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A&P2 Lecture 2 part 3- circulatory regulation.

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winniesmith1's version from 2017-03-12 14:12

Section 1

Question Answer
What controls blood pressure and blood flowInterconnected negative feedback systems. By adjusting heart rate, stroke volume, systemic vascular resistance, and blood volume.
What does circulatory regulation doChanges blood flow to a specific area. 1. At an appropriate time. 2. In the right area. 3. Without changing blood flow to vital organs
How does autoregulation affect circulatory regulationcauses immediate, localized homeostatic adjustments
How do neural mechanisms affect circulatory regulationrespond quickly to changes at specific sites
How do the endocrine mechanisms affect circulatory regulationdirect long-term changes.
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Section 2

Question Answer
What is autoregulationAbility of tissue to automatically adjust its blood flow to match metabolic demands (ex. demand for 02 and nutrients can rise tenfold during exercise in heart and skeletal muscles). Occurs in the absence of neural and hormonal influences
What are the 2 types of stimuli that cause autoregulation1. Physical – temperature changes, myogenic response 2. Vasodilating and vasoconstricting chemicals alter blood vessel diameter
When does (vascular) autoregulation occuronly within certain pressure limits. If pressure drops too low or soars too high, autoregulation fails and organ perfusion is compromised.
What is the difference between pulmonary and systemic circulation in autoregulatory responseSystemic blood vessel walls dilate in response to low O2 to increase O2 delivery. Walls of pulmonary blood vessels constrict under low O2 to ensure most blood flows to better ventilated areas of lung
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Section 3

Question Answer
Where is the cardiovascular centre locatedin the medulla
(SNS)What does the cardio-acceleratory centre doincreases cardiac output
(SNS)What does the cardio-inhibitory centre dodecreases cardiac output
(SNS)What does the vasomotor centre doadjusts the size of arterioles.
Neural: What does the cardiovascular centre monitorarterial BP
What 2 neural mechanisms help monitor arterial BP-Baroreceptor reflexes: Respond rapidly to changed in BP. and Chemoreceptor reflexes: respond rapidly to changes in chemical composition (pH and dissolved gases).
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Section 4

Question Answer
What are baroreceptorspressure sensitive stretch receptors (Aortic arch and Carotid arteries). Detect beat-to-beat changes in BP (message sent to CV centre in brain).
What happens to baroreceptors when there is a low BP=less strech= slower rate of impulses to CV centre. CV centre decreases parasympathetic stimulation and increases sympathetic stimulation ---> vasoconstriction and/or increased HR/stroke volume which increase cardiac output ----> increase in BP.
What are chemoreceptorsSpecialised neurons that are sensitive to increases in blood levels of arterial CO2 and O2
What are chemoreceptors locatedPeripheral receptors located close to baroreceptors of carotid sinus (carotid bodies) and aortic arch (aortic bodies). -Central chemoreceptors located in the medulla oblongata
What do chemoreceptors detecthypoxia (low O2), hypercapnia (high CO2), acidosis (high H+) and send signals to CV centre
What happens when chemoreceptors are activated CV centre increases sympathetic stimulation to arterioles and veins, producing vasoconstriction and increase in BP. Signals the inspiratory centre in the brain, results in increased ventilation (increased expiration of CO2,O2 uptake and homeostasis is restored).
Apart from neural regulation, bp is also regulated by whathormones. Thus, arterial BP regulation is primarily the result of integrated neurohumoral mechanisms.
What is the effect of hormones on cadiovascular regulationboth short and long term. Blood volume regulation -changes in blood volume alter cardiac output, thereby, blood pressure. -Vasoconstriction/Vasodilation
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