Exam 3: Control of Blood Flow Presentation

Question 1

Describe acute control of localized tissue regulation

Answer 1

Rapid changes in local vasodilation/vasoconstriction occurs in seconds to minutes.

Question 2

Describe long-term control of local blood flow.

Answer 2

increase in sizes/number of vessels, and can occur over a period of days, weeks, or months.

Question 3

Under what conditions would a vasodilator be released by the tissue?

Answer 3

Low O2 levels or lack of blood supply

Question 4

What is vasomotion?

Answer 4

Cyclical opening and closing of precapillary sphincters.

Question 5

What is hyperemia

Answer 5

an excess of blood in the vessels supplying an organ. Can increase to 4-7x’s the normal limits. Reperfusion can cause damage b/c of the large influx of O2

Question 6

What is autoregulation?

Answer 6

Tissues control how much blood they get/need. So within minutes, blood flow returns to normal even with elevated pressure.

Question 7

What is the Metabolic theory of autoregulation?

Answer 7

Increase in blood → Too much oxygen/nutrients → washes out vasodilators

Question 8

What is the Myogenic Theory of Autogreulation?

Answer 8

Stretching of vessels → reactive vasculature constriction

Question 9

What is the role of NO in vasodilation/vasoconstriction?

Answer 9

Damaged cells block production of NO which inhibits vasodilation creating vasoconstriction.

Question 10

What is humoral circulation control?

Answer 10

What’s in the blood that can control circulation.

Question 11

What four components of circulation control vasoconstriction?

Answer 11

Norepinephrine Epinephrine Angiotensin II Vasopressin

Question 12

What components of circulation control vasodilation?

Answer 12

Bradykinins Histamine

Question 13

T/F the sympathetic nervous system innervates all vessels except capillaries which primarily results in vasodilation.

Answer 13

False, It primarily results in vasoconstriction.

Question 14

What part of the brain is the vasoconstriction area of the brain

Answer 14

Anterolateral Portions of upper medulla

Question 15

What are vasoconstrictor tones?

Answer 15

Continual Firing of vasoconstriction area of brian

Question 16

What are vasomotor tones?

Answer 16

Partial state of contraction of blood vessels due to vasoconstriction are of brain.

Question 17

Where in the brain is the Vasodilation are of the brain?

Answer 17

Bilateral in the anterolateral portions of lower medulla.

Question 18

How does the vasodilation area of the brain function?

Answer 18

It caused vasodilation by inhibiting vasoconstriction at vasoconstriction area of brain in upper medulla.

Question 19

What does the adrenal medulla secrete?

Answer 19

Epinephrine Norepinephrine

Question 20

Neural rapid control of arterial pressure is simultaneously caused by….

Answer 20

Constriction of most systemic arteries ( increases peripheral resistance) constriction of veins, Increased HR.

Question 21

T/F The simultaneous changes that control neural rapid arterial pressure all increase blood pressure?

Answer 21

True, They are 1)Constriction of most systemic arteries 2) constriction of veins 3) Increased heart rate

Question 22

What do baroreceptors do?

Answer 22

Sense pressure changes Stimulated by low arterial pressure Carotid sinus stimulated by pressure <30 mmHg

Question 23

What are the 4 main functions of Baroreceptors?

Answer 23

1) Inhibit vasoconstriction center 2) Excite vasodilator center 3) Signals cause ↑ or ↓ in arterial pressure. 4) 1º Function is to reduce the minute-by-minute variation in arterial pressure.

Question 24

What is the effective range of baroreceptors?

Answer 24

~60-110 mmHg

Question 25

Describe Chemoreceptors.

Answer 25

They are located in common carotids and in aortic bodies. Sensitive to lack of O2, CO2 excess, and H+ ion excess. Play an important role in respiratory control.

Question 26

What are atrial reflexes?

Answer 26

Low pressure receptors located in atria and pulmonary arteries that play important role in minimizing arterial pressure changes in response to changes in blood volume.

Question 27

An increase in atrial stretch reflex results in....

Answer 27

* Reflex dilation of kidney afferent arteriols. * Increase in HR * Signal hypothalamus to decrease ADH. * Atrial Natriuretic peptide (ANP) →Kidneys * Kidneys ↑ GFR and ↓ Na+ reabsorption

Question 28

What is the equation for atrial pressure?

Answer 28

Atrial Pressure = cardiac output x total peripheral resistance

Question 29

Atrial pressure rises when total peripheral resistance is acutely increased. What are two ways normal kidneys return the arterial pressure back to normal within a day or two?

