Cardiovascular regulation

Question 1

What is cardiodynamics?

Answer 1

movements and forces generated during cardiac contraction

Question 2

What is EDV?

Answer 2

End diastolic volume - amount of blood in each ventricle at the end of ventricular distole

Question 3

What is ESV?

Answer 3

End systolic volume - amount of blood remaining in each ventricle at end of ventricular systole

Question 4

What is SV?

Answer 4

Stroke volume - amount of blood pump out of each ventricle during a single heart beat

Question 5

What is Ejaction fraction?

Answer 5

Percentage of EDV represented by SV

Question 6

What is preload of HR?

Answer 6

degree of stretching in ventricle muscles during diastole, proportional to EDV greater preload larger EDV

Question 7

What is afterload of HR?

Answer 7

Amount of tension that the contracting ventricle must produce to force open SV and eject blood

Question 8

What factors affect stroke volume?

Answer 8

Autonomic innervation
hormones
EDV
ESV

Question 9

How does preload influence EDV?

Answer 9

Increase energy of myocyte contraction
degree of stretch on myocyte
venous return and filling time infleunce

Question 10

What factors effect ESV?

Answer 10

Preload (force produced for contraction)
Contractibility of ventricle
Afterload

Question 11

What is contractility?

Answer 11

Amount of force produced during contraction at preload.
increase contractility = positive inotropic agents
Decrease contractility - negative inotropic agents

Question 12

What positive inotropic agents are there?

Answer 12

Neurotransmitters

b-adrenergic agonists

Question 13

What negative inotropic agents are there?

Answer 13

ACh
Ca channel blockers (verapamil)
muscarinic agonist
anoxia
acidosis

Question 14

What is afterload?

Answer 14

Tenstion the contracting ventricle produce to eject blood
pressures are 80mm and 20mm for SV
if afterload increases preload is constant Stroke volume decrease more blood remain
Afterload increase as narrow arteries and hypertension

Question 15

What does the cardiac centre in medulla?

Answer 15

Cardioaccelaratory centre increase HR via sympathetic
Cardioinhibitory slows heart
both cardiac centres monitor changes in BP o2 and PH

Question 16

What is the atrial reflex?

Answer 16

adjustments in HR in response to increase in venous return

Question 17

Homeostatis mechanisms in CV centre ensure efficient blood flow for ?

Answer 17

appropiate Tissue perfusion

Question 18

Tissue perfusion influenced by?

Answer 18

CO
BP
PR

Question 19

Tissue perfusion mechanisms are?

Answer 19

Autoregulation
Neural mechanisms
Endocrine response

Question 20

What does localised vasoconstriction and vasodilation of blood flow where?

Answer 20

Precapillary spincter muscles

Question 21

What are local vasodilators?

Answer 21

low O2
Lactic acid
NO
low PH
Histamine agents
Increase temp

Question 22

What are local vasoconstrictors?

Answer 22

Thromboxanes (released by platelet)

Endothelins (damaged endothelial cells)

Question 23

When are endocrine factors activated?

Answer 23

autoregulation of BF fails to normalise conditions

Question 24

What is the Vasomotive centre?

Answer 24

2 populations of cells in medulla associate lots with vasoconstriction and small with vasodilation

Question 25

What does control of vasoconstriction include?

Answer 25

neurons innervate peripheral blood vessles in tissues are adrenergic Release NA stimulates a1 adrenoreceptors in PM of SMC

Question 26

What controls vasodilation?

Answer 26

neurons in skeletal muscle in brain relax smc in arterioles Mainly cholinergic ACH triggers NO Nitroxidergic release NO

Question 27

Where are baroreceptors located?

Answer 27

In carotid sinus, aortic sinus and wall of right atrium

Question 28

Where are aortic and carotid baroreceptors?

Answer 28

Aortic in ascending aorta monitor stretch and BF | Carotid monitor BP in carotid arteries blood supply

Question 29

Increase in BP detected by baroreceptors regulate what?

Answer 29

Inhibition of cardio-accelaratory centre | Inhibition of vasomotor cells with vasoconstriction

Question 30

What is atrial reflex/bainbridge?

Answer 30

regulatory feedback to increase HR

Question 31

What are chemoreceptors sensitive to?

Answer 31

Changes in blood oxygen, CO2 and PH

Question 32

What long term hormonal mechanisms to control BP?

Answer 32

ADH Angiotensin II EPO ANP/BNP

Question 33

What does ADH do?

Answer 33

posterior lobe of pituitary increase peripheral constriction due to low blood volume

Question 34

what converts angiotension I to angiotensin II?

Answer 34

By ACE

Question 35

What are 4 important functions of angiotensin II?

Answer 35

Stimulates secretion of adrenal aldosterone Stimulates secretion of ADH Stimulates thirst Stimulates CO and vasoconstriction

Question 36

What does EPO do?

Answer 36

Causes vasoconstriction in Blood vessels, produces RBC improve O2

Question 37

What does natriuetic peptides do?

Answer 37

Released from atrial myocytes for excessive strethcing act on kidney increase urine production