F222 revision human biology

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  • Created by: Hannah
  • Created on: 04-01-13 12:08

Suggest two reasons why the risk of cancer increas

- more mutations

-immune system declines with age

- longer exsposure to carcinogens

-mutated cells not detected/destroyed

-DNA proof reading is not efficient

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explain ways of detecting breast cancer?

PET scans

MRI scans




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2 ways of diagnosing breast cancer?






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Suggest why early diagnosis of breast cancer incre

Cancer cells are less likely to have invaded other parts of the body

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Discuss role of specialists in health promotion in

- stop people starting/help them give up

-target specific groups.. so visit schools/work/clubs

- educate and inform people of harmful effects of smoking

- inform about benefits of giving up

- use leaflets/posters/adverts/websites/role models

-provide classes/discussion groups

-provide support/counselling

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Explain how smoking affects the unborn baby

nicotine in the smoke- constricts the placenta

-reduces oxygen/glucose getting to foetal tissue

-less energy avalaile for growth and less respiration so will affect babys weight

carbon monoxide- combines with haemoglobin

- reduces amount of oxygen transported by mothers blood to foetal tissue.

- less energy available for growth

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State possible effects of a mother smoking will pr

- premature

- lower birth weight

- misscarriages

-develop abnormalities

-poor brain development

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Describe two epidemiological evidence linking lung

- Lung cancer is rare in non-smokers

- Lung cancer increases as number of cigarettes smoked increases

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Explain how radiation and chemotherapy work?

radiation- ionizing/gamma radiation is targeted at the tumor which destroy the dna/cancer cells so can be used to shrink a tumor before surgery and involves daily treatment

chemotherapy- drugs targets at diving cells and involves interval treatment over several months.

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Explain complementary therapies of cancer?

- These look at working with the person as a whole not just the body part with cancer.

- holistic approach

- aim to make a person feel better while having cancer treatment and reduce side effects such as anxiety, sickness,tiredness,sleeping problems.

- hypnotheraphy, art therapy, meditation,relaxation,reiki.

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Whats is thermography

heat map of breast produced using a camera and infrared radiation

different colours respond to different levels of heat production in the tissues, warmer parts of the body give off more infrared 

As cancer cells produce more heat than normal cells as cancers form new blood vessels which release heat and have a high metabolic rate so tumours show up in warmer areas

a thermogram is then produced

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Suggest why thermography is not used to routine br

misses cancers in some woman as cant detect small/early tumours

gives positive results in women who dont have cancer

may generate heat from an infection/pregnancy

not used to diagnose cancer

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Explain surgical methods used to treat breast canc

lumpectomy- tumor is removed with border of normal breast tissue around it

mastectomy- removal of breast tissue

lymph gland removal- removal of lymph glands

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Describe the cell cycle with reference to interpha

Interphase- resting phase this is the time when the cell is not dividing or undergoing nuclear division.Cells spend most their time in interphase as this is when the cell's carrying out its functions and copying it chromosones for cell division consists of G1, S and G2

G1- first growth phase,proteins are being made and used to build up cell organelles and more cytoplase

Synthesis- where DNAs replicated

G2-second growth phase where cell organelles grow and divide,building up cells energy store

mitosis- when nuclues undergoes cell division used for growth,

Cytokinesis- when cell divides

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What is DNA?

deoxyribosnuclei acid is a molecule that stores genectic information, its present in the chromosones inside the nuclei of cells.

It has four organic bases:adenine,thymine,guanine and cytosine

purine bases:Adenine and Cytosine are made up of a 6 carbon ring joined to a five carbon ring

Pyrimidine bases:Thymine and Guanine are made up of a six sided ring.

Made up of nucleotides which join together in series of condensation reactions to form a polypeptide- DNA or RNA

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Whats DNA structure?

-made up of many repeated units called nucleotides which contain a deoxyribose sugar, a phoshate group and a organic nitrogenus base

-made up of two polypeptide chains one upside down that forms a double helix, the two strands are linked together by hydrogen bonds between the bases. A purine will only bind with a pyrimidine- Adenine with thymine and Cytosine with guanine. Adenine and thymine make 2 hyrodgen bonds whereas C and G make 3 this is known as complementary base pairing.

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Why is complementary base pairing important?

Complementary base pairing is very important in the conservation of the base sequence of DNA.

This is because adenine always pairs up with thymine and guanine always pairs up with cytosine.

As DNA replication is semi-conservative (one old strand an d one new strand make up the new DNA molecules), this complementary base pairing allows the two DNA molecules to be identical to each other as they have the same base sequence.

