Cardiovascular regulation

Question 1

Describe the response of baroreceptor to changing MAP (mean arterial pressure). what are the four common goals of the two pathways? Describe

Answer 1

these are Feedback or Feed forward

1. feedback
   
   1. response to intrinsic
      
      1. tonic drive:chemo, osmo, mechano receptors
      2. directly brainstem circuit
2. feedforward
   
   1. response to extrinsic
      
      1. all stimulating the forebrain and mid brain ->ventral command->lower brainstem

both have a common goal

• activate the lower brainstem
  
  1. motor outflow to respiratory muscles
     
     • alters ventilation. Directly altering pO2
  2. symptathtic tone output to vascular bed and heart
     
     • _sympathetic tone alters toal periperal resistance (TPR)_
  3. parasympathetic outflow to the heart
     
     • recall regulation of heart by ANS and smooth muscle
     • _alters cardiac output (CO) whic too alters arterial pressure_
       
       • ​**arterial pressure now acts as intrinsic input
  4. vagal outflow to the heart

Question 2

How does O2 regulation manipulate blood flow (2 reasons)

Answer 2

1. blood flow to skeletal supply modified and thus altering O2 supply
2. ulization of O2 by tissue results in hyperemic and paracrine signals to capillaries
   
   1. see lecture microciculation

Question 3

What is the drive to the central circuitry dependent on?

Answer 3

CONTEXT DEPENDENT

• the drive to the central circuitry can alter the response of the circuitry to peripheral conditions
• RSNA=renal sympathetic nerve activity
  
  • ​a procy for cardiovascular circuitry output

Question 4

diagram the regulation principles of feedback and feedforward mechanisms. ultimately what is affected?

Answer 4

1. decrease MAP
2. increase O2

know the generals about the map.

Question 5

Diagram the baroreceptor reflex: give the purpose, how its done and the goal of this reflex.

Answer 5

1. purpose
   
   1. rapid adjustment of
      
      1. arterial pressure
2. how
   
   1. brainstem circuitry
      
      1. increases sympathetic tone
      2. deccreases vagal tone
   2. increases Cardiac output
   3. increases total peripheral resistance
3. goal
   
   1. return arterial pressure to desired level

Question 6

what is the location of the baroreceptors?

Answer 6

they are neurons with dendritic arbors in the

1. carotid sinus
2. aortic arch

construct

1. pseudo-monopolar sensory neurons with soma in the
   
   1. pteygopaltine ganglion (IX)
   2. nodose ganglion(X)

operation

1. SAC -specifically TRPC5-transient receptor potential channel 5
   
   1. ​they fire tonically with every heart beat
   2. their rate of fire is correlated with MAP

Question 7

What is correlated with MAP? What is it tonically synced with?

Answer 7

the baroreceptors rate of firing is corelated with MAP (increase and decrease is linear)

They are tonically synced with heart rate.

Question 8

diagram the baroreceptor circuitry (not the reflex ). What is their role in MAP?

Answer 8

NTS-nucleus tractus solitarius

NA-nucleus ambiguus

CVLM-caudal ventrolateral medulla

RVLMrostral ventrolateral medulla

with in each there are interneurons and differing population of efferents

1. MAP
   
   1. MAP increase recruits neurons that directly or indirectly excite NA and CVLMefferents directly or indirectly
   2. CVLM-effeerents inhibit RVLM effernts . Directly and indirectly
   3. RVLM - recruit sympathetic preganglionic neurons
      
      1. under this inhibitory situation, sympathetic tone is reduced
   4. NA-contain preganglionic PSNS neurons that are excited when MAP increases.
      
      1. this increases parasympathetic tone
2. consequence= decrease in cardiac output

Question 9

Draw the CNS circuitry integrating endocrine and ANSresponse to dehydration. Explain the structures and locations. What is the goal of this pathway?

