Cardiopulmonary: Physiology of the cardiovascular system Flashcards
(32 cards)
1
Q
What are the solid components of blood
A
- red blood cells
- white blood cells
- platelets
2
Q
What is the purpose of a red blood cell
explain how it occurs
A
- binds oxygen via hemoglobin protein
- in the lungs: a high partial pressure of O2 (100 mmHg) allows hemoglobin to almost completely saturate with O2
- in the peripheral tissue: low partial prerssure of O2 causes O2 to release to the tissues
3
Q
What is the function of white blood cells
and what types of WBC are there
A
- potect against foreign bodies
- neutrophils
- eosinophils
- basophils
- monocytes
- lymphocytes
4
Q
What is the function of platelets
A
- aggregate at the site of blood vessel injury
- release serotonin (vasoconstrictor)
- release thromboplastin (blood clotting protein)
5
Q
What are the components of plasma and some of its function
A
- liquid component of blood
- aqueous solution of gas, salts, carbohydrates, proteins, lipids
- clotting proteins
- immune responses
- transportation of lipids, vitamines, hormones
- albumin: plasma protein reponsible for osmotic pressure
6
Q
Normal lab values for
1. hematocit
2. hemoglobin
3. WBC
4. platelets
A
- ~45%
- ~15 g/dL
- WBC: 5x10^9 cells/L
- 250x10^9 cells/L
7
Q
Normal
1. O2 Saturation
2. PO2
3. PCO2
4. pH
5. HCO3
in systemic arteries
A
- 97%
- 90-95 mmHg
- 40 mmHg
- 7.4
- 24 mEq/L
8
Q
Normal
1. O2 Saturation
2. PO2
3. PCO2
4. pH
5. HCO3
in pulmonary arteries
A
- 75%
- 40mmHg
- 46 mmHg
- 7.36
- 28 mEq/L
9
Q
How does the heart coordinate pumping of the upper and lower chambers
A
- action potentials from SA node through the atria to AV node causes atrial contraction
- AV node allows for a brief pause between atrial and ventricular contraction
- AV nodes sends a signal through the rest of the conduction system
- pukinje fibers allow for a fast ventricular depolarization
10
Q
what is an extopic pacemaker
A
- when a cell becomes irritable and is rresponsible for generating a heart beat
- in pathologies that disrupt normal conduction = loss of atria kick to contribute to ventricular filling
11
Q
How is a unidirectional flow in the heart ensured?
A
- via vales
- thin fibrous tissue flaps
- open and close due to pressure changes in the heart
12
Q
What happens with incompetent valves
A
- leaky
- allows reguritation of the stroke volume
13
Q
What happens with stenotic valves
A
- fails to open fully
- forces upstream chambers to contract more vigorously to discharge stroke volume
14
Q
What happens if valve dysfunction occurs chronically vs acutely
A
- dysfunction present fo months to yeas, myocardial hyperrtrophy occus
- acutely such as papillary muscle rupture as a result of an MI = life threatening reduction in pump function
15
Q
Describe each of the elecrical events of the cardiac cycle
A
- P-wave: SA node causes atrial depolarization
- QRS complex: ventricular depolarization masks atrial repolarization
- T-wave: ventricle repolarization
16
Q
Describe the events that occur during ventricular systole
A
- isovolumic contraction: ventricle pressure rises w/o a change in volume (valvles closed)
- rapid ejection: aortic valve opens and ventricle contracts
- slower ejection period: ventricle and aortic pressure fall
17
Q
What is end systole volume
A
- amound of blood left in the ventricle after systole
- about equal to the amound of blood ejected
18
Q
what is ejection fraction
A
- percentage of end diastolic volume ejected during systole
- increased when contraction is augmented (exercise)
- decreased when force is diminished (pathology)
19
Q
describe ventricular diastole
A
- isovolumic relaxation: period is the initial phase of diastole; aortic valve closes and ventricular pressure falls
- when ventricular pressure falls below atrial pressure the mitral valve opens
- ventricular filling is completed when the P-wave initiates next cycle atrial kick
20
Q
What is cardiac output
A
- stroke volume x HR
- stroke volume = the amount of blood pumped each heart beat
21
Q
What intrinsic factors affect stroke volume
A
- preload
- force frequency
- afterload
22
Q
What is preload
A
- refes to the amount of stretch prior to contraction
- end diastolic volume
23
Q
What is force-frequency relationship
A
- increase in heart rate = increase in myocardial force generation
24
Q
What is afterload
A
- the force against the ventricles that the ventricles must overcome to pump blood
25
What are some extrinsic factors on stroke volume
- norepinephrine: increases inotropic state (force of contraction)
- acetylcholine: negative inotrophic state
26
What are some factors that regulate heart rate
- neural regulation: SNS/PsNS
- chemical regulation
27
What are arterioles and what is their main function
- small muscular vessles
- constrict or dilate based on the activity levels of the tissue they supply
28
What is hypoxic vasoconstriction in the lungs?
- occurs in regions of the lungs where O2 is poor
- important during fetal life
- postnatal life can be beneficial when portion of the lungs become obstructed
- if the whole lung is obstructed due to pathology this can lead to right sided heart failure
29
How is arterial flow regulated
- innervated by sympathetic nerve fibers
- when the SNS nerve fibers activate = vasoconstriction
- baroreceptors and chemoreceptors monitor homeostasis and modulate the level of activation
- vascular endothelium is local regulator of smooth muscle (releases vasodilators and vasoconstrictors)
30
How is fluid exchanged on the arterial end of a capillay
- high intravascular pressure and low interstitial pressure and a high osmotic pressure causes fluid to move out of the vascular system (filtration)
- both intravascular and interstitial pressure are high but lower than osmotic pressure causes movement into the vascular system (reabsorption)
31
How is venous flow and volume regulated
- splanchnic and skin veins are innervated by SNS which casues venoconstriction
- this reduces capacitance of venous bed and increases venous return
- breathing: diaphragm descends = increased intra-abdominal pressurre/decreased intrathorracic pressure = moves fom IVC to right atrium
32
Describe how coronary blood flow is regulated
- epicardial arteries form endocardial ateries
- venous blood drains to right atrium via cardiac veins and coronary sinus
- arteries are compressed during systole and therforer must fill during diastole
- diastolic pessure is main determinant of coronary pefusion pessure