The new strands formed are complementary to their template strands but also identical to the other template. Therefore, complementary base pairing has a big role in the conservation of the base sequence of DNA.

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Outline process of DNA replication?

- semi-conservative replication

- occurs during s phase of cell cycle

- DNA molecule unwinds and unzips the double strands breaking H bonds between bases which separates them this is done by enzyme helicase.

- New DNA nucleotides pair up with exsposed bases, according to complementary base pairing:purine with pyrimidine: a with t and c with g

- new nucleotides are joined together by enzyme DNA polymerase

- a phosphodiester bond form between sugar of one nucleotide and phosphate of next 

- forming two completely identical strands of DNA

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Outline processes taking part in G1 + G2 points in

G1- cells grow and make proteins which build up to make organelles and more cytoplasm

G2- cell keeps growing cell organelles grow and divide and cell build up its energy stores

there also act act as checkpoint for controlling the cell cycle G1 checkpoint trigger initation of S phase and replication of organelles whereas G2 triggers process that leads to mitosis.

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How is cell cycle controlled

time and duration of cell cycle is controlled by protein complexes cyclins and enzymes called cyclin-dependent kinases.

The cyclin activate the CDKs, which affect the cycle at specific checkpoints:

G1-triggers initative of s phase and the replication of organelles

G2- triggers processes that lead to mitosis

M- controls entrey to anaphase

cyclins and CDKS react to signals both inside and outside the cell. outside factors include hormones,drugs and other chemical binds to receptors on plasma membrane. EG DNA damages by uv radiation during G1 p21 binds to G1 cdks, this stops them being activated, so stopping cell cyle. allowing DNA to be repaired.

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describe mitosis

Prophase- chromosones condense and become more visable as darkly-stained structures

Metaphase- centrioles send out microtubles which create a spindle, centromeres on the chromosones attach to spindle fibres and this pulls the chromosones to the equator making them line up.

Anaphase- centromeres divide so two sister chromatids are pulled apart by spindle fibres to opposite poles of the cell

Telophase- spindle breaks down and nuclear membrane forms around chromosones which have decondense and are no longer visble

Cytokinesis--following mitosis the cytoplasm dividies and two new cells are formed. each new cell receives half of original cell organelles and half new,copied organelles

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Define apoptosis

-programmed cell death, process is controlled by signals inside or outside the cell

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Outline process of apoptosis

Cell shrinks

DNA and protein in nucleus break down

mitochondria in the cell break down

cell breaks up into small fragements wrapped in membrane

a phospholipid (phosphotidylserine) which is normally present on outside of cell membrane is placed on cell surface

phagocytic cells (macrophages) have protein receptors in plasma membrane which recpgnise phosphotodylserine and bind to it when this happens the cell engulfs them

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What are the reasons for apoptosis?

esstential for normal growth and repair:

shredding of endometrium during menustration

firming synpases- between neurones in brain requires apop of surplus cells around them

fetus-fingers and toes are formed by removal of tissue inbetween them by apop

to destroy cells at risk to the organism- cells infected by virus,cells with damaged DNA

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Explain how damage to P53 gene can lead to DNA dam

P53 is a tumour suppressor gene they code for proteins (p21) which causes mutated cells to under apoptosis however Uv light penetrates skin cells and damages P53 which can lead to cancer as P53 can no longer detect the cells with damaged DNA so they continue to divide

Cigarette smoke contains benzopyrene which is absorbed by cells lining the respiratory tract where it converted to another chemical BPDE this binds to p53 which mutates it so it no longer works, therefore cells can then divide uncontrollable leading to the development of a tumor

If p53 mutates P21 is not made which means cyclin binds to CDK's and inactive RB as a result the cells will divide

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What is cancer?

cancer is uncontrolled cell division and a malignant tumour forms due to mitosis not needed for growth or repair. These tumours tend to spread to neighbouring tissues as cells from the tumours break off and spread to other parts of the body via blood and lymph systems, here they can start secondary tumours this is known as metastasis

however benign tumours can also form which are not cancerous as they grow in one place and do not spread to other parts of body. when removed by surgery its unlikely these will return e.g moles or uterine fibroids although they may press important nerves or blood vessles which causes harm

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Describe role ocogenes and protocogenes in develop

