2.3 a - Adaptations for transport in animals Flashcards
Features of a transport system
suitable medium to carry materials ( blood)
pump for moving the blood
valves - to prevent backflow of blood
(unidirectional blood flow(
Respiratory pigment ( in vertebrates) but not in insects
a system of vessels, arteries, veins + capillaries
Open circulatory system?
blood does not move in vessels but the tissues bathe directly in a haemocoel
( cavity filled with blood)
has long dorsal tube shaped heart
runs the entire length of a body
pumps blood at low pressure into the haemocoel materials are exchanged ( co2 + O2) between blood and body cells
blood slowly to the heart
(not efficient)
O2 diffuses directly to the tissues to the spiracles (inwards) and tracheoles (outwards)
Closed circulatory system?
Blood moves in vessels
2 types single and double
single - blood moves through heart once for example fish
ventricle of heart pumps deoxygenated blood to the gills
pressure falls
oxygenated blood carried to the tissues and deoxygenated returns to the atrium of the heart
not an efficient system
wait for blood to leave then come back
Double circulatory system?
blood passed through the heart twice in a complex circuit
mammals have a closed double circulatory system
a muscular heart under high pressure pumps blood rapidly through the vessel
organs = not in direct contact with the blood
but are bathed in tissue fluid ( glucose + oxygen)
passed into cells becoming CO2 + waste
Blood pigment = haemoglobin
Why is blood returned to the heart?
blood pressure is reduced in the lungs and wouldn’t be high enough to circulate through the rest of the body instead, blood = returned to the heart to raise its pressure, before being pumped to the body
Pulmonary?
right side of the heart pumps deoxygenated blood to the lungs via the pulmonary artery
oxygenated blood returns from the lungs to the left side of the heart
Systematic?
left sided of the heart pumps oxygenated blood to the tissues via the aorta
deoxygenated blood from body returns to the left side of the heart
In each circuit?
blood passes through the heart twice once on right and once on the left
Structure + function of blood vessels?
arteries + veins have 3 layered structure
proportions = different
inner most layer
endothelium
1 cell thick
surrounded by tunica intima - smooth , reduces friction
minimum resistance to blood flow
middle layer = tunica media contains smooth muscle + elastic fibres
In artery, tunica media is thicker sa contains more elastic fibres to accommodate blood flow at high pressure
when elastic tissue stretches, it recoils and can be felt as a pulse
when smooth muscle contracts, it regulates blood flow
outer layer, tunica externa - contains collagen fibres to resist stretching
Length of artery?
10mm - 1cm
Length of vein?
6 mm
length of capillary?
0.02 mm
Function of artery?
carry blood away from the heart
thick muscular wall withstand pressure
arteries branch into arterioles which subdivide into capillaries
Function of vein?
has a large lumen
thinner walls with less muscle
lower pressure + flow rate
veins above the heart rely on gravity to return the blood to the heart
veins below the heart are reliant on traction of muscles to pump blood back to the heart if no movement occurs, blood pools, causing deep vein thrombosis
function of capillaries?
forms a vast network which penetrates all tissues
blood from capillary collects in venules and is transferred to veins before returning to heart
Structure of capillaries?
thin walls with one layer of endothelium cells on a basement membrane
there are pores between the cells that make the capillary walls permeable to water and solutes
capillaries have a smaller diameter which decreases flowrate
decreasing flow rate facilitates exchange of materials with tissue fluids
The heart has 2 pumps?
1 - systematic
1 - pulmonary
What’s the difference between them?
one deals with oxygenated blood whilst the other deals with deoxygenated
What’s the structure?
2 atria
thin-walled chamber
2 ventricles - thick-walled pumping chambers to separate oxygenated from deoxygenated blood
What is the heart made of?
made of cardiac muscle
myogenic
What is the structure and properties of the heart?
between skeletal and smooth muscle
cells have stripes but lack long fibers
contracts rhythmically without nervous stimulation or hormonal control
Myogenic def?
never tires
What happens during embryonic development in mammals?
the 2 separate pumps grow together to form 1 overall structure
Cardiac cycle def?
the sequence of events in one heartbeat which lasts 0.08s in an adult
consists of 2 alternating contractions which are
systole
diastole
What are the 3 stages?
atrial systole
ventricular systole
diastole
Atrial systole?
atrial walls contract
blood pressure increases
blood forces the tricuspid and bicuspid valves to open, and blood flows into the ventricles
tri?
right
bi?
left
Ventricular systole?
ventricle walls contract
blood pressure increases
blood = forced upwards through the semi-lunar valves ( crescent moon-shaped)
forced through semi-lunar valves to the pulmonary artery + and the rest of the body
Pulmonary artery?
only artery
carries deoxygented blood
blood cannot flow backwards
valves prevent backflow of blood
Aorta?
only artery that has valves
preventing backflow of blood
What does a rise in ventricular pressure cause?
tricuspid + bicuspid valves to close
Diastole?
ventricles relax
volume increases
pressure decreases
which would cause backflow - pressure’s drops
prevented by the semi lunar valves
atria relac, allowing blood from vena cava + pulmonary veins enters atria
Blood moving through the heart?
