Lecture 7 Flashcards
What consist of extracellular fluid
Plasma in the blood vessels and interstitial fluid Between lymphatic capillary and the blood capillary
What is the intracellular fluid
It’s is the fluid within the calls
What is the interstitium
Gel like fluid between the capillary and tissue
What is supporting the interstitium
Supported by collagen fibre and proteoglycan filaments (made of hyaluronic acid and protein that form a mat of fine filament)
What fast is the diffusion between the gel in the interstitium
95% - 99%
How much free fluid are found in vesicles and revulets
1%
What makes up the interstitium
Free fluid vesicles, revulets of the free fluid, proteoglycan filaments, collagen fibre bundles
How much volume does the interstitium occupy in a body
1/6
What is the weight of the total body water(TBW)
60%
How much water are in the extracellular
1/3 of TBW
What are the extracellular parts
Plasma, interstitial fluid
How does water travel to the intracellular fluid
From plasma > capillary > interstitial fluid > cell membrane > intercellular fluid
How much water from the extracellular are in the interstitial
3/4
How much water from the extracellular are in the intravascular
1/4
What does the body of water transport
Water, solutes, nutrients and gases
How does the body of water transport one place to another
Diffusion and osmosis driven hydrostatic and oncotic
How much of the Total body water (TBW) are in the intracellular
2/3
How much water is loss for human per day
<5%
How much water is lost when there is dry mucous membranes
5%
When do you start to have reduced skin turgor
6-8%
When does your heart rate start to increase due to the lack of water
8-10%
What affects diffusion
Uncharged solute and charged solute
How does uncharged solute affect rate of diffusion
It is affected by the concentration gradient difference
Net diffusion = flux or flow (J)
How does charged solute affect rate of diffusion
Diffusion accelerates when different charge are on each side. Reduced when they have the same charge
What does osmosis mean
A form of diffusion when water flow across a membrane that is permeable to water but no to solutes
What is the Fick’s Law expressed as
Surface area of the membrane * difference in concentration across membrane/length of the diffusion path
What does oncotic or colloid pressure mean?
Osmotic pressure generated by large molecules such as plasma proteins which cannot pass across the membrane
How does water molecule pass through calls
Passes through lipid belayer of cell membrane, also passes through channels (aquaporins) in cell membrane
What does water ’follows salt’ mean
It means that water will flow through the permeable membrane towards the side with salt because the concentration of water will be lesser there due to the salt
Which ion have higher concentration in the intracellular fluid compared to the blood plasma and interstitial fluid?
[K+] have higher concentration, 120 - 140 mM compared to 4.7mM
Which ion have higher concentration in the extracellular fluid than in the intracellular fluid
[Na+], 153mM compared to 10-15 mM
What is the difference in osmalality for extracellular fluid and intracellular fluid
The same, 290mOsm/kg
What is Mole
Unit of mass of 6.022 x 10^23 atoms of molecules
What is molarity
Molarity is the concentration of a solute or solvent within the mixture/ solution.
Concentration (g/L)/molecular weight
What is the physiological saline concentration
9 g/L
What is molality
Mole of solute(no. Of particles)/ Kg solvent
What is the molality of physiological saline
0.15moles/1kg or 0.15 molal
What is osmolarity
Osmotic concentration
Concentration of particles/L in solution and is independent of the size or weight of the particles.
