1. Topic 6: Human Health and Physiology
Digestion

2. Explain why digestion of large food molecules is essential.
The foods that we eat are not necessarily usable in their current form by our tissues. They have to be broken down and changed into another form.
Food molecules are simply too large to be absorbed by the villi in the small intenstine, once again they have to be broken down into small forms.

3. Explain the need for enzymes in digestion.
Without enzymes digestion would still occur, however at a significantly slower pace.

4. Enzyme: Salivary Amylase | Pepsin | Pancreatic lipase
State the sources, substrate, products and optimum pH conditions for one amylase, one protease, and one lipase.
Enzyme: Salivary Amylase | Pepsin | Pancreatic lipase
Source: Salivary glands | Wall of Stomach | Pancreas
Substrate: Starch | Proteins | Triglycerides (fats or oils)
Products: Maltose | Small polypeptides | Fatty Acids and Glycerol
Optimum pH: pH 7 | pH | pH 7

5. Draw a diagram of the digestive system.
Mouth
Esophagus
Stomach
Small & large Intestines
Anus
Liver
Pancreas
Gall bladder
Interconnections between structures

6. Outline the function of the stomach, small intestine and large intestine.
Digestion of proteins begins in the stomach, where the process is catalyzed by the enzyme pepsin where possible harmful bacteria are killed by the stomach's acidic condition which is also the optimum conditions (pH 1.5-2) for the enzyme pepsin.
In the small intestine, enzymes complete the process where the end matter is absorbed by villi.
The large intestine absorbs water and passes the unabsorbable rest off as feces.

7. Distinguish between absorption and assimilation.
Absorption is when food molecules pass through a layer of cells such as passing through the villi.
Assimilation is when food actually becomes part of the body's tissue.

8. It increases the surface area of the small intestine
Explain how the structure of the villus is related to its role in absorption of the end products of digestion.
It increases the surface area of the small intestine
The epithelium has a surface of only a thin layer of cells.
Protein channels in the microvilli allow for quick absorption of foods via facilitated diffusion and active transport.
Blood capillaries close to epithelium making it only a small distance for diffusion to occur.

9. Topic 6: Human Health and Physiology
The Transport System

10. Draw a diagram of the heart showing all four chambers, associated blood vessels and valves, and the route of blood through the heart.

11. The Coronary Arteries supply heart muscle with oxygen and nutrients.
State that the Coronary Arteries supply heart muscle with oxygen and nutrients.
The Coronary Arteries supply heart muscle with oxygen and nutrients.

12. Describe the action of the heart in terms of collecting blood, pumping blood and opening and closing valves.
The right atrium relaxes for the blood to be received from the superior and inferior vena cava.
The atrioventricular valve opens for blood to go to the right ventricle by the contracting atrium.
The right ventricle then relaxes to receive the blood from the atrium. Then it contracts in order to open up the pulmonary valves. Deoxygenated blood goes through to the pulmonary artery, where it enters the lungs so that the blood will be oxygenated.
Blood returns from the lungs to the heart through the pulmonary veins, now oxygenated.
The left atrium relaxes to receive it and then contracts to pump blood and open the atrioventricular valve where then the blood goes to the relaxed left ventricle.
The left ventricle contracts to open the semilunar valves and then the blood goes through the aorta to the rest of the body.

13. Describe the action of the heart in terms of collecting blood, pumping blood and opening and closing valves.

14. Outline the control of the heartbeat in terms of myogenic muscle contraction, role of the pacemaker, nerves, the medulla of the brain and epinefrine (adrenalin).
The heart muscle may have an intrinsic contractile property that is independent of the nervous system
The pacemaker is located in the wall of the right atrium at the Sinoatrial node (SAN).
Each time the pacemaker sends out a signal, the heart carries out a contraction or a beat.
The heart beats by itself (myogenic).
Nerves and hormones can transmit messages to the pacemaker:
Sympathetic nerve secretes adrenaline (also known as "epinephrine") which carries messages from the brain to the pacemaker telling the pacemaker to speed up the beating of the heart.
Another nerve tells it to slow it down, and Adrenalin, carried to the pacemaker by the bloodstream tells it to speed up the beating of the heart.

15. Explain the relationship between the structure and function of arteries, capillaries, and veins.
Thick wall to withstand high blood pressure.
Thick outer layer of longitudinal collagen and elastic fibers.
Thick layers of circular elastic and muscle fibers.
walls stretch and recoil for the blood to go from the heart to the small intestine.
Narrow lumen to help maintain the high pressure.
Capillaries:
Has pores to allow plasma and phagocytes to diffuse in or out.
Connects the vein and artery
Moist and thin for diffusion and has a short diffusion distance.
Narrow diameter and large quantity allow for a large exchange of materials through diffusion
Veins
Thin layers with a few circular elastic and muscle fibers.
Thin walls to allow the muscles to squeeze the veins
Thin outer layer of longitudinal collagen and elastic fibers.
Valves for blood to stay and not flow backwards.
Wide lumen to accommodate for the slow flowing of blood

16. Blood is composed of plasma, erythrocytes, leukocytes and platelets.
State that blood is composed of plasma, erythrocytes, leukocytes, (Phagocytes and lymphocytes) and platelets.
Blood is composed of plasma, erythrocytes, leukocytes and platelets.

