Class 12 Flashcards
Cardiovascular function can be controlled through the regulation of what two things?
Blood pressure and blood volume
What are the two basic categories of cardiovascular function control?
Neural control and Humoral control
Neural control is what kind of control?
Autonomic
Humoral control is what kind of control?
Hormonal
What are the three levels of neural control?
1) higher centres like cortex
2) Hypothalamus
3) Medulla of the brain stem
What is the cortex connected to?
Hypothalamus and medulla
What are the higher levels like the cortex rolls in neural control of cardio function?
Responsible for modulating cardiovascular responses during emotional stress
What is the hypothalamus role in neural control of cardio function?
Plays an integrative role by modulating medullary neural activity
The hypothalamus can influence what? Which involves the increase of HR and BP in response to stress
The autonomic system
Baroreceptors, chemoreceptors And stretch receptors are found where in the brain?
Medulla of the brain stem at the nucleus tractus solitarius
Does the medulla have sympathetic or parasympathetic centers?
Both
The nucleus tractus solitarius can produce what kind of affect?
A calming effect
Which effects are dominant innervation on cardio function? (parasympathetic or sympathetic)
Parasympathetic
Parasympathetic nuclei have what kind of activity? Even under resting conditions
They are tonically active
Resting heart rate is lower than what other rate?
Intrinsic firing rate of the SA node
Parasympathetic activity creates a negative or positive chronotropic affect?
Negative
Sympathetic activity creates a positive or negative chronotropic and inotropic effect?
Negative
The right vagus generally innervates what?
The SA node
The left vagus primarily intervates what?
AV node and the ventricular conduction system
How does parasympathetic stimulation induce vasodilation?
By inhibiting sympathetic centre through interneuron in the level of NTS
Stimulation of sympathetic innervation on cardiovascular function is the effects of what?
Norepinephrine
Stimulation of the sympathetic innervation on cardio function produces what?
Tachycardia and systemic vasoconstriction
Removal of sympathetic influence will produce what? In regards to the cardio function
Vasodilation and hypotension
Sympathetic activation constricts both the what on arteries and the what on veins
Resistance on arteries and capacitance veins
Sympathetic stimulation on a heart produces what kind of vasoconstriction?
Transient coronary vasal constriction
What is the primary variable that needs to be regulated for the control of cardio function?
Systemic arterial blood pressure
What two factors do you need to have in order to have a good tissue perfusion?
Good BP and good blood volume
Within the cardio system, sensory mechanisms monitor the variability of BP and volume through what?
Negative feedback loops
What are the four major hormonal factors in the cardio system?
1) Catecholamines
2) Renin-angiotensin-aldosterone system
3) Atrial natriuretic peptide
4) Vasopressin or anti diuretic hormone
Catecholamines are mostly from where?
Adrenal medulla
What are the two catecholamines?
Epinephrine and norepinephrine
Does vasodilation increase or decrease blood pressure?
Decrease
Decrease blood pressure increases or decreases heart rate?
Increases
How are catecholamines activated?
By preganglionic sympathetic nerves during stress
Epinephrin and norepinephrine have a high affinity for what? And a low affinity for what?
High affinity for B2, low affinity for B1
How do Catecholamines cause vasodilation?
Binds to adrenoeceptors on small arteries, when epinephrine levels are low
At low to moderate levels of epinephrine, what happens to HR, contractibility, and conduction velocity?
All increased
What metabolic dilator tends to counteract the vasoconstrictor effect of Epi?
Adenosine
What is the three basic mechanisms epi increases blood pressure?
1) Direct stimulation of myocytes in ventricles
2) increases HR mediated by B one receptor
3) Vasoconstriction in resistance vessels and veins
The renin angiotensin aldosterone system increases what and what?
BP and blood volume
Atrial natriuretic peptide decreases what and what?
BP and blood volume
Vasopressin increases what?
BP and blood volume