Brainscape's Knowledge GenomeTM

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


See full index

2. Foundations of Medicine PoD > Circulatory Pathology > Flashcards

Circulatory Pathology Flashcards

1
Q

lumen

A

The cavity or channel within a tube or tubular organ such as a blood vessel or the intestine

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

Blood vessel/arteriole: what is it and what cells/components line it

A

smallest artery before capillary

Endothelial cells line lumen (stretchy) making a basal lamina (basal membrane) to sit on. Smooth muscle cells found around basal lamina, with interstitial collagen fibres around them

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

elastic recoil

A

smooth muscle cells in blood vessels: work in stretching and the recoil

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

What does the blood vessel lumen contain

A
  • RBC’s
  • WBC’s
  • platelets (white in colour and small)
  • plasma (water and numerous proteins/other molecues)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Composition of plasma

A

non cellular (e.g. proteins like albium and immunoglobulins and other molecules)

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

What are platelets not normally exposed to

A

interstitial collagen fibres around vessel (normally stay in blood vessel and only touch endothelial cells)

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

components of blood other than plasma

3

A

RBS, WBC and platelets

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

What key element does plasma contain

A

clotting factors

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

what is serum

A

plasma without clotting factors

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

Explain clotting factors (origin and breifly summarise their action/pathway)

A
  • Many are mainly produced in the liver (but also by endothelial cells)
  • They are an amplification system, resulting in thrombin production
  • Thrombin, in turn converts soluble fibrinogen into insoluble fibrin
  • Fibrin forms a mesh of strands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What can the clotting cascade be known as

A

an amplification system

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

Since the clotting cascade is an amplification system what are many more molecules produced

A

fibrin compared to say, TF (tissue factor)

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

Clotting cascade pathway

A

see sheet

seriously, actually learn this one

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

clotting cascade function

A

detects initial damage, binds up bacteria & injured cells to keep them from causing more harm in areas

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

Initial drama to cause clotting cascade

A

Obvious one is trauma
Leads to:
1. exposure of interstitial collagens (collagens in CT between structures)
2. Eposure of a molecule called tissue factor (TF)

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

process leading to clotting cascade

A

trauma= interstitial collagens exposed and TF exposed

  1. trauma results in defects in vessels
  2. blood leaks out and serum comes into contact with interstitial collagen fibres
  3. plasma clotting factors can now be activated as they contact interstitial collagens
  4. TF released from smooth muscle cells
  5. TF can now bind a particular clotting factor and initiate the clotting cascade
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how does a clotting factor become activated

A

When your body detects a bleed, the clotting factors are switched on in a particular order, one after the other. Each factor activates the next until they form a clot

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

clotting factors as serine proteases

A

Many clotting factors are serine proteases - that is they have a serine amino acid in them and they cleave other clotting factors to form the active molecule

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

what do clotting cascades lead to the production of and what does this do

A
  • production of thrombin from prothrombin
  • thrombin converts soluble fibrinogen to insoluble fibrin
  • endpoint of clotting cascade production of insoluble fibrin strands that form meshwork
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

fibrinogen vs fibrin

A

see sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

platelets - origin

A
  • Produced in bone marrow
  • From cell called a megakaryocyte
  • Megakaryocyte = Large cell with many nuclei
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

megakaryocyte in bone marrow- formation of platelets

A

undergoes nuclear division but not cell division so get huge cell with many nuclei, platelets bud off as fragments from cytoplasmic extensions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how do platelets work

A
  • trauma to vessel-> exposure of platelets to interstitial collagen
  • platelets adhere together try to form bridge to close gap
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

coagulation - meaning and types

A

Solidification of blood

  1. Thrombus formation
  2. Clot formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

thrombus formation/facts

A
  • occurs in flowing blood
  • pure thrombus= pale cream coloured
  • thrombus consists of platelets and a mesh like network of fibrin strands
    -thrombosis (process of thrombus formation) occurs in flowing blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

why does a thrombus of platelets and fibrin occur in flowing blood

A

platelets have molecules on their surfaces which allow adherence to interstitial collagen, even when blood is flowing past them - the clotting cascade deposits Factor VIII which enhances this further

