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Flashcards in Test 1 Deck (59)
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1
Q

What drives blood flow? What is the equation?

A

pressure differences

ΔP = P1 - P2

2
Q

How does pressure difference and resistance affect flow?

A

Flow = Pressure difference (ΔP) / Resistance to flow (R)

increase in pressure increases flow
increase in resistance decreases flow

3
Q

What is the equation for resistance? How is it related to flow?

A

Resistance = length x viscosity / r^4 = 1 / r^4

Flow =ΔP / R =ΔPr^4

4
Q

What is systemic MAP? pulmonary? What accounts for the difference between systemic and pulmonary flow?

A

93 mmHg
10 mmHg

less force generated by right ventricle
less distance blood must travel (decreased resistance)

5
Q

How does pressure change across the circulatory system? Why?

A

it decreases due to resistance

6
Q

What vessel has the greatest resistance?

A

arteriole

7
Q

What is the equation for mean arteriole pressure (MAP)? Pulse pressure (PP)?

A

MAP = diastolic + (PP/3)

PP = systolic - diastolic

8
Q

How is pressure maintained during diastole?

A

Windkessel effect

- elastic recoil of the great vessels

9
Q

How does atherosclerosis affect blood pressure?

A

increase blood pressure

10
Q

What is the equation for cardiac output?

A

CO = stroke volume (SV) x heart rate (HR)

11
Q

How does resistance in series and in parallel affect blood flow? How does this relate to the human CV system?

A

Resistance in series is the sum of all resistance while the resistance in parallel is the inverse of the sum of resistance

This means in parallel circuits, flow will mostly take the path of least resistance.

The human CV system is a parallel system

12
Q

What effect does Ca2+ have on smooth muscle? cAMP?

A

Ca2+ = contraction

cAMP = relaxation

13
Q

What two general factors affect vascular tone?

A

extrinsic factors and intrinsic factors

14
Q

What are the 3 types of extrinsic factors?

A

Hormones

Neuronal (SNS)

Vascular smooth muscle differences

15
Q

What are the types of hormonal extrinsic factors?

A

vasodilators
epinephrine at low levels

vasoconstrictors
angiotensin II
Vassopressin
epinephrine at high levels

16
Q

What are the type(s) of SNS extrinsic factor(s)

A

norepinephrine

17
Q

What are the vascular smooth muscle differences that affect vascular tone?

A

Depending on the location, smooth muscle will either express alpha 1 or beta 2 receptors

18
Q

What are the 3 types of intrinsic factors?

A

myogenic autoregulation

metabolic regulation

endothelium derived factors

19
Q

What is myogenic autoregulation and how does it work?

A

vascular smooth muscle will contract or relax depending of the pressure is too low or too high, respectively

20
Q

What are the two types of metabolic regulation?

A

Activer hyperemia
local tissues will release vasodilators to increase blood flow according to metabolic needs

Reactive hyperemia
local tissues release vasodilators in the event of a clot. The vessel returns to normal diameter when the clot has passed and vasodilators are washed away

21
Q

What are the 2 endothelial derived factors? When are they made?

A

NO
relaxes muscle when drag friction experienced by cell is great

Endothelin
contracts muscle when drag friction experienced by cell is low

22
Q

How does vascular tone determine distribution of blood flow?

A

Organs are connected via parallel circuit. Flow will take the path of least resistance. By increasing and decreasing vascular resistance, the body can direct blow flow according to its needs

23
Q

What is compliance? Where in the cardiovascular system is it highest? Why?

A

Compliance is the ability to stretch and rebound

Compliance is highest in veins, which allows for it to act as a blood reservoir

24
Q

Where are baroreceptors located?

A

in the carotid sinus and in the aortic arch

25
Q

What controls the baroreflex? ow does it work?

A

medulla oblongata

Baroreceptors are mechanoreceptors that respond to pressure. Increased stimulation due to increased pressure tells the medulla to decrease sympathetic outflow and increase parasympathetic outflow. If pressure is low, baroreceptor activation will be low resulting in the increase sympathetic flow and decreasing parasympathetic flow

26
Q

What does ansa cervicalis innervate?

A

superior belly of omohyoid
sternohyoid
sternothyroid
thyrohyoid

27
Q

What does V3 innervate?

