topic 1 - cv system

Question 1

what is an open circulatory system?

Answer 1

• blood circulates in large open spaces
• simple heart
• blood pumped into cavities around organs
• diffusion takes place

Question 2

what is a closed system ?

Answer 2

• all vertebrates
• blood enclosed in vessels
• higher blood pressures
• faster = more efficient
• capilleries come into contact with cells and diffuse
  larger sa:v ratio

Question 3

what is a single circulatory system

Answer 3

• blood , vessels and a heart
• all pumped in same direction
• one single loop
  e.g fish, blood -> gills -> gaseous exchange -> blood flows around body back to heart

Question 4

what is a double circulatory system?

Answer 4

• birds + mammals
• left and right side of heart
• blood flows through heart twice in each circulation
• heart gives blood from lungs extra boost
• animals with a higher metabolic rate + S:V ratio.

Question 5

what is the heart made of ?

Answer 5

cardiac muscle

Question 6

what structures in the heart pump deoxygenated blood

Answer 6

• pulmornary artery
• vena cava

Question 7

what structures of the heart pump oxygenated blood

Answer 7

• pulmornary vein
• aorta

Question 8

name the valves in the heart + location

Answer 8

• left atrioventricular, between left atria and left ventricle
• aortic valve (semilunar) between left ventricle and aorta
• right atrioventricular
• semi lunar between pulmornary artery and ventricle

Question 9

features of an artery

Answer 9

• narrow lumen
• thick walls
• more collagen, smooth muscle , elastic fibres
• no valves
• high pressure

Question 10

features of a vein

Answer 10

• wide lumen
• thinner walls
• less collagen , smooth muscle, elastic fibres
• low pressure

Question 11

what are the stages of the cardiac cycle ?

Answer 11

• diastole
• atrial systole
• ventricular systole

Question 12

what happens during diastole ?

Answer 12

• atria and ventricles relax
• pressure lowers in chambers
• blood drawn back to ventricles from pulmonary artery and aorta
• semi lunar valves close preventing further backflow
• low pressure in atria helps draw blood in from veins.
• AV valves closed

Question 13

describe atrial systole

Answer 13

• Atria fill
• increased pressure forces AV valves to open and blood leak into ventricles
• atria contacts forcing more blood into ventricles

Question 14

describe ventricular systole

Answer 14

• slight delay
• contract from base up
• pressure increases
• SL valves open
• blood pushed up and out through aorta and pulmonary artery
• pressure forces AV valves closed preventing backflow