Physiology: Heart And Circulation

Front 1

systolic blood pressure:

diastolic:

mean arterial blood pressure is highest in ____. It sharply decreases in _______ and even more in ________. It is lowest upon _______.

Back 1

the highest pressure attained in the aorta andperipheral arteries when blood is ejected by the ventricles into theaorta

the lowest pressure attained during relaxation ordiastolic phase of the heart

aorta and large arteries (100), small arteries and arterioles (30), capillaries and small veins (15), entering the right atrium (5)

Front 2

2 ways for heart to control blood pressure:

Back 2

cardiac output (stroke volume x HR) and vasoconstriction/ dilation --> also known as peripheral resistance or PR

Front 3

Blood Pressure is sensed and then controlled by:

Peripheral Resistance is regulated by:

Back 3

baroreceptors (neurons) in the carotid sinuses andarch of the aorta. They send impulses to the cardiovascular centers inthe brain stem/ medulla oblongata which then send signals back to the peripheralvasculature and heart

Change in the diameter of arterioles, controlled y the vasomotor centerof the medulla oblongata

Front 4

Steps of increased cardiac output:

Back 4

Increased blood volume entering heart (e.g. from exercise) --> Increased stretch of myocardial fibers (aka increased pre-load - Frank starling law) --> Greater force of myocardial contraction --> Greater stroke volume --> Increased cardiac output

Front 5

mechanism regulating cardiac output by inhibiting SA node

Back 5

Cardiac output increases --> Blood pressure rises --> Baroreceptors in aortic arch and carotidsinuses are stimulated --> Sensory impulse tocardiac center --> Parasympathetic impulse to theheart --> S-A node inhibited --> Heart ratedecreases --> Blood Pressure return to normal

Front 6

mechanism regulating BP by dilating arteries:

Back 6

Rising blood pressure --> Stimulation of baroreceptorsin aortic arch and carotid sinuses --> Sensory impulses to vasomotor center --> Vasomotor center inhibited --> Less frequentsympathetic impulse to arteriole wall (same as parasympathetic) --> Vasodilation of arterioles --> Decrease peripheralresistance --> Blood pressure returns towards normal.

Front 7

renal control of blood pressure

Back 7

Reduced blood flow to kidneys --> Kidneysreleases renin --> Renin leads to the productionof angiotensin II --> Angiotensin II causes vasoconstriction --> Blood pressure elevated --> Increase blood flow to the kidneys.

Front 8

7 risk factors for stroke:

Back 8

1. Alcohol consumption (increase BP by constricting arteries)

2. Diabetes (constrict arteries)

3. Elevated serum cholesterol (blood is too viscous = elevated BP, they also form plaque

4. Family history of cardiovascular disease (plaque)

5. Hypertension

6. Smoking (constricts, raises BP)

7. Transient ischemic attacks - sudden numbness in hands/ feet, loss of consiousness

Front 9

4 drugs to treat hypertension:

Back 9

Angiotensin – converting enzyme inhibitors:Block formation of Angiotensin II, preventingvasoconstriction.

Beta blockers: lower heart rate.

Ca++ channel blockers: Dilate blood vessels bykeeping Ca ++ ions out of muscle cells in vesselwalls.

Diuretics: increase urine output, lowering bloodvolume.

Front 10

Atherosclerosis:

Back 10

 Atherosclerosis of arteries can occlude blood flow to the heart andbrain and is a causative factor in up to 50% of all deaths in U.S.A.,Europe, and Japan.

 A. Atherosclerosis begins with injury to the endothelium, themovement of monocytes and lymphocytes into the tunica internaand the conversion of monocytes into macrophages that engulflipids. Smooth muscle cells then proliferate and secrete extracellular matrix.

Front 11

Atherosclerosis continued:

Back 11

B. Atherosclerosis is promoted by such risk factors as smoking,hypertension, and high plasma cholesterol concentration.

LDLs which carry cholesterol into the artery wall, are oxidized bythe endothelium and are a major contributor to atherosclerosis.

Front 12

Atherosclerosis continued:

Back 12

Occlusion of blood flow in the coronary arteries by atherosclerosis mayproduce ischemia of the heart muscle and angina pectoris, which maylead to myocardial infarction.

The EKG can be used to detect abnormal cardiac rates, abnormalconduction between the atria and ventricles, and other abnormalpatterns of electrical conduction in the heart

Front 13

Arteries: Blood vessels that carry blood away from the heart to thelungs and tissues.

