CV A&P and Systemic circulation ppt <3 <3 <3 Flashcards Preview

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Flashcards in CV A&P and Systemic circulation ppt <3 <3 <3 Deck (116)
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1
Q

the average heart weighs how much

A

250- 350 grams

2
Q

3 main components of the myocardium

A

RV wall

LV wall

Myocyte

3
Q

The RV wall is how thick?

A

0.3-0.5 cm thick

4
Q

The LV wall is how thick?

A

1.3-1.5 cm thick

just know that basiclly the LV is over twice as thick

5
Q

5 components of the myocyte

A
  1. cell membrane + T tubules
  2. Sarcoplasmic reticulum (SR)
  3. Contractile elements
  4. Mitochondria
  5. Nucleus

**** huge volume of mitochondria!!!!!****

6
Q

The huge volume of mitochondria in the myocyte means what????

A

aerobic metabolism

7
Q

what is greater than 90% of the volume of the myocardium

A

the myocyte

8
Q

*****************************

what is the contractile elemement of the myocyte?

A
  • sacromere (actin and myocin filaments)

A sarcomere (Greek sárx = “flesh”, méros = “part”) is the basic unit of a muscle. Muscles are composed of tubular muscle cells (myocytes or myofibers). Muscle cells are composed of tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as dark and light bands. Sarcomeres are composed of long, fibrous proteins that slide past each other when the muscles contract and relax.

Two of the important proteins are myosin, which forms the thick filament, and actin, which forms the thin filament. Myosin has a long, fibrous tail and a globular head, which binds to actin. The myosin head also binds to ATP, which is the source of energy for muscle movement. Myosin can only bind to actin when the binding sites on actin are exposed by calcium ions

9
Q

****************************

Sacromeres are integrated by what?

A
  • intercalated disk and gap junctions

intercalcated disk are microscopic identifying features of cardiac muscle. Cardiac muscle consists of individual heart muscle cells (cardiomyocytes) connected by intercalated discs to work as a single functional organ or syncitium. By contrast, skeletal muscle consists of multinucleated muscle fibers and exhibit no intercalated discs. Intercalated discs support synchronised contraction of cardiac tissue. They occur at the Z line of the sarcomere and can be visualized easily when observing a longitudinal section of the tissue.

Three types of adhering junctions make up an intercalated disc — fascia adherens, macula adherens and gap junctions.
Fascia adherens are anchoring sites for actin, and connect to the closest sarcomere.
Macula adherens stop separation during contraction by binding intermediate filaments, joining the cells together. Macula adherens junctions are also called desmosomes.
Gap junctions allow action potentials to spread between cardiac cells by permitting the passage of ions between cells, producing depolarization of the heart muscle

10
Q

What are 3 specialized myocytes?

A
  1. SA node
  2. AV node
  3. bundle of his
11
Q

***************************

Which leads shows an inferior MI?

what artery is invloved

A

II, III, AVF

Right Coronary Artery

12
Q

Which leads shows a Lateral MI?

what artery is invloved

A

I, AVL, V5, V6

Left Circ

13
Q

**************************

Which leads shows an Anterior MI?

what artery is invloved

A

V3-V4 (I, AVL)

Left Coronary artery

14
Q

**************************

Which leads shows an Anteroseptal MI?

what artery is invloved

A

V1-V2

LAD

15
Q

myocardial circulation occurs mostly during what?

and why

A

diastole

BC of interruption of blood flow during
systole, due to mechanical compression of vessels by myocardial contraction and the
absence of anastomoses between the left and right coronary arteries

16
Q

what is the average ml/min of myocardial circulation?

A

200-250 ml/ml

17
Q

*******************************************

Another characteristic of the coronary circulation is that maximal oxygen extraction of ___1__ %
occurs, resulting in a coronary venous oxygen saturation of about __2____%.

A
  1. 70%
  2. 30%
18
Q

what is the coronary sinus

A

a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium) and It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.

19
Q

The coronary sinus is what % of venous return?

A

75%

(it seems like a lot but thats what his slides say and I cound’t find anythng in the book slide #10)

20
Q

what veins make up the coronary sinus?

