regulation 4 Flashcards
Humoral control of the vasculature
- Renin-Angiotensin-Aldosterone
2. Atrial Natriuretic Peptide
What is the Primary system for long-term control of blood pressure?
Renin-Angiotensin-Aldosterone system
renin release is stimulated by
sympathetic stimulation, decreased blood pressure in renal artery, and decreased Na+ reabsorption
angiotensin converting enzyme (ACE) function
cleaves angiotensin I to Angiotensin II (AII)
A2 is a
vasoconstrictor
ACE inhibitors & Angiotensin II receptor blockers = Therapeutics for treatment of
hypertension & heart failure
direct effects of AII (A2)
systemic vasoconstriction via binding to GPCRs on VSMCs.
indirect effects of AII (A2)
Stimulates sympathetic activity and release of aldosterone, endothelin, and ADH
aldosterone is a
steroid hormone produced by the adrenal cortex
aldosterone functions to
- promote reabsorption of Na and water in the kidney collecting duct
- increased blood volume and blood pressure
anti-diuretic hormones are
- ADH
- arginine vasopressin
they are peptide hormones
anti-diuretic hormones are formed in the
hypothalamus and released by pituitary
anti-diuretic hormones release is stimulated by
- hypovolemia
- hypotension
- high osmolaroty
- angiotensin II
- sympathetic stimulation
anti-diuretic hormones functions
- Increases water reabsorption in kidney
2. Can also bind to receptors in vasculature to cause vasoconstriction.
Atrial Natriuretic Peptide is released by the
atria (mostly right) in response to stretch
ANP functions
- Long-term regulation of Na+ and water balance
2. increases glomerular filtration rate and secretion of Na+ and water (natriuresis and diuresis).
ANP mechanism
- ANP binds to Natriuretic Peptide Receptors
2. Receptor guanylate cyclases (not GPCRs), produce cGMP
natriuretic means
sodium excretion
Integrated Responses of the Cardiovascular System
- Gravity
- Exercise
- Hemorrhage
Immediate Effects of Standing
- Right atrial pressure drops
- Venous pressure in legs increases
- Blood pools in veins
Secondary Effects of Standing
Increased capillary hydrostatic pressure (Pc) causes:
1. net capillary filtration
2. increased interstitial fluid
3. decreased blood volume
(which leads to decreased mean arterial pressure)
What decreases with age?
- Spontaneous AP firing rate in Sinoatrial Myocytes
- max heart rate
- intrinsic hr
why do vasoactive metabolites result in increased extracellular K+?
Na+/K+-ATPase can’t keep up, so K+ accumulates in interstitial space
What is a counter part to adenylate cyclase?
Phosphodiesterases
HCN functions
Promotes excitability and spontaneous action potentials
HCN expressed in
Highly expressed in sinoatrial myocytes
HCN activity increased by
sympathetic stimulation via cAMP binding
NCX serve to
remove Ca2+ from cytoplasm
NCX promote
excitability and spontaneous action potentials
