Lecture 5: Vascular Conditions Flashcards

1
Q

What is the conduit system?

A

The Conduit System Transports Soluble Antigens from the Afferent Lymph to Resident Dendritic Cells in the T Cell Area of the Lymph Nodes

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2
Q

Whats the lumen of a blood vessel?

A

Space in the middle of a vessel- where blood flows through

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3
Q

What is the three main layers of a blood vessel?

A

1) tunica intima
2) tunica media
3) tunica externa/adventitia

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4
Q

What is the tunica intima made from?

A

Innerlayer of endothelium &
Internal elastic membrane (supportive connective tissue)

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5
Q

What is the tunica media made from?

A

Middle layer composed mostly of smooth muscle and elastic fibres

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6
Q

What is the tunica externa/adventitia made from?

A

Outer layer of connective tissue

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7
Q

What are distinguishable features of arteries?

A

Thick tunica media & externa layers
High pressure vessels
Carry blood from the heart

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8
Q

What are distinguishable features of capillaries?

A

Tunica intima ONLY
Allows gas, nutrient and waste exchange
Are permeable

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9
Q

What are distinguishable features of veins?

A

Carry blood to HEART
Thin tunica media & externa
Contains valves
Low pressure vessels

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10
Q

What are the two main factors that influence BP

A

CO and TPR (Total peripheral resistance)
BP = CO x TPR

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11
Q

What is CO influenced by?

A

CO is the amount of blood out of a ventricle each minute (mL/min). Its influenced by stroke volume and heart rate.

CO = SV x HR
Stroke volume is the volume of blood pumped out of a ventricle with each beat and heart rate is the number of beats per minute of the ventricles

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12
Q

What is TPR and what is it influenced by? (3)

A

TPR is all of the resistance (friction) that blood will encounter as it flows through the entire vascular circuit.

TRP is influenced by three main things-
1) Blood viscosity
2) The length of the blood vessels
3) The diameter of blood vessels (blood vessel diameter is the most significant factor affecting TPR.)

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13
Q

What would the body do to increase low BP?

A

Release of ADH and increased water absorption
Increased HR
Increased sympathetic activity
Vasoconstriction
Increased heart contractility
Release of aldosterone and increased sodium reabsorption

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14
Q

What would the body do to decrease high BP?

A

Increased urinary excretion
Decreased HR
Vasodilation
Increased parasympathetic activity
Release of ANP

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15
Q

What helps the blood flow through the venous system get back to the heart?

A

Respiratory pump
Muscular (skeletal) pumps
Sympathetic nervous system
Renin-angiotensin aldosterone system (RAAS)- (is the system of hormones, proteins, enzymes and reactions that regulate your blood pressure and blood volume on a long-term basis)

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16
Q

How does the extrinsic mechanism respiratory pump help the blood get back to the heart?

A

The process ofbreathing alternatelyincreases and decreases abdominal pressure-thereby increasing the pressure against blood vessels in the abdomen, squeezing them andforcing blood in the veins to move towards the heart.

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17
Q

How does the extrinsic mechanism sympathetic nervous system help the blood get back to the heart?

A

Sympathetic innervation of the tunica media of the veins stimulates vasoconstriction, reducing the diameter of the veins, and therefore increasing vascular resistance, and consequently blood pressure- facilitating an increase in the pressure gradient to better drive blood back towards the atria.

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18
Q

How does the extrinsic mechanism muscular (skeletal) pumps help the blood get back to the heart?

A

When skeletal muscles contract, they also squeeze nearby blood vessels helping to force blood to flow through the veins.This is particularly important in the veins of the lower limbs.

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19
Q

How does the extrinsic mechanism Renin-angiotensin aldosterone system (RAAS) help the blood get back to the heart?

A

Angiotensin II, a chemical released as part of this system, also stimulates vasoconstriction to increase vascular resistance and therefore blood pressure to help blood return to the heart.

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20
Q

Whats blood stasis?

A

Blood pooling, or decreased/ no flow

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21
Q

What is Arteriosclerosis?

A

Is a type of vascular disease where the blood vessels carrying oxygen away from the heart (arteries) become damaged from factors such as high cholesterol, high blood pressure, diabetes and certain genetic influences.

Arteriosclerosis is the thickening and hardening of the walls of arteries. This occurs due to the migration of smooth muscle cells and collagen fibres into the tunica intima with subsequent mineral deposition. Progressively this narrowsthe lumen of the artery.

Arteriosclerosis occurs as part of the normal aging process, but may also occur in association with hypertension, decreased tissue perfusion, weakening and/or other damage of arterial walls.

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22
Q

What is atherosclerosis?

