❤️🔥2- transport Flashcards
where does the exchange of substances occur
across the cell membrane
unicellular organisms have
very large surface areas in comparison to their volumes this means that the distance between the surface of the organism to its centre is very small
unicellular organisms do not need to have
specialist exchange surfaces or transports systems as processes such as diffusion, osmosis and active transport through the cell membrane occur at a sufficient rate to meet the organisms needs
large multicellular organisms like humans have
relatively small surface areas in comparison to their volumes so the distance between the surface of the organism to its centre is relatively long
exchange surfaces in animals include
the lungs and alveoli for gas exchange, the small intestine and villi for absorption of digested foods
transport systems in animals include
the blood and circulatory systems carries the necessary substances around the body
exchange surfaces in plants include
roots and root hairs where mineral ions and water are absorbed, the leaves for gas exchange
transports systems in plants include
the xylem moves water and mineral ions from roots to shoots, the phloem moves sugars and amino acids to where they are needed in the plant
the roots, stem and leaves form a
plant organ system for the transport of substances around the plant
plants also possess
two specialist transport vessels called the xylem and phloem
the xylem and phloem are arranged
throughout the root, stem and leaves in groups called vascular bundles
xylem vessels transport
water and minerals from the roots to the stem and leaves
xylem key structural features
-it is composed of dead cells which form hollow tubes, xylem cells are strengthened by lignin and so are adapted for the transport of water in the transpiration system
phloem vessels transport
food materials (mainly sucrose and amino acids) made by the plant from photosynthesising leaves to non photosynthesising regions in the roots and stem, this means that they can be in any direction around the plant
phloem key structural features
the cells are living cells and not hollow, substances move from cell to cell through pores in the end walls of each cell
blood consists of
red blood cells, white blood cells, platelets and plasma
over half the volume of blood consists of
plasma
the majority of the other half of blood consists of
red blood cells
a small fraction of blood consists of
white blood cells and platelets
red blood cells
biconcave discs containing no nucleus but plenty of the protein haemoglobin
white blood cells
large cells containing a big nucleus, different types have slightly different structures and functions
platelets
fragments of cells
plasma
straw coloured liquid
red blood cells are
specialised cells which carry oxygen to respiring cells
red blood cells are adapted to function in 3 key ways-
they are full of haemoglobin a protein that binds to oxygen to form oxyhemoglobin, they have no nucleus which allows more space for haemoglobin to be packed in, the shape of the red blood cell is described as a biconcave disk- this gives them a large surface area to volume ratio to maximise diffusion of oxygen in ad out
plasma is
a straw coloured liquid with other components of blood are suspended within
plasma is important for
the transport of many substances
substances plasma transports
carbon dioxide- the waste product of respiration, dissolved in the plasma as hydro carbonate ions and transported from respiring cells to the lungs
digested food and mineral ions- dissolved particles absorbed from the small intestine and delivered to requiring cells around the body
urea- the waste substance produced in the breakdown of proteins by the liver. urea is dissolved in the plasma and transported to the kidneys
hormones- chemical messengers released into blood from endocrine organs and delivered to target tissues/organs of the body
heat energy- created in respiration, heat energy is transferred to the coolest parts of the body or skin where heat can her lost
white blood cells are part of the bodies
immune system
types of white blood cell
phagocytes, lymphocytes
phagocytes carry out
phagocytosis by engulfing and digesting pathogens
phagocytes have
a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells. once they encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest it
lymphocytes produce
antibodies
antibodies are
Y shaped proteins with a shape that is complementary to the antigens on the surface of the pathogen. this is a specific type of immune response as the antibodies will only fit one type of antigen on a pathogen
antibodies attach
to the antigens and cause agglutination, this means pathogenic cells can’t move very easily and at the same time chemicals are released that signal to phagocytes that are cell present that need to be destroyed
lymphocytes also produce
antitoxins to neutralise toxins released by pathogens
an organism has immunity when they
have sufficient levels of antibodies to protect it from a particular disease and as a result don’t suffer from the disease or its symptoms
response to infection
1) the pathogen enters the blood stream and multiplies
2) a release of toxins and infection of body cells causes symptoms in the patient
3) phagocytes that encounter the pathogen recognise that it is an invading pathogen and engulf and digest
4) eventually the pathogen encounters a lymphocyte which recognises its pathogens
5) the lymphocyte starts to produce specific antibodies to combat that particular pathogen
6) the lymphocyte also clones itself to produce lots of lymphocytes (all producing the specific antibody required)
7) antibodies cause agglutination of pathogens
8) phagocytes engulf and digest the agglutinated pathogens
9) after the patient has recovered they retain antibodies specific to the disease as well as memory cells
10) if the patient encounters the same pathogen again it will trigger the secondary immune response
11) memory cells can produce much larger quantities of that required antibody in a much shorter time to fight off the pathogen before the patient suffers any symptoms
the heart organ is a
double pump
oxygenated blood from the lungs enter
the left side of the heart and is pumped to the rest of the body (systemic circuit)
the left ventricle has a
thicker muscle wall than the right ventricle because it has to pump blood at a high pressure around the whole body
deoxygenated blood from the body enters
the right side of the heart and is pumped to the lungs (pulmonary circuit)
