Nordgren Cardiac Phys week 2 Flashcards Preview

CRRAB 1 > Nordgren Cardiac Phys week 2 > Flashcards

Flashcards in Nordgren Cardiac Phys week 2 Deck (40):
1

Passive transcapillary solute diffusion depends on (4 things):

1. concentration gradient

2. surface area

3. diffusion difference

4. permeability of capillary wall to the substrate

2

Net fluid OUT of capillary = ?

filtration

3

Net fluid INTO capillary = ?

rebsorption

4

Pressure of blood forcing fluid OUT of capillary?

Hydrostatic

5

Attraction of water IN to regions of higher protein concentration?

Oncotic pressure

6

Starling's Hypothesis:

Net filtration rate = ?

Positive net pressure gradient = ?

Negative net pressure gradient = ?

(P intracapillary - P interstitial) - (oncotic pressure of intracapillary fluid - oncotic pressure of interstitial fluid)

Positive net pressure gradient = filtration

Negative net pressure gradient = Reabsorption

***hydrostatic and oncotic pressure of IF are usually zero

***oncotic pressure usually does not change

7

Location of Filtration?

arteriole end of capillary

8

Location of Reabsorption?

venule end of capillary

9

What can cause the oncotic pressure to drop?

Histamine release--increases capillary permeability to protein.

10

Total resistance for vessels in a series = ?

the sum of each individual resistance

Q = total change in P / total R

11

Primary blood volume reservoir?

peripheral venous system

12

secondary blood volume reservoir?

central venous system

-great veins of the thorax and right atrium

13

Overall resistance to flow through the ENTIRE systemic circulation?

TPR

total peripheral resistance

14

Adding and organ in parallel to the system will _______ the TPR.

decrease

15

compliancy (C) = ?

C = change in V / change in P

** veins have much greater C than arteries

16

Pressure reservoir?

Arteries

**small change in V builds up a lot of P --> recoils to drive blood through the periphery

17

Relate MAP, CO, and TPR:

MAP = CO x TPR

**MAP also = Pdias + 1/3(Psys -Pdias...PP)

or

MAP = 2/3Pdias + 1/3Psys

18

relate pulse pressure, stroke volume and compliance.

PP = SV/C arterial

19

Vascular smooth muscle contraction depends on?

Ca2+

20

Basic pathway for Ca2+ mediated VSM contraction:

1. Ca2+ + calmodulin

2. activation of myosin light chain kinase

3. MLC kinase + ATP --> phosphorylation of MLC protein --> MLC-PO4

4. cross bridge formation and cycling, energy from ATP --> tension development/shortening

**5. removal of phosphate from MLC returns cell to relaxation

21

Resting membrane potential of VSM?

-40 to -65 mV

**determined by K+ permiability

22

two causes of VSM action potentials:

1. slow inward Ca2+ current (like pacemaker cells)

2. stretch sensitive cation channels

23

In addition to membrane depol, how else can Ca2+ get into VSM cell?

Pharmacomechanical coupling (vasoconstrictor agonist)

G coupled protein receptor, IP3 (opens Ca2+ channels in SR)

24

2 methods for VSM relaxation:

1. hyperpolarization

2. chemical vasodilators --> Beta2 receptors --> increased cAMP/cGMP --> active protein kinase A --> lots of phoshorylation --> Ca2+ efflux, hyperpol, decreased contractile machinery sensitivity to Ca2+

25

Most important means of local arterial flow?

Metabolic

Dilation: low O2, high CO2/H+/K+, release of adenosine

26

Endothelial cells effect on arterial tone?

NO --> increased cGMP

27

NO production stimulated by?

Ach, bradykinin, vasoactive intestinal peptide

28

Other chemicals involved in control of arterial tone?

Prostaglandins, thromboxane

29

Active phase of VSM reacting to change in transmural pressure:

myogenic respone

30

Most important means of reflex control in vasculature?

SNS vasoconstrictive nerves

31

NT and receptor for SNS vasoconstriction

NE, a1

32

Hormonal influence for vasoconstriction and its receptor?

Vasopressin (ADH) -- a1

33

Hormonal influence for vasodilation and its receptor?

Angiotensin II -- Beta2 (more sensitive to epi than a1)

34

Is venous tone subject to local metabolic needs?

nope

35

What is the pressure of the circulatory system if there were no flow?

7 mmHg

"Mean circulatory filling pressure"

36

Two major variables that affect mean circulatory filling pressure:

1. circulating blood volume

2. state of peripheral venous tone

37

Central integration of the baroreceptor reflex occurs where?

medullary cardiovascular centers

38

where are baroreceptors located?

1. aortic arch

2. carotid sinuses

39

When do PNS and SNS work in concert instead of reciprocally?

Dive reflex

40

RAAS?

Renin, angiotensin, aldosterone system

**increased aldosterone increases Na+ reabsorption in the kidneys --> water follows