Term
| "What is vasoconstriction, and how does it keep you warm? |
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Definition
| When you are cold, the muscles in the walls of the blood vessels near the surface of the skin contract. Less blood flows near the surface of the skin, so less energy is lost to the enviroment. |
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Term
| What is vasodilation, and how does it cool you down? |
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Definition
| When you are warm, the blood vessels near the surface of the skin are filled with blood. Energy from the warm blood is transferred down the temperature gradient to the enviroment |
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Term
| Name the processing centre in vasoconstriction/vasodilation |
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Definition
| The hypothalamus sends nerve impulses to muscles in blood vessel walls to contract or relax |
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Term
| Name the effectors in vasocontriction/dilation |
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Definition
| The muscles in blood vessel walls constricting/relaxing |
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Term
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Definition
| The passive movement of molecules from areas where they are more concentrated to areas where they are less concentrated (dilute). |
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Term
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Definition
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Term
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Definition
| The diffusion of water across a partially permeable membrane. |
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Term
| What is active transport? |
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Definition
- Molecules are moved in or out of a cell using energy from respiration.
- This process is used when transport needs to be faster than diffusion, and when molecules are being moved from where they are at low concentration (dilute) to where they are at high concentration.
- Molecules can be moved in ONE DIRECTION ONLY, and AGAINST their DIFFUSION GRADIENT.
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Term
| Give 3 ways land animals lose water |
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Definition
| Sweating, panting, urination |
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Term
| Do seawater animals have a problem with water balance, why? |
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Definition
| No, the concentration of dissolved chemicals in their cells and body fluids is about the same as that of seawater. Water molecules enter and leave their bodies at the same rate. |
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Term
| Do freshwater animals have a problem with water balance, why? |
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Definition
| Yes, the concentration of dissolved chemicals in their bodies is much higher than in freshwater. Water constantly enters their bodies by osmosis. |
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Term
| How do freshwater animals, such as Paramecium, keep water balanced? |
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Definition
| They use energy to pump water out of their body. |
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Term
| What happens to land animals if they do not replace water all the time? |
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Definition
| Their body fluids become too concentrated and their cells do not work properly. |
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Term
| What keeps water levels in your body balanced? |
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Definition
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Term
| Give 3 ways you gain water |
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Definition
Water content in: food and drink Water made in: respiration |
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Term
| Give 4 ways you lose water |
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Definition
| Water content lost in: exhaled air, sweat, urine, faeces |
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Term
| On a hot day, or when you have been doing exercise, you lose a lot of water in sweat. What do tour kidneys do? |
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Definition
| They make a smaller volume of urine. Your urine will be more concentrated that day |
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Term
| What two jobs do your kidneys do? |
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Definition
| Water homeostasis (keeping water levels constant) and excretion |
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Term
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Definition
| Getting rid of waste products from chemical reactions in your cells |
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Term
| How are the two jobs your kidneys do related? |
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Definition
| Water is used to flush out waste products such as urea |
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Term
| How is urea made and dealt with? |
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Definition
| Liver cells make it when they break down amino acids your body cannot use. Urea diffuses into your blood and is carried around your body. |
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Term
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Definition
| Except in very low concentrations, it is poisonous. So as blood passes through your kidneys, urea is filtered out. |
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Term
| How do your kidneys work? |
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Definition
| They work like sieves. Smalls molecules are filtered out of the blood as it passes through your kidneys. These small molecules are water, sugar (glucose) and urea and ions of salt. Blood cells and large molecules, such as proteins, are too big, so they stay in the blood |
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Term
| Some of the small molecules that your kidneys filter out are useful to your body. You do not want to lose them. So the kidneys reabsorb what the body needs. What useful chemicals go back into the blood? |
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Definition
| All of the sugar (glucose) for respiration, as much salt as the body needs and as much water as the body needs. |
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Term
| What chemicals make up urine? |
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Definition
| All the chemicals that are filtered out by the kidneys and that aren't reabsorbed by them. |
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Term
| The salt concentration of your blood determines what? |
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Definition
| How much water your kidneys reabsorb |
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Term
| List 3 things that can cause the salt concentration of your blood to become higher than normal |
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Definition
| Excess sweating, not drinking enough water, eating salty foods |
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Term
| What does caffine cause to be produced? |
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Definition
| A greater volume of dilute urine |
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Term
| What does alcohol cause to be produced? |
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Definition
| A very great volume of dilute urine to be produced. Alcohol can make people very dehydrated. |
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Term
| The control system for water balance is a ……….. ……….... system |
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Definition
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Term
| Name the receptor in the negative feedback system for water balance |
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Definition
