Chapter 7 Flashcards
Single called organisms don’t need specialised each Shen because!
- there metabolic demand is not thst high so not as much o2 needed and co2 produced
- they have HIGH SA:V ratios
- diffusion distances are small enough so ti can happen through own membrsnes (DONT need transport)
Which means the rate if diffusion through their membranes is enough to sustain their oife processes
Why do multicellular need then?
Metbsokic demand are much higher, more amount of o2 needed and co2 produced
- they have lower SA:V ratios and their diffusion distances are big, meaning diffusion csnt happen effienclty enough to sustain their huge metbsokic demands and life processes anyways
AS a result need something which specialised for diffusion , snd then a transport system because the distances are too small
4 featured they all have a food special side dexchange SURFSCE
1) HIGH SA : V ratio, this increases rate of diffusion as there is more SURFSCE area aviakbek to diffude into for a given volume , so like alveoli, villi
2) small diffusion distances, this increases rate of diffusion , alveoli 2 cell thick
3) and good concentration gradient
- this can happen in two ways
1) a good blood supply means blood with the product needed to be exchanged is constantly brought to area m snd blood that has just received product is removed and free supply brought, this ensures conc grsdient always high and so rate ifndiffuoj is highest
2. Ventilation, same concept applies, air with o2 always brought snd once diffuses brought away so conc still there’s same for co2
Rick’s law ?
Rate of diffusion is proportional to concentration grsdient x SA / diffusion distance (ignore temp)
Describe the organs and the way air moves into the red blood cells
1) enters through nostril / mouth and goes through nasal cavity
- then down to larynx
- trachea
Bronchi
- bronchioles l
Alveoli
So mani thing is mouth nasal larynx trachea bronchi bricnhioles alveoli
Trachea pipe
Extra structure
In the rib cage there are external intercostal muscles snd internal intercostal muscles that can contract and release to move rib cage snd csuse pressure changes
There is diaphragm, which is n shaped pushing up
Thorax I guess is everything containing air including lungs where bottom is diaphrsgm. Thor’s I. Volume refers to volume in this whole system
There is membrsnes surrounding thr lungs snd fluid inbyeeeen so membrsnes slide essilky over each other as you breate
Inspiration,
Inspiration is the act of breathing in and it requires energy!
- diaphragm contracts , and so it flattens and lowers
- and EXTERNAL INTERCOSTAL MUSCLES CONTRACT, moving the rib cage up and outwards
- this increases thoracic volume , which devreases pressure here
- as there is Greater pressure in atmospher thsn lungs, pressure grsdient, snd sir is drawn in the nostril nasal cavity larynx tracheotomy bronco bronchiole alveoli snd then blood, to EQUALISE THE PRESSURE on the outside
So again
Active pricess
- diaphragm ckntsrdts , snd so flsggens snd lowers
- external intercostal muscles contract, moving rib cage upwards snd outwards
- this increasenthorrifsx volume so pressure decrease
- more pressure a rooster, so sir is drawn in the lungs to equalise the pressure
Expiration
Can Be bith active and passive but mostly passive
- here the diaphragm relaxes so moves upwards sgsin
- and external intercostal muscles releaxtoo, and so rib cage moved inwardsa and down, and this is helped by gravity
- also due to ELASTIC RECOIL, ALVEOLI in lungs also return to normal shape , again reducing volume
- this reduces throwcic volume here, and so oresdure increases in the lungs.
- as there is more pressure in thrlungd thsn the stmospheremoreddurengrwdient, snd sir is expelled back to equkaisethe pressure
However when you want more air to forcefully be pushed out
- diaphragm is contracted harder and faster, causing volume to decrease gene more
- INTERNAL INTERCOSTAL MUSCLES CONTRACT, which pulls down rib cage even more , making volume less and pressure even more
Abdominal muscles contract forcing diaphragm to move up quicker, causing less volume quicker and more pressure, more pressure means more air is pushed out
Nasal cavity
- has a large surface area with good blood supply, and this means the air around enter at same temp to body temperature
- has a hairy lining which secrets mucus to trap duets snd bacteria , protecting lung tiddue from infection
- it has moist surfaces which increase the humidity of incoming air , which is vital
- here the fact that the kingdom are already humid to allow gas to dissolve in and out, if the nasal dairy was simply dry water would leave by osmsis to here. This artificially create humidity by using warm blood snd making it moist so that the concentration gradient is very similar so that no water is lost from thr lungs
Again
# hairy lining secrete mucus trap dirt protect lungs
- good blood supply and SURFSCE area which not only warms incoming air, but as itnid moist, it makes it humid too
Essential because lungs humid already so that oxygen enters dissolving , if nasal cavity wasn’t humid water would kesve
Trachea structure
Wide stube supported by INCOMOLETE CARTILLAGE RINGS
- cartiskle rings give it steufture snd help it withstand fhsnges in oresdure from collapsing
- but they are incomplete so that food can still enter behind them in oesophagus , and also incomplete for that reason due ti air edonsding
