B5

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GCSE Biology (B5) Flashcards on B5, created by Anna Hollywood on 03/01/2014.
Anna Hollywood
Flashcards by Anna Hollywood, updated more than 1 year ago
Anna Hollywood
Created by Anna Hollywood almost 11 years ago
277
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Resource summary

Question Answer
What are the 4 advantages that an internal skeleton has over an external skeleton? Provides internal framework...grows with rest of body...flexible (has many joints)...allows easy attachment of muscles
What does a long bone consist of? Long shaft containing bone marrow and blood vessels - hollow so stronger and lighter than other bones
Why can cartilage on bone be infected? Because they are living tissues
How does the human skeleton turn from cartilage (when baby) to bone? Through ossification
What is ossification? The deposition of calcium and phophorous
Why are older people more prone to fractures? They lack calcium and phosphorous which can lead to osteoporosis
What do synovial joints (like ball and socket and hinge joints) consist of? Synovial fluid, a synovial membrane, ligaments and cartilage
What are antagonistic muscles and give an example Muscles that work in pairs. E.g. Biceps and triceps (to raise arm biceps contract and triceps relax and vice versa)
In a synovial joint, what does the synovial fluid do? Acts as a cushion against shock and as a lubricant for easy movement
In a synovial joint, what does the synovial membrane do? Holds in the synovial fluid
In a synovial joint, what does the cartilage do? Protects the bone head
In a synovial joint, what does the ligaments do? Holds the bone in place
What is raising and lowering the forearm an example of? A lever, with the elbow acting as a fulcrum (pivot) - effort is multiplied giving greater force
Why do most animals need a blood circulatory system? To ensure all cells receive enough food and oxygen and to remove waste products
What animal has a single circulatory system? Fish
What does a double circulatory system require and why? A four chambered heart (two atria (receive blood) and two ventricles (distribute blood)). This ensures high blood pressure for efficient and fast circulation
What does a single circulatory system require? A two-chambered heart, one two receive blood and one to distribute it
What improvement did Harvey make on Galen's theories on the circulatory system? Galen knew that the heart was a pump, but thought that the liver made blood. Harvey came up with the correct theory we know today
What is the definition of the cardiac cycle? The sequence of events as blood enters and leaves the heart
Explain briefly the cardiac cycle Two atria contract...two ventricles relax...blood goes in through atrio-ventricular valves...ventricles contract...force blood to lungs/body
What hormone increases your heart rate and why was it useful for our ancestors? Adrenaline - kicks in 'fight or flight' descision
What is a pacemaker? Keeps rhythm of heart using small electrical currents - can be made artificially
What is an electrocardiogram? Shows the changes in electrical impulses in heart muscle
What does the sinoatrial node (SAN) do? Makes atria contract...forces valves open and pushes blood into ventricles
What does the atrioventricular node (AVN) do? It is a patch of muscle fibres...conducts impulses to special conducting muscle fibres (purkyne fibres) which carry the impulses to the tip of the ventricles
What happens next? Two ventricles contract...closing AV valves...pushing blood out ventricles through open semilunar valves...into arteries...atria relax...fill with blood
What do they mean by a 'hole in the heart' and how can this be corrected? A hole in wall between 2 sides of heart, through 'open heart' surgery
Why is a 'hole in the heart' bad? It allows deoxygenated and oxygenated blood to mix meaning that less oxygenated blood is being carried to muscles meaning less energy
What's different between the circulatory system of a unborn baby and a new born baby? An unborn baby doesn't have a double circulatory system (lungs don't work yet) so it has a hole in the heart which closes when born
What does a heart with damaged or weak valves have? Low blood pressure and poor circulation (as blood will leak backwards)
How can a blocked coronary artery be sorted out? Through surgery/a transplant
How can major heart problems be sorted out? Transplant by donor heart or having a heart assist device which provides extra pressure (allowing heart to rest a bit and heal)
What are the positive things about heart surgery? Artificial pacemakers and valves can improve lives drastically and tissue/heart donors are plentiful
What are the negatives of heart surgery? Carries a lot of risk & to avoid rejection immune-suppressive drugs have to be taken
What does blood donation involve? Blood from volunteer...anti-coagulant drugs...find blood group...find out if have rhesus
What chemicals do doctors use to prevent the blood clotting? Heparin, warfarin, aspirin
What are the people with the inherited condition, haemophilia, at risk of? Internal bleeding (even at the slightest knock) due to the blood not being able to clot
What is the rhesus system? If you have the rhesus antigen you are positive, if you don't you are negative (A+ or A-)
What is the process of blood clotting called? A cascade process
Explain the process of clotting Blood platelets exposed to air...trigger complex sequence of chemical reactions...leads to meshwork of fibrin fibres (clot)
What is agglutination and when does it take place? Blood clumping when different blood groups are incompatible.
