Physio Lecture 15 (Exam 3)

Front 1

What are the three main factors of peripheral resistance?

Back 1

1. Vessel diameter 2. Blood
viscosity 3. Total vessel length.

Front 2

How do changes in blood vessel diameter affect flow rate?

Back 2

If the diameter of a vessel were to double in size (ie from 1mm to 2mm), the flow rate would increase by 16 times; this is because the resistance decreased by 16 fold (there is less interaction of the blood with the walls of the vessel).

Front 3

What is Mean Arterial
Pressure (MAP)?

Back 3

It is the average pressure “seen” by organs in the body – it accounts for the fact that the heart is cycling between systole and diastole.

Front 4

How is MAP calculated?

Back 4

MAP = Diastolic pressure + 1/3Pulse Pressure; The Pulse pressure = (Systolic pressure -
Diastolic pressure).

Front 5

Why is MAPan important value?

Back 5

The pressure difference across the capillary bed (organ) controls the flow rate through the capillary bed, this needs to be
maintained at a constant rate to ensure proper exchange of nutrients and gases and
removal of waste products.

Front 6

Why does stroke volume decrease as mean arterial pressure increases above normal?

Back 6

To compensate for an increase in MAP, the stroke volume will
decrease to return the MAP back to "normal".

Front 7

Is the cerebral circulation controlled by sympathetic activity?

Back 7

no

Front 8

What is the major controlling factor of cerebral circulation?

Back 8

Intrinsic controls (from the brain tissue itself). The vessels will constrict is too much pressure is sensed, and with increased metabolic
activity which will cause release of molecules such as CO2 and ADP, there will be
localized areas of vasodialation.

Front 9

Does the flow of blood to the brain vary significantly?

Back 9

No, it is maintained at about 760ml/min without much variation

Front 10

Is the blood pressure the same in all vessel types?

Back 10

no

Front 11

Which vessel types have the lowest blood pressure?

Back 11

Veins directly leading to the heart.

Front 12

Which vessel types have the highest blood pressure?

Back 12

Arteries leading away from the heart

Front 13

Which
vessels have the strongest walls?

Back 13

major arteries

Front 14

Which vessels have the most recoil?

Back 14

major arteries

Front 15

Which vessels have the thinnest walls?

Back 15

capillaries

Front 16

Which vessels have no smooth muscle layer?

Back 16

capillaries

Front 17

Is the diameter of capillaries adjustable by the sympathetic n. s.?

Back 17

No, the capillaries
themselves do not have smooth muscle, however, the precapillary sphincters are
controlled by the sympathetic nervous system, and they ultimately control the amount of blood flow to the capillaries

Front 18

Do all vessels exchange nutrients and gasses through their walls to the surrounding
interstitial fluid?

Back 18

No, the only real exchange occurs in the capillaries

Front 19

Do all vessels have valves?

Back 19

no

Front 20

Do all vessels have smooth muscle around them? )

Back 20

All vessels EXCEPT capillaries have smooth muscle, although the amount of smooth muscle
varies tremendously. (Note – the slide in class looks as though there is no smooth muscle around the venules, however, they DO have smooth muscle around them – but they have
a miniscule amount compared to the other types of vessels.

Front 21

What type of vessel has the greatest potential resistance to blood flow?

Back 21

Arterioles.

Front 22

Is blood flow to each organ equal?

Back 22

no

Front 23

Is blood flow to each organ constant?

Back 23

No, except to the brain and heart (these two organs receive a fairly constant flow rate)

Front 24

How is blood flow to each organ
regulated?

Back 24

by the sympathetic tone and local mediators of vasodialation/vasocontriction

Front 25

What are precapillary sphincters and how are they regulated?

Back 25

The precapillary sphincters
are smooth muscle "bands" that are found at the beginning of the capillary beds. They
can be stimulated to constrict by the sympathetic nervous system and when constricted
will reduce blood flow to that particular region of the capillary bed (and organ).

Front 26

How are intrinsic and extrinsic controls of arteriole diameter different?

Back 26

Intrinsic controls
of arteriole diameter are produced by the vessel itself, they include the myogenic
properties of the arterial wall, the amount of O2, CO2, and NO in the blood etc., these
intrinsic controls affect only a localized area. The extrinsic controls refer to the amount
of sympathetic tone that the vessels are receiving and are systemic in nature.

