Nervous System: Organization of the Human Nervous System (HY)

Question 1

what are the three types of nerve cells in the nervous system and what does each do?

Answer 1

1. sensory (afferent) neurons: transmit signals from receptors to spinal cord and brain
2. motor (efferent) neurons: transmit motor signals from brain and spinal cord to muscles and glands
3. interneurons: found between other neurons, linked to reflexive behavior

Question 2

what are supraspinal circuits?

Answer 2

circuits that involve input from brain/brainstem

Question 3

what is the difference between white matter and gray matter?

Answer 3

white matter: axons encased in myelin sheaths (myelin is white)
gray matter: unmyelinated cell bodies and dendrites

Question 4

what are the four divisions of the spinal cord from top to bottom?

Answer 4

CTLs

1. cervical
2. thoracic
3. lumbar
4. sacral

Question 5

what structure protects the spinal cord?

Answer 5

vertebral column

Question 6

How is the order of white and gray matter different in the brain and the spinal cord?

Answer 6

In the brain, the white matter lies deeper than the grey matter. But in the spine, the gray matter lies deeper than the white matter

Question 7

Sensory neurons ____ the dorsal side of the spinal cord, and their cell bodies are found in the ____ ____ ____. Motor neurons ___ the ventral/front side of the spinal cord.

Answer 7

sensory neurons enter the dorsal side
sensory cell bodies are found in the dorsal root ganglia
motor neurons exist spinal cord ventrally

Question 8

what are the two parts of the peripheral nervous system?

Answer 8

1. somatic nervous system

2. autonomic nervous system

Question 9

what does the somatic nervous system do?

Answer 9

sensory and motor neurons distributed in skins, muscles, and joints

Question 10

what does the autonomic nervous system do?

Answer 10

regulates involuntary/automatic functions, like heartbeat, respiration, digestion, and glandular secretions

Question 11

what is the central nervous system made of?

Answer 11

brain and spine

Question 12

what is the peripheral nervous system made of?

Answer 12

nerve tissue and fibers outside brain and spineal cord

Question 13

what are the preganglionic and postganglionic neurons?

Answer 13

the two neurons involved in the autonomic nervous system signalling from spinal cord to target tissue (only one motor neuron, no synapse involved in somatic nervous system signalling from spinal cord to muscle)

soma of preganglionic neuron in the central nervous system, and its axon connects to the postganglionic neuron in the autonomic nervous system, thus affecting the target tissue.

Question 14

what are the two divisions of the autonomic nervous system?

Answer 14

1. sympathetic nervous system

2. parasympathetic nervous system

Question 15

How are the sympathetic and parasympathetic nervous systems different in function?

Answer 15

parasympathetic nervous system conserves energy, increases digestion, reduces heart rate, constricts lungs.
sympathetic nervous system responds to stress, increases heart rate, increases blood glucose, relaxes lungs, dilates eyes

Question 16

what hormone is involved in the parasympathetic nervous system response?

Answer 16

acetylcholine is released from both preganglionic and postganglionic neurons

Question 17

what hormones are released from the preganglionic and postganglionic neurons in the sypatheitc nervous system response? what hormone is released into the blood stream?

Answer 17

preganglionic: release acetylcholine
postganglionic: release norepinephrine
blood stream: epinephrine

Question 18

What are reflex arcs? what are the two types?

Answer 18

neural circuits that control reflexive behavior

1. monosynaptic reflex arc
2. polysynaptic reflex arc

Question 19

What is the difference between a monosynaptic reflex arc and a polysynaptic reflex arc? give an example of each

Answer 19

Monosynaptic reflex arc involves one synapse between the presynaptic sensory neuron and the postsynaptic motor neuron (ex. knee-jerk reflex)

Polysynaptic reflex arc involves at least one interneuron between the sensory neuron and the motor neuron (ex. withdrawal reflex after stepping on nail; interneuron between sensory neuron and motor neuron of opposite stabilizing leg)

Question 20

the vagus nerve is involved in which part of the nervous system?

Answer 20

parasympathetic nervous system

peripheral nervous system –> autonomic nervous system –> parasympathetic nervous system