= no. Of particles(or mole) x concentration /L (Osm/L)
What is osmalality
Concentration of particles/kg (Osm/kg)
Where is osmolarity approximates Osmolality
When the solution are diluted: mOsm/L ~ mOsm/Kg
What is the concentration of NaCl in the red blood cells
0.9%
What is tonicity
Measures the osmotic pressure gradient
What are the different ways to describe its tonicity
Isotonic, Hypertonic and hypotonic
What does Isotonic mean
The concentration of solution on both side of the membrane is equal and no water movement occur
What is haemorrhage tonicity
Isotonic
What is hypertonic compartment or solution
When the osmotic pressure of the solution outside the cells s higher than the osmotic pressure inside the cells , the solution is hypertonic
What does hypotonic compartment affect cells
Net movement of water out of cell and cell shrinks cremates, happens when there are loss of fluid through vomiting and diarrhoea
What is hypotonic compartment or solution
When the solution outside of the cells has a lower osmotic pressure than the cytoplasm of the cells, the solution is hypotonic with respect to the cells
What happen to cells when affected by hypotonic compartment
Water moves into cell & cell expands
What is an example of hypotonic
Haomolysis
What makes up the circulatory system
Heart, arterial system, venous system, lymphatic system
What is the role of the heart
Cardiac muscle contracts to pump blood around the body
What is the role of the arterial system
Distributes blood from the heart to the capillaries
What is the role of the venous system
Acts as a reservoir for blood and returns blood to the heart
What is the role of lymphatic system
Returns proteins and fluids back to blood
What is the function of the circulatory system
- Exchange of substances with environment
- Transport of substrates and
O2 to cells - Remove all of metabolites and CO2 from cells
- Themoregulation
- Immune cells and mediators
What is the function of Aorta
25mm, pulse dampening and distribution
Function of Large arteries
1.0 - 4.0mm, distribution of arterial blood
Function of Small arteries
0.2 - 1.0mm, distribution and resistance
Function of Arterioles
0.01 - 0.2mm, resistance (pressure & flow regulation)
Function of capillaries
0.006 - 0.010m exchange
Function of venules
0.01 - 0.20mm, Exchange, collection and capacitance
Function of veins
0.2 - 5.0mm, Capacitance function (blood volume)
Function of Vena Cava
35mm, collection of venous blood
Which blood vessels have the ability for capacitance?
Veins, venule and vena cava
What is the capillaries wall made of
A single single layer squamous endothelial cell (~2um thick)
How far are capillaries away from every cell in body
30 - 100 um distance
What is the function of precapillary sphincters
Controls blood flow to capillary bed
What Metarteriole is
It connects arteries to capillaries
What tissues have the highest density
Muscles and glands
What tissues have the lowest density
Subcutaneous and cartilage tissue
What are the types of capillaries
Continuous, fenestrated, sinusoidal (discontinuous capillary), nonbrain systemic capillary and brain capillary
Where are continuous capillary located
Muscle, skin, lung, fat, connective tissue
What are the characteristics of continuous capillary
Contain narrow junctions (clefts) & small, coated pits (caveolae) allowing hydrophilic molecules to pass
Where are fenestrated capillary located
Kidneys, intestines, endocrine glands, joints
What are the features of fenestrated capillary
Contain pores and fenestrae - permeable to small molecules
What structures are there in the continuous capillary
Basement membrane, intercellular junction, coated pits, vehicle, endothelial cell
What structures are in the fenestrated capillary
Fenestrae, thin diaphram covering fenestra, endothelial cell, basement membrane
What are the structures in the sinusoidal (discontinuous) capillary
Large fenestration, gaps
Where are discontinuous capillary located
Bone marrow, liver, spleen
What are the features of discontinuous capillary
Wide gaps between endothelial cells - permeable to large molecules
What are the features of neural capillary
Endothelial cells fused together by tight junction and covered by thick basement membrane and astrocyte processes. Water diffuses, solutes require specific transport
Where are the neural capillary located
Brain
What is hydrostatic force
Pressure due to the fluid in vessels
What types of vessels
Closed vessel with distensible walls, leaky vessels
What is closed with distensible walls
The walls bulge when the pressure is high, in the aorta, the smooth muscle and connective tissue dampen the pulses generated by the beart
What is a leaky vessel
Fluid forced through gaps faster than diffusion, in capillaries- hydrostatic pressure drives bulk flow
What are the types of movement of substances across capillary walls
- Diffusion
- Transcytosis or pinocytosis
- Bulk flow via starling’s forces - driving force
How does substance diffuse across capillary walls
- Between cells
- pores or channels (aquaporin), clefts ,fenestration
- lipid soluble molecules can cross endothelial cell membranes
How does transcytosis or pinocytosis move substance across capillary walls
Movement of macromolecules across cells in vesicles
how does bulk flow via starling’s force - driving force move substance across the capillary wall
- Bulk flow of fluid through water filled channels in capillary wall
- fluid transfer of water and dissolved substances across capillaries depends on net hydrostatic and osmotic
How does starling’s forces work
It moves the blood by hydrostatic pressure differences, reabsorption driven by colloid/ oncotic osmotic pressure differences
Why does capillary have higher colloid or oncotic osmotic pressure
Proteins cannot diffuse across capillary walls and remain higher in plasma than interstitial fluid producing a colloid or oncotic osmotic pressure for fluid reabsoprtion.