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

explain clot formation

A
  • blood leaks out of a vessel and becomes stationary/stagnant
  • within the stagnant blood- clotting cascade activated
  • clot consists of a network of fibrin strands and red blood cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

colour of clot

A

red (due to prescence of RBC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

haemostasis

A

stopping bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Give an example of haemostasis in normal skin with a wound

(stopping bleeding)

A
  1. vessel surrounded by collagen
  2. blood flows through vessel in skin
  3. trauma to skin disrupts one side of vessel
  4. blood, including RBCs leaks out
  5. clotting system activated by collagen and stagnant blood, forming clot
  6. may not work perfectly and wound may continue to bleed
  7. vessel vasoconstricts to decrease blood loss
  8. platelet and fibrin thrombus forms to bridge the gap between the ends of the vessel adjacent to flowing blood
  9. skin now stops bleeding - haemostasis has been achieved
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

3 things that can happen in wound due to trauma to stop bleeding

A
  1. Vasoconstriction - helps dec bleeding
  2. Clot formation occurs in space around vessel and may fill void of wounded tissue
  3. Thrombus forms in flowing blood and stops bleeding from gaps in vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

granulation tissue

A

-new vessels that grow into area of wound
-the capillaries that grow in (granulation tissue) can oxygenate the area of the wound and keep it alive
-scarring etc. then happen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

how is the thrombus removed

A

Plasminogen converts to plasmin, and plasmin cuts up fibrin into smaller fragments, as a way of removing fibrin (in both clots and thrombi). In a thrombus this is sometimes called thrombolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

thrombolysis

A

lysis (splitting) and removal of the thrombus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how is excess thrombus or clot removed (in blood)

A

In blood there is a fibrinolytic system which removes fibrin and stops thrombi from propagating,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what do fibrinolytic system depend on

A
  • Plasminogen being converted to plasmin
  • Plasmin cuts up fibrin into fibrin degradation products
37
Q

what cuts up fibrin in a thrombus

A

plasmin

38
Q

What 2 thing must be in balance to stop bleeding but also ensure a capillary/vessel does not get blocked

A

fibrinolytic and clotting systems

39
Q

What are thrombosis and clotting normal in

A
  • wound healing
  • stopping bleeding during menstruation
40
Q

3 main causes/predisposing situations that may result in thrombosis

LEARN ME

A

1.Changes in the intimal surface of a vessel (e.g. trauma)
2.Changes in the pattern of blood flow
3.Changes in the blood constituents

known as Virchow’s triad

41
Q

summarise thrombi in 1 sentence

A

platelets admixed with fibrin and form in flowing blood

42
Q

summarise clot in 1 sentence

A

fibrin admixed with RBC and forms in stagnent blood

43
Q

3 important factors in wound healing

A

thrombosis, clotting, vascoconstriction

44
Q

main site of production of clotting factors

A

liver

45
Q

physiological thrombosis

A

normal after cut or other injury

46
Q

pathological thrombosis

A

occurs in absence of a cut or traumatic injury

47
Q

Virchow’s triad

A
  1. changes in the intimal surface of a vessel
  2. changes in the pattern of blood flow
  3. changes in the blood constituents
48
Q

example of virchow’s triad- coronary artery thrombosis

A
  • coronary arteries supply heart muscle
  • smoking increases ‘stickiness’ of platelets
  • makes it more likely that a thrombosis occurs
  • alteration in properties of blood= change in blood constituents which is part of virchow’s triad
49
Q

what can predispose to atheroma in the coronary arteries

A

cigarette smoking (/high lipid in blood etc.)

