Revision 3 Flashcards
Give 1 example of a Barrier Method of Contraception.
3 marks
E.g. Condom, Female Condom or Diaphragm.
True or False? Barrier Methods of Contraception protect against Sexually Transmitted Infections (STI’s).
(3 marks)
True. Barrier Methods of Contraception do, but Hormonal Methods don’t.
The Combined Pill contains Oestrogen and Progesterone.
Explain how the Combined Pill reduces fertility.
(11 marks)
Taking Oestrogen every day means the levels of Oestrogen in the Blood are kept high. This inhibits the production of FSH and so stops an Egg from developing.
Progesterone reduces fertility by stimulating the production of thick Cervical Mucus which stops Sperm getting through the entrance to the Uterus and reaching an Egg.
Give 1 advantage and 1 disadvantage of Hormonal Contraceptive Methods.
(9 marks)
Advantage: e.g. when used correctly, Hormonal Methods are more effective at preventing pregnancy than Barrier Methods. With Hormonal Methods, the couple don’t stop and think about contraception each time they have intercourse.
Disadvantage: e.g. Hormonal Methods can have unpleasant side effects. And they don’t protect against STI’s.
Give 1 advantage of Hormonal Contraceptive Methods.
5 marks
E.g. when used correctly, Hormonal Methods are more effective at preventing pregnancy than Barrier Methods.
With Hormonal Methods, the couple don’t stop and think about contraception each time they have intercourse.
Give 1 disadvantage of Hormonal Contraceptive Methods.
2 marks
Hormonal Methods can have unpleasant side effects. And they don’t protect against STI’s.
Explain how Clomifene Therapy helps women who don’t Ovulate.
(5 marks)
Taking Clomifene causes more FSH and LH to be released by the Body, which stimulate Egg Maturation and Ovulation.
Meera is undergoing IVF Treatment. At which point in the IVF Process is Meera given the hormones FSH and LH?
Explain why Meera is given these hormones.
(5 marks)
FSH and LH are given to Meera before Egg collection. They are given to stimulate Egg Production so that more than 1 Egg can be collected.
True or False? Insulin causes Glucose to be released into the Blood.
(4 marks)
False. Insulin removes Glucose from the Blood.
Which Gland monitors and controls Blood Glucose concentration?
(1 mark)
The Pancreas
Explain why the body needs a constant internal environment.
7 marks
A constant internal environment is important because Cells need the right conditions in order to function properly (particularly for Enzyme Function). It can be dangerous for the body’s health if conditions vary too much from normal levels.
A person eats a Carbohydrate meal.
Their Blood Glucose levels raise after they have eaten.
How does their Blood Glucose levels reduce again?
(8 marks)
Insulin is secreted by the Pancreas. This causes Glucose levels to move from the Blood into the Cells of the Liver and Muscles, where it is stored as Glycogen.
Which Hormone increases the Blood Glucose levels?
5 marks
Glucagon acts to increase Glucose levels by converting Glycogen into Glucose, which is then released into the Blood.
Which Hormone lowers Blood Sugar levels?
1 mark
Insulin
How does Homeostasis affect Enzyme Action?
3 marks
Maintains optimal conditions (in the body), for Enzyme Action and all Cell Functions.
True or False? In Type 2 Diabetes, a person can become resistant to their own Insulin.
(3 marks)
True. The body cells no longer respond to Insulin.
Give 2 treatments for controlling Type 2 Diabetes.
3 marks
E.g. Eating a healthy diet, getting regular exercise, losing weight if needed.
What is Type 1 Diabetes? How is it treated?
9 marks
Type 1 Diabetes is where the Pancreas produces little to no Insulin. It is treated with Insulin therapy, where Insulin is injected into the Subcutaneous Tissue, from where it will enter the Bloodstream.
People with Type 1 Diabetes are also advised to exercise regularly and limit their intake of foods rich in Simple Carbs.
Calculate the BMI of someone who has a mass of 80kg and is 2m Tall.
