B1 Understanding Ourselves

B1Understanding Ourselves

Revision LessonsDoes not contain all of the content for B1 – use checklists..\B1 Understanding Organisms\B1 Summary and Checklist\B1 Checklist FOUNDATION.doc..\B1 Understanding Organisms\B1 Summary and Checklist\B1 Checklist HIGHER.doc

The Circulatory system Heart muscle contracts to make the heart beat. This squeezes blood through blood vessels called __(1)____We need blood under pressure around the body because blood contains ___(2)___ and ___(3)___. These are needed so that all the __(4)__ in our bodies can produce ___(5)__ through ___(6)___. Blood is pumped at high pressure. Blood pressure is measured in mmHg (millimetres of __(7)__). Diastolic and systolic measurements are used. Normal pressure is about 120/80 mmHg. Words – energy, mercury, arteries, glucose, respiration, oxygen, cells

High Blood Pressure High blood pressure is a condition where the __(1)__ and blood vessels experience extra strain. It can be caused by: • Excess weight • High stress levels • __(2)__ • Excess ___(3)___ • Diets that are high in saturated __(4)__, sugar or salt Long term high blood pressure can cause blood vessels to weaken or even ___(5)___. Words – alcohol, burst, smoking, heart, fat

Now try these! • Nikki’s blood pressure is 150/90mmHg. Which number is the systolic measurement? • What does mmHg mean? • Her blood pressure is high. What are the dangers of high blood pressure? • What lifestyle changes can she make to reduce her blood pressure? • Answers • 150 • Millimetres of mercury • Blood vessel burst - Stroke, kidney, brain damage • better/low fat diet, regular exercise, not smoking, low or no alcohol intake, not overweight, reduce stress levels . Extreme cases = drugs

Heart Disease • 1. Smoking – increases BP - carbon monoxide-combines with haemoglobin reduces oxygen, heart rate increases - nicotine – stimulant – increases heart rate 2. Saturated fat – cholesterol builds up-forms a plaque-narrows artery 3. High salt levels – body retains too much water – higher volume of blood pumped Qu. Fatty deposits can build up on coronary arteries. Explain how this can lead to a heart attack Blood flow is restricted, heart muscle receives less oxygen. A thrombosis may occur blocking blood flow to areas of the heart restricting oxygen so it will die – heart attack.

Deep Vein Thrombosis (Higher) When we don’t move for a long time (e.g. on a plane journey), our leg muscles can’t squeeze the veins in our legs, so blood in the veins begins to move very slowly. A blood clot (thrombosis) may eventually form, blocking the vein and leading to Deep Vein Thrombosis (DVT). Flight socks can help prevent DVT by applying pressure to the legs, which helps squeeze blood through the veins. Leg exercises can also help to prevent DVT.

Measuring fitness - higher Flexibility: amount of joint movement Strength: amount of weight lifted Speed: ability to sprint Stamina: time of sustained exercise Agility: ability to change direction

Balanced diet A balanced diet should contain fats, proteins and carbohydrates in roughly these amounts: It should also contain water, vitamins, minerals and fibre.

Balanced diets Nutrient Function

Protein Meat and fish are “first class” proteins Proteins are long chains of amino acids. There are two main types of these: • Essential amino acids (must be eaten) • Non-essential amino acids (can be made in the body) People who do not eat enough protein will not grow properly. Protein deficiency can result in a disease called kwasiorkor, where the muscles waste away and the belly swells. How much protein should we eat? EAR of protein (in g) = 0.6 x body mass (in kg)

Food storage - higher • How are fats, carbohydrates and proteins stored in the body? • Carbohydrates stored in liver as glycogen or converted to fats • Fats stored under skin and around organs – adipose tissue • Proteins can’t be stored. First class proteins (meat, fish) contain all essential amino acids that can’t be made by the body. Second class proteins (plant proteins) don’t contain all essential amino acids

Body-Mass Index Mass (kg) Height2 (m2) BMI = A commonly-used way to indicate is someone is overweight or underweight is the Body Mass Index (BMI):

