Nervous System

Question 1

What are the 3 functions of the nervous system?

Answer 1

1. Sensory input – detects changes inside and outside the body.
2. Integration – processes and interprets sensory input.
3. Motor output – activates muscles/glands to respond.

Question 2

What structures make up the CNS and PNS, respectively?

Answer 2

CNS: Brain and spinal cord. PNS: Cranial nerves, spinal nerves, and peripheral nerves.

Question 3

What components make up a neuron?

Answer 3

Dendrites, cell body (soma), nucleus, axon, myelin sheath, nodes of Ranvier, axon terminals, synapse.

Question 4

What function does the myelin sheath serve?

Answer 4

Insulates axons to speed up nerve impulses.

Question 5

What is saltatory conduction?

Answer 5

Impulses jump between nodes of Ranvier for faster transmission.

Question 6

Differentiate between ganglia and nuclei.

Answer 6

Ganglia are clusters of neuron cell bodies in the PNS. Nuclei are clusters of neuron cell bodies in the CNS.

Question 7

What are the functional classifications of neurons?

Answer 7

1. Sensory (afferent) – carry signals to the CNS. 2. Motor (efferent) – carry signals from the CNS to muscles/glands. 3. Interneurons – connect neurons within the CNS.

Question 8

List the four main parts of the brain.

Answer 8

1. Cerebrum – top and largest part. 2. Diencephalon – under cerebrum (includes thalamus and hypothalamus). 3. Brainstem – base of brain. 4. Cerebellum – back of brain, under cerebrum.

Question 9

What are the separate roles of the three parts of the brain stem?

Answer 9

Midbrain: reflexes and eye movement. Pons: signal relay and breathing. Medulla oblongata: controls heart rate, breathing, blood pressure.

Question 10

What is the role of ventricles in the brain?

Answer 10

Produce and circulate cerebrospinal fluid (CSF), which cushions the brain and removes waste.

Question 11

List the layers of the meninges from internally to externally.

Answer 11

1. Pia mater (inner). 2. Arachnoid mater (middle). 3. Dura mater (outer).

Question 12

Explain the difference between the dorsal and ventral roots of the spinal cord.

Answer 12

Dorsal root: carries sensory input to the spinal cord. Ventral root: carries motor output from the spinal cord.

Question 13

Describe the ‘stretch reflex’ and its purpose.

Answer 13

Causes a muscle to contract in response to being stretched. Purpose: maintains posture and muscle tone.

Question 14

Differentiate between the sympathetic and parasympathetic divisions of the ANS.

Answer 14

Sympathetic: fight or flight – increases alertness, heart rate. Parasympathetic: rest and digest – slows heart, promotes digestion.

Question 15

What are the functional sub-divisions of the PNS?

Answer 15

1. Sensory division – carries info to CNS. 2. Motor division – carries info from CNS: includes Somatic (voluntary) and Autonomic (involuntary) systems.

Question 16

Label Diagram of Divisions of the nervous system

Answer 16

Question 17

What is the function of CNS? (4 points)

Answer 17

• Consists of the brain and spinal cord (see diagram)
• Is the integration and control center of the body
• Interprets, processes and stores sensory input
• Initiates motor output

Question 18

What is the function of PNS? (5 points)

Answer 18

• Is the part of the nervous system ‘outside’ of the CNS
• Consists of receptors and peripheral nerves that extend from the brain and spinal cord, to and from organs in the body
• Peripheral nerves that connect to the brain are called cranial nerves and those attached to the spinal cord are called spinal nerves
• Nerves are the ‘communication lines’ that link parts of the body to the CNS
• The PNS can be further broken down into functional divisions, which will be covered next