Front 27

What metabolic by-products or physical conditions during activity promote arteriole
dilation?

Back 27

Either decrease O2 levels in the blood; or increase levels of ADP, CO2 or NO in the blood.

Front 28

Does the heart normally use anaerobic or aerobic metabolism, or both?

Back 28

It uses both

Front 29

What set of vessels within the walls of the heart supplies blood to heart cells?

Back 29

Coronary arteries. (FYI- ~85% of blood flow is delivered to the heart by the left coronary artery.)

Front 30

Does the heart wall receive more blood during systole or diastole?

Back 30

It receives most of its
blood (70%) during diastole, because during systole, the vessels are being compressed

Front 31

What is the sympathetic effect on the coronary arterioles?

Back 31

Vasodialation

Front 32

Besides the
sympathetic n. s. what else has a vasodilating effect on coronary vessels during exercise?

Back 32

Local mediators i.e. decreased O2, increased CO2, increased NO, increased Adenosine
(this is fairly specific to the coronary vessels).

Front 33

What is angina pectoris?

Back 33

Chest pain

Front 34

What is ischemia?

Back 34

Insufficient blood supply to any
tissue.

Front 35

Are angina pectoris and ischemia correlated?

Back 35

Yes, when the heart is ischemic, it is often accompanied
by angina pectoris.

Front 36

What is a myocardial infarction?

Back 36

after a minute or two of ischemia,
heart cells begin to die; this is myocardial infarction - the clinical term for a heart attack

Front 37

What is the main cause of CAD, coronary artery disease?

Back 37

Atherosclerosis

Front 38

What is atherosclerosis?

Back 38

Progressive, gradual blockage of the blood vessels, due to
deposits of lipids in the vessel walls.

Front 39

What risk factors are correlated with atherosclerosis?

Back 39

High levels of LDL, smoking, family history of either atherosclerosis or high levels of LDL, diabetes

Front 40

What are atheromas?

Back 40

plaque of lipid deposit in the vessel wall

Front 41

What is a a thrombus?

Back 41

a blood clot that forms at the site of the atheroma

Front 42

What is an embolus?

Back 42

a dislodged thrombus

Front 43

What is an an angiogram?

Back 43

a clincal procedure in which a dye is injected into a persons blood stream so that the
vessels of the heart can be vued

Front 44

What is an angioplasty?

Back 44

surgery, in which a catheter is directed down a blocked vessel (generally of the heart) to a narrowed area, which is then widened by a
balloon, that inflates and stretches the area open

Front 45

what is a stent?

Back 45

a small piece of tubing
which is then placed in the artery to help keep it open after the angioplasty has been done.

Front 46

Systole

Back 46

Period of cardiac contraction and emptying

Front 47

Diastole

Back 47

Period of cardiac relaxation and filling

Front 48

Viscosity

Back 48

Thickness of blood due to RBc’s, The friction developed between molecules of a fluid as they slide over each other during flow of the fluid, greater the viscosity the greater the resistance to flow, contributes to peripheral resistance, must lower in the capillaries that in the rest of the system since RBC’s line up in single file to pass thru them

Front 49

Poiseuilles Law (equation and variables)

Back 49

Describes factors affecting laminar blood flow, πΔPr4/8Lη blood pressure, vessel radius, vessel length, blood viscosity

Front 50

MAP, Mean Arterial Pressure (120/80  93 mmHg)

Back 50

The difference between the arterial and the venous pressure that drives blood through the capillary beds of our organs, found by Diastolic Pressure + 1/3 Pulse Pressure (systolic pressure – diastolic pressure) , the average pressure responsible for driving blood foreward thru the arteries into the tissues throughout the cardiac cycle, equals cardiac output times total peripheral resistance

Front 51

Arteries

Back 51

Vessels that carries blood away from the heart

Front 52

Arterioles

Back 52

The highly muscular high resistance vessels, the caliber of which can be changed subject to control to determine how much of the cardiac output is distributed to each of the various tissues, bulkiest of all vessels

Front 53

Capillaries

Back 53

The thin walled pore lined smallest of blood vessels, across which gas exchange between the blood and surrounding tissues takes place, made up of endothelial cells no smooth muscle around them

