block b lecture 2 Flashcards
the heart contraction, receptors, and drugs
5 main functions of cardiovascular system
-rapid transport of nutrients
-removal of waste products of metabolism
-hormonal control by transporting hormones
-temp regulation
-host defense
the walls of the heart are composed of cardiac muscle cells, what is this
myocardium
what is the inner surface of walls that is in contact with the blood
endocardium
what is the inner lining of the pericardium is continuous with the covering of the heart itself
epicardium
what is the fluid filled membranous sac in which the heart is located
pericardium
what are the 2 phases of the cardiac cycle
systole
diastole
what is the name of the contractile phase
systole
what is the name of the relaxation, filling phase
diastole
what are cardiac muscle cells joined together by
gap junctions
what do gap junctions allow for the spread of
excitation from one cell to another
myocardium contains specialized cells that constitute what system
conducting system
what supplies the myocardium with blood
coronary arteries
summary of events leading to cardiac contraction
-depolarization
-opening of voltage ca2 channels
-flow of ca2
-ca2 release
-rise in ca2 conc
-contraction
5 structures that are important to spread electrical activity
-sino-atrial node =pacemaker
-atrial myocardium
-atrioventricular node (tactical pause)
-ventricular conducting fibres (freeways)
-ventricular myocardium (surface roads)
what is an action potential (cardiac)
transient depolarisation of cell membrane
where does cardiac action potential occur
in nodal cells
how is cardiac action potential transmitted
from adjacent myocytes through gap junctions
2 cell types of the intrinsic conduction system
fast depolarising
slow depolarising
what does ARP stand for
absolute refractory period
what does RRP stand for
relative refractory period
ARP in myocytes
250ms
at rest what predominates (para or sympathetic)
parasympathetic
what are sympathetic fibres receptors
noradrenaline -b1 receptors
what do noradrenaline b1 receptors increase permeability of
nodal cell plasma membrane to Na and Ca2
what are parasympathetic fibre receptors
acetylcholine M2 receptors
what do acetylcholine -M2 receptors increase permeability to
K and decrease Na and Ca2
how do you calculate cardiac output
SV x HR
what is stroke volume (SV)
volume of blood pumped per contraction
what is end diastolic volume (EDV)
volume of blood in ventricle before contraction
what is the Frank Starling law of the heart
represents the relationship between stroke volume and end diastolic volume
names of some of the other receptors in the heart
b1 receptor, mostly muscarinic M2
b2
a1 receptors
angiotensin II
what is arterial blood pressure given by
cardiac output (CO) x total peripheral resistance (TPR)
what does total peripheral vascular resistance depend on (TPR)
blood viscosity
arteriolar radius
healthy young adult arterial bp and TPR
120/80 mmHg
what does noreadrenaline a1 (sympathetic nerves) do to arteriolar radius
constrict
what does nerves, acetylcholine, and M3 (sympathetic cholinergic) do to arteriolar radius
dilate
what does b2 (plasma adrenaline) do to arteriolar radius
dilate
what does decreased PO2 and increased PCO2, K, and adenosine do to arteriolar radius
dilate
intermediate reflexes of regulation of arterial blood pressure
baroreceptor reflex
chemoreceptor reflexes