Why can agglutination be life-threatening? When red blood cells and blood plasma react
What can blood group A donate to? A and AB
What can blood group B donate to? B and AB
What can blood group AB donate to? AB
What can blood group O donate to? A, B, AB, O
What group/s can blood group A receive from? A and O
What group/s can blood group B receive from? B and O
What group/s can blood group AB receive from? A, B, AB and O
What group/s can blood group O receive from? O
What type of habitats are amphibians restricted to? Moist
What do amphibians use to obtain oxygen and what can this lead to? Their permeable skin which makes them more susceptible to excessive water loss (and death)
Why don't fish gills work in air? Because it involves the water being forced over filaments which extract the oxygen
What happens when a human breathes in? It depends on the contraction of the intercostal muscles. Ribs move up and out...diaphragm moves down...chest volume increases...pressure decreases...higher pressure outside causes air to enter lungs
What happens when a human breathes out? Intercostal muscles and diaphragm relax...ribs move down and in...diaphragm curves up...chest volume decreases...increases pressure...forces air out lungs
Tidal air amount of air normally breathed in and out when at rest
Vital capacity maximum amount of air that can be exchanged
Residual air amount of air that cannot be forced out of lungs
why does diffusion occur in lungs? oxygen concentration in air is higher than in deoxygenated capillaries around the alveoli
how are exchange surfaces adapted for their function? large surface area...good blood supply...permeable...moist...one cell thick
What are the readings on a spirometer? A measure of different lung capacities and the rate of air flow. They can help to diagnose lung diseases.
asbestosis an industrial disease resulting from breathing in asbestos fibres...causing inflammation...scarring of lung tissue...reducing gaseous exchange
What happens when you get lung cancer? Lung cells grow rapidly, reducing surface area available for gaseous exchange
3 symptoms of asthma wheezing, tight chest, difficulty breathing
How is the respiratory system different for fish (than it is for humans)? What does this mean? Fish - Through flow of water Humans - Air goes in and out of structure....chemical particles like tar can become trapped in air sacs
What happens during an asthma attack? Lining of airways become inflamed, mucus and fluid build up and bronchioles contract, narrowing the airways
Name 2 reasons why physical digestion is important -allows food pass easily through digestive system -prepares food for chemical digestion (gives it larger S.A)
Give 2 forms of physical digestion Chewing the food in your mouth and squeezing food in your stomach
How and where is starch (carbohydrate) digested? By carbohydrase in the mouth and small intestine...converted to maltose...then to glucose
How and where is protein digested? By protease in stomach and small intestine into amino acids
How and where is fat digested? By lipase in the small intestine into fatty acids and glycerol
How does pH vary with enzymes? Protease enzymes like pepsin need a low pH while other protease enzymes in mouth and small intestine need a higher pH
What does the gall bladder store and what does it do with it? Bile, released into small intestine to emulsify fats, increasing their S.A for efficient digestion
What do food molecules need to be able to do? Pass through walls of small intestine and dissolve in blood/lymph
Where do the digested carbohydrates and protein molecules go? Diffuse through walls of small intestine into blood
Where do the digested fat molecules go? Not soluble so diffuse though walls of small intestine into lymph
6 adaptations of small intestine Very long...large S.A due to villi...microvilli increase S.A...thin lining...good blood supply...extensive lymphatic system of lacteals which contain lymph
What are excess and amino acids broken down into and where? In the liver they form urea, which is taken in the blood to the kidneys
Where does blood containing waste go? enters each kidney via renal artery
Where does blood not containing waste go? Leaves by renal vein
What does each kidney have and how does waste leave the kidney? An outer cortex and an inner medulla ... leaves through ureter as urine
What happens when the blood flows through the kidney under high pressure? Filtration happens (under high pressure) to remove wastes...useful materials like water, glucose and salt are reabsorbed back into blood
What else does the kidney do? Regulates salt and water levels in body
What is a nephron? A microscopic kidney tubule where filtration occurs (each kidney has millions of these)
What is a glomerulus? A network of capillaries where high pressure filtration occurs
