Download Vertebrate Respiration Functions Gas Exchange we animals require

Vertebrate Respiration
Functions
Gas Exchange we animals require oxygen and get rid of Carbon dioxide when
too much of it makes the blood acidic, when lowering the pH of the
blood it will interfere with a lot of the processes/systems in the body
Body needs oxygen – for metabolism, Final electron acceptor in the Electron
Transport Chain
Shifting of electrons allows for release of ATP
Aerobic cellular respiration, anaerobic if you don’t have oxygen
terminates glycolysis end product is lactatic acid
Carbon Monoxide – preferred by hemoglobin will choose this over oxygen,
common form of suicide via burning coal or car fumes
What role does pyruvate play in anaerobic metabolism?
Passive diffusion: simplest form
May be due to diff. in pressure
Gas goes to an area where there is less pressure (negative pressure) vaccum
has to be filled up, principle by which we breathe in air, has to be a
creation of negative pressure
Dependent on surface area and difference in partial pressure
Lower pressure creates a vacum which has to be filled up
When organism gets too large cannot get completely dependent on diffusion
Passive diffusion in the alveoli
But we don’t breathe in the skin
If large organism means the volume is also very large, larger than surface
area
For every linear increase in dimension V=^3
Rely on diff. respiratory surfaces gills alveoli or lungs – essentially filled with
alveoli
Ventilation – flow of respiratory medium over respiratory surface
Medium the one that carries the gas, respiratory surface – one that
gets the gas
Medium water, respiratory surface gills
When ventilating something – running air over it
When fishes ventilate their eggs they flap their fins over their eggs so that
egss will not be coated with fungi
Perfusion - Flow of blood through respiratory surface, driving of blood through
capillaries, (aquatic: capillaries of gills, terrestrial: capillaries of lungs)
Both are involved in unloading and loading gases
There is gas exchange bet. the air and blood, and water and blood,
Intimately connected with each other
it depends on the habitat, ventilation and perfusion rates differ. how quickly
the blood flows. how quickly the water flows
Water is a diff. habitat from air, in terms of oxygen, more oxygen in air, easier
to extract oxygen in air
Given that there is not much oxygen in water and diff. to extract oxygen from
water, Ventilation supplies oxygen, small amount of water small
amount of oxygen, slow flow of water but big flow of flood – blood
wasted cause it can’t get oxygen
Unidirectional vs bidirectional
Bidirectional bec. it goes back humans (it goes back)
Alveoli “any of the many tiny air sacs in the lungs where the exchange of
oxygen and carbon dioxide takes place” are blind and dead closed on
one end
Air will come in through nares nostrils, have to go back air
When new air comes in old air comes out theres mixing
Basic Origins of the Organs
Gills: from pharyngeal slits
Lungs: endodermal outpocketings from the gut
not homologous structures, endodermal
Gas bladders: may be homologous to lungs
Lungless animals that is homologous –swim bladder maybe
homologous to lungs, also come from the gut and serve the same
function
Ventilatory Mechanisms
Ciliatory Mechanism
same as passive type of diffusion, cilia drive water or
air through epithelial lining so that gas will diffuse, we cannot
completely rely due to surface area volume relationship, organisms
get too large surface area not large enough
Muscular mechanisms
Dual pump (water ventilation) – in most fishes, two phases involved,
suction and force phase, depends on two pumps, two cavities,
operculum – bony covering of gills, continuous no gaps bet.
stages
Stage 1 both cavities buccal and opercular cavity expand, when they
expand, water will spontaneously come in, increase in volume
is accompanied by decrease in pressure, water will
spontaneously come in, how they eat, mouths are closed and
when see prey they open their mouth then vacuum is created,
operculum not open
If both mouth or operculum is open at point where two cavities
expand, no negative pressure
Fish needs quick flow of water so that pressure coming from
the water as driving through the gills will pump out
oxygen – bec. of the high speed and pressure of water
Water enter buccal cavity – pass through the gills, gills pick up
oxygen with water and load carbon dioxide with
water
Stage 2 buccal cavity compressing, mouth is closed, if open during
this then water will just go back out through mouth, water is
pumped through gill curtain
Stage 3 pressure is already positive, opercular valve already opens,
pumping or compressing of opercular cavity pumps out, when
negative water goes in, positive water will go out
Stage 4 is beginning of stage 1
Point of water entry is suction
Pump out is force phase
When both cavities expand that’s suction phase, when both
cavities compress water is pumped out force phase
Buccal pump (air ventilation)
When frogs dive in water – amphibians can stay underwater
for quite sometime, do not have gills do not have operculum,
simply breathes through skin when under water relies on
cutaneous respiration
Buccal pump respiration in frogs
Frogs dependent on throat or mouth area
Two types
Two stroke
air breathing fishes and most amphibians
diff. in no. of strokes
Four stroke
When buccal cavity expands, air comes in nostrils are open
there’s something open, opening to windpipe trachea, to