BMI = Mass (kg) / (height (m))^2
(7 marks)
BMI = kg / m^2 BMI = 80 / 2^2 = 20
A woman has a waist and hip circumference of 100cm each.
Calculate her waist-to-hip ratio and explain whether she is at risk of Type 2 Diabetes.
(18 marks)
Waist-to-hip ratio = waist circumference (cm) / hip circumference (cm)
Waist-to-hip ratio = 100 / 100 = 1
This woman is at risk of Type 2 Diabetes. A ratio of above 0.85 for women is associated with an increased risk because it indicates that a lot of fat is being stored around the abdomen.
Which factors make Type 1 Diabetes different from Type 2: Type 1
(7 marks)
- Often diagnosed in childhood.
- Not associated with excess body weight
- Often associated with higher than normal ketone levels at diagnosis.
- Treated with insulin injections or insulin pump
- Cannot be controlled without taking insulin
Which factors make Type 2 Diabetes different from Type 1: Type 2
(7 marks)
- Usually diagnosed in over 30 year olds
- Often associated with excess body weight.
- Often associated with high blood pressure and/or cholesterol levels at diagnosis.
- Is usually treated initially without medication or with tablets.
- Sometimes possible to come off diabetes medication.
Give examples of differences between Type 1 and Type 2 Diabetes.
(7 marks)
Type 2: Usually diagnosed in over 30 year olds
Type 1: Often Diagnosed in childhood.
Type 2: Often associated with excess body weight, high blood pressure and/or cholesterol levels at diagnosis.
Type 1: Not associated with excess body weight but with higher than normal ketone levels at diagnosis.
List the differences between the treatment of Type 1 and Type 2 Diabetes.
(6 marks)
Type 1: Treated with insulin injections or insulin pump.
Type 2: Is usually treated initially without medication or with tablets.
Type 1: Cannot be controlled without taking insulin.
Type 2: Sometimes possible to come off diabetes medication.
What causes Type 1 Diabetes?
6 marks
Caused when the Pancreas fails to produce enough Insulin. This can be detected from an early age. It is characterised by uncontrolled High Blood Glucose Levels and it can be controlled by injecting Insulin.
What causes Type 2 Diabetes?
11 marks
Developed when the person’s body Cells no longer respond to Insulin produced by the Pancreas. It is more common in older people.
It can be controlled by a Carb controlled diet and an exercise regime. Carbs are digested into glucose, which raises the overall Blood Glucose level. There is a correlation between rising levels of obesity in the general population and increasing levels of T2D.
How does the size of an Organism affect its Surface Area to Volume ratio?
(3 marks)
The larger an Organism is, the smaller it’s Surface Area to Volume ratio.
Give 2 waist products that need to be removed from Cells.
2 marks
E.g. Carbon Dioxide and Urea.
Give 4 substances that Cells need to take in from the environment.
(4 marks)
E.g. Oxygen, water, dissolved food molecules and Mineral Ions.
Outline how Aerobic Respiration drives the need for the transport of gases in and out of Cells.
(4 marks)
Aerobic respiration requires Oxygen to be taken into Cells. Aerobic Respiration produces Carbon Dioxide that needs to be removed from the Cells.
Explain how Single-Celled Organisms can easily exchange substances with the environment, without the need for a transport system or an exchange surface.
(7 marks)
Single-Celled Organisms have a large Surface Area to Volume ratio. This means that enough gases and dissolved substances can diffuse directly into (or out of) the Cell to supply the needs of the Cell, so a transport system and an exchange surface are not needed.
A tiny elephant can be represented by a 3cm x 3cm x 3cm block.
Calculate the Surface Area to Volume ratio of the elephant.
(23 marks)
Surface Area = Length x Width of each side of the block = (3 x 3) x 6 = 54cm^2
Volume = Length x Width x Height = 3 x 3 x 3 = 27cm^3
So the Surface Area to Volume Ratio = 54 : 27 (can be Simplified to 2 : 1)
How can you calculate the Surface Area of an object?
4 marks
Surface Area = Length x Width of each side of the Object
How can you calculate the Volume of an Object?
