Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Physiology 2 > Unit 1 - CV System The Heart PART B > Flashcards

Unit 1 - CV System The Heart PART B Flashcards

1
Q

The rate of blood flow (F) to tissues & organs is determined by (4 things):

A

a. Pressure gradients (ΔP)
b. Resistance to blood flow caused by friction
c. Poseuille’s Law
d. Velocity of Flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Pressure definition

A

in a fluid is the force exerted by the fluid on its container

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pressure gradients (ΔP) definition

A

differences in pressure b/t 2 locations in the CV system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Blood flows from areas of _____ pressure to areas of _____ pressure, (_____ the pressure gradient)

A

HIGH

LOW

DOWN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Over the entire CV system, pressure is HIGHEST closest to the _______, & ________ as you move further away from this pump

A

VENTRICLES

DECREASES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pressure is highest in ________

A

ventricles & aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lowest pressure in the __________

A

vena cava & atria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If fluid is NOT moving, the pressure it exerts is called ________, & force is exerted _____ __ ___ ______

A

HYDROSTATIC PRESSURE

EQUALLY IN ALL DIRECTIONS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The pressure created in the ventricles is called the _____ _______, b/c __________

A

DRIVING FORCE

it is the force that drives blood through the blood vessels

think: squeezing water balloon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Pressure ____ continuously as blood moves FARTHER from the heart

A

FALLS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In a system in which fluid is flowing, pressure FALLS over distance as __________

A

energy is lost b/c of friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Blood flow is _______ proportional to the size of the pressure gradient (F ∝ Δ P)

A

DIRECTLY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Blood flow is DIRECTLY proportional to the size of the pressure gradient (F ∝ Δ P), therefore:

A
  • the GREATER the pressure difference b/t the 2 locations, the HIGHER the flow
  • the SMALLER the pressure difference, the LOWER the flow
  • WITHOUT a pressure gradient (ΔP = 0), there is NO flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The GREATER the pressure difference b/t the 2 locations, the _______ the flow

A

HIGHER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The SMALLER the pressure difference, the _____ the flow

A

LOWER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

WITHOUT a pressure gradient (ΔP = 0), there is _____ flow

A

NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When fluid-filled container EXPANDS, pressure exerted on the fluid ______,
therefore, when heart RELAXES & EXPANDS, pressure in the fluid-filled chambers _______

A

DECREASES

FALLS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The MEAN BLOOD PRESSURE of the systemic circulation ranges from a high of 93 mm Hg in the _____ to a low of a few mm Hg in the ______ ______

A

AORTA

VENAE CAVAE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Fluid flows only if there is a ________ pressure gradient (ΔP)

A

POSITIVE

19
Q

If the tube has NO pressure gradient, then ____ flow

A

NO

20
Q

Flow depends on the ______ ______, not on the _______ _______.

A

PRESSURE GRADIENT (ΔP)

ABSOLUTE PRESSURE (P)

21
Q

Blood flow takes the path of _____ resistance

A

LEAST

22
Q

Resistance definition

A

tendency of the CV system to oppose blood flow

23
Q

Resistance to blood flow (vascular resistance) caused by ______

A

friction (of blood cells in contact with vessel walls & with each other)

24
Q

What 4 things is vascular resistance determined by?

A
  1. Vessel length (L)
  2. Internal vessel radius (r)
  3. Blood viscosity (ŋ)
  4. The equation: R = 8Lŋ/πr^4
25
Q

Vessel length (L)

A

LONGER blood vessels INCREASE resistance

analogy: don’t need to suck as hard on a short straw as on a long one

26
Q

Internal vessel radius (r)

A
  • DECREASING radius (vasoCONTRICTION), INCREASES resistance
  • INCREASING radius (vasoDILATION), DECREASES resistance
    analogy: drinking milkshake through a fat straw is much easier than through a skinny cocktail straw
27
Q

Vasoconstriction

A

DECREASES blood flow through a vessel

28
Q

Vasodilation

A

INCREASES blood flow through a vessel

29
Q

Blood viscosity (ŋ)

A
  • friction b/t molecules in a flowing fluid
30
Q

Blood viscosity (ŋ) is proportional to ______

A

HEMATOCRIT (the proportion of the blood volume that is RBC’s)

31
Q

INCREASING hematocrit, _______ viscosity, which _______ resistance to blood flow

A

INCREASES

INCREASES

analogy: water (low viscosity) vs honey (high viscosity) moving through a tube
- drinking water through a straw is easier than drinking a thick milkshake

32
Q

What do L & r determine?

A

the SA of the vessel in contact with the blood

33
Q

The MORE SA in contact with the blood, the ______ the resistance

A

HIGHER

34
Q

Explain F = ΔP/R

A

an INCREASE in R, causes a DECREASE in blood flow (F) (& vice versa)

35
Q

Describe the equation: R = 8Lŋ/πr^4

A
  • where 8 & π are CONSTANTS
  • however, in humans, L (vessel length) does NOT change (an exception is the lengthening of blood vessels that occurs in obesity), & ŋ (viscosity) is RELATIVELY constant
  • So R (resistance) is MAINLY determined by changes to vessel radius (R ∝ 1/r^4)
36
Q

What is the exception to L (vessel length) not changing in humans?

A

an exception is the lengthening of blood vessels that occurs in obesity

37
Q

A SMALL change in the RADIUS, produces a _____ change in _______. For example, ______

A

LARGE

RESISTANCE

For example, INCREASING the radius of a vessel by a factor of 2 (e.g. from 2mm to 4mm) DECREASES the resistance by a factor of 16X

38
Q

Poseuille’s Law:

A

Equation that combines the effects that pressure gradients & the factors determining resistance have on blood flow

F = ΔP/R = ΔPπr^4/8Lη

39
Q

Velocity of Flow

A

the distance a fixed volume of blood travels in a given period of time

40
Q

Velocity (AKA velocity of flow)

A

measure of HOW FAST blood flows past a part

41
Q

Formula for Velocity of Flow explained

A

v = Q/A

  • Q = Flow rate (the volume (HOW MUCH) of blood that passes a given point in the system per unit time)
  • A = cross-sectional area of the tube
42
Q

Velocity ______ when cross sectional area DECREASES

A

INCREASES

43
Q

Velocity ______ when cross sectional area INCREASES

A

DECREASES

44
Q

Velocity is ______ in NARROW sections

A

FASTER

45
Q

Velocity is ______ in WIDER sections

A

SLOWER

46
Q

If flow rate (Q) = 12 cm^3/min, that is identical along the length of the vessel that means…

A

that in 1 min, 12cm^2 of fluid flow past point X in the narrow section, & 12cm^3 of fluid flow past point Y in the wide section

Human Physiology 2 (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions