08 25 2014 organization of the Nervous System

Question 1

What is the basic division of the CNS?

Answer 1

1. Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)

Question 2

What composes the prosencephalon?

Answer 2

= forebrain

1. Telencephalon
       cerebral hemispheres
       cerebral cortex
       subcortical white matter
       Basal ganglion
       Basal forebrain

2. Dicephalon
   Thalamus
   hypothalamus
   Epithalamus

Question 3

Mesencephalon?

Answer 3

= midbrain

Cerebral peduncles
midbrain tectum
midbrain tegmentum

Question 4

Rhombencephalon

Answer 4

= hind brain

Metencephalon: pons and cerebellum

Myelencephalon: Medulla

Question 5

What segments compose the brainstem?

Answer 5

Midbrain, Pons, and Medulla

Question 6

Medulla

Answer 6

Transition between spinal cord and brainstem

Cranial nerves: 9, 10, 11, 12
-recieves info from taste, scalp, heart and lungs, major blood vessels and digestive system.
- cardiovascular reflex, respiration, and
digestive function.

Regulates body homeostasis:
-HR, Respiration, Swallowing, vasomotor tone, gastric secretions

Related reflexes:
- vomiting, coughing, sneezing, swallowing, gagging.

Question 7

Pons

Answer 7

bridge to cerebellum

Cranial nerves: 5, 6, 7, 8

Balance, localizing sound, coordinating eye movements, and facial expression

reflexes: eye movements and jaw jerk

Question 8

Midbrain

Answer 8

top of brainstem (aka mesencephalon)

Cranial nerves: 3, 4

Control orienting to sound, visual reflexes, motor control.

Projections to cortex: (Dopamine projections)

• Substntia Nigra – control movements
  - defect = Parkinson’s Disease
• Ventral segmental area – reward system
  - addiction pathway
• orientation reflexes

Question 9

Frontal Lobe of cortex

  - function?
  - Location?

Answer 9

Planning, organizing, control, controlling behavior

Located from front of brain –> central sulcus
Separated from temporal via Sylvian fissure

Question 10

Parietal Lobe of cortex

  - function?
  - Location?

Answer 10

Sensory perception of self and world (know where you are and where you are in your environment)

From central sulcus –> Parieto-occipital sulcus (found in the medial aspect of brain)

Question 11

Occipital Lobe of cortex

-function?

Answer 11

Visual processing

Question 12

Temporal Lobe of cortex

-function?

Answer 12

Auditory processing (superior)
Visual processing (middle)
Memory processing (medial)

Question 13

Limbic Lobe of cortex

-Function?

Answer 13

Emotional processing and memory consolidation

Question 14

Layer 1 of cortex

Answer 14

Molecular layer

Dendrites and axons from deeper layers

Question 15

Layer 2 of cortex

Answer 15

Small pyramidal layer

Cortical-cortical connections

Question 16

Layer 3 of cortex

Answer 16

Medium pyramidal layer

Cortical-cortical connections

Question 17

Layer 4 of cortex

Answer 17

Granular layer

Receives inputs from thalamus

Question 18

Layer 5 of cortex

Answer 18

Large pyramidal layer

Sends outputs to subcortical structures (other than thalamus)
-brain stem, spinal cord, basal ganglion

Question 19

Layer 6 of cortex

Answer 19

Polymorphic layer

Sends outputs to thalamus.

Question 20

Thalamus

Answer 20

major relay station for all inputs heading into cortex.

A cluster of nuclei that have specific functions. Reticular and intralaminar nuclei receive from the reticular activating system

-projections into cortex are called thalamocortical radiations

Also regulates states of sleep and wakefulness

Question 21

Reticular formation

Answer 21

mass of interwoven cells and synapses that go through the entire brainstem
-project into cortical ascending and several descending projections to the spinal cord

Question 22

Reticular Activating system

Answer 22

Rostral projections from pons and midbrain
- Norepinephrine = role in wake/sleep states

• If this formation is affected, people will go into a coma and you can’t wake them up from it.
• modulates forebrain activity

Question 23

Caudal Reticular formation

Answer 23

Medulla

• respiratory rhythms
• blood pressure
• digestions

Reflexes: facial expression, gag, yawn, swallowing, vomit.

-premotor coordination of lower somatic and visceral motor neuron pools