TRANSPORTATION OF MATERIALS IN LIVING THINGS
The Concept of Transportation of Materials in Living Things
The Concept of Transportation of Materials in Living Things
Explain the concept of transportation of materials in living things
Unicellular organisms (for example amoeba), nutrients (for example oxygen and food) and waste products (for example carbon dioxide) can simply diffuse into or out of the cells from the surroundings. But in multi cellular organisms (for example humans and trees), many cells are very far away from the body surface, hence a transport system is required for the exchange of materials.
Organisms require transport systems so as to carry out various life processes. These life processes include nutrition, respiration, excretion, growth and development, movement,reproduction and coordination. For these life processes to take place, transport of materials is inevitable. Materials are transported either from environment into the organisms or from one part of an organism to another, and can also be transported from an organism into the environment.
For example, during nutrition organisms take in food substances that they need to produce energy, grow and carry out other life processes. These food substances must be taken in from the environment. The same case applies to reproduction which requires the movement of gametes(sex cells) from the sex organs to the area where fertilization occurs. Therefore, transport is very important for the survival and existence of living things.
The Importance of Materials in Living Things
Outline the importance of materials in living things
Transport of materials is very important for the survival and development of living organisms. If transportation never existed, then no life on earth could be possible. The following is an outline of the importance of transport of materials in living things:
It facilitates the removal of waste materials from the organism’s body, the excess of which could harm an organism.
It ensures that essential materials like oxygen, nutrients, water, hormones and mineral salts are supplied to the cells and tissues as required.
It enables essential substances to move from one part of the body to another. For example,food manufactured by photosynthesis in plant leaves is transported from leaves to other organs of the plant for use or storage.
Diffusion, Osmosis and Mass- flow
The Meaning of Osmosis, Diffusion and Mass- Flow
Explain the meaning of osmosis, diffusion and mass- flow
Life processes in organisms take place at the cell level. Therefore, it is necessary for substances to move in and out of the cells. There are two ways through which substances can move across the membrane. Materials in living organisms move by diffusion, osmosis and mass flow.
two solutions with different concentrations; and
a partially permeable membrane to separate them.
A little dissolved salt produces a dilute solution with a high water concentration
A lot of dissolved salt produces a concentrated solution with a low water concentration.
Gaseous exchange in the lungs of animals and in the leaves of plants
Absorption of digested food in the ileumThe process of diffusion
Removal of west materials from cells
Absorption of nutrients and oxygen into cells
|It is the movement of all types of substancesfrom the area of their higher concentration tothe area of their lower concentration||It is the movement of only solvent or waterfrom the area of their higher concentration tothe area of their lower concentration through apartially permeable membrane|
|Diffusion can operate in any medium||Osmosis operates only in a liquid medium|
|Diffusion is applicable to all types ofsubsstances (soilds, liquids and gases)||It is applicable only to solvent part of asolution|
|It does not require any semi-permeablemembrane||A semi-permeable membrane is a must foroperation of osmosis|
|It is purely dependent upon the free energy ofthe diffusing substance||Osmosis is dependent upon the dregree ofreduction of free energy of one solvent overthat of another|
|It helps in equalizing the concentration of thediffusing substance througout the availablespace||It does not equalize the concentration ofsolvent on the two sides of the system|
|Turgor pressure or hydrostatic pressure doesnot normally operate in diffusion||Osmosis is oppossed by turgor or hydrostaticpressure of system|
|It is not influenced by solute potential||Osmosis is dependent upon the solute potential|
|Diffusion of a substance is mostly dependentof the presence of other sustances||It is dependent upon the number of particles ofother substances dissolved in a liquid|
|Factors like water potential, solute potentialand pressure potential do not affect diffusion||Factors like water potential, solute potentialand pressure potential affect osmosis in aliving system|
Through the process of osmosis, nutrients get transported to cells and waste materials getmoved out of them.
The pressure within and outside each cell is maintained by osmosis as this process ensures abalance of fluid volume on both sides of the cell wall. If fluid volume within a cell is morethan the fluid volume outside it, such pressure could lead the cell to become turgid andexplode. On the contrary, if fluid volume outside the cell is more than the fluid volumewithin, such pressure could lead the cell to cave in. Both cases would be detrimental tonormal and healthy cellular function.
