Flashcards in Organisation And The Digestive System Deck (174):
The breaking down of large food molecules into smaller water soluble molecules both chemically and physically, occurring in certain organs e.g the pancreas
Why is digestion important?
Large insoluble food molecules cannot get into the blood which need to be used by our cells for vital processes e.g respiration and proteinsynthesis
What is the alimentary canal?
A muscular tube running through the body fork the mouth to anus
What is the function of bile? (3 points)
Breaks down large globules of fat into smaller ones (emulsifies them), increases the surface area of fat droplets, neutralises hydrochloric acid from the stomach as it’s alkaline
What concentration of oxygen does blood going into the stomach have?
What concentration of oxygen do cells lining the stomach have?
By which process does oxygen move from the blood to the cells lining the stomach?
What other substance moves from the blood to the cells lining the stomach so that respiration can take place?
In which part of a cell does aerobic respiration take place?
How many alveoli does a human lung have?
About 80 million
Give three features of the alveoli which allow large amount of oxygen to enter the blood
Large surface area, lots of capillaries, thin walls
Name the process by which oxygen passes from the air into the blood
How does breathing allow large amounts of oxygen to enter the blood?
More oxygen enters the alveoli and carbon dioxide passes out into the air, the alveoli maintains a higher concentration of oxygen
How are the villi adapted to maximise the rate of absorption of the products of digestion? (3 ways)
Lots of microvilli provides a large surface area, lots of capillaries meaning they maintain concentration gradient, they have lots of mitochondria which allows for respiration and energy release
Function of the small intestine?
digestion of fat
Function of the large intestine?
absorption of water into the blood
Function of the stomach?
Production of hydrochloric acid
How does the glucose concentration in the blood compare to that of the small intestine?
The concentration in the blood is lower
Which three organs produce amylase?
Salivary glands, pancreas, small intestine
Which two organs produce lipase?
Pancreas, small intestine
Which two organs produce protease?
How does acid help digestion?
This is the optimum pH for the enzymes
Amylase breaks down starch into...
Lipase breaks down fats into...
Fatty acids and glycerol
Protease breaks down proteins into...
Where is bile produced and released into?
Produced in the liver, released into the small intestine
Optimum pH of amylase?
optimum pH of protease?
Optimum pH of lipase?
Function of the rectum?
Function of the salivary glands?
Produces saliva containing the enzyme amylase
Function of the mouth?
What is the oesophagus?
A tube connecting the mouth to the stomach
Function of the anus?
Faeces leaves the body here
Function of the pancreas?
Produce enzymes and release them into the small intestine
Function of the gall bladder?
Function of the liver?
Oxygen moves from the lungs into the blood through the walls of what?
Two adaptions of the lungs that help rapid absorption of oxygen into the blood?
Large surface area, thin membrane
How do you test for sugar and what colour change will occur if sugar is present?
Benedicts reagent, green to orange to brick red
How do you test for starch and what colour change will occur?
Iodine, Brown to blue black
What is the function of enzymes?
Break down large insoluble food molecules into small soluble ones so they can diffuse into our cells
What are enzymes?
Biological catalysts, they are made of protein
The sum of all reactions in a cell or in the body
Why are digestive enzymes different?
Work outside of your cells, are released from specialised cells in glands and the lining of the gut, secreted onto the food travelling through the digestive system
What happens in an enzyme reaction if the temperature/pH is too high/strong?
The active site becomes denatured therefore the are less collisions so the reaction decreases and stops
How do we test for fat and what colour change occurs?
Reagent is filter paper, turns clear
How do we test for protein and what colour change occurs?
Reagent is Biuret, turns slightly pink
Why do enzymes have an optimum temperature?
They work best at this temperature and enzyme-substrate complexes form more quickly
Function of the heart?
To pump blood around the body
In which direction does an artery pump blood?
Away from the heart
In what direction does a vein pump blood?
Into the heart
Function of the veins?
To carry blood from the capillaries back to the heart and lungs
Function of skeletal muscles?