Arterioles are small arteries that deliver blood to thecapillaries, and because of their small diameter, they play a key role invasoconstriction and vasodilatation.

Most arteries and arterioles carryoxygenated blood, except the pulmonary arteries where they transportdeoxygenated blood from RV to the lungs.

Back 13

see other side

Front 14

Capillaries:

Back 14

Microscopic blood vessels that allow the exchange ofnutrients and wastes between blood and tissues.

This exchange is afiltration process enforced by hydrostatic pressure (created by watermolecules in blood plasma) and osmotic pressure (created by plasmaproteins, particularly albumin).

Front 15

Veins: blood vessels that carry blood to the heart, from the lungsand tissues. Blood pressure in veins is extremely low, as a resultvalves formed by the tunica internal layer are necessary toprevent backflow. Most veins carry deoxygenated blood, except thepulmonary veins where they transport oxygenated blood from the lungsto the left atrium. Venules are small veins that are formed by the unionof several capillaries.

Back 15

see other side

Front 16

walls of arteries:

capillaries connect _______ and ______ and the wall forms a _______.

Back 16

The walls of arteries and arterioles consist of layers ofendothelium, smooth muscle, and connective tissue.

Autonomic fibers that can stimulate vasoconstriction orvasodilatation innervate smooth muscles in vessel walls.

Capillaries: connects arterioles and venules. The capillary wallis a single layer of cells that from a semi-permeable membrane.

Front 17

openings in capillary walls are ________. The size of these varies tissue to tissue. In the brain, these cells are _____, forming ______, through which substances must move through ______.

What regulates capillary blood flow and how?

Back 17

thin slits between endothelialcells. Endothelial cells of brain capillaries are tightly fused, forming ablood – brain barrier through which substances move by facilitateddiffusion.

precapillary sphincters open when cells are low inO2and nutrients, and closewhen cellular needs are met.

Front 18

In capillary exchange, ______ is the most important means of transport. These pathways depend on lipid solubility. ______ generally remain in the blood. _________ = filtration, which causes net movement of fluid out of the capillary at the ______ end.

Back 18

diffusion, plamsa proteins, hydrostatic pressure, arteriolar

Front 19

_______ causes a net inward movement of fluid at the _______ end of the capillary. This is created by a difference in pressures caused by _______.

excess tissue fluid is returned to the _______ by __________. ________ occurs when excess tissue fluid accumulates.

Back 19

Osmotic pressure, venular, plasma proteins in blood

venous system by lymphatic vessels, edema

Front 20

velocity of blood flow is inversely related to ________. The movement of blood is also called hemoynamics

Back 20

the totalcross – sectional area of blood vessels, where the larger the total area,the slower the velocity. [capillaries, as a group, make up the largesttotal cross – sectional area in the cardiovascular system, as a resultallow the slowest velocity of blood flow].

Front 21

Blood flow is affected by:

R refers to the opposition toblood flow due to frictionbetween blood and (3). it iscalculated based on thefourth power of the radius ofblood vessel: ________. Thisequation indicates that thesmaller the radius, the larger the resistance to blood flow

Back 21

blood pressure and resistance

blood vessel walls, blood clots, other resisting factors, R = 1/r^4

Front 22

Blood volume:

Peripheral Resistance:

Viscosity:

Back 22

The sum of all blood cells and blood plasma volume.About 5 liters in an average person

Friction between blood flow and blood vesselwalls produces resistance that affect blood flow and blood pressure

Higher viscosity of blood (thicker blood) causes morefriction in blood flow, resulting in more resistance.

Front 23

Blood Pressure:

Arterial Blood Pressure:

Back 23

the force blood exerts against the insides ofblood vessels.

The arterial blood pressure is produced primarily by heartaction and rises and falls with phases of the cardiac cycle.

b. systolic pressure occurs when the ventricle contracts;diastolic pressure occurs when the ventricle relaxes.

Front 24

Factors that influence arterial blood pressure:

Back 24

a. Heart action, blood volume, resistance to flow, and bloodviscosity influence arterial blood pressure.

b. Arterial blood pressure , as cardiac output, blood volume,peripheral resistance, or blood viscosity increases.

Front 25

The ______ of the ______ regulates heart rate.

review slide 17

Back 25

cardiac center of the medulla oblongata

Front 26

venous blood flow is not a direct result of heart action; itdepends on:

Explain how breathing affects venous blood flowL

Back 26

skeletal muscle contraction, breathing movementand venoconstriction.

pressure changes during breathing due to abdominal pressurecreates a respiratory pump that sucks blood up ward toward theheart.