Organisation of Nervous System (Weeks 1 - 3)

Question 1

Functions of brain stem

Answer 1

1. sensation & motor control of head, neck & taste
2. receives info: hearing, balance, taste
3. reflexes of autonomic nervous system
4. asc. & desc. info to other divisions of CNS
5. regulation of alertness & arousal

Question 2

Parts of brain stem

Answer 2

Medulla
Pons
Midbrain

Question 3

Position of medulla

Answer 3

Caudal brainstem

Question 4

Contents/role of medulla

Answer 4

Neuronal groups: regulation of

• blood pressure
• respiration
• taste
• hearing
• balance
• control of mm. in head & neck

Question 5

Position of pons

Answer 5

Ventral brainstem, rostral to medulla

Question 6

Role of pons

Answer 6

Ventral: relaying info about movement & sensation

Dorsal: breathing, taste & sleep

Question 7

Contents/role of midbrain

Answer 7

Nuclei: linkage between components of motor system - cerebellum, basal ganglia & cerebral hemispheres
Components of auditory & visual systems

Question 8

Role of cerebellum

Answer 8

Maintaining posture &co-ordinating head, eye & arm movements - receives that information from spinal cord, inner ear & cerebral cortex.

Minute regulation of motor output & learning motor skills

Language & cognitive functions

Question 9

Contents of diencephalon

Answer 9

Thalamus

Hypothalamus

Question 10

Role of thalamus

Answer 10

Gateway for sensory info from periphery - determines which info reaches cortex.

Connects cerebellum & basal ganglia with regions of cortex (cognition & mvt).

Attention & consciousness

Question 11

Role of hypothalamus

Answer 11

Regulation of homeostasis & reproductive behaviours

Influences behaviour (highly connected with CNS)

Question 12

Contents of cerebral hemispheres

Answer 12

Cerebral cortex (& white matter)
Basal ganglia
Amygdala
Hippocampal formation

Question 13

Role of somatic sensory division

Answer 13

Sensory input from periphery to CNS

Includes visceral sensory division: from viscera (afferent component of ANS)

Question 14

Sympathetic nervous system

Answer 14

Fight or flight component of ANS

Question 15

Parasympathetic nervous system

Answer 15

Rest & digest component of ANS

Question 16

Most sensory cells are…

Answer 16

Bipolar neurons

Question 17

3 types of multipolar neurons

Answer 17

Motor neurons
Pyramidal neurons
Purkinje cells

Question 18

Microglia

Answer 18

Phagocytes
Active after injury, infection, disease

Regulate apoptosis during development
Regulate neurogenesis
Maintain homeostasis

Question 19

3 types of macroglia

Answer 19

Oligodendrocytes
Schwann cells
Astrocytes

Question 20

Oligodendrocytes

Answer 20

Form myelin sheath in CNS

Absorb chemical neural products, release chemicals that the neuron absorbs

Question 21

Schwann cells

Answer 21

Form myelin sheaths in PNS (wraps itself around the axon)

Absorb chemical neural products, release chemicals that the neuron absorbs

Question 22

Astrocytes

Answer 22

Irregular shape
Most abundant
Either protoplasmic or fibrous
Contribute to formation of blood-brain barrier

Insulate neuronal groups
Regulate extracellular K+ conc.
Remove neurotransmitters from synaptic cleft
Nourish neurons through release of growth factors

Question 23

Difference between protoplasmic & fibrous astrocytes

Answer 23

Protoplasmic - found in grey matter. Sheet-like processes

Fibrous - found in white matter. Long, fine processes

Question 24

Where do brain tumours come from?

Answer 24

Normally glial cells (gliomas), because neurons don’t divide during life.

Question 25

What is MS?

Answer 25

Disease in which oligodendrocytes (& myelin sheaths) deteriorate.
Disrupts nerve conduction

Question 26

Action potential (definition)

Answer 26

Rapid & transient fluctuations in membrane voltage that propagate from the cell body down the axon towards the synapse, where it initiates neurotransmitter release

Question 27

Passive ion channel

Answer 27

Always open, bidirectional
Flow follows electrochemical gradient
NB: can’t produce action potential

Question 28

How is membrane potential maintained?

Answer 28

Cells pump out Na+ ions using ATP-dependent “Na-K-ATPase”

Question 29

Voltage-gated ion channel

Answer 29

Responsible for generating action potential.
Open at threshold

3 states: closed, open, inactive

Question 30

Refractive period

Answer 30

Voltage-gated ion channel remains inactive after opening.