Nerves, The Heart And Pericardium

Question 1

What are the 2 types of nerves and what do they innervate?

Answer 1

Somatic = skin and skeletal muscle
E.g. intercostal nerves, phrenic nerves

Autonomic (visceral) = organs, smooth muscle, glands

Question 2

Where are the intercostal nerves found?

Answer 2

T1-11

Question 3

Why are intercostal nerves described as segmental?

Answer 3

Each pair of nerves supplies a single segment of the body e.g. a vertebrae, skeletal muscle and skin

Question 4

Describe the structure of a segmental spinal nerve

Answer 4

Anterior root = ventral = motor
Posterior root = dorsal =sensory

This splits into the:
Posterior ramus = motor fibres to erector spines complex and sensory to skin above theses muscles
Anterior ramus = supplies muscle right to front

Question 5

What are dermatomes and myotomes?

Answer 5

Are of skin or muscle that single nerve stimulates

Question 6

How do we get referred pain?

Answer 6

From the phrenic nerves, pain in the diaphragm region is felt by the body at the neck at C3,4,5

Question 7

What are the 2 types of motor neurones in the autonomic nervous system?

Answer 7

Pre ganglionic = cell body in brain/spinal cord run to autonomic ganglia where they synapse with post ganglionic
Post ganglionic = to target organ

This is good as few cell bodies BUT less precise

Question 8

Where are the sympathetic nerves found?

Answer 8

T1 -L2

Question 9

Describe the arrangement of sympathetic nerves?

Answer 9

Fibres form a paravertebral ganglion where pre and post ganglionic synapse

1. nerve cell body in the spinal cord
   if impulse goes to:
2. body wall = synapse in chain
3. viscera = go through chain and synapse somewhere else (pre vertebral column)= in the midline

Question 10

What is the rami communicantes?

Answer 10

Join the spinal nerves to sympathetic ganglia

Question 11

Which fibres form the white ramus comminucans?

Answer 11

Pre ganglionic leaving spinal cord form the white ramus communicans as they are myelinated
Post = grey

Question 12

What is the paravertebral chain?

Answer 12

Paravertebral ganglia joined together up and down the spinal cord

Question 13

what is the significance of the paravertebral ganglia and the where the sympathetic start?

Answer 13

the paravertebral ganglia extends more than T1-L2

Question 14

what are splanchnic nerves?

Answer 14

sympathetic nerves that reach T5-T12

Question 15

how is are parasympathetic nerves different to sympathetic?

Answer 15

they only go to viscera not somatic as well

they all go to the vagus nerve

Question 16

where are the right and left vagus found?

Answer 16

right = posterior to SVC 
left = crosses aortic arch

Question 17

where are the 4 heart valves found?

Answer 17

aortic = second ICS right
pulmonary= second ICS left
tricuspid = fifth ICS sternum 
mitral = firth ICS apex beat

Question 18

name the layers of the pericardium

Answer 18

fibrous

serous = parietal (lines fibrous) + visceral (lines heart)

Question 19

what are the 2 pericardial sinuses?

Answer 19

oblique = reflection of pulmonary veins
transverse = separate arteries form vein

Question 20

what is the hole between the right and left atrium?

Answer 20

fossa ovalis

Question 21

how many aortic sinuses are there?

Answer 21

3

in 2 there are holes where coronary arteries emerge from