b2 Flashcards
name all organs that food passes directly through
mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus
name the organs which help food digest but food doesn’t pass through them
liver, pancreas, gall bladder
where do the nutrients go in order to travel around the body to the cells
the bloodstream
in which organ do do nutrients absorb into the bloodstream
intestines
how does the stomach digest food?
contains hydrochloric acid and bacteria for chemical break down. the muscles in the stomach use mechanical churning
how does the oesophagus digest food?
peristalsis is when the oesophagus contracts and relaxes to push food down the stomach
how does the small intestine digest food?
enzymes break down the carbohydrates, lipids and proteins in the food. these enzymes break down the insoluble food into soluble substances which are absorbed into the bloodstream in the villi
how do the rectum and anus help digestion
faeces is stored here until it’s ready to be pushed out
how does the large intestine digest food
it helps with the absorption of water
what is bile
bile is an alkaline substance that neutralises the acid and makes the conditions alkaline so enzymes in the small intestine can work better
which side of the heart does deoxygenated blood travel through?
right
which side of the heart does oxygenated blood travel through?
left
what is the function of the vena cava
vena cava carries deoxygenated blood from the body to the right atrium
where does deoxygenated blood travel
deoxygenated blood travels
- through vena cava to right atrium
- through valves to right ventricle
- through valves to pulmonary artery
- to the lungs
where does oxygenated blood travel?
oxygenated blood travels
- from the lungs through the pulmonary vein
- into left atrium
- through valves to left ventricle
- through valves to aorta
- to the body
what is the function of the valves?
valves prevent the back flow of blood
what is the function of the arteries?
arteries carry blood at high pressure away from the heart towards organs
what is the function of the veins?
veins carry blood at lower pressure back towards the heart
what is the function of the capillary?
capillaries provide exchange of materials (oxygen/carbon dioxide) from cells
describe the structure of arteries
- thick walls
- strong elastic fibres
- narrow lumen
- no valves
describe the structure of the veins
- thinner walls
- wide lumen
- valves
describe the structure of capillaries
- very small
- permeable walls
- one cell thick walls
- very narrow lumen
why are capillary walls one cell thick
increase diffusion rate
(exchange of materials)
how is oxygen transported around the body?
- in the lungs oxygen diffuses into the blood
- oxygen combines with haemoglobin to form oxyhaemoglobin
- red blood cells transport it around body
- oxyhaemoglobin spilts up so oxygen can be released into cells for respiration
name the function and adaptations of red blood cells
red blood cells transport oxygen around the body
- biconcave shape to increase surface area to carry more oxygen
- no nucleus : more space
- lots of haemoglobin : carry oxygen
what is the pigment found in the red blood cell
haemoglobin
what are platelets
platelets are small fragments of cells
do platelets have a nucleus
no
what is the function of platelets
to cause scabbing to clot the blood and stop the wound from getting infected
what would happen without platelets if you got cut
excessive bleeding
list the 6 biological materials that plasma carries
- red and white blood cells
- urea
- hormones
- nutrients ( glucose and amino acids )
- antibodies and antitoxins
- carbon dioxide
what does coronary heart disease affect?
coronary heart disease affects the arteries that supply blood to the heart
name three treatments for coronary heart disease
- stents
- statins
- artificial hearts
how are stents used to treat coronary heart disease
wire mesh tube inserted into (coronary) arteries.
