organisation Flashcards
what is a cell?
the basic building block of a living organism
what is a tissue?
a group of cells with a similar structure and function working together
what is an organ?
a collection of tissues working together rot perform a specific function
what is an organ system?
a group of organs working together to perform specific functions.
what is the main function of the digestive system?
to digest food and absorb the nutrients obtained from digestion
what is the role of the pancreas and salivary gland in the digestive system?
the pancreas and the salivary glands are glands which produce digestive juices containing enzymes
what is the role of the stomach in the digestive system?
produces hydrochloric acid, which kills ant bacteria present and provides the optimum acidic PH for the protease enzyme to function
what is the role of the small intestine in the digestive system?
the small intestine is the site where soluble food molecules are absorbed into the bloodstream
what is the role of the liver in the digestive system?
produces bile (stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work more efficiently
what is the role of the large intestine in the digestive system?
absorbs water from undigested food, producing faeces
what is the role of enzymes in the digestive system
enzymes act as biological catalysts which speed up the rate of biological reactions (the breakdown of food) without being used up
how does the shape of an enzyme affect its function?
enzymes have a specific active site which is complementary to their substrate
what is metabolism
the sum of all the reactions in a cell or an organism
what types of metabolic reactions do enzymes catalyze
- build larger molecules from smaller molecules
- changing one molecule to another
- breaking down larger molecules into smaller molecules
what is the lock and key hypothesis of enzyme function?
the shape of the enzyme active site and the substrate are complementary, so it can bind together to form an enzyme-substrate complex
how does temperature affect enzyme action
up to a certain point, increasing temperature increases enzyme action, as molecules have higher kinetic energy. however, above a certain temp, the shape of the active site is altered and the enzyme becomes denatured. so it can no longer catalyse the reaction. the optimum temperature is around 37.
how does PH affect enzyme function?
the optimum PH for most enzymes is 7. If the PH is too extreme, the shape of the active site may be altered and the enzyme may no longer work
where are carbohydrates produced in the body?
amylase: salivary gland
pancrease and maltase: small intestine
where are proteases produced in the body?
pepsin: stomach
others: pancreas and small intestine
where are lipases produced in the body?
pancreas and small intestine
what is the role of carbohydrates in the digestive system?
carbohydrates break down carbohydrates into monosaccharides and disaccharides. amylase breaks down starch into maltose, and maltase breaks down maltose into glucose
what is the role of the protease in the digestive system?
protease breaks down proteins into amino acids
what is the role of lipases in the digestive system?
lipase break down lipids into fatty acids and glycerol
how are the products of digestion used?
they are used to build bigger molecules such as carbohydrates and proteins. glucose is used as a substrate in respiration
where is bile made and stored in the body?
bile is made by the liver and stored in the gallbladder
what is the role of bile in the digestive system?
- bile is an alkaline substrate which neutralizes the hydraulic acid in the stomach
- bile emulsifies lipids to form droplets, this increases the surface area for the lipase enzyme to work on
what is the heart?
an organ that pumps blood around the body
what is the purpose of the circulatory system?
carries oxygen and other useful substances to bodily tissues and removes waste substances
how does the double circulatory system work
- one pathway carries blood from the heart to the lungs
- one pathway carries blood from the heart to the tissues
where does blood pumped by the right ventricle go
the lungs
where does blood pumped by the left ventricle go
body tissues
why is the double circulatory system important?
it makes the circulatory system more efficent
how many chambers does the heart have
4
what are the names of the heart chambers?
right atrium
left atrium
right ventricle
left ventricle
why is the wall of the left ventricle thicker?
the left ventricle has to pump blood at a higher blood pressure around the whole body
what is the role of the aorta?
carries oxygenated blood from the heart to the body
what is the role of the pulmonary vein?
carries oxygenated blood from the lungs to the heart
what is the role of the vena cava
carries deoxygenated blood from the body to the heart
what is the role of the pulmonary artery?
carries deoxygenated blood from the heart to the lungs
what are the 4 main blood vessels associated with the heart?
