Lecture 3

Question 1

What is the primary function of circulation?

Answer 1

To provide adequate flow to organs

Question 2

What is MAP?

Answer 2

Mean Arterial Pressure = CO x TPR; changing HR, SV, and TPR = change in MAP
MAP = Diastolic Pressure + 1/3(Pulse Pressure)

Question 3

What happens when organs need more blood?

Answer 3

Organs are the site of TRP. Decrease TPR -> Increase BF to organs.
Dec TPR - Increases PVP - Change in Pressure Gradient - +ve - increase VR - Increase CVP(final) - Increases CO
vs. Initially - MAP decreases due to a decrease in TPR - decrease MAP - body says increase MAP

Question 4

What is Central Venous Pressure?

Answer 4

CVP = The pressure of the Great Thoracic Vessels = RAP = VR

Question 5

Vascular Function Curve

Answer 5

Increase VR with a Decrease in CVP….
Q = P/R
Decreasing CVP - Increased Pressure Gradient; PVP -> CVP - Thus increasing VR

Question 6

How does the body infer adequacy of CO?

Answer 6

BP, yet can also use pH, pO2, PCO2 when BP < 60.

Question 7

What is the baroreflex?

Answer 7

Short term BP regulation; neural control
Baroreceptors located in the carotid arteries, aortic arch, and pre-glomerulus apparatus (renin, the SM convert into granular cells)

Question 8

What is the Baroreceptor/Pathway?

Answer 8

Thin walled (more compliant thus feels the change in pressure easily), highly innervated; sensitive to stretch; increase or decrease stretch - increase or decrease in AP firing - signal to medulla. 
The medulla has depressor (parasympathetic) and pressor (sympathetic) fxn. 
Within one cardiac cycle - a change can be seen

Question 9

What is the sympathetic role in the baroreflex?

Answer 9

Sympathetics innervate:
Heart - 1) Increases Contractility and 2) SA/AV - decreases conduction time at the AV node - thus increasing HR
Vasculature - 1) Increases TPR and 2) VENOconstriction - constriction pushes more blood into the arterial system.

Question 10

What happens if you don’t have a BAROreflex?

Answer 10

Lose smoothening capacity of the BP, variations in BP - wider curve.

Question 11

What happens to the Baroreflex in new environments?

Answer 11

It has the ability to reset itself.

As ppl age, compliance of vessels decrease, increase in sensitivity.

Question 12

What is the distribution of BP?

Answer 12

It is unimodal and right tailed. Males ted to have a higher pressure.
We are always increasing our systolic pressure due to age related stiffness in the vessels, whereas diastolic tends to decrease after 60 years of age - because pulse pressure determined by compliance.

Question 13

Distribution/Changes of BP during development

Answer 13

At birth - males and females similar BP
Puberty - females > males
Adult - Males > Adults

STEEPEST CHANGE IN BP AFTER BIRTH

Question 14

How does the physical body relate to BP?

Answer 14

Changing/Increasing (weight, height, waist, BMI) - increases BP

Question 15

What happens to BP during the night?

Answer 15

Minimal Sympathetic Activation - therefore a drop in BP, But to prevent a big drop the RENIN-ANGIOTENSIN system kicks in.
Drop in about 20 mmHg

Question 16

What happens to BP during the summer?

Answer 16

Decrease in BP due to appearance, the winter we are less active and thus increase weight. Increase weight increases BP

Question 17

Is hypertension a disease?

Answer 17

NO, its just the upper limit of the BP curve.
The hypertension continues to fall as there are better drugs out there - we can use these earlier before the onset of major issues.

Question 18

What is the Population Paradox?

Answer 18

The idea that ppl that don’t have high BP - usually end up dying due to cardiovascular problems. Why? Because ppl with higher BP are put on medications that eventually decreases their BP.