2) cilated epithelial tissue
- have goblet cells which produce sticky mucus which traps and bacteria etc. Then cilia rhtmicslly beats do thst this can be oushef to the digestive system or away and protect lungs
3) smooth muscles + elastic fibres
Trachea steufture
- incomplete cartilage rings for suporit. From being collapsed due to pressure
- collated epilthslie tiddue so that mucus can be wafted away from tradheanti digestive and protect lungs
- it also has smooth muscle and elastic fibres
What 4 materials found in the structured and what Süd- firn
Smooth muscle = TRACHEA, BRONCHI , BRONCHIOLES (not alveoli )
- can contract which changes the diameter of the structure, for example during exercise the smooth muscle contracts, which increased diameter and allows airway to flow better moving in and out More easily you
Elastic fibre ( all and especially alveoli) Allow the vessels to expand when under pressure but then due to elastic recoil return back to Orginal shape, this is useful as it helps PUSH AIR OUT
Cartillage = ONLY FOR TRACHEA AND BRONCHI
Rings of cartilage found in the trachea and the bronchi allow for structure to be maintieind underdifferent pressures and stops it from collapsing, these are incomplete
Cillated epithethelial tissue ( everything except alveoli)
This has goblet cells produce mucus capture dirt Cillia waft away and to digestive system to protect lungs
Bronchioles structure
Contains
- smooth muscle
- elastic fibre
- collated epithethilal
Smooth muscle effect here, can control how much air goes in and out based on contracting or relaxing like in exercise
Has some Squamous epithelial tissue which allows gas exchange
Alveoli structure
- has squamous epithelium tissue to allow for gas exchange with blood
- elastic fibres and collagen to allow for elastic recoil this is mostly when elastic recoil haooend, during expiration, allows air to be expelled much more eaill
- no ciliated or smooth muscle
All 4 structured summary
Trachea
- incomplete cartilage rings
- smooth muscle, cillated epitheila , elastic fibres
Bronchi
- left and right bronchi split
- also has csrtiallge rings but smaller
- smooth muscle, cillated and elastic
Bronchioles
- these small don’t have cartilage rings, but some have squamous for gas exchange
- the smooth muscle most prominent here, under excessive can change diameter and control hoe much air goes in
- still has cillated except for small and elastic fibres too
Alveoli
- complete squamous
-elastic fibres with collagen allows for elastic recoil in expiration
- no cilkiate or smooth muscle here
- 4 adaptations d
Adaptations alveoli have
- high SA : V , not just because small but so many alveoli means in total entire surface area higeee
- Small diffusion distance (two cells)
This is one cell thick capillarity and one cell thick alveoli walls so very small - good blood supply and good ventilation
Ensures blood that had been diffused into is constantly removed and blood difufsed out of aswell, so cinc grsdient high
Air diffused out of is removed and new air brought in again increase cinc grsdient so diffusion more effluence
Why is inside of alveoli MOSIT TOO ,And WHAT ABOUT SURFACTSNT
MOIST MEANS OXYGEN CAN DISSOLVE INTO THIS FIRST SND THEN DIFFUSE, OTHERWISE IT CANT GO IN
SUFACTNAT IN SLVEOLI ENDURES IT STAYS INFLATED!
What is entire structure of alveoli now
- alveoli has squamous split helix tissue for gas exchange, elastic fibre and collagen to help in elastic recoil, surfactant to keep inflated snd also moist so thst oxygen can diffuse in
The fact that is mosit means water csn diffuse out, but that’s why nasal cscity hss good supply of blood in surface area , and also mosit, which means it create a humid environment and this keeps cinc grsdient between the lungs and nsssl cscity loe snd so less water is lost
What happens in asthma attack?
Smoking? Smokers cough
Cells lining bro Nicole’s react to something like dust and do inflsmotry reposje, and so release histamines . Histmines cause swelling and inflamed of the bronchioles,
- it also stimulates goblet cells of the cillaofed to release more mucus and also the smooth muscle to construct, this makes the pathway very very narrow, so less wir can go in and out snd it makes it difficult to Brewster
Ina stems attack something like dust stimulates cell lining the bronchioles to release histamines
- histamines cause excess mucus production, smooth muscle to contract and the bronchioles to inflame
This reduced pathway and makes hard to breathe
Smoking makes Cillia stop besting of cillaifed tisdue around trachea bronchi bricnhioles etc , snd this means mucus not pushed down as much forcing edpuksive reflex as a cough, snd this increased chsnce of infection too
Surfactant effect of babies!
We know surfactant prevents alveoli from collapsing. Baby first breath needs insane surfactant so thst the alveoli don’t remain closed once sir is breshted out, or the second breath would be as hard as first , and alveoli is not collapsed
Thing is surfactant inky produced after 30 weeks snd so before this if bsby premature is because lack of sufsctsht , so they need srtifcsl sufsctsnt to make bsby suffices
Donsufsctsnt mskes the alveoli not collapse and prevents is from collapsing snd sticking together when expelling sir (just liquid stops alveoli from sticking basically)
How can volume air be measured now
Peak flow meter, this id the asthma thing blow hard
- spirometer
