CVS1 Flashcards
the SA node is the pacemaker. TRUE OR FLASE?
TRUE
There is a delay in the action potential at the AV node. TRUE OR FALSE?
TRUE
Where is the cardiovascular centre located?
In the medulla oblangata
In the medulla oblaganta there Baroreceptors, parasympathetic and sympathetic receptors. TRUE OR FLASE?
TRUE
If the cardiovascular centre detetcts low BP what system is turned on?
Sympathetic nervous system
If the cardiovascular centre detetcts high BP what system is turned on?
Parasympthetic nervous system
What occurs in the SA node when BP is low?
- CV centre activates the sympathetic nerous system
- Noradrenaline binds to B1
- Increase in pacemaker current
- This leads to an increase in slope phase 4 of action potential
What occurs in the AV node when sympathetic system is activated due to low BP?
- Noradrenaline binds
- Increase in ca2+ current
- Increase in slope phase 0 of action potential
- Also increases velocity conductivity
- Increase in contractitlity of myocytes
What occurs in the SA node in parasynthetic nervous system when BP is high?
- Ach binds to muscarinic receptors which slows depolisation
- Opens K+ channels
- Inhibits Na+ channel from opening which slows down slope of phase 4 of the action potential
What occurs in the AV node in the parasympathetic nervous system when BP is high?
- Ach binds to muscarinic receptors
- This slows down conduction velocity which slows slope phase 0 of action potential
Baroreceptors send afferent fibres to the cardiac ocntrol centre (medulla). TRUE OR FALSE?
TRUE
What are the two types of baroreceptors?
- carotid
- aortic
What occurs when BP is high with Baroreceptors?
- Baroreceptors stimulate parasympathetic outflow which causes SA node to stop firing
- Parasympathetic outflow inhibits sympathtic nervou system from inducing vasoconstriction
The parasymthpathetic NS has no direct effect with vasodilation. TRUE OR FLASE?
TRUE
What occurs when BP is low with Baroreceptors?
- Baroreceptors stimulate sympathetic outflow which causes an increase in SA node firing
- Sympathetic nervous system increases vasoconstriction which increases venous return and hence increases cardiac output
what is heart failure?
- When the output of the heart is insufficient to meet the needs of the body
What can heart failure come from?
- Insufficient cardiac output from reduced left ventricular contractility
- Inadequate venous return which can come from inadequate diastolic relaxation
What are some symptoms of HF?
- Tachycardia (compasates)
- Shortness of breath, tiredness
- Oedema
What are the possible underlting causes of HF?
- Coronary artery diseas
- Arrythmias
- Hypertention
- Myocardial disease