Try these • Elaine is 1.78m tall and has a mass of 66kg. Calculate her BMI. • Anthony is not overweight. Why could his BMI be so high? • What is EAR of protein and why is it important? • What does EAR depend on? (higher) • What can a balanced diet depend on? • 66/(1.78)2 • Doesn’t account for muscle mass • Estimated Average daily requirement of protein, eating too little protein – kwashiorkor • Age and pregnancy • Age, gender, physical activity, religious, personal, medical reasons

Eating disorders Anorexia nervosa – this is a condition where sufferers restrict what they eat and sometimes starve themselves, leading to possible weight loss, abdominal pains, discoloured skin, irregular periods etc. Bulimia nervosa – this is when people vomit or take laxatives straight after eating to get the food out as quickly as possible. It can lead to weight fluctuations, poor skin, hair loss, irregular periods, tiredness etc.

Now try this! • Link each food type to the correct product.

Fitness and Health • Joe catches a cold. He is surprised because he is very fit. • His coach explains that being fit does not stop bacteria and viruses entering his body and causing infections. Q. What is the difference between fitness and health? • Fitness is the ability to do physical activity. • Healthy is being free from disease.

Malaria

Now try this! • What is a pathogen? • Give 4 examples of pathogens • What is the best way to control malaria? 4) A mosquito is which of the following? • Parasite • Prey • Vector • A micro-organism that causes disease. • Fungi, bacteria, viruses, protozoa • Spray/drain stagnant water, Insecticides, mosquito nets • Vector

Microbes: our defence against them The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes Tears contain lysozyme, an enzyme that kills bacteria If our skin is cut platelets seal the wound by clotting The skin acts as a waterproof barrier Our blood contains white blood cells Our bodies have defence mechanisms against invading microbes:

Cleaning our air Our respiratory system has two types of specialised cell that help to keep our lungs clean: 1. Mucus is produced and traps dust, bacteria etc 2. The mucus is swept upwards to the mouth by cilia (cells with tiny hairs)

White blood cells If microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: • White blood cells do 3 things: • They eat the microbe (these white blood cells are called “phagocytes”) • They produce antibodies to neutralise the microbe (“lymphocytes”) • The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again)

Producing antibodies You’re going down Step 1: The lymphocyte “sees” the pathogen (microbe) Step 2: The cell produces antibodies to “fit” the pathogen Step 3: The antibodies fit onto the pathogens and cause them to “clump” Step 4: The pathogens are “eaten” by the white blood cells. Some memory cells stick around!

Specific antibodies Antibodies are specific – they will neutralise the microbe they have been made for.

Fighting disease Immunisation • Can be done in two ways: • A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called ACTIVE IMMUNISATION • The antibodies made by another organism are injected directly into the body – this is called PASSIVE IMMUNITY Name two differences between passive and active immunity. Active has a lasting effect but may take a few weeks to become effective

Vaccinations For Against MMR vaccine Some people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument:

Using Antibiotics Antibiotics can be used to kill bacteria. However, there are two problems: 1) Overuse of antibiotics can lead to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly. 2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course” or with the use of antivirals

Now try these! • Fill in the gaps! Antibodies are made by our ________. Antibodies lock onto ___________ on the surface of a _____________. Antibiotics do not kill pathogens such as ____________. A ________ is a harmless pill that can have a positive psychological effect. A ______ is where volunteers don’t know which treatment they’re receiving A________ is where the doctors don’t know either White blood cells, passive, blind trial, antigens, pathogen, double blind trial, active, viruses, placebo

The Nervous System The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. • Types of receptor: • Light receptors in the eyes • Sound receptors in the ears • Taste receptors on the tongue • Smell receptors in the nose • Touch, pressure and temperature receptors in the skin • Changes of position receptors in the ears (balance)

Conscious actions 4) The brain decides to move away the hand 3) Here another sensory neurone carries the signal to the brain 5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONES to the spinal chord 1) Receptors in your skin detect a stimulus 6) Which then moves the hand away Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response A conscious action is one where the brain makes a considered response. Here’s what happens:

