Cardiovascular System Part 1 W5 Flashcards
What does the heart do?
Creates pressure to pump blood
What are the 3 purposes of the cardiorespiratory system?
Transport O2 and nutrients to tissues
Removal of CO2 wastes from tissues
Regulation of body temperature
What are the 2 major adjustments of blood flow during exercise does the cardiovascular system do?
Increased cardiac output
Redistribution of blood flow form inactive organs to active muscle
What do arteries do?
Carry blood away from the heart
What do capillaries do?
Exchange of O2, CO2 and nutrients with tissues
What do veins do?
Carry blood toward the heart
What is the pulmonary circuit?
Right side of the heart
Pumps deoxygenated blood to the lungs via pulmonary arteries
Returns oxygenated blood to the left side of the heart via pulmonary veins
What is the systemic circuit?
Left side of the heart
Pumps oxygenated blood to the whole body via arteries
Returns deoxygenated blood to the right side of the heart via veins
What is haematocrit?
Percentage of blood composed of erythrocytes
What is blood plasma?
Contains ions, proteins and hormones
It is the liquid portion of blood
What cells are found in blood?
Red blood cells (erythrocytes)
White blood cells
Platelets
What cells are important in blood clotting?
Platelets
White blood cells
What do red blood cells do?
Contain haemoglobin to carry oxygen
What is normally the common value of haematocrit?
42%
What is the main resistance to blood flow?
Arteries and Arterioles
Where is pressure generated?
In the heart (left ventricle)
What is mean arterial pressure?
100mmHg
What is resistance?
A measure of hindrance or opposition to blood flow through a vessel, caused by friction between the blood in the vessel wall
What is total peripheral resistance?
Sum of resistance to slow in all individual organs
What is blood flow relationship with pressure?
Directly proportional to the pressure difference between the 2 ends of the system
What is blood flow relationship with resistance?
Inversely proportional
What are pressure relationships?
Proportional to the difference between MAP and right atrial pressure
What is resistance dependent on?
Length of vessel
Viscosity of the blood
Radius of the vessel
What is Darcy’s Law?
Blood flow= pressure divided by resistance
What has the greatest influence on resistance?
Radius of the vessel
What is low vascular resistance?
The resistance to blood flow in an organ or tissue calculated from pressure and local/organ tissue flow
What is resistance equation?
Resistance= (length x viscosity) divided by radius
What is Poiseuille’s law?
Resistance is inversely proportional to radius in a single vessel
What is arteriovenous difference?
Amount of O2 that is taken up from 100ml of blood
Increases during exercise due to increase in O2 uptake in tissues
How is total peripheral resistance calculated?
When MAP and CO are known
(MAP= CO x TPR)
How is oxygen consumption calculated?
Oxygen consumption= cardiac output x A-V oxygen difference
What is Fick equation?
Relationship between:
Cardiac output,
a-VO2 difference
VO2
What are baroreceptors sensitive to?
Sensitive to changes in arterial blood pressure
What are muscle mechanoreceptors sensitive to?
Sensitive to force and speed of muscular movement
What are muscle chemoreceptors sensitive to?
Sensitive to changes in chemical environment (H+ ions, CO2, changes in pH)
What is he exercise pressor reflex?
Peripheral feedback tot he medulla oblongata to amend the CV response
What plays an active role in resetting the arterial baroreflex during exercise?
Central command
Exercise pressor reflex
Why is there an increase in systolic blood pressure during exercise?
Due to the baroreflex being reset during exercise
