EXCHANGE AND TRANSPORT (3.1.1) Flashcards
- describe the exchange system of single-celled organisms
- explain why this is the case
- substances can quickly diffuse directly into or out of the membrane
- due to high SA:VOL ratio
- short travel distance
- describe the exchange system of multi-cellular organisms
- explain why this is the case
- exchange surfaces are required, substances cannot diffuse through membrane, due to
- low SA:VOL ratio
- large distance to travel
- higher metabolic rate
- state 3 features that improve efficiency of exchange surfaces
- explain why they are beneficial
- Large surface area - increases the amount that can be absorbed/excreted
- Thin - decreases the distance that substances need to travel
- Good blood supply - good ventilation means a concentration gradient is maintained
State the the purpose of goblet cells regarding gas exchange
- trachea - bronchi - large bronchiole
- secrete mucus, trapping microorganisms and dust particles (in inhaled air)
- stops them from reaching the alveoli
State the purpose of ciliated epithelial cells regarding gas exchange
- hairlike structures on surface of epithelial cells lining airways
- beat mucus and microorganisms trapped within it up away from the alveoli
- prevents lung infections
State the purpose of elastic fibres regarding gas exchange
- found in walls of trachea, bronchi, bronchioles and alveoli
- stretch as lungs expand during inhalation, the recoil to push air out of lungs during exhalation
State the purpose of smooth muscles regarding gas exchange
- found in walls of trachea, bronchi and large/medium bronchioles
- controls their diameter and how easily airflow can move in or out of lungs
Which parts of the gas exchange system contain cartilage
- trachea ( large c shaped pieces)
- bronchi ( small pieces )
Which parts of the gas exchange system contain smooth muscle
- trachea
- bronchi
-large bronchiole - medium bronchiole
Which parts of the gas exchange system contain elastic fibres
- trachea
- bronchi
- large bronchiole
- medium bronchiole
- smallest bronchiole
- alveoli
What parts of the gas exchange system contain goblet cells
- trachea
- bronchi
- large bronchiole
Which parts of the gas exchange system contain ciliated epithelium cells
- trachea
- bronchi
- large bronchiole
- medium bronchiole
Describe the structure of the overall gaseous exchange system
- during inhalation, air enters the trachea which splits into 2 bronchi
- each bronchus leads into each lung and branches off into bronchioles
- bronchioles end in many alveoli
- rib cage, intercostal muscles and diaphragm work together for inhalation and exhalation
- describe what happens to the gaseous exchange system during inhalation
- is this an active or passive process
- External intercostal muscles and diaphragm contract - ribcage moved up and outwards and diaphragm flattens
- The volume of the thorax increases and lung pressure decreases - causing air to flow into lungs
- active process, requiring energy
- describe what happens to the gaseous exchange system during exhalation
- is this an active or passive process
- External intercostal muscles and diaphragm relax - ribcage moves down and in , diaphragm reverts to curved
- Volume of thorax decreases, lung pressure increases - air flows out of lungs
- normal inhalation is passive, but can be forced
Define tidal volume
- volume of air in each breath
- normally 0.4 dm^3
Define vital capacity
Maximum volume of air that can be breathed in or out
Define breathing rate
- number of breaths taken per unit of time
- (e.g. breaths per minute)
Define oxygen uptake
- rate at which a person uses O2
- e.g. no. Of dm^3 per minute
Describe the structure of a gill
- supported by Gill Arch
- many thin plates, Gill Filaments
- (primary lamellae) covered in tiny structures, Gill Plates (secondary lamellae)
- describe the counter-current system present in fish
- how does this increase efficiency of diffusion of Oxygen
- blood flows over gill plates, whilst water flows over in the opposite direction
- water with a high O2 concentration will always flow next to blood with low O2 concentration
- maintains a steep concentration gradient between water and blood, allowing O2 to diffuse into the blood for respiration
What is the operculum
Bony flap which covers and protects the gill
Describe the ventilation process in fish
- Opens mouth, volume of buccal cavity increases, pressure decreases
- Water sucked into the cavity
- Closes mouth, volume of buccal cavity decreases, pressure increases
- Water forced outside of the cavity, across the gill filaments (primary)
- Increased pressure forces each operculum to open
- Water leaves through the gills
Describe the ventilation process within insects
- Air moves into the tracheae through spiracles
- O2 travels down conc gradient towards cells
- CO2 travels down conc gradient from cells towards spiracles to be released
- Trachea branch into tracheoles, containing liquid which O2 dissolves in
- O2 diffuses from liquid to body cells
Describe how insects ventilation system is specialised for efficient gas exchange
- abdominal movements used to move air in and out of spiracles
- tracheoles have thin, permeable walls to decrease diffusion distance
- tracheoles have fluid which O2 dissolves in
Explain how fish have adapted to live with little O2 in water
- many thin gill filaments: provide large surface area for gas exchange
- many thin gill plates: increase surface area, decreased distance for diffusion
- gill plates have manny blood capillaries: speed up diffusion between water and blood
What is a spirometer
Machine used to investigate breathing
Define tidal volume
- volume of air in each breath
- usually 0.4dm^3
Define vital capacity
Maximum volume of air that can be breathed in or out
Define breathing rate
Number of breaths taken per unit (e.g. breaths/min)
Define oxygen uptake
Rate at which a person used oxygen (e.g. number of dm^3/minute)
Define inspirational reserve volume
Max volume that can be inhaled after a normal breath
Define expiratory reserve volume
Max volume off air that can be exhaled after a normal breath
Why does overall volume in a spirometer decrease
- air breathed out by the person is a mixture of O2 and CO2
- CO2 absorbed by soda lime in the machine
- only O2 inhaled by the person
- O2 used up by respiration
- volume gradually decreases
How is breathing rate for first minute determined from a spirometer trace
Count number of peaks in the first minute
Describe how tidal volume is determined from a spirometer trace
Count the volume of gas in the spirometer in an average breath
How is vital capacity determined from a spirometer trace
Count the volume of gas in the spirometer between the max exhale and max inhale
How is oxygen uptake determined from a spirometer trace
- count the decrease in vol of air in the spirometer from the average slope on the trace
- ex. For the first minute
Describe the processes that occur during inspiration
- External intercostal muscles and diaphragm contract
- Ribcage moves up and outwards, diaphragm flattens
- Thorax volume increases, lung pressure decreases
- Air flow rushes into lungs
Describe the processes that occur during expiration
- External intercostal muscles and diaphragm relaxes
- Ribcage moves down and in, diaphragm returns curved
- Thorax volume decreases, lung pressure increases
- Air flows out of the lungs
Is inspiration or expiration an active process
Inspiration, forced expiration is active
Normal expiration is passive
Describe how to use a spirometer
- Person breathes through tube connected to O2 filled chamber
- Chamber moves up and down, recorded, produces a spirometer trace
- Soda lime in tube absorbs CO2 from persons exhale
Describe how to use a spirometer
- Person breathes through tube connected to O2 filled chamber
- Chamber moves up and down, recorded, produces a spirometer trace
- Soda lime in tube absorbs CO2 from persons exhale
