Autonomic control of the nervous system Flashcards
(16 cards)
ANS in the urinary system
The ANS consists of the sympathetic and parasympathetic divisions, which play a crucial role in controlling kidney function and urine formation, storage and elimination processes
SNS in the urinary system
The SNS is activated during stressful situations or when blood pressure drops, triggering the fight-or-flight response
What hormone does the SNS release? And what does it do?
The SNS releases norepinephrine, which causes vasoconstriction of the afferent arterioles. This reduces blood flow to the glomerulus, therefore decreasing the GFR.
SNS ____ blood pressure to ____
PNS ____ blood pressure to ____
Increases, normal
Decreases, normal
What is the RAAS?
The Renin Angiotensin Aldosterone System (RAAS) is a hormone system that regulates blood pressure and fluid balance, crucial for maintaining systemic vascular resistance.
The first key component of the RAAS
Renin is an enzyme released by the kidneys in response to low blood pressure or reduced sodium levels.
The second key component of the RAAS
Angiotensin is a protein produced by the liver that is converted to angiotensin I by renin.
The third key component of the RAAS
Angiotensin-converting enzyme (ACE) is an enzyme produced by the lungs that converts angiotensin I to the active hormone angiotensin II.
What does angiotensin II do?
Angiotensin II causes vasoconstriction, stimulates aldosterone and ADH release, and increases SNS activity, all contributing to elevated blood pressure.
PNS in the urinary system
The PNS plays a role in regulating renal blood flow and function
What hormone does the PNS release?
And what does it do?
The PNS releases acetylcholine, which acts on receptors in the smooth muscle cells of the renal blood vessels, causing vasodilation. The vasodilation then leads to an increase in blood flow to the glomerulus, which in turn leads to an increase in GFR.
Explain the relationship between the SNS and the detrusor muscle
The SNS controls the detrusor muscle to relax, which promotes bladder storage and contracts the internal sphincter, preventing urination during high periods of stress and activity.
Explain the SNS coordination with PNS
During bladder filling, the SNS inhibits the parasympathetic signals that would cause bladder contraction.
What does the PNS promote?
Urination
How does the PNS promote urination?
It stimulates the detrusor muscle to contract, allowing urine to be expelled. It relaxes the internal sphincter so the urine can pass from the bladder to the urethra.
Explain how a spinal cord injury affects bladder function
The communication pathway between the brain and bladder through the spinal cord is disrupted which impairs the bladders function.
