Principles Flashcards
What is the normal osmolarity of body fluids?
~300mOsm/l
What is directly proportional to the rate of diffusion, according to Fick’s Law?
Increased solute concentration gradient Increased membrane surface area Increased lipid solubility Decreased molecular weight Decreased membrane thickness.
What is a cadherin
Links cells together - a type of cell adhesion molecule
What is an integrin
Links the intracellular fluid with the extracellular fluid. A type of cell adhesion molecule.
What are the 3 types of junction between cells?
Gap
Tight
Desmosome
What are the two chemicals invoved in fever generation?
Endogenous pyrogens and prostaglandins
What do iso-, hypo-, and hyper- tonicity do to a cell?
Isotonic: stayss the same volume
Hypotonic: cell swells/bursts
Hypertonic: cell shrivels.
What are the 2 types of carrier mediated transport?
Facilitated diffsion and active transport
Which of facilitated diffusion or active transport requires ATP?
Active transport.
What are the 2 types of active transport?
Primary and secondary
What is primary active transport?
Moves solutes against their concentration gradient.
ATP binds directly to the transporter, providing the energy to move the solute.
What is the pump called in secondary active transport?
The sodium-potassium pump
Whaat are the 3 roles of the sodium-potassium pump?
Maintain the cell volume
Maintain the intra-cellular solute concentrations
Provide the energy for secondary active transport.
Fill the blanks for the sodium-potassium pump:
_ sodium ___, _ potassium ___
3 Na+ out, 2 K+ in
What are the two subtypes of secondary active transport?
Symport and antiport
What’s the different between symport and antiport?
Symport: solute moves in the same direction as sodium
Antiport: solute moves in the opposite direction to sodium
What are the two types of vesicular transport/
Endocytosis and exocytosis
At rest, is there more sodium inside or outside the cell?
OUTSIDE
At rest, is there more potassium inside or outside the cell?
INSIDE
What does Em mean?
Membrane potential
What is the normal resting membrane potential of a cell?
-70mV
What’s the normal restng membrane potential for potassium?
-90mV
What’s the normal resting membrane potential for sodium?
+60mV
What maintains the Em??
The sodium-potassium pump maintains the resting membrane potential.
What is anabolism
Builing things up from smaller subunits
What is catabolism
Breaking things into smaller parts
What do the aplha cells in the islets of langerhans do?
Release glucagon
What do the beta cells in the islets of langerhans do?
Release insulin
What does the brain overwhelmingly rely on for energy?
Glucose
Why is it important to always have glucose in the bloodstream?
Because it is necessary for brain function
What is the definition of hypoglycaemia?
<2.5 mmols of glucose
Which hormones control glucose levels in the absorptive and post-absorptive states?
Insulin in absorptive
Glucagon in post-absorptive
Which hormones control glucose levels in emergency situations? What do they do to them?
Cortisol and adrenaline. Increase glucose levels.
Which hormones control glucose levels in the starved state?
Growth (pituitary) hormone
What is the word for creating more glucose from stores?
Glycogenolysis
What is the word for putting glucose into storage?
Glycogen synthesis
What is the word for making more glucose from scratch?
Gluconeogenesis
Whch transporters increase glucose uptake by the cells?
GLUT4
What does insulin do?
It’s a fed-state hormone which encourages the body to store glucose. It’s anabolic.
Is insulin secretion sympathetic or parasympathetic?
Parasympathetic
Is glucagon secretion sympathetic or parasympathetic?
Sympathetic
What does glucagon do?
Tries to preserve levels of glucose in the blood during hunger. It causes glycogenolysis and gluconeogenesis.
Where does cortisol come from?
The zona fasciculata of the adrenal gland
When are cortisol levels highest?
In the morning
What effect does cortisol have on blood sugar?
Increases glucose levels (it’s a stress hormone)
