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45 Cards in this Set
- Front
- Back
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6.1.1 Explain why digestion of large food molecules is essential
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Food is taken into our body in large insoluble parts. In order to get the nutrients into out body they need to be digested and converted into smaller soluble products
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6.1.2 Explain the need for enzymes in digestion
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These are biological catalysis, which speed up reactions by lowering the activation energy. Making sure that the reaction in the bodies take place quickly at suitable temperatures at independent times.
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6.1.3 State the source, substrate, product and optimal pH conditions for one amylase, one protease and one lipase
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Amylase- Salivary amylase, Salivary glands, Starch into Maltose, pH 7
Protease- Pepsin, Stomach, Protein into Amino acids, pH 2-3 Lipase- Pancreatic lipase, Pancreas, Lipids into Glycerol and Fatty acids, pH 8 |
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6.1.4 Draw and label a diagram of the human digestive system
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6.1.5 Outline the function of the stomach, small intestine and large intestine
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Stomach-
• This is where the food is stored and proteins starts to be broken down • When the food enters the stomach the gastric glands secret the digestive juices • This secretion is controlled by gastrin (a hormone) • Acid (hydrochloric) is used to kill pathogens entering our body • This mean the stomach is around pH 2 • Mechanical action of stomach churn food, helping digestion • This continues until the food is a creamy past called chyme Small intestines- • This is where the unable nutrients are absorbed • The gall bladder secretes bile into the small intestine • This emulsifies lipids and neutralizes the pH • The pancreas then secretes digestive enzymes • Muscles throughout the small intestine mix and move food • Hey also contain small pits- crypts of lieberkunn- which secretes other digestive juices Large intestines- • Absorbs the rest of the water • Converting what is left from semi solid to solid sate • The facieses is then stored in the rectum and excreted |
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6.1.6 Distinguish between absorption and assimilation
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Absorption is the movement of the fluid or dissolved substance across a membrane. Whereas assimilation is the conversion of nutrients into parts of an organism
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6.1.7 Explain how the structure of the villus is related to its role in absorption and transport of products of digestion
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Microvilli greatly increase the surface area of the villi, allowing for
grater absorption Rich capillary network- help to maintain a constant concentration gradient, so absorption occurs at a fast rate Single layer epithelial layer- ensures a minimal diffusion distance Lacteals- absorb lipids straight from the small intestines into the lymphatic system Crypts- located between villi and release juices that act as nutrient carrier fluid Membrane mitochondria- provide energy for active transport into cells, to ensure the flow is constant |
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6.2.1 Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of the blood through the heart
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6.2.2 State that coronary arteries supply heart muscle with oxygen and nutrients
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Small arteries called coronary arteries sound the heart; they supply the heart with:
- Oxygen -ATP - Nutrients |
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6.2.3 Explain the action of the heart in terms of collecting blood, pumping blood and opening and closing valves
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• Our transport system is double circulatory
• Deoxygenated blood enters the heart from the right atrium via the vena cava • This then contracts and the tricuspid valve opens moving blood from the atrium to the ventricles • The tricuspid valve then closes then the ventricle contracts, opening the pulmonary valve and the blood is forced out the heart to the lungs through the pulmonary artery • Once the blood has been re-oxygenated by the lungs it enters the heart from the second time this time into the left atrium via the pulmonary vein • Again this contracts opening bicuspid valve and the blood is forced into the left ventricle • The aortic valve then opens when the ventricle contracts and the blood then leaves heart to the rest of the body via the aorta |
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6.2.4 Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline)
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- The hear muscle can contract of its own accord. This property is called myogenic.
