L1- Homeostasis, Water and Compartments

Question 1

How water is distributed in body

Answer 1

60% of TBW
Of that : 40% ICF
20% ECF

Question 3

How ECF is distributed

Answer 3

PLASMA 
INTERSTITIAL FLUID (between cells) 
TRANSCELLULAR (between joints, e.g.synovial fl)

Question 4

Turnover of Interstitial fluid- how is it made?

Answer 4

Produced by capillaries- process: ULTRAFILTRATION

Drained into CVS by lymphatics

Question 5

Excess Interstitial fluid results in:

Answer 5

Pitting Odema - swelling and any imprint can be seen on skin

Question 6

Électrolyte concentrations of Na, K, Ca

Answer 6

Sodium: high ECF, low ICF
Potassium: high ICF, low ECF
Calcium: higher ECF, vvvvv low ICF

Question 7

What do these relative concentrations mean?

Answer 7

The way the ions would move if the membrane become permeable
They would move DOWN CONC GRADIENT

Question 8

Excitable tissues def

Answer 8

Ability to receive and respond to nuclei
E.g. Muscles and nerves
Ability to form ACTION POTENTIALS

Question 9

Internal environment=

Answer 9

ECF

Question 10

Homeostasis

Answer 10

Maintaining a constant internal environment

Question 11

Negative feedback loop

Answer 11

Controlled Variable- something that must be regulated 
Sensor/Receptor - can monitor it 
Processor/ Control Centre 
Set point 
Effector Mechanism

Question 12

Receptor

Answer 12

Many def

• specialised cell that can répond ti changes In the internal environment ie. ECF
• protein (special) and can attach to ligand or signalling molecule ( later lectures )

Question 13

Aim of Neg Feedback loop

Answer 13

To restore ten controlled variable back to set point
Set point : what the CV should be
E.g. Body temp 37