mass transport in humans Flashcards
what system is the heart
double circulatory system
what is the function of the heart
pump blood around the body
what is pulmonary circulation
blood passes through the heart and is pumped to the lungs, returning back to the heart
what is systematic circulation
The blood now passes through the heart a second time and pumped round the body organs before returning to the heart
Heart structure
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
mass flow
bulk movement of liquids and gasses due to a pressure difference
Mass flow system
- atrial diastole has low pressure and low initial volume
- atrial systole causes an increase in pressure pressure in atrium>ventricle
so AV valve opens - ventricular systole
pressure in ventricle>atrium
so AV valve closes
so SL valve opens - blood > aorta OR
blood > pulmonary artery
ventricular diastole
pressure in ventricle decreases
pressure arteries>ventricles
so SL valve closes
Cardiac Output definition
Cardiac output (dm3min-1)=
Stroke volume x Heart rate
Risk factors in Coronary Heart disease
-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
Heart
-made of cardiac muscle
-pumps blood around the body
coronary arteries
-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
Endothelial layer
-layer is only one cell thick
-smooth layer which reduces friction
-more smooth flow
Elastic layer
-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
Muscle layer
-contracts to restrict the vessel
-reduce the volume of blood flow
-increase blood pressure
outer layer
-fibrous proteins
-gives strength and support to the wall
-to resist damage due to high pressure of the blood
arterioles
-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
capillary
-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
veins
-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
veins
-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
Adaptations of capillaries
-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
Tissue fluid formation
-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
