Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/47

Click to flip

47 Cards in this Set

  • Front
  • Back
1 Explain why digestion of large food molecules is essential
- Large molecules cannot pass through the wall of the villus.
- Large molecules, especially proteins, can stimulate an antibody reponse.
- Large molecules need to be broken down into their constituant units in order to be reassembled in the way the body wants.
Explain the need for enzymes in digestion
1. Enzymes are needed as they break down the large food molecules into smaller ones so that these can eventually be absorbed.
2. Digestion can occur naturally at body temperature, however this process takes a very long time as it happens at such a slow rate. For digestion to increase in these circumstances, body temperature would have to increase as well. However this is not possible as it would interfere with other body functions.This is why enzymes are vital as they speed up this process by lowering the activation energy required for the reaction to occur and they do so at body temperature.
State the source, substrate, products and optimum pH conditions for one amylase, one protease and one lipase
Enzyme group: Example: Source: Substrate: Products: Optimum pH

Amylase: Amylase: Salivary gland: Starch: Maltose: 7.2

Protease: Pepsin: Stomach wall: Protein: Peptides: 2

Lipase: Pancreatic lipase: Pancreas: Lipid: Glycerol fatty acids: 8
Draw and label a diagram of the digestive system
.
Outline the function of the stomach, small intestine and large intestine
Stomach: secretes hydrochloric acids which helps destroy pathogens and bacteria, HCL provides the optimum pH for pepsin, secretes pepsin for protein digestion.

Small intestine:main digestive region, pancreas releases digestive juice here, Bile from liver released here, wall secretes enzymes, all food groups digested, main absorptive region, has villi for absorption of food particles

Large intestine: Water absorptive region, large number of bacteria help protect the gut from pathogens, bacteria synthesise vitamin K and vitamin H, moves material that has not been digested along, produces faeces
Distinguish between absorption and assimilation
Absorption occurs when the food molecules pass through a layer of cells and into the bodies tissues. This occurs in the small intestine which has many villi that are specialised for absorption.
Assimilation occurs when the food molecules becomes part of the bodies tissue. Therefore, absorption is followed by assimilation.
Explain how the structure of the villus is related to its role in absorption and transport of the products of digestion
.
Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart
.
State that the coronary arteries supply heart muscle with oxygen and nutrients
The coronary arteries supply heart muscle with oxygen and nutrients
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves
- Left atrium collects oxygenated blood from pulmonary vein.
- Right atrium collects deoxygenated blood from vena cava.
- Atria pump blood into ventricles.
- Right ventricle pumps deoxygenated blood out of the heart into arteries.
- Left ventricle pumps oxygenated blood to body via aorta. Left ventricle pumps under higher pressure than right ventricle.
- When ventricles contract, blood pressure closes bicuspid and tricuspid valves.
- When ventricles relax, backflow closes semilunar valves.
- Coronary arteries carry oxygenated blood to the heart muscle.
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
- 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 impuls approx 70 times per minute. This causes the heart muscle to contract. Involuntary nerves from the cardiac control centre 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 excercise.
- The hormone adrenalin from the adrenal gland stimulates the pacemaker to increase output.
Explain the relationship between the structure and function of arteries, capillaries and veins
.
State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets
Blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets
State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
The following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
Define pathogen
Pathogen: an organism or virus that causes a disease.
Explain why antibiotics are effective against bacteria but not against viruses
1.Antibiotics block specific metabolic pathways in bacteria.
2.Bacteria are very different to human cells so human cells are not affected.
3.Viruses require host cell to carry metabolic processes for them and so antibiotics cannot be used to treat viruses.
4.Harming the virus would harm the human cells.
Outline the role of skin and mucous membranes in defence against pathogens
Skin:
- Waterproof surface layer, tough, elastic (physical barrier)
- Oily secretion (sebum) from sebacious gland in hair follical controls funcal and bacterial growth and stops skin cracking