| Receptors in the hypothalamus in your brain detect any changes in salt concentration in the blood |
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Term
| Name the processing centre in the negative feedback system for water balance |
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Definition
| The hypothalamus - if salt concentration is too high, then it triggers the release of a hormone called ADH from the pituitary gland (also in the brain, just under the hypothalamus). If salt concentration is low, no ADH is released |
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Term
| Name the effector in the negative feedback system for water balance |
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Definition
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Term
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Definition
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Term
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Definition
| Causes the walls of the kidney tubules to become more permeable to water, so more water is reabsorbed. |
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Term
| How do caffine, alcohol and ecstasy affect ADH? |
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Definition
| Alcohol and caffine: suppress ADH production, ecstasy: stimulates ADH production |
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Term
| What does ecstasy do to the volume of urine a person produces? |
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Definition
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Term
| What can dry air in aeroplanes cause? |
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Definition
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Term
| When does heat stroke occur (give an example)? |
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Definition
When your body cannot lose heat fast enough, e.g. in humid conditions, you sweat, but the sweat cannot evaporate. It may be that you become dehydrated and produce too little sweat. Other examples: fever, prolonged exercise, over-exposure to the sun and drugs such as Ecstasy |
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Term
| List 3 symptoms of heat stroke and their causes |
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Definition
Symptom: hot dry skin, cause: sweating stops. Symptom: rapid pulse rate, cause: dehydration, stress, increased metabolic rate. Symptom: dizziness and confusion, cause: nerve cell damage in the brain |
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Term
| Rapid cooling of a patient with heat stroke is essential. List 5 treatments for heatstroke |
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Definition
Sponging them with water, wrapping them in wet towels, use a fan, putting ice in their armpits and groin, doctors may use cooled intravenous drips |
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Term
| When does hypothermia occur? |
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Definition
| When your core body temperature falls below 35 C. It can happen to anyone exposed to low temperatures for long enough. A person's body heat cannot be replaced as fast as it can be lost. |
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Term
| Who are most vulnerable to hypothermmia? |
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Definition
| Babies and the elderly - their temperature control systems work least well |
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Term
| Why are babies at greater risk of getting hypothermia? |
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Definition
| Because they have a large surface area compared with their volume, so they lose heat particularly quickly |
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Term
| How many deaths in the UK a year does hypothermia cause? |
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Definition
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Term
| Increasing the core temperature of a patient with hypothermia is essential. What SHOULD you do? |
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Definition
Insulate them (particularly the head, neck, armpits and groin), handle them gently to keep blood flow to the limbs low, warm them gently with warm towels, give them warm drinks |
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Term
| What should you not do to a patient with hypothermia? |
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Definition
Give them alcohol, give them food (digesting food lowers metabolic rate), use hot water bottles |
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Term
| Why is it important not to heat the skin and limbs of a patient with hypothermia? |
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Definition
| Because this increases blood flow to the skin and limbs. Heat loss then increases, and core temperature falls even further. This sudden cooling increases the risk of heart failure. |
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Term
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Definition
| Keeping conditions within the body constant. |
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Term
What must your body keep constant?
(5 facts) |
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Definition
| 1.)Body temperature 2.)salt and water levels 3.)nutrient levels 4.)oxygen levels 5.)waste product levels/get rid of |
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Term
| All control systems have... |
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Definition
A receptor
A processing centre
An effector |
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Term
| What does a processing centre do? |
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Definition
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Term
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Definition
| Detects stimuli (the change) |
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Term
| What does an effector do? |
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Definition
| Produces an automatic response |
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Term
| How does an incubator work? |
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Definition
| It is a control system. The temperature is detected by a sensor (the receptor). If the temperature falls below the normal, the thermostat (processing centre) switches on a heater (effector). If the temp. rises above the normal, the thermostat turns off the heater. |
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Term
| Name two ways you control your temperature |
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Definition
Automatically (e.g. sweating) Consciously (e.g. putting on a coat) |
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Term
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Definition
| When a change in a system results in an action that will reverse the change, bringing the system back to its normal state. |
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Term
| Explain negative feedback in an incubator to control temperature. |
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Definition
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Term
| Give one example of a negative feedback system |
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Definition
| The fridge - if the temperature inside goes too high, a motor is switched on to cool it. If it goes too low, the motor switches off. |
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Term
| Define antagonistic effectors |
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Definition
| Effectors that have opposite effects. |
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Term
| Describe a control system with antagonistic effectors. |
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Definition
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Term
| Give an example of where you would find antagonistic effectors |
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Definition
| In a car - accelerator and brake |
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Term
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Definition
They are catalysts that speed up the chemical reactions in living organisms. |
