Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Hypertension > normal structure and function > Flashcards

normal structure and function Flashcards

1
Q

name 5 blood pressure determinants in terms of the systems involved and state how they influence BP

A

heart (pumping i.e. CO, which = SV x HR)
blood vessels (tone: TPR. sympathetic nervous system and abnormal sensitivity to catecholamines)
vascular volume (capacitance of the vascular system)
arterial wall distensibility (baroreceptor control)
kidney (regulates blood volume)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fluid flows along vessels only when a ___ ___ exists between the 2 ends of the vessel. The pressure ____ supplies the driving for the flow of fluid.

A

pressure difference

head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is resistance a measure of in terms of fluid moving through vessels?

A

how difficult it is for fluid to flow along a vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why does resistance occur for fluid moving along a vessel?

A

frictional forces between the stationary wall any the moving fluid resist fluid flow through the vessel. (in addition frictional forces also exist within the fluid itself, and are influence by the viscosity of the fluid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

fluid ordinarily flows in an organised streamlined pattern. What is this called?

A

laminar flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

blood flow (Q) within the cardiovascular system is determined by (2)

A
  • a head of pressure developed by the heart

- the resistance to flow encountered within the vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

write the basic flow equation that highlights the relationship between flow, pressure and resistance

A

flow = pressure difference/ resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

using your knowledge of the basic flow equation (flow, pressure, resistance equation) write an equation to calculate total systemic resistance

A

total systemic resistance (PRU) = (aortic pressure - right atrial pressure)/ systemic blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

using your knowledge of the basic flow equation (flow, pressure, resistance equation) write an equation to calculate pulmonary vascular resistance

A

pulmonary vascular pressure = (pulmonary trunk pressure - atrial pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

resistance to flow through a vessel if influenced by which three main factors to do with the vessel?

A

length
inner radius
viscosity of the fluid flowing through the vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why is damage to the arterial tree by hypertension particularly worrying?

A

it damages not only the arterial tree itself, but causes also damage to major organs i.e. brain, eye, heart, blood vessels and kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

state the structural and functional changes that may result from prolonged hypertension

A

larger (elastic) arteries internal elastic lamina thickening, smooth muscle hypertrophy and fibrosis. these changes reduce the lumen, increase shear stress on the intima, increase turbulence, decrease endothelial function and reduce distensibility/ compliance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

as a result of prolonged, uncontrolled hypertension the smaller arteries show ___ ___ which narrows the lumen. This can greatly reduce vessel diameter

A

hyaline sclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what effect do the structural changes found in arteries following hypertension have on peripheral vascular disease?

A

PVR increases. this in turn results in a further increase in blood pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

the rapid development of _____ is an additional complication of hypertension. This is an additional cause of increased ____ ____ resistance.

A

atherosclerosis

peripheral vascular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

does atherosclerosis develop at the same/ an accelerated pace in hypertension?

A

an accelerated pace (particularly in the aorta, cerebral, peripheral and coronary arteries.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

in hypertension, atherosclerosis develops at an accelerated pace - acceleration is more marked in those with associated high risk factors for atheroma, such as (4)

A

diabetes
hypercholesterolaemia
cigarette smoking
impaired glucose tolerance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

name the 2 types of hypertension and state which is the most common

A

essential and secondary (by far the most common is essential: 90-95% of cases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the difference between essential and secondary hypertension?

A

essential is raised BP without obvious case (aka primary or idiopathic) whereas secondary is raised blood pressure when there is an identifiable cause

20
Q

secondary hypertension often develops before the age of ___ years or after ___ years

A

35

55

21
Q

hypertension results in damage to several organs in the body and to the aorta and its main branches. Name some of the adverse effects of hypertension

A

cerebrovascular disease: cerebral haemorrhage
hypertensive retinopathy
carotid artery disease
coronary artery disease: MI, renal artery disease, aortic disease, peripheral arterial occlusive disease

22
Q

name 6 cardiac complications of hypertension

A

left ventricular hypertrophy, MI, myocardial ischaemia, atrial fibrillation, LV failure, congestive cardiac failure

23
Q

what is ischaemia?

A

an inadequate blood supply to an organ or part of the body, especially the heart muscles

24
Q

the myocardium (muscular tissue of the heart) is composed of ___ and non-___ cells

A

myocyte

myocyte

25
Q

cardiac myocytes are enmeshed in a _____ network that acts a supporting framework for the heart.