What other regions does a nephron have? region where selective reabsorption happens (glucose passes into blood)...region of salt and water regulation
What is a dialysis machine and what does it do? Used when someone has a kidney failure and acts as a replacement, filtering out urea and increasing pressure for diffusion
What does dialysis fluid contain and why? Sodium salts to replicate desired blood concentration and keeps sodium levels in the blood
How is urea made? excess amino acids converted into ammonia...converted by liver into urea
What happens when you have a large drink of water? Quantity of urine production rises and urine concentration decreases
What happens when you don't drink enough? Concentration of blood increases...high concentration detected by hypothalamus...pituitary gland releases ADH...kidney tubules reabsorb more water...more concentrated urine
What happens when you drink too much water? Concentration of blood decreases...low concentration detected by hypothalamus...pituitary gland doesn't release as much ADH...kidney tubules reabsorb less water...more dilute urine
Why must carbon dioxide be removed from the body? Because it's toxic
How are carbon dioxide levels maintained? Increase in co2 detected by receptors in carotid artery...nerve impulses tell brain...rate of breathing increases...more co2 removed
What are the 4 sex hormones used in the female menstrual cycle and where are they produced? FSH (stimulates egg to develop in ovary) - pituitary gland LH (controls ovulation) - pituitary gland Progesterone (maintains uterus wall) - ovaries Oestrogen (repairs uterus wall) - ovaries
What controls the negative feedback system for the menstrual cycle? The receptors in the hypothalamus
What happens to the levels of oestrogen and progesterone if fertilisation doesn't occur? They decrease
When does menstruation occur (in terms of oestrogen and progesterone levels)? When oestrogen and progesterone levels are low
Why, when an egg is fertilised, do progesterone levels stay high and no FSH is produced? So the uterus lining does not break down and so no more eggs develop
How can artificial sex hormones control fertility? Prevents it by making the body think it's pregnant, stopping FSH production.
Name 2 reasons for male and 2 reasons for female infertility Male - not enough fertile sperm/sperm duct blocked Female - no eggs developed or released/fallopian tubes being blocked
Name 6 treatments for infertility -artificial insemination(injecting sperm into uterus) -using FSH to stimulate egg development -IVF(egg is fertilised outside body) -Egg donation -Surrogacy(fertilised egg put in another woman) -Ovary transplant
Which 3 treatments have big medical issues? egg donation, surrogacy, ovary transplants
4 problems with IVF Expensive, low rate of success (25%), risk of multiple births and lower birth rate
Name 2 ways in which baby abnormalities can be checked -Amniocentesis (extracting and testing cells in the amniotic fluid) -Chromosomal analysis (testing blood for chromosome abnormalities)
What are the problems with foetal screening? Whether it's right to interfere with nature, whether an unborn foetus has the right to life, risk of foetus expulsion
What can help increase growth? Balanced diet (calcium, phosphorous, vitamin D, proteins) and regular excercise
What are extremes of height caused by? hormone imbalance, genes
What are the 5 main stages of growth? Infancy, childhood, adolescence, maturity, old age
Why are babies' growth usually monitored for the first 6 months? To check for any growth abnormalities
Where is the human growth hormone produced? In the pituitary gland (stimulates growth mainly in long bones)
5 factors for life expectancy growth better housing...healthier diets...healthier lifestyles...less industrial disease...more effective cures
How does this life expectancy increase effect people on a personal level? May not be able to enjoy life fully if ill, less jobs for youth
How does this life expectancy increase effect people on a national level? Burdens on health service and pension funds
Why are their limited organs? Restricted by size, age, shortage of donors
4 problems with mechanical replacements dependence on power supply...properties of material...large size...body's reaction
What can living donors donate? blood, bone marrow, kidney
3 things that a dead donor can donate cornea, heart, liver
Problems with dead donors -many not be 'brain dead' -other ethical and religious issues
What 2 things are needed to ensure a successful transplant? -Tissue matching(avoid rejection) -Immuno-suppressant drugs
What is an opt-out system? Some countries assume that they can take your organs when you die so you have to opt out of the system
A problem with immuno-suppressive drugs Can lead to body not being able to protect itself from pathogens and other harmful micro-organisms
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