What is the Net filtration pressure (NFP)
Is the difference between forces driving fluid from the capillary to interstitial fluid and forces driving fluid from interstitial fluid in the capillary
What pressure are present in the capillary
Capillary pressure (Pc), interstitial fluid pressure (Pif), plasma colloid osmotic pressure (πp) and interstitial fluid colloid osmotic pressure (πif)
What is the formula of NFP
NFP = (Pc + πif) - (Pif + πp)
What does filtration in the blood vessels mean
Filtration refers to the output of the fluid from the capillary to the interstitium
What does absorption mean in the blood vessels
It mean absorbing of the fluid from the interstitium back to the capillary
Where does filtration happen the greatest in?
At the arterial end of the capillary
How much fluid are reabsorbed at the venous ends of the capillaries?
90%
What happens when there is a scratch on the skin
- physical damage of the surrounding cells
- histamine release from cells
- capillary and arterioles dilation (vasodilation)
- local plasma protein leakage
- reduction in oncotic reabsorption pressure
- local oedema
Where does the remaining of the 10% fluid that’s not absorbed go?
It is taken up via the lymphatics and returned to the cardiovascular system
What is the function of the lymphatic system
Act as a tissue drainage system and is responsible for returning excess interstitial fluid back to the venous circulation
What are the 4 things the lymphatic system do
- Controls blood & interstitial fluid volume
- Specific transport systems
- Turnover of extracellular matrix constituent
- Defence system
How does the lymphatic system control blood & interstitial fluid volume
- return excess filtered fluid to blood
- return of leaked protein to blood. (-amount equal to total plasma protein
- Failure can lead to oedema)
What specific transport system does lymphatic system have
Absorption of fat from gut.
Also lipid soluble, vitamins eg A, D, E & K
What turnover of extracellular matrix constituents
Hyoluronan & glysosaminoglycans
How does the lymphatic system help to defend the body
- Immune surveillance
- Lymphocyte recirculation
Where does the lymphatic system collect tissue from
Most organs except the central nervous system, eye and bone
What is the lymphatic system made of
Lined by endothelial cells
What is the starting point of the lymphatic system
Endothelial tubes called initial lymphatics in interstitium
What happens after the starting point (initial lymphatics)
Becomes larger collecting lymphatics
Where are the lymph nodes located along
Along the path of the collecting lymphatics
How does the lymphatic system end
Large lymphatics will ultimately drain into the venou system
Is the pressure in the initial lymphatics high
No, very low
Where does the initial lymphatics collect the fluid
Interstitium
How does initial lymphatics control their valve
It depends on extrinsic tissue which Open and close the inlet valve by skeletal muscle contraction. And also intrinsic smooth muscle contractions
What is the extrinsic lymphatic pump
Extrinsic tissue deformation of initial lymphatics to open and close lymphatics.
Massage lymph downstream into collecting ducts.
Tissue stresses need to be applied
What is intrinsic lymphatic pump
Rhythmic contraction of the lymphatic smooth muscle propels lymph downstream.
The presence of bicuspid valves in the collecting ducts prevent backward flow when the collecting lymphatic is contracting
What does it mean by ‘lymph sucks’
Collecting lymphatic segments with an upstream and a downstream valve and intrinsic smooth muscle to compress the lymphatic lumen are known as lymphangions.
Believed to be important in sucking fluid out of initial lymphatics
Does lymph pass through 1 or more lymph node
Yes, before returning to blood by the thoracic duct (large) or the right lymphatic duct (smalle)
What is the role of the thoracic lymph node
Lymph from the rest of the body enters blood at the junction of the left interval jugular and subclavian veins
What is the role of the right lymphatic duct
Lymph from right side of head and neck, right forelimb and part of the thorax enters blood at the junction of the right internal jugular and subclavian veins.
How does lymphatic system respond to infection
Response result from the entry of infectious microorganisms through breaches in skin or mucous membranes
Where will the antigen be at the lymph node`
Antigen will be taken to draining lymph node via afferent lymphatic
What happens to the antigen in the lymph node?
either free in lymph or after phagocytosis by macrophages and dentritic
Where does immune response takes place
in lymph node
What is efferent lymphatic system
It carries lymph to another lymph node or return to the vein
what is Efferent lymphatic system for
distributes effector cells and antibodies and memory lymphocytes throughout body
What is Oedema
swelling of tissues due to excess fluid
What is the general cause for oedema
decrease plasma protein
increased capillary permeability
increased venous pressure
What is lymphoedema
- lymphatic system not working properly
- lack of skeletal muscle contraction
- blocked or damaged lymphatics
- blocked or damaged lymph nodes
What is the cause of lymphoedema
primary lack of lymphatic vessels
-blocked or damaged lymphatic vessels
