Cardiovascular System Flashcards
What does the cardiovascular system do?
Circulate and transport nutrients, oxygen, carbon dioxide, hormones and blood cells to and from the cells of the body
Fights disease, stabilises temperature, ph and helps maintain homeostasis
What are the three essential components of the cardiovascular system?
Heart, blood and blood vessels
What is the pulmonary circulation?
a loop through the lungs where blood is oxygenated
What is the systemic circulation?
a loop through the rest of the body to provide oxygenated blood and receive deoxygenated blood
What is a closed circulatory system?
Blood never leaves the vessels
How much blood does an average adult have?
5 litres
How many litres of blood is red blood cells and plasma?
Red blood cells- 2 litres
Plasma- 3 litres
Where is most of your blood at any given time?
Veins
What is bridging?
compression of a segment of coronary artery during systole, causing narrowing that reverses during diastole
What is an end artery?
Terminal artery supplying all or most of the blood to a body part without significant collateral circulation
e.g. coronary artery, splenic artery, cerebral arteries and renal arteries and absolute- retina
What is collateral circulation?
branches of artery are used to supply blood
What occurs in systole?
Left ventricle contraction causes the blood pressure in the aorta to rise and the walls if the elastic arts stretch
What occurs in diastole?
Aortic semi-lunar valves close, and the walls of the aorta recoil, maintaining pressure in the blood and moving it towards the heart and smaller vessels, aortic pressure drops
What do elastic arteries act as?
pressure reservoirs
What are the three layers of an artery and vein wall?
Tunica intima (inside), tunica media, tunica adventitia (outside)
What is an Aneurysm?
A dilation of a blood vessel
What is the tunica intima made out of?
Endothelium
What is the tunica media made out of?
Smooth muscle
What s the Tunica adventitia made out of?
Fibroelastin connective tissue
What are arterioles?
Arteries with a diameter of less than 0.1mm
What are Metarterioles?
Artie that supply blood to capillary beds
What is a precapillary sphincter?
Allow the articles and metarterioles to serve as flow regulators for the capillary bed
If precapillary sphincters are open what occurs?
plentiful blood flow through the capillary bed
What occurs to arterioles during exercise?
Blood flow to skeletal muscle is increased by dilation of arterioles and blood flow to intestine is decreased by constriction of arterioles
How much of our total blood volume do capillaries hold?
5%
What happens in capillaries?
Gas and nutrient exchange
What is a capillary made from?
single layer of endothelium and basement membrane
What is a pericyte?
Form a branching network on the outer surface of the endothelium, can differentiate into muscle cells and fibroblasts
What is a post capillary venule?
receive blood from capillary- more permeable, fluid drains into them due to low pressure
What is a valve?
A venule made of thin extensions
What are the characteristics of a vein?
large diameter, thin wall, more connective tissue, fewer elastic and muscle fibres
What is capacitance?
Ability of blood vessel to increase the volume of blood it holds without a large increase in pressure
How does blood get from the legs to the heart?
muscle contraction, thoracic pump causes negative pressure when breath in and out from diaphragm, valve prevents backflow
What does calf muscle pump failure lead to?
Venous hypertension
What does gravity cause for the body?
vertical gradient of Venous pressure
