Nerves

Question 1

Cerebral Hemispheres (clockwise)

Answer 1

Frontal, parietal (proprioception), occipital, temporal (sound and speech recognition)

Question 2

Folds in white matter

Answer 2

Gyri - ridges

Sulci - Valleys

Question 3

Brainstem Anatomy (descending)

Answer 3

• midbrain
• pons
• medulla

Question 4

Cerebellum

Answer 4

• hindbrain attached to the brainstem

- used for fine-tuning motor function and aiding balanced and posture.

Question 5

Nerve Cell Types

Answer 5

• unipolar
• psudeounipolar
• bipolar
• multipolar (only one axon, the rest are dendrites
• Pyramidal
• Purkinje (GABA neurones found in the cerebellum)
• Golgi (GABA neurones found in the cerebellum)

Question 6

Classic Structure

Answer 6

Soma (nucleus within), single axon (from soma at axon hillock), neurofilaments and then dendrites

Question 7

Neurofilament Function

Answer 7

type of intermediate filament that provides structural support and transport

Question 8

Astrocyte Info

Answer 8

• neuroglia
• outnumber neuronal cells in CNA
• not excitable
• can proliferate
• most abundant cell in mammalian brain

Question 9

Astrocyte Function

Answer 9

• structural cells as act as ‘glue’
• repair by providing nutrients for neuronal cells
• facultative macrophages (can become one if necessary)
• Homeostasis vie clearing neurotransmitter and other substances released in CNS

Question 10

Oligodendrocyte Function

Answer 10

Forms the myelin within the CNS. One oligodendrocyte can myelinate many axons.

Question 11

Difference between Oligodendrocytes and Astrocytes

Answer 11

• oligodendrocytes are smaller
• oligodendrocytes have a denser cytoplasm and nucleus
• oligodendrocytes do not have intermediate filaments and glycogen in the cytoplasm

Question 12

Schwann Cell Info

Answer 12

• produce myelin for peripheral nerves

- one schwann cell myelinates one axon

Question 13

Microglial Cell Function

Answer 13

Immune cells of the CNS. Similar to macrophages

Question 14

Ependymal Cell function

Answer 14

• Epithelial cells of the CNS. They line fluid filled ventricles (CSF). Regulate production/movement of CSF

Question 15

Neurotransmission Major Ions

Answer 15

• Na+
• K+
• Ca2+
• Cl-

Question 16

Normal Ion Values Intracellularly

Answer 16

K+ = 150mM
Na+ = 10mM
Ca2+ = 0.0001mM
Cl- = 5mM

Question 17

Normal Ion Values Extracellularly

Answer 17

K+ = 4mM
Na+ = 140mM
Ca2+ = 2mM
Cl- = 120mM

Question 18

Action Potential Order

Answer 18

1) Resting membrane potential = -90mV–40mV
2) at -40mV, VGSC open leading to Na+ influx
3) Depolarisation occurs till VGKC open and efflux of K+ occurs (therefore repolarisation)
4) membrane returns to resting potential after hyperpolarisation
5) Na-K+ pump restore resting potential

Question 19

Saltatory Conduction

Answer 19

Myelin prevents depolarisation apart from at the Nodes of Ranvier (these have a dense conc of VGSC and VGKC). Action potential jumps

Question 20

Synapse Occurences

Answer 20

1) AP propagated towards synapse
2) AP cause VGCC’s to open allowing Ca2+ influx and therefore vesicle exocytosis
3) the NT binds to post-synaptic receptors which modulate post-synaptic activity
4) NT dissociates from receptor and is either metabolised by enzymes in synpatic cleft or recycled by transporter proteins