Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
What is systemic arterial pressure?
|
Time varying pressure within the systemic arterial system
The potential energy that drives the circulatory system |
|
|
Systemic arterial pressure is analogous to what in an electrical circuit?
|
Voltage
|
|
|
Wrt to regulation, how strictly is systemic arterial pressure regulated?
|
Regulated within a relatively narrow range
|
|
|
What regulates that amount of blood flow into a particular vascular bed?
|
The bed's vascular resistance
|
|
|
When managing patients with CV disease, in addition to systemic arterial pressure, what else is important?
|
Blood flow and tissue perfusion
|
|
|
What is the equation in fluid mechanics that is analogous to ohm's law in electrical currents?
|
Fluid Resistance = ΔP / F
P = pressure drop across vascular bed F = flow through the vascular bed |
|
|
What is vascular reisstance?
|
Resistance that opposes flow of blood through a vascular bed
|
|
|
What are the 2 categories of mechanisms that regulates systemic arterial pressure in the short term?
|
1. Health - Posture, post-prandial state, physical exercise
2. Disease - shock, heart failure |
|
|
What are 2 mechanisms that regulate systemic arterial pressure in the long term?
|
1. Hypertension
2. Antihypertensive and vasodilator drugs |
|
|
What are the 5 components of systemic arterial regulatory mechanisms?
|
1. Pressure sensor
2. Afferent neural pathway 3. Central neural coordinating center 4. Efferent neural pathway 5. Effects that modulate parameters that affect systemic arterial pressure |
|
|
What is systolic pressure?
|
The peak value that pressure reaches during ventricular systole
|
|
|
What is diastolic pressure?
|
The lowest value that pressure reaches during ventricular diastole
|
|
|
What is pulse pressure?
|
The difference between systolic and diastolic pressure
|
|
|
What is mean pressure?
|
The time averaged pressure over the entire cardiac cycle
|
|
|
Wrt to an equation, what is systemic vascular resistance equal to?
|
Systemic Vascular Resistance = Mean Arterial Pressure / Cardiac Output
|
|
|
What is the unit for vascular resistance?
|
Wood unit
|
|
|
What are 4 changes that the circulatory system must adapt to?
|
1. Temperature changes
2. Changes in local vascular bed metabolic requirements 3. Disorders (fever, sepsis, blood loss) 4. Gravitational effects |
|
|
What is the neural control center of the circulatory system?
|
Medulla
|
|
|
What are 3 short term systemic arterial pressure sensors?
|
1. Arterial baroreceptors
2. Ventricular baroreceptors 3. Atrial baroreceptors |
|
|
What is a long term systemic arterial pressure sensor?
|
Renal baroreceptor
|
|
|
What are arterial baroreceptors and where are they located?
|
Stretch receptors located in the carotid sinus and aortic arch
|
|
|
What are the afferents and efferent pathways for arterial baroreceptors?
|
Afferents: IX (glossopharyngeal) and X (vagus)
Efferents: Sympathetic and parasympathetic systems |
|
|
When do baroreceptors fire?
|
Increase rate of discharge as pressure increases
(Show CHANGE in pressure, resetting occurs after) |
|
|
What atrial baroreceptors are more concerned with volume than pressure?
|
Baroreceptors that sense atrial distension and stimulate the release of Atrial Natruiretic Peptide
|
|
|
What is the action of Atrial Natruiretic Peptide?
|
Duiretic action to decrease intravascular volume
|
|
|
What is the renal baroreceptor that is concerned with volume?
|
Juxtaglomerular apparatus - releases renin which leads to production of angiotensin II
(Arteriolar vasocontriction and augments retention of Na+ and H2O) |
|
|
Cardiac performance is mediated by what NS?
|
Autonomic NS - sympathetic and parasympathetic NS
|
|
|
What are the 2 types of direct neural input on the heart?
|
1. Adrenergic (NE, sympathetic)
2. Muscarininc (AcTH parasympathetic) |
|
|
Where within the heart is parasympathetic input directed, what are its effects?
|
Input is predominantly to the SA and AV nodes
Slows sinus HR and prolongs conduction in AV node |
|
|
Where within the heart is sympathetic B adrenergic inputs, what are its effects?
|
Input to all parts of the hearts
Increases Sinus HR, speed conduction in the AV node and increase myocardial inotropic state |
|
|
Vascular resistance is regulated by what physical characteristic of the arterioles?
|
The diameter of the systemic arterioles
|
|
|
What is the principal determinant of local vascular resistance?
|
Local metabolic rate - mediated via adenosine release
|
|
|
Which vascular beds vasoconstrict in response to A-adrenergic input?
|
Renal, mesenteric, cutaneous (don't need blow flow there in crisis mode)
|
|
|
Which vascular beds vasodilate in response to B adrenergic input?
|
Skeletal muscle
|
|
|
What are 3 additional molecules that promote vasodilation?
|
Adenosine, prostacyclin, NO
|
|
|
What are 3 additional molecules that promote vasoconstriction?
|
1. Angiotensin
2. Endothelin 3. Thomboxane |
|
|
The volume of body fluids is regulated by what?
|
By renal regulation of Na+ and H20 excretion
|
|
|
What are 3 effector mechanisms of the kidney?
|
1. Intrinsic renal hemodynamics affected by arterial inflow pressure
2. Renin/Angiotensin 3. Natriuretic peptide - released from heart in response to stimulation of atrial and ventricular myocytes |
|
|
Wehn is Atrial Natriuretic Peptide released and what are the effects of Atrial Natriuretic Peptide (ANP)?
|
Released in response to atrial stretch
Effects: Renal - decreases intravascular volume Vascular - smooth muscle relaxation |
|
|
Where is 40% of total blood volume located?
|
In the large systemic veins
|
|
|
Adrenergic / muscarinic stimulation lead to what wrt venous smooth muscle?
|
Adrenergic: Constriction - puts blood in central circulation, augments cardiac preload
Muscarinic: Dilation - distributes blood to large veins, reduces cardiac preload |
