Introduction to the CVS Flashcards
Describe the breakdown of the word cardiovascular
cardio= heart
Vasculature = blood vessels
Why do we need a CVS?
The roles of the CVS is:
1) Pump blood through lungs and carry oxygen
2) Temperature regulation
3) Human reproduction
4) Connection to lymphatic system
5) Circulates hormones and immune mediators
6) Transport nutrients and muscles and organs
What is the definition of passive diffusion?
Passive diffusion is the random undirected thermal movement of molecules
What is a disadvantage of passive diffusion?
Diffusion is fast over a small distance, however as distance increases, the time taken for diffusion to occur also increases.
What is the relationship between the time and distance
The time needed to diffuse a given distance is proportional to the square of the distance.
Explain blood flow through the right side of the heart
Blood returns to the heart from the veins via the right atrium.
The blood is then pumped through the lungs via the right ventricle
Explain blood flow through the left side of the heart
Blood returns to the heart from the lungs via the left atrium.
Blood is then pumped through the body via the left ventricle
What is typical resting blood pressure
120/80 Mhhmm is typical blood resting pressure
What is the definition of systole and diastole
systole= contraction
Diastole= relaxation
What is the equation of cardiac output?
cardiac output= heart rate x stroke volume
What is the equation for maximum heart rate
maximum heart rate= 220 - Age
What controls blood flow and determines blood pressure?
Blood flow is:
1) Proportional to pressure across blood vessel
2) Inversely proportional to resistance of blood vessel
What is the equation for blood flow
blood flow= (Pa - Pv)/ Resistance
Pa= Pressure of artery
Pv= Pressure of vein
What are the 4 main functional groups of blood vessels?
4 main functional groups:
-Arterioles
-Arteries
-Venules and veins
-Capillaries
What are the functions of these blood vessels?
Arterioles - control arterial BP and regulate local blood flow
Arteries- Accommodate stroke volume convert ejection into continuous flow
Capillaries- Nutrient delivery to cells tissue water and lymph formation
Venules and veins- control filling pressure of the heart and provide a reservoir of blood.
Where does the cardiac output and oxygen consumption go at rest
Cardiac output at rest goes to:
-mainly to the liver and GI tract (25%)
-then the kidneys and muscle (20%)
-other (18%)
Oxygen consumption at rest goes to:
-liver and GI tract (30%)
-muscle (20%)
-brain (18%)
How do Arterioles control arterial BP
Arterioles are resistance vessels and control BP by determining total peripheral resistance
How is the velocity in the capillaries
Velocity is much slower in capillaries allowing gaseous/nutrient exchange to occur
Describe the distribution of blood volume in blood vessels, lungs and heart
-Large veins and venous networks (40%)
-Small veins and Venules (25%)
-Heart, Lungs and Arteries (10%)
-Capillaries (5%)
How do sympathetic nerves cause vasoconstriction in blood vessels
Sympathetic nerves in the tunica adventitia release noradrenaline which stimulates a1 receptors leading to vasoconstriction.
How does the endothelium cause vasodilation in the blood vessels
Endothelium releases nitric oxide which relaxes the vessels leading to vasodilation
What is the purpose of tunica intima in the endothelial layer
The purpose of the tunica intima in the endothelial layer, this controls the vascular permeability and modulates vasoconstriction .
What is the purpose of the tunica media in the smooth muscle
the tunica media in the smooth muscle is embedded in an extracellular matrix and regulates vasoconstriction and vasodilation of vessels
What is the tunica adventitia in the collagenous material
The tunica adventitia are fibroblasts in an innervated layer.
