Question

how you ranked the treatments:

1. hypertonic saline 2. isotonic saline 3. hypotonic saline

you have chosen hypertonic saline. predict the effects of your treatment on the following:
blood sodium concentration: initial value 114 (low), decrease, no change, increase
brain matrix pressure: initial value 27 (high), decrease, no change, increase
neuron firing rate: initial value 4.5 (high), decrease, no change, increase
net free water movement: initial value out of vessel, into vessel, in equilibrium, out of vessel

Explanation:

Step1: Analyze blood sodium concentration

Hypertonic saline has a higher sodium concentration. So blood sodium concentration will increase.

Step2: Analyze brain matrix pressure

Hypertonic saline causes water to move out of cells (including brain cells). This reduces brain matrix pressure (as less fluid in brain matrix).

Step3: Analyze neuron firing rate

With reduced brain matrix pressure (less swelling which can affect neuron function), neuron firing rate decreases.

Step4: Analyze net free water movement

Hypertonic saline: water moves into the vessel (as vessel has higher solute concentration initially, water moves to dilute it).

Answer:

Blood Sodium Concentration: Increase; Brain Matrix Pressure: Decrease; Neuron Firing Rate: Decrease; Net Free Water Movement: Into Vessel.