- Created by: Georgie
- Created on: 08-06-12 14:49
Microbes and diseases
-A pathogen is a disease causing micro-organisms.
Bacteria, Viruses, and Fungi.
General bacteria and general viruses have different looks.
-All viruses are Pathogens.
Definition of a pathogen-
-an infectious disease.
-Transmissions can be direct and indirect.
-Direct involves physical contact with people, mother to baby, or getting coughed or sneezed on.
-Indirect involves touching an object that has the pathogen on it, or being infected through another creature.
-May live as single cells
-Usually join to form threads
-Feeds on decaying plants and animals or on living cells
a single yeast cell is 0.005cm <----------->
-nazel hair + mucus= second line of defence
-lyzosome:-enzym in tears
-Each bacteria, virus gives off a chemical sent.
antigen- chemical sent
ANTI-BODIES take over and cling onto the viruses. Then the white blood cells take over.
Diet and energy
Your metabolic rate is a measure of how quickly your cells are converting food into energy.
-Men have faster M.R's than women-Young people have faster M.R's than older.
- The greater proportion of muscle to fat in the body, the higher the metabolic rate is likley to be.
A balenced diet:-
>carbohydrates for energy >fats for energy and making cell membranes >proteins for growth and repair and energy >vitamins and mineral ions for keeping healthy > roughage (fibre) to keep the digestive system going >water to transport other nutrients.
The amount of energy(food) you take in needs to be equal to the amount of energy you use.
-Cholesteral is often found in burgers, bacon, chips etc.
-It is produced by the liver and found in certain foods, and is needed to make cell membranes although too much is bad for you.
-It can form blockages in blood vessels and if the blockages restrict blood flow, this may lead to heart disease.
-Saturated fats can increase your cholesteral level where as unsaturated fats can be benefical to your heart. Unsaturated fats are found in plant oils, such as sunflower oil.
-If two people have to same diet but one has a higher blood cholesterol than the other, it can because one person does more excersise than the other. Exercise increases your metabolic rate and increases the use of energy from the food you eat, so less fat remains in the system meaning a lower blood cholesterol level.
Plaques and Diabetes.
LIKE METABOLIC RATES, CHOLESTERAL LEVELS CAN BE AFFECTED BY INHERITED FACTORS.
-high level of cholesterol in the blood increases the risk of developing plaques in the walls of the arteries.
Plaques can cause heart attacks by building up in the cell wall of the artery>slows down blood>clot forms>blocks aterie that takes ovygemated blood to heart muscles>heat attack because the muscle can't work so can't beat properly.
-you are more likley to get diabetes>close relitives
>if you don't have a healthy life style
-Made doctors wash their hands with Chloride of lime>made him unpopular
-Died of child bed fever
-Septaceamia-woman died from
-in 6 years death rate went from 10% to 3%
-No one new about bacteria and viruses then
-No one listened to him
-Died from septaceamia
White blood cells
- fight against pathogens in the body
- ingest pathogens and kill them
- make antibodies and antitoxins.
- are part of your immune system
Antibodies attach to antigens preventing them from attacking cells in the body. Antitoxins attack antigens and destroy them
LYMPHOCYTES ARE CELLS AND ANTIBODIES ARE MOLECULES.
Lymphocytes produce antibodies and antitoxines to attack pathogens.
Phagocytes kill bacterium by surrounding it in the cytoplasm, in a vacuole. It is then killed and digested by enzymes.
Pain and disease
Pain killers- Nurofen, Paracetomol, Morphone
Antibiotics kill bacteria and not viruses.
Bacteria can develop resistance to antibiotics, it happens by natural selection.
MRSA bacteria are most commonly found in hospitals, because patients have weak immune systems and weak defenses against disease.
Natural selection is where one bacterium is not effected by an antibiotic, and so rapidly divides and makes copies of itself that cannot be killed by antibiotics.
Small amounts of dead or inactive pathogens are injected into your body.
Antigens in vaccine stimulate white blood cells to make antibodies>antibodies destroy antigens without any risk of you getting the disease>you are immune to future infections by the pathogens.
Bacteria and fungi can be grown in a liquid or a jelly containing all the nutrients that they need. The jelly or liquid id called a nutrient medium.
A nutrient medium is a food source for bacteria. It must be sterile, sterilised means all the microorganisms on it have been killed.
Nerves and hormones
Your spine and brain make up your central nervous system.
Information travels from the eyes to the brain along nerves, as fast moving electrical impulses(signals)>the brain then sends impulses to the muscles.
>carry information between organs
>made by certain glands
Release process if called secretion
The bloodstream carries the hormones around the body.
>have different positions in the body
>detect stimuli and effectors respond to them
Examples of receptors are;vision,smell,touch,taste,hearing and balance.
Examples of stimuli are;light, touch, movement, temperature, pain, position and chemicals.
A Stimulus is a change in the environment.
Effectors do something in response to the stimulus.
The cells that transmit the impulses through the nervous system are called neurones.
There are two different types of neurones sensory neurones and motor neurones.
Reflex arc is the pathway taken by a nerve impulse as it passes from a receptor through the central nervous system, and finally to an effector.
Synapses, is the gap between the end of the neurone and the start of the next. The impulses, stop at the gap which causes a chemical to be diffused. It travels along to the beginning of the next neurone, and the electrical impulse continues.
Controlling the body hormones
Chemical signals travel around the body using the cirulatory system.
Testorone- male hormone
Adrenalin- fight or flight testorone makes your heart beat faster
insuline- controls your blood sugar
Progestrone --------FEMALE HORMONE
ADH-how much urine you produce
Glucagon- raises blood sugar levels.
SEX DRIVE-sex hormones are produced in the sex organs but this is controlled by the piturilory gland in the brain.
Hormones and Homeostasis
Endocrine system-hormone system
homeostasis-controls the body temporature
shivering creates friction
hair pricks up- traps air.
Insulin and Glucagon are produced in the pancreas.
Insulin-converts glucose into Glycogon
Glucagon-converts Glycogon into glucose.
The egg is made in the pituitary gland in the brain.
The start>the pituitary gland secretes FSH>Egg matures in overies>FSH stimulates the ovary to secrete oestrogen>lining of the uterus grows thicker>the lining grows extra blood vessels>prepares for the arrivel of fertilised egg>more oestrogen is secreted>high levels cause the pituitary gland to stop producing FSH> ovary to stops secreting oestrogen>this cuts off the inhibition of FSH secretion>so cyle starts all over again.
Control in plants
Tropisms- plants grow in particular directions. These responses are called tropisms.
Shoots- grow towards light and away from gravity
Roots- grow towards gravity and usually grow away from light.
Phototropism- a growth response to light.
Positive phototropism- when shoots grow towards the light
Negative phototropism- when roots grow away from the lgiht.
Gravitropism or geotropism- a growth response to gravity
Auxin- accumilates on the lower side of the root and reduces the rate of growth.
>change the body's chemical processes
>have side effects
>some drugs can cause dependency and addiction