B4 Flashcards
4 components of the blood
plasma, red blood cells, white blood cells, platelets
function of red blood cells
Transport oxygen around the body
function of platelets
blood clotting at a wound
Function of plasma
It carries many substances dissolved in it including glucose for body cells
Function of white blood cells
defend the body against infectious organisms
adaptation of red blood cells
Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus, so the whole cell is full of haemoglobin.
What allows red blood cells to carry oxygen?
haemoglobin
What does plasma contain?
Hormones, antibodies, nutrients, waste substances
Name of process of white blood cells engulfing bacteria
Phagocytosis
product of oxygen and haemoglobin
oxyhaemoglobin
Name the 3 blood vessels
arteries, veins, capillaries
Function of arteries
carry blood away from the heart
Adaptations of arteries
small lumen - pressure and flow is high
thick walls - withstand high pressure
elastic tissue - allows blood vessels to stretch and recoil to smooth blood flow
What type of blood does arteries carry
oxygenated blood
function of veins
carry blood back to the heart
Adaptation of veins
Wide lumen - keeps blood flowing smoothly, at a low pressure
Valves prevent back flow of blood
Thin outer wall - muscles can squeeze vein: keeps blood moving up the body
What type of blood do veins carry?
deoxygenated blood
What do veins contain?
valves
function of valves
prevent back flow of blood
function of capillaries
to exchange of materials such as oxygen & carbon dioxide between the blood and body cells.
Adaptation of alveoli
- millions of tiny capillaries (large surface area)
- thin wall/one cell thick (short diffusion distance)
- narrow lumen (increases diffusion time, decreases diffusion distance)
- circulation maintains concentration gradient (low oxygen, high carbon dioxide)
What do capillaries link?
arteries and veins
What does double circulatory system mean?
The heart pumps blood around the body in two circuits.
4 chambers of the heart
Right atrium, right ventricle, left atrium, left ventricle
Name of the vein where blood into the heart
Vena Cava
In which chamber does deoxygenated blood enter the heart?
Right Atrium
Name the artery that carries deoxygenated blood to the lungs
Pulmonary Artery
Name the vein that carries oxygenated blood back to the heart
Pulmonary Vein
Which chamber pumps blood around the body?
Left ventricle
adaptation of the left ventricle
thick muscular wall
which chamber in the heart has the highest blood pressue
Left ventricle
Name the artery that carries blood away from the heart to the rest of the body
Aorta
Advantages of an artificial heart
Keep people alive while they wait for a transplant, less likely to be rejected
Disadvantages of an artificial heart
Surgery to fit it can lead to bleeding and infection
Blood doesn’t flow as smoothly - can cause blood clots, leading to strokes
Has to take drugs to thin blood to make sure this doesn’t happen
What is a pacemaker?
A group of cells in the right atrium wall that control the resting heart rate
They produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract
Artificial pacemakers can be used to control heartbeat if the natural pacemaker cells don’t work well e.g. irregular heartbeat
What are stents?
Tubes that are inserted into arteries to keep them open, making sure blood can pass through
where are the lungs found?
upper part of the chest - thorax
What protects the lungs?
ribcage
function of diaphragm
separates the lungs from the digestive organs - abdomen
Inhalation
breathing air into the lungs - the diaphragm contracts and pulls downward
Exhalation
breathing air out of the lungs - the diaphragm and the intercostal muscles relax, forcing air out of the lungs.
Where does gas exchange occur?
alveoli in the lungs
What are alveoli?
tiny air sacs in the lungs
Adaptation of alveoli for gas exchange
The alveoli have are thin, this allows gasses to diffuse through them easily.
They are small and there are many of them meaning there is a large surface area through which much gas can diffuse at once. It also means there is a lot of surface in contact with the blood stream for gasses to diffuse into.
Alveoli have a moist lining for gasses to dissolve into.
By which exchange process is oxygen transported into the blood?
Diffusion - oxygen enters and carbon dioxide leaves the blood
Name 2 vascular tissues in plants
Xylem and Phloem
What is xylem made of?
dead cells
What does xylem transport?
water and minerals ions
What direction do xylem items move?
One direction - roots to leaves
Adaptations of xylem
Cells join together to form long hollow tubes that allow water and mineral ions to move easily through them
Spirals and rings of lignin in cells make them very strong and help them withstand the pressure of water moving
What is phloem made of?
living cells
What does phloem transport?
sugars
Adaptation of phloem
Sieve tubes - specialised for transport and have no nuclei
What direction do phloem items move?
Bi - directional - all over the plant
What process are phloem vessels involved in?
Translocation
What is translocation in a plant?
the movement of food substances from the stems to growing tissues and storage tissues.
What are stomata?
small openings on the underside of a leaf through which oxygen and carbon dioxide can be diffused
What opens and closes the stomata?
guard cells
Function of waxy cuticle
to prevent/reduce water loss and prevent entry of microorganisms
Function of epidermal tissue
Covers the whole plant and protects it
Function of palisade mesophyll
The main site of photosynthesis in the leaf - contains chloroplasts for photosynthesis
Function of spongy mesophyll
Contains air spaces between the cells to allow gases to diffuse through the leaf.
Process of water loss through leaves
Transpiration
Describe the process of transpiration
- Water is lost through the leaf by evaporation
- Water moves into the roots via osmosis
- Water is drawn up and moves up the stem to replace the lost water
Factors affecting rate of transpiration
- Temperature
- Humidity
- Light intensity
- Wind
How light intensity affects transpiration
An increased light intensity would increase the rate of photosynthesis.
The stomata will be open to increase the rate at which carbon dioxide
enters and therefore more water will be lost from the leaves due to
evaporation; therefore increasing the rate of transpiration
How humidity affects transpiration
If the air around a leaf has a low concentration of water molecules (less
humid, dry conditions). The concentration gradient between water
molecules in the leaf and the surrounding air will be quite steep.
Therefore, water molecules will evaporate from the surface off the leaf
more readily, increasing the rate of transpiration
How does temperature affect transpiration
An increase in temperature will mean that molecules move more rapidly,
this would cause more water molecules to evaporate from the surface of
the leaf and an increase in transpiration. A temperature increase would
also cause the rate of photosynthesis to increase, this means the stomata
are open for gas exchange and so more water will leave the surface of the
leaf, once again increasing the rate of transpiration
How does wind affect transpiration?
If a plant is in windy conditions it will mean that there will be an increase
in the rate of evaporation from the surface of the leaf as water molecules
will be taken away more easily, this will increase the rate of transpiration.
