Neurohumoral Control of the Heart & Circulation - Quiz 10 Flashcards
Which Sympathetic Nerve Receptor predominantly causes Vasoconstriction?
Alpha-1 Receptor
Which Sympathetic Nerve Receptor predominantly causes increased Contractility?
Beta-1 Receptor
Which Sympathetic Nerve Receptor inhibits neurotransmitter release?
Alpha-2
What does stimulation of the Beta-2 Receptor cause?
Bronchodilation
Vasodilation
Uterine Relaxation
Glycogenolysis
What are the precursors to Epinephrine?
Tyrosine > Dopamine > Norepi > Epi
What is Dromotropy?
Conduction velocity of AV Node
What is Lusitropy?
Relaxation of Myocardium
What is the Major differnces bt/ the Sympathetic & Parasympathetic system?
Sympathetic: Excitatory Cardiac Effects - Innervates entire heart
Parasympathetic: Vagus Nerve - Inhibitory Cardiac Effects - Innervates Atria & SA/AV Nodes
Which Catecholamine does the Adrenal Gland mostly release w/ Sympathetic Stimulation?
Epinephrine - 80%
Norepinephrine - 20%
What is the “Second Messenger” of the Sympathetic Stimulation of heart muscle cell?
Cyclic AMP - allows greater Ca++ influx
What happens intracellularly when catecholamines bind to the Beta-Adrenergic Receptor?
Activates Adenylyl Cyclase - Converts ATP to cAMP
What happens intracellularly when catecholamines bind to the Alpha-1 Receptor?
Activates Phospholipase to increase Ca++ into vessel smooth muscle causing vasoconstriction
What is Renin and how does it work?
Enzyme secreted by Kidney
Angiotensinogen > Angiotensin I > (ACE) > Angiotensin II > (Adrenal Cortex) > Aldosterone
Sodium & Fluid Retention = ↑BP & ↑Blood Volume
What is Vasopressin?
ADH released by Posterior Pituitary - causes vasocontriction & increases blood volume by renal fluid reabsorption
What does the Atrial Natriuretic Peptide do?
Decreases SVR & CVP by decreasing release of Renin
Increases Diuresis
Decreases Blood Volume
What are the Indirect effects of Hypoxia on the Circulatory System?
Sympathetic Stimulation to ↑HR, ↑Contractility, & ↑SVR
What is the Baroreceptor Reflex?
Receptors located in Cartoid Sinus & Aortic Arch
Senses blood pressure & adjusts HR, Contractility, & SVR accordingly.
What surgery does Baroreceptor Reflex activation frequently cause hemodynamic changes?
Carotid Endarterectomy
What does the Bainbridge Reflex do?
Increased Blood Volume = Increased HR
Slow Baseline = Increase HR w/ fluid
Fast Baseline = Decreased HR w/ fluid
Where are the Atrial Stretch Receptors Located?
Vena Cava - Right Atrial Junction
Pulmonary Vein - Left Atrial Junction
What are the effects of Atrial Stretch Reflex that is not part of the Bainbridge Reflex?
Increase Urine Output
Decrease BP & Blood Volume
What is the Bezold-Jarisch Reflex?
Happens when there is a Strong Contraction of underfilled ventricle
causes Bradycrdia & Hypotension
What is the CNS Ischemic Response?
When Low BP causes low O2 & high CO2 in the Medullary Vasomotor Center resulting in increased HR, Contractility, and MAP
What is the Cushing Response?
Type of CNS Ischemic Response
Increased ICP d/t increased BP until blow flows are normal in the brain
What is Cushing’s Triad?
Increased ICP
Hypertension
Bradycardia
What is the Diving Reflex?
Activates when the face feels cold water and decreases HR & increases Vasoconstriction
Where are the Peripheral Chemoreceptors located?
Aortic & Cortoid Bodies
What do the Peripheral Chemoreceptors do?
Respiration Regulation and Increases SVR & MAP
Decreased PaO2 & Increased PCO2 excites vasomotor center d/t decreased BP
Activated when MAP < 80 mmHg
What stimulates the Atrial Natriuretic Peptide (ANP)?
Atrial Distention
Sympathethic Stimulation
Angiotensin II
Endothelin
What are the Direct effects of Hypoxia on the Circulatory System?
Profound Hypoxia causes ↓HR & ↓Contractility
What is the Indirect effect of Hypercarbia?
Sympathetic stimulation causing ↑HR, ↑Contractility, & ↑SVR
What is the Direct effect of Hypercarbia?
↓Contractility
What is the “Fight or Flight” Response?
Mass discharge of Sympathetic Nervous System
↑BP
↑Blood Glucose
↑Strength & ↑Focus
↑Coagulation
↑Metabolism
What are the 2 Types of Acetylcholine Receptors?
Muscarinic Receptor
&
Nicotinic Receptor - neuromuscular junction
How does Neostigmine work?
Anti-Cholinersterase
@ Nicotinic Receptor - Reverse muscle relaxant
@Muscarinic - Bradycardia, Bronchospams, Salivation - Give Glycopyrrolate (Robinul)
Which part of the Brainstem is the Vasomotor Center located?
Medulla
Which neurotransmitter is released between the Pre-Ganglionic & Post-Ganglionic Sympathetic fibers?
Acetylcholine
Which neurotransmitter is released between the Post-Ganglionic Sympathetic fibers & Target Site?
Norepinephrine
Which neurotransmitter is released between the Pre-Ganglionic Sympathetic Fiber & Adrenal Medulla?
Acetylcholine
Which Autonomic Nervous System innervates Blood vessels except for capillaries?
Sympathetic Nervous System
