cardiovascular disease Flashcards

1
Q

What are the cardiovascular diseases?

A

pericarditis
valve defects (stenosis and regurgitation)
-defects in the specialised excitatory and conductive system
-hypertension
-assorted congenital heart defects

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2
Q

What is the assorted congential heart defects?

A
  • septal defects (hole in heart)- oxygenated and deoxygenated blood mix
  • development of single ventricle
  • coarctation of aorta (narrowing)- if blood vessel is too big, it will press on blood vessels underneath- causing narrowing
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3
Q

What is the structure of blood vessels?

A

Veins- bring blood to the heart
Arteries- take blood from the heart
Capillaries- gas and nutrient exchange

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4
Q

What is the structure of the arteries ?

A
Tunica Interna
Endothelial cells
Internal elastic lamina
Tunica Media
External elastic lamina
Tunica Externa
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5
Q

What is the tunica interna made of in the arteries?

Why?

A

Simple smooth endothelium - it provides a frictionless surface for the movement of blood - so you dont get blood clotting

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6
Q

What are the endothelial cells?

A
  • are continuous with heart and blood vessel

- have smooth frictionless lining for both blood vessels and heart

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7
Q

Location of the endothelial cells?

A

sits on the basement membrane

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8
Q

What is the internal elastic lamina?

A

separates the tunica interna from the tunica media

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9
Q

What is the inner layer of a blood vessel?

A

simple endothelium, sitting on a basement membrane, surrounded by internal elastic lamina

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10
Q

What is the bulk of the artery?

A

Tunica Media

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11
Q

What is tunica media composed of?

A

made of smooth muscle

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12
Q

What are arteries?

A

Mostly muscular
up to 40 layers of smooth muscle
some elastic and collagenous connective tissue.

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13
Q

Why are there muscles in blood vessels?

A

-To make blood vessels wide and narrow- to regulate B.P
- Close blood vessel down, if you are cut/injured
-Re-direct blood
But NOT to squeeze the blood along

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14
Q

What else does the tunica media have?

A

Nerve supply to artery- sympatheic ANS innervates smooth muscle of most arteries

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15
Q

What are in the larger vessels of the arteries?

A

Blood vessels in blood vessels -have vessels in their walls called Vasa Vasorum

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16
Q

What is the outer layer of the artery?

A

Tunica externa

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17
Q

What is the tunica externa made of?

A
  • Several layers of longitudinal ,collagenous connective tissue- tough outer coat
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18
Q

Why are not all arteries the same?

A

They vary in thickness and composition of the various layers

  • Closer to heart- arteries are larger
  • Further to heart- arteries are smaller
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19
Q

What are the arteries closest to the heart known as?

A

Elastic/conducting arteries (with the same 3 layers)

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20
Q

What is different about these elastic arteries?

A
  • They dont have that much smooth muscle in the tunica media

- Mainly have elastic tissue

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21
Q

What does the elastic property do in the arteries?

A

When the heart contract- blood is pushed into the arteries- it gets bigger and dilates

  • When the heart relaxes- arteries collapse
  • they even out the pressure of the heart contracting and relaxing
  • The recoiling - helps push blood along
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22
Q

What are the muscular arteries?

A
  • Like generalised artery - tunica media mainly consists of smooth muscle
  • serve to distrubute blood to the different organs of the body
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23
Q

What are arterioles?

A
  • They consist of endothelium with a bit of smooth muscle cells around them
  • Small diameter = less than 0.5mm
  • They regulate B.P
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24
Q

What are capillaries?

A
  • exchange of nutrients and respiratory gases
  • Small diameter = 7-9 um
    length= 0.25-1mm
    Distrubution depends on tissue- e.g. skeletal muscle have lots of capillaries, cornea have no capillaries
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25
Q

what are the 2 types of capillaries?

A

Continuous cappilary

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26
Q

What is the structure of the continuous capillary?