1)left atrium relaxes to receive oxygenated blood from the pulmonary vein
2) when atria = full, pressure forces bicuspid valve open
3) left ventricle relaxes, allowing blood to flow from the atrium
4) left atrium contracts, expelling remaining blood
5)left atrium relaxes + bicuspid valve closes
left ventricle contracts due to strong muscular wall which exerts high pressure
6) pressure pushes blood out of the heart through the semi lunar valves into the aorta
bicuspid closes to prevent backflow of blood
Summary?
2 sides of the heart simultaenously
Atria contracts almost at the same time
Ventricles contract milliseconds later
heart beat is 1 complete contraction and relaxation
sound made by a beating heart =lub dub created by the atrioventricular valves and the semi lunar valves
if chamber = contracting, its emptying
if chamber = relaxing,its filling
left ventricle = thicker than right, muscular to pump blood around the body
semi lunar valves close under high pressure - due to the contraction
SAN? ( sino arial node
area of the heart muscle in the right atrium that initiates a wave of electrical excitation across the atria to generate contraction of the heart muscle known as a pacemaker
AVN?
atrioventricular node
right in the septum of the heart
SAN?
cluster of specialised cardiac cells from which a wave of excitation spreads over both atris so they contract almost simultaneously
Ventricles?
insulated from the atria by a thin layer of connective tissue
Only at the AVN?
allows conduction as there is no connective tissue in it
creates a delay between atrial and ventricular contractions
allows the muscles of the atria to finish contracting before the muscles of the ventricle contract
What does AVN pass?
excitation down the septum which contains nerve fibres in the bundle of His until the apex of the heart is reached
excitation is transmitted to purkinje fibres which carry the impulse up and the ventricles contract simultaneously
blood is forced into the aorta and the pulmonary artery
ECG?
electrocardiogram
difference in charge
trace of voltage changes
P wave?
voltage change generated by the SAN
( contraction of atria)
( only small )
( not height peak)
aria have less muscle than ventricles so p = small
PR interval?
time taken for excitation to spread from the atria to the ventricles through the AVN
QRS?
Depolarisation + contraction of the ventricles
ventricles have more muscle so amplitude of the wave = greater
T wave?
repolarization of ventricle muscles
isoelectric line = baseline of the trace
Analysing an ECG?
heart rate can be calculated from the trace by reading the horizontal axis
If person has an atrial fibrillation
( rapid heart beat )
lack of a P wave
a person having a heart attack has a wide QRS complex
Person with enlarged ventricles - QRS complex has a greater voltage change
Person with blocked coronary arteries or atherosclerosis
change in the height of the T wave and the ST segment
Calculating heartbeat?
find difference between times
1.15 - 0.3
0.85
bpm = 60/0.85 = 71 bpm
Where is the blood pressure the highest?
highest in aorta + larger arteries
( rises + falls rhymthically with ventricular contraction)
Why is there a drop in pressure?
friction between blood + the walls of the vessels causes a progressive drop in pressure, especially in arterioles + capillaries due to large surface area
Where is blood pressure the lowest?
reduced in capillary beds as fluid leaks from the capillaries to the tissues
As distance from heart increases, the blood pressure decreases + the speed of veins do not experience pressure changes as they are not affected by ventricular attraction
In veins?
pressure is always low as it has a wide lumen
blood returns to the heart by massaging effect of muscles on the veins
Blood composiiton?
blood is a tissue made of cells ( 45 % )
other 55 % = plasma
Red blood cells?
erthyrocytes
contain haemoglobin to transport oxygen - pigment
from lungs to respiring tissue
biconcave shape - dip in middle
increases surface area for diffusion
has a thin centre which makes them look pale in the middle
makes diffusion faster
no nucleus - has been pushed out as it matures
this maximises oxygen transport
White blood cells?
leukocytes
larger than erythrocytes
2 types
granulocytes
have granular cytoplasm + lobed nuclei
phagocytic - eats stuff/inhales
Agranulocytes?
have a granular cytoplasm / no grams
clear
nucleus = spherical
non phagocytic
produce antibodies + antitoxins
Plasma?
pale yellow liquid
90 % water
contains glucose, amino acids, vitamin B, vitamin C, minerals, water HCO3, hormones and plasma proteins
Albumin + blood clotting proteins
Main purpose of plasma?
to distribute heat
Transportation of Oxygen equation?
Oxygen + haemoglobin — Oxyhaemoglobin
4O2 + Hb —– Hb —- Hb.4O2
Affinity def?
the degree to which 2 molecules are attracted to each other
What does affinity actually mean?
haemoglobin can change its affinity for oxygen by changing its shape
Hb - readily associates with oxygen in the alveoli
Disassociates from oxygen in respiring tissues
( muscle)
Co-operative binding def?
the increasing ease with which Hb binds to the second and third oxygen molecule as Hb changes shape
Structure of Hb?
each Hb molecule has 4 haem groups, each one has Fe2+
Oxygen can bind to each iron ion
1st O2 attaches + changes the shape of Hb to make it easier for the second to attach
the 2nd O2 molecule changes the shape for the third to attach
the third does not induce a shape change, so the partial pressure of O2 must increase significantly to bind the 4th
Partial pressure def?
concentration of O2 in one place
Normal atmospheric pressure?
