Flashcards in Endocrine and neuronal regulation of blood pressure Deck (44)
What are the two ways in which blood pressure is controlled?
Short term regulation
Long term regulation
What controls short term regulation of blood pressure ?
Autonomic nervous system
What controls long term regulation of blood pressure?
What is an example of something that triggers short term control of blood pressure ?
Postural hypotension - decrease in blood pressure due to gravity to head/neck
What is an example of something that triggers long term control of blood pressure?
Increase uptake of salt/ water fue to consumption of salty food
How does the baroreflex control blood pressure?
Baroreceptors detect changes in arterial pressure
Signal is sent to the medulla of the brainstem
Vagus nerve adjusts heart rate
Sympathetic nerves adjust cardiac contractility and peripheral resistance
How does the vagus nerve adjust heart rate?
Decrease in vagal activity leads to an increase in heart rate
How do the sympathetic nerves adjust cardiac contractility and peripheral resistance?
Causes vasoconstriction of peripheral blood vessels
How do the kidneys regulate long term control of blood pressure?
Hormones act on the kidney to regulate long term control of blood pressure
How do the hormones released that act on the kidney affect long term control of blood pressure?
Affect sodium and water reabsorption
What are the three hormones that act on the kidney that regulate long-term control of blood pressure?
Atrial natriuretic peptide
What organ synthesises ANP?
What is the goal of ANP?
To decrease blood volume
How does ANP control blood pressure?
ANP binds to receptors on the DCT and collecting ducts
Interacts with NCC (sodium-chlorine cotransporter) and ENaC (epithelial sodium channel)
ANP also inhibits renin secretion - inhibits the renin-aldosterone system
What is the effect of ANP on the renin-angiotensin system?
Inhibits the renin-angiotensin system
Inhibits renin secretion
What part of the heart secretes ANP?
Cardiac atrial myocytes synthesise and store ANP
What do ventricles produce?
Brain natriuretic peptide
First isolated in the brain
Structure of ANP
28 aa peptide
17 aa ring in the middle of the molecule
What is the main goal of the renin-angiotensin system?
Increase blood pressure
What is the sensor of the renin-angiotensin system?
The juxtaglomerular apparatus
What does the juxtaglomerular apparatus control?
Concentration of solutes in the plasma
What is the juxtaglomerular apparatus made of?
Macula densa cells
Granular renin producing cells
Afferent and efferent arterioles
Which cells produce renin?
Granular renin producing cells
What are granular renin producing cells sensitive to?
Perfusion pressure - when P is low in afferent arteriole, it stimulates renin secretion
NaCl deliver to macula densa cells - when decreased, renin secretion is enhanced
What happens when delivery of NaCl to macula densa cells is decreased?
Renin secretion is enhanced
Describe the steps of renin-angiotensin system
1. Angiotensinogen is released from the liver
2. Renin is released from the kidneys, converts Angiotensinogen -> Angiotensin I
3. Angiotensin I is inactive
4. ACE releasedfrom the lungs and converts Angiotensin I -> II
What are the effects of Angiotensin II?
Can affect smooth muscle receptors
Causes release of Aldosterone from the adrenal gland
When in high concentration, can activate the release of ADH
What does Angiotensin II release when in high concentration?
What is ADH?
A small peptide