Genes called protocogenes stop a cell diving to often by:

carrying genetic code for growth factors:cyclins and CDK's

carrying genetic code for a receptor protein in membrane

protocogenes become ocogenes due to a mutation, a ocogene can lead to uncontrolled cell division as it may produce a receptor protein that triggers DNA replication when a growth factor is not present OR can causes excessive amounts of growth factor to be produced.

ocogene that leads to uncontrolled cell division leads to the formation of a tumour

cells lack differentation

and metastisis happens so tumour is transported round the body

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What causes cancer?

uv light- mutates p53

smoking- protien binds to p53

gene mutations- chemical- carcinogen


ionising radiation

Age-  MORE MUTATIONS -older people have had more contact with cancerous factors and more time to accumalate damaged DNA. immune system declines with age. DNA proof reading not as efficient- dna damge not detected/destroyed

heredity- some people inherit genes which can easily mutate to cause cancer- BRCA1 and 2 are examples of breast cancer gene woman with this have 60% chance of developing breast cancer

virus- viruses infect cells by inserting new genetic material , so cause changes in cells DNA- cervival cancer human papilloma virus

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Define stem cell

undifferentiated cell which has the ability to divide and form different kinds of cells

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Define stem cell

undifferentiated cell which has the ability to divide and form different kinds of cells

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Whats is differentiation?

when a cells matures and becomes specialised. some of the genes that cell contains are switched off as cell matures. this causes certain cell types to look different. once a cell has differentiated to a particular function/kind of cell it can no longer divide and produce more cells of different kinds

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Whats is differentiation?

when a cells matures and becomes specialised. some of the genes that cell contains are switched off as cell matures. this causes certain cell types to look different. once a cell has differentiated to a particular function/kind of cell it can no longer divide and produce more cells of different kinds

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Whats is differentiation?

when a cells matures and becomes specialised. some of the genes that cell contains are switched off as cell matures. this causes certain cell types to look different. once a cell has differentiated to a particular function/kind of cell it can no longer divide and produce more cells of different kinds

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Define totipotent stem cells?

cells which can divide into a whole new organism/cell 

e.g newly fertilised egg

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What are pluripotent stem cells?

A cell which can become any cell type but not whole organism

e.g cells from embryo( as differentation has started)

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What are multipotent cells

a stem cell such as bone marrow that can form several ranges of other cells

e.g different blood cells

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Explain how stem cells in bone marrow differentiat

-stem cells in bone marrow are called haemocytoblasts

rbcs are produced by haemoctyoblasts as each stem cell divides by mitosis,giving 8 or 16 proerythroblasts which are now commited to differentiate. As red blood cells develops: 

hb builds up

nucleus membrane breaks down and is extruded from the cell

cell organelles lost such as mitochondria

cell gradually gets smaller

monoblasts develop into monocytes in bone marrow and then mature in blood to become marcophages

lymphoblasts migrate to thymus gland where they divide and mature into lymphocytes

myeloblasts mature into other kinds of leucocytes-neutrophils

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Potential uses of stem cells?

- treat medical conditions such as parkisons,alzheimers, heart,stroke,athritis,diabetes,spinal damage

- use to test effects of experimental drugs

-studied to improve our knowledge of how diseases develop

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Concerns with use of stem cells in medicine

- some people argue embryos represent a potential life

-scientists argue that stem cell therapy may lead to a virus being passed on to someone

- some people are worried stem cells could become cancerous

- media used to grow stem cells use nutrients of animals, small risk diseases will pass from animal to human

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Why might eating processed meat increase risk of b

-hb and myglobin found in red meat trigger process nitosation in the gut which leads to formation of carcinogens

-compounds heterocyclic amines created in cooking process are carcinogens however these are found in poultry which has not been linked to cancer risk

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What is a CT scan

computerised tomography scan

paitient lies down on a platform which slowly moves through a hole in the ct machine.the machine is ring shaped and paitent is turned around and x-rays are taken in all different angles and a 3d image of the body is formed which makes it easier to see the tumour and its size

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How do x-rays work?

high energy radaition which give of photons

photons pass through soft parts of body but are absorb by denser parts-tumours

paitents has electrodes one side of body and a camera with photographic film the other side which records patterns of x-rays passing through the body.

denser parts of body appear white on the film

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What is a mammography

use of low dose x-rays to dectect tumours in the breast

low dose x-ray passed through breast if any unusal lumps detected further tests will be taken

offered on NHS to women over 50

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How does ultrasound work?

sound waves are used to build up an image of body part which may contain the tumour

cheap and portable than other methods

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What is a MRI scan

magentic resonance imagery

paitents lies on a large magnet which measures magentic field in different parts of body and computer puts these measurements together to form 3d image

more detailed than ct scan however more exspenive, uncomfortable long and noisy process

