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Flashcards in Cardiology Deck (48):
1

hallmark of reversible cellular injury

swelling
ex: angina causes swelling of myocytes with 70% stenosis
subendocardial ischemia will produce ST depression
Swelling is due to failure to maintain ATP generation in hypoxic tissues therefore impaired Na/K ATPase function

2

incomplete occlusion of coronary artery
chest pain at rest

unstable angina

3

vasospasm of the coronary artery causing chest pain

prinzmetal variant angina

4

when does necrosis of the myocardium occur

> 20 min of occlusion of blood flow

5

When does ST elevation occur?

when there is damage to the entire wall of the myocardium => transmural infarct
Will see ST depression when it is subendocardial

6

What marker is helpful in determining another infarction occurring a few days following initial infarction?

CK-MB
troponin-I stays elevated for 7 days but CK-MB elevates within 4-6 hours and returns to normal level within 72 hrs.

7

CO2 produced/O2 consumed

Respiratory quotient (RQ) = 0.8

8

Which gas has a higher diffusion gradient in the alveolus: O2 or CO2?

O2
mixed venous O2 = 40 mm Hg; Alveolar PO2 = 100 mmHg
mixed venous CO2 = 46 mmHg; alveolar CO2 = 40 mmHg
BUT both gases diffuse at the same rate, because CO2 is 20x soluble in water than O2

9

How can volume depletion being assessed on physical exam?

Assess blood pressure while lying and standing. Normally blood pressure is compensated upon standing, but in volume depletion the blood pressure will drop due to decreased preload.

10

important buffering systems in the blood

bicarbonate and proteins (hemoglobin)

11

Apoptosis vs necrosis

Apoptosis is programmed cell death that "fine-tunes" cell populations. Necrosis is pathological and often the result of massive tissue destruction. Necrosis ultimately results in the spilling of cellular contents which invokes INFLAMMATION

12

3 layers of blood vessels (except capillaries)

tunica intima, tunica media, tunica adventitia
Note: the small vessels (vasa vasorum) that supply the large blood vessels with nutrients run through the adventitia

13

How much of the total blood volume do arteries contain?

12%
The small and large veins contain ~60% total blood volume (small veins having 45%)

14

Why does pulse pressure increase with age?

the amount of collagen in large arteries increases with age, decreasing the elasticity

15

major site for regulation of distribution of blood flow and arterial pressure regulation

arterioles

16

Why are capillaries not prone to rupture, but vena cavae can?

Capillaries have a small radius, and the vena cavae have a larger radius. The radius is what determines the wall tension.
LaPlace:
Tension ~ change in P x radius

17

What varies the strength of cardiac muscle cell contraction?

intracellular calcium concentration during cell activation
Depends upon the number of crossbridges
Note: skeletal muscle strength of contraction is controlled by changing the frequency of action potentials

18

What defines the ends of the sarcomere?

Z line
the Z line is composed of alpha-actin

19

parallel bundles of sarcomeres

myofibril

20

contain gap junctions (connexons) for electrical continuity and desmosomes (cadherin) for physical strength

intercalcated discs

21

thin filaments are composed of

F-actin

22

When is the heart muscle perfused?

During relaxation (diastole); the force of contraction impedes blood flow

23

How does calcium ion trigger differ between skeletal muscle and cardiac muscle?

Cardiac muscle intracellular calcium comes from the SR (75%) and ECF (25%). Skeletal muscle only uses SR stores of calcium.

24

How does intracellular calcium get expelled from the cell?

3 Na+-Ca2+ exchanger

25

Pain of angina caused by?

narrowed CAs delivering less oxygenated blood to myocardium, resulting in anaerobic metabolism & production of lactic acid; decreased pH stimulates the pain receptors

26

Why is the great saphenous vein used for CABG?

diameter similar to CA
easily dissected from lower limb
minimal branching

27

Damage to one of the bundle branches of the RCA results in what?

timed contraction of the unaffected branch
late asynchronous contraction of the other ventricle

28

coronary artery that supplies the right ventricle

right marginal
branch of RCA

29

coronary artery that supplies the right atrium

RCA

30

coronary artery that supplies most of the LA & LV as well as the IVS & AV bundles

LCA

31

supplies the LA & LV

circumflex

32

supplies and R & L ventricles, as well as the anterior 2/3 of the IVS

LAD

33

main energy source for the heart

fatty acid oxidation
when energy levels are low, malonyl-CoA decreases, triggering FA uptake
Heart can metab ketones, but not the preferred source

34

2 main hormones that influence energy metabolism in the heart:

catecholamines
insulin
Note: phosphorylation of cardiac isozyme PFK-2 is initiated by insulin

35

balance of FA oxidation and glucose oxidation is regulated by

citrate

36

late marker of MI

troponin T
elevated at 3-5 hrs; remains elevated for 5-10 days
Myoglobin is elevated within 2 hours of symptoms onset but is nonspecific.

37

causes cardiomyopathy in teen years

mutations of phospholamban
Phospholamban association with SERCA2a controls rate of contraction. Decreased SERCA2a activity (mediation of calcium sequestration in the SR) increases relaxation time -> poor pumping action -> left heart failure

38

rate-limiting step of cholesterol synthesis

HMG-CoA to mevalonate**
Enzyme: HMG-CoA reductase (requires 2 NADPH)
mevalonate produces isoprene units which condense to form squalene which cyclizes to form the steroid ring system
Note: most of cholesterol synthesis occurs in the liver

39

Source of all carbons of cholesterol

acetyl CoA

40

major function of HDL

transport of cholesterol to the liver
It also:
transfers ApoE (lipoprotein) and Apo CII to chylomicrons and VLDL

41

When is it acceptable to give a small child aspirin?

Kawasaki disease
symps: rash on palms & soles, enlarged cervical lymph nodes, strawberry tongue
Risk of MI!!! involves the coronary arteries
self-limited disease

42

Modifiable risk factors for atherosclerosis

1. smoking
2. diabetes
3. hypercholesterolemia
4. HTN
Non-modifiable risk factors include: age, male gender, genetics

43

Causes of hyaline arteriolosclerosis (note: small vessel!)

1. long-standing benign HTN
2. diabetes
These patients gets chronic renal failure from glomerular scarring

44

Type of arteriolosclerosis that results from malignant HTN

hyperplastic arteriolosclerosis
fibrinoid necrosis
See onion-skin appearance
get flea-bitten kidney from microhemorrhages

45

causes calcification of the media of the medium arteries
not obstructive and not clinically signficant
might see this on mammography as an incidental finding

Monckeberg Medial Calcification

46

Most common cause or aortic dissection

HTN
Most common cause of death: pericardial tamponade
Inherited CT disorders that can result in weakening of the media:
1. Marfan
2. Ehlers-Danlos

47

complication of thoracic aneurysm

aortic valve insufficiency from ballooning of the aortic root

48

Where does abdominal aortic aneurysm occur?

below the renal arteries but above the bifurcation of the aorta