Examples of reactions

Types of nerve cell Nucleus Muscle strands (effector) Cell body Dendrites Impulse Impulse Nerve cells (neurones) are elongated with branched endings to connect to many muscles fibres. 1) Motor neurone 2) Sensory neurone 3) Relay neurone

Synapses - higher Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse. These transmitters are then ________. Words – chemical, synapse, neurone, touch, destroyed

Reflex actions Sometimes conscious action is too slow to prevent harm, e.g… In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

Reflex actions 3. Relay neurone in the spinal chord 2. Sensory neurone 4. Motor neurone 1. Receptor 5. Effector

6 mark question - Higher The quality of written communication will be assessed in your answer to this question. Describe how neurones are adapted to carry and pass on nerve impulses quickly from one neurone to the next.

Level 3 Answer correctly applies knowledge of how and why neurones are adapted being long, having branched endings and insulated by a fatty sheath There should be reference to the synapse and how this allows impulses to travel in one direction (see diagram). All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how neurones are adapted and how the synapse is the gap between two neurones to allow nerve impulses to travel in one direction . For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple neurone and synapse description. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

6 marker question - Foundation The quality of written communication will be assessed in your answer to this question. Explain why active immunity is used for an outbreak of a disease over passive immunity.

Level 3 Answer correctly applies knowledge of active immunity to give a well-reasoned explanation of how dead or inactive pathogens are injected into the body and how they trigger your immune system to make their own antibodies and that this is usually permanent. There should be reference to passive immunity and how this is only temporary involving injecting antibodies directly. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of active and passive immunity to give a partial explanation of how immunity is different and why active is better in this case. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple immunity description, recognising that active immunity is different to passive immunity. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

Vision “Binocular vision” “Monocular vision”

The Eye Iris Sclera Lens Retina Pupil Optic nerve Optic nerve Cornea Suspensory ligaments Suspensory ligaments Ciliary muscles

Seeing things Rays of light are refracted (bent) first by the cornea and then by the lens. They focus on the retina.

Focussing on different distances For distant objects the ciliary muscles relax and the suspensory ligaments pull tight making the lens pull thin – the light doesn’t bend as much. When an eye focuses this is known as accomodation For close objects the ciliary muscles contract allowing the lens to go fat, thus bending the light more.

Correcting eye sight problems Long sighted people are unable to focus on ______ objects. The eyeball is too ________, so the image of near objects are brought into focus behind the retina. You can use glasses or contact lens with a ________ lens to correct it Short sighted people are unable to focus on _______ objects. The eyeball is too _________, so the image of distant objects are brought into focus in front of the retina. You can use glasses or contact lens with a _________ lens to correct it. Concave, convex, short, long, near, close

Drugs

Try these • 1. Which class of drug is the most dangerous, give some examples. • 2. Higher – Explain how the effects of alcohol are different from nicotine. • 3. Why do people get smokers cough? • Class A – heroin, LSD, ecstasy, cocaine • Nicotine is a stimulant so more neurotransmitter will cross to the next neurone, whereas alcohols a depressant so binds to receptors to block impulses/slow down • Smoke stops cilia from moving and makes goblet cells produce more mucus. Dust collects and irritates

Smoking • Cigarettes contain 3 harmful things: • NICOTINE, which is an ___________ drug that raises the heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________. • TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________. • CARBON MONOXIDE, which is a _______ ____ which joins up with ____ blood cells making them incapable of transporting _____________ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______. Words – high blood pressure, oxygen, red, addictive, disease, poisonous gas, lungs, cancer, mass

Homeostasis Homeostasis means “controlling internal conditions”: Produced by respiration, removed via lungs Produced by liver breaking down amino acids, removed by kidneys and transferred to bladder Increased by shivering, lost by sweating Increased by eating, lost by sweating + urine Increased by drinking, lost by sweating + urine Increased and decreased by hormones

Maintaining Body Temperature Vasodilation Cold Hot Vasoconstriction

6 marker -Foundation The quality of written communication will be assessed in your answer to this question. • It is important to keep the body temperature at 37oC as this is the optimum temperature for many enzymes. • Explain what would happen if a person gets too hot and how homeostasis helps us to cope with this.

B1 Understanding Ourselves