Chapter 1 - Studying the Nervous System

Question 1

What are gap junctions, and why would Camillo Golgi care about them?

Answer 1

Gap junctions are the rare intercellular continuities between some neurons, these neurons do not communicate through with each other through neurotransmitters, but instead allow the current flow to diffuse through the gap junction and continue in the neighboring cell. Camilio Golgi was an Italian pathologist who championed a “retikular theory” of nerve cell communication, of which nerve cells communicate because they are connected through protoplasmic links.

Question 2

The cells of the nervous system can broadly be divided into two types. Which?

Answer 2

Neurons and Glia.

Question 3

Explain convergence.

Answer 3

The number of inputs to a single neuron.

Question 4

Explain divergence

Answer 4

The number of targets innervated by any one neuron.

Question 5

What is another word for dendritic branches?

Answer 5

Dendritic processes.

Question 6

Divide neurons into two types based on their length and function.

Answer 6

Short interneurons and projection neurons.

Question 7

Which four types of glial cells are there?

Answer 7

Astrocytes, oligodendrocytes , microglial cells and glial stem cells.

Question 8

What are the functions of astrocytes?

Answer 8

Cells that maintain the chemical environment, and have stem cell properties.

Question 9

What are the functions of oligodendrocytes?

Answer 9

They are responsible for the myelination of the CNS axons. They also have stem cell properties.

Question 10

What are the functions of microglial cells?

Answer 10

They share properties with macrophages found in other tissues. They remove cellular debris from sites of injury or normal cells turnover. They also secrete signaling molecules that modulate local inflammation and influence cell survival or death.

Question 11

What are the functions of glial stem cells?

Answer 11

Can generate additional precursors or differentiated glia, and in some cases: neurons.

Question 12

Where in the brain can you find glial stem cells?

Answer 12

Astrocytes in the subventricular zone, and oligodendroglial precursors scattered throughout the white matter.

Question 13

What is the neuropil?

Answer 13

The region between nerve cell bodies.

Question 14

Neurons carrying information from the periphery to the brain are called…

Answer 14

afferent neurons.

Question 15

Neurons carrying information from the brain to the periphery are called…

Answer 15

efferent neurons.

Question 16

What is another name for the “knee-jerk” reflex?

Answer 16

The myotatic reflex.

Question 17

Explain how the myotatic reflex works. You need to mention the following: the muscles involved, and be able to draw the neurons involved and how they are connected.

Answer 17

Score yourself according to the picture on p. 12

Question 18

What is meant by a neurons receptive field?

Answer 18

The region in sensory space (e.g. the body surface) within which a specific stimulus elicits action potential response.

Question 19

The peripheral nervous system (PNS) consist of sensory and motor components. The motor components can be divided into two parts. Which?

Answer 19

1. Somatic motor system

2. Visceral motor system/Autonomic motor divison.

Question 20

What is the somatic motor system?

Answer 20

The motor axons that connect the brain and spinal cord to skeletal muscles make up the somatic motor division. This includes the cranial nerves and the spinal nerves.

Question 21

What is the visceral motor system?

Answer 21

The cells and axons that innervate smooth muscles, cardiac muscle, and glands make up the visceral or autonomic motor division.

Question 22

The autonomic division of the PNS can be further divided into..

Answer 22

1. The sympathetic division
2. The parasympathetic division
3. The enteric system

Question 23

What is the sympathetic division of the autonomic nervous system?

Answer 23

The sympathetic division of the autonomic nervous system has ganglia that lie along or in front of the vertebral column and send their axons to a variety of peripheral targets.

Question 24

What is the parasympathetic division of the autonomic nervous system?

Answer 24

The parasympathetic division has ganglia that are found within or adjacent to the organs they innervate.

Question 25

What is the enteric division of the autonomic nervous system?

Answer 25

It is made up of small ganglia as well as individual neurons scattered throughout the wall of the gut. These neurons influence gastric motility and secretion.

Question 26

Where do we find the neurons that originate the parasympathetic component of the autonomic nervous system?

Answer 26

The neurons that originate the parasympathetic component are found in the spinal cord and brainstem. Specifically cranial nerves C, IC, VII, III and sacral spinal nerves.

Question 27

Define the cortex.

Answer 27

The outer covering of the cerebral hemisphere is known as the cortex. The cortex has a high degree of interconnectivity.