CARDIOVASCULAR

Question 1

Purpose of circulatory system

Answer 1

allows linkage between exchange surfaces and cells throughout body
- exchange of materials

Question 1

what are the three basic components of a complex circulatory system

Answer 1

1. circulatory fluid
2. set of tubes
3. muscular pump

Question 2

explain a single circulation system (closed)

Answer 2

• bony fish and rays
• two chambered heart (atrium and ventricle
• low blood pressure
• no definitive wall between oxygenated and deoxygenated blood
• deoxygenated blood flows from ventricle into an artery. circulates capillaries (gills) to be oxygenated, passes through body into cells via systemic capillaries (O2 exchange). Deoxygenated passes through viens into the atrium ready to start again.

Question 3

explain a double circulation

Answer 3

• amphibians, reptiles and mammals
• 4 chambers
• high blood pressure
• oxygenated and deoxygenated pumped separately (right vs left sides of heart)
• right ventricle pumps deoxygenated blood to the lungs, becomes oxygenated, this blood enters left atrium, then flows into left ventricle, then aorta. Aorta flows to systemic circuit, O2 to tissues. Deoxygenated blood flows back to heart via superior vena cava and inferior vena cava into the right atrium

Question 4

explain the mammalian heart cardiac cycle

Answer 4

• heart contractions called systole where blood is pumped out
• relation and filling with blood = diastole
• occur simultaneously in different parts of heart to keep continuous blood flow

Question 5

what is stroke volume

Answer 5

amount of blood pumped in singular contractions

Question 6

what is cardiac output

Answer 6

volume of blood pumped into the systemic circulation per minute

Question 7

what are atrioventricular valves

Answer 7

• separate each atrium and ventricle
• prevent back flow

Question 8

what are semilunar valves

Answer 8

• control blood flow to aorta and pulmonary artery
• prevent back-flow

Question 9

3 main blood vessels in mammalian system

Answer 9

1. arteries (away)
2. veins (to)
3. capillaries (disperse)

Question 10

what are arterioles, capillaries and capillary beds

Answer 10

arteries branch into arterioles to carry blood to capillaries. networks of capillaries are called capillary beds when chemical exchange occurs

Question 11

what are venules

Answer 11

converge into veins to carry blood to heart

Question 12

what is endothelium

Answer 12

the epithelial layer that lines blood vessels

Question 13

what 3 tissues do both arteries and viens have

Answer 13

endothelium, smooth muscle, connective tissue

Question 14

compare the structure of artery to a vein and capillary

Answer 14

artery - smaller diameter, thicker smooth muscle and connective tissue walls for higher blood pressure (because its being pumped), no valves

vein - wider, thinner tissues, lower pressure of blood flow, valves within endothelium

capillary - smallest diameter, only endothelium (thin) and basal lamina layer (thin) for exchange

Question 15

what causes materials to flow out of capillaries

Answer 15

the difference in blood pressure and osmotic pressure in interstitial fluids (want to equalise)

Question 16

how is foetal circulation different to neonatal?

Answer 16

• nutrients and O2 provided by umbilical cord or placenta
• umbilical vein passes blood into liver (O2 exchange), or bypasses liver via ductus venous shunt directly into vena cava
• blood moves into heart via inferior vena cava after this and then exits the heart via the foramen ovale (middle of heart), then flowing through ductus arteriosus to bypass the lungs and blood flows back to mother for re-oxygenation