To push the blood up the body and back to heart
Is the blood carried by the veins oxygenated or deoxygenated?
Function of the arteries?
Carry blood away from the heart and to body cells
What pressure do veins carry blood under?
What pressure do arteries carry blood under?
What is the lumen lined with?
Is the blood carried by the arteries oxygenated or deoxygenated?
Function of the capillaries?
Carry blood away from the body and exchange nutrients, waste and oxygen with tissues at the cellular level
What do the capillaries’ tiny blood vessels do?
Is the blood carried by the capillaries oxygenated or deoxygenated?
What are platelets?
Cell fragments essential to blood clotting
Function of white blood cells?
Protect the body against disease
Function of the red blood cells?
Transport oxygen and have no nucleus to make more room
What is cardiac output?
The amount of blood the heart pumps in a minute
What is heart rate?
How often the heart beats
What is stroke volume?
How much blood is pumped out of the heart with each beat
What is the relationship between those three things?
CO = HR x SV
Four features of a good exchange surface?
Thin walls, good ventilation, lots of capillaries, large surface area
What is ventilation?
The process of inspiration and expiration
What happens during inspiration?(7 parts)
Ribs pull up and out, volume in chest increases, diaphragm contracts, further volume increase inside the chest, lower pressure in chest (less than atmospheric pressure), air drawn into the lungs from outside, lungs deflate
What happens during expiration? (6 parts)
Ribs pulled down and in, volume in thorax decreases, decrease in chest volume, pressure greater than atmospheric pressure, air forged out of lungs, lungs deflate
What is the relationship between pressure and volume?
Low pressure = high volume
What is health?
A state of physical and mental well-being
What is a risk factor?
Any factor, attribute, characteristic that increases the risk of developing a disease
What is a correlation?
A change in one variable is reflected by a change in another variable
What is cancer?
A group of diseases involving cells in a specific part of the body growing and reproducing uncontrollably
How does a tumour form?
Sometimes damaged cells pass through checkpoints which allows them to divide
4 characteristics of a benign tumour?
Not cancerous, cannot spread, inside a membrane, cause damage to other organs
6 characteristics of a malignant tumour?
Cancerous, can spread, can invade healthy tissue, cells can travel in the blood or lymph system, can form secondary tumours in other organs, destroys organs
What is the name for cell division?
4 risk factors of lung cancer?
Smoking, lack of exercise, unhealthy diet, air pollution
Risk factor of skin cancer?
Exposure to UV radiation
4 risk factors of cervical cancer?
Obesity, multiple pregnancies, smoking, STIs
3 risk factors of breast cancer?
Inherited genes, lack of exercise, unhealthy diet
4 risk factors of testicular cancer?
Smoking, unsafe sex, STIs, infertility
4 risk factors of brain tumours?
Radiation, smoking, drinking, being overweight
What is coronary heart disease?
Narrows the arteries which reduces the amount of blood travelling through them and reduces the amount of it reaching the heart so heart cells die
What happens with a faulty heart valve?
Pressure cannot build up in the chambers, heart must work harder to build up enough pressure, blood may back flow or clot
What do statins do?
Reduce cholesterol and build up of fat
What do stents do?
Allow blood to flow mor freely by holding coronary arteries open
What is a communicable disease?
An infectious disease transmissible by direct or indirect contact with an affected individual or their discharges
What is a non communicable disease?
A disease which is non infectious and non transmissible among people
6 ways disease is spread?
Water&food, animals, insects, bodily fluids, the aid, direct contact
8 ways to decrease your risk of disease?
Get vaccinated, wash hands often, use antibiotics safely, disinfect hot zones in your residence, don’t share personal items, travel wisely, safe sex, be smart about food prep
What is phagocytosis?
The process by which a cell (often a phagocyte or protist) engulfs a solid particle to form an internal compartment (a phagosome)
What is a phagocyte?
A type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles
What is a lymphocyte?
A small white blood cell which plays a large role in defending the body against disease
How do white blood cells recognise pathogens?
