Transport in Animals

Question 1

Benefits of double circulatory system?

Answer 1

• Maintains higher blood pressure and avg speed of flow (passes through 1 capillary network before returning to heart as opposed to 2)
• Steeper concentration gradient
• Allows efficient exchange of nutrients and waste with surrounding tissues

Question 2

Closed Circulatory system

Answer 2

Blood is pumped around body in blood vessels

Question 3

Open circulatory system

Answer 3

Blood is pumped directly into body cavities (not with vessels)

Question 4

Pathway of blood in insects

Answer 4

• Tubular heart pumps haemolymph into dorsal vessel
• Haemolymph is pumpe to the haemocoel (body cavity)
• Surrounds organs then enters heart via Ostia (one way valve)

Question 5

Arterioles

Answer 5

• Narrower blood vessels
• Branched from arteries
• Transport blood into capillaries

Question 6

Arteries

Answer 6

Transport blood from the heart to the body

Question 7

Veins

Answer 7

Transport blood from the body to the heart

Question 8

Venules

Answer 8

Transport blood from capillaries to veins

Question 9

Cooperative binding

Answer 9

• When quaternary structure of haemoglobin is altered by oxygen molecules binding to haem group

-So affinity for oxygen increases

Question 10

What is a high affinity for oxygen?

Answer 10

• Oxygen binds easily
• Dissociates slowly

Question 11

What is a low affinity for oxygen?

Answer 11

• Oxygen binds slowly
• Dissociates easily

Question 12

Arteries Structure

Answer 12

3 Layers

• Endothelial layer (connective tissue and elastic fibres)
• Thick layer of elastic tissue with smooth muscle cells)
• Collagen (strong, prevents over-stretching)
• Narrow lumen

Elastic fibres maintain pressure, smooth muscle cells can contract

Question 13

Structure of arterioles

Answer 13

• Muscular layer so can partially cut of blood flow

So parts of the body which dont need blood can be ignored

Question 14

Structure of veins

Answer 14

• Wide lumen, so pressure is low
• Valves

Question 15

Structure of Capillaries

Answer 15

• Small diameter
• Walls one cell thick (endothelial cells)

Question 16

What is hydrostatic pressure

Answer 16

Pressure exerted by fluids

Question 17

What is oncotic pressure

Answer 17

Osmotic pressure exerted by plasma proteins

Question 18

How is carbon dioxide transported?

Answer 18

• Dissolved into blood plasma
• Binds to haemoglobin (carbaminohaemoglobin)
• Hydrogen carbonate IONS

Question 19

Formation of hydrogen carbonate ions (long)

Answer 19

• CO2 diffuses from plasma to RBCs
• CO2 binds to H2O forming H2CO3 (CARBONIC ACID)
• Carbonic anhydrase, present in RBCs catalyses reaction between water and co2
• Carbonic acid dissociates readily into H+ ions and HCO3-
• H+ ions bind with haemoglobin forming haemoglobinic acid (prevents H+ ions from decreasing pH of RBC) (Haemoglobin acts as a buffer)
• HCO3- ions diffuse out of RBC into blood plasmas where they are transported in solution (via a transport protein)

Question 20

What is the Chloride shift?

Answer 20

• Movement of Cl ions into RBCs when hydrogen carbonate ions are formed
• To prevent electrical imbalance, negatively charged chloride ions are transported into RBCs via the same transport protein
• Prevents RBCs from becoming positively charged as a result of buildup of hydrogen ions