Week 2 lecture

Question 1

What is the CNS and PNS comprised of?

Answer 1

CNS –> brain and spinal cord
PNS –> cranial and spinal nerves

Question 2

Glia are supporting cells. What are some examples of glial cells?

Answer 2

Oligodendrocytes –> myelinate CNS axons
Neurolemmocytes (Schwann cells) –> myelinate PNS axons
Astrocytes –> part of the BBB
Ependymal cells –> filter blood to produce CSF
Microglia –> immune cells
Polydendrocytes –> stem cells

Question 3

What is the medial, lateral and flocculonodular lobe of the cerebellum responsible for?

Answer 3

Medial - Spinocerebellum –> proper execution of coordinated movements

Lateral - Cerebrocerebellum –> planning coordinated, properly times movement sequences

Floculonodular lobe - Vestibulocerebellum –> coordinated balance and eye movement

Question 4

What is composed of the autonomic division?

Answer 4

Cranial nerves (parasympathetic: 3, 7, 9 and 10) –> rest and digest
And
Sympathetic nerves –> fight or flight

Question 5

Where are the cell bodies of pre-ganglionic sympathetic neurons located in the thorax?

Answer 5

They are in the intermediolateral coloumn in the spinal cord grey matter T1 - L2

• contain sympathetic cell bodies of post-ganglia

Question 6

Where are the sympathetic and parasympathetic fibres of The autonomic ganglia in the abdomen and pelvis arising from?

Answer 6

Sympathetic arises –> T1 - L2

Parasympathetic –> X and S2-S4

Question 7

What information do somatic nerves carry?

Answer 7

general sensory (afferent) and
general motor (efferent)

Question 8

Cones are tuned to particular wavelengths. Once light is absorbed, there is?

Answer 8

Once light is absorbed there is neural excitation. The photoreceptors do not transmit any colour information

Question 9

The Purkinje shift occurs as we move from …dominated to …dominated light levels

Answer 9

The Purkinje shift occurs as we move from rod dominated to cone dominated light levels

Question 10

The macular and lens filter how much percentage of blue?

Answer 10

50% of blue

Question 11

What functions do horizontal and bipolar cells play in colour perception?

Answer 11

Horizontal cells make contact with surround centre of the cell

Bipolar cells make contact with centre of the cones

If the cones elicit equal stimulus in the centre and surround –> horizontal cells inhibit the bipolar output

If the cones elicit equal stimulus in the centre –> horizontal cells promote bipolar output

Question 12

What is a disadvantage of the centre and surround contact principle?

Answer 12

Horizontal cells contact R, G and B cones in the surround and some that contact many
–>
the colour centre surround inputs and outputs can be varied across the retina

Question 13

Red / greenprojects to parvocellular layers in LGN. Which layer do these relay into V1?

Answer 13

Layer Iv and then project up to layer III

Question 14

How does an autoimmune disease occur?

Answer 14

Autoimmune disease occur when the immune system mistakenly attacks the body’s own tissues.

Question 15

Why is tolerance necessary?

Answer 15

Tolerance is necessary to prevent autoimmune reactions, and its breakdown can lead to autoimmune diseases.

Question 16

What are examples of tolerance breakdown

Answer 16

In tolerance breakdown, mechanisms such as failure to delete autoreactive lymphocytes, molecular mimicry, abnormal self-antigen presentation, epitope spreading, and polyclonal lymphocyte activation can occur.

This breakdown can lead to autoimmune responses and the loss of immune tolerance towards self-antigens. Aberrant expression of major histocompatibility complex class II molecules, coupling of self and non-self antigens, and overproduction of self-antigens are some factors contributing to tolerance breakdown.

Question 17

The immune system employs carious mechanisms to distinguish between self and non-self antigens, but sometimes these mechanisms fail. How?

Answer 17

The immune system can fail to distinguish between self and non-self antigens due to central tolerance failure, where autoreactive lymphocytes are not deleted during development. Additionally, abnormal presentation of self-antigens, molecular mimicry, and epitope spreading can lead to immune system confusion. The use of the same receptors by T and B cells to recognize both self and non-self antigens can also contribute to this failure in discrimination.