mass transport in humans

Question 1

what system is the heart

Answer 1

double circulatory system

Question 2

what is the function of the heart

Answer 2

pump blood around the body

Question 3

what is pulmonary circulation

Answer 3

blood passes through the heart and is pumped to the lungs, returning back to the heart

Question 4

what is systematic circulation

Answer 4

The blood now passes through the heart a second time and pumped round the body organs before returning to the heart

Question 5

Heart structure

Answer 5

1.deoxy-blood from body > vena cava > right atrium
2.right atrium > atrioventricular valve > right ventricle
3.right ventricle > semi-lunar valve > pulmonary artery
4.pulmonary artery > lungs > pulmonary vein> left atrium
5.left atrium > atrioventricular valve > left ventricle
6.left ventricle > semi lunar valve > aorta > body

Question 6

mass flow

Answer 6

bulk movement of liquids and gasses due to a pressure difference

Question 7

Mass flow system

Answer 7

1. atrial diastole has low pressure and low initial volume
2. atrial systole causes an increase in pressure pressure in atrium>ventricle
   so AV valve opens
3. ventricular systole
   pressure in ventricle>atrium
   so AV valve closes
   so SL valve opens
4. blood > aorta OR
   blood > pulmonary artery
   ventricular diastole
   pressure in ventricle decreases
   pressure arteries>ventricles
   so SL valve closes

Question 8

Cardiac Output definition

Answer 8

Cardiac output (dm3min-1)=
Stroke volume x Heart rate

Question 9

Risk factors in Coronary Heart disease

Answer 9

-high cholesterol diet
-high lipid diet
-lack of exercise
-smoking

CAUSES
-high blood pressure
-increase blood toxins
-increase level of cholesterol in blood

LEADS TO
-damage to endothelium wall
-increase in lipid uptake

Question 10

Heart

Answer 10

-made of cardiac muscle
-pumps blood around the body

Question 11

coronary arteries

Answer 11

-branches off the aorta to take blood to the muscle of the heart
-heart muscle needs its ow capillary supply for rapid delivery of oxygen

Question 12

Endothelial layer

Answer 12

-layer is only one cell thick
-smooth layer which reduces friction
-more smooth flow

Question 13

Elastic layer

Answer 13

-elastic protein fibres
-walls stretch to allow blood to flow so pressure isn’t too high
-recoils when blood passes
-maintains the hydrostatic pressure on the blood

Question 14

Muscle layer

Answer 14

-contracts to restrict the vessel
-reduce the volume of blood flow
-increase blood pressure

Question 15

outer layer

Answer 15

-fibrous proteins
-gives strength and support to the wall
-to resist damage due to high pressure of the blood

Question 16

arterioles

Answer 16

-smaller vessels than arteries that connect the artery to the capillaries
-more friction for blood
-decrease in blood pressure
-elastic layer is thinner as blood pressure is lower
-muscle layer is thicker to restrict/open the vessel to increase/decrease blood flow to the organ

Question 17

capillary

Answer 17

-walls only have endothelial layer
-involved in the exchange in materials from the blood to the respiring cells
-diameter is very small to increase friction
-decrease blood pressure and blood flow

Question 18

veins

Answer 18

-blood vessels that carry blood back to the heart
-blood is under lower pressure so the wall doesn’t need to be thick
-muscle layer is thinner as all blood is going back to the heart
-elastic layer is thin as pressure is low and the walls do not need to stretch and recoil
-veins have valves so no back flow
-veins have skeletal muscles that contract and squeeze the vein forcing the blood up

Question 18

veins

Answer 18

-blood vessels that carry blood back to the heart
-blood is under lower pressure so the wall doesn’t need to be thick
-muscle layer is thinner as all blood is going back to the heart
-elastic layer is thin as pressure is low and the walls do not need to stretch and recoil
-veins have valves so no back flow
-veins have skeletal muscles that contract and squeeze the vein forcing the blood up

Question 19

Adaptations of capillaries

Answer 19

-thin walls SO decrease the diffusion distance
-numerous and branched SO increases the surface area
-narrow diameter SO red blood cells is in contact with the walls
-fenestrations SO rapid rapid formation of tissue fluid and WBC to pass through

Question 20

Tissue fluid formation

Answer 20

-materials pass from the plasma > tissue fluid > cells
-hydrostatic pressure and water potential differences affect the movement of fluid into and out the capillary
-HP in blood is > than the HP in the tissue fluid SO a net force pushes the fluid/water out the capillary fenestration ( ULTRAFILTRATION)
-The WP in the tissue fluid > the WP in the blood
-this creates a WP gradient to allow water to return to the capillary via osmosis
-blood has a higher HP causing a greater force pushing out then pulling in due to the WP difference
-water leaves the capillary forming tissue fluid
-large proteins stay in the capillary so WP in the capillary decreases
-now WP force pulling in is higher than HP force pushing out
-water re-enters the capillary
-excess water is removed from the tissues via the lymph vessels