Part 6??

Question 1

systole of ventricles

Answer 1

blood leaves heart

Question 2

diastole of ventricles

Answer 2

blood arriving at the heart

Question 3

blood pressure

Answer 3

amount of force applied to a given area of blood vessel wall as the blood flows past it

Question 4

how is blood pressure measured?

Answer 4

a sphygmomanometer measures force acting on the wall. Pressure = force/area.

• smooth muscle in walls is a reflex that contracts when blood comes out of heart (artery stretches for more volume of blood), it maintains the pressure by allowing it to stretch to a limit

Question 5

measuring blood vessel pressure

Answer 5

• measure the force of the blood against the vessels
• measured using sphygmomanometer
• brachial artery is the one that the cuff measures

Question 6

measuring blood pressure

Answer 6

1. cuts off blood supply, (closes vessel),
2. they then listen until the sounds start up again (after reaching max), this is systolic pressure,
3. the diastolic pressure is when the sounds go away again
   - To reach the maximum, blood has to squeeze enough (on the pump that adds air to the cuff) so that artery is closed

Question 7

blood pressure around body

Answer 7

• there are fluctuations on the blood flow which shows contractions and relaxations of heart (pressure is lower during diastole)
• smooth muscle cells help maintain pressure in arteries

Question 8

why does pressure decrease as blood goes from arteries to arterioles etc.?

Answer 8

• friction (more friction the further the blood travels)
• gravity (for the head)
• area (cross-sectional area increases as vessel gets smaller. There are more walls= more friction, increase in cross sectional area will decrease pressure)

Question 9

blood movement to legs

Answer 9

inside the muscle layers of your legs, there are the largest veins. The contraction of the muscles squeeze the veins, the pressure increases and it moves the blood back to your heart

• valves prevent blood from moving down with gravity
• gravity helps move blood from head down to heart

Question 10

pressure and types of veins

Answer 10

veins have lower F, lower pressure and low velocity of blood. Capillaries have high area so low pressure and velocity which is good for diffusion

Question 11

precapillary sphincters

Answer 11

these cut off capillaries so that certain tissues can get more blood when performing an action. during thermoregulation (to avoid heat loss) precapillary things contract and AV shunts relax. When you sweat, skin turns red to allow heat to disappate