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What is a PET scan

positron emmison tomography

paitents injected with radioactive substance which breaks down and releases gamma rays.

gamma rays are detected and the pattern is used to build 3d image of body

most metabolic parts give off more gamma radiation-cancer

exspensive and only few in world

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Define term prevalence with refrence to breast can

prevalence-number of exsisting cases of diseases in a given population in a given time

breast cancer is more likely to develop after menopause- which in most woman is 50 and over this is due to oestrogen levels fall and oestrogen protect against development of breast cancer

however theyre many other risk factors:

starting puberty early

having late menopause

family history

drinking lots of alchol

being obese

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How does tamoxifen work?

hormone treatment which blocks oestrogen receptors on breast cancer cells which prevents it from getting into cancer cells as scientists found oestrogen encourages breast cancer to grow and divide

doesnt work for all breast cancers

to been taken 5 years

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What is Immunotherapy?

using drug herceptin which is an antibody that binds to protein receptors and blocks them so they cant causes rapid cell division

e.g vaccine for HPV

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What is insulin

A hormone which regulates blood glucose concentration levels

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What is Type 1 diabetes?

occurs when immune system has attacked the insulin-producing cells in pancreas. as a result pancreas produces little or no insulin. A person with type 1 their blood glucose levels become too low or too high, therefore no insulin is produced when levels are too high. if this is untreated can lead to unconscious and a coma.

treated with regular insulin injections

unknown cause but genetic and environmental factors 

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What is type 2 diabetes?

non insulin dependent 

commonest kind

due to not producing enough insulin and being insensitive to insulin thats produced

most common in people that have eaten a high sugar diet

insulin injections has no affect so theyre treated by being told to control their diet and exercise to eat more complex carbs as these are digested slowly into glucose avioding a rapid rise in glucose levels in the blood. advised to eat less sugar/salt and more vegs and fruit

caused by obesity,age,high bp,pyschical inactivity and family history of diabetics

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describe the link between diet and type 2 diabetes

diet high in sugar and salt add to diabetes as sugar raises blood glucose levels and salt increases water potential so increases bp junk food contains high energy compound which leads to obesity

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What are the health risks with diabetes?

uncontrolled diabetes leads to high blood glucose levels which causes damage to nerve cells, damage to retina of eye- which can lead to blindness

high bp, heart disease, wounds will not heal, strokes, chronic infections

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What is the fasting blood glucose test?

paitent is told not to eat for 8-12 hours before taking the test then blood sample is taken, if high blood glucose levels are shown its potentially diabetes 7.0 and above

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What is the glucose tolerance test?

asked to eat normally for days leading up to test then fast from midnight before test. a blood sample is taken when they arrive they then drink a high glucose liquid and another blood sample is taken every 30 mins for 3 hours and compared to standard to show how body uses glucose over time

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How is a blood sample taken?

-tie a band around the arm to make vein stand out, making it easier to target the needle

-clean area around vein with alcohol based solution

-push sterile needed into vein

-needle is attached to sterile syringe and as you pull back the syringe,blood is sucked into syringe

- remove needle and hold ball of cotton wool over the wound

-press for 2-3 minutes until bleeding has stopped and apply dressing

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Explain how biosensor are used and work?

monitor blood glucose

person places test strip in glucose test meter

disinfect skin with alcohol

place finger on sterile lacnet on device which pen pricks the skin

small amount of blood produced squeezed onto test strip

test strip contains enzyme glucose oxidase which converts any glucose into gluconolactone

as this happens a small electric current is produced, electrode on test strip picks this up and reading for blood glucose con is produced on digital screen

glucose test meter has a memory so can record  recent changes in blood glucose

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Explain why feeling thirsty is a symptom of diabet

high glucose levels in blood causes a reduction in blood water potent

meaning water will pass from tissues into blood by osmosis

as a result person will feel thirsty 

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explain how diabetes causes high bp?

water is drawn from blood via osmosis this increases vol of blood ,but capacity of blood vessels does not increase

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Reasons for increasing diabetes within populations

countries such as china and india are growing in wealth so plently more food is avaliable so theyre more likely to eat refined processed foods

people have cars and so taking less exercise

countries like brazil are less wealthy so more likely to eat fruit and veg

more people are migrating

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Whats difference between acute and chronic?

