer is directly anchored to the neural tissue of the spinal cord and is composed of a meshwork of elastic and collagen fibers?

Accepted Answer

Pia mater

Question 4

During a lumbar puncture (spinal tap), which space is the needle inserted into to withdraw cerebrospinal fluid?

Accepted Answer

Subarachnoid space

Question 5

Which of the following best explains the significance of the cauda equina?

Accepted Answer

It consists of extended anterior and posterior roots of spinal segments L2 to S5 and the filum terminale, resembling a horse's tail.

Question 6

A person with polio has lost the use of his leg muscles. Which area of his spinal cord would you expect the virus-infected motor neurons to be located?

Accepted Answer

Anterior gray horn

Question 7

Which of the following is TRUE regarding the organization of white matter in the spinal cord?

Accepted Answer

Descending tracts in the anterior columns carry motor commands from the brain to the body.

Question 8

Which connective tissue layer surrounds individual axons within a spinal nerve?

Accepted Answer

Endoneurium

Question 9

A dermatome is best defined as:

Accepted Answer

A specific bilateral area of skin supplied by a pair of spinal nerves.

Question 10

Which virus is responsible for causing shingles, and what is its mechanism?

Accepted Answer

Varicella-zoster virus; attacks neurons in posterior roots and sensory ganglia, causing a painful rash along the dermatome.

Question 11

Which ramus of a spinal nerve provides sensory and motor innervation to the skin and skeletal muscles of the back?

Accepted Answer

Posterior ramus

Question 12

Which major nerve plexus is responsible for innervating the diaphragm, and which spinal nerves contribute to it?

Accepted Answer

Cervical plexus; C1–C5

Question 13

Damage to which nerve of the cervical plexus would interfere with the ability to breathe?

Accepted Answer

Phrenic nerve

Question 14

Which nerve divides into the tibial nerve and common fibular nerve in the lower limb?

Accepted Answer

Sciatic nerve

Question 15

Which neural circuit pattern allows information from one neuron to be spread to several neurons or pools, enabling broad distribution of input?

Accepted Answer

Divergence

Question 16

Which type of reflex arc involves only one synapse between a sensory neuron and a motor neuron, resulting in a fast response?

Accepted Answer

Monosynaptic reflex

Question 17

Which of the following best describes the function of muscle spindles in the stretch reflex?

Accepted Answer

They are sensory receptors that detect changes in muscle length and trigger contraction to maintain muscle tone.

Question 18

During a withdrawal reflex, what happens to the limb on the side opposite the stimulus, and what is this response called?

Accepted Answer

It extends to support body weight; this is called the crossed extensor reflex.

Question 19

A positive Babinski reflex in an adult after a spinal injury indicates:

Accepted Answer

Damage to descending motor tracts, resulting in loss of inhibition.

Question 20

Which equation best represents the relationship between the number of synapses in a reflex arc and the speed of the response?

Accepted Answer

$$	ext{Response Time} \propto 	ext{Number of Synapses}$$

Study Notes: The Spinal Cord, Spinal Nerves, and Spinal Reflexes

Guida di studio - Domande di pratica

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