6 marks
Volume = Length x Width x Height
How can you calculate the Surface Area to Volume ratio of something?
(17 marks)
Surface Area = Length x Width of each side (use cm^2 for blocks)
Volume = Length x Width x Height (use cm^3 for blocks)
Surface Area to Volume Ratio = SA : V
- Simplify when needed
What is the function of the Lungs?
4 marks
The Lungs transfer Oxygen to the Blood and remove waste Carbon Dioxide from it.
What are Alveoli?
4 marks
Alveoli are small air sacs in the Lungs where Gas Exchange takes place.
Explain why Alveoli need a good Blood Supply for efficient Gas Exchange.
(4 marks)
Alveoli need a good Blood Supply to maintain the Concentration Gradients of Oxygen and Carbon Dioxide.
Explain how Gas is exchanged between the Lungs and Blood that has just returned from the rest of the Body.
(13 marks)
The Alveoli are surrounded by Capillaries carrying Blood that has returned from the rest of the Body. The Blood contains lots of Carbon a Dioxide and not much Oxygen. In Alveoli, the Oxygen concentration is high and the Carbon Dioxide concentration is low. This means Oxygen diffuses out of the Alveoli into the Blood, and Carbon Dioxide diffuses out of the Blood into the Alveoli.
Some human groups that live at high altitude have larger Lungs than people who live at lower Altitudes.
Suggest how this could be an adaptation to high altitude, where there is less Oxygen available in the air.
(8 marks)
Having larger Lungs means that there is a larger Surface Area for Diffusion, so larger Lungs could be an adaption to help make sure that people who live at high altitude can get enough Oxygen into their Blood. This ensures that their Cells have enough Oxygen to maintain Aerobic Respiration.
Explain how the Adaptation of Alveoli’s (large) Surface Area allows for efficient Gas Exchange?
(14 marks)
Many alveoli are present in the Lungs with a shape that further increases surface area.
This allows for Gas Exchange to happen at a fast and more efficient rate. As more Oxygen (needed for Gas Exchange) can enter into the Alveoli, providing Oxygen to the Body’s Cells via diffusion. In the same way more Carbon Dioxide can diffuse out of the Cells into the Alveoli before being exhaled out.
Explain how the adaptation of the Alveoli’s thin walls are useful for Gas exchange.
(3 marks)
Alveolar walls are 1 cell thick providing gases with a short diffusion distance.
Explain how the adaptation of the Alveoli’s moist walls allow for efficient Gas Exchange.
(4 marks)
The Alveoli’s moist walls means gases dissolve in the moisture helping them to pass across the gas exchange surface.
Explain how the adaptation of permeable walls supports Gas Exchange in the Alveoli.
(2 marks)
Permeable walls allow gases to pass through easily.
Explain how the adaptation of an extensive blood supply supports Gas Exchange for the Alveoli.
(5 marks)
An extensive Blood supply ensures Oxygen Rich Blood is taken away from the Lungs and Carbon Dioxide rich blood is taken to the Lungs.
How is the large diffusion gradient adapted to help with gas exchange in the Alveoli?
(7 marks)
Breathing ensures that the Oxygen concentration in the Alveoli is higher than in the Capillaries so Oxygen moves from the Alveoli to the Blood. Carbon Dioxide diffuses in the opposite direction.
What adaptations are made to the Alveoli to make Gas Exchange more efficient?
(6 marks)
- Large Surface Area
- Thin, moist Permeable walls
- Good Blood supply
- Large Diffusion gradient
What other name can be used for Erythrocytes?
1 mark
Red Blood Cells
What is the function of White Blood Cells?
2 marks
WBC’s defend the body against infection.
What is Plasma?
2 marks
Plasma is the liquid that carries everything in Blood.
Describe the function of Lymphocytes.
6 marks
Lymphocytes are WBC’s that produce antibodies against Microorganisms. Some also produce antitoxins to neutralise any toxins produced by the Microorganisms.
