neurohumoral control Flashcards
Which sympathetic nerve receptor predominantly causes vasoconstriction?
alpha
Which sympathetic nerve receptor predominantly causes increased contractility?
beta 1
Which sympathetic nerve receptor predominantly causes bronchodilation?
beta 2
Chronotrophy
HR
inotropy
contractility
dromotropy
conduction velocity
lusitropy
relaxation
What is the “second messenger” that is involved with sympathetic stimulation of a cardiac muscle cell?
cyclic AMP
Which catecholamine does the adrenal gland predominantly release with sympathetic stimulation?
Mostly epinephrine (80%), lesser amount norepinephrine (20%)
What is the Baroreceptor Reflex
Sensor of change in BP, increases or decreases HR due to change. Located in carotid sinus and aortic arch
Where are the receptors for the baroreceptor reflex located?
Located in Carotid SINUS and Aortic Arch
How does the Baroreceptor Reflex help with blood pressure regulation?
Helps ↓ daily variation in blood pressure
Helps with postural changes in BP
Responds rapidly to changing pressure
During what surgery does Baroreceptor Reflex activation frequently cause hemodynamic changes?
Carotid endarectomy
What is the Bainbridge Reflex?
Infusion of ↑ VOLUME causes ↑ HR due to activation of atrial stretch receptors
Where are the receptors for bainbridge reflex located?
Vena cava – right atrial junction
Pulmonary vein – left atrial junction
In addition to receptor activation what also contributes to the heart rate changes seen with the Bainbridge Reflex?
Stretch of heart and stretch of SA node
The Baroreceptor Reflex responds to changes in arterial blood pressure or to changes in blood volume?
pressure
The Bainbridge Reflex responds to changes in arterial blood pressure or to changes in blood volume?
volume
What are some of the effects of Atrial Stretch Receptor activation?
↓ Volume by ↑ Urine output and ↓ BP
↑HR (Bainbridge)
What is the Bezold-Jarisch Reflex?
strong contraction of an undefiled ventricle => ↓HR, BP, and SVR
What is the CNS ischemic response?
Atrial pressure elevation in response to cerebral ischemia
What is the Cushing Response?
Increased ICP causes increased BP until blood flows once again in the vessels of the brain
What is Cushing’s Triad?
Irregular respirations (caused by impaired brainstem function), bradycardia, and widening pulse pressure (caused by systolic hypertension).
Under what circumstances can Peripheral Chemoreceptors cause hemodynamic changes
When SBP< 80mmHg => ↓PaO2, ↑PaCO2, ↓pH => excites vasomotor center in medulla => ↑ SVR and MAP
What is the Diving Reflex?
the body’s physiological response to submersion in cold water and includes selectively shutting down parts of the body in order to conserve energy for survival.
Vasopressin is released from which part of the brain? What are the effects of vasopressin on blood pressure? What are the effects of vasopressin on the kidney?
- Vasopressin is released from the hypothalamus. Increases BP. Greatly increases water reabsorption from the renal tubules back into the blood and therefore helps to control body fluid volume. (antidiuretic hormone)
What is the stimulus for release of Atrial Natriuretic Peptide?
ANP is released by the atrial walls of the heart when they are stretched
What are the effects of ANP on blood pressure?
The ANP has a direct effect on the kidneys to increase greatly their excretion of salt and water. Therefore, ANP plays a natural role to help prevent extreme congestive systems during cardiac failure. Causes Decreased BP
What converts angiotensinogen to angiotensin I?
renin
What converts angiotensin I to angiotensin II?
- Angiotension-converting enzyme (ACE). Located in the lungs
What are the INDIRECT effects of hypoxia on the circulatory system?
SNS activation. Increased HR, Increased CO, increased contractility.
What are the DIRECT effects of hypoxia
Depressed myocardial contractility
What are the INDIRECT effects of hypercarbia on the circulatory system
SNS activation. Increased HR, Increased CO, increased contractility. \
what are the direct effects of hypercarbia
depressed myocardial contractility