A

Adjacent endothelial cells (which sit on the basement membrane) are joined by tight junctions.
The exchange of nutrients go through the cells called Pinocytic vesicles

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27
Q

What is the structure of the fenestrated capillary?

A

60-100nm
Lots of pores covered by a thin membrane over it.
It is for the rapid exchange of nutrients
e.g eye= behind retina, within the ciliary body you have a lot of fenestrated capillaries

28
Q

how do you control capillary blood flow?

A

Rings of smooth muscle= Pre- capillary sphincter

  • When they contract, they stop blood from going to capillary bed
  • the blood will go straight from the arteriole to the venule
  • Deoxygenated blood ends up in the venule
29
Q

What is the structure of the vein/venule?

A

Diameter= 0.2-1mm
Thin wall- vein- see blood through them
venule has thinner walls but slightly larger lumen than arterioles
-Tunica media is reduced/thinner= much less smooth muscle
-Tunica externa= thicker
-Appear darker, see blood through them

30
Q

How do the blood vessels appear in the fundus of the retina?

A

vein= darker- due to their thinner walls
artery- lighter
- Also arteries cross over veins and can squash veins
-The arteries are closer to the vitreous

31
Q

How does blood pressure vary between the veins and arteries?

A

Veins have low B.P
Arteries have a higher pressure than in veins.
Veins are further away from the heart therefore means less B.P variation

32
Q

What are the properties of the veins in the leg?

A

Veins have valves in them

  • pushes blood up the veins when heart contracts
  • when heart relaxes, blood flows down veins and valves shut
  • Skeletal muscle of the leg (muscle around blood vessel)- contract and help squeeze blood up the veins
33
Q

What are varicose veins?

A

When valves break down in veins.

Valves seize to function properly and blood accumulate

34
Q

What causes varicose veins?

A
  • downward pressure such as

pregnancy, obesity, standing up

35
Q

What is a disease of blood vessel?

A

Artherosclerosis (atheroma)

36
Q

What is artherosclerosis/atheroma?

A
  • deposition of fibrous growths (plaques) within the tunica interna of arteries
  • causes heart attack,stroke
  • depositing on blood vessels (mainly arteries) of dense fibrous PLAQUES
37
Q

How does atheroma form?

A
  1. Inside of blood vessel gets damaged- endothelium damaged due to high B.P, hypertension, smoking, virus
    2.Damaged endothelial cells release chemotactic factors (|chemical signals)
  2. Lead to the accumulation of LDL which oxidise
  3. LDL deliver cholesterol to tissues
  4. Macrophages ingulf oxidised lipotproteins and cholesterol and form cells called FOAM CELLS.
    They cause the formation of a fatty ‘yellow streak’ in the vessels tunica interna.
  5. Smooth muscle from tunica media migrates to tunica interna to prevent more damage by replicating and producing collagenous connective tissue
    7.Calcium deposits from blood plasma are formed and infiltration of WBC
  6. Lump in tunica interna and tunica media starved of oxygen and scar tissue forms
  7. Blood vessel lumen decreased
38
Q

Why does atheroma form? (aetiology)

A
male and over 40
overweight
no excerise
diet
stress
alcohol 
smoking
diabetes
oral contraceptives
genetics
39
Q

what are the consequences of atheroma ?

A
  1. smaller blood vessels may become blocked
  2. plaques may become the site of thrombosis
  3. a piece of plaque become detached and form an embolism
  4. a plaque can be the site of aneurysm
40
Q

what happens when blood vessels become blocked?

A

arteries become narrowed and blood flow decreases in atherosclerosis

41
Q

why is it unusual to get blood clot in vessels?

A

.smooth endothelium giving you smooth frictional flow of blood
.blood clot will only occur if flow of blood is turbulent

42
Q

what is thrombosis ?

A

when a blood clot forms in the vein , this causes deep vein thrombosis pulmonary embolism

43
Q

what is embolism?

A

blocked artery due to blood clot

44
Q

what is aneurysm?