Explain the importance of Haemoglobin in Red Blood Cells.
10 marks
Haemoglobin enables RBC’s to carry Oxygen through the body.
In the Lungs, Haemoglobin bonds to Oxygen to become Oxyhaemoglobin.
In Body Tissues, Oxyhaemoglobin splits up to release Oxygen to the Cells.
Besides the adaption of Haemoglobin in what other ways are Red Blood Cells adapted to their function?
(6 marks)
Red Blood Cells have a biconcave disc shape, which gives them a large Surface Area for absorbing Oxygen. They also have no Nucleus, which allows more room to carry Oxygen.
Some diseases can cause the number of Platelets in the Blood to fall to very low levels.
Why is it particularly dangerous if patients with these diseases start bleeding?
(5 marks)
Platelets help the Blood to clot at a wound, so patients with low numbers of platelets might not be able to stop bleeding because their Blood can’t clot properly.
What is another name for Platelets?
1 mark
Thrombocytes
What are the major types of blood cells in the human body?
6 marks
Red Blood Cells (erythrocytes)
White Blood Cells (leukocytes)
Platelets (thrombocytes)
How much of the Blood Tissue is taken up by Blood Cells (WBC’s, RBC’s and platelets)?
(7 marks)
A total 45% of the blood tissue by volume, is taken up by these 3 Blood Cells.
The remaining 55% of the volume composed of plasma, the liquid component of blood.
What is another name for White Blood Cells?
1 mark
Leukocytes
What is another name for Red Blood Cells?
1 mark
Erythrocytes
True or False? Arteries carry Blood to the Heart.
5 marks
False. Arteries carry the Blood away from the Heart. Veins carry Blood to the heart.
Which type of Blood Vessel has the largest Lumen?
1 mark
Veins
Which type of Vessel contains Valves? What is their function.
(3 marks)
Veins have Valves. They help to keep the Blood flowing in the right direction.
What is the advantage of the walls of Capillaries being only 1 Cell thick?
(6 marks)
It means the distance over which materials are exchanged is very small, so the rate of diffusion between Capillaries and Cells is high.
It takes 5 minutes for 1500ml of Blood to pass through an Artery.
Calculate the rate of Blood flow through the Artery in ml/min.
Use the equation: Rate of Blood flow = Volume of Blood / Time.
(6 marks)
Rate of Blood flow = Volume of Blood / Time
= 1500 / 5 = 300 ml/min.
Describe the difference in thickness between an Artery Wall and a Vein Wall.
Why does this difference exist?
(12 marks)
Arteries have thicker walls than veins. They carry Blood that has been pumped from the Heart at high pressure, so the walls have thicker layers of Muscle and Elastic Fibres to make them strong and elastic.
In Veins (which carry Blood back to the Heart), Blood is at a low pressure, so the walls don’t need to be as thick.
Capillaries branch out to form a network of Blood Vessels rather than continuing as a single Blood Vessel.
Suggest why.
(3 marks)
Capillaries branch out, allowing them to get close to every Cell in the body in order to exchange substances with them.
What are the main components of the Circulatory System?
3 marks
- Heart
- Blood
- Blood Vessels
What are the 2 main functions of the Circulatory System?
2 marks
- Transportation of substances
- Protection against disease
Explain the structure of the Red Blood Cell.
8 marks
Contain haemoglobin (rich in iron) to carry Oxygen. Biconcave shape to provide a large surface area for the diffusion of Oxygen. No Nucleus to provide more space for Haemoglobin.
Explain the structure of the White Blood Cell.
8 marks
Large cells that contain a nucleus. There are 2 types: Lymphocytes – make antibodies. Phagocytes – engulf and digest microorganisms.
What is the role of the Lymphocytes (type of WBC)?
Make antibodies.
What is the role of the Phagocytes (type of WBC)?
3 marks
Engulf and digest microorganisms.
Describe the structure of Platelets.
2 marks
Cell fragments (very small).
Describe Plasma.
2 marks
Straw coloured liquid.
What is the function of the Red Blood Cells?
