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Transport in Mammals - pt. 1, 1., 2., 3., LORD - left oxy right deoxy,…
Transport in Mammals - pt. 1
transport system in animals
circulation
important to transport oxygen and nutrients to body cells
necessary to transport carbon dioxide and nitrogenous waste away fm cells
for these transports, as the organism evolves, it also evolves fm simple to complex transport system with use of extracellular fluid
fluid is in contact with every cell, flows through the body
the mechanism by which extracellular fluid flows through the body, to transport oxygen and nutrients to body and nitrogen waste and carbon dioxide away fm body is called circulation
all associated organs become a part of circulatory system - called circulatory system organs
varies with respect to complexity
simple in paramecium - invertebrates
because they have a very simple architecture - level of organisation
measure distance between diff parts to surface - very very small
it's so small, that requirements (nutrients and waste transportation) can be easily met by diffusion
so all invertebrates if it has large surface area and short distances (fm external environment) and simple organisation
usually diffusion or active transport (very simple)
large complex organisms
needs elaborate system
need for transport system
as it gets larger
surface area: vol ratio drops a lottt
since surface area drops requirements of organisms can't be met by diffusion
because of such a big decrease
permeability
paramecium in aquatic, so it has everything it needs
but for terrestrial organisms
they can't have an external permeable membrane
since germs can enter
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as organism gets larger and complex
internal distances betweeen organs increases
diffusion alone can't meet demands
high rate of metabolism
lots of energy released as heat for homeostasis
circulating fluids also carry the heat energy
blood vascular system
not all organisms need it
immortal organisms don't need it
eg: flat worms (platyhelminthes), jellyfish (cnidarians)
because---
metabolism rate is less
internal distance is small
high surface : vol
but mammals, birds, amphibians need it
components
4
presence of circulating fluid
some fluids don't circulate - vitreous humour, synovial fluid , aqueous humour
in a constant state of flow in the body
has respiratory pigments
to transport gases
varies with nature of respiratory pigment
eg---
haemoglobin - vertebrates
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haemocyanin - annelids
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haemoerythrin - molluscs/ gastropods
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chlorocuorin - polychaetes
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circulating fluid invariably has respiratory pigment
invariably, must be a pump
to maintain pressure difference
extracellular fluid flows fm high to low pressure
this is the heart - the pump
mechanism by which circulating fluid needs a network of blood vessels
types of vessels
veins
capillaries
arteries
presence of network of fine tubes
carries it to or away
valves
ensure that flow of blood is in one direction
quite important
types of circulatory system
depending on whether blood is flowing through open (sinuses - cavities) or closed areas
two types
open circulatory system
occurence
most abundant in arthropods/ molluscs/ insects
these are the best examples
mechanism
heart is tubular
heart pumps blood at low pressure
pushed into blood vessel, arteries don't break up into capillaries
pumped out of heart into low pressure, then into open spaces
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haemolymph
because blood mixes with lymph (interstatial/tissue fluid)
so the circulating fluid is not blood anymore, it is hemolymph
organs are bathed in this hemolymph fluid
can't call it the blood anymore
has functions
keeps it moist
provides it with nutrients
oxygen
removes waste
nitrogenous waste
serves as a medium for phagocytosis
open circulatory because its in direct contact with body cells
once taken waste fm cells, goes back into the heart
still called hemolymph but its deoxygenated now
features
less energy intense - don't need large amounts of energy
less energy needed to operate
but leads to major disadvantages
not possible to control rate of flow
no way to control rate at which hemolymph flows
moved by contractions of muscles near vessels coz it opens into cavity
artery made of muscles moves it along
closed circulatory system
fm heart pump
into artery - arterioles - capillaries
body cells never come in direct contact with fluids (the blood here)
occurence
annelids and vertebrates
mechanism
no direct exchange between cells
tissue fluid serves as a medium of exchange
there are valves
features
takes up a large amount of energy
energy intensive
because of a very well developed heart pumping high pressure blood
very efficient
heart can pump at high pressures
volume flow can be controlled by
musculature of arteries
pericapillaries
i.e. - the sphincter muscles in capillaries
comparison
characteristics
comparison
occurence
Open - arthropods and molluscs
Closed - annelids and vertebrates
fluid
Open - hemolymph
Closed - blood
pigment
Closed - haemoglobin
Open - hemoerythrin and hemocyanin
to enhance oxygen carrying capacity
nature of flow
Closed - from high pressure in heart
to artery - arterioles - capillaries - veins
closed blood vessels
Open - hemolymph flows fm heart at a low pressure
to artery to sinuses
so flow can't be regulated by ways other than muscle contraction of arteries and valves (basic regulation)
contact between fluid and cells
Open - come in direct contact
tissue and body cells in direct contact
Closed - only in contact with blood vessels
but come in contact with tissue fluid slightly (indirectly)
exchange
Open - taken through hemolymph
Closed - taken through blood
