WEEK 7: Autonomic Nervous System

Question 1

What are the types of GVE fibres?

Answer 1

Pre-ganglionic sympathetic neuron
Post-ganglionic sympathetic neuron
Pre-ganglionic parasympathetic neuron
Post-ganglionic parasympathetic neuron

Question 2

Name and explain the different types of outflow?

Answer 2

Thoracolumbar outflow: Relates to the origin of sympathetic neurons. Neurons arise in thoracic and lumbar regions on the spinal cord
Cranialsacral outflow: relates to the origin of parasympathetic neurons. Neurons arise in the brain stem or in the sacral region of the spinal cord

Question 3

what are the two different neurotransmitters in the ANS

Answer 3

sympathetic division: Noradrenaline (NA)

Parasympathetic division: Acetycholine (ACH)

Question 4

what is hitch-hiking?

Answer 4

this means that nerve fibres can travel along paths already created

Question 5

what is the difference between ACH receptors Nicotinic and Muscarinic receptors?

Answer 5

Nicotinic
-Found in somatic neuromuscular junctions in skeletal muscle
and can also be found in autonomic ganglia at the synapse between preganglionic and
postganglionic neurons in both sympathetic and parasympathetic neurons
- The effect of ACh binding to a nicotinic receptor is always stimulatory

Muscarinic

• Found at parasympathetic postganglionic smooth muscle junctions
• Effect of ACH binding can be excitatory or inhibitory

Question 6

Explain where alpha and beta NE receptors would be found

Answer 6

Alpha
a1 responsible for the sympathetic constriction of blood vessels
a2 inhibits norepinephrine release, inhibits secretion of insulin and promotes blood
clotting

Beta
b1 found predominantly on the heart. NE release on the heart activates b1 receptors and
increases heart rate and strength
b2 found predominantly on the lungs. NE release on the lungs activates b2 receptors
which dilates blood vessels and bronchioles making it easier to breath
b3 stimulates lipolysis by fat cells

Question 7

Explain the origin of the sympathetic trunk

Answer 7

-There is both a left and a right sympathetic trunk that run lateral to the spinal cord

-Sympathetic preganglionic fibres arise from spinal segments T1 through to L2 hence why
it is also referred to as the thoracolumbar division
-
Sympathetic postganglionic fibres can travel from the neck to pelvis

Question 8

what is the difference netween grey and white rami communicans and where are they found?

Answer 8

grey is unmyelinated while white is myelinated

only found in the sympathetic division of the ANS and they extend of the sympathetic trunk

Question 9

what is the importance of the sympathetic trunk?

Answer 9

The sympathetic trunk helps to distribute sympathetic fibres to the whole body as it extends

Question 10

what are the Special sense receptors?

Answer 10

Mechano receptors which detect pressure
 Thermo receptors which detect temperature
 Chemo receptors which detect taste and smell
 Photo receptors which detect light

Question 11

What are the general sensory modalities?

Answer 11

Pain
 Temperature
 Touch
 Pressure

Question 12

what is the main difference between special sensory and general sensory modalities

Answer 12

Special sensory modalities are only found in the head and neck while general sensory modalities are found all over the body

Question 13

Annotate “hearing, sight, balance etc..” diagram

Answer 13

…

Question 14

what causes compression of a spinal nerve and what can be the consequences?

Answer 14

the squeezing of a nerve can be due to trauma, external pressure or a tumour

Compression of a spinal nerve will result in the dermatome and myotome region that the spinal nerve innervates having loss of sensation and loss of movement