17. State that blood is composed of plasma, erythrocytes, leukocytes, (Phagocytes and lymphocytes) and platelets.

18. The following are transported in the blood:
State that the following are transported by the blood; nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat.
The following are transported in the blood:
Nutrients
Oxygen
Carbon dioxide
Hormones
Antibodies
Urea
Heat.

19. Topic 6: Human Health and Physiology
Defense against infectious disease

20. Define pathogen
Pathogen: an organism or a virus that causes a disease.

21. Explain why antibiotics are effective against bacteria but not viruses.
Antibiotics are drugs which kill or slow the growth of bacteria.
Antibiotics block metabolic pathways of bacteria, inhibiting cell wall formation and protein synthesis, resulting in the death of foreign bacteria.
However, viruses are not alive and utilize the organisms host cells to replicate, which are not targeted by antibiotics.
In order to kill a virus by antiobiotics human cell has to be killed as well

22. Explain how skin and mucous membranes act as barriers against pathogens.
The skin and mucous membranes form a barrier that prevents most pathogens from entering the body.
The other layers of the skin are tough and form a physical barrier.
These dry, keratinised layers of skin discourage pathogen growth.
The skin also produces a thin layer of acid and oils.
Mucus contain an enzyme called lysozyme which kills bacteria.

23. Outline how phagocytic leukocytes ingest pathogens in the blood and in body tissue.
Phagocytes are a type of leukocytes which ingest and destroy foreign matter through phagocytosis.
They can easily move through the walls of blood capillaries and the site in which there is an infection.
A phagocyte comes in contact with pathogen cells and does not recognize the glycoprotein structure on its cell wall.
The pathogen is then ingested through endocytosis. Plasma membrane forms around pathogen.
Pathogen vacuole then binds with lysosome containing digestive enzymes which break down the pathogen.
Large numbers of phagocytes form pus.

24. State the difference between antigens and antibodies.
Antigens are macromolecules that elicit an immune response by lymphocytes.
Antibodies are proteins secreted by plasma cells that bind to a particular antigen and mark it for elimination.

25. Explain antibody production.
Antibodies are made by lymphocytes, which recognize an enormous number of antigens, but each individual cell recognizes only one type of antigen.
Each lymphocyte puts some of the antibody that it makes into its cell surface with the antigen-combining site projecting outwards.
When a pathogen enters the body, its antigens bind to the antibodies in the cell surface of one type of lymphocyte.
The selected lymphocyte proliferates to give rise to a clone of identical cells bearing receptors for the selecting antigen.
Some of the cells develop into short-lived plasma cells that secrete antibody specific for the antigen.
Others develop into long-lived memory cells that can respond rapidly upon subsequent exposure to the same antigen.

26. Outline the effects of HIV on the immune system.
HIV attacks T-cells which are part of the immune system that are important for the formation of Beta lymphocytes.
The virus enters the T-Cells and replicates there.
As reproduction increases, the cell breaks up and the virus RNA is spread to other T-cells.
The virus keeps infecting and killing other T-cells, paralyzing the immune system.
This enables other organisms usually kept under control by the immune system to be able to affect the body.

27. Explain the cause, transmission, and social implications of AIDS.
AIDS or Acquired Immunodeficiency Syndrome is a collection of symptoms and infections caused by infection with the human immunodeficiency virus (HIV).
Transmission:
HIV is transmitted via direct contact of the mucous membrane with a bodily fluid containing HIV such as blood, semen, or breast milk.
The transmission could be through anal or penetrative sex, blood transfusion, contaminated needles, or during pregnancy.
Most researches think that the virus originated from the Sub-Sahara, but the exact cause is unknown.
Social Implications Fear and apprehension for those associated with the disease, the lifestyle associated with the disease is attacked, trouble getting a job or even getting health insurance- distanced from society

28. Topic 6: Human Health and Physiology
Gas Exchange

29. State the difference between ventilation, gas exchange and cell respiration.
Ventilation: Is the process of inhaling and exhaling, with oxygen entering the alveoli (large surface area).
Gas exchange: Process of exchanging one gas for the other between alveoli and capillaries. (Carbon dioxide for oxygen).
Cell Respiration: The chemical process occurring in the mitochondria where energy is released as ATP.