mediums are different
pressure
Open - hemolymph is at low pressure
enters into cavity
heart isn't well developed so speed reduces
Closed - pressure is very high because of well developed heart
heart
different structure
Open - tubular heart
not so well-developed
Closed - 4 chambered heart
very well-developed
similarities
always circulating fluid present
to transport helpful and non helpful materials
like oxygen and nutrients
carbon dioxide and nitrogenous waste materials
types of closed circulation
depending on how many times blood flows through heart
single circulation
fishes
cold blooded
body temp matches temp of surroundings
even though fish are very active, no need to invest energy to receive support, no need to maintain constant temp
nutrients can easily diffuse into the body
so it can get away with single circulation
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heart of a fish
superior - atrium - chamber and inferior - ventricle
atrium receives blood fm sinus venosus
atrium undergoes systole - contract
and ventricle diastole - relax
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flows through fish heart only once
single circulation
2 chambers
double circulation
as it flows to tissues
and
lungs
it flows through the heart twice
diff variations of this
circulation in amphibians
unlike fish
diff - they have 3 chambered hearts
2 superior - atria
1 inferior - ventricle
cutaneous respiration
can breathe through skin
so called pulmo-cutaneous respiration
right receives deoxy
right auricle contract pushed into ventricle
v contracts pushed into gills or lungs and skin to oxygenate
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its not very efficient
deoxy and oxy blood mixes
incomplete circulation - because bloods mix and it isn't efficient
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circulation in reptiles
double circulation - pulmonary and systemic
heart is 4 chambered 2 superior and 2 inferior
not clearly demarcated
partial septum
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oxygenated blood can go into stomach directly
instead of oxy blood going into systemic circulation
kind of incomplete circulation
but not really because there is a partial septum
because they eat a lot of rotten food, putrified, which needs to be digested quick
flows through the heart twice
and because one part for pulmonary and one for systemic
circulation in mammals and birds
deoxygenated blood
right auricle
right ventricle
to lungs
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twice flows through the heart
pulmonary and systemic
double circulation
deoxy to right a
through vena cava
superior (up) - head
inferior (below) - rest of body
right v pushed out
through pulmonary artery
arteries usually take oxy, but this one is deoxy
then pulmonary vein to heart
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why double
passes twice
has one portion for pulmonary and one portion for systemic
blood vessels
purpose of any circulatory system
make sure that blood is transported to all parts of body
while it undergoes changes in pressure and velocity
as the blood is transported
what happens to pressure
pressure is higher in systemic compared to pulmonary
heart always functions like a pumping organ, maintains a pressure gradient
moves fm high to low pressure
but unlike any fluid, it moves through highly elastic and muscular tubes - blood vessels
max blood pressure is felt in arteries
min pressure is felt in veins
capps is little more than veins
changes in velocity
max in arteries - capillaries - veins
slightly more in caps compared to veins
there are changes because change in cross sectional area of tubing
3 types
arteries
away fm heart
towards tissue
carries oxy blood except pulmonary
connects heart and capps
veins
towards the heart
away fm tissues
deoxy except pulmonary
network between capps and heart
capps
to and from heart
connect arteries and veins
smallest diameter
between tissues and heart
valves in the heart
atrio ventricular valves
between auricle and ventricle
2 types
bicuspid valve
left
fm the lungs to the body
tricuspid valve
right
fm the body to the lungs
semilunar valves
crescent valves
pulmonary semilunar valve
moves fm right v to lungs
aortic semilunar valve
fm left v to remaining parts of body (through aorta)
opening of pulmonary artery and aorta
depending of where the blood goes to
hepatic artery
aorta to liver
ileac vein
away fm lower region of body to heart
inferior venacava to right a
renal artery
aorta to kidney
hepatic portal vein fm stomach to liver
begins and ends in capps
vascentric arteries to stomach
brach of aorta
takes to stomach
hepatic portal vein takes these to stomach
every maj organ
superior vena cava
away fm head and brain
top part of body
celiac artery
to stomach
thickness of blood vessels
varies in blood pressure because of distance fm heart
auricle - thin wall - compared to v - thickk
left and right v - left is thicker
because systemic needs more pressure
pulmonary needs less
arteries relatively thicker walls compared to veins
thickest artery is the aorta
artery
description
transport oxy blood swiftly and under high pressure away fm the heart
associated with transport of oxy blood
very high pressure at high velocity
always away fm heart
structure is similar with few diffs
3 imp layers/ like a tunic
tunica intima
innermost
endothelium
made of squamous epithelium
flat cells, fit into each other like a puzzle
comes in direct contact with blood
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depending on where present
tunica media
middle layer
different in arteries and veins and capps
extensively composed of smooth muscles
presence of collagen
elastic fibres
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tunica externa/adventitia
outermost/external coat
composed of white fibrous connective tissues
has blood vessels on it to provide nourishment to the arteries
only this differs in the diff blood cells
