Cell Membrane Transport (Passive & Active) Diffusion, Osmosis, Hydrostatic Oncotic Pressure Colloid
Summary
TLDRIn this video, Nurse Sarah from RegisteredNurseRN.com explains how fluid and solutes move within the body to maintain balance. She covers key concepts like simple diffusion, facilitated diffusion, active transport, osmosis, and the roles of hydrostatic and oncotic pressure. Sarah details how these processes allow substances to move across cell membranes and maintain homeostasis. The video also touches on practical applications in healthcare, such as using IV fluids to correct fluid imbalances in patients. This thorough review provides essential insights into fluid dynamics and cell transport mechanisms.
Takeaways
- 🧬 The human body maintains a balanced homeostatic environment through various transport processes.
- 🫧 Simple diffusion allows molecules to move from high to low concentration without using energy, specifically for small, non-charged molecules like oxygen and carbon dioxide.
- 💡 Facilitated diffusion helps larger or charged molecules move across the cell membrane using carrier proteins, still following a high to low concentration gradient without energy.
- ⚡ Active transport moves molecules against the concentration gradient, from low to high concentration, using energy in the form of ATP.
- 💧 Osmosis involves the passive movement of water through a semi-permeable membrane to balance water concentration inside and outside the cell.
- 🧪 Oncotic pressure (or colloidal osmotic pressure) pulls water into capillaries, driven by proteins like albumin that are too large to exit the capillary wall.
- 🏞️ Hydrostatic pressure pushes water and solutes out of the capillaries into the tissue space through a process known as filtration.
- 💧 In conditions like hypoalbuminemia (low albumin levels), water leaves the blood plasma and can cause swelling as a result of reduced oncotic pressure.
- ❤️ Hydrostatic pressure is created by heart contractions and is strongest in arteries, helping to move blood and nutrients throughout the body.
- 🩺 Osmosis and these fluid transport processes are essential in healthcare, particularly in managing patients with fluid imbalances through targeted IV fluids.
Q & A
What is the primary function of transport processes within the human body?
-The primary function of transport processes in the human body is to maintain homeostasis by balancing fluids and solutes, allowing substances to move in and out of cells effectively.
What is the phospholipid bilayer and why is it important?
-The phospholipid bilayer is a structure found in cell membranes that acts as a barrier, allowing selective movement of substances in and out of cells. It consists of hydrophilic heads and hydrophobic tails, which help control what can pass through the membrane.
What is the difference between simple diffusion and facilitated diffusion?
-Simple diffusion allows small, non-charged molecules to pass directly through the phospholipid bilayer from high to low concentration without energy. Facilitated diffusion, on the other hand, involves larger, charged molecules that require special protein channels to move across the membrane, but it also does not require energy.
How does active transport differ from diffusion processes?
-Active transport differs from diffusion because it moves molecules from low to high concentration, going against the concentration gradient. This process requires energy in the form of ATP, unlike diffusion, which is passive and does not need energy.
What role does ATP play in active transport?
-ATP provides the necessary energy to move molecules and solutes against their concentration gradient during active transport, allowing them to move from areas of low concentration to high concentration.
What is osmosis, and how does it help maintain homeostasis?
-Osmosis is the movement of water through a semi-permeable membrane from areas of high water concentration (or low solute concentration) to areas of low water concentration (or high solute concentration). It helps maintain homeostasis by balancing water levels inside and outside cells.
What can happen to cells if osmosis is not properly regulated?
-If osmosis is not regulated, too much water may enter a cell, causing it to swell and potentially burst, or too much water may leave the cell, causing it to shrink and dehydrate.
What is oncotic pressure and how does it relate to osmosis?
-Oncotic pressure, also known as colloidal osmotic pressure, is the pulling force on water created by proteins like albumin in the blood. It helps maintain fluid balance by pulling water into the capillaries through the process of osmosis.
How does hydrostatic pressure function in the body?
-Hydrostatic pressure is the force exerted by the fluid within blood vessels, created by the heart’s contractions. It pushes water and solutes out of the capillaries into the interstitial fluid, playing a key role in filtration.
How do oncotic and hydrostatic pressures work together to maintain fluid balance?
-Oncotic pressure pulls water into the capillaries, while hydrostatic pressure pushes water out. Together, these forces balance fluid movement, ensuring that water and solutes are properly distributed between the blood vessels and surrounding tissues.
Outlines
🧬 Understanding Transport Mechanisms in Cells
This paragraph introduces the concept of maintaining homeostasis within the human body through various transport processes that balance fluids and solutes. It explains the structure and function of the phospholipid bilayer of cell membranes, highlighting hydrophilic heads and hydrophobic tails. The focus is on different transport mechanisms, including simple diffusion, which allows small, non-charged molecules like oxygen and carbon dioxide to passively move from high to low concentration. Larger, charged molecules use facilitated diffusion, requiring special proteins to move through the membrane.
