8.1 Transport systems in multicellular animals Flashcards
What 5 processes in prokaryotes [Single-Celled Organisms] can supply everything the cell needs to import and export?
Diffusion Osmosis Active transport Endocytosis Exocytosis
What happens to the distance between the cells and the outside of the body as organisms gets bigger?
It increases
Why are specialised transport systems needed in larger organisms? (5 reasons)
- To meet high metabolic demands; diffusion over long distances is not enough to supply required quantities
- To combat surface area:volume (SA:V) decrease / organism size increase
- Hormones/enzyme transportation
- To transport digested food in one organ system to every cell for use of respiration and other aspects of cell membrane
- Removal of metabolic waste products from cells to excretory organs
What do circulatory systems carry around the body?
Oxygen, carbon dioxide, nutrients, waste products and hormones.
What do most circulatory systems have in common? (3 similarities)
- liquid transport medium (blood/haemolymph)
- vessels that carry transport medium
- pumping mechanism to move fluid around the system
In what way is the transport medium held and pumped in an [Open Circulatory System]?
- few vessels to carry transport medium; pumped from heart to body
What is the open body cavity called in the [Open Circulatory System]?
The haemocoel
Describe how transport medium is transported (pressure) in the haemocoel?
Under low pressure
How does [Open Circulatory System] transport medium around?
A few vessels contain the medium and the medium is pumped straight from the heart into the body cavity (haemocoel) of the animal
In the haemocoel the transport medium is under low pressure and they get into direct contact with the
tissues and the cells. Were exchange takes place between the transport median and the cells
The transport median returns to the heart through an open-ended vessels
In what group of species are open-ended circulatory systems found?
Invertebrate animals (inc. insects, molluscs)
In insects, in what system does gas exchange take
place in?
The tracheal system
What is insect blood known as?
Haemolymph
What components are carried and not carried by the haemolymph?
- Does carry;
a) food
b) nitrogenous waste products
c) cells involved in defence against disease - Does not carry;
a) oxygen
b) carbon dioxide
What is the body cavity (haemocoel) split by?
A membrane
Where does the heart extend along in insects?
The length of the thorax and the abdomen
Haemolymph circulates, but what cannot be maintained in terms of diffusion?
A steep diffusion gradient for effective diffusion
In regards to the haemolymph, what cannot be varied to meet changing demands?
The amount of haemolymph
Where is blood enclosed in closed circulatory systems?
Blood vessels
True/False - blood comes into direct contact with cells of the body in a closed circulatory system
False
In a closed circulatory system, is the blood pumped under pressure at a relatively quick pace? (Yes/No)
Yes
In a closed circulatory system, how do substances leave and enter the blood?
By diffusion through the walls of the blood vessels
How can the amount of blood flowing to a particular tissue be adjusted in a closed circulatory system?
By widening or narrowing blood vessels
In most closed circulatory systems, what does the blood contain that carries the respiratory gases?
A blood pigment
What species tend to have a [Closed Circulatory System]?
Many different animal phyla, including;
- echinoderms (sea urchins, starfish)
- cephalopod molluscs (octopods, squid)
- annelid worms (common earthworm)
- all vertebrate groups (mammals)
Where are [Single Closed circulatory Systems] commonly found?
Fish and annelid worms
In single closed circulatory systems, how many sets of capillaries does blood pass through before it returns to the heart?
Two
In single closed circulatory systems, with regards to blood passing through the first capillaries, what gases are exchanged?
Oxygen and carbon dioxide
In single closed circulatory systems, with regards to the second set of capillaries that blood passes through, where are substances exchanged?
Within different organ systems - between the blood and the cells
What effect does blood passing through two sets of very narrow vessels in single closed circulatory systems have on the rate blood is pumped back to the heart?
Blood pressure drops considerably in the system; blood returns to the heart quite slowly
In single closed circulatory systems, how do the activity levels of animals tend to be quite low?
Blood pumps back to the heart slowly, so the efficiency of exchange processes is limited
In single closed circulatory systems, which set of animals tend to deviate from being relatively unactive?
Fish - they have a relatively efficient single closed circulatory system, meaning they can be very active
What features do fish have that allow them to be active and combats them having a single closed circulatory system?
Body weight supported by the water and do not maintain their own body temperature allows them to reduce metabolic demands
Have an efficient gaseous exchange system, allows fish to be so active.
A counter-current gaseous exchange system in their gills, so that they can take up a lot of oxygen from the water
{This allows them to be active with a Single Closed Circulatory System}
What positive attributes do organisms with Double Closed Circulatory systems maintain?
- Relatively high activity
- Self-maintenance of body temperature
Which transport system is the most efficient for transporting substances around the body? And why?
Double closed circulatory system
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—-> This is because it allows animals to maintain there own body temperature
What happens in the Double Closed Circulatory System (how does blood travel)?
Blood is pumped from the heart to the lungs to pick up oxygen and unload carbon dioxide - it then returns to the heart.
Blood flows through the heart and is pumped out to travel all around the body before returning to the heart again.
In a [Double Closed Circulatory system] - how can relatively high blood pressure and fast flow of blood be maintained?
By allowing in each circuit - blood to only pass through one capillary network, which means a relative high pressure
In [Single Closed Circulatory System] - How does blood travel through the body and how are substances exchanged?
In Single Closed Circulatory System - the blood passes through two sets of capillaries (microscopic blood vessels) before it returns to the heart:
(In the 1st set of capillaries) There is an exchange of oxygen and carbon dioxide
(In the 2nd set of capillaries) In different organ systems, substances are exchanged between blood and cells. As a result, passing through the two sets of very narrow vessels, the blood pressure in the system drops considerably so the blood returns to the heart quite slowly
{Blood flows through the heart once}
What are the limitation with animals having a single closed circulatory system?
Due to blood being slow to move back to the heart - this limits there efficiency of the exchange processes so the activity levels of animals with single - celled circulatory
What is the mass transport system?
Is the system when substances are transported in a mass of fluid with a mechanism for moving the fluid around the body
What are the two types of circulation systems that can be found in multi-cellular organisms?
Open Circulatory System
Closed Circulatory System
Why would multi-cellular organisms not be able to survive without specialised transport systems?
This is because diffusion alone would be too slow that the organism would not be able to survive
Why do organisms need “transport systems”?
So that they can supply oxygen and nutrients to the sites, where they are needed and remove waste products from individual cells.
What are the types of circulatory systems?
Open Circulatory System
Closed Circulatory System
Single Closed Circulatory System
Double Closed Circulatory System