Answer 29

* Pressure diuresis * Pressure Natriuresis (Na+ in urine)

Question 30

What are four major causes of hypertension?

Answer 30

* Renal causes * Endocrine Causes * Cardiovascular causes * Neurologic causes

Question 31

Primary hypertension usually has an unknown origin, what percentage of people who suffer from hypertension have Primary?

Answer 31

90- 95%

Question 32

What is atherosclerosis?

Answer 32

Type of arteriosclerosis that is characterized by lesions within tunica intima that protrude into lumen.

Question 33

A genetic variant in the renin-angiotensis system can lead to what pathology?

Answer 33

Hypertension.

Question 34

Factors resulting in decreased peripheral resistance (vessel dialtion) that can lead to decreased blood pressure would be categorized by what pathology?

Answer 34

Hypotension.

Question 35

What are some factors that can lead to hypotension?

Answer 35

* ↑ production of NO * ↑ release of prostacyclin * ↑ release of kinins * ↑ in atrionatriuretic peptide (ANP) * ↓ neural factors (ß-adrenergic)

Question 36

What are non-modifiable risk factors associated with atherosclerosis?

Answer 36

age, gender, genetics

Question 37

List 3 humoral vasoconstrictiors

Answer 37

* Angiotensin II * Catecholamines * Endothelin

Question 38

List 3 humoral Vasodilators

Answer 38

* Kinins * Prostaglandins * Nitric oxide

Question 39

What are modifiable risk factors associated with atherosclerosis?

Answer 39

* Hyperlipidemia * Hypertension * Cigarette Smoking * Diabetes

Question 40

Name 6 other factors contributing to atherosclerosis.

Answer 40

* Inflammation * Hyperhomocystinemia * Metabolic syndrome * Lipoprotein (a) * Factors affecting hemostasis * Life Style

Question 41

Explain the accumulation of lipoproteins (esp LDL) in atherosclerosis.

Answer 41

1. Lipoprotiens accumulate in the intima & are oxidized by O2 free radicals from macrophages or endothelial cells 2. Macrophages ingest oxidized LDL = foam cells 3. Oxidized LDL stimulates release of growth factors, cytokines, and chemokines 4. Oxidized LDL is toxic to endothelial cells and smooth muscle cells.

Question 42

What are the stages of atherosclerosis formation due to monocyte adhesion to endothelium?

Answer 42

1. Monocytes and T-cells are bound to endothelial cells through expression of VCAM-1 on endothelial cells. 2. Monocytes transform into macrophages and engulf lipoproteins 3. T-cells stimulate a chronic inflammatory response 4. Activated leukocytes and endothelial cells release growth factors that promote smooth muscle cell proliferation.

Question 43

What is a mature atheroma?

Answer 43

a cap of smooth muscle cells, macrophages, foam cells (converted macrophages), and other extracellular components, overlying a necrotic center composed of cell debris, cholesterol, foam cells, and calcium. Garbage pile.

Question 44

What is the process of atherosclerosis Development?

Answer 44

* Earliest lesions are fatty streaks * Plaques impinge on lumen of artery (yellow/white) * Plaques progressively enlarge * plaques often undergo clacificaiton * plaques may rupture, ulcerate, or erode.

Question 45

What are the most common arterial sites for atherosclerosis?

Answer 45

* Lower abdominal aorta * coronary arteries * popliteal arteries * internal carotid arteries * circle of willis

Question 46

How is short term arterial pressure controlled?

Answer 46

* Via SNS on total peripheral vascular resistance and capacitance (cardiac pumping ability)

Question 48

How is long-term arterial pressure controlled?

Answer 48

* Via multiple nervous & hormonal controls * Via local controls in kidney that regulate salt and water excretion *

Question 49

What are the primary determinants of long-term arterial pressure level?

Answer 49

* Degree of pressure shift of the renal output curve for water/salt * level of water/salt intake

Question 50

# Define chronic hypertension.

Answer 50

One's mean arterial pressure is greater than the upper range of the accepted normal measure. Normal = 90mmHg Hypertensive 110 mmHg

Question 51

What is considered severe hypertension?

Answer 51

150-170 mmHg (250/130)

Question 52

What are 5 causes of lethal effects of chronic hypertension?

Answer 52

* Early heart failure * coronary heart disease * heart attack * cerebral infarct * destruction of area of kidneys

Question 53

List 5 characteristics of primary hypertension

Answer 53

* Increased cardiac output * increased SNS activity * Increase in angiotensin II & aldosterone levels * impairment of renal-pressure natriuresis mechanism * Inadequate secretion of water/salt