Ianowski - theme 13 and 14 Flashcards
With condom vs without condom - pressure:
Pressure fluctuates high without condom. Condom keeps pressure fairly consistent.
If the condom hardens:
Systolic pressure rises and hypertension results
Max systolic pressure in humans:
120 mmHg
Minimum diastolic pressure in humans:
80 mmHg
Mean arterial pressure equation: (2)
MAP = diastolic pressure + (difference between systolic and diastolic)
MAP = cardiac output * total peripheral resistance
Effect of cardiac output on MAP:
Positive linear relationship!
Effect of arteriole diameter change on MAP:
Smaller diameter = higher peripheral resistance = higher pressure = higher MAP
Cardiac output equation:
Cardiac Output (mL/min) = heart rate (beats/min) * stroke volume (mL/beat)
Poiseuille’s law:
Q (blood flow, also cardiac output?**) = delta P / R
P is pressure.
R is resistance. R = 8ηL/πr^4
Which cells are pacemaker cells?
SA node cells
What is the most important factor for determining flow resistance?
Arteriole radius
Parasympathetic effect on cardiac output:
Slows heart rate.
Sympathetic effect on cardiac output:
Increases heart rate and stroke volume. Increases tone of veins to increase venous return, raising end diastolic volume, raising stroke volume.
Mammalian veins contain what % of total blood volume?
Over 60%
What determines the amount of blood flow that goes to an organ?
Number and diameter of arterioles
Local (intrinsic) changes to arteriole diameter:
Local metabolic changes, histamine, temperature, stretch receptors
Extrinsic control of arteriole diameter:
Sympathetic stimulation redirects blood away from nonessential organs to heart and skeletal muscles. NE or epinephrine activate alpha-1 receptors in most tissues to cause vasoconstriction. Lungs and brain do not have alpha-1 receptors. Epinephrine activates beta-2 receptors in heart and skeletal muscles and cause vasodilation.
The gigantic story of renin and angiotensin:
Kidney stimulated by symp NS, hypotension, or decreased sodium delivery. Secretes renin. Renin breaks angiotensinogen into A1. A1 is broken down into A2 by ACE. Then A2 does everything.
Effects of angiotensin II:
Cardiac and vascular hypertrophy.
Systemic vasoconstriction to raise arterial pressure.
Thirst and renal retention of sodium and fluids to increase blood volume to increase cardiac output to increase arterial pressure.
Increased aldosterone production from adrenal cortex to increase renal retention again.
Response to hemorrhage:
Trying to keep the brain oxygenated. Bunch of stuff happens to lower arterial pressure, which causes symp to increase heart rate and contractility, resistance, and venous tone. You bleed to death real fast.
Also, hormonal. I think the takehome message is that there are a bunch of ways of controlling arterial pressure. ***
