Lecture #7 Cardiovascular System: Control of Blood Pressure & Flow Flashcards
What are the neurons of the cardiovascular center?
Sympathetic neurons, parasympathetic neurons, and vasomotor neurons.
Which neuron increases Heart rate and contractility?
Sympathetic Neurons
What neuron decreases heart rate?
Parasympathetic Neurons
Which neuron regulates vessel diameter and is also known as a sympathetic nerve that synapse on arteriolar smooth muscle and cause vasoconstriction?
Vasomotor Neurons
What does the cortex, limbic system, and the hypothalamus do in the cardiovascular system?
CV neurons receive input from higher brain centers
Where does the CV neurons receive input from peripheral afferent nerve fibers?
Barorecptors, chemoreceptors, and proprioceptors.
What are the output effectors that increase the frequency of nerve impulses?
Cardiac inhibitor, Cardiac accelerator, and vasomotor nerves–CV center.
What happens to the heart if the heart rate decreases?
Due to Cardiac Inhibitor
What happens to the heart rate increase and contractility?
Due to Cardiac Accelerator
What happened to the blood vessels when they are vasoconstriction?
Due to vasomotor nerves
What are the cardiovascular reflexes?
They are produced by afferent signaling of baroreceptors, chemoreceptors, proprioceptors.
Which reflexes are more important in the CV regulation?
Baroreceptors and chemoreceptors
Where is the Baroreceptors located?
High pressure baroreceptors are located in the carotid sinus and aortic arch.
What cranial nerves help with input of baroreceptors into the CV center?
Cranial nerve IX and Cranial nerve X (Glossopharyngeal & Vagus)
Where are low pressure baroreceptors located?
In the walls of the right atrium and vena cavae.
What cranial nerve is carried to the CV center with input from low pressure baroreceptors?
Cranial nerve X (Vagus)
Where are chemoreceptors located?
Located in the carotid sinus and in the walls of the ascending arota.
Where is carotid sinus receptors located at?
Reach the medulla via cranial nerve IX
Where is aortic receptors located at?
Reach the medulla via cranial nerve X
What ions does Chemoreceptors respond to?
Respond to increased hydrogen ion content, increased CO2, and reduced O2 (hypoxia)
Does chemoreceptors activate SNS or PNS and what does it lead to?
They activate the SNS which leads to an increase in heart rate, stroke volume, and vasoconstriction.
What is Catecholamines?
(NE and EPI) circulate, and bind directly to cardiac muscle fibers and to blood vessel smooth muscle cells (hormonal control of blood pressure)
What effect does catcholamines cause?
Increases in heart rate, stroke volume, and constrictions of veins and arterioles.
Arteries supplying the brain and heart have more smooth muscles and are subject to vasoconstriction by the SNS or catcholamines.
True or False
False……arteries supplying the brain and heart have little smooth muscle and are not subject to vasoconstriction by the SNS or catecholamines.
Are the arteries (vessels) regulated?
These vessels are autoregulated.
What other chemicals that increase blood pressure?
Antidiuretic hormone (ADH), Angiotensin II, and Aldosterone.
What hormone causes widespread vasoconstriction in cases of extremely low Blood Pressure?
Antidiuretic Hormone (ADH)
What hormone causes intense vasoconstriction when renal perfusion is inadequate?
Angiotensin II
What hormone causes water retention and increases blood volume?
Aldosterone
Which hormone is most powerful in vasoconstrictor and it usually acts on all arterioles simultaneously when released into the blood?
Angiotensin II
Is it high blood pressure or low blood pressure that results in the release of renin by the kidney?
Low blood pressure
Angiotensinogen converts ____into angiotensin I, and the lungs convert AT I into _______by angiotensin converting enzyme (ACE) which is located in the ________cells of the lung
Renin, AT II, Endothelial
What is aldosterone?
Angiotensin regulates Aldersterone secretion—–Elevated AT II levels —-> aldosterone secretion by the adrenal cortex
What happens in aldosterone?
Increases salt and water reabsorption and raises blood pressure by raising blood volume
What chemicals decrease blood pressure?
Atrial natriuretic peptide, and Histamine.
Released by cells of the atria when blood pressure is high is called?
Atrial natriuretic peptide
What does ANP cause?
Causes vasodilation and promotes loss of water and salt by the kidneys—reducing blood volume & vasoconstriction
Released by mast cells causes vasodilation by relaxing blood vessel smooth muscle is called what?
Histamine
What is histamine role play?
Increasing blood flow to inflamed or damaged tissue.
The level of tissue metabolic activity is called?
Major regulator factor
Metabolic or “_______” is blood vessel dilation due to substances that are released by ______
“local” regulation, tissue cells
_____of flow refers to changes in flow due to vasoconstriction
Neural regulation
_____of flow refers to changes in vessel diameter due to circulation hormones.
Humoral control
