Cardiac Output, Blood flow, BP #2 Flashcards
Myoglobin in the myocardium stores O2 during ____ and releases it during ______
diastole, systole
T/F the heart always respires aerobically
True
How is increased oxygen requirements met in the heart?
corresponding increase in coronary blood flow
What do coronary arterioles contain that promote vasoconstriction and vasodilation
alpha/beta andrenergic receptors
norepinephrine stimulates what receptors to promote what action in the heart?
alpha adrenergic, vasoconstriction
epinephrine stimulates what receptors to promote what action in the heart?
beta adrenergic, vasodilation
How to diagnose coronary artery disease?
coronary angiogram
Why do you have to insert a stent during an angiogram?
to prevent restenosis
If a stent was not effective for coronary artery disease what could you do?
coronary bypass grafting
What causes vasodilation and decreased resistance of coronary circulation during exercise?
sympathoadrenal system and intrinsic metabolic changes
How does exercise training affect coronary arterioles?
increases density coronary arterioles , decreases compression of coronary vessels in systole and increases production of nitric oxide
What is increased by increased contractility from sympathoadrenal stimulation
ejection fraction
How does endurance training effect cardiac rate and stroke volume?
lowers cardiac rate and increases resting stroke volume
cerebral blood flow is regulate by _____ and is relatively_____ while cutaneous blood flow is regulated by _____ and is relatively ______
intrinsic, constant, extrinsic, variable
what functions together to promote neurovascular coupling?
neurons, astrocytes and arterioles
active neurons receive more oxygen and glucose for their increased needs?
functional hyperemia
cerebral blood flow is regulated almost exclusively by
local intrinsic mechanism (autoregulation)
What happens to end diastolic volume during exercise and why?
it does not decreae because venous return is aided by improved movement of skeletal and respiratory pumps
What regulates variation in systemic arterial pressure?
myogenic regulation
How does hypoventilation affect cerebral arteries?
they dilate as CO2 rises
Total cerebral blood flow is _____ but the distribution is ______
constant, variable
brain regions with the highest _______ receive the most blood flow
metabolic activity
What test monitors distribution of cerebral blood flow?
positron emission tomography
What vessels are found mostly in fingertips, palms, toes, soles, ears, nose and lips and what function do they perform?
arteriovenous anastomoses, shunt blood directly from arterioles to deep venules
Why does skin appear rosy despite reduced cutaneous blood flow in cold weather?
blood is diverted to superficial capillary loops
When blood flow to skin is so severely restricted because of the cold that tissue dies
frostbite
What stimulates cutanous vasoconstriction and vasodilation?
sympathetic nerves
What do sweat galnds secrete to stimulate vasodilation?
bradykin (a polypeptide)
During exercise, cutaneous vessels are _____ and exercising muscle vessels are ______
dilated, dilated
low total peripheral resistance and a fall in cardiac output post exercise can lead to ?
fainting, loss of consciousness
What are the most important variables affecting blood pressure?
cardiac rate, stroke volume (determined by blood volume) and total peripheral resistance
What two things regulate blood pressure?
kidneys and sympathoadrenal system
Where are baroceptors located and what kind of receptors are they?
stretch receptors, aortic arch and carotid sinuses
What cranial nerves are involved with baroceptors and where do these nerves report?
vagus (X) and glossopharangeal (IX), medulla oblongata
What center regulates total peripheral resistance and what center regulates cardiac rate?
vasomotor control center, cardiac control center
What are the effectors of the baroceptor reflex?
sympathetic axons to the heart and blood vessels
What regulates blood pressure long term?
the kidneys via blood volume regulation
How can one reduce tachycardia manually?
massage the carotid sinus
Low BP when standing
orthostatic (postural) hypotension
IN elederly people BP falls after eating
postpranadial hypotension
killled elvis
cardiac arryhthmia from barbituates, reduced HR, increased thoracic pressure, valsalva maneuver
When is the brachial artery quiet?
before bp cuff is inflated or if the bp cuff is too tight and cuts off blood supply (about 140 mm pressure)
When blood flows smoothly and doesn’t produce vibration
laminar flow
When blood flow causes vibrations or sounds
turbulent flow
sounds heard when taking bp
korotkoff sounds
When is the first korotkoff sound heard
When cuff pressure is equal to systolic pressure
the difference between diastolic and systolic pressure
pulse pressure
Hypertension as a result of a disease
secondary hypertension
What is the most common type of hypertension?
primary (essential) hypertension
What dietary habit can increase bp and how?
high salt intake, increased plasma osmolality thus adh secretion
What 2 hormones affect bp the most?
antidiuretic hormone and aldosterone
What is the “final common pathway” in essential hypertension?
kidney function
how does dietary potassium influence salt intake and hypertension?
higher potassium levels can reduce the ability of salt to cause hypertension
What disorder is characterized by thrombocytopenia an proteinuria
preeclampsia (toxemia of pregnancy)
What medication can decrease hypertension by influencing blood volume?
diuretic
What medication lowers cardiac rate to decrease BP?
beta adrenergic receptor blockers (like atenolol)
What drugs reduce vasoconstriction to treat high bp?
Angiotensis converting enzyme inhibitors (ACE)and angiotension II receptor blockers (ARB)
What drug blocks the production of aldosterone
angiotension II receptor blockers
circulatory shock due to low blood volume
hypovolemic shock
Causes of hypovolemic shock
hemorrhage, dehydration, burns
When entering hypovolemic shock, decreased BP and cardiac output leads to what?
activation of baroceptor reflex–> tachycardia and vasoconstriction
Decreased blood flow through kidneys stimulates what?
renin secretion and activation of the renin angiotension aldosterone system
Symptoms of hypovolemic shock
low bp, rapid pulse, cold clammy skin, reduced urine output
What can commonly cause septic shock
endotoxin or gram negative shock
What does endotoxin activate to produce a fall in BP?
nitric oxide synthase
anaphylactic shock from an allergic reaction results from
widespread release of histamine
upper spinal cord damage or spinal anesthesia can lead to
neurogenic shock
cardiac failure leads to what kind of shock?
cardiogenic shock
Common causes of left ventricular heart failure
myocardial infarction, aortic valve stenosis and incompetence of the aortic and mitral valves
How does excessive potassium affect the heart?
decreases resting membrane potential of myocardial cells and cause heart to stop in diastole
How does high calcium affect the heart?
increases excitation, arrests heart in systole
Why do we use the word congestive with heart failure?
failure of the ventricles increases venous volume and pressure, and causes edema in their respective destinations (systemic or pulmonary)
Compensatory responses of CHF are similar to what?
hypovolemic shock
Low blood pressure usually leads to syncope so that gravity can bring blood to the brain, but what happens if the body remains upright?
telephone booth syncope, cardiac arrest
Researchers found women with preeclampsia were more likely to have what in their bloodstreams?
intact fetal cells
Stress induced heart failure
Takotsubo cardiomyopathy, broken heart syndrome
