transport - circulatory system notes

TRANSPORT IN ANIMALS- CIRCULATORY SYSTEMS

Small animals don’t need a separate transport as the majority of things they need can be transported via diffusion. However large animals do as diffusion would be to slow. Three main reasons why large animals need a transport system are as followed:

Large animals have several layers of cells meaning O2 and nutrients wouldn’t reach the deep cells fast enough if the animal didn’t have a transport system.

Larger animals have a small surface area: volume ratio which means it’s not large enough to supply all the oxygen and nutrients needed by the internal cells

Bigger animals have higher levels of activity; releasing energy which needs to replaced quickly, only a transport system could do so – allowing a fast exchange of substances.

Good transport systems tend to have

Fluid to carry nutrients and oxygen around the body – in humans this is blood

A pump to create pressure – in humans this is the heart Exchange surfaces that enable O2 to enter/exit the blood when it’s needed. Tubes/ vessels to carry the blood 2 circuits to pick up O2 and the other to deliver O2 to the tissues

SINGLE CIRCULATORY SYSTEMS

A single circulatory system is closed. Blood flows like a tide between the heart, body and gills then back again. It’s most commonly found in fish. There isn’t a division of systemic and pulmonary like in a double circulatory system.

ADVANTAGES – It doesn’t waste energy.DISADVANTAGES- it’s at low pressure doesn’t pump as fast. The oxygen rich and poor blood mix.

DOUBLE CIRCULATORY SYSTEMA double circulatory system is closed. It has two routes. These are systemic (to the lungs) and pulmonary (to the body) It goes through the heart twice – like having two pumps. The heart has four chambers. Most vertebrates such as birds and humans have a double circulatory system.

ADVANTAGES- blood flow can be controlled by the heart. The pressure is high and is maintained. Constant strong supplies, oxygen rich and oxygen poor blood are separated. DISADVANTAGES – complex system with a danger of clotting, heart attack, failing valves, bleeding out

OPEN CIRCULATORY SYSTEMFluid flows freely through the body cavity. It’s found mainly in small animals such as ARACHNIDAS, INSECTAS and CRUSTACEAE. It doesn’t maintain pressure and provide much O2 but provide nutrients and occasional O2. It has muscular pumping organs. Blood from the body enters the heart through pores called OSTIA. The heart pumps blood to the head via PERISTALIS.


ADVANTAGES- less vulnerable to pressure, have control over body temperature which allows them to survive in extreme conditions – hot and cold. Less complex reducing risks of clotting and bleeding out. DISADVANTAGES- Low metabolic rates, it’s also hard to rise and lower the velocity of blood flow.

CLOSED CIRCULATORY SYSTEMThe fluid is enclosed in tubes such as arteries and capillaries. The closed circulatory system has a pump. All vertebrates have a closed circulatory system. Also ANNELIDS and CAPHALOPODS have them.

ADVANTAGES- maintains pressure, has control over O2 delivery to tissuesDISADVANTAGES- more complex, blood clotting, valve failure, bleeding out, too high/low pressure

and failing organs are all problems with the closed circulatory system.

LORD – left oxygenated, right deoxygenated. In the heart there are tendious cords which prevent the valves been flimsy. Septum separates oxygen rich/poor blood.

Exterior view – Coronary arteries provide the heart muscle itself with oxygenated blood. These are very important. When these become blocked with fatty deposits it can lead to heart attacks and angina.


Each chamber of the heart has different muscle thicknesses. Left Ventricle – This has thickest muscle. It’s thicker than the right ventricle as it requires a powerful contraction to force the blood around the whole body at a high pressure.

Right Ventricle – Second thickest muscle. Thicker than the atria as it has to have an increased contraction to pump the blood to the lungs. With some pressure. Still pressure must be kept down to prevent bursting any of the smaller capillaries in the lungs that can’t withstand a high pressure.

Atria- Both the Right atrium and left atrium have thin muscular walls this is because the contraction doesn’t need to be strong as the blood is only transported a small distance into the adjacent ventricles.

CARDIAC CYCLE

CARDIAC CYCLE IS THE SEQUENCE OF EVENTS DURING ONE HEARTBEAT

DIASTOLE = WHEN THINGS RELAX: SYSTOLE = WHEN THINGS CONTRACT

DIASTOLE IS THE START OF THE CYCLE.

1) DIASTOLEDiastole is the filling stage. Both the atria and ventricles are relaxed. Blood is flowing in both and through the open atrioventricular valves. The pressure and volume in both are gradually rising.