It is via osmosis only that roots of plants are able to absorb moisture from the soil andtransport it upwards, towards the leaves to carry out photosynthesis. Plants wouldn’t existwithout osmosis; and without plants, no other life could exist as they are a vital link of theentire food chain of the planet.
Without osmosis, it would be impossible for our bodies to separate and expel toxic wastesand keep the bloodstream free from impurities. The process of blood purification is carriedout by the kidneys which isolate the impurities in the form of urine.
Therefore, the role of osmosis is twofold: it helps maintain a stable internal environment in aliving organism by keeping the pressure of intercellular and intracellular fluids balanced. It alsoallows the absorption of nutrients and expulsion of waste from various bodily organs on thecellular level. These are two of the most essential functions that a living organism cannot dowithout.
The right atrium links to the right ventricle by the tricuspid valve. This valve preventsbackflow of the blood into the atrium above, when the ventricle contracts.
The left atrium links to the left ventricle by the bicuspid valve. This valve also preventsbackflow of the blood into the atrium above, when the ventricle contracts.
Semi-lunar (pocket) valves are found in the blood vessels leaving the heart (pulmonary arteryand aorta). They only allow exit of blood from the heart through these vessels followingventricular contractions.
Ventricles have thicker muscular walls than atria. When each atrium contracts, it only needsto propel the blood a short distance into each ventricle while ventricles pump blood to distantbody parts.
The left ventricle has even thicker muscular walls than the right ventricle. The left ventricleneeds a more powerful contraction to propel blood to the systemic circulation (all of the bodyapart from the lungs). The right ventricle propels blood to the nearby lungs. So, thecontraction does not need to be so powerful.
The tricuspid valve; found between the right auricle and right ventricle
The bicuspid valve: found between left auricle and left ventricle
Semi-lunar valves which are located at the bases of the pulmonary artery and aorta to preventblood from flowing back into the ventricles.
|Part of the heart||Function|
|Aorta||The largest artery in the body; it conducts freshly oxygenated bloodfrom the heart to the tissues.|
|Superior vena cava||Large vein that brings deoxygenated blood from the upper parts ofthe body to the right atrium|
|Inferior vena cava||Large vein that brings deoxygenated blood from lower regions of thebody to right atrium|
|Pulmonary artery||Carries deoxygenated blood from the right ventricle to the lungs|
|Pulmonary vein||Blood vessel that carries oxygenated blood from the lungs to the leftatrium|
|Right atrium||This chamber of the heart receives deoxygenated blood from thebody (from the superior and inferior vena cava).|
|Left atrium||This chamber of the heart receives oxygenated blood from the lungs|
|Tricuspid valve||Located on the right side of the heart between the right atrium (RA)and right ventricle (RV)|
|Bicuspid valve||Located on the left side of the heart between the left atrium (LA) andthe left ventricle (LV)|
|Right ventricle||The chamber of the heart that pumps deoxygenated blood to thelungs|
|Left ventricle||Receives blood from the left atrium and pumps it into the aorta fortransport to the body cells|
|Septum||Divides the right and left chambers of the heart|
The heart is adapted to carry out its functions by having the following features:
The cardiac muscle is adapted to be highly resistant to fatigue.
The heart has a large number of mitochondria enabling continuous supply of energy to theheart and numerous myoglobins (oxygen storing pigment).
The presence of the cardiac muscles enables the heart to beat rhythmically.
The pericardium which surrounds and protects the heart from physical damage.
Pericardial fluid which prevents friction when the heart beats.
The outer layer of the pericardium attaches to the breastbone and other structures in the chestcavity and thus helps to hold the heart in place.
Bicuspid and tricuspid valves between atria and ventricles which prevent the backflow ofblood.
Septum which prevents the mixing of deoxygenated blood in the right and oxygenated bloodin the left chambers of the heart.
Its own blood supply for supplying nutrients and removing waste.
The left ventricle has thick muscular wall to pump blood at a higher pressure to the distantbody tissues,
The heart is supplied with the nerves which control the rate of heartbeat depending on thebody requirements.
Capillaries consist of anendothelium whichis only one cell thick.
Walls of arteries and veins consist of 3 layers.
The inner layer consists of a thin layer of endothelial cells.
The middle layer is made up of smooth muscle with some elastic fibres. This layer controls the diameter of the vessel and hence the amount of blood and its rate of flow.