acute is a rapid onset disease which has a short duration but is severe e.g acute bronchitis

chronic often start slowing but are long term condition that are rarely cured e.g diabetes, chronic bronchitis caused by smoking

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How does smoking affect the respiratory system?

carbon monoxide gas diffuses through walls of alveoli into the blood. here it combines with hb to from carboxyhb which is unable to carry o2, carbon monoxide also increases heart rate as the heart has to pump more often to get the same amount of oxygen to body tissues.

 the tar in tabacco is deposited in bronchi, bronchoiles and alveoli. here they irrate epithelium and causes inflammation this paralyses the cilia on ciliated epithelium which means mucus is not moved towards the throat it stays in the lungs. mucus contains dirt and microorganisms therfore smokers are more likely to devlop lung infections. tar also stimulates globlet cells to realease more mucus this accumalated mucus leads to a persistand cough developing as body tries to get rid of it.

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How do mucus affect gas exchange in the lungs?

mucus reduces diameter of bronchi and bronchoiles which reduces the rate at which air can enter the alveoli

coughing damges the bronchi, bronchioles and alveoli which produces scar tissue which lowers rate of diffusion and increases diffusion pathway

infections in lungs lead to emphysema which the walls of alveoli break down. reducing surface aread for diffusion

mucus building up in lungs contain allergns-pollen which causes inflammation of bronchi and bronchioles which reduce the rate the air can enter alveoli and can lead to asthma attacks

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What is chronic bronchitis

build up of mucus in lungs which affects the resipartory system

condition develops slowly symptoms such as persistant cough and breathlessness

once developed its very difficult to improve syptoms

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What is emphysema?

lung disease caused by irratants in mucus which causes inflammination. as a result as large number of phagoytic white blood cells are attracted to alveoli. the elastase produced by these cells breaks down elastin and proteins of alveoli. healthy people have a inhibtor to stop tissue damage but in a smoker this has been inhibted. the alveoli becomes damaged and enlarged which reduces SA avaliable for gas exchange

this causes breathlessness and they breathe more deeply which prementately streches the elastin fibres as they do not have elastic recoil, this can eventually disable a person as they become so breathless they need oxygen from a cyclinder and it will usually lead to death

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What is chronic obstructive lung disease (COPD)?

chronic bronchitis and emphysema are both caused by smoking so two conditions occur together and this is said to be called COPD

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How does lung cancer occur

chemical carcinogen benezopyrene in tar form cigarette smoke binds to p53 which inactivates it and this causing epithelial cells which line the lungs to divide uncontrollably leading to formation of tumour

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What are symptoms of lung cancer?

breathlessness due to tumor blocking the airways and damging alveoli

persistant cough for same reasons

blood in sputum as a result of tumour damaging lung tissue


changed voice

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What happens during a asthma attack?

membranes lining the airways realease mucus which causing inflammination, this causes the airways to constrict (bronchoconstriction) and the mucus blocks the airways this causes wheezing as its difficult for air to escape

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What causes asthma

90 per cent of all asthma is caused by allergens as a allergic reaction happens when the immune system over-reacts to something in the the enviroment.

one cause is that the mother smokes during pregnancy which irratates the respiratory tract of children and increases the chances that they will develop allergic asthma

it can also run in the family

or loss of heat and moisture from lungs during strenous exercise can cause exercise induced asthma

breathing in chemical fumes,wood dust or other irratants for a long time can cause occupational asthma

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Whats the treatment for asthma?

steroids- which work by reducing the inflammation in the airways, they work long term so should reduce severity of asthma attacks and prevent asthma

beta-agaonists- are fast acting by relaxing the muscles in the airways during an asthma attack

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Define infectious and non-infectious disease?

infectious is caused by a pathogen and spread from one infected person to another e.g TB/HIV

non-infectious is not caused by pathogen and is not contagious e.g CHD,asthma

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What is atherosclerosis?

smooth endothelium is damaged due to high bp, which causes atheroma to build up on artery walls.

phagyotic cells migrate to the damaged area and accumalate lipids which form foam cells. 

tissues and fatty deposits build up underneath the damaged endothelium over many years and the growing plaque narrows the lumen of the artery

eventually the plaque breaks through the endothelium which causes a blood clot to form which makes the lumen even narrower.

the blood clot may grow so large in blocks the artery or the blood clot may break off (embolous) and travel in the blood until it reaches an artey which is too narrow for it to pass through. if the conoary artery is blocked in one of these ways this leads to a heart attack or myocardial infarcation which is when the muscle cells die due to lack of glucose and oxygen from conoary artery

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What is agina?