A

mandibular branch

anterior belly of digastric
mylohyoid

28
Q

What does VII innervate?

A

platysma
posterior belly of digastric
stylohyoid

29
Q

What does IX innervate?

A

sensory to pharynx, carotid sinus, and carotid body

30
Q

What does XI innervate?

A

SCM and trapezius

31
Q

What does XII innervate?

A

hypoglossus

32
Q

What does prevertebral fascia contain?

A

deep neck muscles

scalenes

33
Q

What does the carotid sheath contain?

A

common carotid a.
IJV
CN X

34
Q

What does pretracheal fascia contain?

A

thyroid gland
trachea
esophagus

35
Q

What does investing fascia contain?

A

trpezius
SCM
CN XI

36
Q

What does superficial fascia contain?

A

platysma
nerves
superficial veins

37
Q

What does superior laryngeal n. innervate?

A

internal laryngeal = sensory for larynx above vocal cords

external laryngeal = motor for cricothyroid

38
Q

What does recurrent laryngeal n. innervate?

A

motor and sensory to larynx below vocal cords

39
Q

What are the general three layers of blood vessels

A

tunica intima:

  • endothelial cells
  • basement membrane
  • internal elastic lamina

tunica media:

  • smooth muscle with varying degree of elastic fibers
  • external elastic lamina

tunica adventitia:

  • Type I collagen
  • Elastic fibers
  • Vasa vasorum
40
Q

Where are elastic arteries found? muscular arteries?

A

elastic:
- aorta, pulmonary artery, branches of great vessels

muscular:
- all other arteries. They distribute blood to organs

41
Q

What are the three types of capillaries?

A

continuous
fenestrated
sinosoids

42
Q

Describe continuous capillaries with regards to their basement membrane and function. Where are they located?

A

continuous basement membrane

highly regulated exchange between tissue and blood

located most place within the body

43
Q

Describe fenestrated capillaries with regards to their basement membrane and function. Where are they located?

A

fenestrated basement membrane

rapid exchange of substances between tissue and blood

kidneys and more

44
Q

Describe sinosoid capillaries with regards to their basement membrane and function. Where are they located?

A

large perforations in basement membrane

maximum exchange between tissue and blood

spleen, bone, and more

45
Q

What causes blood velocity to be low in capillaries?

A

blood velocity = CO/total cross sectional area

the total cross-sectional area of capillaries is extremely large

46
Q

What are the two mechanisms of transcellular exchange?

A

diffusion
- membrane permeable substances move through the cell

transcytosis
- uses vesicles to capture substances by endocytosis and release by exocytosis

47
Q

What drives diffusion? what is the relationship between diffusion and distance?

A

diffusion is driven by a concentration gradient

time of diffusion increases with the square of the distance

48
Q

What is paracellular exchange? How does this relate to capillaries?

A

The passage of substances through spaces between or through cells

exchange of particles is mediated by the type of capillary

49
Q

What is hydrostatic pressure? how does it change over the length of the capillary?

A

hydrostatic pressure = [hydrostatic pressure in capillary] - [hydrostatic pressure in interstitial space]

it decreases

50
Q

What is oncotic pressure? how does it change over the length of the capillary?

A

oncotic pressure = [capillary osmotic pressure] - [interstitial osmotic pressure]

it remains relatively constant

51
Q

What is edema?

A

excess fluid in the interstitium

52
Q

What current is only found in pacemaker cells?

A

If

53
Q

What current is responsible for phase 0 in non-pacemaker cells?

A

INa

54
Q

what current is responsible for phase 0 in pacemaker cells and the calcium influx in phase 2 in non-pacemaker cells?

A

ICa.L

55
Q

What current is responsible for phase 2 and 3 and the repolarization phase in pacemaker cells

A

IKs and IKr

56
Q

What current is responsible for phase 1?

A

ITO

57
Q

What current is responsible for phase 4 in non-pacemaker cells?

A

IK1

58
Q

How does the SNS affect pacemaker cells? How does the PNS?

A

SNS increases the If current

PNS decreases the If current

59
Q

Why is it important to have a long absolute refractory period in the heart?

A

The refractory almost lasts as long as the entire muscle twitch to avoid tetanus