2) ATRIAL SYSTOLEThe heartbeat starts when the atria contract -both the right and left atria contract together. The atria have a small contraction which forces blood into the ventricles through the already open

Valves open/ close depending

on pressure of the blood.


atrioventricular valves. This stretched the walls of the ventricles ensuring they are full of blood. Contraction of the atria is known as atrial systole. Once the ventricles are full of blood, blood flows back into the valve pockets causing them to snap shut. The pressure in the ventricles is now higher than that in the atria. The closed atrioventricular valves stop any backflow. The closing of the valves gives a lub sound.

3) VENTRICULAR SYSTOLEThere is a very short period where all 4 valves are closed. The ventricles which are full of blood contract, causing pressure in ventricles to rise very quickly. This contraction starts at the apex so blood is pushed upwards into the arteries. The pressure in the ventricles is higher than the pressure in the arteries so the semi lunar valves are forces open and blood is spurted out under great pressure. This only lasts for a short amount of time. When the ventricle starts relaxing – the pressure drops and the semi lunar valves close. The heart then starts refilling and the cycle starts again.

Valves – SEMILUNAR VALVES and ATRIOVENTRICULAR VALVES.

Semi-lunar valves- when the ventricle contracts, the pressure in the arteries is higher than in the ventricles so the semi-lunar valves are closed. As the ventricle contracts the pressure inside rises very quickly because blood can’t escape. Once pressure in ventricle rises above pressure in arteries the semi-lunar valves are pushed open, the blood is under high pressure so spurts out.

When the ventricle is finished contracting, the heart muscle starts to relax, elastic tissues in the walls of the ventricle start to recoil and the ventricle returns to its normal size. Pressure in the ventricle drops very quickly – the pressure drops below the pressure in the major arteries so the semi-lunar valves close due to the valve pockets been full of blood. This causes and “dub” sound. This also prevents any backflow.


Atrioventricular valves- When the ventricle walls relax and recoil after contracting the pressure in the ventricle the pressure in the ventricle drops below the pressure in the atria. So the atrioventricular valves open. These open valves allow blood to flow straight through the atria and ventricle during heart diastole. The pressure and volume in both the atria and ventricle slowly starts to rise as they fill with blood. As the atria contracts the atrioventricular valves remain open.

As ventricle contracts, the pressure in the ventricle rises above the pressure in atria, so blood moves upwards the valve pockets are then filled with blood and the atrioventricular valves are closed, preventing backflow and making a loud “lup” sound as they close.

HEART MUSCLE IS MYOGENIC – it contracts without receiving signals from nerves.

The wave of excitation starts as the SAN. The SAN acts as a pacemaker as it sends out the waves of electrical activity (wave of excitation). It does this usually about 55-80 times per minute. It initially sends the wave of excitation across the atrial walls causing them to simultaneously contract. This causes atrial systole. A band of non conductive collagen prevents the wave of excitation been passed straight down into the ventricle walls. Instead the SAN passes the wave of excitation onto the AVN.

The AVN then holds “delays” the wave of excitation, before reacting. It does this to allow the ventricles to full with blood and ensure the atria have finished contracting. The AVN then passes the wave of excitation onto the bundle of his.

The Bundle of His is a group of muscle fibres responsible for passing the wave of excitation onto smaller, finer muscle fibres in the right and left ventricle walls known as the purkyne fibres.


The purkyne fibres then carry the wave of excitation into the muscular walls of the right and left ventricles causing them to contract from the apex upwards simultaneously. This causes ventricular systole. This also allows the blood to be forced upwards. The wave then starts again back at the SAN

ELECTROCARDIOGRAMS

An ECG is a machine that can monitor the heart. It produces a trace of which doctors can compare with a model trace to detect and defects such as abnormalities, faulty valves, heart attacks, ARRHTMIA- an irregular heart beat and FIBRILLATION- uncoordinated heart beat

The machine records the electrical activity of the heart; it’s done by placing electrodes on the chest of the person undergoing the test. The heart depolarizes when it contracts and depolarizes when it relaxes, these changes in electrical charges produce the trace. Underneath is a model ECG trace.

P wave = electrical impulse from SAN spreading over the atria. It is the impulses over the atria, here the volume of the atria is higher (valves are and remain open) than the ventricle so atria contracts pushing blood onwards.

