heart and blood vessels

Question 1

why does the left ventricle have thicker more muscular walls than the right ventricle

Answer 1

it allows it to contract more powerfully and pump blood all the way around the body

Question 2

what is the function of the cords

Answer 2

they attach the atrioventricular valves to the ventricles to stop them being forced into the atria when the ventricles contract

Question 3

what is the function of the semi lunar valve

Answer 3

stop blood flowing back into the heart after ventricles contract

Question 4

what is the function of the atrioventricular valves

Answer 4

stop blood flowing back into the atria when the ventricles contract

Question 5

what is the function of the veins

Answer 5

to take blood back into the heart under low pressure

Question 6

what is the function of the arterioles

Answer 6

they control the direction of blood flow
contract to restrict blood flow
relax to allow full blood flow

Question 7

what is the function of the arteries

Answer 7

they carry blood away from the heart at high pressures

Question 8

what is the function of the capillaries

Answer 8

gas exchange (diffusion of oxygen into RBCs)

Question 9

what are the walls of the arteries like

Answer 9

thick and muscular walls
lots of muscular tissue
lots of elastic tissue

Question 10

what is the function of the elastic tissue in the walls of the artieres

Answer 10

it allows it to strech and recoil as the heart beats to maintain pressure

Question 11

what is the function of the muscular tissue in the arteries

Answer 11

it allows it to withstand high pressures

Question 12

how are cappillaries adapted for gas exchange

Answer 12

their walls are thin-short diffusion distance

there are large numbers of cappliaries which increases surface area for gas exchange

Question 13

how are veins adapted for their function

Answer 13

relatively large lumen
valves
surrounded by body muscles

Question 14

describe how tissue fluid is formed

Answer 14

start of cappilary bed near arteries 
hydrostatic pressure greater 
than in tissue fluid 
difference in hydrostatic pressure 
means overall outward pressure 
forces fluid out of the cappillaries into spaces 
around cells forming tissue fluid

Question 15

what happens to the pressure in the cappillary as fluid leaves the cappillary

Answer 15

it decreases
so hydrostatic pressure
much lower at venule end of cappillary

Question 16

why is the water potential in the venule end of the cappillary bed lower than in the tissue fluid

Answer 16

due to:
fluid loss
increasing concentration of blood protein

Question 17

what does water do at the venule end of the cappillary

Answer 17

it re-enters the cappillary bed by osmosis

Question 18

what happens to the excess tissue fluid

Answer 18

it is drained into the lymphatic system
which transports excess fluid from tissues
passes it back into circulatory system