💧 Osmosis and Water Movement Across Membranes
This paragraph explains the process of osmosis, focusing on the passive movement of water across a semi-permeable membrane. Water moves from areas of high water concentration to low, or from areas of low solute concentration to high, aiming to equalize concentrations. The example of how water movement is influenced by solute levels inside and outside the cell illustrates potential outcomes like cell swelling or shrinking. It also mentions how medical interventions can use this principle to treat patients with fluid imbalances, such as rehydrating or dehydrating cells based on the patient's condition.
💪 Oncotic Pressure: The Role of Proteins in Fluid Balance
This section focuses on oncotic pressure, specifically the role of albumin in pulling water across capillary walls into blood vessels. It explains that albumin, a large protein in blood plasma, creates osmotic pressure by attracting water, keeping it inside the vessels. The paragraph highlights the clinical significance of hypoalbuminemia, a condition where low albumin levels reduce oncotic pressure, causing water to move into surrounding tissues and leading to swelling. The interplay of albumin and water in maintaining fluid balance is emphasized.
💦 Hydrostatic Pressure: Pushing Fluids Across Capillaries
This paragraph explains hydrostatic pressure as the force exerted by blood within the capillaries, pushing water and solutes into the interstitial space (filtration). It contrasts this with oncotic pressure, which pulls water back into the vessels. Hydrostatic pressure originates from heart contractions and is highest in arteries, pushing nutrient-rich blood out to tissues, and lowest in veins, where it helps return deoxygenated blood to the heart. The combination of hydrostatic and oncotic pressures maintains fluid movement and balance across capillaries.
Mindmap
Keywords
💡Homeostasis
💡Phospholipid Bilayer
💡Simple Diffusion
💡Facilitated Diffusion
💡Active Transport
💡Osmosis
💡Hydrostatic Pressure
💡Oncotic Pressure
💡ATP
💡Albumin
Highlights
The human body maintains a homeostatic environment to balance fluids and solutes using various transport processes.
There are two main types of diffusion: simple diffusion and facilitated diffusion.
Simple diffusion requires no energy and allows molecules to move from a high concentration to a low concentration through the phospholipid bilayer.
Tiny, non-charged molecules like oxygen and carbon dioxide move through the cell membrane using simple diffusion.
Facilitated diffusion, unlike simple diffusion, uses carrier proteins to move larger or charged molecules like glucose and ions across the membrane.
Active transport moves solutes from a low to high concentration, requiring energy in the form of ATP.
Osmosis is the passive movement of water through a semi-permeable membrane, balancing water and solute concentrations.
Water moves from areas of low solute concentration to areas of high solute concentration during osmosis, driven by osmolarity differences.
Osmosis can lead to issues such as cell swelling and rupturing, or cell dehydration, depending on solute concentration.
Osmosis is used in healthcare to rehydrate or dehydrate cells in patients with fluid volume imbalances.
Hydrostatic pressure pushes water out of capillaries into tissue spaces, while oncotic pressure pulls water back into capillaries.
Oncotic pressure is created by proteins like albumin, which attract water through osmosis and keep it inside blood vessels.
Low albumin levels, such as in liver or kidney disease, reduce oncotic pressure, causing swelling as water escapes into surrounding tissues.
Hydrostatic pressure is generated by the heart and is highest in the arteries, where it drives filtration to deliver nutrients to tissues.
The balance between hydrostatic and oncotic pressure ensures proper fluid distribution between blood vessels and tissues.
