Heart Stuffs

Question 1

Closed circulation

Answer 1

Blood in blood vessels

Quickly delivered to tissues

Question 2

Insects

Answer 2

Haemolymph moves in haemocoel by a heart

No haemoglobin to transport oxygen

Gain oxygen from tracheoles

Question 3

Single circulation

Answer 3

Blood pass through heart once in each circulation- heart has 2 chambers

Atrium receives deoxygenated blood

Ventricle pumps blood to gills via afferent arteries- gains O2 and flows through efferent arteries to organs.

Loses pressure around circuit so slower

Question 4

Double circulation

Answer 4

High pressure and fast

Pulmonary takes deoxygenated blood from heart to lungs and O2 blood from lungs to heart

Systemic takes O2 blood from heart to body tissues and no O2 blood back to heart

Question 5

Open circulation

Answer 5

Blood ‘bathes’ cells and organs of the body- called haemolymph and is in body cavity or haemocoel

Question 6

Myogenic

Answer 6

Stimulated to beat from within muscle wall- if isolated from nerve supply will continue to beat but irregularly

Question 7

Group of cells in right atrium (SA node)

Answer 7

Pacemaker

Sends out wave of excitation across muscle of atria

Muscle contracts- wave of excitation is wave of depolarisation of muscle cells- when they relax they are repolarized

Question 8

Fibrous tissue between atria and ventricles

Answer 8

Prevents wave of excitation passing to the ventricles

Question 9

AV node (in septum at atrioventricular junction)

Answer 9

Delays wave of excitation allowing atria to complete contraction and ventricles to fill

Ensuring ventricles contract after atria