Transport in animals Flashcards
haemocoel
the main body cavity found in most invertebrates that contains a circulatory fluid
What do transport systems have
- medium - to carry dissolved substances
- pump - move materials
- respiratory pigment eg haemoglobin (not insects) - to carry dissolved gases
- system of vessels with valves to ensure on way flow
What is an open circulatory system what organism has this
- blood does not move around the body in blood vessels
- cells are bathed by blood or a fluid called haemolymph in a fluid filled space around the organs called a haemocoel return slowly to the dorsal - tube shaped heart
- no need for a respiratory pigment as oxygen is supplied directly to tissues via the tracheal system
- insects
why are open circulatory systems often ineffecient
don’t control the distribution of respiratory gases
What is a closed circulatory system
- use blood vessels
What is an advantage to closed circulatory systems
- use blood vessels
- blood can be transported more quickly under higher pressure to all parts of the animal’s body
What are the two types of closed circulatory systems
- single
- double
What is a single circulatory system
- involves blood passing through the heart once during its passage around the body
What sort of circulatory system is found in fish
- single closed
- blood pumped to the gills and onto the body organs before returning to the heart
What sort of circulatory systen is found in an earthworm
- single closed
- five pairs of pseudohearts (thickened muscular blood vessels) pump blood from the dorsal vessel to the ventral vessel
What is a double circulatory system
- involves blood passing through the heart twice
What is the circulatory system found in mammals
- double closed
- pulmonary circulation supplies the lungs where blood is oxygenated
- systematic circulation supplies body with oxygenated blood
What are the advantages of a double circulatory system over single
- meets demand of mammals with high metabolic rates
- a higher blood pressure and faster circulation can be sustained in a systematic circulation
- oxygenated and deoxygenated blood are kept seperate which improves oxygen distribution
What is the function of arteries and describe the adaptations as well as change in pressure and rate of blood flow
- carry blood away fro the heart
- thick walls to resist high blood pressure
- elastic fibres stretch to allow the arteries to accommodate blood and the elastic recoil of the ffribres pushes blood along the artery
- the pressure in these arteries rythmically rise and fall corresponding to verntricular systol
- as blood flows along the artery friction with the vessel walls cause blood pressure and rate of blood flow to decrease
How are arterioles formed and what are the adaptations of an arteriole as well as change in pressure and rate of blood flow
- main arteries continually branch to form smaller arteries and eventually arterioles
- arterioles have a large total surface area and relativley narrow lumen causing further reduction in pressure and rate of blood flow
- smooth muscle tissue whcih widen or narrow the lumen to increase or decrease blood flow
What are the function of capillaries annd what are it’s adaptations as well as change in pressure and rate of blood flow
- million of capillarie to form dense networks in tissues
- have narrow lumer but there total cross sectional area is very large
- as blood flows throught the capillaries both blood pressure and rate of blood flow decreae
- due to the increase in total cross sectional area and frictional resistance of blood flowing along the blood vessels
- there function is to supply oxygen and nutrients and absrobe carbon dioxide and waste
What are venules describe it’s adaptations as well as change in pressure and rate of blood flow
- small veins that converge forming larger venules and eventually veins
- similar structure to veins and as they widern resistance to blood flow decreaes allowing blood rate of flow to increase again
What are the function of veins it’s adaptation as well as change in pressure and rate of blood flow
- they carry blood back to the heart
- semi lunar valves prevent backflow of blood ensuring blood travels in one direction only
- although pressure in veins is low blood is returned to the heart due to the effects of surroudning skeletal muscle contracting squeezing the vein reducing the volume increasing pressure inside the vein forces blood through the valves
Describe the blood flow through the heart
- blood enters the heart from the head and body via the vena cava in the right atrium
- the right atrium contracts (atrial systole) forcing blood through the right atrio ventricular valve into the right ventrile which is relaxed
- the right ventricle contracts (ventricular systole) forcing blood out of the heart through the right semi lunar valve to the lungs via the pulmonary artery
- oxygenated blood returns from the lungs to the heart via pulmonary vein and enters the left atrium when the left atrium is relaxed (total diastole)
- the left atrium contract forcing blood through the left atrio ventricular valve into the left ventricle which is relaxed
- the left ventricle contracts forcing blood out through the left semi lunar vavle into the aorta and then to the rest of the body
systole
contraction