2. Body Fluids & Membrane Transport Flashcards
State the composition of the human body for a 30 year old 70kg male
18 percent fat
22 percent lean body mass
60 percent water
What percentage of your body composition is water
60 percent is water, approx 42 litres.
What is the total body water comprised of, and how many litres make up each part.
25 litres is Intracellular fluid
17 liters is extracellular fluid.
What is the Extracellular fluid made up of.
13 litres is Interstitial fluid
3 liters is plasma
1 liter is transcellular fluid.
How many liters of interstitial fluid do we have
13
How many liters of plasma do we have
3
Give examples of some transcellular fluids
Cerebrospinal fluid
- Urine
- GI secretions inc. saliva, gastric juice, pancreatic juice, bile and sweat.
- aqueous and vitreious humours.
- synovial fluid.
How many litres of transcellular fluid do we have?
1 litre
Describe the ion concentrations of the Blood Plasma
Na+= 142mM
K+ = 4.4mM
Cl- = 102mM
Protein =1mM
Low K+
High Na+
High Cl-
1mM protein.
(high/low compared with Intracellular fluid)
What is the osmolality of the Blood plasma
290 mOsm
Describe the relative protein concentrations in the E.C.Fs (the blood plasma, and interstitial fluids, transcellular fluid) compared with the I.C.F intracellular fluids
Blood has 1mM protein
Interstitial fluid has no protein
Intracellular fluid has 4mM protein
Transcellular fluid has variable protein concentration
Which fluid has the most protein
The intracellular fluid has 4mM protein.
Describe the ion concentrations of the Intracellular fluid
High K+
Low Na+
Low cl-
High protein [4mM]
Intracellular fluid has less sodium E.C.F but more potassium than the extracellular fluids.
Where is the concentration of potassium ions highest
In the intracellular fluid.
Give the osmolality of the Extracellular fluid
290 mM
Give the osmolality of the intracellular fluid
290 mOsm
What are the ion concentrations of the transcellular fluid. And what is the osmolality of transcellular fluid
Variable.
Variable Osmolality
State three key features of the Plasma membrane
Highly Selective permeability
lots of transport proteins for uptake and removal of specific solutes
vital for regulation for the intracellular environment
Describe the permeability of the cell membrane
phospholipid bilayer is impermeable to ions and polar molecules
Describe the three categories of transporter proteins
Channel protein
Carrier Protein
Pump
What are the functions of the membrane?
- Physical Isolation = separates cytoplasm from extracellular fluid.
- Regulation of Exchange with the Environment
- Sensitivity to the Environment
- Structural Support
What is Glycocalyx?
Glycocalyx is a glycoprotein and glycolipid covering that surrounds the cell membrane of some cells.
Membrane Carbohydrate
4 Functions of glycocalyx
- Lubrication and Protection
- Anchoring and Locomotion
- Specificity in binding
- Recognition of glycoproteins and glycolipids
Define Channel - Mediated Diffusion
Non-lipid soluble molecules ands water-soluble compounds, must pass through a membrane channel. They are created by transmembrane proteins.
Describe the Capillary endothelium
- Very thin layer of cells lining blood vessels
- Highly permeable in some organs, not in others (e.g. brain)
- Important role in regulation of the interstitial fluid
- Fluid is pulled through by colloid osmotic pressure
- Fluids permeate through this under hydrostatic pressure
- Separates the plasma from the interstitial fluid
- Very leaky
Describe the Epithelia
- Layers of cells covering internal and external surfaces of organs and tissues
- Protective/barrier function
- Important roles in absorption and secretion
- Separate transcellular fluid from the interstitial fluid
- These cells tend to absorb and secrete
- Joined by tight junctions to prevent leakage between cells
Describe Integral Proteins
- Transmembrane proteins.
- Apart of the plasma membrane proteins structure
- Can’t be separated from it without damaging the membrane.
Describe Peripheral Proteins
Bound to the inner or outer surface of the membrane and are easily separated from it.
Describe Anchoring Proteins
Attach plasma to other structures and stabilise its position.
Attach plasma to structures and stabilise its position.
Describe Recognition Proteins
Identifiers, for cell , e.g. immune system.
Glycoproteins are important recognition proteins
Describe Receptor Proteins
They are in the plasma membrane
Sensitive to the presence of extracellular ions or molecules called ligands.
Describe Channel Proteins
Permit water and small solutes to move across the membrane.
Some channels are gated, because they open and close to regulate passage of substances.
Describe Carrier Proteins
They bind solutes and transport them across the membrane. (may require ATP)
Define Osmotic Pressure
Osmotic Pressure is the indication of force with which pure water moves into that solution as a result of its solute concentration.
What are Aquaporins?
Abundant water channels in cell membranes. They exceed the number of solute channels, through which water can also pass. = higher permeability for water than for solutes.
What happens to RBCs in an isotonic solution?
In an isotonic saline solution, no osmotic flow occurs, and the red blood cells appear normal in size and shape.
What happens to RBCs in an hypotonic solution?
In a hypotonic solution, the water flows into the cell. The swelling may continue until the plasma membrane ruptures, or lyses.
What happens to RBCs in an hypertonic solution?
In a hypertonic solution, water moves out of the cell. The red blood cells crenate (shrivel).
What is a symport/ cotransporter protein?
the common carrier protein (symporter) transports 2 different molecule/ions through the membrane in the same direction.
What is a Antiport/ Exchanger/ Counter transport Protein?
the carrier protein (antiport) transports 2 different molecules or ions through the membrane in opposite directions.
Whats is a Facilitator/ Uniport Protein?
The carrier protein that transports 1 molecule/ion through the membrane
What is Facilitated Diffusion?
Large insoluble molecules passively transported across the membrane by carrier proteins.
Molecule binds to receptor site on carrier protein. The protein changes shape, moving molecule across the membrane.
Number of proteins is the limiting factor. Once proteins are saturated rate of f-diffusion can’t increase.
What is Active Transport?
high-energy bong in ATP provides the energy needed to move ions or molecules across the membrane. It doesn’t depend on concentration gradient.
What happens at the Sodium-Potassium Exchange Pump?
The operation of the sodium–potassium exchange pump is an example of active transport. For each ATP converted to ADP, this carrier protein pump, also called sodium–potassium ATPase, carries 3 Na+ out of the cell and 2 K+ into the cell.
What is Endocytosis?
The movement of relatively large volumes of extracellular material into the cytoplasm by the formation of a membranous vesicle at the cell surface; includes pinocytosis and phagocytosis.
What are the & stages of Receptor Mediated Endocytosis?
- Ligands bind to receptors in plasma membrane, which migrate to the Clathrin-coated pits
- Ligand-receptor areas form deep pockets in plasma membrane surface.
- Pockets pinch off, forming endoscopes known as Clathrin-coated vesicles.
- Clathrin recycles back to the plasma membrane and endosomes fuse with primary lysosomes to form secondary lysosomes.
- Ligands are removed and absorbed absorbed into the cytoplasm.
- The lysosomal and endosomal embraces separate.
- The endoscope uses with the plasma membrane, and the receptors are again available for ligand binding.
Define Pinocytotis
The introduction of fluids into the cytoplasm by enclosing them in membranous vesicles at the cell surface.
Define Phagocytosis
The engulfing of extracellular materials or pathogens; the movement of extracellular materials into the cytoplasm by enclosure in a membranous vesicle.
Define Exocytosis
The ejection of cytoplasmic materials by the fusion of a membranous vesicle with the plasma membrane.
Define Transcytosis
The type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side.
