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33 Cards in this Set

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What is the equation that describes the relationship between Cardiac output and Arterial Pressure:
MAP = CO x TPR
Heart rate is altered by what system?

stroke volume is altered by...?
Autonomic Nervous system

preload
afterload
contractility
the neural reflex system that regulates mean arterial pressure operates as a series of ? feedback loops.
Negative feedback loops
Describe the negative feedback loop of the Baroreceptor Reflex.
Detector stretches --> electrical signal
Affector neural pathway
CNS
Efferent Neural pathways
EFFECTOR
Where are High pressure arterial baroreceptors located?
Internal Carotid Artery

Aortic Arch
Where are Low pressure baroreceptors located?
atria
Action potentials generated by the carotid sinus and carotid body travel through ? nerve which joins the ? nerve and petrossal ganglion.
Sinus nerve

joins with GLOSSOPHARYNGEAL CN IX
Action potentials generated by the aortic arch and aortic body travel through the ? nerve which joins the ? bodies => inferior ganglion of the vagus
Vagus nerve (CN X)

joins Superior Laryngeal Bodies
Where does positive feedback for parasympathetic preganglionic stimulation occur at?

(baroreceptors)
Nucleus ambiguus
Where does negative feedback for sympathetic occur at?

(baroreceptors)
Vasomotor area
? receive input from afferent neural pathways and send neural projections via interneurons.
Nucleus Tractus Solitarius (NTS)
NTS sends interneurons to what 3 following areas?
excitatory interneurons to CARDIOINHIBITORY or cardiac decelerator --vagal parasympth cardiac nerves

inhibitory internurons to vasomotor area - sympathetic

inhibitory interneurons to cardioacceleratory area - sympathetic
True or False

Both Glossopharyngeal Nerve IX and Vagus Nerve X are POSITIVE stimulatory parasymp. and innervate at the Nucleus Tractus Solitarius (NTS)
True
Describe the Hypovolemia baroreceptor reflex.
decrease in circulating volume

=> decrease arterial pressure

=> decrease stretch of high pressure baroreceptor cause less AP firing

=> decrease Sinus nerve activity

=> decrease NTS activity

=> less inhibition of parasymp ---> more sympathetic nervous activation

=>decrease capillary pressure ---> osmotic reabsorption of interstitial fluid
What are the three chief determinants of oxygen consumption during contraction?
heart Rate

Afterload

Contractility
True or False

Diastolic filling (preload) contributes relatively LITTLE to oxygen consumption.
True
MVO2 is highest during?
isovolumetric contraction/rapid ejection
MVO2 is lowest during?
Late diastolic filling
When is coronary blood flow to the left ventricle is highest in ?
early diastole
is myocardial oxygen consumption substantially greater for those conditions that cause pressure overloading?
Yes it is greater
Myocardial oxygen consumption can be estimated by calculating the double product of ?
HR x Systolic BP
The arteriovenous O2 difference across the ? is the largest for any organ
coronary vascular bed
True or False

The heart is an omnivore capable of metabolising a range of substrates, including fatty acids, glucose, ketone bodies, lactate and amino acids to fulfill a continuous demand for ATP
True
Majority of ATP is produced via ? in the heart
Mitochondrial Oxidative Phosphorylation
True or False

Capillary density in the heart exceeds skeletal capillary density.
True
What is the major oxygen carrier in cardiac and skeletal muscle that facilitates O2 from sarcoplasm to mitochondria.
Myoglobin
What are the 3 methods of autoregulation?
local metabolism

endothelium-mediated vasodilation

Autonomic nervous System
? is a potent vasoconstrictor produced by the vascular endothelium that counteracts many of the actions of nitric oxide.
Endothelin-1
Endothelin-1 is released in response to ? and ? and ? to balance the effect of nitric oxide.
Shear stress

angiotensin II

Catecholamines
How does endothelin-1 mechanism work?
=> activates ET-A receptors

=>activate Phospholipase C

=>cleaving of PIP2 => IP3 + DAG

=> ca2+ release

VASOCONSTRICTION
Tonic sympathetic discharge stimulates ? receptors in the coronary arteries and produces ?
α1-adrenergic receptors

Vasoconstriction
During heavy exercise, an increase in ? coronary vasoconstriction is completely overshadowed by ? that develops as a result of an increase in myocardial metabolism.
α1-mediated coronary vasoconstriction

vasodilation
Vagal stimulation is ? but probably has little direct physiologic effect on the coronary arteries.
Vasodilatory