The outer layer is composed of connective tissue; this holds the blood vessels in place in the body.
The walls of arteries are much thicker as it carries blood away from the heart at high pressure.
Major arteries close to the heart also have thick layers of smooth muscle in their walls to withstand the increases in pressure as the heart pumps.
The walls also have a large proportion of elastic fibres in both the inner and middle layers – this allows for the arteries to stretch according to the increases in volume of blood. As the heart relaxes the artery walls return to their original position, hence pushing the blood along – maintaining a constant flow in one direction.
Arteries are near the surface of the skin; the changes in the arteries diameter can be felt as a pulse.
The walls of veins are thinner than the walls of arteries, as the blood they receive from the capillaries is at a much lower pressure.
The walls have fewer elastic fibres and the lumen is wider (to allow for easier blood flow).
Veins have two mechanisms for keeping the blood flow constant and in one direction. Firstly, many veins are close to muscles, hence when the muscles contract they compress the walls of the vein – pumping blood forwards. Veins also havevalves which are spacedalong regular intervals in veins. They work much like one-way swinging doors – as the blood is forced through the valve opens. However, once the pressure drops and the blood flow decreases, the valve shuts – preventing backflow of blood.
They are extremely, tiny microscopic vessels that bring blood into close contact with the tissues, for the exchange of chemical substances between cells and the bloodstream.
The one cell thick endothelial layer is a continuation of the lumen arteries and veins.
Diffusion is a relatively slow process and hence the structure of capillaries is suited to slowing down the flow of blood.
In order to maximize the exchange of substances between the blood and cells, capillaries have thin walls (for more efficient diffusion) a small lumen (that forces blood cells to pass through in single file, slowing down the rate of flow and maximizing their exposed surface area).
They form an expansive blood flow network, such that no cells are far from blood supply
|Artery||Carries blood away from heart at high pressure||Thick, elastic, muscular walls to withstand pressure and to exert force (pulse)|
|Vein||Returns low-pressure blood to heart||Large diameter to offer least flow resistance. Valves to prevent back flow.|
|Capillary||Allows exchange of materials between blood and tissues||Thin, permeable walls|
|All arteries carry bloodawayfrom the heart||All veins carry bloodtowardsthe heart||Capillaries carry bloodfrom arteries to the veins|
|With the exception of the pulmonary artery, all arteries carryoxygenatedblood||With the exception of the pulmonary vein, all veins carrydeoxygenatedblood||Bloodslowly loses its oxygen|
|They carry blood which is usuallyrich in digested foodmaterials||Except for the hepatic portal vein, they carry blood which usuallyhaslittledigested foodmaterials||Bloodslowly loses its food|
|Have relatively narrower lumens (see diagrams above)||Have relatively wide lumens (see diagrams above)||Have relatively narrow lumens (see diagrams above)|
|Have relatively athicklayer of muscles and elastic fibres||Have relatively athinlayer of muscles and elastic fibres||Theydo not havemuscles and elastic fibres|
|They havethick outer walls||They havethin outer walls||Walls are onlyone cell thick|
|They carry blood athigh pressure||They carry blood atlow pressure||Pressure gradually fallsas blood flows from arteries to veins|
|Do not have valves (except for the semi-lunar valves of the pulmonary artery and the aorta)||Have valves throughout the main veins of the body to prevent the back flow of blood.||Have no valves|
|Have bright red blood (because it is rich in oxygen)||Brown-red blood||Brown-red blood|
|Located deep in the to body surface||Located near to body surface||Capillaries are found inside all tissues|
|Walls arenot permeable||Walls arenot permeable||Walls arepermeable|
|Blood flows in pulses||Nopulse||Pulse gradually disappears|
Plasma which is a clear extracellular fluid.
The solid component, which are made up of the blood cells and platelets
Erythrocytes, also known as red blood cells (RBCs)
Leukocytes, also known as white blood cells (WBCs)
Platelets, also known as thrombocytes
To pick up oxygen from the lungs and deliver it to tissues elsewhere.
To pick up carbon dioxide from other tissues and unload it in the lungs.
Phagocytes: Engulf and digest invading bacteria and viruses (pathogens). It is the body’smain defence against germs (microbes).