A

posterior veins

RV=anterior veins

Thebesian veins (shunt)

21
Q

Layers of the heart

A

parietal pericardium

epicardium (visceral pericardium)

myocardium

endocardium

22
Q

Most of the oxygenated
blood reaching the fetal heart is from the ____1____ vein and the __2___ __2___ __2____

A
  1. umbilical
  2. inferior vena cava
23
Q

what is the fetal blood flow starting with the IVF

A

oxygenated blood from the IVC goes into the RA then
diverted through the foramen ovale to the LA to the LV then pumped out the aorta to the head

IVC > RA > FO > LA > LV > AO > systemic (head)

24
Q

What is fetal circulation starting with the SVC

A

Deoxygenated blood from the superior vena cava enters the RA goes to the RV, then enters the (PA) the pulmonary artery goes through the patent ductus arteriosus (PDA) to the aorta to the feet and umbilical
arteries.

SVC > RA > RV > PA > PDA > AO > systemic (feet)

25
Q

in the fetal circulation the RV makes up what part of CO

A

2/3

26
Q

anatomic closure of the PDA occurs when after birth

A

2-3 weeks

27
Q

what are the 2 main classification of valves in the heart

A

AV

semilunar

28
Q

WHat are the 2 AV valves

A

tricuspid

mitral

29
Q

what are the 2 semilunar valves of the heart

A

aortic and pulmonic

30
Q

what is the blood flow through the heart then into circulation? (17 steps, once you leave the heart gets more basic)

A
  1. RA
  2. tricuspid
  3. RV
  4. pulmmonic valve
  5. PA
  6. lungs
  7. PV
  8. LA
  9. mitral valve
  10. LV
  11. Aotic valve
  12. aorta
  13. atreries
  14. aterioles
  15. capillaries
  16. venules
  17. veins
31
Q

what do arteries do

A

transport blood under high pressure

32
Q

what do arterioles do?

A

contract and dilate to control blood from into the capillaries

(control resistance)

33
Q

what do capillaries do?

A

sites for transfer of oxygen and nutrients and recipients of metabolic byproducts

34
Q

venules

A

collect blood from capillaries for delivery to veins

35
Q

what do veins do?

A

contract or expand to store blood, venos pump mechanism.

36
Q

what allows veins to return blood to heart

A

one-way valves and skeletal muscle pumping

37
Q

what are the 3 layers of arteries and veins from inner to outer

A
  1. Tunica intima
  2. Tunica media
  3. Tunica adventitia
38
Q

what layer is smooth muscle fibers mixed with elastic fibers?

A

tunica media (middle)

39
Q

what layer is squamous epithelium, connective tissue, and basement membrane

A

tunica intima

40
Q

what layer is a thin layer of connective tissue-lengthwise elastic or collagenous fibers?

A

tunica adventitia

41
Q

the systemic circulation is accountable for what % of blood volume?

A

80%

42
Q

there is low resistance in systemic circulation until arterioles! what are the pressures at the folowing:

Arterioles

Capillaries

Venous end

A

Arterioles- 85 mmHg

Capillaries- 30 mmHg

Venous end- 10 mmHg

43
Q

The arterioles account for _____% of the resistance of systemic circulation?

A

50%

44
Q

what is pulse pressure

A

difference of systolic and diasyolic b/p

45
Q

what does the dicrotic notch indicate?

A

closure of the aortic valve

46
Q

the pulse pressure reflects what?

A

stroke volume and resistance/compliance

47
Q

the pulse pressure wave form is ______ peripherally in good compliance and goes to almost nothinfg in the capillaries

A

amplified

48
Q

4 determinants of tissue flow

A
  1. pressure gradien/resistance
  2. Resistance only calculated
  3. distensibility
  4. compliance
49
Q

Resistance is ___1___ proportional to pressure and __2__ proportional to flow

A
  1. Directly
  2. Inversely
50
Q

*****************

________ are less musclular, leading to 6-10 x’s more distensible.

(arteries or veins)

A

Veins

51
Q

what are the 4 main things for control of tissue blood flow

explian each!!

