Topic 10 Flashcards
local pressure drop in arterioles is greater with –
vasoconstriction
capillary flows and pressures vary from –
region to region
when – increases to match work load, flows are not uniformly increased to all organs
cardiac output
during strenuous exercise, CO to brain is –
about the same
during strenuous exercise, CO to heart increases –
3.5x
large coronary arteries on the epicardial surface divide frequently and enter the myocardium to form a –
dense capillary network
areas of – on coronary arteries are subject to turbulent flow and lesions
bifurcation
when body is resting, coronary flow is about –
4% of total flow
200-225 ml/min
there is a – ration of capillaries to cells
1:1 ratio (among highest in body)
the majority of venous return goes to the RA via the –
coronary sinus
the coronary capillary circulation is embedded in the –
contracting myocardium
– feeds the coronaries
LV
when the left ventricle contracts, the pressure in the wall is – than the perfusion pressure in the coronary vessel
the same or greater than
left coronary blood flow is greatest during –
diastole
the oxygen tension in the venous blood leaving the – is the lowest of any venous blood in the body leaving little room for additional O2 extraction to meet any increased demand from heart
coronary capillaries
How do you meet increased myocardial O2 demand?
increase blood flow
coronary flow is primarily modulated by –
metabolic factors like adenosine and NO thru ANS, hypoxia, angiotensin, vasopressin and other drugs that modify flow
there is a strong correlation between – and coronary flow
myocardial metabolism
the coronary circulation is highly – and consists of a dense capillary bed designed to adequately supply the heart with oxygen
specialized
LV coronary flow is highly dependent on – since little perfusion is possible in the LV during systole
diastolic arterial pressure
compared to LV, RV flow is more –
balanced (constant)
cerebral blood flow is relatively independent of –
MAP
what regulates cerebral blood flow?
local hyperemia and autoregulation
cerebral neurons require an adequate supply of oxygen and – at all times
glucose
though only 2% of body mass, the CNS consumes nearly – of O2 at rest and maintains no energy reserves
20%
the changes in flow regulation via – occur gradually (over minutes) and do not protect the brain from sudden changes in MAP
vascular resistance
there is – blood flow in pulp
a lot
sympathetic stimulation of vessels that supply the pulp – their blood flow
reduce (vasoconstrict innervated tissue)
stimulation via the – induces severe vasoconstriction in the vessels supplying the pulp and gingiva
cervical sympathetic chain
stimulation of the parasympathetic fibers of the glossopharyngeal nerve (#9) elicit –
vasodilation of the gingiva but not the pulp
what does not demonstrate a parasympathetic response
pulp
How do you elicit vasodilation in the pulp?
surface stimulation of tooth or gingiva mediated by sensory nerve fibers that carry the signals to the brain and back inside the pulp
what does irritation of tooth or gingiva during dental procedures result in?
increased blood flow to teeth
the flow of saliva is tightly coupled to –
blood flow
salivary glands secrete a lot of saliva (enzymatic secretions) and therefore require –
substantial blood flow
both sympathetic (minor) and parasympathetic stimulation can – but parasympathetic is more effective
increase blood flow and watery secretions
splanchnic
gut, intestine, spleen, pancreas, liver
splanchnic circulation is an example of – circulation
portal (two capillary beds in series)
visceral blood flows form the capillary beds of the stomach, intestines, spleen, pancreas, liver to –
portal vein
from the portal vein, blood then flows into – for cleansing
hepatic sinuses in liver
viscera and liver receive about 20-30% of – at rest which may drop to 3% during exercise
cardiac output
cardiac output to kidneys
20%
capillaries in kidneys are highly –
specialized
– arteries and veins in cortex of kidneys
interlobular
afferent and efferent arterioles with – capillaries are associated with the glomerulus
peritubular
what is in the medulla?
vasa recta
highly – capillaries permit high blood flows and diffusion of substances between the afferent and efferent arterioles in the glomerulus
fenestrated
– of the CO flows thru dense capillary network surrounding the alveoli
100%
pulmonary capillaries are closely packed around the alveoli to permit –
rapid gas exchange
shock exists whenever there’s a generalized – to tissues
severe reduction in blood supply
occurs when cardiac pumping ability is compromised
cardiogenic shock
cardiogenic shock can result from –
lowered CO (myocardial infarction
valvular disease
heart failure
arrhythmias)
occurs when there’s a significant fluid loss
hypovolemic shock
hypovolemic shock can result from –
hemorrhage
severe burns
chronic diarrhea
prolonged vomiting
– shock occur when vasodilators are activated
anaphylactic and septic
anaphylactic and septic shock can be due to –
severe allergic reactions or from toxins than lead to decreased venous pressures and vascular resistance
occurs when vascular tone is decreased due to a reduction in sympathetic activity
neurogenic shock
neurogenic shock can be due to –
severe anesthesia, deep pain or in a milder form with strong emotions
certain emotional events can lead to a – response
vasovagal
what tends to blunt all nerve activity particularly sympathetics?
anesthetics
anesthetics –>
HR and contractility fall while vessels vasodilate
what is the effect of anesthetics on blood pressure?
drop
many response to stress occur from numerous sources including –
adrenal glands
among the many hormones and factors released, – impact the cardiovascular system the most
catecholamines (mainly EPI) and cortisol
