Topic 1: Blood pressure Flashcards
Define blood pressure
1 point
The HYDROSTATIC (due to water) FORCE that blood exerts against the wall of a blood vessel.
- What equipment do you use to measure blood pressure? (1 equipment)
- What are the units?
- How is the equipment used? (2 steps)
- Sphygmomanometer
- mmHg
- (1) Inflate cuff around arm to stop blood flow, (2) then release the pressure slowly until blood flow starts again
Define systolic blood pressure (1 point) + give systolic range (with units)
- pressure in the arteries {when the ventricles contract/ in systole}
Systolic ‘range’ = 100-140 mmHg
Define diastolic blood pressure (1 point) + give diastolic range (with units)
- pressure in the arteries {when the heart relaxes/in diastole}
Diastolic ‘range’ = 60–90 mmHg
- What does tissue fluid surround? (1 thing)
- Surrounds cells.
Tissue fluid is formed from _______ _______, ________ forces fluid through ______ in capillary walls.
What is tissue fluid similar to? (1 point)
blood plasma
pressure
pores
- So tissue fluid is SIMILAR IN COMPOSITION TO PLASMA, but with no blood cells and large proteins.
__________ + nutrients diffuse from tissue fluid into _______
____________ __________ + waste diffuse from ______ to _________ _______
_________ _______ is reabsorbed into _________
oxygen
cells
carbon dioxide
cells
tissue fluid
tissue fluid
blood
Explain how tissue fluid is formed and reabsorbed.
8 steps
- The formation of tissue fluid is a balance between TWO pressures.
- HYDROSTATIC (blood) PRESSURE tends to force fluid out of a capillary.
- THE OSMOTIC (tissue fluid) PRESSURE tends to move water into the capillary, due to the high solute concentration of the blood.
- At the ARTERIOLE end of the capillary the BLOOD PRESSURE IS HIGHER than the osmotic (tissue fluid) pressure.
- There is a NET MOVEMENT of fluid OUT of the capillary into the area surrounding the cells.
- The blood pressure in the capillary then decreases, due to resistance and fluid being lost.
- At the VENULE end of the capillary the OSMOTIC PRESSURE IS NOW HIGHER than the hydrostatic pressure.
- There is a NET MOVEMENT of fluid BACK INTO the capillary.
NOTE: Arteriole end are capillaries closer to the arteries (which form from arteries), Venule end are capillaries closer to the veins (which eventually form veins)
The blood pressure at the arteriole end of a capillary bed is 9.5 kPa and the blood pressure at the venule end is 1.5 kPa.
Calculate the percentage decrease in the blood pressure.
Data = 9.5 and 1.5 kPa
Difference = 9.5 - 1.5 = 8.0 kPa
Divide by the starting point = (8.0 / 9.5) x 100% = 84.2%
What is oedema? (1 point)
- oedema is fluid build-up in tissues which causes swelling.
What is oedema a sign of? (1 point)
- Oedema is a sign of high blood pressure
Note:
oedema can also be associated with kidney or liver disease, or arise from restricted movement
How does high blood pressure cause oedema? (1 point)
- High blood pressure forces {more/too much} fluid from the blood plasma through the capillary walls into the tissue fluid (fluid which surrounds cells)
What is considered high blood pressure (in mmHg)? (1 point)
- above 160/95 mmHg
NOTE: blood pressure usually measured with systolic over diastolic
so 160 is systolic, 95 is diastolic
What is the name given to the condition of ‘persistently high blood pressure’? (1 point)
- Hypertension
Why does high blood pressure increase the risk of developing CVD? (2 steps)
- increases the risk of damage to the endothelium of arteries
- which can trigger atherosclerosis and blood clotting
