transport in animals

Transport in animals

(a) the need for transport systems in multicellular animals To include an appreciation of size, metabolic rate and surface area to volume ratio

ALL ANIMALS HAVE CIRCULATORY SYSTEMS TO TRANSPORT SUBSTANCES AROUND THEIR BODIES.

ALL ORGANISMS GET BIGGER, (SURFACE AREA TO VOLUME RATIO DECREASES)THE DISTANCE BETWEEN THE CELLS GET GREATER AS DIFFUSION IS ONLY EFFECTIVE OVER VERY SHORT DISTANCE. RELYING ON DIFFUSION WOULD BE FATAL AND THE ORGANISM WOULDN'T SURVIVE THEREFOR ORGANISMS NEED A SPECIALISED TRANSPORT SYSTEM.

THE NEED FOR SPECIALISED TRANSPORT SYSTEM AND WEATHER IT IS CIRCULATED BY A PUMP DEPENDS ON:

• THE SURFACE AREA TO VOLUME RATIO AS MULTICELLULAR ORGANISMS GET BIGGER THE DIFFUSION PATHWAY GETS BIGGER BUT THE SURFACE AREA GETS SMALLER 

• ACTIVITY OF THE ORGANISM- ACTIVE ORGANISMS NEED LOTS OF OXYGEN, FOOD AND PRODUCE LOTS OF WASTE 

(b) the different types of circulatory systems To include single, double, open and closed circulatory systems in insects, fish and mammals. 

OPEN CIRCULATORY SYSTEMS:

IN OPEN CIRCULATORY  SYSTEMS THE ORGANISMS BLOOD IS FREE TO FLOW FROM THE HEART INTO  THE BODY CAVITY AND COMES IN DIRECT CONTACT WITH THE CELLS  OPEN CIRCULATORY  SYSTEMS ARE FOUND IN INSECTS.

CLOSED CIRCULATORY SYSTEM: 

IN CLOSED CIRCULATORY SYSTEMS, THE BLOOD IS RESTRICTED TO FLOWING THROUGH THE BLOOD VESSELS AND A PUMP (THE HEART) IS REQUIRED TO GET BLOOD TO ALL PARTS OF THE BODY.

CLOSED CIRCULATORY SYSTEMS ARE FOUND IN MAMMALS AND FISH. IN CLOSED SYSTEM THE BLOOD IS ENCLOSED IN BLOOD VESSELS AND DOESN'T COM IN DIRECT CONTACT WITH THE CELLS BLOOD IS PUMPED UNDER PRESSURE AND THING LEAVE THROUGH THE WALL OF THE BLOOD VESSEL. THE AMOUNT OF BLOOD FLOWING CAN BE ADJUSTED BY WIDENING OR NARROWING THE BLOOD VESSEL.

  THERE ARE DIFFERENT TYPES OF CIRCULATORY SYSTEMS :

• SINGLE CLOSED CIRCULATORY SYSTEMS (FISH HAVE)

IN SINGLE CIRCULATORY SYSTEMS BLOOD ONLY TRAVELS THROUGH THE HEART ONCE IN EVERY CIRCUIT AROUND THE BODY. THE HEART HAS 2 CHAMBERS . IT PASSES THROUGH 2 SETS OF CAPILLARIES, ONE TO EXCHANGE OXYGEN,CARBON DIOXIDE AND THE OTHER BETWEEN THE BLOOD AND THE CELL.

BECAUSE IT GOES THROUGH 2 SETS OF NARROW VESSELS ,THE PRESSURE IS LOW THIS LIMITS EXCHANGE PROCESS

• DOUBLE CLOSED CIRCULATORY SYSTEM (MAMMALS HAVE )

IN DOUBLE CIRCULATORY SYSTEMS THE BLOOD TRAVELS THROUGH THE HEART TWICE PER CIRCUIT. DOUBLE CIRCULATORY SYSTEMS GET OXYGENATED BLOOD TO THE TISSUE (LIKE MUSCLE) THAT NEEDS IT FASTER THAN A SINGLE CIRCULATORY SYSTEMS ALSO THE CONCENTRATION GRADIENT BETWEEN BLOOD AND CELLS  IS BETTER MAINTAINED IN A DOUBLE CIRCULATORY SYSTEM SO THAT SUBSTANCES ARE EXCHANGED BETWEEN THE BLOOD AND THE BODY MUCH FASTER.

DEOXYGENATED BLOOD IS PUMPED TO THE LUNGS 

OXYGENATED BLOOD IS PUMPED AROUND THE BODY  

(c) THE STRUCTURE AND FUNCTION OF ARTERIES, ARTERIOLES, CAPPILERIES, VENULES, VEINS TO INCLEDE THE DISTRIBUTION OF DIFFERENT TISSUE WITHIN THE VESSEL WALLS

ARTERIES (CARRY BLOOD AWAY FROM THE HEART ):

• TOUGH OUTER WALL IS MADE OF AN OUTER LAYER OF CONNECTIVE TISSUE WITH FIBRES OF COLLAGEN TO PREVENT OVERSTRETCHING AND TO PROTECT AGAINST PRESSURE…