30. Explain the necessity for a ventilation system.
A ventilation system is needed in order to obtain oxygen for living organisms and to get rid of carbon dioxide.
Surface diffusion utilized by many smaller organisms is not sufficient in supplying the oxygen needs of the body.
It is also needed to maintain a concentration gradient in the alveoli.

31. List the features of the alveoli that adapt them to gas exchange.
Cells secrete fluid making the inner surface moist.
Increase in surface area.
Single layer of cells allowing for short diffusion distance
Dense network of capillaries near the surface.

32. Draw a diagram of the ventilation system including trachea, bronchi, bronchioles, and lungs.
Alveoli

33. Explain the mechanism of ventilation in human lungs, including the action of the internal and external intercostals muscles, the diaphragm, and the abdominal muscles.
When we inhale, the diaphragm moves down and becomes flat because abdominal muscles relax(allowing for more air).
The volume of the thorax increases, air flows into the lungs.
External intercostal muscles contract.
When we exhale, abdominal muscles contract and the diaphragm becomes dome-shaped, moving up.
The volume of the thorax decreases and intercostal muscles contract causing pressure to increase.
Air flows out to equalize pressure gradient.

34. Topic 6: Human Health and Physiology
Nerves, Hormones, and Homeostasis

35. State that the nervous system consists of the central nervous system (CNS) and peripheral nerves, and is composed of cells called neurons that can carry rapid electrical impulses.
The nervous system consists of the central nervous system (CNS) and peripheral nerves, and is composed of cells called neurons that can carry rapid electrical impulses.

36. Draw and label a diagram of the structure of a motor neuron.
Include:
dendrites,
cell body with nucleus,
Axon
myelin sheath
nodes of Ranvier
motor end plates (axon terminals).

37. State that nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by relay neurons, and from the CNS to effectors by motor neurons.
Nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by relay neurons, and from the CNS to effectors by motor neurons.

38. The Resting Potential of a Neuron
Define resting potential and action potential (depolarization and repolarization).
The Resting Potential of a Neuron
The cell membrane of a neuron has charged particles (ions) on either side.
When the neuron is at rest (not actively transmitting an impulse), the outside of the membrane has a net positive charge because it has more positive ions than negative ones.
The inside has a net negative charge, because it has more negative ions than positive ones.
A membrane potential is simply a voltage that exists across a membrane due to this unequal distribution of charges.
When a neuron is at rest, the resting potential is about -70 millivolts (mV), indicating that the inside is negative relative to the outside.
The reason that the resting potential can exist is because cell membranes are impermeable and do not allow the flow of ions in and out of the cell except through ion-specific channels.

39. Define resting potential and action potential (depolarization and repolarization).
An action potential occurs when a neuron sends information down an axon, away from the cell body.
The action potential is an explosion of electrical activity that is created by a depolarizing current.
A stimulus causes the resting potential to move toward 0 mV. When the depolarization reaches about -55 mV a neuron will fire an action potential. This is the threshold.
If the neuron does not reach this critical threshold level, then no action potential will fire.
Also, when the threshold level is reached, an action potential of a fixed sized will always fire...for any given neuron, the size of the action potential is always the same.
There are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired - this is the "ALL OR NONE" principle.

40. Explain how a nerve impulse passes along a non-myelinated neuron.
In resting neurons, there exists an imbalance of ions inside and outside of the cell membranes.
The important ions are K+ (potassium) and Na+ (sodium).
K+ is more concentrated inside the cell and therefore tends to diffuse out of the cell.
It is this diffusion that causes the charge potential across the plasma membrane (in resting neurons it is about -70 mV).
Na+ is more concentrated outside of the cell and thus tends to diffuse into the cell, but at a very slow rate due to the low permeability of the plasma membrane to Na+.
Sodium-potassium pumps embedded in the plasma membrane work against both ions' diffusion gradients in order to preserve the gradients and the membrane potential.

41. Explain the principles of synaptic transmission.
Include the release, diffusion and binding of the neurotransmitter, initiation of an action potential in the post-synaptic membrane, and subsequent removal of the neurotransmitter.

42. Explain the principles of synaptic transmission.
Step 1. The neurotransmitter is manufactured by the neuron and stored in vesicles at the axon terminal.
Step 2. When the action potential reaches the axon terminal, it causes the vesicles to release the neurotransmitter molecules into the synaptic cleft.
Step 3. The neurotransmitter diffuses across the cleft and binds to receptors on the post-synaptic cell.
Step 4. The activated receptors cause changes in the activity of the post-synaptic neuron.
Step 5. The neurotransmitter molecules are released from the receptors and diffuse back into the synaptic cleft.
Step 6. The Neurotransmitter is re-absorbed by the post synaptic neuron. This process is known as Reuptake.