the right ventricle
pumps blood at a lower pressure to the lungs
a muscle wall called the
septum separates the two sides of the heart
blood is pumped towards
the heart in veins and away from the heart in arteries
the coronary arteries supply
the cardiac muscle tissue od the heart with deoxygenated blood
as the heart is a Muscle it needs a
constant supply of oxygen and glucose for aerobic respiration to release energy to allow continued muscle contraction
valves are present to
prevent blood flowing backwards
the pathway of blood to the heart
deoxygenated blood coming from the body flows through the vena cava and into the right atrium. the atrium contracts and the blood is forced through the tricuspid valve and into the right ventricle. the ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery. the blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place. oxygenated blood returns via the pulmonary vein to the left atrium. the atrium contracts and forces the blood through the bicuspid valve into the left ventricle. the ventricle contracts and blood is forced through the semilunar valve and out through the aorta
low pressure blood floe on the left side of the heart prevents
damage to the capillaries in the lungs
heart rate is measured by
counting the number of times a heart beats a minute
the heart pumps blood around the body in order to
supply oxygen and glucose to respiring cells
the blood removes
waste products from respiring cells
during exercise
the cells of the muscles respire more rapidly in order to provide energy for muscle contraction
an increase in respiration means
an increase in requirement for oxygen and glucose as well as an increase in production of waste products that need to be removed
the nervous system responds to an increase in respiration by
increasing heart rate to deliver oxygen and glucose and remove waste products more frequently. the volume of blood being pumped out also increases to deliver bigger quantities of oxygen and glucose
production of adrenaline
increases heart rate as part of a ‘fight or flight’ response
at the end of a period of exercise
the heart rate may remain high for a period of time as oxygen is required in the muscles to break down the lactic acid from anaerobic respiration- this is how oxygen debt is payed off
the time taken for the heart rate to return to rest is called
the recovery time
fitness affect resting heart rate
a physically fit person will have a lower resting heart rate and a shorter recovery time compared to an unfit person
cardiac muscle cells need a supply of blood to
deliver oxygen and glucose and to remove waste products such as carbon dioxide
in coronary heart disease
layers of fatty material builds up inside the coronary arteries, these fatty deposits are mainly formed of cholesterol.
sources of cholesterol in the body
dietary cholesterol and cholesterol synthesised by the liver
what if the coronary artery becomes partially or completely blocked by fatty deposits
it loses its elasticity and can’t stretch to accommodate the blood which is being forced through every time the heart contracts
the flow of blood through arteries is reduced due to fatty deposits clogging the coronary artery, which results in
a lack of oxygen for the heart muscle.
partial blockage of the coronary arteries creates
a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina
complete blockage of coronary arteries means
cells in that area of the heart will not be able to respire aerobically, leading to a heart attack
treatment of coronary heart disease
either increasing the width of the lumen of the coronary arteries using a stent or prescribing statins to lower blood cholesterol
obesity affect on coronary heart disease
carrying extra weight puts a strain on the heart and extra weight can lead to diabetes which further damages your blood vessels
high blood pressure increase of coronary heart disease
high blood pressure increases the force of blood against the artery walls and consequently leads to the damage of the vessels
high cholesterol increase of coronary heart disease
high cholesterol speeds up the build up of fatty plaques in the arteries leading to blockages
smoking increase of coronary heart disease
chemicals in smoke cause an increase in plaque build up and an increase in blood pressure. carbon monoxide also reduces the oxygen carrying capacity of the red blood cells
three main types of blood vessels
arteries, veins, capillaries
smaller vessels that branch off from arteries are called
arterioles (small arteries)
smaller vessels that branch into veins are called
venules
artery key features
carry blood at high pressure away from the heart, carry oxygenated blood, have thick muscular walls containing elastic fibres, have a narrow lumen, blood flows through at fast speed
structure of artery adapted to its function by
thick muscular walls containing elastic fibres withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through. a narrow lumen also helps to maintain high pressure
key features of veins
carry blood at low pressure towards the heart, carry deoxygenated blood, have thin walls, have a large lumen, contain valves, blood flows at a slow speed
the structure of a vein adapted to its function by
a large lumen reduces resistance to blood flow under low pressure, valves present the back flow of blood as it is under low pressure
capillaries key features
carry blood at low pressure within tissues, carry both oxygenated and deoxygenated blood, have walls that are one cell thick, have ‘leaky’ walls, speed of blood flow is slow
structure of capillary is adapted to its function by
they have walls that are on cell thick so there is a short diffusion distance, the ‘leaky walls’ allow blood plasma to leak out and form tissue fluid surrounding cells
as arteries get further away from the heart
they divide more and get narrower
the narrow vessels that connect arteries to capillaries are called
arterioles
veins get narrower the
further away they ar from the heart
the narrow walls that connect the capillaries to veins are called
venules
circulatory system blood vessels to heart
deoxygenated blood is carried away from the heart and towards organs in arteries. these narrow to arterioles and then capillaries as they pass through the organ. in the organs, respiring cells use up the oxygen from the blood, the capillaries widen to venules and finally veins as they move away from the organs. veins carry deoxygenated blood back towards the heart.