aorta
pulmonary vein
vena cava
pulmonary vein
what is the purpose of valves in the heart?
prevent backflow of blood
what is the purpose of the coronary arteries?
coronary arteries supply the heart muscle with oxygenated blood
describe the process of blood flow through the heart
- blood enters the right atrium via the vena cava and the left atrium via the pulmonary vein
- the atria contract, forcing blood into the ventricles and causing the valves to shut
- after the ventricles contract, blood in the right ventricle enters the pulmonary artery (to the lungs) and blood in the left ventricle enters the aorta (to the body)
what is the approximate value of the natural resting heart rate?
70 beats per minute
how is the heart rate controlled?
heart rate is controlled by a group of cells in the right atrium which acts as a pacemaker
the release waves of electrical activity which cause the heart muscle to contract
how can an abnormal heart rhythm be treated?
irregular heart rhythms can be treated used an artificial pacemaker, which sends out electrical signals to correct the hearts rhythms
what are the three types of a blood vessels in the body?
arteries
veins
capillaries
how are arteries adapted for their function?
function: carry blood away from the heart
thick muscle layer: adds strength to resist high-pressure
thick elastic layer: allows arteries to stretch and recoil - in order to withstand high pressure
how are veins adapted for their function?
function: carry blood towards the heart
wide lumen: enables low-pressure
have valves: prevents backflow of blood
how are the capillaries adapared for their function
function: enable the transfer of substances between the blood and tissues
thin walls (one cell thick): short diffusion path
permeable walls: substances can diffuse across easlily and quickly
narrow lumen: blood moves slowly, more time for diffusion
how to calculate the rate of blood flow
volume of blood / number of minutes
where are the lungs found in the body?
located in the thorax ( in the chest )
protected by ribcage and separated from the rest of the abdomen by the diaphragm
what tissues make up the gas exchange system
trachea
intercostal muscles
bronchi
bronchioles
alveoli
diaphram
how are the lungs ventilated by the action of intercostal muscles
- intercostal muscles contract
- rib cage moves upwards and outwards
- diaphragm flattens and the volume of the chest increases
- increased volume results in decreased pressure
- air is drawn into the lungs down the pressure gradient
the inverse occurs when air moves out of the lungs
describe how gas exchange occurs are the alveoli
oxygen diffuses from the alveoli into the capillary bloodstream down its concentration gradient
carbon dioxide diffuses from the capillary into the alveoli down its concentration gradient
describe how alveoli are adapted to gas exchange
- small and arranged in clusters: large surface area
- rich blood supply: maintains concentration gradient
- thin walls: short diffusion pathway
how to calculate breathing rate
number of breaths / number of minutes
what substance carries the different components of blood around the body
plasma
what substances are transported by plasma
red blood cells
white blood cells
platelets
carbon dioxide
urea
products of digestion
what is plasma
a yellow liquid within blood that transports substances around the body
what is the purpose of red blood cells in the blood
transport oxygen around the body
how are red blood cells adapted for their function?
- biconcave shape: increased surface area to volume ratio
- no nucleus: more room for hemoglobin to bind oxygen
- contain haemoglobin: binds oxygen
what is the purpose of white blood cells in blood?
they form part of the immune system, which protects the body from invading pathogens
how are white blood cells adapted for their function?
- have a nucleus: contains DNA which codes for a protein
- can produce antibodies
- can produce antitoxins
- can engulf and digest pathogens (phagocytosis)
what is the purpose of platelets in blood?
platelets are small cell fragments which aid the clotting of blood at the sight of the wound
why is the function of platelets important
Platelets aid in the process of blood clotting. as a result red blood cells are trapped in the fibrin network, forming a clot that prevents excessive bleeding. scab formation (after the clot has dried) prevents bacteria from entering the wound
what is coronary heart disease?
