Organisation Flashcards
what is the cell hierarchy?
cell - basic building block of all living organisms
tissue - a group of similar cells working together to perform a specific function
organ - a group of similar tissues working together to perform a specific function
organ system - a group of similar organs working together to perform a specific function
organism - a group of similar organ systems working together to perform a specific function
what are the roles of the organ of the digestive system?
- salivary glands - produce saliva
- oesophagus - carries food from mouth to stomach
- stomach - has HCl to kill bacteria+right pH for pepsin (protease) to work, produces pepsin, churns food
- liver - produces bile (neutralises stomach acid+emulsifies fats)
- gall bladder - stores bile
- pancreas - produces protease, amylase, lipase + release the into small intestine
- small intestine - produces lipase, protease, amylase + digested food absorbed
- large intestine - absorbs water from waste
- rectum - where faeces are stored
what is digestion?
breakdown of large insoluble molecules into small soluble molecules so they can be absorbed into the blood
what are enzymes?
globular proteins which are also biological catalysts
what conditions are needed for enzymes to work?
temp - 37 C
pH - depends on the enzyme eg. pepsin works at pH 2 and amylase works best in alkaline conditions
when do enzymes denature (active site changes shape)?
when temp is above 37 C
when the pH isn’t right
what is the lock and key theory?
enzyme=lock
substrate=key
only one substrate can fit in the active site of an enzyme
what enzymes break down the different nutrients?
carbohydrases break carbs into simple sugars eg. amylase=starch into glucose
lipases
lipids=glycerol+fatty acids
proteases
protein=amino acids
where are the enzymes produced?
- amylase=pancreas, small intestine, salivary glands
- lipase=pancreas, small intestine
- protease=stomach (pepsin), pancreas, small intestine
what are the products of digestion used for?
- some glucose used for respiration
- build new carbs, proteins, lipids
how does bile aid digestion?
- alkaline to neutralise HCl
- emulsifies fat to form small droplets which increases the surface area
- alkaline conditions and large surface area increase the rate of fat breakdown by lipase
how does the heart pump blood?
- pumps blood around the body in a double circulatory system
- right ventricle pumps blood to the lungs where gas exchange takes place
- left ventricle pumps blood around the rest of the body
what path does blood take?
vena cava -> right atrium -> atrium contracts -> valve -> pulmonary artery -> lungs -> pulmonary vein -> valve -> left atrium -> left atrium contracts -> left ventricle -> left ventricle contracts -> aorta -> body
where are pacemaker cells found?
right atrium
control heart rate
what are artificial pacemakers?
devices that correct irregularities in heart rate
how are arteries adapted?
- thick layer of muscle+elastic fibres (stretch when blood comes at high pressure)
- thick walls
- small lumen
how are veins adapted?
- thin walls
- large lumen
- valves (prevent back flow of blood)
how are capillaries adapted?
- thin wall (one cell thick)
- narrow lumen
what is blood made of?
- plasma
- r.b.c
- w.b.c
- platelets
how are the components of blood adapted?
r.b.c
- biconcave= large surface area to absorb O2
- x nucleus=more space for O2
- contain haemoglobin which binds to O2
w.b.c
- phagocytosis (engulfing pathogens)
- produce antibodies/antitoxins for bacteria
platelets
- small fragments of cells
- x nucleus
- help clot wounds
plasma
- carries waste eg. CO2+urea
- hormones
- proteins
- antibodies/antitoxins
- glucose+amino acids
what are the parts of a lung?
- trachea
- bronchi which narrow into bronchioles which end in alveoli
how are alveoli adapted for gas exchange?
- surrounded by a capillary network
- blood from body (high in CO2)=oxygen diffuses out of alveoli+CO2 diffuses into alveoli=breathed out
- blood reaches body cells=oxygen release from rbc & diffuses into body cells+CO2 diffuses into body cells=carried back to lungs
- cauliflower shaped=large surface area
what is coronary heart disease (CHD)?
layers of fatty deposits build up in the coronary arteries, narrowing them=reduces the flow of blood through the coronary arteries=lack of oxygen for the heart muscle
how to treat CHD?
statins - drugs that reduce blood cholesterol
stents - wire mesh tube that widens arteries
pros and cons of statins
pros
- reduce ‘bad’ cholesterol (LDL) in blood=reduces risk of stroke, heart attacks, coronary heart disease
- increase amount of ‘good’ cholesterol (HDL)=can remove LDL from blood
- may prevent other diseases
cons
- long-term drug+taken regularly=someone may forget t take them
- negative side effects eg. headaches, kidney failure, liver damage, memory loss
- take time to cause an effect
pros and cons of stents
pros
- lower risk of heart attacks in people with CHD
- effective for long
- quick recovery time
cons
- risk of complications in surgery
- risk of infections
- risk of blood clot developing near stent (thrombosis)
why are faulty valves dangerous?
