Nerve

Question 1

Name the four lobes of the brain

Answer 1

Frontal (front)
Occipital (back)
Temporal (temples)
Parietal ( middle)

Question 2

What are the ridges and valleys of the brain called?

Answer 2

Ridges – Gyri, Valleys - Sulci

Question 3

What are the three parts of the brainstem?

Answer 3

Midbrain – Pons - Medulla

Question 4

What is the cerebellum responsible for?

Answer 4

Fine tuning motor functions

Question 5

What are the four broad types of cells in the nervous system? (Named based on their appearance)

Answer 5

Unipolar: one axonal projection
Pseudounipolar: a single projection that splits into two
Bipolar: two projections
Multipolar: numerous projections

there is always only one AXON
the other projection is dendrites

Question 6

What are the three types of multipolar cells?

Answer 6

Pyramidal : pyramid shaped
Golgi : cerebellum
Purkinje : cerebellum

Question 7

What are the three main parts of a neurone?

Answer 7

Soma (cell body), axon (only one), dendrites (numerous)

Question 8

What is the difference between axons and dendrites?

Answer 8

Axons are myelinated and dendrites are not

There is only one axon but there are many dendrites

Question 9

What are astrocytes and what do they do?

Answer 9

astrocytes are very abundant and able to proliferate

Astrocytes are glial cells that have these functions:

• Facultative macrophages (turn into macrophages when they need to)
• Repair (provide nutrients for repair of neuronal cells)
• Homeostasis (mop up neurotransmitter and other substances released by the CNS)

Question 10

What do oligodendrocytes do?

Answer 10

They myelinate many axons in the CNS

Question 11

What are some differences between oligodendrocytes and astrocytes?

Answer 11

Oligodendrocytes are:
Smaller
Denser cytoplasm and nucleus
Absence of intermediate filaments and glycogen in the cytoplasm

Question 12

What do microglial cells do?

Answer 12

They are the immune cells of the CNS

Question 13

What do ependymal cells do?

Answer 13

the epithelial cell that lines the CSF vesicles and regulates production

Question 14

What is the usual resting membrane potential?

how is it maintained ?

Answer 14

Between -40 and -90mV

the membrane is impermeable to ions so it is maintained by channels and pumps

Question 15

What are the intracellular and extracellular concentrations of the four main ions involved in action potentials?

Answer 15

Na+ - inside: 10 outside: 140
K+ - inside: 150 outside: 4
Cl- - inside: 5 outside: 120
Ca2+ - inside: 0.1 outside: 2

Question 16

What is saltatory conduction?

Answer 16

Action potentials jump between adjacent nodes of ranvier (instead of cable conduction) and so it speeds up action potentials

Question 17

what do Schwann cells do?

Answer 17

they only myelinate one section of the axon

Question 18

how do action potentials work?

Answer 18

• at the RMP VGSC and VGKC are closed and the membrane is impermeable
• change in membrane leads to depolarization to -40 mV and VGSC opening causing influx and the full depolarisation to +40mV
• at this points VGSC close and VGKC open
• this K+ efflex leads to the hyperpolarisation of the cell

Question 19

how does repolarisation happen?

Answer 19

• the sodium-potassium pump uses ATP to move 3Na out and 2 K in
• this causes the potential to reduce down again

Question 20

what is synaptic transmission?

Answer 20

this is when action potentials open the VGCC causing a Ca2+ influx which leads to exocytosis of the vesicles so the neurotransmitters are released ad bing to the post synaptic membrane