Reflex control of circulation Flashcards

1
Q

What does short-term (extrinsic) control include?

A

– neural reflexes
– hormonal mechanisms

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2
Q

What does short-term local control include?

A

– biomechanical
– humoral
– metabolic
– neural

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3
Q

What does long-term control include?

A

– blood volume (kidney!)
– vascular remodeling

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4
Q

What does respiratory system include?

A

peripheral and central interactions

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5
Q

Make a Flow chart describing the baroreflex.

A

NTS: nucleus tractus solitarii SNS, PNS: sympathetic & parasympathetic nervous system

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6
Q

Make a Schematic sagittal view of the medulla oblongata depicting neural pathways involved in neurogenic hypertension.

A
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7
Q

What happens, when we suddenly stand up and get dizzy for a moment?

A
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8
Q

What is Bainbridge reflex

A

The tachycardia caused by increased venous return

-> Bainbridge found that infusing blood or saline into the animal increased heart rate.
-> This phenomenon occurred even if arterial blood pressure did not increase. He further observed that heart rate increased when venous pressure rose high enough to distend the right atrium, but denervation of the vagi to the heart eliminated these effects.

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9
Q

How does Bainbridge reflex occur in animals?

A

increased firing of B-fibers. B-fibers send signals to the brain, which then modulates both sympathetic and parasympathetic pathways to the SA node.

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10
Q

How does Bainbridge reflex occur in human?

A

stretch of SA node

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11
Q

Make a graph for Bainbridge reflex and baroreflex

A
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12
Q

Alternating activity of sympathetic and parasympathetic influence
-> Match the nerves to appropriate graph

A
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13
Q

Respiratory sinus arrhitmia
-> What are the central interactions?

A

During inspiration a (partial) inhibition over vagal activity

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14
Q

Respiratory sinus arrhitmia
-> What are the peripheral causes?

A
  • During inspiration thoracoabdominal pump mechanism aiding venous return
  • Negative thoracal pressure keeps it back
  • Increased venous return to right atrium
  • Bainbridge reflex
  • Increased venous flow ejected to the pulmonary circulation, later returning to the left heart
  • Increased venous return increases end-diastolic volume→increased stroke volume
  • Increased stroke volume increases MABP, thus activating baroreflex
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15
Q

Respiratory sinus arrhitmia
-> One of the peripheral causes: During inspiration, what does thoracoabdominal pump mechanism do?

A

aiding venous return

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16
Q

What are the interactions between sympathetic and parasympathetic nervous system?

A

Chemoreflex

17
Q

Peripheral chemoreceptors are locater at ___ and ___

A

at the aortic arch and at the bifurcation of the carotid arteries (glomus aorticum and caroticum, aortic and carotid bodies)

18
Q

What are the primary principles for Central Nervous System Ischemic Response?

A

Monro-principle and Cushing-reflex

19
Q

What does Monro-Kellie doctrine (principle) state?

A

The sum of volumes of brain, cerebrospinal fluid (CSF) and intracerebral blood is constant.
-> An increase in one should cause a reciprocal decrease in either one or both of the remaining two.

20
Q

Cushing-reflex
-> What is the cushing triad?

A

Elevated (systolic) blood pressure Bradycardia (slow heartbeat) Tachypnoe (fast breathing

21
Q

How can Perfusion pressure ensure brain blood flow?

A

Elevated intracranial pressure
-> Hypoxia in the brainstem
-> Blood pressure elevates (sympathetic activation) to overcome pressure around the brain vasculature
-> Perfusion pressure ensures brain blood flow

22
Q

What are the possible reasons for brain edema?

A
  1. traumatic brain injury
  2. hyponatraemia (Na3<125 mM)
  3. brain tumor
  4. hemorrhage
23
Q

What are the Hormonal influences on blood pressure for short-term control?

A
  • Epinephrine (norepinephrine)
  • Circulating vasoactive substances (e.g. CGRP, SP, VIP, histamine, bradykinin, maybeAch…)
  • Angiotensin
24
Q

What are the Hormonal influences on blood pressure for long-term control?

A

Influencing blood volume
* Atrial natriuretic peptide (ANP)
* Antidiuretic hormone, a.k.a. (arginine) vasopressin (ADH or AVP)
* Renin-angiotensin- aldosterone system (RAS)

25
Q

Volumenreceptors in the cardiovascular system
-> What are the short-term effect?

A

1.Increased heart rate *Bainbridge-reflex:increase heart rate
*SA strech induces increased heart rate 2.Periferial vasodilation
*Inhibition of vasoconstrictor center in the pressor zone

26
Q

Volumenreceptors in the cardiovascular system
-> What are the long-term effect?

A

-Inhibition of ADH production
-ANP (atrial natriuretic peptid)

27
Q

Cardiopulmonary reflexes
-> What are the receptors?

A

v. cava, v. pulmonalis before entering to atria, both atria, a. pulmonalis (Low-pressure receptors)

28
Q

Cardiopulmonary reflexes
-> What is the afferentation?

A

n. vagus

29
Q

Make a diagram representing Control of cardiac output

A
30
Q

4 factors for the Control of heart rate?

A
  • Neural centers
  • Neuralreflexes
  • Chemical control
  • Physical control
31
Q

Control of heart rate
-> What do neural reflexes include?

A

– Baroreflex
– Bainbridge reflex
– RSA
– Chemoreflex

32
Q

Control of heart rate
-> What does chemical control include?

A

– Blood gases
– NE, E, Thyroid hormones, glucocorticoids

33
Q

Control of heart rate
-> What does physical control include?

A

Heat

34
Q

What does intrinsic regulation for the control of stroke volume?

A

– Heterometric regulation: preload, afterload
– Homeometric regulation: contractility, rate induced regulation

35
Q

Can the cardiac muscle be tetanized?

A

The cardiac muscle cannot be tetanized

36
Q

What is Postextrasystolic potentiation (PESP)?

A

Postextrasystolic potentiation (PESP), the increase in contractility that follows an extrasystole

37
Q

Make a graph for Relationship between stroke volume and heart rate

A
38
Q

Make a graph for Relationship between cardiac output and heart rate

A