Transport in Animals Flashcards
Benefits of double circulatory system?
- 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
Closed Circulatory system
Blood is pumped around body in blood vessels
Open circulatory system
Blood is pumped directly into body cavities (not with vessels)
Pathway of blood in insects
- 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)
Arterioles
- Narrower blood vessels
- Branched from arteries
- Transport blood into capillaries
Arteries
Transport blood from the heart to the body
Veins
Transport blood from the body to the heart
Venules
Transport blood from capillaries to veins
Cooperative binding
- When quaternary structure of haemoglobin is altered by oxygen molecules binding to haem group
-So affinity for oxygen increases
What is a high affinity for oxygen?
- Oxygen binds easily
- Dissociates slowly
What is a low affinity for oxygen?
- Oxygen binds slowly
- Dissociates easily
Arteries Structure
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
Structure of arterioles
- Muscular layer so can partially cut of blood flow
So parts of the body which dont need blood can be ignored
Structure of veins
- Wide lumen, so pressure is low
- Valves
Structure of Capillaries
- Small diameter
- Walls one cell thick (endothelial cells)
What is hydrostatic pressure
Pressure exerted by fluids
What is oncotic pressure
Osmotic pressure exerted by plasma proteins
How is carbon dioxide transported?
- Dissolved into blood plasma
- Binds to haemoglobin (carbaminohaemoglobin)
- Hydrogen carbonate IONS
Formation of hydrogen carbonate ions (long)
- 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)
What is the Chloride shift?
- 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