Pathogens have antigens (protein markers) on them
How do white blood cells break down pathogens?
White blood cells make antibodies of a specific shape to fit antigens perfectly which bind together and the pathogen gets broken down
What is an independent variable?
The variable you change
What is a dependent variable?
The factor you measure
What is a control variable?
The variable you keep the same
What happens to the body’s antibody concentration after the second infection and why?
The number of antibodies is greater because they are created quicker after being recognised
Why do communicable diseases spread faster after a natural disaster? (4 ways)
Disease can spread through water as a result of flooding, air becomes contaminated with gases, people are within close proximity of eachother in hospital, pathogens enter the body through cuts and wounds
Which are smaller viruses or bacteria?
What is the viruses DNA like?
Small section of genetic material in a protein coat
How do viruses infect the body? (6 steps)
The virus has antigens of a specific shape to fit the receptors of a host cell which allows is to enter, virus releases its DNA in order for replication to occur, the virus takes over the host cells organelle, the virus makes hundreds of thousands of copies, the virus copies fill the cell and burst it open, viruses enter the blood and may attach to a new cell
How is tobacco mosaic virus spread? (3 ways)
Plant wounds, tobacco on hands, contaminated seeds
What are three symptoms of tobacco mosaic virus?
Mosaic pattern on leaves, stunted growth, areas of leaf die
How is measles spread? (2 ways)
Inflation or droplets from coughs and sneezes, contact with infected individuals
What are 5 symptoms of measles?
High fever, runny nose, cough, red watery eyes, white spots on cheeks
How is HIV spread? (3 ways)
Bodily fluids, breast milk, placenta
What are 3 symptoms of HIV?
Rash, joint pain, swollen glands
How do bacteria multiply?
By binary fission
How frequently can binary fission occur?
Every 20 mins
What does bacteria need for binary fission?
Correct temperature and nutrients
What temperature are bacteria kept at in school labs to control their growth?
25 degrees Celsius
Is bacterial replication sexual or asexual reproduction?
Asexual because it requires one parent to produce identical copies
How do bacteria make us ill? (4 ways)
Release poisons or toxins, bodies provide favourable conditions for bacteria, they multiply rapidly, damage our tissues
What are 3 differences between viruses and bacteria?
Viruses are much smaller than bacteria, viruses contain DNA in a protein coat whereas bacteria have free flowing DNA, viruses need a living cell to invade unlike bacteria
What is gonorrhoea?
A sexually transmitted disease caused by a bacterium called Neisseria gonorrhoeac or gonoccus
How is gonorrhoea spread? (2 ways)
By sexual contact, can be passed from a pregnant women to a newborn baby
What 5 areas does gonorrhoea cause harm to?
Cervix, urethra, rectum, throat, eyes
What are three typical symptoms of gonorrhoea?
Green or yellow discharge from the vagina or penis, pain when urinating, bleeding between periods
How many infected men and women don’t experience symptoms of gonorrhoea?
1 in 10 men and almost half of infected women
How can gonorrhoea be treated?
Used to be treated with penicillin but now some strains of bacteria are resistant so it is now treated with a different single antibiotic injection and tablet
How can STIs be prevented?
Using appropriate contraception and condoms
Why is HIV so dangerous when it infects a pregnant women?
It can cause permanent blindness to a newborn baby
What does rose black spot disease do?
Causes holes and black pigmentation to form on the leaves of a plant
Why does rose black spot disease stunt plant growth?
Plants cannot absorb light through chlorophyll to carry out photosynthesis, plants need sugar to grow
How does rose black spot disease spread?
Through wind and water
How can rose black spot be treated? (2 ways)
Fungicides, remove the diseases area
What four places do fungi live in?
Water, air, plants, soil
What is a protist?
A single celled organism that grows on and contaminates food, they can be parasites
What is a parasite?
Lives on or inside another organism, relies on host for survival and causes it harm
What is malaria?
A serious tropical disease caused by a type of parasite called Plasmodium, passed person to person by an insect vector (mosquito)
What is a vector?
