Bone & Biomechanics 4 Flashcards
What do soft cells need to do?
Maintain their shape as it is needed for their function
How do soft cells maintain their shape?
Water moves into cells by osmosis and osmotic pressure gives soft tissue cells their shape
What is the Intercellular fluid?
Cytoplasm or cytosol
What must be balanced between the ICF and ECF?
Water
How is water lost?
By water vapour at the skin and lungs, faeces, sweat glands and urine
How much water is lost by water vapour at the skin and lungs based on an intake of 2200mL?
1150mL
How much water is lost in faeces based on an intake of 2200mL?
150mL
How much water is lost at sweat glands based on an intake of 2200mL?
variable
How much water is lost through urine based on an intake of 2200mL?
1200mL
What is also found alongside water in the ICF and ECF?
Solutes and ions
What is isotonic?
Occurs when the ICF and ECF solutions are balanced
What is the benefit of the ICF having a larger volume and water content?
If damage occurs to the ECF then it can be fixed by the extra ICF which is present
Which fluid has the larger volume and water content?
Intracellular Fluid
What is hypertonic?
Occurs when water is lost from the ECF and volume is decreased therefore making the solute concentration higher.
What happens when the ECF becomes hypertonic?
An osmotic water shift from the ICF to the ECF restores osmotic equilibrium but decreases the volume of the ICF.
How can dehydration occur?
If continual loss of water from the ECF occurs
What is hypotonic?
When there is too much water in the ECF
What happens when the ECF becomes hypotonic?
Water moves from a low concentration of solutes into the ICF to restore the osmotic equilibrium. This makes the intracellular environment bigger and the cell swells.
Where are ions and electrolytes absorbed?
Across the epithelial lining of the small intestine and colon
Where are reserves of ions found?
Primarily in the skeleton but also in the ICF and ECF
Where does excretion of ions occur?
At the kidneys(primary site) and the sweat glands (secondary site)
What are the main ions needed in the body?
Potassium, Sodium and Calcium
What are examples of excitable cells?
Neurons and muscles
What do excitable cells have?
A membrane potential
What cells also have membrane potential?
Epithelial cells
What does membrane potential rely on?
The distribution of sodium and potassium ions which are obtained from the diet
Where are cations and anions present?
Inside and outside all cells
What is the function of the lipid bilayer with regard to ions?
It is an insulator to prevent the free flow of cations and anions
What does the distribution of ions create and why?
Membrane potential because they are charged
What is the concentration of sodium ions in the ECF?
High
What is the concentration of potassium ions in the ECF?
Low
What is the concentration of sodium ions in the ICF?
Low
What is the concentration of potassium ions in the ICF?
High
What is the average resting membrane potential and what does it mean?
-70mV which means there is a slight negative change inside the cell
Want is the function of the sodium-potassium exchange pump?
It moves and exchanges sodium and potassium against their concentration gradient and therefore uses energy
What is the chemical gradient?
The concentration gradient
What is the electrical gradient?
Gradient formed by distribution of the charge
What is the electrochemical gradient?
The combination of the electrical and chemical gradients
Where does the sodium chemical gradient point?
Into the cell
Where does the sodium electrical gradient point?
Into the cell
Where does the sodium electrochemical gradient point?
Largely into the cell