Circulation

Question 1

Capillary exchange

Answer 1

• only in capillaries
• materials leave blood and diffuse into the interstitial fluid then into body cells
• RBC, platelets, and plasma proteins can’t pass through walls of capillaries (impermeable)

Question 2

What affects the net pressure of the capillary?

Answer 2

• BP (hydrostatic pressure): higher at arterial end of capillary, due to pumping action of heart
• Osmotic pressure: mov. of fluid into capillary, due to high con. of plasma proteins. Not affected by the end of the capillary

Question 3

hemorrhage

Answer 3

• vast reduction in blood volume

- net fluid pressure is from the interstitial fluid into the capillaries due to the low BP

Question 4

inflammation/allergic reactions

Answer 4

• “endangered” cells release histamine which changes the permeability of the capillary wall
• plasma proteins and white blood cells can leave the capillary and enter the interstitial fluid due to low osmotic pressure

Question 5

Starvation

Answer 5

• body uses plasma proteins as an energy source

- tissue swelling due to excess fluid movement into the interstitial fluid

Question 6

In veins, movement of blood is dependant on

Answer 6

1. skeletal muscle contraction
2. one way valves preventing backflow of blood
3. vasoconstriction for when BP is low
4. breathing

Question 7

Peripheral Resistance

Answer 7

• restriction of blood flow due to friction (blood sliding along vessel walls)
• more common in large blood vessels and ones further (on periphery) of the heart

Question 8

Peripheral Resistance is affected by what?

Answer 8

1. Vasomotor changes (vasoconstriction increases 
vasodilation decreases) 
2. Elasticity of blood vessels
(less elastic increases PR) 
3. Viscosity of blood 
(dehydration/too many RBC increase PR)
4. Total blood volume

Question 9

BP cuff

Answer 9

• sphygmomanometer
• the instrument used to measure BP
• measures systolic/diastolic (relax) pressure
• measurements given as systolic pressure/diastolic pressure (ex. 120/80)

Question 10

Steps to measuring blood pressure (AILS SRD)

Answer 10

1. apply sphygmomanometer to brachial artery, and inflate w/ air until blood flow is cut off (~160 mmHg)
2. Listen to the point below the sphygmomanometer w/ stethoscope
3. Slowly release pressure on brachial artery
4. first sounds heard – systolic pressure
   (avg. reading is 120 mmHg)
   blood spurts through the artery as pressure on arm=systolic pressure
5. continue to slowly release pressure on brachial artery
6. sounds become muffled and disappear—diastolic pressure
   (avg. reading is 80 mmHg)

Question 11

Range of healthy BP

Answer 11

100/70-120/80

Question 12

Range of a hypotensive BP

Answer 12

90/60 and lower

Hypotensive means low BP

Question 13

Range of a hypertensive BP

Answer 13

140/90 and higher

Hypertensive means high BP

Question 14

What is the range of a healthy pulse and what factors does it depend on?

Answer 14

60 to 100 beats per minute

• age
• weight
• level of fitness
• gender
• lifestyle

Question 15

If your lifestyle includes regular exercise, your heart muscle is _______. Therefore, your stroke volume will be _______
so the HR of a fit person will be _______ to produce the _______ cardiac output

Answer 15

Strong; greater; less; same

Question 16

What is the formula for Cardiac Output

Answer 16

Cardiac Output = Stroke Volume X Heart Rate

Question 17

Tachycardia

Answer 17

• heart is beating faster than normal

- could lead to heart not effectively pumping blood

Question 18

Bradycardia

Answer 18

the heart is beating slower than normal

could result in a lack of oxygenated in the body

Question 19

Heart murmur

Answer 19

• caused when a valve in heart does not close completely and blood flows back through the valve
• produces gurgling sound – detected by stethoscope

Question 20

What sound does a heart make when it beats?

Answer 20

lubb-dubb

• atria walls contract and force blood into the ventricles through the tricuspid/bicuspid valves
• when the valves close, a “lubb” sound is produced
• ventricle walls contract and force blood into the arteries through the semilunar valves
• when valves close with ventricular relaxation, a “dubb” sound is produced