alterations of cardiovascular fx for week 10

Question 1

Mean arterial blood pressure

Answer 1

MAP= diastolic pressure + 1/3 of the pulse pressure

-pulse pressure = systolic - diastolic pressure

Question 2

Cardiac output

Answer 2

• a measurement of the effectiveness of the heart as a pump

- influenced by blood volume (related to body sodium) and cardiac factors (heart rate, contractility)

Question 3

cardiac output formula

Answer 3

CO = HR x SV

• HR: heart rate is # of beats/minute
• SV: stroke volume is ant of blood ejected in one heartbeat

Question 4

Blood pressure regulation

Answer 4

• kidneys aid in regulating blood pressure
• they influence peripheral resistance and sodium homeostasis
• renin is produced by the kidney and converts angiotensinogen to angiotensin
• angiotensin alters BP by increasing peripheral resistance and blood pressure (via aldosterone)

Question 5

Blood pressure formula

Answer 5

• BP = CO x PR
• BP= blood pressure: the force that causes blood to flow through vessels
• CO= cardiac output: the amount of blood pumped out of one ventricle in one minute
• PR= peripheral resistance: resistance to blood flow created primarily by the arterioles

Question 6

Peripheral resistance

Answer 6

• precapillary sphinctors
• even more important is the vasoconstriction/vasodilation of the arterioles
• w/vasoconstriction: bld flow deceases and bld velocity increases
• total in = total out
• fluid follows path of least resistance

Question 7

Poiseuille’s Law

Answer 7

Q = (P1 - P2) / R

• Q is blood flow
• P is pressure difference
• R is resistance

Question 8

Poiseuille’s Formula

Answer 8

R = (8nl) / pi r^4

• R is resistance
• n is viscosity of the blood
• r is lumen’s radius
• l is length of tube
• Radius is MOST important factor

Question 9

Hypertension is major risk factor for?

Answer 9

• coronary artery disease (heart attack)
• cerebrovascular accidents (stroke)
• both due to atherosclerosis

Question 10

Epidemiology of Hypertension

Answer 10

• 25% of the general public are hypertensive
• blacks are affected twice as often as whites (and seem more vulnerable to the complications of hypertension)
• increased prevalence with increased age

Question 11

Causes of hypertension

Answer 11

• 90-95% of hypertension is idiopathic
• primary or essential hypertension
• two theories:
• decreased renal excretion of sodium
• increased peripheral resistance
• 5-10% is secondary to another condition
• renal disease (largest cause of secondary)
• narrowing of the renal artery (atheromas)
• adrenal or thyroid disorders (excess of thyroid hormone is bad for the heart)
• pregnancy = pre=eclampsia

Question 12

Clinical course for hypertension

Answer 12

-both essential and secondary hypertension may be either benign or malignant

Question 13

benign hypertension

Answer 13

remains at a modest level and fairly stable over a long period of time

Question 14

malignant hypertension

Answer 14

severe, rapidly developing hypertension; if untreated, leads to death within one or two years

Question 15

more on malignant hypertension

Answer 15

• diastolic pressure often > 120 mmHg
• renal failure and/or retinal hemorrhages often occur in malignant hypertension
• can lead to cerebral edema, CHF, etc.
• may develop in previously normotensive people
• more often superimposed on preexisting benign hypertension (primary or secondary)

Question 16

Factors involved in the development of hypertension

Answer 16

• obesity
• smoking
• heavy consumption of salt
• atherosclerosis
• caffeine

Question 17

obesity involvement in the development of hypertension

Answer 17

increases peripheral resistance and increases workload on the heart

Question 18

smoking involvement in the development of hypertension

Answer 18

increases heart rate and stimulates vasoconstriction

Question 19

heavy consumption of salt involvement in the development of hypertension

Answer 19

increases blood volume

Question 20

atherosclerosis involvement in the development of hypertension

Answer 20

increases peripheral resistance

Question 21

caffeine involvement in the development of hypertension

Answer 21

CV & respiratory stimulant; also leads to vasoconstriction

Question 22

possible complications of hypertension

Answer 22

• hypertension significantly increases the workload on the heart
• also puts physical stress on the walls of the blood vessels throughout the body
• also increases risk of other heart issues

Question 23

hypertension significantly increases the workload on the heart

Answer 23

• left ventricle gradually enlarges (causes hypertrophy)
• more muscle mass means a greater oxygen demand
• if coronary circulation can’t keep pace, symptoms of cardiac ischemia appear (heart attack)

Question 24

hypertension also puts physical stress on the walls of the blood vessels

Answer 24

• promotes the development of atherosclerosis (by creating endothelial damage)
• increases the risk of stroke and/or myocardial infarction (by creating thromboembolic in response to endothelial damage)
• increases risk of aneurysms

Question 25

Hypertension also increases the risk of

Answer 25

- congestive heart failure by increasing after load (what heart has to pump into) - aneurysms by straining the blood vessels and causing tears in the endothelium - renal failure since the kidney's arterioles thicken in response to the stress of increased pressure; lumens become narrower; renal perfusion declines

Question 26

hypertension increases risk for other issues aside from CHF, etc.