A

collagen

26
Q

cardiac myocytes are comprised of _____ and ____ myofilaments whose organisation gives rise to the classic ____ appearance of cardiac muscle

A

actin
myosin
striated

27
Q

blood is supplied to individual cardiac myocytes through which vessels

A

capillaries which are in close proximity to them

28
Q

there are 2 prominent organelles within cardiac myocytes - what are these?

A

mitochondria - produce energy

SR - regulates calcium handling in the cell

29
Q

cardiac contraction is initiated when extracellular _____ moves into the cell across the which type of channels?
what does this calcium that enters the cell trigger?
what is this process called

A

calcium
voltage-dependant L-type calcium channels
calcium release from the ryanodine receptor
calcium induced calcium release - CICR

30
Q

how does the calcium released from the SR by CICR induce contraction of the sarcomeres?

A

it binds to the actin thin filaments

31
Q

what happens to the calcium at the end of the contraction sequence?

A

it comes off of the myofilament and is actively transported back into the SR by the calcium pump in its membrane
Calcium is also transported out of the cell to the extracellular space by a membrane bound pump sodium-calcium exchanger

32
Q

cardiac contraction is brought about by interactions between the ____ thin filament and the ____ cross-bridges that project from the thick filament shown in red

A

actin

myosin

33
Q

what prevents actin interacting with the myosin cross-bridges when the cardiac muscle is relaxed?

A

the conformation of troponin and tropomyosin

–> as a result actin is unable to interact with the myosin cross-bridges containing bound ATP

34
Q

how can the actin interact with the myosin cross-bridges in activated cardiac muscle then?

A

calcium binds to the troponin which then shifts troponin complexes and tropomyosin to an active conformation and enables actin to interact with the myosin cross-bridges

35
Q

what provides the requisite energy for the myosin cross-bridges to interact with the actin thin filament?

A

myosin ATPase on the myosin heads hydrolyses the bound ATP on myosin

36
Q

what does the myosin heads do to the actin thin filaments when they do interact?

A

pulls them towards the centre of the sarcomere in a ratchet like fashion (the whole process is known as excitation-contraction coupling)

37
Q

the process of excitation-contraction coupling becomes disregulated in cardiac ______ and cardiac ______

A

hypertrophy

failure

38
Q

following sustained hypertension the heart develops concentric ______, which is characterised by thickening of the ___ ___ and the ____ ____ of the left ventricle

A

hypertrophy
IV septum
free wall

39
Q

true or false: ventricular hypertrophy in response to sustained hypertension is immediately a problem for the heart as soon as it develops

A

false - it is initially adaptive, allowing the heart to maintain normal pump performance with the increased afterload (resistance against which heart has to pump) imposed by an elevated BP

40
Q

name a maladaptive change that occurs in the extracellular matrix as a result of ventricular hypertrophy and state what effect this has on normal heart function

A

increase in the fibrillar collagen network that surrounds the individual cardiac myocytes (prevents heart from contracting and relaxing normally)

41
Q

name a maladaptive change that occurs within the cardiac myocytes as a result of ventricular hypertrophy and state what effect this has on normal heart function

A

decrease in the amount of calcium that’s released from the SR - causing a decrease in the amount of sarcomere shortening causing myocyte dysfunction

42
Q

one of the best recognised of sustained hypertension is the development of dilated ________. What is this characterised by?

A

cardiomyopathy

progressive dilation of the left ventricle and decreased systolic performance of the left ventricle

43
Q

one of the hallmarks of dilated cardiomyopathy is the progressive thinning of the ____ ____ wall as well as an increase in overall ____ ____ cavity dimension

A

left ventricular

left ventricular

44
Q

how does dilated cardiomyopathy affect the myofilaments? what is this accompanied by? what are both these abnormalities throught to contribute towards?

A

leads to progressive dissarray of the myofilaments accompanied by excessive myocardial fibrosis
to the depressed systolic performance of the left ventricle

45
Q

what is myopathy

A

a disease of muscle tissue

46
Q

how does dilated cardiomyopathy affect the contraction-excitation coupling in the failing myocyte?

A

calcium influx through the L-type calcium channel results in decreased release of calcium from the SR. The decrease in calcium available to activate the cross-bridges leads to decreased sarcomere shortening and to myocyte dysfunction. In addition there is also decreased function of the calcium pump of the SR that removes calcium from the cytosol back to the SR (contributing to the decrease in calcium that’s available to activate the cross-bridges as the myocyte contracts)

47
Q

there are abnormalities of excitation-contraction coupling in the hypertrophied heart - what is the net result of these in terms of sarcomere shortening?
These abnormalities are thought to contribute to the development of ____ ____ systolic dysfunction in the failing heart

A

decreased speed and extent

left ventricular

Hypertension (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions