2 Topic Outline Digestion The Transport System Pathogens and Disease Defense AgainstInfectious DiseaseGas ExchangeHomeostasis &ExcretionReproductionHOME
3 5.1.1 Explain why digestion of large Topic Digestion5.1.1 Explain why digestion of largefood molecules is essential.Digestion is necessary because it breakslarge food molecules into smaller moleculesthat can be absorbed into the villi of thesmall intestine and eventually travel throughthe blood. Simple molecules can thendissolve in blood and go into circulation toreach every part of the body.MAIN PAGE
4 Enzymes are needed for digestion because 5.1.2 Explain the need forenzymes in digestion.Enzymes are needed for digestion becausethey increase the rate at which food moleculesare broken down into their simplest form.Without enzymes, the reactions neededfor digestion would take a reallyreally long time.
5 5.1.3 State the source, substrate, products and optimum pH conditions for oneamylase, one protease and one lipase.One amylase: source is salivary glands in themouth; substrate is starch; productis maltose; and optimum pH isabout 7 (balanced).
6 One protease (a.k.a. pepsin): source is glands in stomach wall; substrate is proteins;product is polypeptides; optimum pH is 2 (acidic).One lipase: source is the pancreas; substrateis lipids; product is glycerol and fattyacids; optimum pH is basic(higher than 7).
7 Drawing will be inserted at a later date. 5.1.4 Draw a diagram of thedigestive system.Drawing will be inserted at a later date.
8 5.1.5 Outline the functions of the stomach, small intestine, and large intestine.The stomach is where the protein digestion processbegins. Pepsin breaks the proteins down into smallpolypeptides. The small intestine is the site wheremost of the breaking down of food occurs,and also where absorbtion of nutrients occurs.
9 This is where fats being to be broken down. Starch, glycogen, and smaller polysaccharidesare hydolyzed into disaccharides such asmaltose. Maltose in the split into twosimpler molecules of maltase.
10 The lining of the small instestine is made of small villi, little finger-like membrane foldsthat absorb small molecules, putting them in thecirculatory system (sugars & peptides) orthe lymphatic system(fats).
11 In the large intestine, or colon, water is reabsorbed and the wastes of the digestivetract, feces, are taken up. They becomemore solid by the removal of water,and then go out of the rectum.
12 absorption and assimilation. 5.1.6 Distinguish betweenabsorption and assimilation.Absorption is the passage of digested substancesthrough the wall of the intestine intothe blood capillaries in bodies. Assimilationis a process by which food becomesincorporated with the body withoutbeing broken down.
13 5.1.7 Explain how the structure of the villus is related to its role in absorption of the end products of digestion.A villi is a folded finger-like structure. They increase the surface area for absorption. They contain a network of blood capillaries and a lymph vessels so that the absorbed materials can circulate throughout the body. They are located in the small intestine.
14 Topic 5.2 - The Transport System 5.2.1 Draw a diagram of the heart showing all four chambers, associate blood vessels and valves.The diagram will be inserted at a later dateMAIN PAGE
15 5.2.2 Describe the action of the heart in terms of collecting blood, pumping bloodand opening and closing valves.The blood is collected by the atria, and isthen pumped out by the ventricles intothe arteries. The direction of flow iscontrolled by atrio-ventricular andsemilunar valves.
16 5.2.3 Outline the control of the heartbeat in terms of the pacemaker, nerves and adrenalin.The wall of the right atrium is made of a specializedtissue forming a structure called the sinoatrialnode (SAN) also known as the pacemaker.It spontaneously produces electrical impulseswhich spread to the two atria causingthem tocontract.
17 The brain controls the heart rate and the pacemaker receives two nerves from thebrain stem. One of these nerves, thesympathetic nerve, releases noradrenaline,and causes the heart rate to increases.
18 The parasympathetic nerve releases acetylcholine and lowersthe heart rate. The hormoneadrenaline is released by the adrenal glandand prepares the body to situationsof stress by increasing the heart rateand also blood sugar levels.
19 5.2.4 Explain the relationship between the structure and function of arteries,capillaries and veins.Arteries carry blood that's pumped out bythe thick walls of the ventricles. Theyhave thick walls because this is whenthe blood has the highest pressure.These walls are made of connectivetissue, elastic and muscle fibers anda layer of endothelial cells.
20 The elastic tissue allows the arteries to expand and recoil. This helps push the blood in thecirculation. Veins have thinner walls. Theycarry blood from the body back to the heart.They have thinner layers of connective,elastic and smooth muscle fibers.
21 Cappilaries only have one layer of endothelium as their walls. This allows substances to pass inand out of capillaries for exchange of materials.They have a very narrow diameter,but there aremany cappilaries allowing a largeexchange of materials
22 5.2.5 State that blood is compose of plasma, erythrocytes, leucocytes (phagocytesand lymphocytes) and platelets.Blood is composed of plasma,
23 5.2.6 State that the following are transported by the blood: nutrients, oxygen, carbondioxide, hormones, antibodies and urea.Nutrients, oxygen, carbon dioxide,hormones, antibodies and ureaare transported by blood.
24 Topic 5.3 - Pathogens and Disease 5.3.1 Define pathogen.Pathogen - an organism or virus that causes a disease.MAIN PAGE
25 5.3.2 State one example of a disease caused by members of each of the followinggroups: viruses, bacteria, fungi,protozoa, flatworms and roundworms.Viruses:Influenza.Bacteria: Cholera.Fungi: Athlete's foot.Protozoa: Malaria. Roundworms:
26 Roundworms: Ascaris eggs contained in contaminated food are swallowed, circulate through the blood stream,reach the lungs, grow into larvaein the nasal cavities, swallowed intothe stomach where they grow intoadult worms and start the cycle again.Flatworms: Pork tapeworm.
27 5.3.3 List six methods by which pathogens are transmitted and gain entry to the body.From the air,2) Direct contact,3) Through food,4) Cuts in the skin,5) Blood transfusion,6) Animals and insects.
28 5.3.4 Describe the cause, transmission and effects of one human bacterial disease.Diptheria is a bacterial disease the is breathedin and infects the nose, throat, and larynx.The bacteria releases toxins that destroytissues in the heart nerves and glands.
29 5.3.5 Explain why antibiotics are effective against bacteria but not viruses.Antibiotics block specific metabolic pathwaysfound in bacteria, but not in eukaryotic cells.Viruses reproduce using the host cellmetabolic pathways that arenot affected by antibiotics.
30 5.3.6 Explain the cause, transmission and social implications of AIDS.AIDS is a retrovirus having RNA as its geneticmaterial and not DNA. It transcribes itsRNA into DNA using an enzyme calledreverse transcriptase. IDS is a syndromewhere the immun system fails andopportunistic pathogens cause further harm.
31 It is transmitted by sexual intercourse, sharing of needles, blood transfusions,accidents causing blood contamination,cuts in the skin, tattoos and earpiercing with infected needles.
32 Social implications are that people don't feel very comfortable with a person who has AIDS.People with AIDS can find it difficult to buyhealth insurance plans, find jobs, have friends,and build normal social relations. People havechanged their sexual life styles due toawareness and education about AIDS.
33 Topic 5.4 - Defense Against Infectious Disease 5.4.1 Explain how skin and mucous membranes act as barriers against pathogens.The skin and mucous membranes are the first lines of defense against disease. The skin has a thick keratin layer on the surface which doesn't allow any organisms to enter the body.MAIN PAGE
34 Where there is no skin, such as the mouth cavity, epithelial cells there form a mucousmembrane that produces mucous which trapsand stops the action of many pathogens
35 5.4.2 Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissues.When the phagocytes meet the pathogens, theyingest the organisms by phagocytosis (eating).Once they are in the phagocytes, the pathogensgo into the vesicles which fuse with the lysosomes,which then release hydrolytic enzymeson them and destroy them.
36 5.4.3 State the difference between anitgens and antibodies.An antigen is a foreign macromolecule thatdoes not belong to the host organism andthat elicits an immune resonse. An antibodyis a protein and is called an immunoglobulin.It is made of 4 polypeptides, 2 heavy chainsand 2 light chains. It sticks toantigens and to lymphocytes.
37 5.4.4 Explain antibody production. Many different types of lympocytes exist.Each type recognizes one specific antigenand responds by dividing to form a clone.This clone then secretes a specificantibody agaist the antigen.
38 5.4.5 Outline the effects of HIV on the immune system.HIV attacks helper T cells, which are partof the immune system that are importantfor the function of B lymphocytes.The virus enters the helper Tcells and replicates there.
39 The cells burst and release new viruses, these viruses infect other helper T cells and possiblyother cells such as phagocytes as well. Thedestruction of helper T cells paralyses theimmune system since they communicatebetween different cells of the immunesystem and activate them.
40 This enables any other parasite or organism usually kept under control by the immune system tobe able to affect the body. What makes thisdisease more serious than others is thatHIV replicates in a immune system cell.Therefore, by creating more of itself itis also killingthe cells that could kill it.
41 5.5.1 List the features of alveoli that adapt them to gas exchange. Topic Gas Exchange5.5.1 List the features of alveoli that adapt them to gas exchange.There is a large surface area, a dense network of capillaries.a wall consisting of a single layer of flattened epithelial cells separated from one another by a thin basement membrane,MAIN PAGE
42 allowing for easy diffusion of substances across this wall (so that the barrier between theair in an aveolus and the blood in its capillariesand gases are exchanged between the airand blood by diffusion), and a thin membrane,the pleura, lines the thoracic cavity secretea fluid to lubricate and keep aveoli moist.
43 5.5.2 State the difference between ventilation, gas exchange, and cell respiration.Ventilation is a method of increasing contactbetween the respiratory medium and therespiratory surface. It maintains a highconcentration of oxygen in thealveoli and low carbon dioxideas we breathe in and out.
44 Gas exchange occurs between the aveoli and the capillaries by diffusion, oxygen passesfrom the alveoli to the capillaries and carbondioxide passes from the capillaries to thealveoli.Cell respiration is the chemical reactionthat occurs inside the cell and that results in thecontrolled production of energy in the form of ATP.
45 5.5.3 Explain the necessity for a ventilation system.A ventilation or gas-transport, system is neededin order to obtain oxygen for the organism(which takes part in the oxidation of organiccompoundsthat serve as cellular energy sources)and to get rid of carbon dioxide that isproduced as a by-product.
46 A true ventilation system is needed for larger animals when diffusion of oxygen throughcells is not enough to supply all the oxygenneeded in the organism. It is neededto maintain concentration gradientsin the alveoli.
47 5.5.4 Draw a diagram of the ventilation system including trachea, bronchi,bronchioles, and lungs.This will be answered at a later date
48 5.5.5 Explain the mechanism of ventilation in human lungs including the action ofthe internal and external intercoastalmuscles, the diaphragm andthe abdominal muscles.To inhale, the diaphragm contracts andflattens and the external intercoastalmuscles also contract and cause theribcage to expand and move up.
49 The diaphragm contracts drops downwards. Thoracic volume increases, lungs expand, and the pressureinside the lungs decreases, so that air flows into thelungs in response to the pressure gradient. Thesemovements cause the chest cavity to become largerand the pressure to be smaller, so air rushes in fromthe atmosphere to the lungs.
50 To exhale, the diaphragm relaxes and moves up. In quiet breathing, the external intercoastalmuscles relax causing the elasticity of the lungtissue to recoil. In forced breathing, the internalintercostals muscles and abdominal muscles alsocontract to increase the force of the expiration.
51 Thoracic volume decreases and the pressure inside the lungs increases. Air flowspassively out of the lungs in response tothe pressure gradient. The ribs to movedownward and backward causing the chestcavity to become smaller in volume and thepressure increases pushing air out ofthe lungs into the atmosphere.
52 Topic 5.6 – Homeostasis and Excretion 5.6.1 State that homeostasis involves maintaining the internal environment at a constant level or between narrow limits, including blood pH, oxygen and carbon dioxide concentrations, blood glucose, body temperature and water balance.MAIN PAGE
53 Homeostasis involves maintaining the internal environment at a constant level or betweennarrow limits, including blood pH, oxygen andcarbon dioxide concentrations, blood glucose,body temperature and water balance
54 5.6.2 Explain that homeostasis involves monitoring levels of variables andcorrecting changes in levels bynegative feedback mechanisms.If body temperature falls below 37 degreesCelsius, then messages are sent by thehypothalamus to different parts ofthe body so temperatureis increased to normal.
55 Conversely, if body tempature rises above 37 degrees Celsius, messages sent decreasebody temperature to normal. Therefore,a change in a variable is counteracted bythe opposite change to return thebody to a normal temperature.
56 5.6.3 State that the nervous and the endocrine systems are both involved in homeostasis.The nervous and endocrine systemsare both involved in homeostasis
57 5.6.4 State that the nervous system consists of the central nervous system(CNS) andperipheral nerves and iscomposed of special cells called neuronsthat can carry electrical impulses rapidly.The nervous system consists of thecentral nervous system (CNS) andperipheral nerves and is composed ofspecial cells called neurons that cancarry electrical impulses rapidly.
58 5.6.5 Describe the control of body temperature including the transfer of heat in blood,the role of sweat glands and skinarterioles, and shivering.First, the nerve cells beneath the skin,thermoreceptors, detect a change in theenvironment surrounding the human.These thermoreceptors send messagesthat are received by the hypothalamus.
59 The hypothalamus is made of nerve cells and is considered a part of the nervous and endocrinesystems. Hormones are released from thehypothalamus and they travel to the pituitarygland. The pituitary gland then releases ahormone bound for the thyroid-gland whichin turn releases thyroxin.
60 The release of thyroxine increases the metabolic rate of the body and in turn releases moreheat. For example, when the weatheris hot, less thyroxine is released and lessheat is produced. The hypothalamus alsoplays a role in transmitting nerve messagesto muscles, blood capillaries and sweat glands.The effect of this is the occurrence of responsessuch as shivering, vasoconstrictionor vasodilatation and sweating.
61 5.6.6 State that the endocrine system consists of glands which release hormonesthat are transported in the blood.The endocrine system consists ofglands which release hormones
62 5.6.7 Explain the control of blood glucose concentration, including the roles ofglucagon, insulin, and alpha andbeta cells in the pancreatic islets.Insulin and glucagon regulate thesugar level in the body. These twohormones are manufactured in thepancreas and through circulationare carried to the liver where theyperform their functions.
63 Enzymes that convert glucose to glycogen though a condensation reaction are stimulatedby Insulin. Enzymes that hydrolyze glycogento glucose are stimulated by glucagon.Receptors in the pancreas are sensitive tothe changes in sugar level, thus releasingthe necessary requirements of insulin andglucagon depending on the needs of thebody. The beta cells found in the islets ofthe pancreas make insulin and the alphacells make glucagons.
64 Excretion is the removal of metabolic waste from the body. 5.6.8 Define excretionExcretion is the removal ofmetabolic waste from the body.
65 5.6.9 Outline the role of the kidney in excretion and the maintenance of water balance.The human body contains two kidneys locatedat the back of the abdominal cavity.A tube called the ureter connects eachkidney and runs downward to empty in asac-like structure called the urinary bladder.
66 The renal artery supplies each kidney with urea or other unwanted material and alsooxygen. The renal vein leaves the kidneyswith blood that contains the correct amountsof urea, salts and water. Carbon dioxide isprevalent in the renal vein and this isreleased by the kidney as respiratory waste.
67 The urinary bladder opens up to two things: the urethra which empties urine to theoutside of the body and the sphinctermuscles which guard the emptying ofurine and provide that urination can becontrolled under normal circumstances.
68 5.7.1 Draw diagrams of the adult male and female reproductive systems. Topic Reproduction5.7.1 Draw diagrams of the adult male and female reproductive systems.Diagrams will be inserted at a later date.MAIN PAGE
69 5.7.2 Explain the role of hormones in regulating the changes of puberty(testosterone, estrogen) in boys andgirls, and in the menstrual cycle(follicle stimulation hormone (FSH),luteinizing hormone (LH), estrogen,and progesterone).From birth to the age of ten, testosteronelevel is very low. It increases sharply afterthat and begins puberty in males.
70 This is when sperm production takes place. Testosterone stays at high levels until the ageof 40-50, then it gradually decreases. It isalso responsible for voice change, hair growthin certain parts of the body, and the buildingof muscles. Estrogen leads to the productionof eggs, which leads to the menstrual cycle.In the menstrual cycle, FSH is secreted bypituitary increases, this is responsible forthe growth of an oocyte (an immatureegg) and it's follicle.
