nerves of the thorax and coronary vessels

Question 1

where does the right coronary artery originate from?

Answer 1

• originates from right aortic sinus

Question 2

where does the left coronary artery originate from?

Answer 2

• originates from left aortic sinus

Question 3

what is the positioning of the pulmonary artery and the aorta?

Answer 3

the pulmonary artery is anterior to the aorta

Question 4

what are the main branches of the coronary arteries on the right?

Answer 4

• •Sino-atrial nodal artery
• •Right marginal artery
• •Posterior descending artery

Question 5

what are the left main branches of the coronary artery?

Answer 5

• circumflex artery
• left anterior descending

Question 6

learn the coronary arteries :

Answer 6

refer to netters card

Question 7

label the grays anatomy coronary arteries

Answer 7

Question 8

what does the sino atrial node supply?

what does the posterior interventricular branch of the right coronary artery supply?

Answer 8

1. supplies the sino atrial node
2. This mainly supplies the posterior and inferior part of the heart

Question 9

overall what does the right coronary artery supply?

Answer 9

• supplies right atrium, right ventricle, SAN, AVN, •posteroinferior 1/3rd of interventricular septum and some of the posterior part of left ventricle

Question 10

what does the Left anterior descending artery supply?

what does the Circumflex artery supply?

Answer 10

1. . It supplies most of the anterior interventricular septum and the left ventricle

therefore very critical

2. •. The circumflex mainly supplies the left atrium and the posterolateral part of the left ventricle

Question 11

overall what does the left coronary artery supply?

Answer 11

• supplies most of the left atrium, left ventricle, atrioventricular branches, and bundles

Question 12

what are the variations in arteries in the population?

Answer 12

2/3 population are right dominant coronary artery

1/3 of the population are left dominant coronary artery

Question 13

what’s the difference between the left dominant coronary artery and right dominant coronary artery?

Answer 13

right dominant = the posterior descending comes off the right dominant therefore the right coronary supplies a large portion of the posterior wall of the left ventricle

Sino-atrial nodal branch also comes off right coronary artery.

whereas

left dominant = posterior descending comes off large left circumflex artery, supplying most of the posterior wall of left ventricle.

this time the sino-atrial nodal branch also comes off the left coronary artery

Question 14

what happens in myocardial infarction?

Answer 14

• this is when the coronary artery gets blocked and the perfusion to the myocardium is insufficient to meet the demands of the muscle and therefore there is cell death and irreversible damage to the tissue

Question 15

what does the severity of the disease depend on?

Answer 15

• size and location of the artery
• size of the blockage
• whether there are collateral blood vessels

Question 16

what are the symptoms of the myocardial infarction?

Answer 16

• severe crushing pain
• sweating
• nausea
• pain radiating to the arms

Question 17

label a spinal cord :

Answer 17

Question 18

what does the grey matter contain

what does the white matter contain

Answer 18

grey matter contains the cell bodies

white bodies contains the axons in spinal tracts

Question 19

where do sensory neurones come from?

where do motor neurones come from?

Answer 19

sensory neurons come from the dorsal horn - posterior roots

the motor neurons come from the ventral horn - anterior roots

Question 21

what kind of nerve is the phrenic nerve

where does it arise from ?

Answer 21

the phrenic nerve is a somatic nerve

• it arises from the cervical nerves C3, C4, C5

to combine to make 2 phrenic nerves

Question 22

what is the course of the phrenic nerve?

Answer 22

—Left: over the aortic arch

—Right: lateral to Superior Vena Cava

Question 23

what is the function of the phrenic nerve?

Answer 23

• sensory nerve to the diaphragm, mediastinal pleura, pericardium
• motor neuron to the diaphragm

—(‘C3,4,5 keeps the diaphragm alive’)

Question 25

where might diaphragmic pain be referred to?shoulder tip (C3,4,5 dermatome).

Answer 25

shoulder tip (C3,4,5 dermatome). the same spinal nerves supplying this dermatome

Question 26

what are the intercostal nerves?

Answer 26

Somatic nerves arising from the anterior rami of spinal nerves T1-T11 they form a lateral cutaneous branch - that ends as an anterior cutaneous branch

Question 27

function of intercostal nerves?

Answer 27

- somatic motor function to the muscles of the thoracic wall - •Somatic sensory sensation from overlying skin and parietal pleura

Question 28

where does sympathetic and parasympathetic arise from?

Answer 28

sympathetic: thoracolumbar —nerves T1-L2 parasympathetic: —(CN 3,7,9,10 and S2-s4)

Question 29

what does the White ramus communicans and Grey ramus communicans contain?

Answer 29

White ramus communicans contains myelinated preganglionic sympathetic fibres Grey ramus communicans contains unmyelinated postganglionic sympathetic fibres

Question 30

what is the parasympathetic cardiac innervation?

Answer 30

—Efferents: ￬HR, ￬contraction, constrict coronary arteries

Question 31

what is sympathetic innervation to the cardiac?

Answer 31

—↑HR, ↑contraction

Question 32

what is the cardiac plexus?

Answer 32

- The cardiac plexus is formed of small mixed nerves – containing both sympathetic and parasympathetic nerves

Question 33

how do sympathetic nerves reach the cardiac plexus?

Answer 33

•reach the heart via cardiac branches from the right and left vagal nerves, they synapse at ganglia either at the plexus or in the walls of the atria

Question 34

how do sympathetic nerves reach the cardiac plexus?

Answer 34

- through cardiac nerves from the sympathetic trunk - Preganglionic = fibres from T1-T5 enter and move through the sympathetic trunk to synapse at cervical or upper thoracic ganglia - •The postganglionic fibres then travel to the cardiac plexus from both sides of the spinal cord

Question 35

what does parasympathetic and sympathetic do to the bronchioles?

Answer 35

—Parasympathetic (vagus) nerves – constrict bronchioles —Sympathetic nerves – dilate the bronchioles

Question 36

how does the cardiac conduction system work?

Answer 36

- impulses begin at the SAN - excitation signal spreads across the atria causing atrial contraction - The AVN is then stimulated, which is located near the opening of the coronary sinus - The impulses then travel along the atrioventricular bundle - This splits into the right and left bundle branches which then become continuous with the purkinje fibres - , the electrical impulse serves the papilllary muscle and ventricular musculature - ventricles contract and blood is forced out

Question 37

what is most important for preventing backflow of blood into the right ventricle

Answer 37

A.Pulmonary sinuses