QRS wave = wave of excitation passing over the bundle of his and into the purkyne fibres. Here the ventricle pressure is higher than the arteries so the semi lunar valves are forced open pushing blood upwards.

T wave= electrical recovery before next impulse. Here the ventricle relaxes and recoils back to original shape the semi-lunar valves close. The pressure in ventricle drops below that of atria so atrioventricular valves open however the whole heart is still in diastole. The pressure in the atria is slowly rising preparing for the next wave of excitation.

T

S

P

Q

R


ECG can calculate how many heart beats per minute. Don’t forget to use units when measuring this.

ABNORMAL ECG’S CAN DETECT HEART DEFECTS SUCH AS THE FOLLOWING ONES:

ARTERIES, VEINS and CAPILLARIES

ARTERIES VEIN CAPILLARIES

Take blood away from the heart. This blood is at high pressure so they have to

Carry blood back to the heart

At low pressure so walls

Very thin walls for exchange of materials such as oxygen


withstand it. They have a small lumen to

maintain high pressure They have thick collagen walls

for strength. Elastic fibres to allow the wall

to stretch and recoil when heart pumps.

Recoil maintains high pressure when heart relaxes

They have smooth muscle that can contract/constrict the artery and can narrow the lumen

Has a folded endothelium which can unfold as the artery stretches.

don’t need to be thick Large lumen to allow

easy blood flow Thinner layers of

collagen, smooth muscle and elastic as they don’t need to stretch and recoil.

Aren’t actively constricted to reduce blood flow

Have valves to prevent backflow

As they’re thin they can be flattened by skeletal muscle

Pressure is applied to the blood forcing it along in the right direction.

Single layer of flattened cells that reduce the diffusion distance

Lack of smooth muscle and collagen makes them not very strong

Narrow lumen allows the blood to be squeezed which pushed it close to capillaries which in turn reduces the diffusion distance for substances to the tissues.

TISSUE FLUID

Tissue fluid is similar to blood, however it doesn’t contain most of the cells and plasma proteins found in the blood. It’s role is to transport O2 and nutrients from blood to cells and carry CO2 and H2O back to the blood. It’s fluid that surrounds cells in tissues.

How is it formed?

In a capillary bed, substances move out of the capillary into the tissue fluid by pressure filtration. As the start of the capillary, nearest to the arteries, the pressure inside the capillaries is greater than the pressure in the tissue fluid. This higher pressure is caused by contraction of the heart muscle. This pressure difference forces fluid out of the capillaries into spaces around cells- this is HYDROSTATIC PRESSURE”- forming tissue fluid. The fluid that leaves consists of plasma and dissolved substances but other components such as red blood cells are too big to fit through the gaps.

How it returns?

As fluid leaves the pressure reduces in the capillaries, so the pressure is much lower in the end of the capillary bed nearest the veins. Due to this fluid loss, the water potential at the end of the capillaries nearest the veins is lower than the water potential in the tissue fluid. So some water re-enters the capillaries from the tissue fluid at the vein end, down the potential gradient, via osmosis. This tissue fluid contains water and carbon dioxide.


Not all tissue fluid re-enters the capillaries, about 90% of the fluid which leaks out of the capillaries seeps back in, the remaining 10% is returned to the blood by the lymphatic system and is called lymph. it returns to the blood via the lymphatic system. This is a drainage system made up of lymph vessels. This system is made up of many blind-ending lymph vessels, which allow tissue fluid to flow into them via one way valves. These valves are large enough to allow proteins, which are too big to get into the capillaries, into the lymph vessels. Lymph fluid is similar to tissue fluid; it has the same solutes but less nutrients and O2 and more CO2 and waste. It also has more fatty material which it has absorbed from the liver.

Smallest lymph vessels are known as the lymph capillaries Excess tissue fluid passes into the lymph vessels. Once inside it’s called lymph Valves in the lymph vessels stop lymph going backwards. Lymph gradually moves towards main lymph vessel in the thorax. Here it’s returned to the blood

near the heart.

The lymph has lymphocytes, these are produced in swellings along the lymphatic system (lymph nodes) there job is to filter and bacteria or foreign particles from the lymph fluid then destroy/engulf them. It is a major part of the immune system.

