MNSR 16 - Nervous system: Autonomic Nervous System, Cranial Nerves, Brain

Question 1

What is a receptor?

Answer 1

A receptor is a protein molecule that receives and responds to a neurotransmitter, hormone, or other substance. There are two types of receptors:

1. Adrenergic: binds and responds to adrenaline
2. Cholinergic: Binds and responds to ACh

Question 2

Where does adrenaline come from?

Answer 2

Adrenaline is secreted by:

1. postganglionic neurons in the Sympathetic Nervous System
2. Adrenal gland

Question 3

What are the two classes of adrenoreceptors?

Answer 3

Alpha-adrenoreceptors:
- a1: found in smooth muscle, causes vasoconstriction of blood vessels, relaxation of GIT, and pale appearance
- a2: found in presynaptic and postsynaptic terminals, mediate synaptic transmission
Beta-adrenoreceptors:
- b1: found in heart and cerebral cortex, increase rate and force of heart contractions
- b2: found in lungs, smooth muscle, and cerebellum, cause bronchiole dilation, relaxation of smooth muscle
- b3: found in adipose tissue, causes the breakdown of fat
(Noradrenaline stimulates mainly alpha adrenoreceptors, a slight effect on beta adrenoreceptors)

Question 4

What are the two types of AChRs?

Answer 4

1. Nicotinic AChr: bind to nicotine, located in the CNS, NMJ, Presynaptic terminal in ganglia
2. Muscarinic AChr: bind to muscarine, located between the postganglionic neuron and innervated tissue

Question 5

List the groups of cranial nerves.

Answer 5

1. Special Sensory
   - I Olfactory
   - II Optic
   - VIII Auditory
2. Doral Root
   - V Trigeminal
   - VII Facial
   - IX Glossopharyngeal
   - X Vagus
   - XI Accessory
3. Ventral Root
   - III Oculomotor
   - IV Trochlear
   - VI Abducens
   - XII Hypoglossal

Question 6

Explain the morphology of the brain.

Answer 6

1. Cerebral Cortex
   - Frontal (coordination and planning)
   - Parietal (sensory info)
   - Temporal (Auditory)
   - Occipital (Visual)
2. Brainstem
   - midbrain (motor function)
   - pons (relays sensory info between the cerebellum and cerebrum)
   - medulla oblongata (controls autonomic function)
3. Cerebellum (fine tunes movement, motor output, and sensory perception)

Question 7

What are the names of the four regions developed after four weeks?

Answer 7

1. Prosencephalon
2. Mesencephalon
3. Rhombencephalon
4. Spinal Cord

Question 8

What are neuroglia?

Answer 8

A class of cells in the brain and spinal cord that form a supporting structure for the neurons and provide them insulation. There are two types:

1. Macroglia
   - astrocyte (most abundant, most prominent in grey matter)
   - oligodendrocyte (most prominent in white matter)
   - radial glia
   - ependymal cell
   - Schwann cell
   - Satellite cell
2. Microglia