- The pacemaker is a small patch of special muscle tissue on the wall of the right atrium near the point where the vena cava enters. It releases an electrical impulse approx. 70 times per minute. This causes the heart muscle to contract. Involuntary nerves from the cardiac control center in the medulla of the brain are attached to the pacemaker. - Impulses down the cardiac depressor nerve cause the heart rate to slow down. e.g during sleep. - Impulses down the cardiac accelerator nerve cause the heart rate to speed up. e.g during exercise. - The hormone adrenalin from the adrenal gland stimulates the pacemaker to increase output. |
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6.2.5 Explain the relationship between the structure and function of arteries, capillaries and veins
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• Arteries-
-Carry blood at high pressure (80-120mm Hg) -Have a narrow lumen (maintaining pressure) -The middle layer contains muscle and elastin -Outer layer contains collagen to prevent rupturing • Veins- -Carry blood at lower pressure (<10mm Hg) -They have a large lumen -Walls that surround are all very thin -They have valves stopping blood pooling at extremities • Capillaries- -Involved in gas exchange within the body tissue -Pressure is very low (-15mm Hg) -The walls are single cell thick -Can contain pores to aid the transport of material |
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6.2.6 State that blood is composed of plasma, erythrocytes, leukocytes (phagocytes and lymphocytes) and platelets
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Blood is made up of-
• Plasma • Erythrocytes (red blood cells) • Leukocytes (white blood cells) • Platelets |
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6.2.7 State that the following are transported by blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
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The blood transports-
Nutrients -Antibodies -Carbon Dioxide -Hormones -Oxygen -Urea -Heat |
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6.3.1 Define pathogen
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A pathogen is a disease causing microorganism, virus or prion
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6.3.2 Explain why antibiotics are effective against bacteria but not against viruses
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• Antibiotics are a drug that kill pathogens
• They do this by taking advantage that bacteria are prokaryotic while human cells are eukaryotic • There are two main types of antibiotics -ones that block protein synthesis channels -ones that prohibit the growth of cell walls • This is why the antibiotics also do not work on viruses |
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6.3.3 Outline the role of skin and mucous membranes in defence against pathogens
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Our first line of defense is the physical surface barrier that block the entry of pathogens
• The Skin -This protects all external structures -The epidermis is a dry, thick, tough barrier made up of dead cells -The dermis contains- sweat glands, sebaceous glands and sensory receptors -The skin is slightly acidic due to bodily secretions • Mucous membranes -Protects internal structures like the trachea, nasal passage, urethra and vagina -It’s a region that contains living cells that trap and secrete fluid in order to remove bacteria -It also contains enzymes like lysosomes, which damage the pathogens |
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6.3.4 Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissue
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Macrophages are a type of leucocyte that is part of the second line of defense.
Through a process called phagocytosis a macrophage will identify a non-self pathogen an then engulf it. As it’s not engulfing a specific pathogen this is called non-specific immunity. As the Macrophage can change shape it is able to move in and out of the blood vessels, meaning that the process can take place anywhere. |
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6.3.5 Distinguish between antigens and antibodies
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Antigens- A protein substance that the body regencies as foreign and that can evoke an immune response
Antibodies- Produces in lymphocytes is response to a specific antigen |
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6.3.6 Explain antibody production
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Each B-lymphocyte will produce a specific antibody for an antigen. This is why this is called the specific immune response.
-When an antigen is detected the right B lymphocyte also has to be detected -When it does it starts to clone -They can start to produce lots of antibodies, which kills the pathogens -By the end some of the B lymphocytes are left and they stay in the blood as memory cells |
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6.3.7 Outline the effect of HIV on the immune system
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• HIV stands for human immunodeficiency virus
• It’s a known as a retro virus, which causes reverse transcriptase • This allows the HIV DNA to produce though the RNA of the host cell • It effect the T-helper cells which start the production of antibodies • This can remain in your body inactive for many years • When the number of T-helper cells in your body drops below a set level you are re-diagnosed with AIDS |
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6.3.8 Discuss the cause, transmission and social implications of AIDS
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• AIDS stands for Acquired immunodeficiency syndrome
• AIDS does not have it’s own set of symptoms • Instead it’s a collection of symptoms of diseases that are not being fought of by the damaged immune system • Similarly die of AIDS you die of a diseases that you are unable to fight off • AIDS is transmitted via the exchange of bodily fluid • This includes activities such as- unprotected sex, blood transfusion, breastfeeding and child birth • The risk can be reduced by the use of condoms • People with aids are often decimated against • They are left unemployed as a result of this • AIDS has the ability to cripple economies and cause an increase of orphans • AIDS cases increase in area of poverty due to lack of education |
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6.4.1 Distinguish between ventilation, gas exchange and cell respiration
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Ventilation- The exchange of air between the lungs and the atmosphere
Gas exchange- The exchange of oxygen and carbon dioxide n the alveoli and the blood stream Cell Respiration- the release of ATP form organic materials |
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6.4.2 Explain the need for a ventilation system
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A passive process that keeps that keep a constant gradient so that oxygen and carbon dioxide can move efficiently through the body for cell respiration.