Blood, tissue fluid and lymph fluid all have similarities and differences. Shown in the table below:


FEATURE BLOOD TISSUE FLUID LYMPH FLUIDRed blood cells YES NO NOWhite blood cells YES YES –(VERY FEW) YES –( LYMPOCHYTES)Fat YES – (LIPOPROTIENS) NO YESWater YES YES YESPlatelets YES NO NOGlucose YES – (80-120MG PER 100CM3 YES -(LESS) YES - (LESS)Proteins YES – (HORMONES/PLAMSA PROTIENS) YES- (HORMONES) YES- (ONLY ANTIBODIES)O2 YES YES (LESS) YES -(LESS)CO2 YES – (VERY LITTLE) YES- (LESS) YES – (MORE)Dissolved Substances

YES YES YES

CARRIAGE OF OXYGEN

O2 is carried in red blood cells bound to the protein haemoglobin. There are over 300 million haemoglobin molecules.

One haemoglobin molecule has FOUR POLYPEPTIDE CHAINS, with a HAEM GROUP at the centre of each of them. Each haem group has one iron atom and for every iron atom, one oxygen molecule binds to it. Meaning for each haemoglobin molecule. 4 O2’s can be carried – a total of 8. This gives 4 binding steps. Te reaction is reversible. Oxygen drives the reaction to the right and hydrogen drives the reaction to the left.

As the two different saturation are different colours, it’s easy to measure % of saturation of blood in a COLORIMETER. As the equation shows O2 drives the equation to the right, so the more 02 in the surrounding, the more saturated the haemogolbin will be.

The term “PARTIAL PRESSURE” of oxygen doesn’t mean the pressure of the blood itself. It is a measure of the concentration of oxygen. It is written in shorthand as pO2 and is measured in kilopascals (kPa).


Inhaled air in the alveoli has a pO2 = 14kPa. The pO2 of resting tissue = 5.3kPa (lower pO2 = lower O2concentration due to respiration) and the pO2 of active tissues = 2.7kPa. In either case, blood arriving at the lungs has a lower pO2 than that in the lungs. There is therefore a diffusion gradient and oxygen will move from the alveoli into the blood. The O2 is then loaded onto the Hb until the blood is about 96% saturated with oxygen. The Hb is now called oxyhaemoglobin (HbO2). The concentration of O2 in the surrounding can be measured as a % but it’s more correct to measure it as a partial pressure: 20% oxygen in area= PO2 of 20kPa. This is the same for C02

Haemogolbins affinity for O2 depends on the partial pressure of O2. O2 loads onto haemoglobin to form oxyhaemoglobin where there’s a high PO2 and unloads where there is a low PO2. O2 enters at the alveoli where there is a high PO2, do oxygen loads onto haemoglobin. When cells respire they use up O2 so there’s a lower PO2- so blood unloads its oxygen. It then returns to the lungs to reload.

DISSOCIATION CURVES

The graph has an “S” shape and shows the features of O2 transport.

In alveoli, there is a constant supply of 02 so its concentration is kept high – about 14kPa. As blood passes through haemoglobin binds to O2 and becomes almost 100% saturated. This triggers a change in shape of

the molecule, which allows subsequent molecules to be taken up more readily. Once it gets to a certain point – no more can be taken up. This is when the graph has a straight section around the 95% saturation point.

In tissues like the brain and liver, O2 is used up by respiration, so it’s concentration is low, 4kPa. At this point the haemoglobin is only 50% saturated – so it unloads ½ it O2 to cells which will use it to respire

In tissues that are respiring quickly, such as muscle, the PO2 drops even lower to about 2kPa, so haemoglobin saturation drops to about 10%, so even more O2 (about 90%) is unloaded, providing more oxygen and energy for the fast respiring cells.


Actively respiring tissues also produce a lot of CO2, which dissolves in the tissue fluid to make carbonic acid, and so lowers the pH. H+ ions drive the equation (shown before) to the left, so low pH reduces the % saturation of haemoglobin and PO2. This is shown by a dotted line which is lower than the normal dissociation curve – this downwards shift is known as the “BOHR SHIFT” after the Danish scientist that discovered it. The amount of O2 carried and released by Hb depends not only on the pO2 but also on pH. An acidic environment causes HbO2 to dissociate (unload) to release the O2 to the tissues. Just a small decrease in the pH results in a large decrease in the percentage saturation of the blood with O2. Acidity depends on the concentration of hydrogen ions. H+ displaces O2 from the HbO2, thus increasing the O2 available to the respiring tissues.

H+ + HbO2 → HHb + O2

HHb is called haemoglobinic acid. This means that the Hb mops up free H+. That way the Hb helps to maintain the almost neutral pH of the blood. Hb acts as a buffer. This release of O2 when the pH is low (even if the pO2 is relatively high) is called the Bohr Effect.

