CV System

Question 1

CV system components

Answer 1

Heart, blood and blood vessels.

Question 2

Right atrium

Answer 2

Receives blood from Inferior/Superior vena cava and coronary sinus. Holds -O2 blood. Has pectinate muscles which may aid contraction.

Question 3

Left atrium

Answer 3

Receives blood from the PC via 2L/2R pulmonary veins. Has pectinate muscles as well.

Question 4

Right ventricle

Answer 4

Has trabecular carnae. Papillary muscles anchor the chordae tendinae of the heart valve. -O2 blood.

Question 5

Left ventricle

Answer 5

Thickest heart chamber bc myocardium needs to generate higher BP to force blood through SC. Has trabeculae carnae and papillary muscles.

Question 6

Atrioventricular valves

Answer 6

Right AV = tri, left AV =bi. Locked between atria and ventricles.

Question 7

Semilunar valves

Answer 7

At base of aorta and base of pulmonary trunk. Open when higher ventricular BP forces them apart.

Question 8

Blood flow overview

Answer 8

RA - tri valve - RV - pul. valve - Pul trunk + arteries - Lungs - pul. veins - LA - bi valve - LV - aortic valve - aorta and systemic arteries - systemic capillaries

Question 9

Depolarisation rates in SA Node, AV Node and AV bundle, bundle branches and Purkinje fibres

Answer 9

SA - 100/min
AV - 40-60/min
AV b,bb,Pf - 20-35/min

Question 10

Autorhytmic Cell AP

Answer 10

No stable rm potential. Slow depolarisation as calcium has slow influx. Repolarisation due to efflux of potassium and Ca++ channels closing.

Question 11

Cardiac contractile fibres

Answer 11

Stable rm potential of -90mV. Fast VG nA+ channels, plateau caused by opening of slow Ca++ channels. Repolarisation due to rapid efflux of K+.

Question 12

Ca++ binding to troponin causes

Answer 12

Tropomyosin moves and allows the binding of actin and myosin.