3C-Regulate Arterial BP! Flashcards
What is the relationship between CO, MAP, and TPR?
CO=MAP/TPR….or…..MAP=CO x TPR
Which pathways generally control Short Term regulation of MAP? What are the targets of these pathways?
Neural pathways!…The heart and Blood Vessels
Which pathways generally control long term MAP regulation? What are the targets of this system?
Endocrine pathways!…The kidneys and blood vessels
What are the Short term regulators? What two places are they located?
Baroreceptors! Carotid Sinus & Aortic Arch
Which CN’s carry signals from baroreceptors?
IX glossopharyngeal & X Vagus (ahhh it feels good to say those again!)
Where do the CN’s deliver the message from the baroreceptors?
The brainstem—MEDULLARY CARDIOVASCULAR CENTER
What type of response does the medullary cardiovascular center employ to control hyper and hypotension?
SymNS and ParasymNS
What are the three steps taken by the medullary cardiovascular center to in response to LOW BP?(opposite steps for response to high BP)
1.Increase SymNS cardiac nerve activity 2.Increase SymNS vasoconstrictor nerve activity 3. Decrease ParasymNS
What happens after all of the neruo response to LOW BP? What are the four things affected? That increase BP back to normal? (opposite response to high BP)
VasoConstricion therefore Increased HR and SV which increases CO and TPR
What is it called when an old person gets up too fast and their baroreceptor reflex is too slow to compensate?
Orthostatic Hypotension
After a gunshot wound/acute hemmorage, what can increase the amount of blood sent back to the heart? What hormone probably causes this?
Constriction of veins increases amount of blood back to the heart! ADH! Hypovolemia is a potent stimulus for ADH secretion!
What can frequently alter the sensitivity of baroreceptors?
DISEASE!
What is the LONG term pathway for regulating blood pressure??
RAA Pathway (Renin, Angiotensin, Aldosterone)
What do the kidneys secrete in response to decrease in blood pressure?
Renin!!
What does Renin catalyze?
The conversion of Angiotensinogen to Angiotensin I in the plasma
What converts Angiotensin I to Angiotensin II?
Angiotensin Converting Enzyme (ACE)
What are the 4 effects of Angiotensin II?
1.Secrete ALDOSTERONE from adrenal cortex(salt/water retention) 2.DIRECTLY on the kidney for water/salt retention 3.VERY potent VASOCONSTRICOR 4.Brain for ADH release and THIRST
Where is Vasopressin/ADH secreted?
Posterior Pituitary
What is the MOST IMPORTANT physiologic stimulus for increasing ADH secretion?
Increased plasma osmolarity ( increased solute concentration in blood)…EAT SALT IN MOVIE THEATRE!
What are the two modes of action for vasopressin/ADH to increase BP back to normal? What receptors are involved?
- Increases Water reabsorption in the KIDNEYS VIA V2 Receptors 2. Potent Vasoconstriction VIA V1 receptors on the arterioles
What hormone is used to LOWER blood volume and therefore Blood Pressure?
ANP! Anti Natri-uretic Peptide
Where is ANP secreted and how does it work (2 ways)?
AntiNatriuretic Peptide is secreted by the ATRIA of the heart….. causes 1. EXCRETION of Sodium and Water 2.VasoDilation
What are the two hormonal regulations for increased BP?
- Increase ANP 2.Decrease ADH
What 2 things work together to promote venous blood flow in the legs and to prevent vericose veins?
1.The Skeletal Muscle Pump 2.Venous Valves