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6.4.3 Describe the features of alveoli that adapt them to gas exchange
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The alveoli has been specially adapted in order to make the diffusion quicker
-Thin Wall: made of a single layor of cells so the distance is smaller -Rich capillary network: to keep a high gradient -Increase Sa:Vol ratio: rounded shape allows high amounts of exchange to take place at one time -Moist: The linings secrete fluid, which allows the gases to dissolve into it |
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6.4.4 Draw an label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli
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6.4.5 Explain the mechanism of ventilation of the lungs in terms of volume and pressure changes caused by the internal and external intercostal muscles, the diaphragm and abdominal muscles
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Inhalation
-diaphragm contracts and flattens -intercostal muscles contract, moving ribs up and out - The volume is increased -The pressure is therefore low -So the air is drawn In Exhalation -diaphragm relaxes and curve upwards intercostal msucles Relax, moving ribs down and in -Abdominal muscles Contract, pushing diaphragm up - Volume is reduced - The pressure is therefore High - The air moves out |
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6.5.1 State that the nervous system consists of the central nervous system (CNS) and peripheral nerves, and is composed of cells called neurons that carry rapid electrical impulses
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Central nervous system- made up of the brain and spinal cord
Peripheral nervous system- made up of peripheral never which link to the CNS with the bodies receptors |
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6.5.2 Draw and label a diagram of the structure of the motor neuron
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6.5.3 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
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6.5.4 Define resting potential and action potential (depolarisation and repolarisation)
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Resting potential- the charge difference across the membrane when a neuron is not firing (-70mV), as maintained by the sodium-potassium pump
Action potential- the charge difference across a membrane when a neuron is firing Depolarization- The change from a resting potential to an action potential caused by the opening of the sodium channels Repolarization- The change from an action potential to a resting potential |
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6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
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• A neuron stars at resting potential
• This kept constant by a Na/K pump, which pumps 3 Na+ out for every 2K+ pumped in • When a charge is sent down the neuron NA+ voltage gated channels open • There is then an influx of NA+ into the neuron and the inside because relatively positively charged • This is known as depolarization • This change in charge causes the K+ voltage gated channels to open • The K+ ions then flow out of the neuron and the inside returns back to negative • The K+ ions and the NA+ ions then need to be readjusted before another impulse can travel through • Thus making sure that the impulse travels in only one direction • The time taken before the next impulse can be fired is called the refraction period |
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6.5.6 Explain the principles of synaptic transfer
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The synapse is the gap between two neurons. The ends of one neuron are called the pre-synaptic and the start of the neuron after the synapse is called the post-synaptic neuron. Because action potential can’t travel across the gap a chemical is released instead. This chemical is known as a neurotransmitter.
1. When an action potential reaches the pre-synaptic neuron the voltage gated Ca+ channel is opened 2. The Ca+ ions then move in via diffusion, prompting the vesicles containing neurotransmitters to fuse with the plasma membrane 3. The neurotransmitters are then admitted via exocytosis from the axon terminal across the clef 4. After moving across they bond to the neuron acceptors on the post-synaptic neuron Opening the Na+ channels 5. The depolarizes the neuron and starts the impulse movement back though the next neuron 6. The neurotransmitters are then sent back to be retaken up by a neurotransmitter pump or broken down by enzymes |
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6.5.7 State that the endocrine system consists of glands that release hormones that are transported in the blood
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This is a type of ductless gland that creates hormones, which it secretes directly into the blood stream. In the blood it travels to target cells and causes mainly slow and long-term effects.
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6.5.8 State that homeostasis involves maintaining the internal environment between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance
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The controlling of a contestant internal environment
As humans we control five main conditions in out bodies • Body temperature (35-38) • Blood pH (7.35-7.45) • Carbon dioxide concentration (35-45) • Blood glucose level (75-95) • Water balance |
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6.5.9 Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms
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− This is the main way of controlled homeostasis
− Specialist receptors pick up a change in internal conditions − Generating the opposite to occur to counteract the change − When an equilibrium is receptor the effector will stop the response − If the levels have gone too far in the opposite direction; agnostic pathways are activated |
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6.5.10 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
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Animals that can regulate their body temperature are called hymetherms. This is controlled by the part of the brain called the hypothalamus. You skin works as the thermo receptor and relays this information to the hypothalamus.
