B4 - Organising animals and plants Flashcards
What are the three components of the human circulatory system
- blood
- blood vessels
- heart
What are the 4 main parts of the blood
- platelets
- plasma
- red blood cells
- while blood cells
What is the role of the plasma
transports blood cells around the body
- carries dissolved substances such as urea, carbon dioxide and small products of digestion
What are three adaptations of the red blood cell to help them carry oxygen
- biconcave disc provides large surface area
- lots of haemoglobin which carries oxygen
- no nucleus to make space for more haemoglobin
What proportion of the blood is each component
- 45% red blood cells
- 55% plasma
1% platelets and white blood cells
What are the functions of white blood cells
phagocytes engulf pathogens
- lymphocytes form antibodies and antitoxins
What are platelets
small fragments of cells that cause blood clotting
What are the three blood vessels and what are their functions
arteries carry blood away from the heart
veins carry blood towards the heart
capillaries link arteries and veins, and it is where the substances diffuse into and out of cells
How are arteries adapted for carrying blood
thick, muscular walls for high pressure blood
How are veins adapted for carrying blood
valves prevent backflow and blockages
How are capillaries adapted for carrying blood
single cell thick walls for short diffusion distances
How do muscles force blood towards the heart in veins
they contract, squeezing the blood vessels and blood towards the heart
What does each circulatory system do in the human double circulatory system
one transports blood from heart to lungs and back again. This allows carbon dioxide and oxygen to diffuse in and out the body
one carries blood from heart to organs and back again
why is having a double circulatory system good
it makes it very efficient
what are the walls of the heart mostly made of
muscle
what are coronary arteries
arteries that supply blood to the heart muscles
What are the top chambers of the heart called
atria
What are the bottom chambers of the heart called
ventricles
how does the blood enter and leave the heart
vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta
what does the pulmonary artery do
take blood from heart to lungs
What does the pulmonary vein do
carry blood from lungs to heart
what are valves in the heart used for
making sure blood flows in the right direction
what actually is the heartbeat
the sound of valves closing
why is the muscle wall of the left ventricle thicker than the right
to develop the high pressure needed to force the blood through the arteries
What happens in coronary heart disease
- what is a common cause of this
- what is the effect
the coronary arteries become narrow
- buildup of fatty material on the lining of the vessels
- less oxygen is supplies to heart muscles causing pain, heart attacks or even death
What are three common treatments to coronary heart disease
stents
statins
replacement arteries
how are stents inserted in the arteries
a tiny balloon is inflated to open the blood vessel and stent
balloon is deflated but stent remains, holding the artery open
How do statins work
they are drugs that reduce blood cholesterol levels, slowing down the rate at which fatty material is deposited in the coronary arteries
what are two common treatments of leaky valves
- what are the negatives of each
mechanical valves require users to take medicines for their whole life
biological valves only work for around 12-15 years
how are problems with the natural pacemaker solved
- what does it do
by fitting an artificial pacemaker
- it sends electrical signals that stimulate the heart to beat properly
why do many people die before getting a necessary heart transplant
they have to wait for a donor with a tissue match
what is an alternative to donor hearts
- what are some negatives
artificial hearts
- very expensive
- can cause blood clotting
- patients usually have to stay in hospital
what happens when you breathe in
ribs move out, diaphragm flattens: more volume so air is drawn in to maintain pressure
What happens when you breathe out
ribs move in, diaphragm moves up: less volume so air moves out to maintain pressure
how does the volume of the lungs change
when intercostal muscles between ribs and diaphragm move
how is a concentration gradient maintained in the lungs
oxygenated air is drawn in, blood flows bringing deoxygenated blood
how are the lungs adapted for gas diffusion (6)
- alveoli increase surface area
- rich supply of capillaries
- thin walls
- spherical shape gives largest surface area
- well venilated
- moist walls
What do epidermal tissues do in plants
cover surfaces and protect them. They often secrete a waxy substance that waterproofs the leaf
What is palisade mesophyll
tissue with lots of chloroplasts for photosynthesis
What is spongy mesophyll
tissue with some chloroplasts but lots of air and surface area to make diffusion of gases easier
What are xylem
tissue that transports water and mineral ions from the roots to the plant via transpiration
what are phloem
tissue that transports food from the leaves to the plants via translocation
where are stem cells in the plant
in the meristem tissue at the growing tips of roots and shoots
what are some examples of organs in plants
leaves, roots, stem
how are xylem tissue adapted
dead cells make tubes hollow, lignin strengthens the tube
why is transport so important for plants
- cells need glucose for respiration
- cells need water for photosynthesis
- mineral ions are needed for protein synthesis
what are stomata
- what are their sizes controlled by
openings in the leaf
- guard cells
why do plants have stomata
to control rates of diffusion of carbon dioxide and oxygen
what is transpiration
the loss of water vapour through the stomata
what is the transpiration stream
water drawn through xylem from roots to leaves due to the water lost through stomata
how can you calculate the amount of stomata in a leaf
make a stomatal peel using varnish to get a thin layer
- place on a microscope slide
- adjust to a higher magnification
- count the number of stomata in the visible area
- repeat all over the leaf and calculate the average
- use this to estimate total amount in leaf
what are three factors that increase rate of transpiration
hot, dry, windy conditions
what is the function of the waxy cuticle on water loss
prevents lots of water loss
what are two ways plants reduce rate of transpiration
wilting decreases the surface area
- stomata close
how are potometers used to measure transpiration rate
measure amount of water taken in in a given time. Most of this water is lost in transpiration
