Lecture 13 3/11/14

Question 1

Blood Flow

Answer 1

the amount of blood flowing through a vessel or organ per given unit time. We can decrease or increase blood flow.

Question 2

Two factors affecting flow rates

Answer 2

Pressure and Resistance

Question 3

Q = P/R

Answer 3

Flow Dynamics or Ohm’s Law.

Question 4

Q stands for what?

Answer 4

Blood Flow

Question 5

P stands for what? And what is the definition?

Answer 5

Pressure. Stress exerted on a vessel wall as blood flows through it.

Question 6

Q & P are proportional or disproportional? How?

Answer 6

Proportional. If we increase pressure, we’ll increase flow, if we increase flow rate, we’ll increase pressure

Question 7

R stands for what? And what is the definition?

Answer 7

Resistance. Disproportional to blood flow. Increase in resistance will decrease blood flow.

Question 8

Rules Regarding Pressure

Answer 8

1) Pressure is directly proportional to the flow rate or to that blood flow.
2) Fluid flows from higher pressures to lower pressures. It has to.
3) Greater the difference in pressure, the faster the flow rate.

Question 9

MAP

Answer 9

Mean Arterial Pressure or the average pressure

an average blood pressure per given unit of time within that vessel. The key is average.

Full cycle is one second long. Only 2/10 vessel walls is exposed to the high pressure or 20%.

Equation is Diastolic + (Systolic - diastolic/3) = MAP should be around the 90’s.

Pulse pressure is the (Systolic Pressure - Diastolic Pressure). Hypertension or borderline Hypertension is around the 100’s.

Question 10

Aorta Pressure

Answer 10

100 mmHg - The highest

Question 11

Right Atrium Pressure

Answer 11

0-1 mmHg - The lowest

Question 12

Three Factors Affecting Resistance

Answer 12

1) Vessel Diameter
2) Fluid Viscosity
3) Turbulence

Question 13

Vessel Diameter

Answer 13

if there is decrease in vessel diameter will increase resistance.

Question 14

Fluid Viscosity

Answer 14

5x thicker than water.

Higher the viscosity, decrease in blood flow, with everything else being equal. We have to increase blood pressure to get blood through there.

Question 15

Turbulence

Answer 15

disruption in laminar flow. Turbulence is created by bifurcation.

The narrowing, whether by on purpose through vasoconstriction, or not on purpose because we’ve got a plaque in that region. Also turbulence creates sound. Turbulence creates edis and swirls.

Question 16

Laminar Flow

Answer 16

straight flow; fastest in the center and slower in the perimeter.

Why is it slower? Because of friction. The immoveable wall causes the drag, they will cause the next layer in to be affected and so on.

Question 17

Systolic Pressure

Answer 17

the peak pressure during ventricular systole

120

Question 18

Diastolic Pressure

Answer 18

the minimum blood pressure during ventricular diastole

80

Question 19

Pulse

Answer 19

the expansion and recoil of an artery as the systolic (pulse) wave passes through it.

Pulse wave is from the ventricular systole.

Question 20

Total Peripheral Resistance

Answer 20

resistance of the entire circulatory system.

Question 21

Peripheral Resistance

Answer 21

resistance in arterial system

Question 22

Blood Volume Effects on Blood Pressure

Answer 22

1) Increase in blood volume will increase blood pressure. Arteries don’t change much in diameter. Veins do. Veins are our blood volume reservoir, which means they will dramatically vasodilate and vasoconstrict to accommodate in increases and decreases in blood fluid volume to maintain blood pressure. We have to maintain blood pressure. Blood pressure shouldn’t change. Part of homeostasis.
2) Decrease in blood volume should equal a decrease in blood pressure. But the vessels would constrict, if the blood volume decreases, to help maintain blood pressure.

Question 23

Neural Regulation of Arterial Pressure

Answer 23

Factors that influence arterial pressure to maintain homeostasis (4 Factors)

1. Vasomotor Center
2. Baroreceptors
3. Chemoreceptors
4. Autonomic NS Control

Question 24

Vasomotor Center

Answer 24

Clusters on neurons in the medulla that control vessel diameter. Cardiovascular and Respiratory systems are integrally linked.

	a) Stimulatory VMC – causes vasoconstriction
	b) Inhibitory VMC – causes vasodilation

Question 25

Basoreceptors

Answer 25

baro means pressure. Responds to alterations in blood pressure. They’re sending their information to those vasomotor centers.

	a) Aortic Baroreceptor - nerves that wrap around the aorta, tell the brain stem whether there’s an increase or decrease in blood pressure. They are the eyes and ears of the vasomotor center, tell them what’s going on. 
	b) Carotid Sinus Baroreceptor - beginning of the internal carotid artery. Can see in humans but not the cats. Monitor the pressure in the carotid artery.  
	c) Atrial Baroreceptor - pressure receptors located in the Atria.

Question 26

Chemoreceptors

Answer 26

sensitive to chemicals in the blood. Refer to the oxygen, CO2, and pH of the blood. Release of ACH.

	a) Aortic Body - travels the same nerves that we see in the baro receptors.
	b) Carotid Body - bifurcation of the internal and external carotids.  It picks up the Oxygen, CO2, and the pH, the chemicals.

Question 27

Autonomic NS Control

Answer 27

a) Sympathetic Stimulation- release of Epinephrine and Norepinephrine acts on these centers, the autonomic nerve centers on the brain stem. Involved in increasing cardiac output through heart rate and force of contraction. Vasoconstriction to the gut and higher centers of the brain. And vasodilation to the extremities and lower brain centers.
b) Parasympathetic Stimulation – decrease in cardiac output, vasodilation to the gut and higher centers of the brain. Vasoconstriction to the extremities and lower centers of the brain.

Release of ACH