Mucous membranes:
- IN air passages, traps pathogens, swept up to throat to be swallowed
- In vagina, acidic to prevent growth of pathogens
Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissues
- Phagocytic leucocytes destroy pathogens in the blood and tissue fluid.
- They ingest the pathogens by phagocytosis.
- Lysosomes in the phagocyte release digestive enzymes.
- Pathogens are destroyed by the digestive enzymes.
- Phagocytic leucocytes can also push their way through capillary walls into tissue fluid. This is especially important for controlling infection from cuts and scratches.
Distinguish between antigens and antibodies
- An antigen is a chemical foreign to the body that brings about an immune response.
- An antibody is a specific protein produced by lumphocytes in response to an antigen. An antibody binds to its antigen and brings about its destruction.
Explain antibody production
1. There are many lumphocyte (a type of leukocyte that makes antibodies) types each has a different antibody on its surface.
2 .Pathogen have antigens on their surface.
3.The antibody selects the antigen, and binds to it.
4.Lymphocyte becomes active and makes clones of itself.
5.The clones make more of the specific antibody.
6. The pathogen is destroyed.
Outline the effects of HIV on the immune system
- The activation of lymphocytes in the production of antibodies requires another type of white blood cell called a helper cell.
- HIV destroys these helper cells.
- THe lymphocytes cannot divide to form a clone of the antibody-producing cells.
- Antibodies are not produce, and the pathogen survives to cause an infection.
- Infections begin to accumulate in the body.
Discuss the cause, transmission and social implications of AIDS
Cause: HIV - Human Immunodeficiency Virus
Transmission: unprotected sexual intercourse, breast feeding, placenta, blood transfusion, contaminated needles.
Social implications: breakdown of family structure, huge drain on medical resources, huge loss of workforce.
Distinguish between ventilation, gas exchange and cell respiration
Ventilation:
Breathing air in and out of the lungs.
Cell respiration:
The chemical breakdown of sugar in cells, with the use of enzymes to release energy.
Gas exchange:
In lungs - diffusion of oxygen from alveoli into blood, diffusion of carbon dioxide from blood into alveoli.
In tissues - diffusion of oxygen from blood into tissue, diffusion of carbon dioxide from tissue cells into blood.
Explain the need for a ventilation system
- A ventilation system is needed to maintain the concentration gradients of gases in the alveoli.
- Diffusion of gases occurs due to the concentration gradient of oxygen and carbon dioxide between the alveoli and the blood.
- The body needs to get rid of carbon dioxide which is a product of cell respiration and needs to take in oxygen as it is needed for cell respiration to make ATP.
- To do so there must be a low concentration of carbon dioxide in the alveoli so that carbon dioxide can diffuse out of the blood in the capillaries and into the alveoli. Also there must be a high concentration of oxygen in the in the alveoli so that oxygen can diffuse into the blood in the capillaries from the alveoli.
- The ventilation system makes this possible by getting rid of the carbon dioxide in the alveoli and bringing in more oxygen.
Describe the features of alveoli that adapt them to gas exchange
1.Large surface area for gas exchange.
2.Wall is made up of single layer of flattened so diffusion distance is small allowing rapid gas exchange.
3.Covered by a dense network of capillaries which have low oxygen and high carbon dioxide concentrations. This allows oxygen to diffuse into the blood and carbon dioxide to diffuse out of the blood.
4.Some cells in the walls secrete fluid allowing gases to dissolve.
1.Great numbers increase the surface area for gas exchange.
2.Wall made up of single layer of cells and so are the walls of the capillaries so diffusion distance is small allowing rapid gas exchange.
3.Covered by a dense network of capillaries which have low oxygen and high carbon dioxide concentrations. This allows oxygen to diffuse into the blood and carbon dioxide to diffuse out of the blood.
4.Some cells in the walls secret fluid allowing gases to dissolve. Fluid also prevents the sides of alveoli from sticking together.
.
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
Breathe In:
- External intercostal muscles are attached to the rib cage. When they contract the rib cage moves up and out. This causes the volume to increase, and the pressure to decrease, sp breathe in.
- The diaphragm is a dome-shaped structure separating thoracic cavity from abdominal cavity. When radial muscle contracts, dome flattens. This causes the volume to increase, and the pressure to decrease, so breathe in.
Breathing out:
- The internal intercostal muscles are attached to the rib cage. When contracted, the rib cage moves down and in, causing the volume to decrease, and the pressure to increase, so breathe out.
- The abdominal muscles. When radial muscles of diaphragm relax, abdominal muscles contract and push diaphragm back to dome shape. Volum decreases, and pressure increases, so breathe out.
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
Draw and label a diagram of the structure of a motor neuron
.
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
Define resting potential and action potential (depolarization and repolarization)
Resting potential: the electrical potential across the plasma membrane of a cell that is not conducting an impulse.