Lymphocytes: produce antibodies which neutralize antigens from bacteria or viruses. Theykill microbes or make them clump together, to be removed in the lymph glands.
Secrete vasoconstrictors which constrict blood vessels, causing vascular spasms in brokenblood vessels.
Form temporary platelet plugs to stop bleeding.
Secrete procoagulants (clotting factors) to promote blood clotting.
Dissolve blood clots when they are no longer needed.
Digest and destroy bacteria.
Secrete chemicals that attract neutrophils and monocytes to sites of inflammation.
Secrete growth factors to maintain the linings of blood vessels.
Plasma serves as a transport medium for delivering nutrients to the cells of the various organsof the body.
It transports waste products derived from cellular metabolism to the kidneys, liver, and lungsfor excretion.
It fights infections since it contains antibodies.
It is also a transport system for blood cells, and it plays a critical role in maintaining normalblood pressure.
Plasma helps to distribute heat throughout the body and to maintain homeostasis, orbiological stability, including acid-base balance in the blood and body.6. It carries and transports some hormones.
|AB||A and B||None||Anti-A and anti-B serums|
|O||None||Anti-A and anti-B||Neither serum|
Increase low haemoglobin levels: low haemoglobin can cause damage to body organs andtissues due to low oxygen levels. Donated blood, with sufficient haemoglobin, can correct theproblem of low haemoglobin level of the recipient.
Help stop bleeding: bleeding may not be controlled if platelets and/or clotting factors arelow. Receiving blood with high clotting factors can solve the problem.
Keeps the heart pumping: low blood volume can lead to low pressure and the heart may notbe able maintain the circulation of blood.
Help with serious blood infections when other methods fail. For example, blood transfusionmay serve as a treatment method for people with sickle cell anaemia or blood cancer(leukaemia).
Provide red cells and platelets when the bone marrow is compromised as with blood cancers,bone marrow transplants, chemotherapy, etc.
Provide red cells and platelets for patients with blood disorders such as sickle cell.
Save someone’s life: people who have had a big loss of blood due to a number of reasons canhave their lives saved once they receive donated blood.
Because blood transfusion involves screening of the donor’s blood, if the donor has anyhealth problem it can be detected and hence treated before getting worse.
Allergic reaction: This is the most common reaction. It happens during the transfusionwhen the body reacts to plasma proteins or other substances in the donated blood.
Fever reaction: The person gets a sudden fever during or within 24 hours of thetransfusion. Headache, nausea, chills, or a general feeling of discomfort may come withthe fever.
Haemolytic reactions: In very rare cases, the patient’s blood destroys the donor red bloodcells. This is called haemolysis. This can be severe and may result in bleeding and inkidney failure.
Donated blood must carefully and thoroughly be screened for any infectious diseasesbefore being transfused to the recipient. The blood should be screened for diseases likehepatitis B, HIV virus, and all sexually transmitted diseases (STDs).
The donated blood must be matched with the recipient’s blood type, as incompatibleblood types can cause a serious adverse reaction (transfusion reaction). Blood isintroduced slowly by gravity flow directly into the veins (intravenous infusion) so thatmedical personnel can observe the patient for signs of adverse reactions.
During blood transfusion, vital signs such as body temperature, heart rate, and bloodpressure are carefully monitored.
Some patients may get a sudden fever during or within 24 hours of the transfusion, whichmay be relieved with pain-relieving drugs such as panadol, diclofenac or paracetamol.This fever is a common reaction to the white blood cells present in donated blood.
Every cell in the body needs to received oxygen and nutrients. Blood rich in oxygen is sent tothe body organs, tissues and cells to nourish them through blood circulation.
It enables transportation of waste products from body tissues to excretory organs so as to beremoved from the body.
Protects the body against diseases and infections through the white blood cells.
Facilitates blood clotting to prevent loss of blood.