50
Q

atheroma

A
  • disease of coronary arteries which results in the build up of lipid under the intimal surface
  • lipid can result in abnormal blood flow (can get both slow and turbulent flow)
  • Slowed blood flow predisposes to fibrin and platelet clumping
  • Lipid (and collagen) can also rupture through the intimal surface
  • platelets and fibrin now exposed to an abnormal substance (lipid and collagen) and turbulent flow and are deposited as a thrombus
  • thrombus blocks the lumen of the coronary artery
  • Clot can now form in the stagnant blood behind the thrombus

(change in pattern of flow = virchow’s triad)

51
Q

what does atheroma result in

A

(big) blood clot behind (small) thrombus

52
Q

briefly describe the more complex layers of atheroma/clot in blood vessels

A

1st - thrombus (platelets and fibrin)
2nd - RBC trapped in fibrin meshwork
3rd - complex structure protrudes even further into lumen causing more turbulence/slowing so get 3rd layer of thrombus
And so on…

53
Q

what do multiple layers of thrombus and clot lead to

A

lines of Zahn

(pale layers of thrombus alternating with red layers of clot)

54
Q

Do we need all 3 of Virchow’s triad to get a thrombus/clot formation

A

No just 1 badly

55
Q

Where can thrombus/clot formation happen

A

arteries, veins, capillaries, pre-capillaries

56
Q

What could all 3 situations occuring in Virchow’s triad lead to

A

coronary artery thrombosis

57
Q

what happens when a thrombus blocks an artery

A
  • Complete obstruction leads to no flow beyond blockage
  • Partial obstruction leads to decreased flow beyond blockage
  • The tissue supplied by this artery receives less blood flow
58
Q

ischaemia

A

poor blood flow leading to decreased oxygenation of tissue - hypoxia

59
Q

ischaemia

A
  • An inadequate supply of blood to a part of the body caused by blockage of an artery
  • If it is severe enough ischaemia leads to decreased oxygenation of tissues (=hypoxia).
  • The tissue is said to be ‘ischaemic’- localised area of tissue dies
60
Q

How does ischaemic heart tissue feel

A

painful

61
Q

what could cause a localised area of tissue to die

A

severe or total blockage of blood flow meaning the lack of blood flow (ischaemia) leads to severe lack of oxygen (hypoxia) and causes a localised area of tissue to die

62
Q

infarct

A

tissue death or necrosis due to inadequate blood supply to the affected area

63
Q

necrosis

A

tissue death

64
Q

infarct/infarction - name means what

A

name reserved for necrosis as a result of ischaemia (=ischhaemic necrosis)

65
Q

infarcts occurring in certain tissue types

virchow’s triad causing thrombosis and clotting…

A

-Coronary artery thrombosis - infarct in heart
-Cerebral artery thrombosis - infarct in brain
-Mesenteric artery thrombosis - infarct in gut

66
Q

what is an embolism

A
  • A mass of material moving in the vascular system and able to become lodged in a vessel and block its lumen
  • Most emboli are derived from thrombi or clots
  • They break off and go elsewhere in the circulation
67
Q

thromboembolism

A

when thrombi/clots embolise

68
Q

common example of thromboembolism

A

pulmonary embolism

69
Q

how does pulmonary embolism occur

A
  • Sluggish flow in leg veins leads to thrombosis and clot formation
  • Part of thrombus (and clot) breaks off and travels up vein
  • Embolus passes into inferior vena cava, then right heart, then pulmonary trunk, and lodges in pulmonary artery branch
  • Embolus blocks pulmonary artery and get pulmonary infarct
70
Q

breifly outline other forms of embolism

(other than pulmonary embolism)

A
  • marrow embolism (from leg fracture)
  • Air embolism (air entering vein —> air embolism in heart)
71
Q

Give a major example for each situation of Virchow’s triad

A
  1. changes in the intimal surface of a vessel - etheroma lipid coming ont surface
  2. changes in the pattern of blood flow - a bulge of atheroma changing the flow of blood
  3. changes in the blood constituents - smoking making it more likely that platelets aggregate
72
Q

anoxia

A

a state of total oxygen deprivation within tissues or organs - extreme form of hypoxia

73
Q

what kind of problems can ischaemia cause

A
  • Reversiable problem
  • Localised death of tissues (infarction) - permanent
74
Q

sensitive organs to ischaemia

A

brain/kidneys???

