Physiology Flashcards
What is feedforward?
a change made in anticipation of a change
What is feedback?
a change after a change has been made
What are the three functions of the lipid bilayer?
structure
hydrophobic interior is a barrier
fluidity of the membrane
What are the two types of proteins in the lipid bilayer?
peripheral aren’t embedded
integral either span, half span or are lined to an embedded protein
What are the functions of integral proteins?
ligand-binding receptors adhesion molecules pores or channels carriers pumps enzymes intracellular signalling
What do docking-markers do?
on inner membrane surface and interact with secretory vesicles leading to exocytosis
What is the glycocalyx?
sugar coating of glycoproteins and glycolipids
What are the roles of carbohydrates in cell membranes?
different markers for embryonic development
tissue growth so tissues don’t overgrow territory
What is pulse pressure?
difference between systolic and diastolic
How is MAP calculated?
((2xdiastolic) + systolic)/3)
What is the minimum MAP needed and why is it needed?
60mmHg and must be high enough to perfuse brain, heart and kidneys but not too high that vessels burst
Where are the baroreceptors?
aortic arch and in the carotid
What happens to the firing rate of the baroreceptors when MAP increases?
increased rate of firing
What happens to the firing rate of the baroreceptors when MAP decreases?
decreased rate of firing
What happens to CNS afferent impulses that reach the cardiovascular control centre?
info sent to brain areas
generates vagal outflow to the heart
regulates spinal sympathetic neurones
What does MAP equal and what does CO equal?
MAP=COxSVR
CO=SVxHR
What does noradrenaline act on to change HR and what does it cause?
beta 1 receptors to cause tachycardia
What does acetylcholine act on to change HR and what does it cause?
muscarinic receptors to cause bradycardia
Does parasympathetic or sympathetic affect ventricular contraction?
only sympathetic
What does vasoconstriction do?
increases SVR and MAP
What does vasodilation do?
decreases SVR and MAP
What does noradrenaline act on to change vasoconstriction/vasodilation?
alpha receptors to produce parasympathetic vasomotor tone at rest
Which one does not innervate the arterial smooth muscle- sympathetic or parasympathetic?
parasympathetic does not innervate the arterial smooth muscle
What does increased sympathetic discharge do to SVR?
increases it
What does decreased sympathetic discharge do to SVR?
decreases it
What is the process of events after there is a decreased ABP?
decreased baroreceptor discharge
CV centre in medulla causes
- decreased vagal so increased HR so increased CO so increased ABP
- increase sympathetic so increased SV and HR so increased CO so increased ABP
- increased sympathetic constrictor tone so increased venoconstriction (increased SV) and increased vasoconstriction (increased SVR)
What is the process of events after there is a increased ABP?
increased baroreceptor discharge
CV centre in medulla causes
- increased vagal so decreased HR so decreased CO so decreased ABP
- decrease sympathetic so decreased SV and HR so decreased CO so decreased ABP
- decreased sympathetic constrictor tone so decreased venoconstriction (decreased SV) and decreased vasoconstriction (decreased SVR)
Why do baroreceptors only provide short-term control of ABP?
they re-set at a higher steady state