43. State that the endocrine system consists of glands that release hormones that are transported in the blood.
The endocrine system consists of glands that release hormones that are transported in the blood.

44. State that homeostasis involves maintaining the internal environment between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance.
Homeostasis involves maintaining the internal environment between limits, including:
blood pH
carbon dioxide concentration
blood glucose concentration
body temperature
water balance

45. This sends information to an effector, which then takes action.
Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms.
Homeostasis involves maintaining the body in an environment between narrow limits by negative feedback mechanisms.
Negative feedbacks contain a detector which measures the value of a feature to be controlled.
This sends information to an effector, which then takes action.

46. Sweating can cool the body as moisture on skin evaporates.
Explain the control of body temperature, including the transfer of heat in blood, and the roles of the hypothalamus, sweat glands, skin arterioles and shivering
Blood near the skin exchanges heat with the environment to preserve 37°C temperature.
Vasoconstriction can decrease blood flow to the skin, preserving heat in cold weather.
Sweating can cool the body as moisture on skin evaporates.
Shivering produces muscle heat.

47. Explain the control of blood glucose concentration, including the roles of glucagon, insulin and α and β cells in the pancreatic islets.
Glucagons - released by Alpha cells in the pancreatic islets when blood sugar is low, it transforms stored glycogen into glucose that enters the blood stream.
Insulin - released by Beta cells in the pancreatic islets when blood sugar is high, it transforms glucose in blood to stored glycogen.

48. Distinguish between type I and type II diabetes.
Type 1 diabetes is usually diagnosed in children and young adults, and was previously known as juvenile diabetes. 
The body does not produce insulin.
Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life.
Only 5-10% of people with diabetes have this form of the disease. 
With the help of insulin therapy and other treatments, even young children with type 1 diabetes can learn to manage their condition and live long, healthy, happy lives.
Type 2 diabetes is the most common form of diabetes.
The body does not produce enough insulin or
The cells ignore the insulin.
When glucose builds up in the blood instead of going into cells, it can lead to diabetes complications.

49. Topic 6: Human Health and Physiology
Reproduction

50. Draw diagrams of the adult male and female reproductive systems.

51. Draw diagrams of the adult male and female reproductive systems.

52. Outline the role of hormones in the menstrual cycle, including Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), estrogen and progesterone.
Estrogen leads to the production of eggs, which leads to the menstrual cycle.
In the menstrual cycle, FSH secreted by pituitary gland increases, this is responsible for the growth of an oocyte (an immature egg) and it's follicle.
Two weeks after the start of menstruation, ovulation occurs due to a sudden and sharp increase in LH from the pituitary gland.
It also causes the empty follicle to develop into the yellow body (corpus luteum) which starts releasing the hormone progesterone.
This is responsible for maintaining and thickening the endometrium (wall of the uterus) in preparation for implantation.

53. Annotate a graph showing hormone levels in the menstrual cycle, illustrating the relationship between changes in hormone levels and ovulation, menstruation and thickening of the endometrium.

54. Hormone levels in the menstrual cycle
changes in hormone levels and:
ovulation
menstruation
thickening of the endometrium

55. List three roles of testosterone in males.
From birth to the age of ten, testosterone level is very low,increasing sharply after that and begins puberty in males.
This is when sperm production takes place.
Testosterone stays at high levels until the age of 40-50, then it gradually decreases.
It is also responsible for:
voice change,
hair growth in certain parts of the body
building of muscles.

56. Outline the process of in vitro fertilization (IVF).
Various drugs are injected one a day for three weeks to stop the menstrual cycle.
Large doses of FSH are injected to stimulate ovaries to develop many follicles.
HCG hormone is injected 36 hrs. before cell collection, causing the eggs to mature and loosen.
Eggs are removed from the ovaries of a woman by suction through the vagina and are placed in a glass dish. The eggs are then cleaned to remove blood and other unwanted material. The egg is then incubated.
A male provides sperm which is collected by a doctor.
The healthiest sperm are selected and mixed with the egg, to force fertilization.
Two or three eggs are selected and implanted in the uterus through the vagina.
After a few weeks, a pregnancy test is administered.
Later in the pregnancy, a scan is conducted to find a heartbeat.

57. Discuss the ethical issues of IVF.
For IVF
Childless and infertile couples are provided a means to have children.
Suffering due to a genetic disease of infertility is reduced.
Against IVF
There is a high probability that children conceived using IVF from infertile parents would inherit this genetic disease, going against natural selection.
Spare embryos are killed or donated to stem cell research.
Once fertilized embryos have been implanted in the uterus, the parents have the option of choosing which eggs shall be removed, essentially allowing humans the right to define life and death.
Those who do not remove extra eggs from the uterus have multiple births, increasing the risk of health problems for the fetus.