module 3.1 Flashcards
whats the alveoli
tiny folds in the lung epithelium to increase sa
whats the bronchi and bronchioles
smaller airways leading into the lungs
whast the diaphragm
a layer of muscle beneath the lungs
what are the intercostal muscles
muscles between the ribs. contraction of the external intercostal muscles raise the ribcage
whats the trachea
the main airway leading to the back of the mouth to the lungs
ventilation
the refreshing of air in the lungs, so that there is a higher oxygen conc. in the blood, and a lower co2 conc.
where does the exchange of gasses take place?
the alveoli
what must the lungs maintain to ensure gas diffusion can continue
a steep gradient
adaptations of the alveoli (general)
- large sa
- thin layer of moisture
- thin barrier for molecules to diffuse across (animal cells don’t have cell walls)
where does oxygen diffuse from
from the alveoli to the blood in the capillaries
what are the 5 adaptations that reduce the distance gasses have to diffuse- gas exchange
- the alveolus is one cell thick
- the capillary wall is one cell thick
- both walls consist of squamous cells ( flattened or very thin)
- the capillaries are in close contact with the alveolus wall
- the capillaries are so narrow that the red blood cells are squeezed against the capillary wall making them closer to the air in the alveoli and reducing the rate of flow.
what helps maintain a steep concentration gradient in the lungs
a good blood supply:
- the blood system transports co2 from the tissues to the lungs, this ensures the conc of the co2 in the blood is higher than that in the air of the alveoli thus co2 diffuses into alveoli
- blood also transports oxygen away from the lungs, this ensures the conc of o2 in the blood is kept lower than that of the alveoli so that o2 diffuses into the blood
what does ventilation ensure?
- the conc of o2 in the air of the alveolus remains higher than that in the blood
- the conc of co2 in the alveoli remains lower than that in the blood
whats inspiration
inhaling
whats expiration
exhaling
what occurs during inspiration
- the diaphragm contracts to move down and become flatter- this displaces the digestive organs downwards
- the external intercostal muscles contract to raise the ribs
- the volume of the chest cavity increases
- the pressure in the chest cavity is increased
- air is moved into the lungs
what occurs during expiration
- the diaphragm relaxes and is pushed up by the displaced organs underneath
- the external intercostal muscles relax and the ribs fall; the internal intercostal muscles can contract to help push air out more forcefully- this usually only happens during exercise or coughing and sneezing
- the volume of the chest cavity decreases
- the pressure in the lungs increases and rises above the pressure in the surrounding atmosphere
- air is moved out the lungs
what happens to the elastic fibres in the alveoli during inspiration and expiration
during inspiration the walls stretch and then recoil to help push out air during expiration
what are the airways (trachea, bronchi and bronchiole’s) lined with
lined by ciliated epithelium which contributes to keeping the lungs healthy- goblet cells in the epithelium release mucus which traps pathogens, the cilia then moves the mucus up to the top of the airway.
what do the trachea and bronchi have/ are supported by- what does this allow for
- supported by rings of cartilage which prevent collapsing during inspiration- they are C-shaped which allow for flexibility and space for food to pass down the oesophagus
state things about bronchioles
- narrower than bronchi
- larger ones may have cartilage but smaller ones wont
- wall is comprised mostly of smooth muscle and elastic fibres
how can smooth muscle constrict the airway
by contracting
why is controlling the flow of air important via smooth muscle
- if there are harmful substances in the air
how does smooth muscle no longer contract/ become elongated
by elastic fibres- they recoil to their original size and open the airway
whats breathing rate
the number of breaths per minute
whats oxygen uptake
the vol of oxygen absorbed by the lungs in one minute
whats tidal volume
the vol of air inhaled or exhaled in one breath, usually measured at rest
whats vital capacity
the greatest vol of air that can be expelled from the lungs after taking the deepest possible breath
whats a spirometer
a device that can measure the movement of air in and out of the lungs
how is a spirometer used and what does it measure, what does it consist of
- the device measures the movement of air in and out of the lungs as a person breathes.