Action potential: The reversal and restoration of the electrical potential across the plasma membrane of a cell, as an electrical impulse passes along it.
Explain how a nerve impulse passes along a non-myelinated neuron
1.Resting potential rises above threshold level.
2.Voltage gated sodium channels open.
3.Sodium ions flow into the cell, more sodium channels open.
4.Inside of cell develops a net positive charge compared to the outside and results in depolarization.
5.Voltage gated potassium channels open.
6.Potassium ions flow out of the cell.
7.Cell develops a net negative charge compared to the outside and results in repolarization.
8.Concentration gradients restored by sodium-potassium pumps.
9.Resting potential is restored.
Explain the principles of synaptic
transmission
1. Sodium ions enter the auxoplasm through a voltage-gated sodium ion channel when the action potential arrives at the synapse.
2. This opens the voltage gated calcium ion channels.
3. The influx of calcium ions causes vesicles of neurotransmitter to move to the pre-synaptic membrane and burst.
4. The calcium ions are removed by an active pump.
5. Neurotransmitter diffuses across the synaptic gap and binds to a specific receptor on the post-synaptic membrane.
6. This opens the chemical gated channel, allowing an influx of sodium ions, which causes depolarisation.
7. The neurotransmitter is removed and taken through the pre-synaptic membrane and re-synthesised into neurotransmitter. Some neurotransmitters are broken down by an enzyme in the synaptic gap before uptake
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
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 (blood and tissue fluid) between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance
Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms
- Receptors monitor the level of a variable
- Co-ordinating centre regulates the level of the variable
- Effectors bring about the changes directed by the co-ordinating centre

Deviation from norm --> receptor --> co-ordinating centre --> effectors --> return to norm
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 temperature is monitored by the hypothalamus. The hypothalamus also recieves information from temperature receptors in the skin. Nerve impulses are sent from the hypothalamus to co-ordinate the processes.
Hot: - Skin arterioles increase in diameter so that more blood flows to the skin, transferring heat from the core of the body to the skin so that heat is lost to the external environment.
- Skeletal muscle stays relaxed so that heat is not generated.
- Sweat glands secrete large amounts of sweat. When water evaporates from the moist skin it cools down the body.
Cold: - Skin arterioles decrease in diameter so that less blood flows to the skin. The diameter of the capillaries in the skin cannot change but less blood flows through them. This prevents heat loss to the external environment as the temperature of the skin falls.
- Shivering occurs. This is when the skeletal muscle does many small rapid contractions to generate heat.
- Sweat glands to not secrete sweat and so no water evaporation can occur as skin stays dry.
Explain the control of blood glucose concentration, including the roles of glucagon, insulin and α and β cells in the pancreatic islets
.
Distinguish between type I and type II diabetes
Type 1:
Usually starts early in life, due to loss of insulin secreting cells in the pancreas, controlled by testing lood sugar levels and then injuecting appropriate quantity of insulin, control has to continue throughout lifetime.
Type 2: Comes on gradually, usually in middle age, often associated with long term overweight, persistent over-eating of sugary foods causes high levels of plasma insulin, this reduces the sensitivity of the insulin targe cells, often controlled by reducing carbohydrate intake, allowing the target cells to recover.
Define diabetes
Diabetes: the failure to control blood glucose level leading to abnormally high levels of glucose in the blood
Draw and label diagrams of the adult female reproductive system
.
Draw and label diagrams of the adult male reproductive system
.
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
.
List three roles of testosterone in males
1. pre-natal development of male genitalia
2. Development of secondary sexual characteristics
3. Maintenance of sex drive
Outline the process of in vitro fertilization (IVF)
1. FSH is injected into the woman in order to induce development of several follicles in the ovaries
2. Eggs from mature follicles are removed several days later by a tube inserted via the vagina
3. The eggs are transferred to a dish of warmed physiological saline and the sperms of the man are added
- After a few days incubation, the embryos are examined for any abnormalities
- Hormonal treatment prepares the mother's uterus
- Selected embryos are the inserted into the mother's womb
Discuss the ethical issues associated with IVF
Positive: may allow childless couples to have a child, screening and selection prevents genetic abnormalities from being passed on.

Negative: more embryos than are used are produced, so some die, if more than one selected embryo implants then multiple births can affect the health of the children, inherited forms of infertility may be passed on, may lead to abuse by selecting embryos other than for avoiding genetic abnormalities.
Outline the role of hormones in the menstrual cycle, including FSH (follicle stimulating hormone), LH (luteinizing hormone), estrogen and progesterone
FSH released from anterior pituitary:
- stimulates growth of follicle
- Stimulates secretion of estrogen
Estrogen released from follicle cells:
- stimulates repari and growth of endometrium
- negative feedback on pituitary to block FSH release
- nearing middle cycle it reaches a critical level which causes a positive feedback on pituitary to release LH
LH released from anterior pituitary:
- stimulates ovulation
- stimulates converstion of empty follicle to corpus luteum
- stimulates secretion of estrogen and progesterone by corpus luteum
Progesterone released from corpus luteum:
- stimulates final growth of uterus lining
- Negative feedback block FSH and LH