1.12 - Anatomy And Physiology Flashcards
What is RAAS
Renin Angiotensin Aldosterone System
Normal physiological control of blood pressure
Where is renin released from
Juxtaglomerular apparatus
What triggers renin release
Reduced sodium delivery in DCT, detected by macula densa cells
Reduced perfusion pressure in kidney, detected by baroreceptors in afferent arteriole
Sympathetic stimulation of JGA by beta-1-adrenoreceptors
What inhibits renin release
Atrial natiuretic peptide (ANP)
Released by stretched atria in response to increased blood pressure
Negative feedback loop
Where is angiotensin produced and released
Liver
How is angiotensin activated
Cleaved by renin to form angiotensin I
Angiotensin I is activated in the lungs by ACE -> Angiotensin II (active form)
What receptors does Angiontensin II bind to
AT1 and AT2
What are the actions of angiotensin II, and where do they occur
Arterioles - vasoconstriction
Kidneys - increase sodium resorption
SNS - increase noradrenaline release
Adrenal cortex - stimulates aldosterone release
Hypothalamus - increased thirst sensation - stimulates ADH release
Where is aldosterone released
From the adrenal cortex in response to angiotensin II
What is aldosterone
Steroid hormone released by zonal glomerulosa of the adrenal cortex
What is the action of aldosterone
Increases expression of ENaC receptors in collecting ducts -> increase sodium resorption
Increases basolateral Na/K/ATPase activity -> increase sodium resorption
Increase in sodium resorption -> increase blood volume -> increase BP
also leads to decrease in serum potassium
What artery supplies the eye
Ophthalmic artery - branch of internal carotid
Main branch is central retinal branch - occlusion causes rapid onset blindness
What is the venous drainage of the eye
Superior and inferior ophthalmic veins -> cavernous sinus
What causes glaucoma
Drainage of aqueous humour from anterior and posterior chambers
What causes cataracts
Clouding / opacity of lens
What causes hypertensive retinopathy
Vasoconstriction of retinal blood vessels, endothelial damage, or necrosis due to prolonged hypertension
What is the order of branching of renal arteries
Renal artery
Posterior and anterior divisions
Segmental arteries (5 each)
Interlobar arteries
Arcuate arteries
Interlobular arteries
Afferent arteriole
Efferent arteriole
What is the venous drainage of the kidney
Renal veins -> IVC
Where do the renal arteries originate
Abdominal aorta, immediately distal to superior mesenteric artery
Which arteries are in the anterior circulation of the circle of Willis
Anterior cerebral arteries
Anterior communicating artery
Middle cerebral arteries
What arteries are in the posterior circulation of the circle of Willis
Posterior cerebral arteries
Posterior communicating arteries
What is the function of the anterior communicating artery
Connects the anterior cerebral arteries
What do the anterior cerebral arteries supply
Midline of frontal lobe and superior part of parietal lobe
What is the function of the posterior communicating arteries
Connects internal carotid and posterior cerebral arteries
What are the posterior cerebral arteries formed from
Terminal branches of basilar artery
What is the basilar artery formed from
Union of vertebral arteries
