The Organization of the Central Nervous System

Question 1

What is Proprioceptive Perception

Answer 1

Information about the position of the body. This is how we can touch our nose or ears even with our eyes closed.

Question 2

What is Rostral-Caudal axis?

Answer 2

Rostral = Beak and Caudal = Tail - The axis from the front side to back side in animal like a bird

Question 3

What is Dorsal-Ventral Axis?

Answer 3

Dorsal - The top part of the view.
Ventral - The bottom part of the view.
Example, if you are looking at a frog, then, its back is dorsal and its stomach is ventral

Question 4

What is Medial-Lateral Axis?

Answer 4

Medial is closer to the midline and lateral is towards the edges.

Question 5

What are the main components of nervous system?

Answer 5

Central Nervous System = Brain and Spinal Cord

Peripheral Nervous System = Somatic (voluntary movement) and Autonomic (involuntary processes)

Question 6

Medulla and its main functions

Answer 6

Caudal part of the brain - Main functions include respiration and blood pressure regulation. It also has pathways that mediate taste, hearing, maintaining balance, and control of neck and facial muscles

Part of the brain stem

Question 7

Pons and its main functions

Answer 7

Located rostral to the medulla

• Ventral part has a projection and has important role in information relay from cerebral cortex to cerebellum about motor movements
• Dorsal part participates in sleep, respiration and taste

Part of brain stem

Question 8

Midbrain and its main functions

Answer 8

Smallest part of the brain stem - rostral to pons
Plays important role in communication of motor system between cerebral cortex, basal ganglia, and cerebellum
Substantia nigra provides important input related to voluntary movement and damage to the dopaminergic neurons in this region is responsible for motor disturbances in Parkinson’s disease

Question 9

What are the 5 distinct functions of brain stem?

Answer 9

1. Mediates sensory information from head, neck and face to 12 cranial nerves (analogous to 31 spinal nerves)
2. Site of entry for specialized senses like hearing, balance, and taste.
3. Parasympathetic regulation of blood pressure, increased peristalsis of the gut, and constriction of the pupils
4. Ascending and descending pathways for sensory and motor information to the CNS
5. Reticular formation regulates alertness

Question 10

What are the components of autonomous nervous system?

Answer 10

Sympathetic Nervous System = Involuntary Stress Response mechanisms such as increased heart rate, elevated blood pressure, dilation of pupils, etc in response to a stressor

Parasympathetic Nervous System = Involuntary regulation of processes to bring heart rate down, etc.

These two systems are antagonistic and work in opposition to each other. Sympathetic is like gas pedal and Parasympathetic is like break pedal in a car :-)

Question 11

Cerebellum and its main functions

Answer 11

Division with most number of neurons than any other division in the brain including the cerebral hemispheres.

Not only is important in maintaining balance and movement but also participates in language and other cognitive functions.

Receives somatic information from spinal cord, vestibular information from ear, and motor information from cerebral cortex.

Question 12

What are the 2 main sub-divisions of diencephalon?

Answer 12

Thalamus and Hypothalamus

Question 13

What is the main role of thalamus

Answer 13

It was originally thought of as a relay station for sensory information going to neocortex. Now it is also known that it decides which information is sent to neocortex.

Question 14

What are the main functions of hypothalamus?

Answer 14

Regulates homeostasis and several reproductive behaviors

Essential component of the motivational system

Regulates circadian rhythms via superchiasmatic nucleus

Question 15

What are the major parts of cerebral hemispheres?

Answer 15

Cerebral cortex, white matter, amygdala, and basal ganglia, and hippocampal formation

Question 16

What are the main functions of cerebral hemispheres?

Answer 16

Perception, motor functions, and cognition including memory and emotion

Question 17

What is corpus collosum?

Answer 17

The commissure fibers (axons connecting laterally) that connect the two hemispheres of the brain.

Question 18

What is a neural map?

Answer 18

The topographically successive arrangement of neurons relative to the physiology of the sensory system.

Question 19

What are decussations?

Answer 19

The action of crossing (as of nerve fibers) especially in the form of an X

Question 20

What are the 6 layers of neocortex

Answer 20

1. Molecular Layer
2. External granule cell layer
3. External pyramidal cell layer
4. Internal granule cell layer
5. Internal pyramidal cell layer
6. Multiform layer

Question 21

Name 3 stains used in neocortex region

Answer 21

1. Golgi Stain
2. Nissl Stain
3. Weigert Stain

Question 22

What are axosomatic synapses?

Answer 22

Synapses that terminate on the target cell body

Question 23

What are axo-axonic synapses?

Answer 23

The axons terminate exclusively on the axons of the target cells

Question 24

What are the 3 main subcortical regions?

Answer 24

1. Basal Ganglia
2. Hippocampal Formation
3. Amygdala

These regulate the cortical activity

Question 25

What are the 2 main types of neurons?

Answer 25

1. Principal (projection) neurons

2. Interneurons