Physiology 534 Final: Regulation Of Pressure And Volume

Front 1

Controlling circulation

Back 1

Need to keep arterial pressure constant to assure adequate flow.

To regulate arterial pressure, adjust CO and SVR

Front 2

CO is adjusted with what factors?

Back 2

1. Filling of the heart
2. Heart rate
3. contractility

Front 3

SVR is adjusted by means of the?

Back 3

SNS and hormonal control

Front 4

When does central control override local control?

Back 4

1. Regulatlion of body temp: both local & central

2. Muscle blood flow in anticipation of exercse: all central

3. External genitalia: CNS controls overcome local requirements

Front 5

Arterial Baroreceptor Reflex

Back 5

Arterial pressure is sensed by stretch receptors

Front 6

As pressure increases, stretch receptor nerve firing goes to a region in the medulla oblongata

Back 6

The nucleus tractus solitarius(NTS)

Compare current frequency of nerve firing to the "ideal" firing frequency

Front 7

How does the NTS adjust firing rate?

Back 7

SNS and PNS activity to the hert and blood vessels

Front 8

What influcences baroreceptors firing rate?

Back 8

1. Mean arterial pressure (MAP)
2. Pulse pressure

Front 9

The baroreceptor firing rate inc/dec with mean arterialpressure and pulse pressure?

Back 9

Increases

Front 10

What happens with there is an inc. in arterial pressure?

Back 10

inc. in baroreceptor stretch--> inc. in baroreceptor firing rate-->dec. SNS and inc. PNS

Front 11

What happens when we inc. PNS?

Back 11

Inc. M2 receptor activation via Ach--> dec. HR -->dec. contractility and dec. CO

Front 12

What happens when we dec. SNS?

Back 12

Dec. B-receptor activation-->dec. HR-->dec. SV-->dec. CO

Also, dec. alpha-receptor activation-->dec. SVR by relaxing smooth muscle

Front 13

Cardiopulmonary Reflex

Back 13

Atria, ventricles, and pulmonary vessels have stretch receptors.

All of these vessels contain Central blood volume. So this reflex tells us the effect of dec. central blood volume.

Front 14

How does the cardiopulmonary reflex work when there is an dec. in central blood volume?

Back 14

dec. in CBV-->dec. in stretch-->dec. in firing-->inc. SNS and dec. PNS-->inc CO and inc SVR

Front 15

What are the 2 short-term regulators?

Back 15

1. Arterial Baroreceptor Reflex

2. Cardiopulmonary Reflex

Front 16

What 3 mechanims are important for regulation of Na and water?

Back 16

1. Renin-angiotensin aldosterone system

2. Antidiuretic Hormone

3. Natriuretic Peptides

Front 17

Renin-Angiotensin Aldosterone system

Back 17

-Regulates Na

-Releases angiotensin II when inc. SNS and dec. arterial pressure

Front 18

What are the 4 effects of angiotensin II?

Back 18

1. Powerful vasoconstrictor that inc. SVR

2. Promotes thrist

3. Stimulates the release of ADH

4. Promotes the release of aldosterone from the adrenal cortex-->dec. excretion of Na ions

Front 19

Antidiuretic Hormone (ADH or vasopressin)

Back 19

Regulates water by telling the kidney to dec. water excretion

Front 20

ADH is released in response to three stimuli

Back 20

1. Dec. in firing of the stretch receptors when CBV dec.

2. Inc. in plasma osmolarity

3. Angiotensin II

Front 21

Natriuretic Peptides

Back 21

Regulates sodium by promoting the excretion of Na

Front 22

What are the 2 mechansims that control Natriuretic peptide?

Back 22

1. Atrial stretch: releases ANP

2. Ventricular stretch: releases BNP

Front 23

What is the long-term regulation mechanism?

Back 23

Changes in blood volume, which influcene PV and BV-->influences CO and arterial pressure

inc ECF-->inc PV & inc. BV

inc. BV-->inc CBV-->inc. CO-->inc. arterial pressure

Front 24

What is the most powerful long-term regulator?

Back 24

Pressure Diuresis

Inc. arterial pressure-->inc. excretion of sodium and water

Front 25

How does pressure diuresis restore an increase in arterial pressure?

Back 25

Inc. arterial pressure-->inc. excretion of sodium and water-->dec. Na and water in ECF-->dec. BV-->dec CO-->restore arterial pressure

Front 26

What are the 4 mechanisms that will regulate blood volume?

Back 26

1. RAAS: renal saving of Na

2. ADH: renal saving of water

3. ANP and BNP: excretion of Na

4. SNS: direct saving of Na and water

Front 27

What is the cardiovascular response to standing?

Back 27

Shift of blood from the CBV to the PBV-->dec. in ventricular filling (EDV)-->dec. SV-->dec. CO-->dec. Pulse pressure (bc Pp determined by both SV and aortic compliance).

Front 28

How is the mean arterial pressure restored when standing?

Back 28

dec. in stretch receptor firing from both reflex systems-->inc. in firing of SNS and dec. in PNS. --> inc HR and CO, activation of B-adrenergic recptors inc contracitlity--> inc SV

Front 29

Points to remember about standing

Back 29

1. Standing activates both the baroreceptor and cardiopulmonary receptor reflexes

2. A dec. in both pulse pressure and mean arterial pressure activate baroreflex

Front 30

Prolonged standing causes?

Back 30

Pressure exerted on veins-->expand-->trap more blood-->less blood for the CBV-->less ventricular filling

Front 31

What does standing do to the capillary pressure?

Back 31

Increases capillary pressure-->promotes capillary filtration-->dec. plasma volume

Front 32

The Respiratory Pump-taking deep breaths, daiphragm contracts and does 2 thing:

Back 32

1. Dec. intrathroacic pressure-->inc. Ptm-->vessels expand and volum inc.

2. Inc. intrabdominal pressure-->dec. Ptm-->dec. volume of abdominal wall

From here, the blood goes into the chest with inc. venous return and CO

Front 33

The muscle pump

Back 33

Provides increased venous return by contraction of leg muscles

Squeezes on the leg veins so blood flows towards heart (bc of valves)