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A&P 2 - E1 - P4
A&P 2 - Exam 1 - Part 4 - Physiology, Blood Pressure
Question | Answer |
---|---|
Blood flows because a ________________ exists between different parts of its bed. | pressure gradient |
The pressure gradient of blood flow is based on _________________. | Newton's first and second laws of motion |
Blood circulates from the left ventricle to the right atrium of the heart because a _______________ exists between these two structures. | blood pressure gradient |
What is the symbol used to stand for a pressure gradient? | P1-P2 |
P1 represents the ____________ pressure and P2 represents the ____________ pressure. | higher, lower |
The primary determinant of arterial blood pressure is the _______________ of blood in the arteries. | volume |
A direct relationship exists between arterial blood volume and ____________. | arterial pressure |
What does CO stand for? | cardiac output |
What is cardiac output determined by? | stroke volume and heart rate |
What is volume pumped per heartbeat? | stroke volume |
What does SV stand for? | stroke volume |
CO = _______ * _________ | SV, HR |
CO is computed by ___________ formula. | Fick's |
Anything that changes either heart rate or stroke volume also tends to change CO, arterial blood volume, and blood pressure in ___________. | the same direction |
What law influences stroke volume? | Starling's |
Starling's law: Within limits, the longer, or more stretched, the heart fibers at the beginning of contraction, the _____________ the contraction. | stronger |
Starling's law: The amount of blood in the heart at the end of _________ determines the amount of _________ placed on the heart fibers. | diastole, stretch |
The ______________ node normally initiates each heartbeat; however various factors can and do change the ___________ of the heartbeat. | sinoatrial node, rate |
Where are aortic baroreceptors located? | aorta |
Where are carotid baroreceptors located? | carotid sinus |
Baroreceptors affect the __________ and therefore parasympathetic and sympathetic outflow to aid in control of ______________. | autonomic cardiac control center, blood pressure |
The carotid sinus is located at the beginning of the _____________. | internal carotid artery |
Sensory fibers from __________ run through the carotid sinus nerve and the ___________ nerve to the cardiac control center. | carotid sinus baroreceptors, glossopharyngeal |
____________ impulses leave the cardiac control center and travel through the ____________ to reach the sinoatrial node. | parasympathetic, vagus nerve |
Aortic reflex: sensory fibers extend from _____________ in the wall of the arch of the aorta through the _________ nerve and the ___________ nerve to terminate in the ______________. | baroreceptors, aortic, vagus, cardiac control center |
Reflexive increases in heart rate often result from increased _____________ stimulation of the heart. | sympathetic |
Anxiety, fear and anger ___________ heart rate. | increase |
Grief _____________ heart rate. | decreases |
Emotions produce changes in heart rate through the influence of impulses from the __________ via the ____________. | cerebrum, hypothalamus |
Exercise normally ___________ heart rate. | increases |
Increased blood temperature or stimulation of skin heat receptors __________ heart rate. | increases |
Decreased blood temperature or stimulation of skin cold receptors ___________ heart rate. | decreases |
What is the resistance to blood flow imposed by the force of friction between blood and the walls of its vessels? | peripheral resistance |
Peripheral resistance is the resistance to ___________ imposed by the force of friction between blood and the ___________. | blood flow, walls of its vessels |
Arterial blood pressure tends to vary ____________ with peripheral resistance. | directly |
Arterial blood pressure tends to vary directly with ____________. | peripheral resistance |
Friction is due to __________ and ___________ of arterioles and capillaries | viscosity, small diameter |
The muscular coat of arterioles allows them to _________ or _________ and change the amount of resistance to blood flow. | constrict, dialate |
_____________ helps determine arterial pressure by controlling the amount of blood that runs from the arteries to the arterioles. | peripheral resistance |
_________ resistance and __________ arteriole runoff leads to __________ arterial pressure. | increased, decreased, higher |
What controls changes in the diameter of aterioles? | vasomotor control mechanism |
_______________ plays a role in maintenance of the general blood pressure and in distribution of blood to areas of special need. | vasomotor control mechanism |
Vasomotor pressoreflexes: Sudden increase in arterial blood pressure stimulates aortic and carotid __________________ which results in arterioles and venules of the blood reservoirs _______________. | baroreceptors, dialating |
Vasomotor pressoreflexes: Decrease in arterial blood pressure results in stimulation of _____________ centers, causing vascular smooth muscle to _____________. | vasoconstrictor, constrict |
Vasomotor chemoreflexes: What are chemoreceptors located in aortic and carotid bodies sensitive to? | hypercapnia, hypoxia, and decreased arterial blood pH |
What acts during emergency situations when there is decreased blood flow to the medulla? | medullary ischemic reflex |
Medullary ischemic reflex causes marked arteriole and venous ____________. | constriction |
Impulses from centers in the cerebral cortex and hypothalamus are transmitted to vasomotor centers in the medulla to help control ______________. | vasoconstriction and dilation |
Impulses from centers in the ______________ and _____________ are transmitted to vasomotor centers in the ____________ to help control vasoconstriction and dilation. | cerebral cortex, hypothalamus, medulla |
Several local mechanisms produce vasodilation in localized areas; this is referred to as _____________. | reactive hyperemia |