B4 - Organising Animals and Plants Flashcards
role of the heart in the circulatory system
to pump the blood
how do valves control the direction of the blood flow in the heart
- catch blood being forced into the wrong place
- close - stopping it going the wrong way
- maintains one way flow
structure of the heart
- vena cava
- right atrium
- right ventricle
- left atrium
- left ventricle
- heart valves
- pulmonary vein
- aorta
- heart wall
vena cava
carries deoxygenated blood to the heart - to the right atrium
aorta
carries oxygenated blood around the body from the left ventricle
right atrium
deoxygenated blood
pulmonary artery
carries deoxygenated blood away from the heart towards the lungs
pulmonary vein
carries oxygenated blood away from the lungs towards the heart (into the left atrium)
how does blood move
contractions (heartbeats)
why is the left ventricle wall thicker than the right
to generate enough power to pump blood around the whole body not just the lungs like the right does
main structures of the circulatory system
- heart
- blood
- blood vessels - veins, capillaries, arteries
why do warm blooded animals need a double circulatory system
- to keep warm and maintain body temperature
- separate circulations for lungs and body
- more oxygen transported
- higher rates of respiration
arteries
- carry blood away from the heart
- thicker walls
- relatively small lumen
- carry oxygenated blood (barr pulmonary)
- not permeable
- lower CO2 concentration
- higher amino acids
- higher glucose concentration
capillaries
- carry blood between arteries and veins
- one cell thick walls
- very small lumen
- semi-permeable
veins
- carry blood towards the heart
- thinner walls
- relatively large lumen
- carry deoxygenated blood
- not permeable
- higher CO2 concentration
- lower amino acids
- higher water concentration
- higher lactic acid concentration
adaptations of the capillaries
shorter diffusion distance
for: oxygen going into the cells, glucose needed in the cells, lactic acid needed to be removed from the cells
why do we have blood
- to transport glucose and oxygen
- to protect immune system
- to regulate body temperature
structure of blood
- platelets
- phagocytes
- lymphocytes
- white blood cells
- red blood cells
- plasma - hormones, CO2, vitamins
red blood cells
- biconcave shape
- haemoglobin
- no nucleus
platelets
- clot blood
- activate enzymes to turn fibrinogen into an insoluble protein (fibrin)
- fibrin forms a net
- net traps other blood cells, clotting
magnification =
image size / actual size
white blood cells
contain phagocytes and lymphocytes
lymphocytes
- recognise specific antigens on a pathogen
- produce specific antibodies to destroy them
- produces memory cells that remain in the blood to recognise the same pathogen-antibody pairing
ACTIVE IMMUNITY - some antitoxins that counteract toxins released by pathogens
phagocytes
- engulf any pathogen they encounter
- digest them with enzymes
- destroy the pathogen and prevent disease
coronary arteries
supply blood to the heart
what causes arteries to narrow
build up of cholesterol from diet of fried food/red meat
stent
small wire tube pushed through blood vessels to the heart that inflates like a cage balloon to widen the artery
advantages of stents
- more blood - oxygen, glucose - can be supplied to the heart
- prevents angina and heart attacks
- can be done without general anaesthetic
- only a short hospital stay, if any
- costs less for the NHS than a bypass surgery
bypass surgery
vein taken from leg sewn around cholesterol affected artery
disadvantages of stents
- can’t be used in severe cases
- complications such as: artery wall thinning, blood clots, bleeding, infection
- fatty deposits can accumulate on the stent and block the artery again
- patient may have to change lifestyle
mechanical replacement heart valve
- made of titanium/polymers
- very durable
- blood thinners must be taken to prevent formation of clots
biological replacement heart valve
- from pigs or human donors
- not as durable
- no additional risk of clotting
artificial pacemaker
device planted into the chest attached to the heart that sends out a strong electrical signal to make the heart beat properly
why an artificial heart
- patients who are young and very ill
- as a placement until people can get a real heart
arguments for artificial hearts
- will keep a patient alive
arguments against artificial hearts
- wear out
- patients with them usually need to stay in hospital - machinery
- still at experimental stage
adaptations of exchange surfaces
- large surface are - more diffusion
- thin wall - shorter diffusion distance
- rich blood supply - maintains concentration gradient
change in composition of exhaled and inhaled air
exhaled air has more CO2 than inhaled air - aerobic respiration
gas exchange
exchange of oxygen going into the blood with the CO2 going out of the blood
structures involved in gas exchange
- rings of cartilage - prevent collapse
- trachea
- bronchioles
- ribs
- lungs
- alveolus (alveoli)
