Transport in animals SLOP Flashcards
describe 3 features of an effective transport system
- fluid to carry nutrients/oxygen/waste around the body
- a pump to create pressure that will push the fluid around the heart
- exchange surfaces (capillaries)
describe 3 disadvantages of single circulatory systems, as seen in fish
- blood pressure drops as blood passes through the gill capillaries
- blood flows slowly through as it is under low pressure
- rate of delivery of O2 to respiring tissues is limited (and removal of CO2 and urea)
explain why fish do not need as much energy as mammals
- not as metabolically active as they do not maintain their body temperature
what is open circulation
blood is not always held in vessels, but it circulates throughout the body cavity and the tissues and cells bath directly in blood
2 disadvantages of open circulatory systems
- blood pressure is low and blood flow is therefore slow
- circulation can be affected by body movements (or lack of)
state 3 advantages of closed circulation over open circulation
- blood travels at higher pressure = faster
- oxygen and nutrients supplied and CO2 removed more quickly
- transport is independent of body movements
what is the purpose of semilunar valves
to prevent back-flow of blood from the arteries to the ventricles
why is left ventricular wall thicker than the right wall?
blood is pumped through the aorta and needs sufficient pressure to overcome the resistance of the systemic circulation.
Pulmonary artery only carries blood to the lungs.
why are there so many mitochondria cells in the cardiac muscle
supply energy for muscles to contract
*what is the purpose of intercalated discs between adjacent muscle cells
ensures an even, synchronised contraction
briefly outline the events of atrial systole
- left and right atria contract together
- blood is squeezed from the atria through the atrioventricular valves unto the ventricles
(down a pressure gradient)
events of ventricular systole
ventricular blood pressure rises very quickly to a level above the arteries
- semilunar valves open and blood rushes out of ventricles into the arteries
outline the events of diastole
once ventricular contraction is complete, heart muscle starts to relax, heart fill with blood again and the semi lunar valves close
what does myogenic mean
cardiac muscle can initiate its own contractions
what tissue is responsible for initiating the heartbeat
Sinoatrial-node (SAN)
role of Atrioventricular-node (AVN)
tissue propagates the electrical signal form the atria to the ventricles, resulting in ventricular systole.
why is there a delay before the AVN depolarises the ventricular walls
to allow the atria to finish contracting
describe the role of the purkyne tissues
specially adapted muscle fibres that conduct a wave of excitation from the AVN down the septum to the ventricles
what do the letters in PQRST indicate in an ECG
P = atrial excitation
QRS = ventricular excitation
T = diastole
slow HR
brachycardia
*what happens in atrial fibrillation
atria beat more frequently than ventricle, meaning no clear p wave can be seen on ECG
what is an ectopic heart beat?
an early ventricular beat
fast HR
tachycardia
*what is the inner tissue lining of a blood vessel called? What is its role?
endothelium - reduced friction with the flowing blood
describe 3 structural layers of an artery
- tunica intima: thick layer of elastic tissue which allow walls to stretch and recoil (opposes muscle)
- tunica media: thick layer of smooth muscle
- tunica adventitia: thick layer of collagen and elastic tissue providing strength to withstand the high pressure and recoiling against the muscle.
what are the roles of an arteriole?
take blood from artery to capillary; they have a layer of smooth muscle which contracts restricting and slowing blood flow
describe how capillaries are adapted for exchange
-narrow lumen (squeezes red blood cells against walls so transfer of O2 is better to the tissues)
-walls consist of single layer of endothelial cells reducing diffusion distance
- walls are permeable which allows blood plasma and dissolved substances to leave the blood
describe function of a venule
takes blood from the capillaries to veins
*describe how veins are adapted to carry blood back to the heart
wide lumen to ease blood flow; thin layers of elastic/muscle/collagen in walls as no need to stretch and recoil; valves to prevent back flow of blood
where is hydrostatic pressure of the blood created
in the ventricles of the heart
what is oncotic pressure
the pressure created by the osmotic effects of solutes
what substances might affect the oncotic pressure of the blood
dissolved solutes such as mineral ions, sugars and proteins
state cell types most likely to be found in blood plasma, tissue fluid and lymph
blood plasma - RBCs, Neutrophils, lymphocytes
tissue fluid - neutrophils (especially during infection)
lymph - lymphocytes
why can’t proteins leave the blood plasma
too large to pass between squamous cells of capillary wall
why can neutrophils enter the tissue fluid but erythrocytes cannot?
neutrophils can change shape very easily due to multi lobed nucleus, and squeeze themselves between cells. Erythrocytes cannot change shape as much
*how does tissue fluid facilitate exchange of substances to body cells
tissue fluid surrounds body cells so exchange occurs across plasma membranes
describe the structure of haemoglobin
- four subunits (each with polypeptide chain and haem group)
- haem group each contain an Fe2+ ion at the centre, iron ions can attract and hold an oxy molecule
what is disassociation
oxyhemoglobin releases its oxygen to respiring cells
what is the main difference between foetal haemoglobin and adult haemoglobin
it has a higher affinity for oxygen than adult haemoglobin
describe 3 ways in which the CO2 is transported
5% dissolved directly in plasma
10% directly with HB in form of carbaminohaemoglobin
85% in form of hydrogen carbonate ions.
*describe the formation of hydrogen carbonate ions
CO2 from the blood plasma diffuses into the RBCs and combines with water to form carbonic acid (catalysed by carbonic anhydrase)
carbonic acid then disassociates into hydrogen carbonate ions and protons
*how is charge in a RBC maintained when hydrogencarbonate ions diffuse into plasma
chloride ions move into the RBC from the plasma = CHLORIDE SHIFT
describe how the pH inside an RBC is buffered as hydrogen ions build up inside, making RBC very acidic
hydrogen ions are taken out of solution and combined with haemoglobin to form haemoglobonic acid (HHb)
*what is the net result of bohr effect
more oxygen is released when more CO2 is produced in respiration
*With reference to protein structure, explain how increase hydrogen ion levels affects haemoglobin
more hydrogen ions = lower pH (more acidic cytoplasm)
tertiary structure of HB altered which reduces affinity for oxygen
HHb
haemoglobonic acid
how many polypeptide chains in haemoglobin
4
describe the role of the lymph fluid
a system of tubes that return excess tissue fluid to the blood stream.
