L1 Flashcards
What is the hierarchical organisation of a body?
What are the systems in a body? Give their functions.
Which systems play a regulatory role?
Nervous system, endocrine system and immune system are particularly important in playing the regulatory role.
What are the four types of dynamic interactions in a body?
Dynamic interaction: (1) Spatial; (2) Temporal; (3) Quality; (4) Quantity.
What are the four ways of signal in a body?
(1) Chemical signals
a. Endocrine (Hormone)
Long distance regulation. Hormone transported by bloodstream to regulate the body.
b. Paracrine
Short distance regulation. Produce chemicals (e.g. growth factors and clotting factors) that act on neighbouring cells.
c. Autocrine
Short distance regulation. Produce chemicals that act back on its own.
(2) Neural (Electrical) signals
What is the composition of body fluid?
What are used to measure extracellular fluid volume and plasma volume respectively?
Inulin is used to measure extracellular fluid volume. Albumin is used to measure plasma volume.
What are osmolarity and osmolality? How to calculate plasma osmolality?
Osmolality – amount of substance per unit mass of solvent.
Osmolarity – amount of substance per unit volume of solvent.
Plasma osmolality = 2[Na+] + [K+] + [urea] + [glucose]
What is the predominant cation in interstitial fluid? State its total body stores.
Predominant cation in interstitial fluid is sodium.
Total body stores of Na+ = K+ = 3000 mmol
State the relation between K+ and H+ concentration and why.
K+ and H+ concentrations often rise and fall together. When H+ concentration rises, influx of H+ into the cell occurs in exchange for K+ efflux out of the cell.
State how to calculate efficiency.
Efficiency = Correction/Error
Negative sign must be given!
State three types of feedback mechanism and state an example for each.
Negative feedback mechanism (to promote stability)
Positive feedback mechanism
Feedforward control
State the importance of positive and negative feedback respectively.
PF to reinforce an action for survival or beneficial purposes
NF to promote a constant environment for cell metabolism
