cardiology

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  • Created by: maddie289
  • Created on: 28-01-21 13:17
explain the pacemaker function within the heart
1. the SAN is the primary pacemaker
2. is affected by calcium and sodium ions (known as the calcium clock)
3. allows the cardiac cells to return to a stable state before being depolarised again (hyperpolarisation)
1 of 30
what's the cardiac output equation?
cardiac output = heart rate X stroke volume
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explain how extrinsic control of the heart works
1. stimulation is via the sympathetic cardioacceleratory centre - the caudal ventrolateral medulla and the rostroventrolateral medulla
2. inhibited by the parasympathetic cardioinhibitory centre -dorsal vagal nucleus and the nucleus ambiguous
3 of 30
how is the heart controlled intrinsically?
the brainbridge reflex - increased venous return stimulates the SAN which increases heart rate
(due to increased central venous pressure)
4 of 30
explain Starling's Law of the Heart
1. energy of contraction is proportional to the muscle fibre length at rest
2. stretch increases with calcium sensitivity
5 of 30
what is the equation used to explain blood flow?
flow = proportional to the change in pressure / resistance
6 of 30
give examples of factors that decrease blood flow
1. smaller radius
2. longer vessel
3. more viscous fluid
7 of 30
what are the different blood flow patterns?
1. laminar flow - streamline and how blood should flow
2. turbulent flow - high pressure changes and cross currents - not efficient
3. bolus flow/single file - low friction, RBCs bend to fit through
8 of 30
describe Poiseuille's Law
1. to describe flow
2. directly proportional to the pressure drop
3. inversely proportional to the vessel length
4. inversely proportional to the fluid viscosity
5. Flow = change in pressure X pi radius4/ 8 X length X viscosity
9 of 30
explain Darcy's law
1. to explain resistance
2. the difference in mean pressure needed to drive one unit of flow
10 of 30
how do you determine blood pressure?
1. blood pressure = cardiac output X total peripheral pressure

2. cardiac output = mean aortic pressure - central venous pressure / total peripheral pressure
11 of 30
how do you work out pulse pressure?
pulse pressure = systolic pressure - diastolic pressure
12 of 30
how do you work out mean arterial pressure?
mean arterial pressure = diastolic pressure + 1/3 pulse pressure
13 of 30
what is a dichrotic notch?
1. where the aortic valve shuts leading to 2
waves in the brachial artery
2. can be seen on blood pressure graphs
14 of 30
give examples of factors which affect blood pressure
1. age
2. activity levels
3. sleep
4. breathing
5. gravity
15 of 30
explain the short term control of blood pressure
1. via baroreceptors
2. regulates the blood vessel diameter and
cardiac output
16 of 30
explain long term control of blood pressure
1. via the kidneys
2. they alter blood volume
3. an increase in blood volume causes an
increase in blood pressure
4. renin-angiotensin-aldosterone system
17 of 30
what are the neural vasoactive agents?
1 .sympathetic nerves - vasoconstrictors
2. nitric oxide - vasodilators
18 of 30
what are the hormonal vasoactive agents?
1. angiotensin II - vasoconstrictor
2. adrenaline - vasodilator
19 of 30
what is the ideal blood pressure?
anywhere from 90/60 to 120/80
20 of 30
high blood pressure is what result?
anywhere from 140/90 and above
21 of 30
name the causes of essential hypertension
1. high salt and alcohol consumption
2. lack of exercise
3. obesity
4. genetic factors
22 of 30
what are some consequences of arterial damage?
1. stroke (ischaemic or haemorrhagic)
2. aneurysms
3. myocardial infarction
4. retinopathy
4. nephrosclerosis and renal failure
23 of 30
explain heart failure
1. when the heart is incapable of continuing adequate cardiac output
2. metabolic requirements cannot be accommodated
3. symptoms include: breathing difficulty,
fatigue, coughing
24 of 30
explain central venous pressure
the volume of blood in circulation/ distribution
of blood between central and peripheral veins
25 of 30
what are the different conditions associated
with shock?
1. hypovolemic shock -haemorrhage,
surgery, trauma
2. low resistance - sepsis, anaphylaxis
3. cardiogenic - heart failure
4. obstructive - pulmonary embolism, pneumothorax
26 of 30
explain the change in blood flow position during exercise
1. at rest the majority of blood flow is towards/ in the abdominal organs and kidneys
2. during exercise the blood flow is shunted towards the skeletal muscles
3. skeletal muscles require more blood flow in order to supply cells with needed
oxygen and e
27 of 30
describe the dive response
1. the body is plunged into deep water
2. physiological changes include apnoea, bradycardia, peripheral vasoconstriction
4. conserves body temperature and energy
28 of 30
describe the cold water shock
1. when the body is plunged into cold water a different response is seen compared to the dive response
2. tachycardia, a respiratory gasp, uncontrolled hyperventilation
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what is emersion diuresis?
1. a physiological response to the body/body
part being immersed in water
2. there is an upward shift of fluid
3. blood volume increases causing bigger
cardiac stretches
4. produces natriuretic peptides
5. results in natriuresis and diuresis
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Other cards in this set

Card 2

Front

what's the cardiac output equation?

Back

cardiac output = heart rate X stroke volume

Card 3

Front

explain how extrinsic control of the heart works

Back

Preview of the front of card 3

Card 4

Front

how is the heart controlled intrinsically?

Back

Preview of the front of card 4

Card 5

Front

explain Starling's Law of the Heart

Back

Preview of the front of card 5
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