CVPR 03-24-14 08-09am Overview CV Anatomy - Proenza Flashcards Preview

► Med Misc 16 > CVPR 03-24-14 08-09am Overview CV Anatomy - Proenza > Flashcards

Flashcards in CVPR 03-24-14 08-09am Overview CV Anatomy - Proenza Deck (64):
1

The functions of the cardiovascular system

1. Distributes dissolved gases & nutrients.
2. Removes metabolic waste
3. Contributes to systemic homeostasis by controlling temp, O2 & nutrient supply, pH, ionic composition.
4. Quickly adapts to changes in conditions and metabolic demands

2

Three parts of the cardiovascular system

1. Heart (pump)
2. Blood (transportation)
3. Vasculature (including lymphatic system) (pipes).

3

Lt vs Rt Heart Side pumps to…

Left side of heart pumps blood to system circulation. Right side pumps to pulmonary circulation.

4

“In Series” arrangement of circulatory system

The primary arrangement of cardiac/pulmonary circulatory system. No direct connection between right and left (septum separates sides). Output of left and right sides of heart must be closely matched.

5

Pulmonary circulation vs. System circulation

A. Pulmonary: low pressure, single pathway between heart and lungs (“series”).
B. Systemic: higher pressure, multiple pathways from heart to different systemic vascular beds (“parallel”).

6

“In Parallel” arrangement of circulatory system ... where occurs

The primary arrangement of SYSTEMIC circulation.

7

Importance of “parallel” arrangement of systemic circulation

1. Oxygenated blood visits only one organ system before returning to pulmonary circulation.
2. Changes in metabolic demand or blood flow in one organ do not significantly affect other organs.
3. Blood flow to different organs can be individually varied to match demand.

8

Changes in blood flow to different organs during rest vs exercise

1. At rest, most blood is directed to brain (~14%), skeletal muscle (~15%), GI system (21%), and kidney (22%).
2. During exercise, up to 80% of blood may be directed to exercising muscle.

9

Major exception to “in parallel” systemic circulation

Hepatic circulation — large fraction of hepatic blood supply is via intestinal circulation

10

Layers of the heart wall

Outside to inside:
1. Epicardium
2. Myocardium
3. Endocardium

11

Epicardium defn.

Outer membrane of the heart wall; Connective tissue & fat

12

Myocardium defn.

Thick middle muscle layer of the heart wall

13

Endocardium defn.

Inner membrane of the heart wall; Made of endothelial cells, as in vessels

14

Pericardium defn.

Fluid-filled membranous sac enclosing entire heart --- Not connected to walls of heart --- Stiff & non-compliant, resists sudden distension of chambers

15

Layers of pericardium

Fibrous layer (outer), Parietal pericardium, [Pericardial fluid], Visceral pericardium (inner)

16

Pericarditis

Inflammation of the pericardium --> restricts filling of the heart

17

Chambers of the heart (4)

Ventricles (left and right) = the main pumping chambers; separated from each other by interventricular septum.........
Atria (left and right) = small “primer” chambers to supply the ventricles with blood; thinner walled.; separated from each other by interatrial septum

18

Left vs. Right Ventricles

Left ventricle supplies higher pressure systemic circulation, so is bigger with thicker walls than the right ventricle. The left ventricle does more work, uses more O2 than the right.

19

Vessels of the Heart (4)

1. Vena cavae --> inlet to rt. atrium from body
2. Pulmonary artery --> outlet from rt. ventricle to lungs
3. Pulmonary vein --> inlet to lt. atrium from lungs
4. Aorta --> outlet from lt. ventricle to body

20

Vena cavae

Superior vena cava & inferior vena cava; Inlet vessels into the right atrium

21

Pulmonary artery

Outlet vessel from right ventricle [Arteries go Away from the heart]...odd for an artery b/c it carries DEoxygenated blood

22

Pulmonary vein

Inlet vessel into left atrium

23

Aorta

Outlet from left ventricle; Main blood supply to body; Garden-hose sized, ~1” in diameter

24

Valves defn.

Thin flaps (“cusps”) of fibrous tissue covered by endothelium...........
*Mitral valve has two cusps (bicuspid); the others have three.

25

Valves of the Heart (4)

1. Tricuspid valve (btwn rt atrium & rt ventricle) .......2. Pulmonic valve (btwn rt ventricle & pulmonary artery)....... 3. Mitral valve (btwn lt atrium & lt ventricle).......4. Aortic valve (btwn left ventricle & aorta)

26

Arrangement of heart valves

Arranged in two sets: Atrioventricular (Tricuspid & Mitral) and Semilunar (Pulmonic & Aortic); All are in the same horizontal plane in the heart

27

Atrioventricular valves – members, location, characteristics

Tricuspid & Mitral valves; Between atria and ventricles; Attached to papillary muscles in ventricles by chordae tendonae

28

Chordae tendonae

Tendon-like attachments that prevent atrioventricular valves from prolapsing into atria during ventricular contraction

29

Semilunar valves – members & location

Pulmonic & aortic valves; Between ventricles & great arteries

30

Valves of the heart – how they work & purpose

One-way, pressure-operated (i.e. passive); Direct blood flow, prevent backward blood flow

31

Heart sounds generation & Valve defects

Heart sounds are generated by opening & closing valves; Defective valves make unusual sounds (murmurs); Regurgitation is a minor valve leakage; Prolapse is a major valve failure, where valve gets pushed backward.