100 kPa
Partial pressure of Oxygen?
21 kPa - 21% in the air when Hb - exposed to increase partial pressure, the graph would appear to be linear
( not actually linear )
(would have been if picked up the same way for each one
What shape graph does co-operatives binding produce?
a sigmoid curve graph
Stages 1,2,3 and 4 meaning?
1)difficult to load O2
2+3)O2 binding = easier
4)only occurs at high partial pressures
Adult haemoglobin?
oxygen affinity of haemoglobin is high at higher partial pressures of oxygen
Oxyhaemoglobin does not release oxygen at high partial pressures of oxygen
oxygen affinity decrease as the partial pressure decreases instead of Oxygen is released to meet the respiratory demand
Respiratory demand?
relationship between oxygen partial pressure + saturation of oxygen
not linear
Where do red blood cells load oxygen?
in the lungs where the oxygen pressure is high
Hb?
saturated with oxygen
Cells?
carry oxygen but in the form of oxyhaemoglobin to respiring tissues such as muscle
Muscle tissue?
a low partial pressure caused in respiration
when oxyhaemoglobin unloads oxygen
it disassociate
Equation for it?
Hb.4O2 —– Hb+4O2
splits in the haemoglobin + oxygen
Foetal haemoglobin
Hb of a foetus must absorb oxygen from maternal haemoglobin at the placenta
foetus has haemoglobin which differs in 2 of the 4 polypeptides 2 alpha and 2 delta instead of 2 alpha and 2 beta
What does this do?
gives a greater affinity of oxygen
at the placenta, blood flow of the mother + the foetus are close but never mixed
How is oxygen transferred?
to the foetus but the % saturation of the foetus = higher than the mothers so oxygen disassociated curve shifts to the left
How much oxygen is released and taken in?
21% of 02 = taken in by the moher
16% is released
5% of circulating
Worms?
lug worms live head down in the burrow
In the sand on the shore in a low oxygen environment
Low metabolic rate
Low Oxygen requirement
Haemoglobin loads Oxygen readily as it has a high affinity for oxygen
curb is to the left of the adult
Llamas?
live at high altitude where there is a low partial pressure of oxygen and haemoglobin has a higher affinity so curve is to the left of the foetus
myoglobin is further to the left
Seal?
has 8 alpha helicases in the myoglobin
The bohr effect def?
movement of the oxygen disassociation curve to the right at high partial pressure of Carbon dioxide because at a given oxygen partial pressure
Haemoglobin - lower affinity for oxygen
Effect of CO2 concentration?
If concentration increases, Haemoglobin releases Oxygen more readily
at any Oxygen, partial pressure Haemoglobin = less saturated with oxygen, so all data points on the curve is lower
Shifts in Graphs position?
the bohr effect + explains the unloading of oxygen from oxyhaemoglobin into respiring tissues where partial pressure of CO2 = high
Summary?
when Hb is exposed to an increase in Oxygen partial pressure, it absorbs Oxygen rapidly at low partial pressure but slowly as partial pressure increases
When Oxygen partial pressure is high in the lungs?
Oxygen combines with Hb to form Hb.4O2
When partial pressure of Oxygen is low
Oxygen disassociates from Hb.4O2
Chloride shift ( 9 marker)
Tissue fluid diagram labelled?
arteriole
blood capillary
venule
vein
lymph vessels which drain into thoracic duct
body cell
lymph capillary
artery
Why does pressure decrease?
due to large surface area of capillary bed
Tissue fluid def?
plasma without plasma proteins
too large to diffuse into the capillary
Structure of a capillary?
thin permeable walls
large surface area for exchange
blood flows very slowly to allow time for exchange of materials
Movement through the capillary wall?
fluid from the plasma = forced through the capillary wall as tissue fluid
What is tissue fluid used for?
bathes body cells supplying them with
glucose
amino acids
fatty acids
salt
hormones
oxygen
What does it do?
removes waste that is made by cells
for example CO2
What is diffusion reliant on?
on the hydrostatic pressure of the blood and its solute potential
Arterial end of the capillary bed?
blood is under high pressure due to the pumping of the heart
artery + arteriole walls shows muscular contraction
high hydrostatic pressure forces tissue fluid into the capillary
plasma has a low solute potential due to colloidal proteins
so water flows back into the capillary by osmosis
High hydrostatic pressure forces water and solutes into the body cells
Body cells metabolise using glucose and oxygen
so the concentration falls
Kwashiorkor?
protein deficiency
causes oedema
( swelling of cells with water)
Venus end of capillary bed?
Hydrostatic pressure - low because fluid has been lost so plasma proteins = more concentrated in the blood because water has been moved into the body cells
Solute potential of the remaining plasma is more negative, pulling water back into the capillary by osmosis
tissue fluid around the cells picks up CO2 + diffuses increase a concentration gradient into the capillary ( 90% ) + (10%) drains into the lymph vessel which is taken to the thoracic duct which empties into the subclavian vein
