B4 - organising animals and plants fact test Flashcards
what is the blood
it’s a tissue
its main components are red and white blood cells, platelets and plasma
how are red blood cells specialised
- no nucleus, making space for haemoglobin
- packed with a red pigment called haemoglobin that binds to oxygen, so it moves from lungs to tissues
- biconcave discs (pushed in on both sides) to increase surface area to volume ratio for diffusion
what are white blood cells
- much larger than red blood cells
- there are fewer of them and they have no nucleus
- they form part of the body’s defence system against harmful microorganisms
- lymphocytes form antibodies against microorganisms
- some form antitoxins against poisons made by microorganisms
- phagocytes engulf and digest bacteria and viruses
what are platelets
- small fragments of cells
- have no nucleus
- help the blood clot and form a scab at the site of a wound
- stops you bleeding to death
- stops bacteria entering the body through the wound
what is plasma
- yellow liquid
- transfers all of your blood cells around the body
- transports waste carbon dioxide, urea, glucose around the body
- DO NOT CARRY OXYGEN
what are arteries and how are they specialised
- thick layer of muscle and elastic fibres
- small lumen
- thick walls
- arteries carry blood away from the heart to other organs
- the blood came from the heart so it’s under pressure
- the elastic allows the vessel to stretch without bursting
- lots of muscle to prevent rupture
- usually oxygenated blood
what are veins and how are they specialised
- have a valve and large lumen
- relatively thin walls
- thin layer of muscle and elastic fibres
- carry blood towards heart (so less pressure)
- valves which open and close to prevent the backflow of blood
thinner walls to prevent the backflow of blood - usually low in oxygen
what are capillaries and how are they specialised
- walls are one cell thick
- tiny vessel with a narrow lumen
- tiny vessels linking veins and arteries
- walls are one cell thick to allow substances to diffuse in and out
where does blood from the aorta go
heart to rest of the body
where does blood from the vena cava go
from body to heart
where does blood from the pulmonary artery go
heart to lungs
where does blood from the pulmonary vein go
lungs to heart
why is the muscle on the left side thicker than the muscle on the right side
the blood needs to be pumped further so it has a higher pressure, the muscle prevents rupture
where are pacemakers
a group of cells in the right atrium and they control the resting heart rate
what are coronary arteries
branch off the aorta and supply the heart muscle with glucose and oxygen which are needed for respiration to release energy
what are cardiovascular diseases
diseases of the heart of blood vessels
how do you treat coronary heart disease (coronary arteries becoming blocked by fatty deposits
- stents can be fitted in narrow arteries to increase bloodflow through them
- statins reduce the risk of fatty plaques breaking off from walls of your arteries
how do you treat heart failure
- heart transplant
- mechanical artificial heart whilst waiting for a donor
how do you treat damaged heart valves as they can break or not open properly
- biological heart valves
- mechanical heart valves
how do you treat an irregular heart rate
get an artificial pacemaker fitted
what does the trachea do
carries oxygen in and carbon dioxide out
what do the intercostal muscles do
move the ribs up and out to provide surface area
what do the alveoli do
where gas exchange happens
what does the diaphragm do
contracts and relaxes allowing a change in surface area / volume
what are leaves
organs that work with the roots and stems in an organ system to transport substances
what does the upper epidermis do
produces a waxy cuticle
what does the lower epidermis do
has pores called stomata to enable gas exchange
what do epidermal tissues do
cover the surfaces of the leaf
what do guard cells do
specialised to control the opening and the closing of the stomata
what does the palisade mesophyll do
contains palisade cells. it is adapted to absorb as much light as possible as it is the sight of photosynthesis
what does the spongy mesophyll do
has air spaces to create large surface area for gas exchange
what are the xylem and phloem
major transport tissues in plants, they are often found together in vascular bundles (the veins you can see in leaves)
what is meristem tissue
it’s found at the tips of growing regions of plants and can differentiate into different types of plant cell
what does the xylem do
transports water and dissolved mineral ions up from the roots to the leaves
what is transpiration
transpiration is the loss of water from plants by evaporation from the leaves
how does light affect the rate of transpiration
the lighter it is, the more transpiration occurs as the stomata have to allow carbon dioxide in and water out
how does wind affect the rate of transpiration
more wind means the higher the concentration gradient because water is being carried away
how does humidity affect the rate of transpiration
more humid conditions mean less transpiration because less of a concentration gradient as there’s lots of water in the air
how does temperature affect the rate of transpiration
the higher the temperature, the higher the transpiration due to transfer of kinetic energy
why are some plants adapted with leaves reduced to spines
reduces surface area for transpiration
why are some plants adapted to have a reduced number of stomata
reduces the rate of transpiration
why do plants have a waxy leaf cuticle
impermeable to water which stops evaporation
why are some plants adapted to have rolled leaves, leaf hairs and stomata sunk in pits
traps moist air which increases humidity and reduces the diffusion of water vapour
what does the phloem do
transports sugars and amino acids
what is translocation
translocation is the movement of sugars and amino acids in all directions from the leaves to where they are needed in the plant
what is a potometer
an instrument used to measure the rate of transpiration in plants
how is a potometer used
- there is a bubble in the capillary tube
- a ruler is used to measure the distance the bubble moves
- the further the bubble moves, the higher the rate of transpiration, and the less distance the bubble moves, the lower the rate of transpiration
