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AU 15 - Human Phys > Cardiovascular Physiology - Lecture 6 > Flashcards

Cardiovascular Physiology - Lecture 6 Flashcards

1
Q

Arteries

A

Main transporters of oxygenated blood
Huge lumen with lots of elastic tissue and some smooth muscle
Blood moves faster in these

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2
Q

Arterioles

A

Aka resistance vessels
Diameter is adjusted to regulate blood flow
There is a huge layer of smooth muscle to help regulate diameter

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3
Q

Capillaries

A

Diffusion occurs across the thin walls

Endothelium is a single cell layer so we can have that exchange

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4
Q

What are the functions of the endothelium in the blood vessels?

A

Serve as a physical lining that blood cells do not normally adhere to in the heart and blood vessels
Serve as a permeability barrier for the exchange of nutrients, meatbolic end products, and fluid between plasma and interstitial fluid; regulate the transport of macromolecules and other substances
Secrete paracrine agents that act of adjacent vascular smooth muscle cells, including vasodilators and vasoconstrictors

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5
Q

How does the amplitude of pressure pulses change as blood moves through the vasculature? Why?

A

The farther from the heart, the lower the pressure and the smaller the amplitude of the pulses
This is probably because of resistance vessels

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6
Q

Pulse pressure

A

Systolic pressure - diastolic pressure

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7
Q

What is blood pressure determined by?

A 
Stroke volume (increase vol = increase pressure)
Speed of the ejection of the stroke volume (increase speed = increased pressure)
Arterial compliance
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8
Q

What is arterial compliance

A

Compliance = /\volume / /\pressure

If somethign is compliant, we can add a lot of volume without changing the pressure

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9
Q

What is the equation for mean arterial pressure?

A

MAP = DP + 1/3(SP-DP)

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10
Q

When we regulate blood pressure, what are we really regulating?

A

Mean arterial pressure

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11
Q

How can the blood move constantly, but the heart only pump intermittently?

A

The blood moved in a single heart contraction stretches out the arteries, so that the recoil continues to push on the blood, keeping it moving during diastole

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12
Q

Mean arterial presure

A

Pressure driving blood into the tissues arranged over the cardiac cycle

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13
Q

What determines the relative blood flow to an organ?

A

Arterioles

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14
Q

What is the equation for flow to an organ?

A

F(organ) = MAP / R(organ)

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15
Q

What happens when the smooth muscles in the arterioles relax? Constrict?

A 
Relax = vasodilation
Constrict = vasoconstriction
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16
Q

Dynamic adjustments in the blood distribution to the organs is accomplished by what?

A

Relaxation and contraction of circular smooth muscles in the arterioles

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17
Q

What is the intrinsic tone of arterioles controlled by?

A

Local controls

Extrinsic controls

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18
Q

What are local controls for intrinsic tone of arterioles controlled by?

A

Active hyperemia = accumulation of CO2, H, eiconsinoids, adenosine, bradykinin, and nitric oxide
Flow autoregulation = myogenic responses (some arteriole smooth muscle respond to increased stretch cause by increased pressure) and reactive hyperemia (respond to cessation of bloodflow)

19
Q

What are the extrinsic controls for the intrinsic tone of arterioles?

A

Sympathetic nerves
Parasympathetic nerves
Noncholinic, noradrenergic autonomic neurons
Hormones

20
Q

What does sympathetic stimulation of alpha-adrenergic receptors result in?

A

Causes vasoconstriction to decrease blood flow to that location

21
Q

What does sympathetic stimulation of beta-adrenergic receptors result in?

A

Vasodilation to cause an increase in blood flow to that location

22
Q

What are the paracrine vasodilators of arterioles?

A

Endothelium derived relaxing factor (EDRF) = NO2

Prostacyclin

23
Q

What are the paracrine vasoconstrictors for arterioles?

A

Endothelin-1

24
Q

Diversity among signals that influence contraction/relaxation in vascular smooth muscles implies what?

A

Diversity of receptors and transduction mechanisms

25
Q

Capillary anatomy

A

Walls are a single endothelial cell in thickness

Primary point exchange between the blood and interstitial fluid - the intercellular clefts assist in this exchange

26
Q

If capillaries lack smooth muscle, how is flow regulated through them?

A

Contraction/Relaxation of circular smooth muscle in upstream metarterioles and precapillary sphincters determine the volume of blood each capillary receives

27
Q

What is an advantage of having blood move slowly through the capillaries?

A

It allows adequate time and surface area for exchange between the capillary blood and ISF

28
Q

Filtration

A

Movement of fluid and solutes out of the blood

29
Q

Absorption

A

Movement of fluid and solutes into the blood

30
Q

Crystalloids

A

Low molecular weight, penetrating solutes

31
Q

Colloids

A

Non-penetrating plasma proteins

32
Q

Pc

A

Capillary hydrostatic pressure (favoring fluid movement out of the capillary)

33
Q

Pif

A

Interstitial hydrostatic pressure (favoring fluid movement into the capillary)

34
Q

TTc

A

Osmotic force due to plasma protein concentration (favoring movement into the capillary)

35
Q

TTif

A

Osmotic force due to interstitial fluid protein concentration (favoring movement out of the capillary)

36
Q

What is the equation for net filtration pressure?

A

Pc + TTif - Pif - TTc

37
Q

At rest, how much blood is in the veins? Can that be changed?

A

60%

Sympathetically mediated venoconstriction can substantially increase venous return to the heart

38
Q

What assists venous flow?

A

Skeletal muscle pump mechanism working in combination with one-way valves

39
Q

What do alterations in venous return alter?

A

Alterations in venous return alter end-diastolic volume (EDV)

40
Q

What does an increase in EDV result in?

A

It directly increases stroke volume and cardiac output

41
Q

What is lymphatic fluid formed by?

A

The slight mismatch between filtration and absorption in the capillaries

42
Q

What is the purpose of the lymphatic system?

A

Return blood to the veins

43
Q

What can cause abnormalities of the lymphatic system?

A

Congenital, traumatic, or infections etiologies

AU 15 - Human Phys (7 decks)

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