- bronchus (bronchi)
how are alveoli adapted for gas exchange
- very thin walls - shortens diffusion distance
- breathing, in and out - maintains a high diffusion gradient
- moist inner lining - allows gases to dissolve before diffusing into blood
- many alveoli - increase surface area for diffusion
- good blood supply - maintains steep diffusion gradient by removing oxygen and supplying large amounts of CO2
breathing in
- ribs move up and out - diaphragm flattens and volume of chest increases
- increased volume means lower pressure
- atmospheric pressure higher than chest - draws air into lungs
breathing out
- ribs fall - diaphragm moves up and volume of chest gets smaller
- decreased volume means increased pressure in the chest
- pressure in chest higher than out - air forced from the lungs
what causes the diaphragm to flatten
ribs moving up contracts the muscles
what causes ribs to move down
intercostal muscles
process of breathing in
- intercostal muscles contract
- ribs move up and out
- diaphragm contracts and flattens
- volume of chest increases
- pressure in chest decreases
- air is drawn into the lungs
process of breathing out
- intercostal muscles relax
- ribs move down and in
- diaphragm relaxes and moves up
- volume of chest decreases
- pressure inside chest increases
- air forced out the lungs
ventilation
process of getting oxygen from the atmosphere
respiration
using oxygen in mitochondria exchange for glucose
phloem cells
cell walls between cells break down to form sieve plates which allows flow of sugar solution
xylem cells
contain spiral rings of lignin to make them stronger
root hair cells
large surface area to increase water uptake
palisade cell
contain many chloroplasts (containing chlorophyll) that trap light needed for photosynthesis
function of mitochondria in root hair cells
releases energy through respiration
functions and adaptations of the xylem
- transports water from the roots
- thick walls stiffened with lignin to withstand high water pressures
- no end walls between cells to allow the continuous flow of water
- water flows in one direction to evapourate from the leaves
functions and adaptations of the phloem
- transports glucose made in photosynthesis in the leaf to other parts of the plant where it is needed
- sugar solution can flow in both directions
- sieve plates (perforated cell walls) allow the flow of sugar solution
- companion cells provide the required energy
functions and adaptations of the epidermis
covers surface of the leaf to provide protection and prevent water loss
transparent to allow light through
functions and adaptation of the palisade mesophyll
- allows for gas exchange
- many chloroplasts mean more chlorophyll
- packed with chloroplasts
functions and adaptations of the spongy mesophyll
- layer of irregularly shaped cells where gas exchange occurs
- many air spaces create large surface area for gas exchange
why do plants need water
- reactant in photosynthesis
- allows plant cells to remain turgid
- transports dissolved minerals around the plant
transpiration
the loss of water through the stomata
transpiration stream
passive movement of water up the xylem and out of the stomata
what happens in the roots
- water moves from the soil to the root hair cells via osmosis
what happens in the stem
- water moves up the xylem in a continuous column due to cohesion
what happens in the leaf
- water exits the xylem via osmosis and enters the leaf cells for photosynthesis
what happens in the stomata
- water diffuses out of the spongy cells into airspaces and then evapourates through transpiration
stomata
- pores found on the undersides of leaves
- site of gas exchange
- open when it is light, close when it is dark
what factors can affect transpiration
- temperature
- humidity
- abundance
- wind intensity
- light intensity
effect of temperature on rate of transpiration
increased temperature, increased transpiration
- concentration gradient will steepen
- increased kinetic energy means water molecules evapourate faster
effect of humidity on transpiration
increased humidity, decreased transpiration
- concentration gradient will steepen the concentration gradient the other way
effect of abundance of stomata on transpiration
increased stomata, increased transpiration
effect of wind intensity on transpiration
increased wind velocity, increased transpiration
- wind blows water away from the stomata as soon as it is released
effect of light intensity on transpiration
increased light intensity, increased transpiration
adaptations of a xerophytic plant
- very waxy cuticle
- sunken stomata
- spines not leaves (lower the surface area)
- silvery hairs
- less stomata
translocation
movement of photosynthetic products in the phloem
what happens in translocation
sugars and amino acids move from where they are made (sources) to where they are needed (sinks)
functions and adaptations of the guard cells
open and close the stomata
- controls size of stomatal opening
how does diabetes cause body cells to lose more water
