8.2 Blood Vessels Flashcards
What is the role of collagen?
- Fibrous proteins provide mechanical strength
- collagen helps to withstand the high pressure, therefore preventing these blood vessels from bursting.
What are the 3 tunica layers in the artery?
- Tunica intima
- Tunica media
- Tunica externa
What does the narrow lumen does ?
- maintains the high blood pressure of the blood that flows through this vessel.
Suggest 2 changes that will be made to the blood by the arterioles and explain why these changes are necessary?
- From the arteries to arterioles there is a decrease in blood pressure = less volume
What are the types of blood vessels ?
Arteries , arterioles , capillaries, venues , veins
What do arteries have and do?
- Carry blood AWAY from heart to the rest of the body
- thick walls and muscular
- elastic issue to stretch and recoil = maintains high blood pressure
- inner lining (endothelium ) is folded = artery expand , also maintains high blood pressure .
What s the role of the smooth muscle in the arteries?
- reduces the lumen.
- the SM can be innervated to contract
- increases resistance and reduces the rate of blood flow .
- this allows the blood to be diverted away from some areas and towards other areas where the demand for oxygen is greater.
What do veins do and have?
- Take blood IN the heart
- under low pressure
- Wider lumen with a very little elastic or muscle tissue.
- They contain valves = to stop the blood flowing backwards.
Describe how the features of the capillaries increase the rate of movement of oxygen out of theses blood vessels. (3)
- thin wall / diffusion distance
- the lumen is narrow so squeezes the red blood cell as they flow a long the capillary.
What is the oncotic pressure?
- pressure created by the osmotic effects of the solutes in a solution
- also measured in kPa and like water potential.
Suggest why the hydrostatic pressure of the blood decreases as it moves from the arterioles to the venule
- Small molecules , including water are forced out of the capillary at the arteriole end due to the high hydrostatic pressure
- causes the volume of the fluid to decrease and therefore the hydrostatic pressure decreases.
What is a tissue fluid?
Is the fluid that surrounds cells tissues
Where does the excess tissue fluid go ?
- The tissue fluid drains into the lymph vessels
What is the process of the lymphatic system?
- the excess tissue fluid passes into lymph vessels . Once inside is called the lymph .
- Valves in the lymph stops the lymph from going backwards .
- Gradually the lymph moves towards the main lymph vessels in the thorax
- here is returned to the blood , near the heart .