71 Two weeks after the start of menstruation, ovulation occurs due to a sudden and sharpincrease in LH from the pituitary gland. It alsocauses the empty follicle to develop into theyellow body which starts releasing the hormoneprogesterone. This is responsible for maintainingand thickening the endometrium (wall of theuterus) in preperation for implantation.
72 5.7.3 List the secondary sexual characteristics in both sexes.Secondary sexual characteristics in males are thegrowth of hair in certain parts of the body,change in voice, and building of muscles.In females, it is the growth of hair incertain places and the beginningof the menstrual cycle.
73 5.7.4 State the difference between copulation and fertilization.Copulation is the physical contact between themale and female reproductive structures thatis needed for the sperms to move fromthe male to the female but does notnecessarily result in fertilaztion due to theuse of a contraceptive or being infertile.Fertilization is the fusion of the male andfemale nuclei to produce the zygote.
74 5.7.5 Describe early embryo development up to the implantation of the blastocyst.Fertilization occurs and results in the formationof the zygote which starts a series ofcell divisions. (dividing process=cleavage).
75 Cleavage continues, with the embryo becoming a ball of cells by the time is reaches the uterusabout 3 to 4 days after fertilization. by about1 week after fertilization, cleavage has porucedan embryonic stage called the blastocyst.During the next 5 days, the blastocystimplants into the endometrium.
76 5.7.6 State that the fetus is supported and protected by the amniotic sacand amniotic fluid.The fetus is supported and protectedby the amniotic sac and amniotic fluid.
77 5.7.7 State that materials are exchanged between the maternal and fetal blood in the placenta.Materials are exchanged betweenthe maternal and fetal blood in the placenta.
78 5.7.8 Outline the process of birth and its hormonal control, including progesterone and oxytocin.Labor, delivery and afterbirth mark the three stagesof birth. Labor is marked by contractions ofthe uterus, it is stimulated by a hormonecalled oxytocin, which is released bythe pituitary gland.
79 Dilation of the cervix also occurs at this time. Later, the cervix becomes fully dilated. Themost powerful contractions are during thenext stage, delivery. Placenta, along withother fluids and blood come out after thebaby. This placenta that comes out marksthe afterbirth. Labor and delivery arecontrolled by the actions of oxytocin,progeterone, and oestrogen
80 5.7.9 Describe four methods of family planning and contraception.There is sterilization. In this, the female gets a tubeLegation where the oviducts are tied so the spermcan't reach the egg, or the male gets avasectomy where the sperm ducts arecut and prevents the release of sperm.
81 Another method is pills. These prevent ovulation by inhibiting FSH and LH. The use of a malecondom prevents the release of sperm intovagina. Another method is intrauterine device(IUD) which prevents fertilization or implantation.A behavioral form of contraception isto, of course, not have sex.
82 5.7.10 Discuss the ethical issues of family planning and contraception.Some people beleive it is unethical to abort a baby,that is to kill a fetus that was formed after fertilization.Other people think it is the right of the womancarrying the fetus to decide what to do with it.Some people, such as Mormons, believe that itis right to produce as many children as possible.Thus, for them any type of familyplanning is unethical.
83 5.7.11 Outline the technique of amniocentesis. Amniocentesis is where some amniotic fluid is drawnby a syringe through the abdomen of the mother.The cells are then grown on a tissue culture to bestudied to create a karyotype and are thenstudied to find out if the are any abnormalties.
84 5.7.12 Outline the process of in vitro fertilization (IVF).Eggs are removed from the ovaries of a womanby suction through the vagina. They are suckedinto a syringe and placed in a glass dish.
85 The eggs are then cleaned to remove blood and other unwanted material. The egg isthen incubated. Then, sperms are addedand fertilization takes places and theembryo is then transferred throughthe vagina to the uterus.
86 5.7.13 Discuss the ethical issues of IVF. This is, of course, an artificial process. If onebeleives that those who cannot have childrenare meant not to have children, one wouldnot support IVF. In addition, IVF oftenincludes the fertilization of many eggsin order to insure that one willproduce a healthy baby.
87 The other zygotes, however, are often thrown away, which is a form of abortion.If one believes abortion is wrong, thenone would have to deliver all the babiesthat are produced via a test tube. Thisis why mothers who do IVF oftenhave many children in one delivery.MAIN PAGE