Introduction to the CNS

Question 1

What are the three categories of brain function in the CNS and give areas of the brain that deal each one

Answer 1

1. Input (perceptual): process of handling data transmitted to CNS from sense organs
   Example: Sensory cortex, Thalamus, reticular formation
2. Processing: Integration of new data and association with existing information (memory) and additional emotional components
   Example: Cerebral cortex, Limbic
3. Output: consequential output following cognitive function: voluntary or homeostatic
   Example: Motor cortex, cerebellum, basal ganglia, medulla, hypothalamus, pituritary

Question 2

What is the cerebral cortex responsible for and how much of the total brain neurone does it make up

Answer 2

1. 90%
2. Abstract though, judgement, memory and interpretation and integration of sensory input
3. Cortical disorders: manifest as intellectual dysfunction

Question 3

What are the parts of the body the cerebral cortex is responsible for managing

Answer 3

1. Toes, ankles, knee
2. Hip, trunk, shoulder, elbow
3. Wrist, fingers and thumb
4. Neck, brow, eye, face, lips, jaw, tongue, swallowing

Question 4

What is the Limbic system responsible for and give an example

Answer 4

1. Application of emotion (feelings) to mental/cognitive function
2. Example: Fear, Love (LIMBIC), Rage, Pleasure

Question 5

What is the shape of the hipocampus

Answer 5

Seahorse

Question 6

What can odours produce in the cortex and limbic system

Answer 6

Strong emotional responses

Long dormant memories

Question 7

Where is the basal ganglia located and what is it responsible for

Answer 7

1. Interconnected nuclei within the cerebrum
2. Responsible for co-ordinating voluntary motor activity between cerebellum and cortex
3. Posture, reaching out arm, not falling

Question 8

What is the basal ganglia divided into

Answer 8

Corpus striatum
Globus pallidus
Substantia nigra

Question 9

What is the role of the thalamus and what can dysfunction of it lead to

Answer 9

1. Role: Thalamus acts as a pre-processor and relays sensory information
2. Dysfunction: Hallucination

Question 10

What is the role of the hypothalamus and what does it control

Answer 10

1. Role: Influences autonomic nervous system (sympathetic and parasympathetic function)
2. Controls satiety, sleep, thermoregulation, sexual appetite

Question 11

What does the brainstem control and its role

Answer 11

1. Contains: visual, auditory and motor centres- not confused with cortical areas that are responsible for higher control
2. Influences CNS input and output: simply acts as relay stations
3. Role: Ascending pathways carry info to brain, descending pathways carry info to periphery

Question 12

What is a psychiatric disorder and give some examples

Answer 12

1. Disorders of mood, thought, behaviour and perception
2. Functional in origin: do not know they have this
3. Examples: Anxiety, depression, mania, schizophrenia

Question 13

What is a neurological disorder and give some examples

Answer 13

1. Disorders of movement, intellect and sensation
2. Primarily “organic”: understand cause of symptoms
3. Examples: Epilepsy, stroke, extrapyramidal disorder, brain tumour, migraine

Question 14

What do the neurones do

Answer 14

Signalling unit in nervous system

Question 15

What do Glial cells do

Answer 15

Transportation of oxygen, mopping up waste, scaffolding

Provides supporting role to neurones

10x more glial cells than neurones

Question 16

What do the dendrites do in a neurone

Answer 16

Receive incoming stimuli from adjacent neurons: basal and apical

Question 17

What does the axon do in a neurone

Answer 17

Initial segment: responsible for firing AP
Myelin Sheath
Nodes of Ranvier

Question 18

What do the nerve terminals do in a neurone

Answer 18

AP triggers cascade to next neurones: presynaptic terminal

Question 19

Give different neurotransmitter systems

Answer 19

Glutamate 50%
GABA: 30%
Amines: dopamine
5-HT
Noradrenaline
Acetylcholine
Neuropeptides

Question 20

What are astrocytes and its functions

Answer 20

1. Capable of division

2. Functions:
Physical support for neurones
Ionic homestasis 
Neurotransmitter uptake
Signalling to neurones
Respond to CNS injury
Interact with capillaries

Question 21

What are oligodendrocytes

Answer 21

Myelinating cells of CNS

Question 22

What is the role of Microgila

Answer 22

1. Clear area of scar tissue but damages healthy area to do so
2. Macrophage like cells that are resident in CNS to act as immune system
3. Responds to CNS inflammation and injury
4. Engulf foreign bodies and contribute to repair and injury

Question 23

What cells in ventricles produce CSF and what is its role

Answer 23

Ependymal cells

Transport nutrients and waste away

Question 24

What cells form the tight junctions and how

Answer 24

Cerebral endothelial cells through several transmembrane proteins

Question 25

What is a tight junction

Answer 25

Seal the paracellular pathway and makes the brain inaccessible for polar molecules unless active transported

Question 26

What does the adherens junction do

Answer 26

Stabilises Cell to cell interactin

Question 27

What are some intracellular and extracellular enzymes that provide metabolic activity

Answer 27

Monoamine Oxidase (MAOI)
Y-glutamyl transpeptidase
Alkaline Phosphatase
Peptidases 
Nucleotides 
Cytochrome P450 enzymes