A
  1. Local control-(based on the need for delivery of oxygen or other nutrients)
  2. Autoregulation-(local mechanism in which a specific tissue is able tomaintain a relatively constant blood flow over a wide range of mean arterial pressures)
  3. Long-term control-(change in vascularity of tissues with sustained increases in blood pressure, increased metabolism, inadequate oxygen delivery)
  4. Autonomic nervous system control- (norepinephrine influences resistance to
    redistribute tissue blood flow; prominent in the kidneys and skin and
    minimal in the cerebral circulation)
52
Q

what controls systemic b/p?

A
  1. Changes in CO and SVR
  2. Autonomic
  3. Baroreceptors
  4. Chemoreceptors
  5. Atrial reflexes
  6. CNS
  7. ischemic reflex
  8. Hormonal
53
Q

Baroreptors (control of Systemic b/p)

  1. located where?
  2. respond rapidly to what?
  3. respond with the sympathetic regulation of what center?
A
  1. walls of carotids and aortic arch
  2. b/p changes
  3. Vasomotor center
54
Q

Chemoreptors (control of systemic b/p)

  1. Located where?
  2. stimulated by what?
  3. respond with regulation from what center?
  4. slower responses to b/p and faster action in stimulating what?
A
  1. Carotid and aortic bodies
  2. by decrease O2/ increased CO2/ increased H+
  3. Vasomotor center
  4. respirations
55
Q

************

in recap baroreptors do what mainly?

and Chemoreceptors do what mainly?

A
  • respond to B/P Incr/decres
  • stimulate respirations
56
Q

Atrial reflexes (in control of systemic b/p)

  1. Are mediated by what?
  2. what do they do when there is more stretch?
  3. the increased HR is a functino of direct stretch of ____ _____ as well as the bainbridge reflex.
  4. it releases what atrial granules?
  5. what does that atrial granule do?
A
  1. stretch
  2. decrease b/p and increase HR
  3. SA node
  4. Atrial natriuretic peptide (ANP)
  5. decrease preload, decrease afterload, decrease sensitivity to ADH
57
Q

RAAS system does what in response to

  1. Low BP
  2. Increased BP
A
  1. retain Na+ (water)
  2. excrete Na+ (water)
58
Q
A
59
Q

********************************

The normal cardiac action potential results from timedependent changes in the permeability of cardiac muscle cell membranes to __1__, __2__, __3__, __4__ ions during phases __5__ of the action potential

A
  1. Na+
  2. K+
  3. Ca++
  4. Cl-
  5. 0 to 4
60
Q

*********************************

Ion movement for phases of cardiac action potential

Phase ion Movement across cell membrane

A

Phase ion Movement across cell membrane

0 Na+ IN (if Na+ K+ out)

1 K+ OUT

                 Cl<sup>-</sup>                IN

2 Ca+ IN

                  K<sup>+</sup>               OUT

3 K+OUT

4 Na+ IN

61
Q

what are the 2 elements that contribute to tension (force) of the heart muscle

A
  1. contractile element (active tension)
  2. Elastic element (resting tension)
62
Q

what influences tension of the heart?

A

length of muscle fibers

63
Q

what is the starlings relationship to heart muscle mechanics and tension

A

tension (active and resting) vs Length

64
Q

Velocity is influenced by what?

A

length and tension

65
Q

in recap the heart muscle mechanics function off 3 main things __1___, __1__, __1__.

tension is made up of __2__ and __2__ tension.

the length of the muscle fibers influence the __3__. such as in starlings law

and the velocity is influenced by both __4__ and __4__.

A
  1. tension, length, velocity
  2. active and resting
  3. tension
  4. length and tension
66
Q

CO=

A

HR x SV

67
Q

SV is affected by what 3 things

A
  1. Preload
  2. After load
  3. contractility
68
Q

Law of LaPlace relates what 2 things?

A

ventricular pressure and wall tension

T= Pr / 2h

69
Q

tension =

A

pressure gradient x radius

70
Q

Laplace law in r/t to the heart

A

in the LV increased filling > increased wall pressure

71
Q

6 phases of the cardiac cycle

A
  1. isovolumetric ventricular contraction (contracting constant volume)
  2. Rapid ejection phase
  3. Reduced ejection phase
  4. Isovolumetric relaxation
  5. Rapid filling phase
  6. slow filling period
72
Q

the atrial contributation to the cardiac cycle can be __ to ___ % in the failing heart

A

20-30%

73
Q

what 4 things determine myocardial function?

