Functions of the Blood Flashcards
What are the four main components of blood?
- Plasma
- Platelets
- Red Blood Cells
- White Blood Cells
What is plasma?
Pale yellow liquid which carries everything needed to transport around body
Made of mainly water
What does plasma carry?
- Red and white blood cells, and platelets
- Digested food products - from gut to body cells
- CO2 - from body cells to lungs
- Urea - from liver to kidneys
- Hormones
- Heat energy
What do red blood cells do?
carry oxygen from lungs to all around the body
How are red blood cells adapted to carry oxygen?
- They are Biconcave - to give large surface area for absorbing and releasing oxygen
- They contain haemoglobin
- They do not have a nucleus - frees up space for more haemoglobin, so can carry more oxygen
Name two types of white blood cell
Phagocytes
Lymphocytes
What are pathogens?
Micro-organisms that cause disease
What do phagocytes do?
Engulf pathogens and digest them
What do pathogens have on their surface?
unique molecules called antigens
What do lymphocytes produce when they detect a foreign antigen?
Produce proteins called antibodies
These lock on to invading pathogens and mark them out for destruction by other white blood cells
Some lymphocytes stay around in the blood as…
memory cells - can reproduce very quickly if same antigen enters body a second time
What are the three types of blood vessel?
Arteries
Capillaries
Veins
What do arteries do?
carry blood AWAY from the heart
What do capillaries do?
-involved in the exchange of materials at the tissues
carry the blood really close to every cell in the body to exchange substances with them
What do veins do?
carry blood TO heart
Why are artery walls strong and elastic?
Because the heart pumps out blood at a high pressure
What is the largest arty in the body?
The aorta
How big are capillaries?
Really small
Why do capillaries have permeable walls?
So substances can diffuse in and out
What do capillaries supply and take away?
- supply food and oxygen
- take away wastes i.e CO2
How thick are capillaries walls?
one cell thick - increases rate of diffusion
What do capillaries join ip to form?
veins
Why aren’t the vein walls as thick as artery walls?
The blood is at a lower pressure
What do veins have to keep the blood flowing in the right direction?
valves
What is the largest vein in the human body?
The vena cava
What does the right atrium of the heart receive?
deoxygenated blood (through the vena cava)
After deoxygenated blood moves through the right atrium where does it go?
To the right ventricle, which pumps it to the lungs via the pulmonary artery
What does the left atrium of the heart receive?
oxygenated blood from the lungs (through the pulmonary vein)
After oxygenated blood moves through the left atrium where does it go?
The left ventricle, which pumps it round the whole body
Why does the left ventricle of the heart have a much thicker wall than the right ventricle?
Because it needs to pump blood around the whole body, whereas the right ventricle only has to pump blood to the lungs
What is the point in the valves in the heart?
They prevent the back flow of blood
Exercise increases…
Heart Rate
Why does exercise increase heart rate?
Because your muscles need more energy, so you respire more
How does your heart rate increase?
- Exercise increases the amount of carbon dioxide in the blood
- High levels of blood CO2 are detected by receptors in the aorta and carotid artery
- These receptors send signals to the brain
- The brain sends signals to the heart, causing it to contract more frequently and with more force
What else helps control heart rate?
The hormonal system
What happens when an organism is threatened?
Adrenal glands release adrenaline, adrenaline binds to specific receptors in the heart, causes the cardiac muscle to contract more frequently + with more force - so heart rate increases
This increases oxygen supply to the tissues, getting the body ready for action
What is the circulation system made up of?
The heart and the blood vessels
Normally arteries carry…
oxygenated blood
Normally veins carry…
deoxygenated blood
PULMONARY means to do with…
the lungs
HEPATIC means to do with…
the liver
RENAL means to do with…
the kidneys
What are exemptions to the rule that arteries carry oxygenated blood and veins carry deoxygenated blood?
The pulmonary artery and pulmonary vein
What is the beating of the heart controlled by?
The pacemaker region of the heart
When the chambers of the heart contract and force blood out into the arteries the heart is in…
systole
When the chambers of the heart relax and fills, is is in…
diastole
What organ is part of the urinary system?
The kidneys
What are the kidneys 3 main roles?
- removal of urea from the blood
- adjustment of salt levels in the blood
- adjustment of water content of the blood
How does the kidneys perform their 3 main roles?
By filtering stuff out of the blood under high pressure, and then reabsorbing the useful things
What is the end product of the kidneys role?
Urine
What are nephrons?
filtration units in the kidneys
Each kidney contains thousands of….
nephrons
What are the three processes of nephrons?
ultrafiltration
reabsorption
release of wastes
What is ultrafiltration?
When blood from the renal artery flows through the glomerulus, a high pressure is built up which squeezes water, urea, salts and glucose out of the blood and into the Bowman’s capsule
What is the filtered liquid in the Bowman’s capsule known as?
the glomerular filtrate
What do the membranes between the blood vessels in the glomerulus and the bowman’s capsule act as?
filters, so big molecules like proteins and blood cells are not squeezed out
What is reabsorption?
When substances are selectively reabsorbed back into the blood
- all the glucose is reabsorbed from the proximal convoluted tubule (use of active transport)
- sufficient salt is reabsorbed
- sufficient water is reabsorbed from the collecting duct into the bloodstream
What is the release of wastes?
Where the remaining substances (including water, salts, and urea) form urine
This continues out of the nephron through the ureter and down the bladder, where it is stored before being released via the urethra
What is the balancing of water and salts called?
osmoregulation
What is reabsorption of water controlled by?
ADH
changes the permeability of the collecting ducts in nephrons
What is urine made from?
Water, urea and salts
What is the urinary system made up of?
the kidneys, ureters, bladder and urethra
How is water lost from the body
sweating
breathing
weeing
What is osmoregulation ?
The balance of water levels
List the process that happens when your dehydrated
- Brain detects water loss
- Pituitary gland releases more ADH
- ADH makes kidney reabsorb more water
List the process that happens when your hydrated
- Brain detects water gain
- Pituitary gland releases less ADH
- Lack of ADH means kidneys reabsorb less water
what happens when you damage a blood vessel?
platelets clump together to block up the damaged area - this is known as blood clotting
why are blood clots important?
to stop you losing too much blood and prevent microorganisms from entering the wound
in a blood clot, what are platelets held together by?
a mesh of a protein called fibrin (this process also needs other proteins called clotting factors to work)
what does vaccination involve?
injecting dead or inactive pathogens into the body.
how and why will lymphocytes react to a vaccination?
The dead or inactive pathogens carry antigens so even though they’re harmless they still trigger an immune response - your immune system will produce antibodies to attack them
thanks to a vaccination, what will happen if live pathogens of the same type ever appear?
the antibodies to kill them will be produced much faster and in greater numbers thanks to lymphocyte memory cells