throat, both nostrils and external nares and glottis are open
when mouth expands air enters from the outside through the
nares into the mouth, old air from the lungs comes into the
mouth via the glottis, expiration buccal cavity compresses
Compression – air goes out two ways
Implies that there is mixing of new and old air
Twice as fast but mixing
Four stroke (in some salamaders)each compression phase is split
into two, first stage of inspiration buccal cavity expands, only
one arrow
stage 1 only nares is open glottis is closed, during expansion,
air enters through nares
Stage 2 is compression buccal cavity compresses, glottis is
open, nares closed, through the open glottis, even though
compression still part of inspiration
Expiration starts, air goes into the mouth from the lungs,
buccal cavity compresses, nostrils open, glottis closed,
minimal mixing, a bit of mixing, surface of trachea
Mixing is bad because you’re breathing air that’s not pure –
may be carbon dioxide
Aspiration pump
amniotes, medicine dropper
aspirator valve, very dependent on particular muscles and
creation of negative pressure
Chest cavity – Pl – pleural cavity surrounding the lungs
P pressure
major blood vessel
Superior Vena Cava – drain upper parts of the body, large vein
carrying deoxygenated blood into heart, carrying blood
from the head, arms and upper body
Jugular vein, brachial veins of arm
Inferior Vena Cava– drain lower parts of the body, carrying blood
from lower body
Femoral vein - bring blood back to the heart
Right atrium – where blood enters
blood always receives blood via the atrium not
ventricle, atrium receives blood form the outside
Right deoxygenated blood, left always receives oxygenation
Inspiration Inhalation
Expiration exhalation
Right Atrium
During inspiration lungs expand, diaphragm contracts goes
down, rib cage expands, increase volume of chest cavity, rib
goes forward, increasing volume of pleural cavity, decreasing
the pressure and also in the right atrium (expands) because it
expands bec. of the negative pressure, vein will pump blood
into the right atrium
When chest cavity compresses, pressure is already postive,
Right atrium compresses also, blood flows out of RA into RV
Creation of negative pressure by increasing volume
Compression of parts causes air to go back out bec. of positive
pressure
Phylogeny
Sharks most primitive gnathostomes
Elasmobranchii
Countercurrent flow across the gills, flow of blood and water are in opposite
directions, when in same direction (concurrent flow) why important
in fishe water flows the opposite way, more efficient exchange of
gases, concurrent flow same direction gas exchange will happen only
in point of contact, flowing in the same direction, countercurrent flow
blood is flowing gas exchange happens in all point contact
Fishes face the problem of not having enough oxygen
One modification to allow them to extract oxygen more efficiently: high rate
of water high pressure water coming in, higher ratio of ventilation to
perfusion ratio
Rate of ventilation is higher than perfusion
Some sharks undergo Ram ventilation – forward thrusting motion (obligate
in some)have to moving fast very quickly so that water is forced into
mouth then gills
Required that they have to be swimming like that all the time if they stop
they don’t get oxygen
Eyes do not close but they sleep
Fish keeps moving while asleep, only half of the brain is asleep, moving
forward but still sleeping
First 2 mandibular arch and hyoid arch
In sharks first gill slit reduced as a spiracle – reduced gill slit, slightly for
Chemoreception detecting chemicals in the water
Shark pic
Flow of water through the mouth of shark, unidirectional flow, animals do
not have operculum, same principle as dual pump no opercular flap
covering the gills, what happens is flow of blood, they share similar
functions and structures, in heart (typical fish) pump blood in an
aorta - major artery – bring blood away from the heart artery away
veins back,ventral aorta and dorsal aorta, heart pumps deoxygenated
blood through the ventral aorta
Heart of fish is very basic two main chambers main vein and atrium ventricle
connected to ventricle is Major artery aorta
Ventral aorta carries deoxygenated blood, major diff. bet heart of fishes and
tetrapods, no point the heart will contain oxygenated blood. heart is
supplied with own supply, always deoxygenated, when it came back
from general circulation it was depriveed from oxygen, flows out
through ventral aorta
Branching off from ventral aorta, going toward the gills for oxygenation to
get oxygen from gills, oxygenated blood will be leaving gills, goes into
another set of arteries and into dorsal aorta –carries oxygenated
blood from gills to body, when it already supplied oxygenated blood
to tissues individual veins will come back to heart to carry
One is carrying oxygenated
One is carrying deoxygenated blood
One artery is blue the other one is red
When blood vessel is red it is oxygenated, blue is deoxygenated
Blue which is deoxygenated afferent
Red are efferent
Flow of blood through shark
Counter-current flow happens only in Ventral Aorta, functions only in oxygen
extraction
Osteichthyes bony fishes
Operculum covers the gills
Efferent artery oxygen from gills to dorsal aorta
Some use gas bladders (sometimes connected to the buccal cavity via the
pneumatic duct)
Gas bladder connected via pneumatic duct
Most fishes borrow oxygen from muscles
Gas bladder (swim bladder) are homologous to lungs, internal gas-filled
