L5&6 - Cardiovascular

Question 1

what does the involuntary nervous system consist of?

Answer 1

2 neurone system
neurotransmitters ACh snd noradrenaline
2 anatomical divisions

Question 2

what is the two neurone system?

Answer 2

preganglionic neurones which synapse on postganglionic neurones

Question 3

what are the 2 anatomical divisions of the involuntary nervous system?

Answer 3

sympathetic and parasympathetic

Question 4

what division of the sympathetic nervous system innervates almost every organ?

Answer 4

thoraco-lumbar division

Question 5

what division does the parasympathetic nervous system consist of?

Answer 5

cranio-sacral division

Question 6

what is the function of the sympathetic nervous system?

Answer 6

important for reactions - fight or flight

Question 7

what is the function of the parasympathetic nervous system?

Answer 7

maintaining and restoring body energy - rest and digest

Question 8

what is the adrenal medulla innervated by?

Answer 8

preganglionic sympathetic nerves

Question 9

what are adrenal medulla cells?

Answer 9

modified ganglion cells

Question 10

what does the adrenal medulla do?

Answer 10

• release adrenaline into bloodstream (80% adrenaline 20% noradrenaline)
• regulates primary metabolic events

Question 11

what does the hypothalamus regulate?

Answer 11

• reproduction
• thirst/hunger
• reaction to stress
• emotion control
• sleep cycle/circadian rhythm

Question 12

what are the layers of the heart?

Answer 12

• pericardium
• epicardium
• myocardium
• endocardium

Question 13

what phase comes after depolarization in cardiac action potential?

Answer 13

plateau phase due to movement of extracellular calcium into the muscles

Question 14

what phase of the action potential is longer to ensure tetany does not occur?

Answer 14

refractory period - relaxation of the muscle has started by the time this period ends

Question 15

what are the 2 sources of calcium in the cardiac muscle?

Answer 15

sarcoplasmic reticulum and extracellular

Question 16

what is auto-rhythmicity?

Answer 16

the heart can spontaneously generate its own action potentials without external stimulation from nerves - thanks to the conduction system

Question 17

what is the conduction system and where does it originate?

Answer 17

small network of contractile cells in the right atrium as an area called the sino-atrial node

Question 18

what are the 5 areas of generation through the conduction system?

Answer 18

1. sino-atrial node
2. atrioventricular node
3. atrioventricular bundle (bundle of His)
4. right and left bundle branches
5. purkinje fibres

Question 19

explain how the SA node is innervated by the parasympathetic nervous system

Answer 19

increased parasympathetic nerve (vagus nerve) activity decreases heart rate

Question 20

explain how the SA node is innervated by the sympathetic nervous system

Answer 20

increased sympathetic nerve activity increases heart rate

Question 21

explain how the myocardium is innervated by the sympathetic nervous system

Answer 21

increased sympathetic nerve activity increases cardiac contractility while decreased sympathetic activity decreases contractility

Question 22

what is diastole?

Answer 22

relaxation period

Question 23

what is systole?

Answer 23

contraction

Question 24

explain the lead up to the 1st heart sound

Answer 24

• ventricular diastole and the pressure within them falls
• AV valves open and blood flows from both atria into the ventricles
• as the ventricles fill up, the pressure rises and the AV valves snap shut

Question 25

explain the lead up to the 2nd heart sound

Answer 25

• ventricular systole = when the pressure rises higher than pulmonary and aortic pressure, the semi-lunar valves open silently and blood is ejected into the 2 arteries
• the semi-lunar valves snap shut