biology module 1 exchange Flashcards
What substances do living cells need to keep them alive and why?
Oxygen for aerobic respiration Glucose for energy Proteins for growth and repair Fats for membranes and energy Water Minerals to maintain water potential and help aspects of metabolism
What substances need to be removed and why?
Co2 from animals and micro organisms and plant cells that are actively doing photosynthesis
Oxygen (plants, protoctists)
Urea and ammonia and other wastes which contain excess nitrogen
Explain why large, active organisms need special surfaces for exchange
- small surface area to volume ratio
- cant supply cells with gases and nutrients quick enough to keep them alive
- greater diffusion distance
Describe and explain features that make an exchange surface sufficient
- large surface area: more space for molecules to pass through often by folding walls and membranes
- thin barrier: shorter diffusion distance
- fresh supply of molecule on one side: concentration +
- removal of required molecule: concentration low
Describe inhalation
- diaphragm contracts to be flatter
- intercostal muscles contract to raise ribs
- volume of chest increase
- pressure In chest drop
- air in lungs
Describe exhalation
- diaphragm relaxes
- intercostal muscles relax lower ribs
- volume decreased
- pressure increases above atmospheric pressure
- air out
The role of the cartilage?
- structure
- prevents collapse when air pressure inside is low due to inhalation
- not closed so flexible and oesophagus to expand when eating
The role of smooth muscle?
- contract to constrict the airway which makes the lumen narrower
- most obvious in bronchioles
- controls flow of Air to alveoli if harmful substances present
What is one of the causes of asthma ?
Smooth muscle contracts and airways constrict because of involuntary reaction to allergic reaction
Role of elastic fibres?
When smooth muscle contracts it deforms elastic fibres in loose tissue
- elastic fibres recoil into normal shape
- helps to widen the airway
Role of goblet cells and glandular tissue?
Secrete mucus
Trap tiny particles from the air which may include pollen or harmful bacteria
Reduces risk of infection
Role of ciliated epithelium?
Cilia move in pattern to waft mucus up the airway
Once there it is swallowed
Acidity in stomach kills any bacteria
Tidal volume?
Volume of air moved in and out of lungs with each breath when at rest
Approx 0.5dm3
Vital capacity?
Maximum volume of air that can be moved in and out of the lungs in one breath
Approximately 5dm3
Residual volume?
Volume of air that remains in the lungs after maximum exhalation
Approx 1.5dm3
Dead space?
Air in bronchioles, bronchi and trachea
No gas exchange takes place between this air and the blood
Inspiratory reserve volume?
Amount of air that can be taken in above the normal tidal volume when you take in a big breath
Exploratory reserve volume?
How much more site can be breathed out over and above normal tidal volume breathed in
How does a spirometer work?
- chamber filled with oxygen that floats on a tank of water
- breathing in takes oxygen from chamber so it sinks down
- exhaling puts air in chamber so it floats up
- data logger records data and person can do different breathing to record different things
Name two specialised exchange surfaces one in Animals one in plants and say which substances are transported in or out of that cell
Root hair cells: water and minerals absorbed
Small intestine: nutrients absorbed
Hyphae of fungi: nutrients absorbed
Liver:blood sugar levels adjusted
Describe the journey of air from the outside of our bodies to our lung alveoli
- through the nose
- down trachea
- bronchi and bronchioles
- reaches alveoli where gas exchange takes place
What is the role of surfactant in the alveoli of the lungs
Reduce cohesive forces between water molecules
Alveoli would collapse due to these cohesive forces between water molecules lining the air sac
How Is surfactant produced
Passes through cell membrane of the cytoplasm of the alveolus cells
Explain the action of the transport system maintains a diffusion gradient in the lungs
- blood brings co2 from tissues to lungs
- ensure concentration of co2 in the blood is higher than the air in alveoli
- blood carries oxygen away from lungs
- ensures concentration of blood kept lower than the air of the alveoli
How does ventilation of the lungs maintain diffusion gradient
- brings fresh oxygen in the lungs
- concentration of O2 in the air of the alveolus remains higher than in blood
- removes co2 from alveoli
- ensures co2 in blood kept higher than alveoli
Where are the goblet cells found q
Under the epithelium
Name the three main factors that affect the need for a transport system
Size
Surface area to volume ratio
Level do activity
How does size affect the need for a transport system
If an animal has several layers of cells the nutrients or oxygen needed would be taken up the outer cells
Would not reach the cells deeper within the body
How does surface are to volume ratio affect the need for a transport system?
Small a animals have a large surface area to volume ratio whereas a bigger animal with multiple structures and tissues have a relatively small surface area to volume ratio
-surface area is not large enough for the animal to supply all the oxygen and nutrients needed by internal cells
How does level of activity affect the need for a transport system?
Very active animals need a good supply of nutrients and oxygen to supply energy for movement
Animals such as mammals that keep the,selves warm need even more energy
Features of an effective transport system?
Fluid or medium to flow nutrients and oxygen around body (blood)
Pump to get pressure to push fluid around body (heart)
Exchange surfaces that enable O2 and nutrients to enter and leave blood when needed
Efficient transport system?
Tubes or vessels to carry blood around
Two circuits one to pick up oxygen and one to remove it
What is pulmonary circulation
Blood flowing from the heart to the lungs to collect 02
What is systematic circulation?
Blood flowing from heart to the body to deliver oxygen and nutrients to the tissues
What is the cardiac cycle?
Sequence of events involved in one heartbeat
What is diastole?
When both the atria and ventricles are relaxing
Internal volume increases and blood flows into heart
Blood flows into atria then through atria ventricular valves to ventricles
What is atrial systole?
Atria contract to push blood into ventricles
This stretches the walls of the ventricles and they are full of blood
Contraction of the atria is ATRIAL SYSTOLE.
What is ventricular systole and explain it
Ventricles contract
Raises pressure in ventricles very quickly
Contraction starts at apex of heart so pushes blood in arteries
Semin lunar valves open and blood is pushed out of heart
What causes the atrioventricular valves to open?
When the ventricle walls relax and recoil and the pressure drops to below that in the atria
What causes the av valves to close
When the ventricles contract the pressure in them rises and blood starts to move upwards when the pressure is higher than that in the atria. This fills the valve pockets and keeps them closed which prevents blood back flow