When conoary arteries become narrowed by atheroma and less blood can pass through these arteries to supply heart muscle.

problems occuring when exercises as faster respiration is needed so more o2 and glucose are needed but conoary artery is too narrow to supply this. this causes agina pectoris

people with this exeperience a pain in the centre of the chest but it can spread down left arm,towards jaw and down towards abdomen

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Distinguish between heart attack and cardiac arres

heart attack- heart muscle are straved of glucose and oxygen

cardiac arrest-heart stops beating

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describe first aid treatment for heart attack when

make casualty comfortable, sit them in supported position with knees bent

dial 999 and ask for ambulance

take any medication for heart condition

measure persons heart and breathing rate

note level of conscious

reassure them

if fall unconscious give cpr

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describe first aid treatment for CHD and unconscio

- send someone to fetch help and dial 999

- check wether person is breathing and whether they have a pulse

- if paitent has a pulse check airways are clear and carry out rescue breathing

- if person is not breathing a doesnt have a pulse lay person on back

- place hand on centre of the chest and place other hand on top interlocking fingers,keeping your arms straight press down 4-5 cm and then realease the pressure

- repeat 30 times at the rate of 100 compressions a minute then give two rescue breaths  continue this until help arrives

-if pulse returns just do resuce breaths if both returns place in recovery postion

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How does defibrillator work?

powerful electric shock is delivered to the heart

persons clothes and jewerelly are removed, two pads are placed on chest, one upper right and one lower left

pads are plugged into connector and the defibrillator will determine whether a shock is needed, both visual and auditory prompts will be given and operator will have to press a button to deliver a shock

machine may instruct operater to give another shock, then should check for pulse and breathing rate, if no pulse carry on

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Why aspirin used for heart attacks?

reduces ablity of platlets to cause blood clotting

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What are the risk factors of CHD?

diet- high salt rises bp, high in saturated fat raises blood cholestrol which lead to obesity and CHD, however some contain antioxidants which prevent it such as vitamin c in fruit

blood p-  high bp leads to damage of endothelium and increased chances of athroma developing

exercise- lowers bp and blood chlosterol  preventing CHD

genes- contain genes which make them prone to high bp and chlosterol. men are more than women until menopause

smoking- biggest factor causes high bp and chances of blood clots forming

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how do you calculate BMI

weight (kg) dividied by height (m) squared

bmi between 20 and 24.9 is ideal 

25 or higher are considered to be overweight

over 30 seen to be obese

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What is central adiposity

fat building up around the abdomen

can determine this by measuring waist cimcumfence in cm, men should be less than 90 and women should be less than 80

or waist to hip ratio where they measure waist at the height of the navel and hips around widest point and then divide. ideally ratio should be 1.0 or less in men and 0.8 in women

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What is angioplasty?

treatment of CHD

involves inserting a tiny hollow felexiable tube called a catheter into artery in groin or arm

at tip of catheter is a tiny inflatable ballon, the catheter is pushed along the artery until it reaches the conoary artery

when catheter arrives at a narrowed or blocked section the ballon inflates  squashing the fatty atheroma that has narrowed the artery.

most the ballons contain a stent, a tube of stainless tube mesh which expands when ballon is inflated and stays there afterwards holding narrow blood vessel open

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What is conoary bypass surgery?

used to treat blocked arteries of CHD 

in operation a peice of vein is taken from elsewhere in the body often the leg and is then used to bypass the blockage in conoary artery.

people may have many bypasses depending on number of blocked arteries

usually heart is stopped and a machine is used to pump blood around the body

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How can drugs be used for CHD

statins drugs to reduce chlosterol levels

beta blockers to reduce blood pressure

aspirin to stop blood clotting

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What is epidemiology?

study of occurrence, distribution and control of diseases in different populations

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What is incidence and incidence rate?

-number of new cases of a specific illness diagnosed or reported during a stated time period-usually a year

- above divided by number of people at risk to the disease

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What is prevalence and prevalence rate?

Prevalence-number of current cases of an illness or condition at one time, no matter when it started

above divided by total no of people who are at risk for illness or condition

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What is mortality rate

number of deaths from a specific cause per 1000 people in the population,per year

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What are notifiable diseases?