When does the pH decrease because of free H+ in the blood?During respiration, CO2 is produced. This diffuses into the blood plasma and into the red blood cells. Inside the red blood cells are many molecules of an enzyme called carbonic anhydrase. It catalyses the reaction between CO2 and H2O. The resulting carbonic acid then dissociates into HCO3− + H+. (Both reactions are reversible.)

CO2 + H2O → H2CO3 Carbon dioxide water carbonic acid H2CO3 → HCO3− + H+ Carbonic acid hydrogen carbonate ion hydrogen ion

Therefore, the more CO2, the more the dissociation curve shifts to the right:


CARBON DIOXIDECarbon dioxide concentration also affects O2 unloading. Haemoglobin gives up O2 more readily at higher partial pressures of CO2. This is too get more O2 into the cells during activity. When these cells respire they produce CO2 which raises the PCO2, increasing the rate of O2 unloading.

Most of the CO2, from respiring tissues diffuses into the red blood cells and is converted into carbonic acid by the enzyme carbonic anhydrase.

This carbonic acid then split up to give hydrogen ions and hydrogen carbonates ions. This increase in H+ ions causes oxyhaemoglobin to unload its O2 so that the

haemogolbin can take up these H+ ions to form a compound called HAEMOGOBINIC ACID.

The hydrogen carbonate ions diffuse out of the red blood cells and are transported in the blood plasma.

When blood reaches the lungs, the low PCO2 cause hydrogen ions and carbonates to recombine into CO2.

This then diffuses into the alveoli and is breathed out.

CARRIAGE OF CARBON DIOXIDE

Carbon dioxide is carried in three ways, and is carried between respiring tissues and lungs.

As dissolved gas in blood plasma (2%) Very little travels this way as CO2 isn’t very soluble in water.

As carbamino haemoglobin (13% CO2 binds to amino acid in haemoglobin molecules, since there are so many haemoglobin molecules in red blood cells, and each one has many amino groups, quite a lot of CO2 can be carried this way.

As Hydrogen Carbonate Ions (85%) The CO2 reacts with H2O to form Carbonic acid which immediately dissociated to form Hydrogen Carbonate Ions and protons. The proton binds to haemoglobin causing the Bohr shift. Hydrogen carbonate is very soluble, so most CO2 is carried this way. The reaction is H2O is very slow but res blood cells contain the enzyme CARBONIC ANHYDRASE, which is a catalyst which makes it 108x faster.In respiring tissues CO2 produced by respiration diffuses in blood cells and forms hydrogen carbonate, which diffuses out of cell into the blood plasma through an ion channel in red blood cell membrane. The channel carries chloride ion into cell for every hydrogen ion it carries out – therefore keeping it constant.


FETAL HAEMOGLOBIN


F

Fetal haemoglobin has a higher affinity for oxygen at lower partial pressures, so it’s oxygen dissociation curve is shifted up to the left. A developing fetus gets it’s O2 from mothers blood. The mothers blood has a decreased saturation because it’s been used by the body. So for the fetus to get enough O2 to survive its haemoglobin has to have a higher affinity so it can take up 02. If they both had the same oxygen affinity the fetus wouldn’t receive enough oxygen.

A fetus’ haemoglobin is replaced by an adults during the first year of its life.

CIRCULATORY GLOSSARY

Single circulatory system: A single circulatory system is closed. Blood flows like a tide between the heart, body and gills then back again. It’s most commonly found in fish

Double circulatory system: A double circulatory system is closed. It has two routes. One from the heart to the lungs and one from the heart to the body. All vertebrates have these.

Open circulatory system: Fluid flows freely through the body cavity. It’s found mainly in small animals such as ARACHNIDAS, INSECTAS and CRUSTACEAE.

Closed circulatory system: The fluid is enclosed in tubes such as arteries and capillaries. The closed circulatory system has a pump. All vertebrates have a closed circulatory system.

Systemic: Is the route from the heart to the lungs in a double circulatory system.


Pulmonary: Is the route from the heart to the body in a double circulatory system.

Peristalis:. Is how the heart pumps blood to the head in an open circulatory system.

Ostia: are the pores that blood from the body enters the through to reach the heart in an open circulatory system.

Coronary arteries: Run over the exterior of the heart, and provide the heart muscle itself with oxygen, if blocked with fatty deposits then heart attacks and angina can occur with the person.