Maintains body temperature by distributing body heat evenly from the liver and spleen to allbody parts.
|Disease / Disorder||Description||Causes||Effects / Symptoms|
|1||Anaemia||A reduction inthe quantity of(oxygencarrying)haemoglobin inthe blood and/orbelow normalquantity of redblood cells.||The many possible causesinclude:1.Haemorrhagicanaemia – due to lossof blood2.Iron-deficiencyanaemia – due toinsufficient iron, oftendue tdietarydeficiency.3.Haemolytic anaemiaresult from theincreased destructionof red blood cells e.g.due to toxic chemicals,autoimmunity, theaction of parasites,abnormal forms ofhaemoglobin orabnormal red bloodcells.4.Anaemia can also becaused by the impairedproduction of red bloodcells, as in leukaemia(when red blood cellproduction in the bonemarrow is suppressed).||Main symptoms are:Excessivetiredness Breathlessnesson exertion Pallor (i.e.looking pale, esp.on face andpalms) Low resistance toinfe|
|2||Angina||Pain afterphysical effort||Narrowed coronary arteriesbeing unable to supplyincreased blood flow requiredfor increased physicalexertion. (The arteries mayhave been narrowed by theaccumulation of atheromatousplaque – see atherosclerosis,below.)||Typical symptomsinclude short-termdiscomfort such as anache, pain or tightnessacross the front of thechest when orimmediately followingexertion or othersituations in which heartrate is increased e.g. dueto panic or an argument.Other less commoneffects & symptoms arealso possible e.g. similarpain when or soon aftereating.|
|Aneurysm||Balloon-likebulge or swellingin the wall of anartery||In general, causes can begenetic or due to disease, e.g.1. a degenerative disease a syphilitic infection -causing damage to themuscular coat of theblood vessel2.a congenital deficiencyin the muscular wall||Aneurysms can causethe wall of the bloodvessel to weaken. Whenan aneurysm gets biggerthe risk of ruptureincreases. That can leadto severe haemorrhage(bleeding) and othercomplications – some ofwhich may be lifethreatening.|
|3||Arteriosclerosis||Hardening of thearteries.(Arteriolosclerosis is thehardening ofarterioles.)Artery wallsthicken, stiffenand loseelasticity, aprogressivecondition thattypicallyworsens overtime unlessaction is taken toaddress it.Note: Healthyarteries areflexible andelastic.||High blood pressure (alsoknown as hypertension) iswidely cited as a cause of, orat least a contributory factorto, the development ofarteriosclerosis.To reduce risk, keep bloodpressure within a healthyrange. See also how to reducerisk of atherosclerosis (below).||Arteriosclerosis (incombination withatherosclerosis orotherwise) can reducethe flow of blood,hence the supply ofoxygen, nutrients etc.,to tissues in theaffected area.Arteriosclerosis canaffect any artery in thebody but is of greatestconcern when occurs inthe heart (coronaryarteries) or the brain.|
|4||Atherosclerosis (Atheroma)- a commontype ofarteriosclerosis (see above)||•Multiple fatty plaques(consisting of e.g.cholesterol andtriglyceride)accumulate on theinner walls of arteries.To reduce risk:1. Eat sensibly (seebalanced diet)2.Don’t smoke3. Take appropriateregular exercise4. Maintain a healthybody weight5. Do not consumeexcessive alcohol||A chronic disease thatcan remainasymptomatic fordecades. However,blood flow is restrictedand eventuallyobstructed.Various complicationsof advancedatherosclerosis arepossible. One of themost significant risks isof an infarction due tosoft plaque suddenlyrupturing, causing theformation of a thrombus(blood clot) that canslow or stop blood flowleadingto death of thetissues fed by the artery.Thrombosis of acoronary artery cancause a heart attack(Myocardial infarction).The same process in anartery to the brain iscommonly calledstroke.6. CoronarythrombosisA thrombus is ablood clot.Thrombosis is acondition inwhich bloodchanges from aliquid into aCoronary thrombosis canoccur due to the accumulationof fatty deposits (plaques)inside the arteries, i.e.atherosclerosis. The hardeningof arteries (arteriosclerosis)can also contribute to reducedCan lead to a|
|6.||Coronarythrombosis||A thrombus is ablood clot.Thrombosis is acondition inwhich bloodchanges from aliquid into asolid state,producing a ‘clot'(thrombus).Coronarythrombosis isthe condition inwhich thethrombus isformed in one ofthe 3 majorcoronary arteriesthat supply theheart.||Coronary thrombosis canoccur due to the accumulationof fatty deposits (plaques)inside the arteries, i.e.atherosclerosis. The hardeningof arteries (arteriosclerosis)can also contribute to reducedblood flow leading to coronarythrombosis.||Can lead to amyocardial infarction(heart attack).Sensations that might beindications of coronarythrombosis leading tomyocardial infarctioninclude: sudden sharppain behind thesternum (breastbone) sudden sharppain on the lefthandside of thechest, that mightspread down theleft arm pain radiatingtowards the jaw,ear, handsstomach, rightarm constrictingsensation in thethroat areadifficultybreathing sudden, severedizziness and/orfainting,experienced withpain.|