32

Apex vs. Base of the Heart

Apex = tip of left ventricle; Base = posterior surface

33

Coronary blood flow – Effects of Diastole vs. Systole, & Heart Rate

Most coronary blood flow occurs during diastole, b/c of compression of microvasculature during systole.
Flow thus depends on heart rate (less time for perfusion at higher heart rates).

34

Angina

Heart has high oxygen consumption; Supply must closely match demand, or results in chest pain (angina)

35

Right and left coronary arteries – origin, course

Arise from root of aorta; Major coronary arteries course along epicardial surface of heart; Smaller branches enter myocardium; Some variation in anatomy between individuals.

36

Left main coronary artery – size, bifurcations, what it supplies

Short (~1cm); Bifurcates to left anterior descending (LAD) artery and circumflex artery; Primary blood supply to left heart chambers. [LAD = “widowmaker” = its occlusion is very deadly]

37

Right coronary artery – location, what it supplies

In groove between right atrium & right ventricle; Primary blood supply to right atrium and right ventricles, as well as part of left ventricle.

38

Coronary capillaries

Very dense; Each myocyte is associated with several capillaries

39

Coronary veins

Located adjacent to corresponding coronary arteries; Drain into coronary sinus, which opens into right atrium near inferior vena cava

40

Blood flow pathway

DEOXYGENATED BLOOD from systemic circulation --> Superior & Inferior vena cava --> (no valve, passive) Right atrium (contracts) --> (tricuspid valve) Right ventricle (contracts) --> (pulmonic valves) pulmonary arteries to lungs --> OXYGENATED BLOOD from lungs into pulmonary veins --> Left atrium (contracts) --> (mitral valve) Left ventricle (contracts) --> (aortic valve) aorta to systemic circulation

41

3 Parts of the Vascular System

1. Arterial system (to distribute oxygenated blood & nutrients)
2. Microcirculation & lymphatic system (for diffusion & filtration)
3. Venous system (to collect deoxygenated blood & wastes)

42

Types of vessels (flow & size)

Aorta (~25mm, hose) > Arteries (~0.2-6mm)> Arterioles (~10-70 microns) > Capillaries ( Venules / Veins (~10 microns to 0.5 cm)

43

Aorta

Single outlet from left side of heart; Dampens pulsatile pressure

44

Arteries

Thick walled, resist expansion; distribute blood to different organs

45

Arterioles

Relatively thicker walls (more vascular smooth muscle); Highly innervated by autonomic nerves, circulating hormones, and local metabolites; Primary site of regulation of vascular resistances, via changes in diameter.

46

Capillaries

Smallest vessels (walls just a single layer of epithelial cells, with no smooth muscle); ~same size as RBCs, which travel through in single file; Huge total surface area; Primary site of gas & nutrient exchange with interstitial fluid.

47

Venules/Veins

Thin walls relative to diameter compared to equivalent-size arteries (but still some smooth muscle); Not much elasticity; Primary capacitance vessels of the body (most of blood volume stored there); One-way valves compensate for lower pressure in venous system to ensure blood flow only in correct direction

48

Resistance vessels – anatomy

Arterial walls have three layers:
1. Tunica adventitia (outer CT layer, mostly collagen & elastin)
2. Tunica media (middle layer, mostly innervated smooth muscle)
3. Tunica intima (inner layer, lined with single layer of vascular endothelium cells)

49

Tunica media – in which types of vessels, purpose

In all arteries EXCEPT capillaries; Controls diameter of vessels, esp. in resistance arteries

50

Tunica intima – importance

Very important in regulation of blood flow & signaling; Site of atherosclerotic plaque formation

51

Microcirculation defn. & vasculature involved

Vasculature from first-order arterioles to venules; Capillaries

52

Capillaries in microcirculation

Site of gas, nutrient, and waste exchange; Blood flow through determined by pressure gradient and via constriction/dilation of arterioles & precapillary sphincters (no smooth muscle)

53

Precapillary sphincters

Smooth muscle bands around arterioles at junction of arteriole and capillaries

54

What drives movement of substances between capillaries and tissue

Concentration gradients

55

Lymph defn.

Lymph is excess interstitial fluid

56

Lymphatic capillaries

= blind end capillaries; less numerous than regular capillaries & much more porous (no tight junction in lymph vessels as normal capillaries do); have one-way valves (like veins) so lymph flow is uni-directional

57

Lymph flow – what drives it

Passive system; Lymph flows into lymphatic capillaries in response to increased interstitial pressure, contraction of smooth muscle in lymph vessels, and contraction of surrounding skeletal muscle.

58

Lymph flow – direction, path

Uni-directional b/c of one-way valves; Lymph is filtered through lymph nodes (bacteria removed), and rejoins the circulatory system in the subclavian veins.

59

Lymph flow – amount & d efects

Lymph flow ~2-4 L per day (vs ~7000 L blood flood per day); Edema occurs when interstitial fluid exceeds capacity of lymphatic system.

60

Cardiac conduction system -Contraction/Beating of the Heart – what makes it happen

Initiated & coordinated by specialized cells by conducting electrical impulses

61

Sinoatrial (SA) node

In wall of rt. atrium; Spontaneously depolarizes to initiate heart beat; Intrinsic activity ~100 bpm; Highly regulated by autonomic nervous system and many humoral factors; “natural pacemaker”

62

Spread of impulses from SA node

Impulse spreads through atria via gap junctions between myocardiocytes

63

Atrioventricular (AV) node

Between atria and ventricles; Slows conduction to allow atrial contraction to occur before ventricular contraction

64

His-Purkinje system

Specialized cells that rapidly conduct depolarization to trigger coordinated ventricular contraction (increase speed of conduction)

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