- valve won’t open properly
- valve may leak=blood can go both ways=blood x circulating effectively
how to treat faulty valves?
- valve replacement - either biological or mechanical
- less drastic than heart transplant but carries risks of blood clots+danger
why are artificial hearts used?
- to keep patients alive
whilst waiting for a heart transplant - to allow the heart to rest as an
aid to recovery
what are communicable diseases?
- disease that can be spread from person to person or animals to people
- caused by pathogens
what are non-communicable diseases?
- disease that cannot be spread from person to person or animals to people
- last for a long time+get worse overtime eg. asthma, cancer, allergies
what is health?
state of physical and mental well-being
what affects your health?
- diseases
- diet
- stress
- life situation eg. access to medicines
how can diseases interact?
- Defects in the immune system mean that an individual is more likely to suffer from infectious diseases eg. influenza
- Viruses living in cells can be the trigger for cancers eh. HPV can cause cervical cancer in women
- Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
- Severe physical ill health can lead to depression and other mental illness
what are the human+financial costs of non-communicable diseases globally/nationally, locally and individually?
human cost
- around 10 million people die from non-communicable diseases each year=may have lower quality of life+short life expectancy
- doesn’t only affect sufferers but their loved ones
financial cost
- expensive for NHS to research+treat the diseases (same around the world)
- families have to adapt or move house to help person with disease=costly
- person with disease stops work/dies=low income for family+affect country’s econmy
how does lifestyle affect the incidence of disease?
- in HICs=people have higher income=can buy high-fat food (global)
- people in deprived areas=more likely to smoke+poor diet+ x exercise=higher chance of diseases (national)
- individual choices affect local incidence of diseases
what are risk factors?
factors that are linked to an increased rate of a disease
examples of risk factors
- The effects of diet, smoking and exercise on cardiovascular disease.
- Obesity as a risk factor for Type 2 diabetes.
- The effect of alcohol on the liver and brain function.
- The effect of smoking on lung disease and lung cancer.
- The effects of smoking and alcohol on unborn babies.
- Carcinogens, including ionising radiation, as risk factors in cancer
what is cancer?
changes in cells which cause a rapid or uncontrolled growth
what are benign tumours?
- growths of abnormal cells which are contained in
one area, usually within a membrane - do not invade other parts of
the body
what are malignant tumours?
- cancers
- they invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours
what are lifestyle risk factors that affect cancers?
- smoking - lung/mouth/bowel/stomach/cervical cancer
- most preventable
- obesity - bowel/liver/kidney cancer
- second most preventable
- UV exposure - skin cancer
- viral infections - hepatitis B+C=liver cancer
how do genetics affect cancer?
you can inherit faulty genes=more likely to get cancer eg. BRCA gene=breast+ovarian cancer
what are the plant tissues?
- epidermal tissues
- palisade mesophyll
- spongy mesophyll
- xylem and phloem
- meristem tissue
how is a leaf adapted?
- waxy cuticle=reduces water loss+transparent=lets light through to palisade mesophyll
- palisade mesophyll=lots of chloroplasts+near top+upright+tightly packed=get more light for efficient photosynthesis
- spongy mesophyll=round+spread out=allow gases eg. CO2 to diffuse+reach palisade cells
- guard cells=flacid or turgid to open or close stomata=prevent transpiration
how are root hair cells adapted?
large surface area to absorb as much water as possible
how is the xylem adapted?
- transports water and mineral ions from the roots to the stems and leaves
- made of hollow tubes strengthened by lignin adapted for the
transport of water in the transpiration stream
how is the phloem adapted?
- transports dissolved sugars from the
leaves to the rest of the plant for immediate use or storage - made of tubes of elongated cells
- Cell sap can move from one phloem cell to the next through pores in the end walls
what is translocation?
movement of food molecules (sugars) through phloem tissue
what factors affect the rate of transpiration?
- low light intensity=stomata close=x photosynthesis in dark=minimises water loss
- high temp=particles have more energy=evaporate+diffuse out of stomata
- high wind intensity=water molecules swept away=low concentration of water outside=faster diffusion
- high humidity=water concentration is similar on outsisde+inside=slow diffuseion
