Transport in animals Flashcards
1
Q
What are features of a transport system
A
- suitable medium carry dissolved substances
- pump to move materials
- some systems (not insects) contain respiratory pigments (haeoglobin) that carries dissolved substances
- some use system of vessels with valves to enure one way flow to all parts of the body
2
Q
What are open circulatory systems
A
- blood does not move round the body in blood vessels
- cells bathed by blood or a fluid called haemolymph in a fluid filled space aorund organs called haemocel return slowly dosal - tubes shape hearts - insects
- no need for respiration pigment as oxygen is supplied firectly to tissue via tracheal sustem in insects
- it relatiley inefficient
- in insects not responsible for distribution of respiratory gases
3
Q
What are closed circulatory systems
A
- uses vessels blood transported more quicky under high pressure to all part of the body
- tow types - single or double circulation
4
Q
What are single circulatory systems
A
- blood passes through the heart once through passeage around the body
- fish blood pumped to gills on to the body organ before returning to the heart
- earthworm five pairs of ‘psuedoheartes’ (thickened muscular blood vessels) pump blood from dorsal vessel to ventral vessels
5
Q
What are double circulatory systems
A
- blood pass through the heart twice
- mammals involve one circuit which supplies lungs where blood is oxygenated - pulmonary circulation and second circuit supply blood body with oxygenated blood (systematic circulation)
- meets demands of mammals with high metabolic rate, higher blood pressure, faster circulation sustanined systematic ciculation and deoxygenated and oxygenated blood kep seperate and improve oxygen distribution
6
Q
Describe arteries
A
- thick walls resist high blood presure elastic fibres stetch to allow the arteries to accomodate blood and elastic recoil of fibres puhes blood along arteries
- pressure rythmic rise and fall corresponding to ventricular systole
- blood flows along arteries friction with vessel walls causes blood pressure and rate of blood flow to decrease
7
Q
Describe arterioles
A
- main arteries continually branch to form smaller arteries eventually arterioles
- large total surgace area and relativley narrow lumen causing further reduction in pressure and rate of blood flow
- smooth muscle tissure widen or narrow lumer to increase and decrease blood flow
8
Q
Describe capillaries
A
- millions of capillaries form dense network in tissues
- narrow lumen toal cross sectional area is very large
- as blood flow through both blood pressure and rate of blood flow decreases
- due to incressase in total cross sectional area and ficional resistqance of blood flowing along the blood vessels
- function is to supply oxygen and nutrients and absorb carbon dioxide and water
9
Q
Describe venules
A
- smaller veins converge forming venules and eventually veins
- similar structure to veins as they widen resistance to blood flow descreases aloowing blood rate to flow to increase again
10
Q
Describe veins
A
- carry blood back to the heart
- semi lunar valves prevent back flow of blood ensuring blood travels in one direction only
- pressure in veins is low blood is returned to the heart due to the effects of surrounding skeletal muscle contracting and squeexing the vein which reduces the volume and increases the pressure inide the vein forces blood through valve
11
Q
How does blood travel around the body
A
vena cava - > right atrium - right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta - > body
12
Q
How does blood flow through heart
A
- blood enters from heart from head and body via vena cava and into the right atrium
- right atrium contracts (atrial systole) forcing blood through right atrio ventricular valve in right ventricle which is relaxed
- right ventricle contracts (ventricular systole) force blood out of the heart through right semi lunar valve to lungs via pulmoary artery
- oxygenated blood return rom the lungs to the heart via pulmonary vein and enter the left atrium when ,eft atrium is relaxed (total diastole)
- left atrium contract forcing blood through left atrio ventricular valve into left ventricle which is relaxed
- left ventricle contracts forcing blood outhrough left semi lunar valve into aorta them to the rest of the body
- describes me circuit that blood take during the cardiac cycle both atria contract simultaneously followed by contraction of both ventricles
- valve ensure blood flows in unidirectional manner prevent backflow of blood
13
Q
Describe the cardiac cycle
A
- left atrium contracts so volume of atrium decreaes and pressure increases
- blood pressure in left atrium exceed that in left ventricle blood flows into left ventricle
- ventricle contracts (ventricular systole) and pressure rises in left ventricles as volume decreases
- ventricle contract blood pushed againt strio ventricular valves closing them preventing blood flow back into atria
- pressure in left ventricle excees aorta left semi lunar valves open vlood flows out into aorta
- left ventricle relaxes (diastole) so volume increases and pressure falls
- pressure in ventricle drops below aorta blood then flow back into ventricle from aorta pushing against left semi lunar valve and closing it
- pressur in left ventricle drop below in left atrium and left atrio ventricular opens cycle begins again
- blood flow from high to low pressure unless a valve prevents it
14
Q
What is a heartbeat
A
- heart in myogenic heartbeat is initiated within cardiac muscle itself and not dependent upon external stimulation
- however be regulated this is accomplished by sino atrial node initiate wave of excitation across both atria
15
Q
What is atrial systole
A
- wave of excitation spreads out from sino atrial node (SAN) across both atria
- both atria tart contracting
- wave cannot spread to ventricles due to layer of connective tissue
- wave spreads via the atrio ventircular node (AVN) through bundle of his to apex of ventricle