Unit 1A - Human Biology Flashcards
What is needed for a balanced diet and why? (6)
Carbohydrates to release energy
Fats to keep warm and release energy
Protein for growth, cell repair and cell replacement
Fibre to keep everything moving smoothly through the digestive system
Vitamins and Minerals to keep skin, blood and bones healthy
Water
Why do you need energy?
To fuel chemical reactions in your body
Reactions called metabolism
Speed they occur at is your metabolic rate
What factors affect the amount of energy you need?
Muscle needs more energy than fat so people with a higher proportion of muscle have a higher metabolic rate
Bigger people need more energy
Men need more energy than woman
Genetics
Regular exercise means you have a higher metabolic rate
What is malnourishment ?
When your diet is badly out of balance, fat or thin
What leads to obesity?
Excess carbohydrates or fats
What health problems arise from too much food?
Arthritis Type 2 diabetes High blood pressure Heart disease Cancer Obesity
Too much saturated fat or salt leads to what?
High blood cholesterol levels
High blood pressure and heart problems
What does eating too little lead to?
Slow growth in children
Fatigue
Weak immunity system
Irregular periods in women
What are deficiency diseases?
Lack of vitamins or minerals
Eg scurvy, lack of vitamin C
What are the two main types of pathogen?
Bacteria
Viruses
What are bacteria and what do they do?
Very small cells (micro organisms) that reproduce rapidly
They make you feel ill by damaging your cells and producing toxins
What are viruses?
They are smaller than cells
They invade your cells and use them to reproduce
You feel ill when your cells burst releasing all the new viruses
How does your body keep stuff getting into your body?
Skin
Hairs and mucus in respiratory tract
Platelets help blood clot fast to seal wounds to stop pathogens entering through cuts
How does the immune system work?
White blood cells can engulf foreign cells and digest them
White blood cells produce proteins called antibodies that are specific to the pathogens antigen to kill it
Will reproduce rapidly if invaded again because of memory cells
Antitoxins produced to counteract toxins produced
How does a vaccination work?
Inject small amounts of dead or inactive pathogens
White blood cells produce antibodies to counter the antitoxins
If live pathogens enter the body the antibodies can rapidly reproduce to counteract the antigens because of memory cells
Some vaccinations wear off over time so booster injections given to increase antibody levels
What are the pros and cons of vaccinations?
Helped control many infectious diseases that were once common eg. MMR, smallpox no longer exists
Epidemics can be prevented as people who are vaccinated won’t get the disease and even those whose aren’t are less likely as there are less people to catch it from
Don’t always work
Sometimes bad side effects but very rare eg. Swelling, seizure or fever
What do different types of drugs do to pathogens?
Painkillers relieve you from the symptoms but don’t kill the pathogen
Antibiotics actually kill or prevent the growth of bacteria specific antibiotics needed for specific bacteria
They don’t work on viruses because they develop inside your cells so difficult to kill them without killing the bodies cells
How do bacteria become resistant to antibiotics?
Some can mutate to become resistant
This means when you use antibiotics they will survive
They will reproduce and the percentage of the population that are resistant increases due to natural selection
Resistant strain could lead to serious infection because of no cure
eg. MRSA
To slow down their development antibiotics shouldn’t be over prescribed and when are you need to finish the course completely
How do you investigate the effectiveness of antibiotics on bacteria?
Bacteria are grown in a cultured medium (agar jelly) provides them with all the nutrients needed
Agar jelly is put in a Petrie dish and the bacteria is transferred onto it using inoculating loops
Paper discs soaked in antibiotics, non resistant bacteria die
All the equipment is sterilised prior to the experiment and a lid is placed on the Petri dish
At school 25 degrees used to stop harmful pathogens growing
In industrial conditions higher temperatures used to make them grow faster
Who was Semmelweis?
Worked in Vienna general hospital in the 1840s
Saw a large number of women were dying after childbirth
Made doctors use antiseptic solution before entering his ward
Cut deaths from 12% to 2%
No one knew about bacteria at the time so couldn’t prove why it worked so the idea was dropped when he left the hospital increasing the number of deaths again
What are the dangers of a new strain of bacteria or virus?
Could be antibiotic resistant
Could be a new strain that no one has encountered so no one is immune
This would lead to an epidemic as the new strain would spread rapidly
Viruses mutate often so hard to develop vaccines against them because their antigens are always changing
If the virus becomes very infectious and deadly this could lead to a pandemic
What do sense organs detect?
Stimuli, a change in your environment
What are the five sense organs, what receptors do they have and what are the stimuli they detect?
Eyes, light receptors, sensitive to light
Ears, sound and balance receptors, sensitive to sound and changes in position
Nose, smell receptors, sensitive to chemical stimuli
Tongue, taste receptors, sensitive to chemical stimuli
Skin, sensitive to touch, pressure, pain and temperature
What is the CNS
The central nervous system
Where all the information from the sense organs is sent
Coordinates reflexes and actions
Consists of brain and spinal cord
Neurones used to transmit information
Instructions from CNS sent to the effectors (muscles or glands)
