cardiovascular system

Question 1

what is in blood

Answer 1

red blood cells
white blood cell
platelets
plasma

Question 2

movement of heart

Answer 2

excitation of atria on autonomic pace making activity (sinoatrial node)
depolarises
emits action potential
activation of atria
contraction of ventricles
rest and recovery

Question 3

PQRST complex

Answer 3

P= activation of the atria
QRS= activation of the ventricles
T = recovery wave

Question 4

sympathetic modulation of the heartrate

Answer 4

cardiac nerve releases noradrenaline
acts on B1 adrenergic receptors which are couples to G proteins and stimulate adenylate cyclase
increase production of cyclic AMP
binds to calcium channels altering their voltage sensitivity so threshold is reached more rapidly
increased in no. of action potentials
increased chronotropy and ionotropy
reduces heart rate and reduced cardiac output

Question 5

parasympathetic modulation of the heartrate

Answer 5

vagus nerve releases acetylcholine
acts on M2 muscarinic receptors which are coupled to G proteins
inhibit adenylate cyclase
open G protein linked K+ channels allowing K+ efflux
fewer action potentials
decreased chronotropy

Question 6

risk factors for primary hypertension

Answer 6

age
gender
family
ethnicity - more common in afro-caribbean
obesity
diabetes
diet
smoking promotes vasoconstriction and platelet aggregation
stress increased cortisol promotes vasoconstriction

Question 7

mean arterial blood pressure (MAP)

Answer 7

MAP= CO x PR

CO= cardiac output
PR= resistance against blood flow (peripheral)

Question 8

how to reduce cardiac output

Answer 8

reducing heart rate and force of contraction using B blockers
eg atenolol

Question 9

how to reduce peripheral resistance

Answer 9

promoting vasodilation using a1-adrenergic receptor antagonist