Transcripts
hey everyone it's nurse Sarah with
registered nurse rn.com and in this
video I'm going to talk about how fluid
and solutes move within our body so
let's get started the human body likes
to maintain a homeostatic environment to
make sure that our fluids and solutes
are equally balanced and to do this it
has different types of transport
processes that allow this to be achieved
so in this review I'm going to be
talking about the two types of diffusion
known as simple diffusion and
facilitated Fusion along with osmosis
and active transport and hydrostatic
pressure and oncotic pressure also known
as colloidal osmotic pressure first
let's talk about the processes that move
substances within the cell specifically
that cell membrane here you're going to
see a phospholipid bilayer that is found
within the cell membrane and this
phospholipid bilayer acts as this medium
to really allow substances to flow in
and out of the cell so here you see the
circular yellow little balls those are
known as the hydrophilic heads and then
coming off those heads are the
hydrophobic tails and they really just
come together to help form this barrier
that separates the extracellular part
the outside of the cell from the
intracellular part the inside of the
cell and then scattered within this
membrane are these channels carrier
proteins now one thing I want you to
remember about this bilayer is that it
is very particular it only allows
certain substances to go in through
certain processes so really based on the
size and if this solute is charged will
depend on how it's going to enter or
exit the cell so first let's talk about
simple diffusion simple diffusion is
just as its name says it's a very simple
process because it requires no energy
from the cell and it's a passive form of
Transport so what happens with this
process is that molecules hence solutes
are going to move from a high
concentration to a low concentration so
here we see outside of our cell a lot of
solute there's a high concentration of
them and according to simple diffusion
they are just going to easily diffuse
hence move through that phospholipid
bilayer to the inside of the cell where
there's not a lot of solutes until
homeostasis has been achieved so this
mass movement will continue until we
have equilibrium where we have a balance
of these solutes now an important thing
to remember about simple diffusion is
that only tiny non-charged molecules are
going to be able to go straight through
this phospholipid bilayer so we're
talking about things like oxygen carbon
dioxide and so forth now a bigger
charged polar molecules want to move in
and out of the cell they need to do it
through a different process known as
facilitated diffusion and facilitated
diffusion is very similar to simple
diffusion but with facilitated diffusion
it's going to use these special help
proteins that are found within that
phospholipid membrane to move these
solutes molecules to and from the cell
so again these molecules hence solutes
are going to go from a high
concentration to a low concentration
it's going to go down that concentration
gradient it's a passive form of
Transport requires no energy but it's
going to allow big molecules that are
charged and polar to move to and from
the cell they just can't go straight
through the phospholipid bilayer so we
can move glucose and ions to and from
the cell now we have a different type of
transport that's sort of going to do the
opposite of what diffusion did because
with diffusion we went from high to low
concentration we were going down the
concentration gradient it was a very
simple process we didn't have to go
against it but sometimes our body wants
to move against this concentration
gradient and wants to go from a low
concentration to a high concentration
and this is where where active transport
comes into play so with active transport
there's going to be the movement of
molecules and solutes from a low
concentration to a high concentration
through these special proteins found
within that phospholipid bilayer but
it's going to use energy in the form of
ATP so here we have our phospholipid
bilayer notice on the inside of the cell
we don't have a lot of solutes but on
the outside of the cell we have a lot of
them so with this transport process we
want to go from low to high so we're
going against that concentration
gradient rather than just down the
concentration gradient so when we go
against it it requires effort a lot of
energy so this is where we utilize ATP
so in order to move this molecule from
the inside the cell to the outside of
the cell it's going to flow through this
special protein Channel but ATP is going
to help energize this process and we're
going to be able to flow to that higher
concentration now let's take a look at
all osmosis so with osmosis we're
talking about the movement of water
water is going to move through a
semi-permeable membrane that is only
permeable to water and nothing else and
it's going to do this through a passive
process it's a passive form of Transport
requires no energy and the whole goal of
Osmosis is to achieve homeostasis in the
terms of water it water wants to shift
around until we've equaled out the
concentration of water inside and
outside the cell and we've equaled out
that solute concentration so whenever
you're trying to understand osmosis you
can look at it one of two ways one way
is that you can remember that water will
move from a high water concentration to
a low water concentration or water is
going to move from a low solute
concentration so the solutes hints the
dissolved substances that are in that
water are low and that water wants to
move to a fluid hence water situation
where the solutes are high it has a high
osmolarity of is a lot of solutes in it
so water is attracted to solutes hence
water is attracted to sodium got a lot
of sodium on board it's going to draw a
lot of water in so those are two ways
you can look at osmosis and when we're
talking about a cell we're talking about
water moving in and out of the cell and
it all really depends on that solute
concentration whether it's High inside
of the cell or outside of the cell so
let's look at this illustration here on
the outside of this our extracellular
part of our cell there is a lot of water
but there's not a lot of solute so it
has a low osmolarity on that
extracellular fluid but on our inside of
the cell notice there's a lot of solute
but not a lot of water so it has a high
osmolarity in there so according to
osmosis effortlessly no energy needed
that water wants to achieve some
homeostasis it's really salty or high
osmolarity inside of that cell so that
water is going to be drawn through a
semi-permeable membrane and it's going
to go and enter in to that cell until
it's tried to equal out osmolarity
