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Learn about the 7 different food types and their impact on our bodies, the importance of exercise in weight management, the effects of cholesterol, the role of white blood cells in defending against pathogens, immunization and vaccines, the importance of good hygiene in preventing disease, and the use of antibiotics. Additionally, explore investigating microorganisms, the nervous system, and the role of hormones in the menstrual cycle and fertility.
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Diet A healthy diet contains the right balance of the 7 different food types
Carbohydrates Fat Protein 7 food types Water Fibre Vitamins Minerals
A Poor diet can lead to: • Obesity – being over weight • Being underweight • Diseases or conditions due to deficiency
Diabetes (high sugar levels) Arthritis (worn joints) Obesity High blood pressure Heart disease
Exercise • Exercise increases the amount of energy used by the body A person will lose weight when the amount of energy used by the body is more than the amount of energy in the food
Cholesterol is a substance • Made in the liver • Found in the blood The amount of cholesterol in your blood depends on: 1. Diet & 2. Inherited factors • Too much cholesterol can increase the risk of heart disease
Metabolic rate is The rate at which all the chemical reactions in your body’s cells are carried out Metabolic rate is affected by: • Amount of exercise you do • Proportion of fat to muscle • Inherited factors
Pathogens are... Micro-organisms that cause infectious disease
There are 2 pathogens that you need to know about & Bacteria Viruses
Why do bacteria and viruses make us feel ill? Producetoxins Reproducevery quickly
White blood cells • Ingest/digest pathogens • Produce antibodies • Produce antitoxins
How do white blood cells help defend against pathogens? White blood cell changes shape, engulfs and ingests the microbe White blood cells produce antitoxins which counteract the toxins released by the pathogens White blood cells produce anti bodies which destroy particular bacteria or viruses
Immunisation and vaccines Vaccines are used to protect us from diseases, making us immune (immunised) • Inject small amounts of inactive/dead pathogen into body • White blood cells produce specific antibodies to destroy the pathogen • If the pathogen re-enters the body, our white blood cells remember the specific antibody required to destroy it quickly
MMR MMR is an example of a vaccine used to protect children from: Measles Mumps Rubella
Preventing disease • Semmelweiss recognised the importance of good hygiene to prevent spreading of infectious diseases • He insisted doctors washed their hands before examining patients • This reduced the number of deaths from infectious diseases
Treating disease • Painkillers – relieve the symptoms of infectious disease (less pain) • Antibiotics - kill bacteria in the body • Antibiotics DO NOT kill viruses. Viruses live and reproduce inside cells.
Antibiotic resistance • Many strains of bacteria have developed a resistance to antibiotics (such as MRSA), as a results of natural selection • New antibiotics need to be developed all of the time. • It’s important not to overuse antibiotics
Uncontaminated cultures of microorganisms are required for investigating the action of disinfectants and antibiotics
Petri dishes must be sterilised before use Petri dishes containing agar are used by to grow cells (microbiology)
Inoculating loops are used to transfer microorganisms in the media Inoculating loops must be sterilised by passing them through a flame
The lid on the petri dish should be secured with adhesive tape... this is to prevent microorganisms from the air contaminating the culture
In school and college laboratories, cultures should be incubated at a maximum temperature of 25°C, which greatly reduces the growth of pathogens that might be harmful to humans
The nervous sytem The nervous system enables humans to react to their surroundings and coordinate their behaviour It consists of • The brain • The spinal cord • Neurones (nerves) and • Receptors
There are 3 types of neurones Sensory neurone Relay Neurone Motor Neurone
Synapse A synapse is a gap found between neurones
receptor What happens at a synapse? • Chemical neurotransmitters • Move across the gap by diffusion • Between neurones nerve impulse
Stimulus Receptor Sensory neurone Brain and spinal cord (CNS) Relay neurone Motor neurone Effector (muscle or gland) Response
Reflex action • Reflex actions are automatic and rapid responses. • They DO NOT involve the brain • They often involve sensory, relay and motor neurones
Hormones • Hormones are chemical messengers • There are produced by glands • They travel in the blood stream • They travel to target organs Gland Bloodstream Organ
There are 4 hormones you need to know about in the menstrual cycle: • Follicle stimulating hormone (FSH) • Oestrogen • Luteinising hormone (LH) • Progesterone
IVF is given to women who have difficulty getting pregnant: • Mother given FSH and LH to mature eggs • Eggs collected from mother • Eggs fertilised in a lab using father’s sperm • Fertilised eggs develop into embryos • One or two embryos are inserted into mother’s uterus/womb to develop
Plants are sensitive to light, moisture and gravity: Plant hormones
PhototropismPlant shoots grow towards light and against the force of gravity GravitropismPlant roots grow towards moisture and in the direction of the force of gravity
Control in plants • Auxins are hormones which cause growth responses in plants • Gardeners may use plant hormones as: weed killers and as rooting powders
Drugs are chemical substances that alter the way the body works Drugs
Types of drugs painkiller Paracetamol, Heroin, aspirin sedative Alcohol, sleeping tablets stimulant Caffeine antibiotic Penicillin antiseptic TCP (trichlorophenol)
Legal and illegal drugs • Recreational drugs – for leisure • Legal drugs eg, alcohol or tobacco • Illegal drugs eg, heroin, cocaine are very addictive
Developing drugs Drugs are tested and trialled in a series of stages to find out: • If they are toxic • If they are efficient (efficacy/do they work?) • What dose/strength is needed
Placebo = fake or dummy drug Double blind trial = neither doctor or patient knows who has received a placebo to reduce bias