Answer 26

- impaired vision: by damaging retinal vessels - edema: by hydrostatic mechanisms - impaired mobility & exercise intolerance: heart is in a work overload situation even at rest, so additional work is not tolerated

Question 27

Aneurysm

Answer 27

a bulge in the weakened wall of an artery - most dangerous aneurysms are those involving arteries of the brain and aorta * aneurysms in the brain can cause strokes * ruptured aortic aneurysms will cause fatal hemorrhage in a matter of minutes

Question 28

causes of aneurysms

Answer 28

- atherosclerosis is by far the most common cause of aneurysms - over time atherosclerosis causes * vessel walls to become less elastic * plaque formation erodes the vessel wall * underlying tunica media becomes destroyed and thus weakens the wall

Question 29

false aneurysms

Answer 29

- actually a bruise/hematoma - false aneurysms break in the vessel wall but blood is contained by a clot - dissecting aneurysm is a break in vessel wall, but blood is contained by adventitia - both often due to trauma

Question 30

Aortic Dissection

Answer 30

- blood makes its way between the layers of the aortic wall, separating them - can be up to 25 cm in length - thrombi often form in the outputting area

Question 31

Diverses of the veins

Answer 31

- varicose veins - venous stasis ulcers - deep vein thrombosis

Question 32

Varicose vein definition

Answer 32

a vein in which blood has pooled, producing an abnormally dilated, tortuous vein

Question 33

varicose veins caused by

Answer 33

- trauma to the saphenous vein that damages one or more valves - gradual venous distention caused by a combination of standing for long periods and the pull of gravity (genetically weak valves)

Question 34

what kinds of valves are most affected by varicose veins

Answer 34

-superficial veins of the legs are the most frequently involved since there is less muscle mass around them so they have a harder time moving up

Question 35

valve incompetence risks

Answer 35

- age - females - family history - obesity - pregnancy - standing for long periods

Question 36

Pathogenesis of varicose veins

Answer 36

- blood pooling in the superficial veins leads to increased hydrostatic pressure, stretching the veins and causing edema - venous valves are overloaded and become incompetent - incompetent valves lead to worsened venous stasis and further increase in intraluminal pressure - tese veins often thrombus, but because they are superficial it is uncommon that they travel to the lungs

Question 37

hemhorrhoids

Answer 37

result from dilation of the veins at the anorectal junction

Question 38

esophageal varices

Answer 38

usually in patients with cirrhosis of the liver (hepatic portal hypertension)

Question 39

pregnancy

Answer 39

increased fluid volume

Question 40

venous stasis ulcers

Answer 40

- chronic venous insufficiency - circulation to the extremities is so sluggish that metabolic needs for oxygen, nutrients, and waste removal are barely met - risks: immobility, obesity, age, L heart failure, varicose veins - results in cell death and necrosis *chronic inflammation *edema, hyperpigmentation

Question 41

Deep vein thrombosis

Answer 41

- thrombi which arise in the deep veins of the legs (more likely -> thromboemboli) - usually are silent clinically - have potential to give rise to pulmonary embolism and infarction - often results as a complication of orthopedic or obstetric procedures - up to 65% of patients w/ lower extremity trauma -> DVT - venous thrombi are more common than arterial thrombi in the legs (due to skeletal muscle pump)

Question 42

factors which promote venous thrombosis

Answer 42

- venous stasis - vessel damage - hypercoaguability

Question 43

venous stasis

Answer 43

cause by immobility, age, and left heart failure

Question 44

vessel damage

Answer 44

caused by trauma or IV medications

Question 45

hypercoaguability

Answer 45

caused by pregnancy, oral contraceptives, coagulation disorders, and some cancers

Question 46

clinical manifestations of deep vein thrombosis

Answer 46

- markedly different from those of arterial thrombosis (hypoxia is present in arterial but indirectly present in venous) - skin is discolored - red to deep purple - edema is prominent (hydrostatic venous back pressure) - pain - especially at the site of the occlusion - neuralgia if edema compresses local nerves