Something which spreads disease rather than causing it
When do malaria symptoms appear?
Between 7 and 18 days after becoming infected
What are 6 symptoms of malaria?
Sweats and chills, high temp, headaches, vomiting, muscle pains and diarrhoea
What happens after you are bitten by a mosquito infected with the parasite?
The parasite enters the bloodstream and travels to the liver where the infection develops before invading red blood cells
What two things do vaccinations do?
Help your immune system and protect you from disease like measles
How were vaccines discovered?
Edward Jenner recognised that milkmaids and shepherdesses did not have smallpox scars which meant they were immune to the disease however they had all had cowpox which meant that infecting an individual with cowpox prevents them catching smallpox
What is a vaccine?
A dead or inactive form of a pathogen, a prevention strategy
What are three arguments for vaccines?
Save peoples lives, plants do not need to be used in medicines, vaccines provide economic benefits for society
What are three arguments against vaccines?
Sometimes cause fatal side effects, tested on animals, are expensive
What happens in pre-inoculation of preparing an uncontaminated culture of bacterium in a Petri dish? (2 steps)
Petri dish and agar sterilised before use to kill unwanted bacteria, inoculating loop passes through flame/sterile swab to kill/sterilise other bacteria
What happens during inoculation of preparing an uncontaminated culture of bacterium in a Petri dish? (2 steps)
loop/swab used to spread bacterium onto agar, lid of Petri dish opened as little as possible to prevent microbes from the air entering
What happens in post-inoculation of preparing an uncontaminated culture of bacterium in a Petri dish? (2 steps)
Sealed with tape to prevent microbes from air entering, incubate to allow growth of bacteria
What is a medicine?
A chemical substance used in the diagnosis, cure, treatment or prevention of a disease
What do painkillers and antiseptics do?
Treat symptoms of a disease but do not kill pathogens
What are antibiotics used for?
Treating bacterial infections by preventing the cell wall forming or binary fission
Why do antibiotics not attack our own cells? (2 reasons)
We do not have cell walls and they may use specific enzymes
Why can’t antibiotics treat viral infections?
Viruses are inside of our cells so it’s difficult to develop drugs which kill viruses without damaging body tissues
How does bacteria become resistant to antibiotics?
Bacteria is killed by a specific antibiotic but one bacteria may have a mutation making it resistant, all mutated bacteria survive and reproduce rapidly so a large number of antibiotic resistant bacteria exist
What is a drug?
A substance taken into the body which modifies and affects chemical reactions in the body
What does aspirin originate from?
What does penicillin originate from?
How was penicillin discovered?
Some of Alexander Fleming ‘s bacteria samples had died after becoming contaminated with a particular fungus so he used this to treat bacteria infections in soldiers, he knew it worked because there were zones of inhibition
What was the problem with the discovery of penicillin?
Some strains of bacteria were resistant which resulted in MRSA
What six things need to be checked when developing a drug?
Effectiveness, toxicity, safety, ability to be taken in and out of the body, side effects, dosage
Why was thalidomide developed and what did it cause?
Developed as a sleeping pill but caused major defects such as shortened limbs
How long does drug development take and cost?
12 years, £600 million per drug
What happens in the research stage of developing drugs?
Researchers target a disease and make possible drugs using computer models
What happens in the pre clinic trials stage of drug development?
Drugs are tested on cells, tissues and sometimes whole organs but most are rejected
What happens in the pre clinical trials part two?
Involves animal testing which checks for side effects
What happens in the clinical trials of drug development?
Involves very few chemicals in the first human tests. Tested on healthy people as well as patients
What happens in clinical trials phase two?
Involves a small number of patients to check if the drug treats the disease
What happens in clinical trials phase three?
Involves a larger number of patients to check the dosage needed
What are three arguments for drug development?
Provides jobs, people have a right to be treated, cures many disease
What are three arguments against drug development?
Costs £600 million to develop a single drug, involves animal testing, can have side effects