A
  1. preload
  2. Afterload
  3. Contractility
  4. HR
74
Q

preload

In normal heart and increased venous return results in an __1__ CO.

In a failing heart the sacromere length is already maximal; so CO increases requires increased __2__ or __2__.

A
  1. Increased
  2. contractility or HR
75
Q

what is the pressure applied to fill the heart and is represented by the “passive” pressure- volume curve

A

preload

76
Q

clinically preload is measured by what?

A

end diastolic pressure

LVEDP

77
Q

typical values for LVEDP is what

A

4-5 mmHg

78
Q

a sudden increase in filling pressures. (preload) will cause what? 3 main things

A
  1. increased LVEDP
  2. increased heart contraction force ( do to the enhanced thick and thin filament overlap, it contracts to the same ESV- starling law)
  3. increased SV, CO, PA
79
Q

what is the pressure in the aorta throughout the ejection phase? it is an estimate if arterial pressure

A

afterload

80
Q

a sudden increase in mean arterial pressure (afterload) causes what 3 things to happen

A
  1. pressure in the ventricle must rise to a higher level during the isovolumetric contraction phase before the aortic valve will open
  2. ejected volume goes down
  3. SV and CO woll decrease
81
Q

a sustained increase in the mean arterial pressure (afterload) is caused by what?

A
  1. the increased ESV plus normal venous return that leads to increased EDV
  2. the increased EDV makes the heart contract more forcefully (starlings law)
  3. causing increased SV, CO, PA
82
Q

altered contractile force is due to the change in the rate or quality of __1__ delivered to the myofilaments, or a change in the affinity or the filaments to __2__.

A
  1. Ca++
  2. Ca++
83
Q

******************

a sudden increase in contractility causes what 2 things

A
  1. the heart to contract more forcefully from ANY initial length
  2. the heart to contract more forcefully during EJECTION phase, leading to decreased ESV and increased SV
84
Q

what are the effects of a sustained increase in contractility?

A
  1. reduced ESV plus normal venous return = reduced EDV
  2. heart contracts less forcefully dur to EDV
  3. pressure voume curve shifted to left
85
Q

*******************

explain the cardiac cycle and pressure loops

A
  1. ISOVOLUMETRIC RELAXATION (diastole) causes pressure to decreases
  2. as passive VENTRICULAR FILLING (diastole) occurs, and volume begins to increase
  3. as ATRIAL KICK finishes and volume is maxed pressure increases during ISOVOLUMETRIC CONTRACTION (systole)
  4. followed by rapid EJECTION (systole) as pressure continues to increase very slightly and volume decreases greatly
  5. this leads into REDUCED EJECTION thus lowering pressures and volume and starting cycle over again with ISOVOLUMETRIC RELAXATION
    6.
86
Q

better pic of the cardiac loops

A
87
Q

**************

what occurs during the diastolic phase of the cardiac cycle

A
  1. isovolumic relaxation
  2. filling
  3. atrial kick
88
Q

*********

what occurs during the systole phase of teh cardiac cycle?

A
  1. isovolumic contraction
  2. ejection
  3. rapid and reduced ejection
89
Q

****************

so now that we learned all of the phases of the cardiac cycle match them up with what is going on in the heart

1st draw a pic then explain it

A
  1. during isovolumetric relaxation (diastole)– constant radius (all valves are closed) decreased pressure and tension
  2. during passive filling AV valves open allowing VENTRICULAR FILLING (diastole) causinga constant pressure with increased radius and tension,
  3. after ATRIAL KICK all valves are closed
  4. constant radius increased pressure and tension. during ISOVOLUMETRIC CONTRACTION (systole)
  5. then Semilunar valvees open during rapid ejection
  6. and EJECTION (systole) occurs with constant tension decreased radius and increased pressure
  7. followed by reduced ejection and all valves closed.

-during each phase (or side of the loop) there must be a radius, pressure, and tension.

– the ones ont the right and left have same radius (isovolumetric) (they are not gaining any volume. the left is diastolic loses pressure and tension, the right is the systolic it is gaining pressure and thus tension

  • the bottom is straigt filling (diastolic) so a constant pressure. ( no flunctuations) but the radius gets bigger (from more fluids) and thus the tension gets larger.