A

Atherosclerosis is the most common type of arteriosclerosis and occurs when intra-arterial fat and fibrin deposits form within the vessel wall which subsequently harden over time. Atherosclerotic plaques can form as a result of inflammation due to endothelial damage and the accumulation of LDL cholesterol within the tunica intima.

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23
Q

What is cholesterol?

A

Required for steroid hormone synthesis + part of cell membrane.

Cholesterol is a type of lipid, and a key substance required by the body. Cholesterol can be obtained from the diet, but also made by the liver. Cholesterol (and other lipids) are transported in the blood by lipoproteins, of which there are different classes
- Chylomicrons
- Very low density lipoproteins (VLDL)
- Low density lipoproteins (LDL)
- High density lipoproteins (HDL)

24
Q

What is the role of Chylomicrons?

A

Transport triglycerides and cholesterol from intestines after absorption.

25
Q

What is the role of Very low density lipoproteins (VLDL)?

A

Transport triglycerides (and some cholesterol) from liver to adipose tissue & muscles

26
Q

What is the role of Low density lipoproteins (LDL)?

A

Transport cholesterolto body tissues. Main cholesterol carrier (Bad cholesterol lipoprotein)

LDLsare pro-atherogenic. This is because LDLs will readily move into/through blood vessel walls where they can be oxidized

27
Q

What is the role of High density lipoproteins (HDL)?

A

Transport cholesterol back to liver. Good cholesterol lipoprotein. Made in liver. May clear cholestrol from atheroclerotic. Plaque

HDLs are anti-atherogenic

28
Q

What does the inflammatory process within the tunica intima lead to?

A
  • Reductions inanti-coagulants, thus increasing coagulation
  • Reductions invasodilatory factors, thus resulting in vasoconstriction
  • Increased WBC, particularly monocyte,infiltration of the blood vessel

The injured endothelium permits increased amounts of LDLs into the tunica intima, which accumulate. Inflammatory chemicals are released which then result in the oxidation of these LDLs. Monocytesbecomemacrophages and actively engulf the oxidized LDLs, formingfoam cells. An accumulation of foam cells results in a fatty streak within the tunica intima.

29
Q

What can atherosclerosis cause?

A
  • angina pectoris&myocardial infarction
  • transient ischemic attack (TIA)& stroke
  • aneurysm
  • peripheral artery disease
  • gangrene
30
Q

What is Peripheral artery disease?

A

Peripheral artery disease is a type ofperipheral vascular disease (PVD)caused by atherosclerosis within arteries of the limbs, especially the lower limbs. It is commonly associated withdiabetes and coronary artery disease and has the same risk factors as atherosclerosis.

31
Q

Arterial atherosclerotic obstruction in PAD can be gradual or acute. It can be asymptomatic, or may present with what symptoms?

A
  • intermittent claudication: pain/cramping in the lower limbs when moving/exercising
  • changes in skin of lower limb (e.g. temperature, colour, appearance)
  • leg ulcers
  • weak or undetectable pulse in legs or feet
  • severe pain with acute occlusion
  • gangrene
32
Q

What is deep vein thrombosis?

A

Thrombosis is a pathological formation of a blood clot (thrombus) within an intact vessel. This can occur in either arteries or veins, but is more common in veins. The thrombus partially (or completely) occludes the lumen of the vessels- in arteries this can cause tissue ischemia/infarction and in veins can cause localized inflammation.

33
Q

What is the three main factors which promote the formation of deep vein thrombosis?

A
  1. Endothelial injury
  2. Blood stasis
  3. Hypercoagulability

The following are some risk factors that can enhance one or more of the three main factors promoting DVT formation:
- surgery
- immobilization
- obesity
- dehydration
- smoking
- coagulopathies
- pregnancy

34
Q

What are the symptoms of DVT?

A

Localized signs of inflammation (warmth, redness, swelling and pain) and/or oedema of the affected limb.

Many DVTs will resolve on their own due to the breakdown of the clot, however, some DVTs may become organized and remain within the vessel- potentially becoming incorporated into the vessel wall and/or recanalising. DVTs also carry the risk of becoming dislodged and forming anembolus.

35
Q

Whats an Embolism?

A

An embolism occurs when anembolusgets stuck in an arteryit is too small to pass through, thus occluding blood flow. There are two main types of embolism- Systemic/arterial or Pulmonary

36
Q

What is an systemic/arterial embolism?

A

an embolus originating within the left side of the heart or a larger systemic artery gets stuck in a smaller systemic artery.