inside and outside of the cell and
whenever that's achieved osmosis will
cease now some problems that can arise
whenever fluid does move in this
Direction with osmosis because we have a
cell that has such a high osmolarity is
that too much water can go inside that
cell and it can cause it to swell and
rupture and the flip side can happen
let's say that inside of the cell had a
low osmolarity but the outside of the
cell had a high osmolarity had a lot of
solutes but and it didn't have a lot of
water well too much water can leave that
cell and go in the opposite direction to
extracellular fluid and we could
dehydrate that cell and shrink it now
the neat thing about this osmosis
process is that in healthcare we can
actually use this to benefit our patient
because sometimes patients come in with
fluid volume deficit or fluid volume
overload and they need certain fluids to
help correct that imbalance and we can
manipulate this osmosis process with
those fluids based on the solute
concentration of these fluids to help
either rehydrate that cell or dehydrate
that cell depending on what's going on
with that patient so if you'd like to
watch more in-depth review over IV
fluids and this whole osmosis process
you can check out these videos up here
so we just reviewed how certain
transport processes move fluid and
substances to and from that cell through
that cell membrane now let's look at
some processes that move fluid from the
capillaries to the inner stitchum also
known as the tissue Space by talking
about hydrostatic and oncotic pressure
hydrostatic pressure and oncotic
pressure are two pressures that
literally work the opposite of each
other but they work beautifully together
to help maintain fluid going across our
capillary wall into our inner stitching
our tissue space with oncotic pressure
it's going to pull water across that
capillary a wall and hydrostatic
pressure is going to push water across
that capillary wall so first let's talk
about oncotic pressure so oncotic
pressure you may hear also referred to
as colloidal osmotic pressure so if you
also hear that term as well that's what
it's talking about because sometimes I
can get a little confusing and this is
that pulling force on water created by
proteins specifically the protein
albumin which is known as a colloid and
a cool thing about albumin is that a lot
of it hangs out in our blood plasma and
it is way way too big to pass through
that capillary wall so it just hangs out
there in that blood plasma and that
intravascular space in high
concentrations and whenever it does this
by hanging out in high concentration it
creates an osmotic pressure which pulls
water through a process known as osmosis
and we just talked about osmosis and we
know that osmosis occurs because water
loves to be where there's a high
concentration of something hence solutes
and in this case we're talking about
albumin so there's a lot of albumin
hanging out in this capillary wall which
is going to result in water being pulled
in so water is going to stay inside that
capillary which is what we usually want
so again just to drive home that point
let's look at this illustration we have
this example of a capillary and in white
you see all these colloids since album
and the proteins hanging out within this
vessel and it's highly concentrated so
what it's going to do is it's going to
pull water from that surrounding area
that interstitial area with the fluid in
there and it's going to cause water to
stay inside that vessel and the reason
it's doing that is because there's a
high concentration of the albumin inside
that vessel it causes osmotic pressure
to occur which is going to pull water in
there and water is going to stay inside
that vessel hence our capillary now
sometimes problems arise in some
patients where they don't have enough of
this albumin in their blood plasma and
they're experiencing a condition known
as hypoalbum anemia and this can happen
in cases of liver or kidney failure
because your liver makes albumin so you
just don't have enough in your blood or
the patients let's say had severe burn
so we've dropped those levels so what do
you think is going to happen if you
don't have enough albumin in your blood
plasma well your oncotic pressure is
really going to be affected you're not
going to have a lot of it because
there's not enough of it hanging out in
the blood to create that pressure so
instead water is going to leave that
blood plasma go into that interstitial
space and we're going to experience
swelling now let's talk about
hydrostatic pressure so this is the
opposite of oncotic pressure because it
creates a pushing effect on water across
that capillary wall and in other words
really what hydrostatic pressure is is
it's the pressure or force of a fluid
inside a restricted space so in our body
when we're trying to think of that the
restricted space is going to be our
blood vessels hensor capillaries and
that fluid is going to be our blood so
what happens is that this pressure is
created somewhere and it's created by
our heart so our heart contractions
create hydrostatic pressure and
hydrostatic pressure varies throughout
your circulatory system it's really high
in the arteries and we need it to be
high in the arteries because your
arteries take that fresh oxygenated
nutrient-rich blood it needs to push it
out throughout your body so we need
hydrocy pressure to be high but as we
get closer to the venous system it gets
lower because the venous system's job is
to take that used blood back to the
heart so we can make it better again
give it more nutrients so whenever
you're looking at the capillary and
you're trying to figure out where these
pressures are highest on the end of the
arterial part of the capillary is where
the hydrostatic pressure is the highest
versus where it's the lowest which is
the venous in of the capillary and the
whole goal of hydrostatic pressure is
that it needs to create a process known
as filtration because we need to get
this water and solute out of the
capillary into their interstitial fluid
so we can go and do its thing and then
come back to us so what hydrostatic
pressure does is it's that pressure that
pushes that water and solutes out of the
capillary into the interstitial fluid
which is again known as filtration so as
you can see with these two processes
oncotic pressure and hydrostatic
pressure how our body needs them to work
we have one that's going to push out the
water in the nutrients which is
hydrostatic pressure and then we have
the other oncotic pressure which is
going to pull it and keep it inside the
vessels okay so that wraps up this
review and if you'd like to watch more
videos in this fluid and electrolyte
series don't forget to check out the
link in the YouTube description below
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