keeps artery open so blood can flow through
what are the advantages of the use of stents to treat coronary heart disease
- lowers the risk of heart attacks
- quick recovery time from surgery
what are the disadvantages of the use of stents to treat coronary heart disease
- risk of complications during the surgery
- risk of blood clot near stent (thrombosis)
how are statins used to treat coronary heart disease
- drugs used to reduce the amount of bad cholesterol in bloodstream
- slows down the rate of fatty deposits so keeps blood flowing
what are the advantages of the use of statins to treat coronary heart disease
- can reduce the risk of strokes
- can reduce the risk of heart disease
what are the disadvantages of the use of statins to treat coronary heart disease
- patients may forget to take them
- negative side effects (like headaches)
- takes time to work
how are artificial hearts used to treat coronary heart disease
mechanical device that pumps blood for someone whose heart has failed or can’t get a donor
what are the advantages of the use of artificial hearts to treat coronary heart disease
- less likely to be rejected by the body than a human heart
what are the disadvantages of the use of artificial hearts to treat coronary heart disease
- surgery complications
- parts could wear out
- can be blood clots or strokes as blood doesn’t flow as smoothly
why are replacement heart valves used
needed if valves are weakened by infection or old age
what is a disadvantage of replacement heart valves
can lead to blood clots
how can lifestyle and medical risk factors increase the chance of developing coronary heart disease (6)
poor diet and lack of exercise
leads to high blood pressure which increases cholesterol and fatty deposits
smoking > high blood pressure
genetic factors
what causes cancer
cancer is caused by uncontrolled cell growth and division resulting in the formation of a tumour
what are the two types of tumours
benign and malignant
describe benign tumours
- tumours grow until there is no room
- stays in one place (usually within a membrane)
- doesn’t invade other tissues
- not dangerous/cancerous
describe malignant tumours
(5 points )
- tumour grows
- spreads to neighbouring tissues
- cells spread via bloodstream
- invade healthy tissue to form secondary tumours
- dangerous and cancerous
name four cancer risk factors
- smoking
- obesity
- UV exposure
- viral infections
how do you test for sugars
- add benedict’s solution
- boil
- if glucose is present, colour changes to yellow/ green/ orange/ brick red
explain how amylase breaks down starch
- starch / substrate binds to active site
- because shape of active site and substrate are complementary
- chemical reaction occurs for produce sugars
how do you test milk for sugars
add benedict’s reagent to milk and boil, solution will turn from blue to brick red if positive.
how do you test milk for proteins
add biurets solution to milk and if protein is present it will go from blue to lilac
why would the ph of fat decrease when lipase is added
lipase breaks down fat into fatty acids and glycerol and fatty acids lower the pH
what does bile do to fats
bile emulsifies fats and increases the surface area so lipase can break it down quicker.
why is the heart known as a double pump?
blood is pumped to the lungs by the right side of the heart and blood is pumped to the body by the left side of the heart
what is the blood vessel that supplies the heart with glucose and oxygen ?
coronary artery
why is the left side of the heart thicker than the right side?
the left side pumps blood to the rest of the body so a higher pressure is needed. thicker muscle allows stronger contractions so more muscle
describe the process of inhalation
the ribcage moves upwards and outwards.
the diaphragm moves downwards to increase the volume in the lungs.
this decreases pressure in the lungs
the atmospheric pressure is higher than the lungs so air moves in
describe the process of exhalation
the ribcage moves down and inwards.
the diaphragm moves upwards to decrease the volume in the lungs
this increases pressure in the lungs
the atmospheric pressure is lower than in the lungs so air moves out
what is the effect of the phloem being damaged?
less sugars are transported to parts of the plant which means that less glucose is available for respiration to release energy for growth
what is the effect of the xylem being damaged?
- less absorption of water which is needed for photosynthesis so less glucose produced so less respiration takes place to release energy
- less cellulose is produced which is needed for cell walls to provide strength and support.
- less absorption of mineral ions such as nitrate ions means less proteins are made for growth
how is the small intestine adapted for efficient absorption (5)
- very long: increasing time for absorption
- villi: larger surface area
- many mitochondria: release energy from respiration for active transport
- good blood supply: maintain concentration gradient
define a double circulatory system
- blood is pumped to the lungs by the right side of the heart AND
- blood is pumped to the body by the left side of the heart
why is having one ventricle less efficient than two?
oxygenated blood and deoxygenated blood mix so less oxygen reaches the body cells
what can cause death when there is a lack of oxygen?
less aerobic respiration occurs
so less energy is released
so less metabolism
OR
anaerobic respiration occurs producing lactic acid which is toxic
why is an axolotl a suitable for animal for research?
easy to breed / reproduce quickly
- easy to keep as they are small
why does less glucose absorbed into the blood stream lead to weight loss?
less glucose is available for respiration
so more fat is used up in metabolism/ respiration
why does fewer amino acids being absorbed into the bloodstream lead to weight loss?
fewer amino acids available for making new proteins for repair
why does fewer fatty acids being absorbed into the blood stream lead to weight loss?
fewer fatty acids available and less fat stored in the body