Front 54

Venules

Front 55

Veins

Back 55

Vessels that carries blood back to the heart

Front 56

Endothelium

Back 56

The thin, single celled innermost layer of all vessels that lines the entire circulatory system

Front 57

Tunica Externa

Back 57

One of three layers lining arteries and veins, Connective Tissue

Front 58

Tunica Media

Back 58

One of three layers lining arteries and veins, most smooth muscle

Front 59

Vasoconstriction

Back 59

The narrowing of a blood vessel lumen as a result of contraction of the vascular circular smooth muscle, leads to increased resistance and decreased flow through vessel

Front 60

Vasodilation

Back 60

The enlargement of a blood vessel lumen as a result of relaxation of the vascular circular smooth muscle, leads to decreased resistance and increased flow through the vessel

Front 61

Tunica Interna

Back 61

One of three layers lining arteries and veins, made up of endothelium, basement membrane and elastin (stretchy)

Front 62

Elastin

Back 62

Stretchy material found in arteries and veins, not found in arterioles or venules

Front 63

Precapillary Sphincters

Back 63

Actual smooth muscle found between arterioles and capillaries that allows amounts of blood into capillary bed, help direct blood flow, blood flow thru a capillary bed is determined by state of precapillary sphincters of arteriole supplying it

Front 64

LDL (Low density lipoprotein)

Back 64

Low Density Lipoprotein; transport cholesterol and lipids from liver to tissues (too much is bad, b/c if you build up cholesterol and lipids in tissues this leads to plaque build-up), a type of ApoB-100, statins affect this type of lipoprotein in the bloodstream

Front 65

Apo B-100

Back 65

A type of LDL lipoproteins

Front 66

HDL (High density lipoprotein)

Back 66

High density lipoprotein, transports excess cholesterol from tissues and delivers to liver, (healthy, excess cholesterol from tissues its properly disposed of or stored in the liver for future use)

Front 67

Atherosclerosis

Back 67

A progressive, degenerative arterial disease that leads to gradual blockage of affected vessels, reducing blood flow through them, plaque begins at sites of damage to endothelium (from hypertension, smoking, high cholesterol, diabetes), most common form of arteriosclerosis

Front 68

Arteriosclerosis

Back 68

Hardening of arteries so not able to expand and recoil during systole

Front 69

Atheroma

Back 69

A localized plaque that reduces blood flow in an artery, benign (noncancerous) tumors of smooth muscle cells within the blood vessel walls

Front 70

Angiogram

Back 70

Able to show blood flow through vessels by viewing the vessels themselves (black and white picture)

Front 71

Angioplasty

Back 71

Placement of a stent

Front 72

Thrombus

Back 72

An abnormal blot attached to the inner lining of a blood vessel

Front 73

Embolus

Back 73

A freely floating clot, previously a thrombus

Front 74

Stent

Back 74

Placed into artery and expanded to compress plaque against vessel wall to prevent the blocking of blood flow, inserted using a catheter

Front 75

Ischemia

Back 75

Deficient blood supply to the tissues, most commonly due to atherosclerosis in coronary arteries, causes increased lactic acid and anaerobic metabolism, often accompanied by angina pectoris, can lead to possible myocardial infarction

Front 76

Angina Pectoris

Back 76

Chest pain

Front 77

Myocardial Infarction

Back 77

Heart attack, a form of ischemic heart disease, detected by changes in S-T segment of ECG, diagnosed by high levels of creatine phosphokinase and Lactate dehydrogenase

Front 78

Creatine Phosphokinase

Back 78

Enzyme that puts phosphate on creatine molecules to help in ATP, high levels of this indicates myocardial infarction

Front 79

Lactate Dehydrogenase

Back 79

High levels of this indicates myocardial infarction

Front 80

Myogenic Regulation

Back 80

Self spontaneous found in smooth muscle, arteries automatically dilate/constrict due to changes in BP, intrinsic mechanism

Front 81

Metabolic Regulation

Back 81

Intrinsic mechanism that is involved in local neural activity when arterioles are sensitive to increases in activity, areas of the brain with higher metabolic activity receive more blood

Front 82

Cutaneous

Back 82

Skin, which is involved with thermoregulation, skin blood flow is adjusted by arterial dilation/constriction and activity of arteriovenous anastomoses which controls blood flow through surface capillaries

Front 83

Thermoregulation

Back 83

Skin serves as a heat exchanger for regulation of temperature