A

weakening of artery wall creating bulge artery
aneurysms can burst leading to haemorrhage
they are also site of thrombosis
to fix aneurysm they can be clipped or bound

45
Q

what is deep vein thrombosis caused by ?

A

DVT is caused by
. endothelial damage
. hypercoagulability - blood vessel chemistry can change
. venous stasis - slow blood flow in vein usually of legs

46
Q

what are the symptoms of DVT ?

A

. pain
. swelling
. redness
. warmness

47
Q

what is venous thromboembolism ?

A

it is a consequence of thrombosis where part of blood clot becomes detached and travels to the lungs

48
Q

summarise cardiovascular disease ?

A

atheroma is growth of plaques in the walls pf artery this leads to
. aneurysm
. thrombosis
. embolism
leading to blockage
leading to ischaemia - not enough oxygen in tissue
leading to infraction - tissue death due to lack of blood supply

49
Q

what does the size of infracts depend on ?

A

. extent of collateral circulation
. duration of ischaemia
. susceptibility of tissue to ischaemia

50
Q

where do infracts occur ?

A

infracts can occur everywhere in the body
. spleen
. kidney
. liver

51
Q

what does the seriousness of an infract depend on?

A

depends on the tissue

52
Q

what is the most sensitive tissue to lack of oxygen ?

A

. neurons in the CNS
. CNS tissue need continuous supply of oxygen
. CNS tissue does not regenerate

53
Q

what is loss of CNS tissue known as ?

A

death of neurons in CNS due to lack of oxygen is known is stroke

54
Q

what are the two types of CNS strokes ?

A

. haemorrhagic - aneurysm bleed in brain

. ischaemic - blood vessel gets blocked

55
Q

what is an example of organ that can have multiple infracts ?

A

. kidneys have a large functional reserve and extensive and multiple infracts are needed to impair function noticeably

56
Q

what is myocardial infraction serious?

A
  1. the heart needs to keep beating uninterrupted

2. cardiac muscle is amitotic ( stays dead )

57
Q

what is the function of the right and left coronary arteries ?

A

they supply the heart muscle itself with blood

they are susceptible to plaque formation

58
Q

what is coronary arterial disease / ischaemic heart disease ?

A

. the narrowing of the coronary arteries by atheroma results in the heart muscle receiving insufficient oxygen leading to impaired contraction

59
Q

what is the consequence of atheroma in coronary arteries ?

A

. angina pectoris

. myocardial infraction ( heart attack )

60
Q

what is angina pectoris ?

A

consequence of atheroma in coronary arteries
caused by short term inadequacy of the blood supply to the heart during times of increased demand
e.g. stress

61
Q

what is myocardial infraction ( heart attack )

A

serious consequence of atheroma in coronary arteries
blood supply is disrupted for longer
e.g if thrombosis forms on an atheromatous plaque in the coronary arteries , heart muscle may die

62
Q

what does the severity of infarcted myocardial tissue depend on ?

A

depend on size and location

63
Q

what are causes of death following myocardial infarction ?

A
  1. insufficient cardiac output - not enough blood pushed
  2. rupture of infracted area some time after attack
  3. ventricular fibrillation - heart quivers instead of pumping due to disorganized electrical activity in the ventricles.
  4. pulmonary oedema- left ventricle not pushing enough blood
64
Q

how to prevent myocardial infraction ?

A
  1. clot bursting drugs
  2. drugs to prevent clots forming ( aspirin )
  3. coronary by-pass surgery
  4. angioplasty/stent
  5. injection of stem cells into infracted area to produce new cardiac muscle
65
Q

what are examples of drugs to lower blood pressure and lessen risk of CVA ?

A
  1. aspirin - inhibits production of thromboxane
  2. ACE inhibitor - prevents vasoconstriction via renin pathway
  3. statins - lower cholesterol
  4. arterial calcium channel blocker - prevents vasoconstriction