Gas exchange/ breathing Flashcards
by which process does gas exchange occur
diffusion
who do single celled organisms respire
through exchange of gases by diffusion through the cell membrane
how to fish respire
gills are gas exchange organs
how to increase effieciency of gas exchange
larger SA- increase rate of transport
Short diffusion distance
how does gash exchange occur in plants
oxygen diffuses down conc. gradient from a high to low conc. (outside to inside leaf)
3 key gases during gas exchange
carbon dioxide
oxygen
water vapour
pathway of CO2 in plants
atomosphere
air spaces around spongy mesophyll
leaf mesophyll cells
cholroplast
adaptation of whole leaf for gas exchange
thin (short diffusion)
flat (large SA:V)
many stomata (maintain gradient)
air spaces
what is a stomata
spaces found between 2 guard cells on the lower epidermis of the leaf
what are guard cells responsible for
opening and closing stomatal pore which controls gas exchange and water loss
when do stomata open
when water moved into cells causing them to become turgid
how do guard cells being turgid allow gas exchange
allows gases to diffuse in and out through stomatal pore
rate of photsynthesis and respiration during the day
plants do oth but rate of photosynthesis is higher.
- net diffusion of co2 into the plant and net diffusion of oxygen out of plant
rate of photsynthesis and respiration during the night
plants only respire
- there is net movement of oxygen into plant and net diffusion of CO2 out of plant
rate of photsynthesis and respiration at low light intensities
equal so there is no net movement of oxygen or carbon dioxide in either direction
what is the gas exchange surface in humans
lungs
adaptations of lungs
large SA:V
Thin walls
good ventillation
good blood supply
ribs
bone structure that protects internal organs such as lungs
intercoastal muscle
muscles between ribs which control their movement causing inhalation and exhalatoin
diaphragm
sheet of connective tissue and muscle at bottom of thorax
- helps change the vol. of thorax to allow inhalation and exhalation
trachea
windpipe that connects the mouth and nose to lungs
larynx
aka voicebox
air passes across here to make sound
bronchi
large tubes branching off the trachea with one bronchus for each lungs
bronchioles
bronchi split to form smaller tubes called bronchioles in lungs connected to alveoli
alveoli
tiny air sacs where gas exchange takes place
pleural cavity
fluid-filled space between the pleural membranes wihch reduces friction and allows the lungs to move freely
what are the passages down to lungs lined with
ciliated epithelial cells
what are cilia cells
tiny hairs on end of them that beat and push mucus up the passages towards the nose and throat
goblet cells
mucus made by special mucus producing cells
what does mucus do
traps particles, pathogens and prevents them from getting into the lungs
external intercoastal muscles
pull the rib cage up
internal intercoastal muscles
pull the ribcage down
diaphragm
thing sheet of muscle that separates the chest cavity from the abdomen
during inhalation
- diaphragm contracts and flattens
- external intercoastal muscles contra
- pulls ribs up and out
- this increases vol of the chest cavity
- leads to decrease in air pressure inside lungs
- air drawn in
during exhalation
- The diaphragm relaxes it moves upwards back into its domed shape
The external set of intercostal muscles relax so the ribs drop down and in
This decreases the volume of the chest cavity (thorax)
Leading to an increase in air pressure inside the lungs relative to outside the body
Air is forced out
adaptations of alveoli for gas exchange
- theyre thin
- single layer cells
- large SA:V
- Ventiliation
- good blood supply
- layer of moisture
what does smoking cause
chronic obstructive lung disease
coronary heart disease
lung cancer
tar
carcinogen that causes cancer
nicotine
addictive substance which narrows blood vessels
carbon monoxide
reduces oxygen carrying capacity of blood
nicotine bad side effects
increases heart rate
leads to heart attack
how does tar cause chronic bronchitis
stimulates goblet cells and mucus glands to enlarge producing mucus.
It destroys cilia and mucus build up blocking smallest bronchioles
Emphysema
- caused by frequent infection
- phagocytes break down elastic fibres in alveoli causing them to be less elastic
- reduces SA
