Transport in animals Flashcards
What features do all transport systems in animals have
- a suitable medium in which to carry molecules
- a pump, such as the heart for moving blood
- valve to maintain the flow in one direction
What do some transport system in animal have
- a respiratory pigment in vertebrates and some inverttebrates but not insects which increases the volume of oxygen that can be transported
- a ystem of vessels with a branching network to distribute the transport medium to all parts of the body
What are open circulatory systems
- the blood does not move around the body in blood vessels but it bathes the tissues directly while held in a cavity called the haemocoel
- oxygen diffuses directly onto the tissues from the tracheoles so the blood does not tranport oxygen and has norespiratory pigment
What is the transport system in insects like
- open circulatory system
- no respiratory pigment
- dorsal tubed shape like heart
- inssects have an open blod system. they have a long dorsal (top) tube shaped heat running the length of the body. It pumps blood out at low pressure into the haemocoel where materials are exchanged between the blood and body cells.
- Blood returns slowly to the heart and the open circulation starts again
What is a closed circulatory system
- the blood moves in blood vesselss
- there are two types single and double circulation
Describe the transport system in fish
- single closed circulatory system
- have a respiratory pigmment
- 1 atrium and 1 ventricle - heart
- the ventricle of the hearrt pumps deoxygenated blood to the gill where the well developed capillary network reduces its pressure. Oxygenated blood is carried to the tissues and from there, deoxygenated blood returns to the atrium of the heart
- blood moves to the ventrical and the circulation starts again
What is single circulation
- the blood moves though the heart once in it passage around the body
What is the transport system like in earthworms
- single closed circulatory system
- have a respiratory pigment
- (pseudohearts) - heart
- blood moves forward in the dorsal vessel and back in the ventral vesel
- five pairs of ‘pseuodohearts’ thickened, muscular blood vessels pump the blood from the dorsal to the ventral vessel and keep it moving
What is a double circulatory system
the blood passes through the heart twice in the circuit around the body
Describe the transport system in mammals
- Double closed circulatory system
- have a respiratory pigment
- 2 atria and 2 ventricles - heart
- blood is pumped by a muscular heart at a high pressure giving a rapid flow rate through blood vesse;s
- 0rgans are not in direct contact with the blood but are bathed by tissue fluid, which seeps out of the capillaries
- the blood pigment haemoglobin carries oxygen
What is an advantage of double closed circulatory systems
- Blood pressures is reduced in the capillaries of the lungs and its pressure would be too low to make circulation efficient in the rest of the body
- instead the blood is returned to the hearrt which raises its pressure again to pump it to the rest of the body
- materials are then delivered quickly to the body cells
- oxygenated blood is pumped around the body at a higher pressure
Describe the flow of blood in fish
organs -> veins - > heart -> afferen arteries -> gill capillaries -> efferent arteries -> organs
Describe the flow of blood in mammals
organs -> vena cava -> heart -> pulmanoary artery -> lungs -> pulmonary vein -> heart -> aorta -> organs
Describe the double circulatory system in mammals
- pulmanory circulation
- systematic circulation
- in each circuit the blood passes through the heart twice through the right side and once through the left side
What is pulmonary circulation
- serves the lung
- the right side of the heart pumps deoxygenated blood to the lunds
- oxygenated blood returns from the lungs to the left side of the heart
What is systematic circulation
- serves the body tissues
- the left side of the heart pumps oxygenated blood to the tissues
- deoxygenated blood from the body returns to the right side of the heart
What are the three types of blood vessel
- arteries
- veins
- capillaries
What are the three layers of arteries and veins
- tunica intima
- tunica media
- tunica externa
What is the tunic intima
- the innermost layer
- which is a single layer of endotherlium in some arteries it is supported but elastic rich collagen
- it is a smooth lining reducing friction producing minimal resistance to blood flow
What is the tunica media
- the middle layers
- contains elastic fibres and smooth muscle
- it is thicker in arteries than in veins
- the contraction of the smooth muscle regulated blood flow and maintain the blood pressure as the blood is transported further form the heart
What is the function of the tunica media in arteries
- in arteries the elasic fibres allow stretching to accomodate changed in blood flow and pressure as blood is pumped from heart
- at a certain point stretched elastic fibres recoil pushing blood on throguh the a\rtery
- this is felt as the pulse and maintain the blood pressure
Wha is the tunica externa
- the outer layer
- contains collagen fibres which resist overstretching
What is the function of arteries
- carry blood away from the heart
- their thick muscular walls withstand the blood’s high pressure, derived from the heart
- arteries branch into smaller vessels called arterioled that further subdivide into capillaries
What is the function of capillaries
- form a vast network that penetrated all the tissues and organs of the body
- blood from the capillaries collects into venules which take blood into veins which return it to the heart
What are the functions of veins
- have a larger diameter lumen and thinner walls with less muscle than arteries
- consequentlu the blood pressure and the flow rate are lower
- for veins above the heart blood return to the heart by gravity
- it moves through other veins by the pressure from the surrounding muscles
- veins have semi lunar valve along their length ensuring flow in onve direction and preventing backflow these are not present in arteries other than at the base of the aorta and pulmonary artery
- the fault functioning of the valves can contribute to the varicose veins and heart failure
What is the structure of capillaries
- thin walls which are only one layer of endothelium on a basement membrane
- pores between the cells make the capillary walls permeable to water and solutes such as glucose so exchange materials between the blood and the tissues take place
How are capillaries adapted to their function
- capillarie have a small diameter and the rate of blood flow slows down
- there are many capillaries in a capillary bed which reduces the rate of blood flow so that there is plenty of time for the exchange of materials with the surrounding tissue fluid
What is the heart and why is it thought as two seperate pumps
- a pump to circulate blood is essential for a circulatory system
- the heart can be thought of as two seperate pumps one dealing with oxygenated blood and the oher with deoxygenated blood
- these are two relativley thin walled collection chambers the atria whcih are above two thickeer walled pumping chambers
- the ventricalses allowing the complete seperation of oxygenated and deoxygenated blood
What does the heart consist of
- cardiac muscle a specialised tissue with myogenic contraction
why is cardiac muscle specialied for the heart
- cardiac muscle never tires
what is myogenic contraction
- the heartbeat is initiated within muscle cells themselves and is not dependent on nervous or hormonal stimulation
systole
A stage in the cardiac cycle in which heart muscle contracts
Diastole
A stage in the cardiac cycle in which heart muscle relaxes
What is the cardiac cycle
- describes the sequences of events of one heartbeat
- the action of the heart consists of alternation contractions (systole) and relaxations (diastole)
What are the three stages of the cardiac cycle
- atrial systole
- ventricular systole
- diastole
What is atrial systole
- The atrium walls contract and the blood pressure in the atria increases
- This pushes the blood through the tricuspid and bicuspid valves down into the ventricles which are relaxed
What is ventricular systole
- the ventricle walls contract and increase the blood pressure in the ventricles
- this forces blood up through the semi lunar valves out of the heart into the pulmonary artery and the aorta
- the blood cannot flow back from the ventricles into the atria because the tricuspid and bicuspid calces are closed by the rise in ventricular pressure
- the pulmonary artery carries deoxygennated blood to the lungs and the aorta carries oxygenated blood to the rest of the body