organ that contributes to the ability of a fish to control its buoyancy
Lung fish doesn’t have swim bladder anymore
Amphibians
Gill ventilation as juveniles
Cutaneous respiration and lung ventilation as adults
When under the water cutaneous respiration bec. lungs collapse
too much pressure
Reptiles
Scales provide barrier in gas exchange, rely on aspiration mechanisms
Single central air chamber with faveoli
(compartments increase surface area and are sites of gas exchange)
Repeated folds of the lungs, to increase surface area but not volume
Sites of gas exchange also serve function of alveoli
Aspiration (exhalation sometimes passive)
In humans it is ussually passive
Inhalation – active bec. internal intercostals pull the ribs
Muscles simply relax not active process
Snake lungs are singular and divided into respiratory and saccular portions
Modification for wider cavity allows them to eat larger
Respiratory portion is the only one that is vascular – supplied with
blood vessels only part of the single large responsible for gas
exchange acts as the diaphragm – important in causing the
creation of negative pressure, spreads out the respiratory
portion of singular lung thus increasing its volume
Saccular – non-vascular no gas exchange simply for compression and
increasing the volume of the lung
Crocodiles – liver moves toward the tail increases the chest cavity, when liver
goes back forward, livers of crocodile are moving
Limb movements, when withdraw limbs into shells, compress chest cavity,
spread legs-expand chest cavity
Turtles limited amount of cutaneous respiration in some parts o their
body particularly around their anal region in some turtles and lizards
Unidirectinal airflow
Non fishes its bidirectional but in alligators its unidirectional flow
Birds
Address diff. problems because they fly
Passageways branch off into parabronchi (unidirectional)
Flow of air will be unidirectional, their air sacs are not blind and dead
and they’re in series, parabronchi will be respiratory surfaces
for gas exchange, each of this will get oxygen, has to be
efficient, fly up where atmosphere is much thinner
With 6-12 (usually nine) avascular (no blood vessels no gas exchange) air
sacs, which extend into the cores of large bones, these air sacs are for
the complete separation bet. oxygenated and deox air
Organisms face always the issue of mixing, birds cannot afford that bec. they
need fresh air all the time, they have to be much more effifient at
extracting oxygen from the air
Trachea lungs
Anterior air sacs and posterior
Particle cycle of breathing, takes two inspiration rounds and expiration rounds
Inspiration 1
Bird opens its nostrils air comes in goes to trachea after entering the
glottis,air that trachea takes in not all goes to the lungs, the rest goes
to the posterior air sacs
Air in the posterior air sacs avascular, air that goes into the lungs there will
be gas exchange, inspiration 1
Expiration 1
Air in the lungs goes out, air coming from the lungs, air in the posterior air
sacs now goes into the lungs, lungs can get oxygen from them,
outward direction , doesn’t flow outward the trachea
Inhalation 2
Bird breathes in again, air comes in, new air, this goes to the same, goes into
the lungs and the posterior air sacs, problem here is there is cold air in
the lungs at that point from posterior airs sacs, there will be mixing, it
will go to the anterior air sacs
Expiration 2
Everything goes out, new air, old air in lungs and old air in anterior air sacs
all go out, very efficient, one rule of thumb, anterior airsacs will
contain old air
Posterior airsacs new air
Anterior always to separate old air
Lungs of birds more active act as pump
A bit more force required
Continuous process
I1
New air goes into the lungs and the posterior airsacs
E1
Old air goes out new air from posterior airsacs bone to the lungs
I2
Have to segregate so it goes to anterior airsacs
Air never goes directly from posterior to anterior
posterior always carrying new air
Anterior always carrying old air
E2
new air goes to lungs then go out
Crosscurrent flow – at an angle,flow of air have series of tubes parabronchi
Series of respiratory that are perpendicular, very efficient, gas exchange at a point of
contact
Mammals
Extensive use of diaghpragm (muscle when contracts it shortens it goes
down it will increase chest cavity volume causing inhalation) and
intercostals
External intercostals pull the ribs outward and upward
Internal intercostals Downward and backward
With alveoli –(bidirectional)
Viscera also assist in respiration
Not reliant
Just accesory
Functional considerations
Types of flow
Ventilation and perfusion rates should be balanced (ratios depend on
ecology) 1:1 terrestrial
Fishes can go as high as 30:1, needed by fishes
Can go if you breathe in actively more increasing ventilation rate, not
very efficient, just wasting amount of air taking in, wasting
when blood is flowing the same rate
Metabolic costs of living in water because denser and less oxygen
more diff. to extract vs air
Regulation of blood pH levels
When have a lot of carbon dioxide – increase the acidity of the blood
need to get enough oxygen when not getting enough oxygen
muscular activity will rely on lactic acid metabolism part of
reason why you get cramps, oxygen debt lactic acid build up
only when not enough oxygen,really need to get better supply
of oxygen, natural tendency of body when tired breathe in
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