LO but not mentioned in power points

75
Q

define circulatory shock

A

profound circulatory failure causing poor perfusion of vital organs

(low blood pressure and its physiological consequences)

76
Q

what does the sringy/elastic property of vessels allow

A

them to collapse when no blood is in them, or open up when blood is present

77
Q

normal arterial blood pressure

A

120/80

78
Q

What does normal blood pressure rely on

A
  1. enough blood in system (about 5L)
  2. smooth muscle in vessels having a certain ‘tone’ (if dec, vessel dialates cause pressure to fall)
  3. heart pumping blood
79
Q

how does the body detect blood pressure and oxygen

A
  • 2 cartoid bodies and 2 carotid sinuses on either side of neck
  • 2 carotid bodies consist of groups of cells which sense the partial pressure of oxygen
  • carotid sinuses respond to blood pressure- sense when it drops and carotid sinuses respond by nerve signals to the brain stem
    -brain stem then tells the heart to pump harder and faster via nerve signals
    => pulse is faster
80
Q

what is the physiological response to low blood pressure

generally

A

Faster pulse (heart rate)

81
Q

What does the brainstem also do (other than inc pulse) to keep someone alive in response to low blood pressure

A
  • sympathetic nervous system stimulation causes increased vascular tone in vessels in limbs and abdomen-> blood pushed up to chest and head
  • results in circulation of remaining blood around heart, lungs and brain- keeps vital organs alive
  • sympathetic nervous system stimulation also causes adrenal glands to secrete adrenaline-> heart pumps even harder and faster
82
Q

when is circulatory shock present

A
  • low blood pressure (60/40)
  • Fast pulse (>100)
83
Q

3 main causes of circulatory shock

A
  1. Hypovolaemic
  2. Septic (infections)
  3. Cardiogenic

also some other less important but possible causes

84
Q

example of hypovolaemic shock

A
  • Rib penetrates spleen and causes major bleed (bleed = haemorrhage)
  • Systemic (arterial) blood pressure normal for a small period of time, but then as blood flows out of damaged spleen less blood is present in other vessels-> vessels collapse as they have no blood in them
  • eventually there is less blood in inferior vena cava which also collapses
  • If inferior vena cava has no blood in it then venous pressure falls to virtually zero
  • Now almost no blood enters the right side of the heart
  • Now very little blood goes through lungs
  • Now very little blood goes to brain and rest of body
  • Systemic blood pressure now drops
  • Carotid sinuses sense lower blood pressure
  • Carotid sinuses upregulate the sympathetic nervous system-> various signs (in addition to low blood pressure)
  • rapid breathing, fast heart rate, pale sweaty skin
85
Q

In hypovolaemic shock (circulatory shock) what does low blood pressure and a high pulse reflect

(relationship between 2)

A
  • Low blood pressure - severe reduction in amound of blood in circulation
  • High pulse - physiological response to low blood pressure
86
Q

what happens in severe septic shock

A

muscle of heart, just like muscle in vessels, also loses it’s tone - may then get slow heart = bradycardia

87
Q

septic shock

A

infection in blood causing genergalised vasodilation and shock

88
Q

complications of shock - organ damage

Key LO

A

1.Brain injury (ischaemic infarction of brain tissue) - initially reversiable but then permanent
2.Decreased perfusion of kidneys à initially reversible, then more severe (ischaemic necrosis of renal tubules)
3.Others…

2. Foundations of Medicine PoD (28 decks)

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