– the top or ejection is not a constant pressure b/c it has rapid and slowed ejection. but tension is always the same )constant b/c it is one big squeeze. so during ejection we are losing volume so radius decreases, and we are forcing the blood out fast so pressure is increased.

– when all valves are closed the radius is constant (can only fill whats there.

this is bringing it all together!!!!!!!!!!!!!!!!!!!

90
Q

explain A-B

A
  • filling phase (ventricular filling)
  • diastole
  • encompasses both passive and atrial kick
  • constant pressure
  • increased radius
  • increased tension
91
Q

explain B-C

A
  • Isovolumetric contraction
  • systole
  • radius constant
  • tension increased
  • pressure increased
92
Q

Explain C-D

A
  • Ejection phase
  • systole
  • encompasses both rapid and reduced ejection
  • tension constant
  • radius decreases
  • pressure increases
93
Q

explain D-A

A
  • Isovolumetric relaxation
  • diastole
  • radius constant
  • pressure decreases
  • tension decreases
94
Q

what occurs in the cardiac pressure volume loop in the filling phase

A
  • AV valves open
  • ventricular volume increases to maximum (EDV)
  • pressure constant (rises just slightly EDP)
95
Q

what occurs in the cardiac pressure volume loop during the isovolumetric contraction phase

A
  • mitral valve closes
  • ventricular pressure increases without volume change
96
Q

what occurs in the cardiac pressure volume loop in the ejection phase

A
  • when ventricular preesure exceeds aortic pressure aortic valve opens, and ejection begins (volume decreases)
  • initially pressure continues to rise but then falls
97
Q

what occurs in the cardiac pressure volume loop in the isovolumetric relaxation phase

A
  • aortic valves closes
  • volumes in ventricle is ESV
  • pressure in the ventricle falls until the AV valve opens (back to step 1)
98
Q

CO is the product of what?

A

HR x SV

99
Q

what is Stroke Volume (SV)

A

difference between EDV and ESV

100
Q

********************

what is ejection fraction?

how is it calculated

A
  • the amount of blood ejected in each beat
  • SV divided by EDV

EDV-ESV / EDV = EF

101
Q

****

normal EF is what?

A

60-65%

102
Q

an EF of what is indicative of severe Cardiac disease?

A

<40%

103
Q

what is 2 ways to control CO

A

intrinsic control

extrinsic control

104
Q

which type of control for CO, rapidly compensates for changing conditions an dequalizs R and L outputs

A

intrinsic

105
Q

what is an example of intrinsic control of CO

A

HR

SV (starling law)

106
Q

Which control of CO changes in contractility (inoropic state)

A

extrinsic

107
Q

what are 4 factors that increase O2 consumption?

A
  1. Increased afterload or contractility
  2. dilation of ventricular chamber
  3. Increased HR
  4. Increased SV

(basically anything that raises B/P will increase myocardinal O2 requirements)

108
Q

what determine MAP

A

the product of CO an dtotal peripheral resistance

109
Q

CO is propprtional to

A

the pressure diff b/t aorta and right atrium

110
Q

CO is inversly proportional to

A

resistance of circulatory system

111
Q

automaticity

what sets the pace

A

the fastest rate

112
Q

is automaticity of the heart neurally mediated

A

nope

it is neurally modified though

113
Q

how does ACh modify rate and automaticity

A

increases K+ current and slows rate of spontaneous depolarization

114
Q

how does epinephrine modify rate and automaticity

A

increases Ca++ current

(CCB have opposite effect)

115
Q

with ionic NODAL ACTION potentials

What is the unstable “resting” potential?

what are it;s ion currents

and what occurs due to this

A

~ -60 mV

K+ current present but declining

Increasing Na+ and Ca++ currents

causes SPONTANEOUS DEPOLARIZATION

116
Q

****************

with ionic NODAL ACTION potentials

the membrane potential reaches threshhold at ~-40 mV

and what occurs

A

rapid increase in Ca++ T-type current

fall in IC K+, then willl increase later

Cell reaches 0 to +5 mV