Answer 9

1. decrease in MAP->renal renin release->angiotensin 2 activity
2. osmolarity and angiotensin 2 detected in two locations of circumventricular organs
   
   1. subfornical organ(SFO)
   2. oranum vasculosum lamina terminalis (OVLT)
   3. CVO structures are highly vascular and permeable, unlike the othe location in the BBB
3. SFO and OVLT project into the following locations of the hypothalamus
   
   1. paraventricular organ(PVN)
   2. median preoptic nucleus(MnPO)
   3. supraoptic nucleus(SON)
4. products of the hypothalamus
   
   1. ADH form the
      
      1. PVN and SON
      2. increases water reabsorption and increaed sympathetic tone increases MAP(depending on dehydration level, to or toward compensation to drop) , while decreasing blood osmolarity
5. goal is to decrease blood osmolarity, increase MAP, increase CO and increase TPR
   
   1. this pathway decreases when blood osmolarity returns to normal

Question 10

diagram the circuitry involved in defensive behavior. list the functions of the organs

Answer 10

1. note the stimulus
   
   1. NOISE
2. thalamus
   
   1. interacts with the cortex in processing the noise
3. amygdala
   
   1. adds emotional color to the stimulus
4. hypothalamus
   
   1. releases corticotropin releasing hormone CRH
      
      1. increases ventilations
   2. activates brainstem circuitry
      
      1. increases sympathetic tone
5. midbrain
   
   1. activates brainstem circuitry that freezes the subject
6. 1. 1. decreases parasympathetic tone

Question 11

How does an increase in pressure affect the baroreceptors?

Answer 11

increasing pressure->activates the SAC-> higher the pressure the larger the response (more AP by the baroreceptors)

Question 12

what changes the tonic drive?

Answer 12

intrinsic inputs

Question 13

what are the principals of feedback?

Answer 13

sensors supply the tonic drive

• these are intrinsic receptors
  
  • chemo-, osmo-, mechano-

feedbach mode operates directly on brainstem circuits

Question 14

lower brain stem involves regulation of heart and respiratory muscles

Answer 14

changes the partial pressure of O2

• results in change in O2 concentration in tissue
• increasing hyperimc factors in the tissue, changing the enviornment. hyperimic factors regulate the blood flow based on local metabolic activity.
  
  • Po2
    
    • reduction
      
      • leads to increase in
        
        • adenosine, prostaglandin, and NO
  • Pco2
  • pH
  • K+
  • lactic acid
    
    • increase
      
      • leads to increase in NO
      • reduces Ca intracellularly
  • ATP
  • ADP
  • adenosine

Question 15

What alters total peripheral resistance? What about cardiac output?

Answer 15

• sympathetic tone
  
  • altering the arterial pressure
• parasympathetic and sympathetic
  
  • both alter cardiac output
    
    • making a cotribution to the arterial pressure

Question 16

standing up really fast affects pressure in the ___. what compensates this hypotension?

Answer 16

standing up rapidly leads to hypotension in the aorta

reduced firing by baroreceptor:

1. increase arterial pressure
   
   1. increase cardiac output
      
      1. heart rate increase
      2. increase cardiac contractility
   2. increase vascular resistance

Question 17

What happens to the blood volume during dehydration?

Answer 17

decrease in blood volume

• leads to decrease of arterial pressure

Question 18

what is more serious dilution of sulutes or concentration of solutes?

Answer 18

Dilution

• b/c you want to conserve your salts

Question 19

what cells are ADH releasing cells? What is the function of ADH?

Answer 19

PVN and SON

ADH acts to increase reabsorption of water in kidneys_> restoring fluid balance-> increaseing arterial pressure** and **DECREASING osmolarity

Question 20

What stimulates the release of ADH?

Answer 20

1. hypotension
2. high osmolarity

Question 21

PVN has an extension to the brain that regulates____

Answer 21

1. total preipheral reisstance
2. cardiac output

Question 22

how does sympathetic tone affect MAP and osmolarity?

Answer 22

1. decrease blood osmolarity
2. increase MAP

Question 23

barareceptor reflex activates to stimulate ANS and acts on what?

Answer 23

CVLM inhibits RVLM, with no baroreceptors firing the