Chapter 8 - Transport in Animals Flashcards
What is the name given to a change in the oxygen dissociation curve due to increasing CO2 concentration?
Bohr shift
Describe the structure of heamoglobin
- Large globular protein
- 4 polypeptide chains
- 4 Fe2+ ions attached to each haemoglobin
Explain why the blood off loads more oxygen to actively respiring tissues rather than to resting tissues
- Higher levels of CO2 produced
- Lower affinity for oxygen
- Results in the dissociation of carbonic acid leading to the release of oxygen
- More oxygen is released for the same partial pressure than in resting tissue
What is the hydrostatic pressure?
The pressure that a fluid exerts when pushing against the sides of a vessel/ container
What is the oncotic pressure?
The pressure created by the osmotic effects of solutes.
Describe the hydrostatic and oncotic pressure at the arterial end of the capillary
- hydrostatic pressure is higher than the oncotic pressure
- So fluid will move out the capillary forming tissue fluid
Describe the hydrostatic and oncotic pressure at the venous end of the capillary
- hydrostatic pressure is lower than the oncotic pressure.
- So fluid will in to the capillary.
What happens when the overall more fluid leaves the capillary?
The excess tissue fluid is drained in the lymphatic system
State one difference between fetal haemoglobin and adult haemoglobin + reason why difference is essential
- Higher affinity for oxygen
- Partial pressure in placenta is lower
- Because the foetal haemoglobin must be able to bind to oxygen in a lower partial pressure
Why do organisms need specialised transport systems?
- Metabolic demand are high * lots of oxygen and waste produced to remove CO2 and prevent build up of CO2
- SA:VOL small (diffusion not enough)
- Molecules such as hormones or enzymes made in one place but needed in another
- Food digested in one organ system but needs to be transported to every cell for respiration
- Waste products need to be removed from cells to excretory organs
Suggest the main features of multicellular transport systems
- Liquid transport medium that circulates around the system
- Have vessels that carry the transport medium
- Have a pumping mechanism to move fluid around system
What does the circulatory system transport?
Oxygen, CO2, nutrients (e.g. nitrates), waste products (e.g. urea) and hormones
Define mass transport system
substances are transported in a mass of fluid with a mechanism to move fluid around body
What is an open circulatory system?
Circulatory system w a heart but few vessels to contain transport medium
When transport medium is pumped straight into body cavity
What is the open body cavity called? and is it under high or low pressure
Haemocoel
Under low pressure
Comes into contact with tissues and cells
Where exchange takes place between transport medium an cells
Transport medium returns to heart through an open-ended vessel
Split into two by membrane, heart extends along the thorax
Where does gas exchange take place in insects?
In the tracheal system
Where are open-ended circulatory systems mainly found?
-Invertebrate, animals, insects
Describe the features of haemolymph
Blood
-Doesn’t carry oxygen or CO2
-transports food and nitrogenous waste products and cells involved in cell defence
What can’t the haemolymph do?
- Steep conc gradients can’t be maintained for eff. diff
- The haemolymph can’t be varied to meet changing demand
Closed circulatory system
Blood enclosed in blood vessels and doesn’t come directly into contact w cells
Blood pumped under pressure and quickly
Substances leave and enter the blood by diffusion and leave through walls of blood vessels
Vessels can be constricted or dilated to change amount of blood transported
Suggest an advantage to an open circulatory system
Exchange is direct
No diffusion barrier
What is a single circulatory system
- Blood flows through heart once
- Passes 2 sets of cap
What happens in the two capillaries the blood passes?
1st set - O2 and CO2 are exchanged
2nd set- in diff organ system, substances are exchanged between
Is the blood pressure high or low? effect?
Low
-Very narrow 2 sets of vessels * a lot of resistance
-Limits the efficiency of the exchange * activity levels of organism w scc are low
Why are fish an exception?
- They have efficient cs * can be active
- Counter current mechanism in gills which allows more oxygen to be taken from water
- Body weight supported by water, don’t maintain own body temp * reduces demand of bodies
What makes up the double circulatory system?
- Blood is pumped from heart to lungs to pick up oxygen and unload CO2 and returns to heart
- Blood flows through heart and is pumped out to body
- Passes 1 capillary network, so high pressure and fast flow of blood maintained