Unit Two Cardiovascular System Flashcards
(102 cards)
Explain why we need a circulatory system
Because humans have large surface areas
It provides at least five major functions that are essential to life
What is the function of the arteries, veins and capillaries
Blood circulated from the heart through the arteries to the capillaries, then to the vein before returning back to the heart it’s blood moved away from the heart,
Why is it important that the blood pressure is higher in the capillaries than on the tissue
Allows for pressure filtration
Describe connective tissue
For support and to bind other tissues together
Contains elastic fibres
Describe smooth muscles
Regulated blood flow by contracting and relaxing
Thinner layer than arteries
Describe endotheliums
A thin membrane that lines the inside of the heart and blood vessels
Why is it important that the walls of the arteries are elastic
To accommodate the surge of blood after each contraction of the heart
Explain the terms vasodilation and Vasoconstriction and describe how this occurs
-contractions the diameter of central lumen decreases this decreases blood flow
Relax causing vasodilation. The diameter of the central lumen increases and this increases blood flow
Explain importance of vasodilation and vasoconstriction to blood flow
Contract causing vasoconstriction- reduce blood flow to extremities can reduce heat loss, divert blood flow to muscles
Relax causing vasodilation. Redirect blood to extremities or where blood is needed
What is the function of capillaries
Allow exchange of substances carried in the blood with the body tissues
Describe endothelium
Wider central lumen than arteries
Describe valves
Stops the back flow of blood
What is tissue fluid
A watery fluid that is around cells. And contains essential substances for life
How does oxygen get into tissue fluid
Diffusion
What substances is delivered to tissue
Water
Nutrients
White blood cells
WWN
What substances are taken away from the tissue
CO2
How is the osmotic pressure of blood maintained
Most of the tissue fluid returns to the blood
Explain the movement of fluid
Blood goes in
Tissue fluid comes out
Tissue fluid comes back in
List the substances contained in the returning tissue fluid
Co2
Metabolic waste
Water
99% of tissue fluid returns to the blood. What happens to the other 1%
Becomes lymph
What is the function of the heart
To pump blood around the body to supply oxygen and nutrients to cells and to remove waste products
Where does the left ventricle pump blood
To the whole body
Where does the right ventricle pump blood
Deoxygenated blood to the lungs via the pulmonary artery
Define heart rate
No. Of beats per minute