Organisation - the circulatory system Flashcards
where are the lungs
in the thorax ( top part of your body ) and are protected by the ribcage
how does air travel through the lungs
- goes in through the trachea ( windpipe )
- this splits into two tubes called bronchi
- these then split into smaller tubes called bronchioles
- the bronchioles finally end at small bags called alveoli where the gas exchange takes place
what are alveoli
little air sacs that carry out gas exchange
describe gas exchange
1 -blood returns to body from lungs with a lot of co2 and not much o2
2- oxygen diffuses out the alveolus ( high conc) into the blood ( low conc ) then co2 diffuses out of the blood and into the alveolius to be breathed out
3- when the blood reaches body cells, oxygen is released from the red blood cells ( high conc ) and diffuses into the body cells ( low conc )
4 - at the same time, carbon dioxide diffuses out of body cells ( high conc ) into the blood ( where theres low conc ) , its then carried back to lungs
what happens in the first circuit of the double circulatory system
the right ventricle pumps deoxygenated blood to the lungs to take in oxygen, the blood then returns to the heart
what happens in the second circuit of the double circulatory system
the left ventricle pumps oxygenated blood around all the other organs of the body
- the blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again
what does the heart do
contracts to pump blood around the body
what is the heart
a pumping organ that keeps blood flowing around the body, walls mostly made of muscle tissue
why does the heart have valves
to make sure blood flows in the right direction
- prevents it from flowing backwards
how many chambers are in the heart
4
what are the hearts chambers
right atrium, right ventricle, left atrium, left ventricle
what parts of the heart are on the right side
right atrium, right ventricle, vena cava, pulmonary artery
what parts of the heart are on the left side
aorta, pulmonary vein, left atrium, left ventricle
how does blood go around the BODY
1 - the vena cava brings in deoxygenated blood from the body
2. the blood then passes from the heart to the lungs in the pulmonary artery
- in the lungs, the blood collects oxygen
- oxygenated blood passes from the lungs to the heart in the pulmonary vein
- Oxygenated blood is pumped from the heart to the body in the aorta
what are coronary arteries
supply heart with oxygen
what is a pacemaker
- a group of cells in the right atrium wall that control resting heart rate
what is an artificial pacemaker
- a small device that’s placed (implanted) in the chest to help control the heartbeat
three types of blood vessels
- arteries
- capillaries
- veins
what do arteries do
carry blood away from the heart and into organs in the body
what do capillaries do
they carry blood close to every cell to exchange substances with them
what do veins do
carry blood to the heart
how are arteries designed for their job
- job is to carry blood away from the heart
- heart pumps blood at high pressure, so artery walls are strong and thick
- walls are thick compared to size of hole down the middle ( lumen )
- contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back
how are capillaries designed for their job
- job is to exchange materials
- very tiny
- permeable walls so substances can diffuse in and out
- supply food and oxygen and take away waste like CO2
- walls are usually one cell thick, (thin) increases rate of diffusion by decreasing the distance over which it occurs
how are veins designed for their job
- job is to carry blood to the heart
- blood is at lower pressure in veins so walls aren’t as thick as arteries
- bigger lumen to help blood flow despite the lower pressure
- have valves to keep blood flowing in right direction
what sides of the heart carry what type of blood
right carry deoxygenated blood, left carries oxygenated
what does the pulmonary vein do
transports oxygenated blood from the lungs to the heart
what does the pulmonary artery do
transports de-oxygenated blood from the heart to the lungs
what does the vena cava do
The heart receives deoxygenated blood from the body through a vein called the vena cava.
what does the aorta do
pumps out oxygenated blood to the body
job and specialisations of red blood cells
- job is to carry oxygen from the lungs to all body cells
- large surface area for absorbing oxygen
- haemoglobin for red pigment, which binds to oxygen to form oxyhemoglobin, and is released to body cells
- biconcave shape to give them a higher surface to volume ratio to improve diffusion
- no nucleus so it has more space for haemoglobin
job and specialisations of white blood cells
- job is to defend against infection
- can change shape to capture unwelcome microorganisms
- produce antibodies to fight microorganisms
- have a nucleus which contains DNA which encodes the instructions that the WBCs need to do their job
- release abtitoxins
what are platelets
small fragments of cells with no nucleus, responsible for blood clotting
what do platelets do
- help blood clot at a wound to stop all your blood pouring out and to prevent microorganisms from getting in
- lack of platelets can cause excessive bleeding and bruising
what is plasma
- liquid that carries dissolved substances in blood - red blood cells , white blood cells and platelets
- also carry nutrients like glucose, amino acids
- also carry CO2. Urea
what is haemoglobin and what does it do
- found in red blood cells. -
- binds with oxygen in the lungs.
- carries oxygen which will then be released to the body cells to be used for respiration.
explain how the human circulatory system is adapted to
- supply oxygen to the tissues
- remove waste products from tissues
- blood goes back to the heart via veins which have valves to prevent backflow
- humans have a double circulatory system, which increases blood pressure and flow of blood to the tissues
- Oxygen is then carried around the body by red blood cells. They are specialized cells, which have no nucleus and contain haemoglobin so that there is maximum space for oxygen
- capillaries have a large surface area to maximise exchange
- capillaries have thin walls making it easier to diffuse to cells
- waste products removed such as co2 , it diffuses from cells into blood plasma
- Capillaries cover 70% of the outside of alveoli, providing a large surface area for gases to diffuse across.
- capillaries are once cell thick to shorten diffusion path
explain why having one ventricle makes the circulatory system less efficient than having 2
- deoxygenated blood and oxygenated blood will mix and this means less oxygen will reach the body
what is a problem with a single circulatory system in fish
- the blood loses a lot of pressure as it passes through the gills before reaching the organs
- this means that blood travels to the organs relatively slowly so it cant deliver a lot of oxygen
what is a double circulatory system
- where the blood passes through the heart twice per circuit
- deoxygenated passes through the heart to the lungs where it collects oxygen
- oxygenated blood then returns to the heart
- heart then pumps oxygenated blood to other organs in the body
what is a benefit of the double circulatory system
because the blood passes through the heart twice, it can travel rapidly to the body cells, delivering the oxygen that the cells need
what does the vena cava do
brings in deoxygenated blood from the body
what is the pattern of blood flow around the heart
- blood enters the left atrium then the right atrium
- atria contract and blood is forced into the ventricles
- the ventricles contract and force blood out of the heart
- valves in the heart stop blood from flowing backwards into the atria when the ventricles contract
why does the left side of the heart have a thicker muscular wall than the right side
because left side pumps blood around the whole body, so it will need to provide a greater force, right side only pumps blood to the lungs
how can donated blood be used in medicine
- to replace blood lost during injury
- some people are given platelets extracted from blood to help in clotting
- proteins extracted from blood can also be useful, for example antibodies
what are some problems with using donated blood
- in blood transfusion, we have to make sure that the donated blood is the same blood type as the patients
- otherwise the bodies immune system will reject the blood and the patient could die - Lots of different diseases can be transmitted via blood
- in the uk, blood is screened for infections so risk is very low
