exchange and transport Flashcards
how are substances exchanged in single-celled organisms
substances diffuse directly into / out of cell
diffusion is quick due to small distance
why do multi cellular organisms need transport systems
- large distance between cells
- large distance between cells and outside environment
- low surface area to volume ratio
- higher metabolic rate so use oxygen / glucose fast
Describe structure and function of root hair cell
Absorbs water (osmosis) and mineral (nitrate) ions (active transport) Millions of microscopic hairs on a single branch to increase surface area - increase rate of absorption
what are alveolus made from?
single layer of thin flat cells : alveolar epithelium
Describe gas exchange in the alveoli
Oxygen diffuses out of alveolar space into blood
Carbon dioxide diffuses into alveolar space
Describe the blood supply to each alveoli
Each alveoli has its own blood supply due to the surrounding capillary network
Describe blood supply / ventilation of fish gills
- fish gills contain large network of capillaries to keep blood supply high
- well ventilated (fresh water constantly passing)
Both help maintain concentration gradient of oxygen
Describe the where air goes when you breath in (4)
- air enters trachea
- trachea splits into two bronchi
- each bronchus branches off into bronchioles (small tubes)
- bronchioles end in alveoli (gas exchanged)
name the 3 things that work together to move air in/out
- rib cage
- intercostal muscles
- diaphragm
what is a goblet cell ?
cell in the lungs that secretes mucus
why is mucus needed in the lungs ?
traps microorganisms and dust particles in air, preventing them from reaching alveoli
what does cilia do in the lungs?
moves mucus upward towards the throat, where its swallowed - this helps prevent lung infections
what do elastic fibres in the lungs do ?
help with the process of breathing out - elastic fibres stretch when breathing in, then the fibres recoil, pushing air out
what does smooth muscle do in the lungs?
controls diameter of tubes (e.g. trachea) - during exercise they relax, widening the tubes, meaning less resistance to airflow
why are there rings of cartilage in the walls of the trachea and brochi ?
provides support (strong and flexible) so that they don’t collapse when breathe in and pressure drops
describe cartilage in trachea
large C - shaped pieces
describe cartilage in bronchi
smaller pieces
Describe inspiration (6)
- external intercostal and diaphragm contract
- rib cage moves up and out
- diaphragm flattens
- = volume of thorax is increased
5 lung pressure decreases - air flows into lungs
why does inspiration require energy and expiration doesn’t ?
inspiration is an active process, respiration is a passive process
Describe expiration
- external intercostal and diaphragm relax
- rib cage moves down and in
- diaphragm becomes curved
- = volume of thorax decreases
- air pressure increases
- air forced out of lungs
how can expiration be forced ?
internal intercostal muscles contract, pulling rib cage down and in
what is tidal volume ?
vol of air in each breath at rest - usually 0.4dm3
what is vital capacity ?
max vol of air that can breathed in / out
what is breathing rate ?
breaths per (time) - usually bpm
what is oxygen uptake ?
rate at which an organism uses up oxygen
e.g. dm3 / min
what is residual volume ?
vol of air remaining in lungs after exhalation
what is dead space ?
air in bronchioles, bronchi and trachea (no gas exchange)
what is inspiratory reverse volume ?
vol of extra air breathed in over tidal vol
what is expiratory reverse volume ?
vol of extra air exhaled over tidal vol
what is ventilation rate ?
vol of air inhaled in specific time
Describe the counter-current system in fish
- blood flows in gills opposite direction to water, which maintains high conc gradient (Oxygen conc in water higher so it diffuses into blood)
How are fish adapted for ventilation ?
- high surface area on gills
- gill plates have lots of blood capillaries
- thin surface layer of cells
- large conc gradient (counter-current)
What causes the gills to have a large surface area ?
Each gill made from thin branches called gill filaments. Gill filaments covered in tiny structures call gill plates.
What are gills supported by ?
gill arches
how many types of bronchioles are there ?
3 ( larger / smaller / smallest )
which lung parts don’t have smooth muscle ?
smallest bronchiole / alveoli
which lung parts have elastic fibres ?
all of them
which lung parts have goblet cells ?
trachea / bronchi / larger bronchiole
which lung parts don’t have cilia ?
smallest bronchiole / alveoli
what is the purpose of the soda lime in the spirometer
absorbs carbon dioxide
why must fish have special adaptations for getting enough oxygen ?
lower oxygen conc in water than air
outline how water is drawn in of fish mouth
- mouth opens
- lowers floor of buccal cavity
- vol increases, pressure decreases
- water sucked into cavity
outline how water is drawn out of of fish mouth
- mouth closes
- raises floor of buccal cavity
- vol decreases, pressure increases
- operculum forced open
- water leaves out of gills
what is the operculum ?
bony flap covering gills