it consists of: a chamber of medical grade oxygen or air floating on a tank of water, during inspiration, air is drawn from the chamber so that the lid moves down. During expiration, the air returns to the chamber raising the lid. these movements may be recorded on a data logger, this produces a trace. - the co2 rich air exhaled is passed through the chamber of soda lime, which absorbs the co2. this allows the measurement of o2 consumption
what are the 5 precautions that must be taken when using a spirometer
- subject should be healthy and free from asthma
- the soda lime should be fresh and functioning
- there should be no air leaks or this would give inaccurate results
- mouthpiece should be sterilized
- water camber should not be overfilled
what does total lung volume consist of
the vital capacity (can be measured)
the residual volume (cannot be measured using spirometer)
what three factors dos vital capacity depend on
- the size of person
- their age and gender
- their level of regular exercise
what is residual volume
-the vol of air that remains in the lungs even after forced expiration. this air remains in the airway and alveoli
how do u calculate oxygen uptake from a spirometer
on trace draw a lie form point A down to the horizontal axis, and another line form point B to the horizontal axis.
measure the length of time between these points
-measure the difference in volume between points A and B
-divide the time taken for this decrease
unit=dm3s-1
increased oxygen uptake will result from…(2)
- increased breathing rate
- deeper breaths
what’s the buccal cavity
the mouth
what’s the countercurrent flow
where two fluids meet in opposite directions
what’s the filaments
slender branches of tissue that make up the gill. they are often called primary lamellae.
what’s the lamellae
sometimes called secondary lamellae.
-folds of the filament to increase sa. They arte also called gill plates
what’s the operculum
-a bony flap that covers and protects the gills
what’s the spiracle
an external opening or pore that allows air in and out of the trachea
what’s the tracheal fluid
the fluid found at the end of tracheoles in the tracheal system.
what’s the tracheal system
a system of air-filed tubes in insects
state things abt bony fish- why do bony fish have gills
must exchange gasses with the water in which they live. They use gills to absorb oxygen dissolved in the water and release carbon dioxide
how many pairs of gills will bony fish ahve and what are they covered by
- five pairs of gills
- covered by a bony plate called the operculum
what does each gill consist of- what are they like and what does it provide
two rows of gill filaments (primary lamellae) attached to a bony arch. The filaments are very thin, and their surface is folded into many secondary lamellae (or gill plates)- this provides a large sa
where is deoxygenated blood carried close to in fish
secondary lamellae where exchange takes place
describe counter current flow in fish
blood flows along the gill arch and out along the filaments to the secondary lamellae. the blood then flows through the capillaries in the opposite direction to the flow of water over the lamellae. this arrangement of counter current flow absorbs the max amount of water
how does ventilation occur in bony fish
- bony fish can keep water flowing by using a buccal-opercular pump. the buccal cavity (mouth) can change volume. the floor of the mouth moves downwards , drawing water into the buccal cavity. the mouth closes and the floor is raised again pushing water through the gills. movements of the operculum are coordinated with the movements of the buccal cavity. as water is pushed from the buccal cavity, the operculum moves outwards. this movement reduces the pressure in the opercular cavity (the space under the operculum), helping water to flow through the gills.
describe insects circulatory system
- insects have an open circulatory system in which body fluid acts as both blood and tissue fluid. Insects do not transport oxygen in blood. circulation is slow and can be affected by body movements.
insects have an air- filled tracheal system which supplies air directly to all respiring tissues, describe the process of gas exchange
air enters the system via a spore in each segment called a spiracle. the air is transported into the body through a series of tubes called tracheae. these divide into smaller and smaller tubes called tracheoles. the ends of the tracheoles are open and filled with a fluid called tracheal fluid. GAS exchange occurs between the air in the tracheole and the tracheal fluid. some exchange can also occur across the thin walls of the tracheoles.
many insects are active and need a good supply of oxygen so what happens when tissues are active
the tracheal fluid can be withdrawn into the body fluid to increase sa of the tracheole wall exposed to air this means more oxygen ca be absorbed when the insect is active
what are the three ways in which larger insects can ventilate by movements of the body
- sections of the tracheal system are expanded and have flexible walls, these act as air sacs which can be squeezed by the action of the flight muscles. repetitive expansion and contraction of these sacs ventilate the tracheal system.
- movement of the wings alter the vol of thorax. as thorax vol decreases, air in tracheal system is put under pressure and pushed out of tracheal system. when thorax increase in vol, the pressure inside drops and air is pushed into the tracheal system from outside
- some insects such as locusts can alter the vol of their abdomen by specialised breathing movements. These are coordinated with opening and closing valves in the spiracle. As the abdomen expands, spiracles at the front end of the body open and air enters the tracheal system. as the abdomen reduces in vol, the spiracles at the rear end of the body open and air can leave the tracheal system