characteristics of arteries
deep seated
closest to heart
relatively thick walls
to withstand pressure
during ventricular systole
a lot of pressure
not smooth flow
because of the systole and diastole
so jerky flow
plus composition of artery - causes contraction of artery itself
and muscles around it
120 mm of mercury
16 kPa
ability to resist this much pressure
so it has thick walls and composition of walls
main characteristics - elasticity and strength
2.5 cm diameter
thick when close to heart
diameter of 25 mm
thickness of 2 mm
large diameter and thickness
composition
changes depending on where it is
when near heart - tunica media has more elastic and collagen - less smooth muscles
when away - less elastic - more smooth muscles
capable of stretching and coiling because of pressure
elasticity
presence of elastic fibres
abundance
when ventricular systole, high pressure, if it wasn't elastic, pressure could break open and rupture the arteries
so it needs to stretch when high pressure
arterioles
arteries' fine branches
having a diameter of 10 µm
similar structure of walls
tunica intima, media and externa
highly muscular
less connective
location isn't same
amount of elastic is less, smooth muscles is higher
muscles can contract and relax
so can change the blood pressure
so regulate flow and blood pressure
areas that need more oxygen
eg when you're exercising
blood vessel contracts less blood goes to stomach and relaxes near where needed so more blood goes there
vasoconstriction and vasodilation
when blood enters
was at 120mm (16 kPa)
by now, dropped to 85mm of mercury (11.3 kPa)
diameter
changes because
2 factors
nervous stimulus
influence of hormone
when adrenaline
blood flows to surface so vessels expand - vasodilation
or reduces diameter of arterioles - vasoconstriction
capillaries
closer to cells, arterioles branch
resulting in tiniest and most small tubes, numerous
diameter - 7µm
thickness of 0.2 µm
function
to penetrate each and every tissue
most important
supply blood closest to the cell
delivers as close as possible to cells
less that 0.1 µm between cells and capp
every single cell
tendency to form cappilary bed
network of fine capps
when come closest to cells, form a network of finest of tubes
called capp beds
all subs exchanged happen at the capp bed
in every cell
except cartilage and cornea
max exchange of subs
size
very very small
matches with size of rbcs
rbcs don't easily pass through, they squeeze through
if you increase distance, more energy needed to transfer oxygen
cells try to operate with passive transport
if touching wall, it can diffuse easily
quantity of blood
@ local level
of all stimulus that can affect the volume, etc
it is the partial pressure of co2 and o2
when - co2 high and oxy low - capps undergo vasoconstriction - so less blood flow
when concentration of carb low oxy high - vasodilation
diapedesis
made of squamous epithelium
not continuous (has gaps)
part of the plasma leaks out (needed)
wbcs squeeze out of this too to reach the site of infection
process called diapedesis
goes into tissue fluid
applicable to anything that squeezes out
rbcs and wbcs
but not for leakage of plasma
@ 85mm pressure, blood reaches
readuced to 35mm - 4.7kPa
by the time it reached the end of capp, becomes 10mm - 1.3kPa
120mm - 85 - 35 - 10 over the course of time
venules
till now everything was branching
artery - arterioles - capps - capp beds
now its uniting
formed by fusion / joining of arterioles
when initially formed
closest to capp beds
doesn't have tunica media
as it gets larger and closer to veins
develop tunica media
characteristic of arterioles and venules - same - more muscles and less elastic since less pressure
veins
venules join and form veins
function
like how arteries transport oxy blood
they transport deoxy (except pulmonary)
to take the blood away fm tissues and to heart
drop in pressure
now its 5 mm -
diff between artery vein and capp
most important is diameter of lumen
largest in veins
large lumen so large medium
so tunica media is abundant in smooth muscles and collagen
absence of elastic fibres
problem
because of low pressure,
in lower extremeties of body
could move to limbs and get stagnant there
because of gravity
body can't afford to have this
some deoxy blood could get settled down, but needs to go back
so it is always sandwiched between skeletal muscles
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solved the problem by semilunar valves
comparison between arteries capps and veins
similarities
all transport blood - circulating fluid
all have 3 layers
all have endothelium
basic structure is same - tubular
differences
walls
thickest - arteries - veins - capps - thinnest
elasticity
max in arteries - veins less - capps least
lumen
space inside
diameter
smallest in capp - slightly higher in artery - largest in vein
valves
none in arteries or capps - but present in veins
only in veins
to prevent backflow since low pressure, slow blood
constriction
arteries can recoil and stretch to maintain driving pressure
because of elastic parts
veins and capps cant
since they have less elastic fibres and more smooth muscles
blood
arteries takes it away fm heart, close to cells
veins - away fm tissues, close to heart
capp - to and away fm heart
permeability
arteries are not
veins are not
capps are
they have to for diffusion of gases + very thin wall
pressure
max in arteries - 120 mm
capps - little less - 10-12 mm inside it
veins - 5-10 mm - lowest
not when it starts
so velocity is high, slows, when it comes back, slightly higher
pulse
in arteries - not uniform
jerky because of systole
but veins and capps is less jerky, more smooth
1.
2.
3.
LORD - left oxy right deoxy
afferent - arteries (carry to gills from heart)
efferent - veins (carry from gills to body)
doubt - how arteries if no blood vessels - open circulatory?
pp - bio - 33
doubt - what is vascentric?? celiac?
doubt - large medium imi?