While an arterial embolism can occur in any systemic artery, common locations include:

  • arteries of the lower limbs, leading to arterial insufficiency & tissue ischemia (presents similar to PAD)
  • coronary arteries, leading to myocardial infarction
  • cerebral arteries, leading to TIA or stroke
37
Q

What is a pulmonary embolism?

A

occurs when an embolus originatingfrom within the right side of the heart or the systemic venous system gets stuck in a pulmonary artery. The most common cause of a pulmonary embolism is a dislodged DVT.

The dislodged DVT (now an embolus) travels through progressively larger and larger veins, into the IVC and the right side of the heart, where it is then pumped into the pulmonary trunk and arteries. From here, the embolus will travel through progressively smaller and smaller pulmonary arteries until it gets stuck in one.

The severity of the pulmonary embolism will be determined by the size of the embolus, and therefore the size of vessels it lodges within and the amount of pulmonary blood flow obstructed. Pulmonary embolism can lead to pulmonary infarction and be life threatening.

Small pulmonary embolism may go unnoticed and may resolve on their own. If more severe, signs and symptoms may include:

  • chest pain
  • sudden cough
  • coughing up blood or bloody mucus
  • increased respiratory rate
  • increased or erratic heart rate
  • sudden onset of shortness of breath
  • shock
  • collapse

Large pulmonary embolism

Pulmonary embolism can have a rapid impact on cardio-respiratory functioning, leading to pulmonary hypoxia and vasoconstriction, pulmonary hypertension & oedema and alterations in normal cardiac function including palpitations and arrhythmias. These can lead to respiratory and/or cardiac failure and death.

Treatment for embolism includes anticoagulants and/or thrombolytics. If recurrent or chronic pulmonary embolism is related to DVTs, vein filters may be inserted to prevent further clots reaching the lungs.Embolectomymay be used as a last resort.

38
Q

What is lipoproteins?

A

Carry cholesterol to and triglycerides (fat) in blood as these are insoluble in plasma.

Made of proteins, phospholipids, cholesterol and triglycerides

39
Q

What does is the purpose of lipoprotein triglyceride?

A

Triglycerides- Triglycerides are a type of fat (lipid) found in your blood. When you eat, your body converts any calories it doesn’t need to use right away into triglycerides. The triglycerides are stored in your fat cells. Later, hormones release triglycerides for energy between meals.

Used in energy metabolism
3 fatty acids + glycerol molecule

40
Q

What does is the purpose of lipoprotein phospholipids?

A

Phosphate head + lipid tail
Major component of cell membranes
Myelin sheath of axons

41
Q

What is hypercholesterolaemia?

A

Elevated blood cholesterol from elevated lipoproteins

Need to consider ratio LDL (bad) and HDL (Good)

Influenced by- Nutrition, genetics, metabolic disease, drugs

42
Q

What is the healthy range of cholesterol?

A

Total cholesterol less than 4mmol/L

43
Q

What is the healthy range of LDL cholesterol?

A

Less than 2mmol/l

44
Q

What is the healthy range of HDL cholesterol?

A

Greater than 1mmol/l

45
Q

What is the healthy range of triglycerides?

A

Less than 1.7mmol/l

46
Q

What ratio of LDL and HDL is dangerous?

A

Greater than 4:1

47
Q

What ratio of LDL and HDL is more healthy?

A

Less than 3:1

48
Q

For total cholesterol what is desirable levels

A

less than 4mmol/l

49
Q

For total cholesterol what levels increase risk?

A

4 to 6.4mmol/l

50
Q

For total cholesterol what levels are high risk?

A

Greater than 6.5mmol/L

51
Q

What can atherosclerosis cause?

A

PAD
Acute arterial occlusion
Aneurysm

52
Q

Whats an acute arterial occlusion?

A

Occurs if platelets attach to plaque and clot forms

Symptoms depends on what vessel is effected

Can include- MI, ischemic stroke, gangrene, infarction of any affected body tissue.

53
Q

What is a thrombosis?

A

Blood clot attached to vessel wall. E.G DVT.
Detached= Thrombo-embulus

54
Q

What are signs and symptoms of DVT?

A

Tenderness in calf
Pain in leg
Swelling of leg
Increased warmth
Red/Blue leg
Discomfort when pulled upward

55
Q

What is an embolism?

A

Obstruction of vessel via embolism

1) Dislodged thrombus
2) Air bubble - IV lines / gun shot
3) Amniotic fluid aggerate
4) Bacteria cancer cells (clump of)
5) Fat cells- Broken long bones
6) Foreign substance

56
Q

What are symptoms of a pulmonary embolism?

A

Chest pain- under the breast bone or on one side. May feel sharp of stabbing. May also be described as burning, aching, or dull, heavy sensation