An infectious disease which has to be notified to the local authority e.g food posioning,measles,mumps,rubella

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Define endemic, epidemic and pandemic

endemic- is a disease which is always present within the population

epedemic- sudden increase in a disease in a specific area

pandemic- rise of incidence of disease on a global scale

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Define vaccine

a preparation containing antigens.

these antigens will be indectical to the known pathogen and they will stimulate an primary respone so that memory B cells are made. meaning that if the person ever encounters real pathogen a faster secondary response will be produced

live antigen: consist of living microogranisms with same antigens as pathogen however they can no longer cause disease. this is known as attenuated strain of pathogen e.g mumps, measles

dead: microorganisms have been killed by chemicals and heat: although pathogen is dead,it still carries antigens that stimulate an immune response e.g hepatitis A

fragement of pathogen: such a viral coat component e.g HPV

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What is the non-specific immune response

bacteria cannot penetrate (unbroken) skin ;

blood clots to, seal wound / prevent bacteria entering ;

in, stomach / ******, kills bacteria / AW ;

acid conditions denature, proteins / enzymes ;

goblet cells produce mucus that traps bacteria ;

cilia / ciliated cells, remove mucus (and trapped bacteria) ;

lysozyme / enzymes, in tears ;

breaks down, bacteria / bacterial cell walls

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Whats the second defence in non-specific response

phagocytosis is a process carried out by neutrophil and monocytes

monocytes become macrophages in the bone marrow

damaged cells and tissues realeased cytokines which attract phagocytes

phagocytes recognise the bacteria as it becomes coated in plasma proteins-oponins

the phagocytes engulf bacteria, and it becomes enclosed in a membrane coated vesile called a phagosome.

lysomes contains digestive enzymes (lysins) which move towards the phagosome and fuse with it the lysins break down the bacterium, realeasing soluble products that diffuse into cytoplasm of phagocyte.

Inflammination- damaged tissue produce histamine which causes vasodiliation in capillaries, they become more peremeable,so more plasma escapes through capillaries into surrounding tissues and causes swelling. plamsa contains neutrophils,monocytes and proteins that help combat pathogens

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What is the specific response

When an foreign antigen (marcomolecule-glycoproteins) is detected, immune system produces a specific antibody

antibodies are proteins synthesised by B lymphocytes

antigens bind to variable region of antibody and the antibody destroys pathogen by either:

agglutination-antibodies cause bacterial cells to clump together,which makes it easier for phagocyctes to engulf them

preciptation- antibodys cause soluble antigens to precipatate out so they can be engulfed by phagocytes

neutralisation- antibodys can bind to toxins released by foreign cells which neutralises them so they cant harm

opsonins: include antibodies constant region of antibody binds to receptor site of plasma membrane of phagocytic cell while its varible region binds to antigen. the bacteria is held on the phagocytic cell so it can be engulfed

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What is the role of B lymphocytes

formed in stem cells and mature in bone marrow .

each have a differenet shape of receptor on plasma membrane, which is capable of making a different antibody. 

when the pathogen enters the body , one kind of b lymphocytes have receptore which fit the antigens on the pathogen,

this b lymphocyte divides by mitosis to produce a clone indentical B lymphocyte. some of these cells develop into plasma cells which secrete specific antibodies against the pathogen

or become memory b lymphocytes which can survive for decades do not secrete any antibodies but serve as bodies immunological memory of orginal antigen so if it invades again they divide rapidly to form more memory cells and plasma cells so the response is much faster and intense this is the sencondary immune response

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Describe role of T lymphocytes?

produced from stem cells but mature in thymus gland

also contain a receptor on cell surface membrane.

a macrophage which has digested a pathogen by phagocytosis presents an antigen on its cell surface membrane. 

t lymphocyte which right receptor binds to macrophage and t lymphocytes divide to from a clone of T lymphocytes

some develop into t killer that kill any cell carrying the specific antigen

other t helper which secrete chemicals that stimulate phagocytosis and antibody production by b lymphocytes

both produce memory cells which can respond to later infection by same pathogen

t suppressor lymphocyte wind down the actin of the immune system once pathogen has been destroyed.

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how do B lymphoctyes differentiate into plasma cel

Cell becomes much larger to house r.e.r and glogi appartus needed to synthesis the antibodies and package them into vesicles for exocytosis

these processes will require far more energy so more mitochondria will be needed

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Explain how its possible to have a cold many times

cold virus keeps changing its antigens, so antibodies against on strain will not be effective against antigens of different strain

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What is passive immunity and active immunity?

immunity can be aquired without the immune system being challenged by the antigen by recieving antibodies from another organism: such as across the placenta

active- is immunity developed in an organism by activation of antibodies by immune systems response to an antigen/pathogen

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What is natural and artificial immunity?