When we get too cold we- − Shiver to generate the production of ATP − Hairs stand of end to trap insulating layer of air − Vasoconstriction so there is less radiation from the blood When we get too hot- − Activate the sweat gland to loss heat via evaporation − Hairs are flat to make sure not air is trapped − Vasodilatation so radiation form the blood is increased |
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6.5.11 Explain the control of blood glucose concentration, including the roles of glucagon, insulin and the alpha and beta cells in the pancreatic islets
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Your blood glucose level is the consternation of glucose dissolved in blood plasma. It’s need to carry our cell respiration, although we can have to much or too little in our bodies at one time. When we have too much we risk hypoglycemia. For this reason care need to be taken by our bodies to control this amount. We use insulin and glucagon hormones to control this. The are known as antagonistic (they have the opposite effects of each other). They are both produced in the pancreases.
When glucose levels are too high- − Beta cells are released from the pancreas, causing the production of insulin − This causes more glucose to be taken in by cells − The blood is also then directed to the liver where is to converted from glucose to glycogen (glycogenesis) When the glucose levels are too low- − Alpha cells are released from the pancreas, causing the production of glucagon − This causes less glucose to be taken in by cells − The blood is also then directed to the liver where |
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6.5.12 Distinguish between type I and type II diabetes
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Type I-
− Insulin- dependent − Non-insulin dependent − Usually occurs in childhood − Usually occurs in adulthood − Body does not produce sufficient amount of insulin Type II − Body does not respond to insulin − Caused by the destruction of beta cells − Caused by the down-regulation of insulin receptors − Controlled by insulin injections − Controlled by diet |
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6.6.1 Draw and label diagrams of the adult male and female reproductive systems
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6.6.2 Outline the role of hormones in the menstrual cycle, including FSH (follicle stimulating hormone), LH (luteinising hormone), estrogen and progesterone
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FSH- stimulates follicular growth and stimulates the production of estrogen
Oestrogen- develops the endometrium simulates LH and FSH at high levels and inhibits them at low levels LH- surge causes ovulation, causing coups luteum which stimulates progesterone Progesterone- maintain the endometrium lining and inhibits FHS and LH |
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6.6.3 Annotate a graph showing hormone levels in the menstrual cycle, illustrating the relationship between changes in hormone levels and ovulation, menstruation and the thickening of the endometrium
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1. A small peak of FSH causes the production of estrogen that start the building up of the endometrium lining and inhibits LH and FSH at low levels
2. At around day 12 the amount of estrogen is increased so much that FSH and LH is produced. 3. This starts the development of an egg follicle and on day 14, when LH peaks, the egg is released into the uterus 4. This leaves a corpus luteum which start the production of estrogen and progesterone which will maintain the endometrium this also inhibits LH and FSH 5. If he egg doe not get fertilized the corpus luteum will start to brake down and estrogen and progesterone will stop being produced leading to the braking down of the endometrium lining 6. FSH and Lh are no longer prohibited and the cycle starts again |
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6.6.4 List three roles of testosterone in males
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Testosterone is the main sex hormone in men it-
• Develops male genitalia • Develops secondary sex characteristics • Maintains a strong sex drive |
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6.6.5 Outline the process of in vitro fertilisation
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IVF provides chances for people who are having trouble conceiving this could be due to low sperm counts, impotence, blocking of the fallopian tubes or abnormal ovulation. It can also be used to give people a chance to conceive without having sex with the person. This can be used in cases such as sperm donors and diseased partners. The following steps are used in IVF-
S- stops the natural cycle H- hormone injections of FHS and hCG, these start the maturation of the egg follicles E- extracts the eggs from the ovaries S- sperm is selected and prepared before being inserted into the egg via an intra-cytoplasmic injection F- fertilization takes place normally under controlled conditions I- implantation of multiple embryos T- test are done to see if the pregnancy was successful |
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6.6.6 Discuss the ethical issues associated with IVF
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Advantages
Chance for inertial couples Screening allows only healthy embryos Eggs can be stored Disadvantages Expensive Low success rate Could lead to ‘designer babies’ Lead to multiple births Seen by many as ethically wrong |
