Regulation of the arterial BP short term regulation

Regulation of the arterial BP short term regulation q Works within seconds or minutes q baroreceptor mechanism long-term regulation q Works within hours, days , weeks or years q the rennin –angiotensin. Aldosteron system

Baroreceptor mechanism Baroreceptors high pressure receptors Low pressure receptors • carotid sinus • aortic arch • Right atria • Left atria • pulmonary veins

carotid body Int carotid A Ext carotid A carotid sinus Common carotid A Aortic body Aortic arch

Mechanism of transduction AP Stretch receptor stretch activated Na channels

Reflexes initiated by stretchingh. N p o s s of the baroreceptors lo G s u g a e v r ne V NTS Medulla oblongata VMC CIC CEC parasym Symp to Sym p to p heart bl V

↑rate p o ss N. h o Gl Medulla oblongata Cardiorequlatory center & VMC ↓rate ve r e n s Vagu s n ↑rate parasy erve mp Symp n Symp chain Blood vessels

Function of the baroreceptors during changes in body posture. Standing pooling of blood in the lower extremities ↓C. O. ↓ BP ↑ C. O. ↑symp outflow. ↓ baroreceptors discharging rate

carotid sinus massage press on the carotid sinus ↑ baroreceptors discharging rate inhibition of CEC stimulation of CI. C ↓HR & ↓BP

Low-pressure receptors reflexes

Control of arterial pressure by the carotid & aortic chemoreceptors carotid body aortic bod. Y

Long-term regulation The rennin – angiotensin – aldosteron system Lets start the journey

Structure of nephron Glomerulus Bowman's capsule Distal convoluted tubules Afferent a. a Collecting duct efferent a. a Proximal convoluted tubules Juxtaglomerular apparatus Loop of Henle

Juxtaglomerular apparatus

The liver circulation Renin

In the lung 00 Angiotensin II ACE 00

Adrenal gland Adrenal cortex Z. Glomerulosa Mineralocorticoids Adrenal medulla Mainly aldosteron Z. Fasiculata glucocorticoids Z. Reticularis androgens

Mechanism of action of aldosterone Interstitial renal fluid Na water Tubular cell Na-k pump K ↑K ↓ Na Na water Tubular lumen K

kidney angiotensinogen liver Renin Angiotensin I ACE Vasoconstriction Stim. thirst center + Vasopressin ↑ BP ↑ Na and water reabsor. ↑ blood volume