|7.||Haemophilia||Blood clots onlyvery slowly.||Deficiency of either oftwo blood coagulationfactors:o Factor VIII(antihaemophilic factor), oro Factor IX(Christmasfactor) Hereditary -symptoms in males;may be ‘carried’ byfemales who can pass itto their sons withoutbeing affectedthemselves.||The person mightexperience prolongedbleeding after any injurythat causes an openwound. In severe casesof haemophilia theremay be spontaneousbleeding into musclesand joints.Treatment: Bleeding incases of haemophilia hasbeen treated bytransfusions of plasmacontaining the missingfactor, or withconcentratedpreparations of FactorVIII or Factor IXobtained by freezingfresh plasma.|
|8||Haematoma||A collection oraccumulation ofblood outside theblood vessels,which may clotforming aswelling.||The different types ofhaematoma generally havedifferent causes: An intracerebralhaematoma may bedue to a head injury. A perinealhaematoma may occurdue to bleeding from avaginal tear orepisiotomy (cut) duringchildbirth.||Effects & symptomsalso depend on the typeof haematoma: An intracranialhaematomamight compressthe brain andincrease pressurewithin the skull A subduralhaematoma canbe lifethreatening|
|9.Haemorrhoids||Haemorrhoids(also called’piles’) areswellingscontainingenlarged andswollen bloodvessels in oraround therectum and anus.||Risk factors – rather than directcauses – include: excessive body weight prolonged constipatione.g. due to insufficientdietary fibre. prolonged diarrhoea lifting heavy objectsfrequently pregnancy – which canplace increasedpressure on pelvicblood vessels, thoughhaemorrhoids oftendisappear after thebirth age (above 50 years) family history ofhaemorrhoids (geneticpredisposition)||Symptoms ofhaemorrhoids caninclude: Bleeding (brightred blood) afterpassing a stool A pile movingdown, outside ofthe anus(prolapse) a mucusdischarge afterpassing a stool itchiness aroundthe anus soreness andinflammationaround the anussensation ofbowels still beingfull and in needof emptying|
Removes excess fluid and waste products from the interstitial spaces between the cells andreturns it into the bloodstream.
It also functions in transporting white blood cells to and from the lymph nodes into thebones, and antigen-presenting cells (APCs), such as dendritic cells, to the lymph nodes wherean immune response is stimulated.
Special lymph vessels (lacteals) absorb fat and fat-soluble vitamins from the small intestineand deliver these nutrients to the cells of the body where they are used by the cells.
Protects the body against germs. Lymph glands produce lymphocytes which produceantibodies that fight against microbes. They also contain phagocytes, which eat dead whitecells and microbes in the lymph.
Filarial infection can cause lymphoedema of the limbs, genital disease (hydrocele, chylocele,and swelling of the scrotum and penis). It also causes recurrent acute attacks, which areextremely painful and are accompanied by fever.
The infected people may have lymphatic and kidney damages.
Sometimes the swollen limbs become infected.
The infected person is disabled and cannot work to earn his/her living.
spraying insecticides to kill mosquitoes;
giving antibiotics to prevent or control infection;
giving medications to kill microfilariae circulating in the blood;
applying pressure bandages to reduce swelling; and
surgically removing infected tissue.
Provides support for woody plants.
Transports water and solutes from roots to all plant parts.
A large amount of absorbed water is lost during transpiration which is harmful to plants.
Unnecessary wastage of energy takes place during the process of water absorption which islost due to transpiration.
When the rate of transpiration is high in plants growing in soil deficient in water, an internalwater deficit develops in plants which may affect metabolic process.
Many xerophytes undergo structural modifications and adaptations to check transpiration.
Transpiration is high at low atmospheric pressure and it is low at high atmospheric pressure.Plants that grow naturally at higher altitudes, where the atmospheric pressure is low, havemodified leaves to reduce the rate of transpiration.