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Term
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Definition
| They are proteins - large molecules made up of long chains of amino acids. |
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Term
| Is the enzyme's shape important to how it works? |
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Definition
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Term
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Definition
| Some break down large molecules into smaller ones. Others join small molecules together. |
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Term
| Describe the lock-and-key model |
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Definition
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Term
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Definition
| At 37oC, chemical reactions in your body would happen too slowly to keep you alive. |
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Term
| One way of speeding up a reaction is to increase the temperature. As the temperature increases, the molecules... |
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Definition
have more energy move around faster and collide more often react more easily when they do collide |
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Term
| Why use enzymes and not increase body temperature? |
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Definition
Higher temperatures damage human cells To increase the temperature, you would have to release more energy from respiration, meaning more food to fuel respiration. |
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Term
Define optimum temperature for enzymes |
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Definition
| The temperature at which an enzyme works best. It's too low to denature the enzyme, but high enough for collisions between the enzyme and other molecules to be "frequent and energetic" |
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Term
| What happens to enzymes when they are above their optimum temperature? |
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Definition
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Term
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Definition
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Term
| What is the optimum temperature for enzymes in humans? |
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Definition
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Term
| Are enzymes denatured at temperatures lower than their optimum temperature? |
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Definition
| No. When the temperature increases, the rate of reaction will increase too. |
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Term
| Explain how an enzyme reaction can be stopped by a rise in temperature. |
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Definition
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Term
| Apart from temperature, what else affects the shape of an enzyme's active site? |
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Definition
pH levels - every enzyme has an optimum pH at which it works best. |
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Term
Name something that the body does that causes it to gain heat. |
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Definition
Respiration Glucose + oxygen ===> CO2 + H2O + ENERGY |
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Term
| Not all of your body is at the same temperature. Your a........... (b..... and c.....) are cooler than your d...... (e...... .....). |
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Definition
a extremities b hands c feet d core e deeper parts |
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Term
| Your body loses temperature a..... the b............... .................. This means that the greater the temperature difference, the greater the rate of c.............. |
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Definition
a down b temperature gradient c cooling |
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Term
What should body temperature be between? |
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Definition
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Term
What temperatures cause the following: death central nervous system breakdown fever hypothermia loss of consciensness loss of body temperature control muscle failure |
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Definition
44oC 42oC 37.5oC 35oC 33oC 30oC 28oC |
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Term
| Where in your body is the amount of energy released by respiration and other reactions greatest? |
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Definition
| In your muscles and your liver |
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Term
Where in your body would you find temperature receptors? |
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Definition
In your skin (detects air temperature) and in your brain (detects blood temperature) |
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Term
| Where in your body would you find the temperature processing centre? |
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Definition
| In your brain - the hypothalamus |
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Term
| What is the hypothalamus? |
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Definition
| The processing centre for sleep, water, balance, body temperature, appetite and other functions |
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Term
| What do the cerebral hemispheres do ? |
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Definition
Make conscious decisions to warm or cool yourself, e.g. taking off a coat |
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Term
| How does shivering warm you up? |
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Definition
| It makes the muscles contract quickly, meaning they must respire faster to release the energy for this movement. |
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Term
When you are too hot, a...... ......... from the brain stimulate your b........ ........ |
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Definition
a nerve impulses b sweat glands |
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Term
| Describe what happens when your sweat glands are stimulated. |
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Definition
| They make sweat, which passes out of small pores onto the skin surface. When the sweat exaporates from your skin, it cools you down. |
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Term
| How does sweat cool you down? |
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Definition
| Water molecules in sweat gain energy from your skin. Soon they move quickly enough to evaporate. This cools you down. |
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Term
| What happens when you sweat in hot, humid climates? |
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Definition
| It doesn't cool you down because it can't evaporate quickly. |
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Term
| Name two effectors for controlling body temperature. |
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Definition
| Muscles (shiver) and sweat glands (sweat) |
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Term
| Is your body temperature the same all day? (Give details) |
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Definition
| No - during exercise and after eating it rises, during sleep it lowers. |
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Term
| Name 5 ways your body warms you up. |
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Definition
Sitting Warm Can Heat Valerie Shivering Warm foods and drinks Clothes and hair raising Heater Vasoconstriction |
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Term
| Name 5 ways your body cools you down. |
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Definition
Sweet Children Prefer Fanning Valerie Sweating Cold food or drinks Protective clothing Fan Vasodilation |
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