1 mark
Carry Oxygen.
What is the function of the White Blood Cells?
2 marks
Defend the body against disease.
Describe the function of Platelets.
6 marks
Convert Fibrinogen to Fibrin. Fibrin forms a mesh that traps Blood. Important in Blood clotting and scab formation.
Describe the function of Plasma.
6 marks
Transports Blood Cells, digested food molecules (e.g. Glucose), Carbon Dioxide, Urea and Hormones.
Name the types of Blood Vessels.
3 marks
- Arteries
- Veins
- Capillaries
Describe the structure of Arteries.
9 marks
Thick walls with Muscle and Elastic Fibres to withstand high pressure. These features (of the walls) also allow the Artery to expand and recoil with each surge of Blood. The Lumen diameter is small and there are no Valves present in the Arteries.
Describe the Function of the Arteries.
4 marks
Carry Oxygenated Blood from the Heart to the rest of the body (Pulmonary Artery is the exception).
Describe the function of the Pulmonary Artery.
3 marks
Carries Deoxygenated Blood from the Heart to the Lungs.
Describe the structure of the Veins.
10 marks
The Lumen is large and reduces friction as the Blood moves through. Walls are thin and have very few Muscle and Elastic Fibres as Blood Pressure is low and does not surge through the Veins. Valves are present to prevent the backflow of blood.
Describe the function of the Veins.
4 marks
Carry Deoxygenated Blood from the body back to the Heart (the Pulmonary Vein is the exception).
What is the Function of the Pulmonary Vein?
3 marks
The Pulmonary Vein carries Oxygenated Blood from the Lungs to the Heart.
What is the function of the Capillaries?
8 marks
Allow the diffusion of substances (e.g. O2, CO2, dissolved food and Urea) between the Blood and the body’s Cells or vice versa.
Describe the structure of the Capillaries.
6 marks
Walls are 1 cell thick providing a thin, permeable surface for diffusion. They have a Small Lumen diameter. Blood moves through at a low pressure.
What is Lumen in the human body?
4 marks
Lumen (plural lumina) is the inside space of a tubular structure such as an Artery or a Vein.
Which side of the Heart pumps Deoxygenated Blood to the Lungs?
(1 mark)
Right side of the Heart.
Name the Blood Vessel which carries Blood into the Right Atrium of the Heart.
(1 mark)
Vena Cava
What is the Vena Cava?
5 marks
A large Vein that carries Blood to the Heart from other areas of the body. It is made up of 2 parts.
What are the 2 parts of the Vena Cava?
11 marks
Superior Vena Cava - carries Blood from the head, neck, arms, and chest.
Inferior Vena Cava - carries Blood from the legs, feet, and organs in the abdomen and pelvis.
What is the largest vein in the body?
1 mark
Vena Cava
What is meant by Cardiac Output?
3 marks
Cardiac output is the Total Volume of Blood pumped by a Ventricle every minute.
What is the function of the Valves in the Heart?
2 marks
Valves stop Blood from flowing backwards.
Describe the route that Blood from the Lungs takes through the Heart.
(7 marks)
Oxygenated Blood from the Lungs enters the Left Atrium through the Pulmonary Vein.
It then moves through to the Left Ventricle, and then leaves the Heart via the Aorta.
George is dissecting a sheep’s Heart.
What difference would allow him to differentiate the Right Ventricle from the Left Ventricle?
Explain the reason for this difference.
(8 marks)
E.g The thickness of the Ventricle Walls - the Left Ventricle will have thicker walls than the Right Ventricle. This is because the Left Ventricle has more Muscle so it can pump Blood around the whole body at high pressure, whereas the Right Ventricle only has to pump it to the Lungs.
A doctor tells Oskar that his heart rate is 60 beats per minute and his Cardiac Output is 4800cm^3 min^-1.
Calculate the Stroke Volume of Oskar’s Heart using the equation:
Cardiac Output = Heart Rate x Stroke Volume
(7 marks)
Stroke Volume = 4800 / 60 = 80cm^3