Left Ventricle: Has the thickest muscle in the whole heart, deals with oxygenated blood and is responsible for sending the blood up into the aorta.

Right Ventricle: Has the second thickest muscular walls in the heart, deals with deoxygenated blood and sends it to the lungs.

Atria: They are the receiving chambers, there is both Right and left and they send blood onto the ventricles.

Septum: Runs between the ventricles and separates deoxygenated and oxygenated blood.

Cardiac Cycle: Is the sequence of events during one heartbeat

Diastole: When the whole heart is relaxing

Atrial Systole: When the atria contract and force blood through the atrioventricular valves to the ventricles.

Ventricular Systole: When the ventricles contract and force blood through the semi-lunar valves to the arteries

Semi-lunar valves: Found before the arteries to prevent backflow. Open when ventricle contracts.

Myogenic: The heart muscle is Myogenic meaning is doesn’t require an impulse from a nerve to contract

Wave of excitation: The wave of electrical impulses that spread across the heart causing it to contract

SAN: the Sino-atrial node, acts as a pacemaker, releases the wave of excitation between 55-80 times a minute

AVN: Atrio-ventricular node, the wave of excitation is passed on from the SAN to the AVN, which delays it.

Bundle of His: The AVN passes the wave onto the bundle of his, group muscular fibres.


Purkyne fibres: The bundle of His passes it on to purkyne fibres, which are finer fibres which run through the muscular ventricle walls causing them to contract simultaneously from their apex upwards.

ECG: A machine that measures electrical activity of the heart, using electrodes places on the chest. These produce a trace, can detect any heart problems.

Fibrillation: an uncoordinated heart beat

Arrhythmia: an irregular heartbeat.

P wave: electrical impulse from SAN spreading over the atria.

QRS wave: wave of excitation passing over the bundle of his and into the purkyne fibres.

T wave: electrical recovery before next impulse.

Arteries: Take blood away from the heart; withstand great pressure, thick with collagen, small lumen

Veins: Take blood to the heart, large lumen, have valves

Capillaries: One cell thick for diffusion, branch of arterioles.

Tissue fluid: Tissue fluid is similar to blood, however it doesn’t contain most of the cells and plasma proteins found in the blood. It’s role is to transport O2 and nutrients from blood to cells and carry CO2 and H2O back to the blood. It’s fluid that surrounds cells in tissues

Hydrostatic Pressure: Water pressure, allows substances to move down the water potential gradient and enter/exit other things.

Pressure filtration: How substances move from the capillary bed to the tissue fluid.

Capillary bed: A group of capillaries.

Lymphatic system: a drainage basin for tissue fluid that hasn’t reentered the blood. Consists of lymph vessels.

Lymphocyte: there job is to filter and bacteria or foreign particles from the lymph fluid then destroy/engulf them. It is a major part of the immune system.

Lymph nodes: swellings along the lymph vessels that produce lymphocytes.

Four polypeptide chain: One haemoglobin molecule has FOUR POLYPEPTIDE CHAINS; these are chains of amino acids. Each one has a haem group at the centre.

Haem Group: A group at the centre of each polypeptide chain, with one iron atom which allows oxygen molecule to bind to it.

Colorimeter: A machine that can measure that % oxygen saturation of blood – using colour


Partial Pressure: The term “PARTIAL PRESSURE” of oxygen doesn’t mean the pressure of the blood itself. It is a measure of the concentration of oxygen. The percentage of oxygen in the surrounding, for example 20% oxygen in surrounding area = 20kPa.

pO2: The shorthand way of writing the partial pressure of oxygen

kPa: The measurement of the partial pressure of oxygen (kilopascals)

Ion Channel: allows hydrogen carbonate to diffuse out of cell into the blood plasma through an ion channel in red blood cell membrane. The channel carries chloride ion into cell for every hydrogen ion it carries out – therefore keeping it constant.

Fetal haemoglobin: A baby’s haemoglobin, it has a higher affinity for oxygen as opposed to adults.

Carriage of Carbon Dioxide: Carbon dioxide is carried in three ways, and is carried between respiring tissues and lungs. As Hydrogen Carbonate Ions (85%), as carbamino haemoglobin (13%) and As dissolved gas in blood plasma (2%)

transport - circulatory system notes

Documents

closed circulatory system

blood clotting

heart pumps blood

blood flows

large animals

oxygen poor blood

advantages blood flow

disadvantages complex