Cardiovascular and lymphatic systems Flashcards
*Why do veins not need to have thick walls?
As there is very low pressure
*What is the vein like in comparison to arteries?
Same 3 layers, but the middle coat contains far fewer elastic of smooth muscle fibres.
*What is an advantage of the endothelium being smooth in the artery?
To reduce friction between blood and blood vessel wall.
*An advantage of the endothelium being smooth in the artery?
Allows them to stretch as the high pressure blood is pumped out of the heart. This makes the artery wider and reduces the pressure.
*What do the semi lunar valves in the veins do?
Open to allow blood to flow towards the heart and close to stop it falling back down.
*What is mass flow?
the bulk movement of substances from one area to another due to differences in pressure.
*What are some substances transported in the blood?
glucose, hormones.
*What do arteries do?
Carry blood away from the heart. they branch off to form smaller vessels called arterioles
*Which artery does blood from the right side go into?
pulmonary artery (then to the lungs)
*Which artery does blood from the left side go into?
aorta (then to the rest of the body)
*What does blood plasma transport?
-CO2 from organs to the lungs
-soluble products of digestion from the small intestine to other organs.
-urea from the liver to the kidneys
*What is the spleen?
A storage organ for leucocytes and antibodies used to fight some pathogens produced here. Also stores erythrocytes and some thrombocytes in case of emergency.
*What are lymph vessels?
blind ended and contain valves, no internal pump, so lymph only moves through vessels surrounding skeletal muscle.
*What is lymph fluid?
made up of remaining tissue fluid, water, small proteins, some nutrients and lymphocytes.
*What are lymph nodes?
Are sac like specialised lymph tissues that collect lymph from several vessels and filter it. contain many leucocytes to help fight any pathogens that try to enter the body.
*What is tissue fluid used for?
-essential for the efficient exchange of materials between the blood and the cells.
-The cells of the body are bathed in the tissue fluid, which provides them with water, oxygen, glucose and other nutrients
*Why is the wall of an artery thick?
To withstand the high pressure of blood.
*label the diagram of an artery
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*Why do some plasma proteins not leave the capillary along with the fluid?
They are too large to fit through the pores in the capillary walls.
*Why is tissue fluid formed?
As at the arteriole end, the blood pressure is greater than the water concentration gradient. As a results water and solutes are forced out of the blood through the pores in the capillary walls.
*At the arteriole end of the capillary the hydrostatic pressure of the blood is high. What causes this?
The concentration of the left ventricle in the ventricular systole
*What does the high blood pressure force out?
water, salts and nutrients.
*What does the soluble plasma proteins in the blood do?
They reduce the water concentration of the blood which creates a water concentration gradient.
*How are capillaries suited to their function?
-pores in walls to increase permeability
-small size and a large number of capillaries to give a large surface area
-narrow diameter-slows blood flow, so more time for diffusion/exchange.
*Label the capillary
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*What do capillaries exchange?
Nutrients and dissolved gases with the tissue fluid which bathes all of the body’s cells.