Natural- immunity to a disease which occurs as part of individual biological make up such as antibodies remaining from a previous infection or passed down from mother

Artificial- active immunity aqquired by a vaccination

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What is herd immunity?

the idea that once a certian porportion of the population is vaccinated, the chances of an infected person meeting a suspeceptible person and passing on pathogen is much lower so if the pathogen is not passed on, it cant multiply in the human host and the pathogen population becomes much smaller so the disease can no longer spread and people are protected.

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What are boosters?

vaccinations which are given in more than one dose to ensure that memory B cells are produced to give immunity against the disease. boost the number of memory cells

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Explain the ages children are given vaccinations?

2 months- polio, tetanus,diptheria, whooping cough hib

3 months- tetanus,diptheria,polio,meningitis C hib

4 months- same and pneumococcal infection, hib

around 12 months hib, meningitis C

around 13 months- measles,mumps,rubella

given again at 3 years to 5

rest of life given tetanus,polio,diptheria

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What affects herd immunity

how easily pathogen spreads

how effective vaccination is

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Why might someone need blood transfusion?

- major accident

- during surgical operation


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What happens if someone is given the wrong blood g

rbcs from donors blood will clump together/agglutinated by antibodies in receipents plasma

this can block  blood vessels and stop the circulation of blood to various parts of the body

they also break open and there contents leak out, hb becomes toxic when outside the cell 

so this can kill the paitent

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Explain blood groups?

four- A,B,AB and O

named accordingly to antigens on red blood cell surface membrane.

corresponding antibodies present in plasma

during blood transfusion antigens should not correspond and bind to antibody in recieptor plasma

blood group 0 can be given to anyone because there are no ABO antigens these are called universal donors

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Explain rhesus blood groups

many people have antigen rhesus factor or antigen D on rbcs surface, if they do RH+ if dont RH-, person with RH- doesnt have RH antibodies but can receive them if they receive blood from someone with RH+ and vie virsa without any problems

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What problems occurs from RH- mum and RH+ baby

antibodies from mother can pass across placenta into babys circulation and destroy fetal red blood cells. baby will be born stillborn or have haemolytic disease

pregnant women who are RH- are given injection of anti-rhesus early in pregnancy which stops them making any anti-rhesus antibodies by binding to RH+ cells and preventing mother from synthesising her own antibodies

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What are differences between prokaryotic cell and

prokaryotic do not have a nuclear membrane

DNA is circular and not complexed with protein , whereas eukaryotic has linear DNA with complexed protein

ribosomes are smaller

do not have membrane bound organelles such as mitochondria and r.e.r 

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What is TB and how is it spread and symptoms

mycobacterium tuberculosis

spread by person with TB coughs/sneezes and droplets of mucus containing bacterium into air, these are breathed in by another person and myobacterium infects lungs and also when person drinks unpasterised milk from cows infected with related mycobacterium bovis

symptoms: fever

loses weight

persistant cough and feels tired

this is primary infection in healthy immune system it will not travel any further

if disease develop blood sputum as lung tissue damaged, develop chest pain and suffer from night sweats

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How can TB be diagnosed and treated?

chest x-ray looking for cloudness

sample of sputum which is examined in lab for bacterium

treatment: antibiotics that must be taken for 6-9 months however people feel better because they destroy most suspectible strains of mycobaterium first  and so then they stop, this causes  bacteria to become resistant, multiply and spread to others

 to stop this they are given cocktal of three or four different drugs so atleast one will be effective 

best way to prevent it is vaccination BCG which is attenuated vaccine, contains live but weakend strand

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What is HIV

human immunodeficiency virus which casues disease AIDS- aquired immunodeficiency syndrome

it is a retrovirus, which its genectic information is in the form of RNA which is made using enzyme reverse transcriptase. it inserts itself into dna of t-helper lymphoctyes.

they do not have a cell structure and are many times smaller than bacteria, viruses can replicate only when they are inside a living cell-obiligate intracellular parasites

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How is HIV transmitted and how do you control spre

one infected person to another through body fluids- usually sexual intercourse

infected mother to her baby  during pregnancy and breast feeding

sharing of needles for drug abusers


screening blood for transfusion


needle exchange systems

educating people

offering hiv tests to people at risk

encouraging mothers with hiv not to breastfeed

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Outline precautions to reduce patients infected wi

improve sterilisation of surgical instruments

isolate people with MRSA

sterile bedding

improved hygiene

improved personal hygiene- alcohol based hand rub between every paitent

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