coronary disease occurs when the coronary arteries that supply the heart muscle become blocked with a build-up of fatty material. this restricts the supply of oxygen to the heart, possibly leading to a heart attack or death
what is a stent and how does it work
a stent in a metal mesh tube, that is inserted into a blocked artery so that remains open. the stent is inflated used a balloon which is later removed to let the blood move freely
advantages of stents
- insertion can be carried out without general anesthetic
- quick recovery time
- lower the risk of a heart attack
disadvantages of stents
risk of postoperative infection
risk of blood clots at site of stent
what are statins
statins are drugs which reduce the level of LDL bad cholesterol which contributes to the development of the coronary heart disease
advantages of statins
reduce risk of stroke, coronary heart disease, and heart attacks
increases level of HDL cholestrol
disadvantage of statins
have to take continously
may have side effects
effect may not be immediate
what is a heart bypass surgery?
a surgery where blocked coronary arteries are replaced with sections of veins taken from other parts of the body
consequences of leaky heart valves
blood flows in the wrong direction, causing the heart to become less efficient. patients may become breathless and die as a result
what types of valves can replace leaky valves?
mechanical (plastic or metal)
biological (animals or sometimes human)
advantages of mechanical valves
lasts a long time
the disadvantage of mechanical valve
need to take medication to prevent blood clotting
advantage of biological valves
work very well
no medication provided
disadvantages of biological valves
only lasts 12-15 years
what is the purpose of an artificial heart?
artificial hearts are intended to support a patients hearts while they wait for a suitable donor heart
advantages of artificial hearts
less likely to be rejected by immune system
allows damaged heart to test to help recovery
disadvantages of artificial hearts
risk of infection due to surgery
risk of blood clots
have to take blood-thinning drugs
what is health
health is a state of physical and metal wellbeing
what is a communicable disease?
a disease cause by a pathogen which can be transmitted from one person to another
example of communicable disease
the flu
what is a non-communicable disease?
a disease which cannot be transmitted from a person to person
example of non-communicable disease
cancer
how can a diet affect health?
to little food
lack of nutrition: anaemia (vitamin deficiencies)
to much food
to much unhealthy food (obesity, type 2 diabetes)
how can stress affect health?
prolonged stress is linked to a wide range of health problems including heart diseases, cancer and mental issues
how can life situations affect health?
many life factors such as location, genre and financial status, ethnic groups, and healthcare provisions can impact a person’s mental and physical health
what is a risk factor
a risk factor is an aspect of a persons lifestyle or a substance found in the body or the environment which can increase the risk of a disease
how can diet affect the development of cardiovascular disease
high levels LDL cholesterol causes arteris to become blocked, increasing blood pressure and the risk of a heart attack
how can smoking affect the development of cardiovascular disease?
nicotine increase heart rate, other chemicals damage the artery lining and increase blood pressure
how can exercise affect the development of cardiovascular disease?
lowers blood pressure, reducing strain on heart
how can obesity affect the development of type 2 diabetes?
obesity is strongly linked with the onset of type 2 diabetes. a disease in which the body stops responding to insulin
how does alcohol affect liver and brain function?
excessive long-term alcohol use may lead to liver cirrhosis (scarring of the liver)
increased risk of liver cancer
damages brain tissue and nerve cells
how does smoking affect the development of lung disease and lung cancer?
tar in tobacco can damage the alveoli of the lungs, leading to chronic obstructive pulmonary diseaase
tar also damages the cells that line the lungs, leading the lung cancer
how do smoking and alcohol affect unborn babies?
carbon monoxide from tobacco smoke reduces the amount of oxygen the fetus receives
alcohol passes across the placenta and damages the developing fetus
what is cancer
cancer is the development of a tumour as a result of uncontrolled cell division
what is a benign tumor?
a tumor that is contained in one location, usually within a membrane
they are not cancerous and do not invade other parts of the body
can grow large very quickly
can cause damage to other organs
what is a malignant tumor
a tumour that can spread around the body via the blood and lymphatic system
can invade other tissues
cells divide more rapidly and have a longer lifespan
disrupts healthy tissues and may lead to death
factors that can lead to cancer
genetics
smoking
obesity
ionizing radiation
viral infections
