Mer Scott
Quiz by , created more than 1 year ago

Objectives: Define ‘homeostasis’ and explain why extracellular fluid (ECF) composition is regulated in multicellular organisms. • Define ‘osmosis’, ‘osmolarity’ and ‘tonicity’ and understand their relevance to cell volume • Understand the basis of the cell’s ‘resting membrane potential’ and appreciate its physiological significance.

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Mer Scott
Created by Mer Scott over 7 years ago
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L2+L3 Homeostasis: Principles and Control

L2+L3 Homeostasis: Principles and Control

Question 1 of 14

1

The homeostatic theory states that every mechanism of the body exists to the constancy of the body's fluid environment.

Drag and drop to complete the text.

    regulatory
    maintain
    internal
    external

Explanation

Question 2 of 14

1

(Select the correct statements.)
ECF composition is regulated in multicellular organisms because:

Select one or more of the following:

  • 1/3 of total body water is in the ECF.

  • Cell membranes are semi-permeable and the concentration of components in the ECF influences the ICF, and so the internal environment of cells.

Explanation

Question 3 of 14

1

Fill the blank spaces to complete the text.

Fill in the normal reference ranges.
- Core body temperature = - degrees celsius.
- Fraction of body water content in ICF = , and so ECF = . (4/5 of this is fluid, 1/5 of this is .)
- Na+ conc. in ECF = - mmol/L.
- Ca++ conc. in plasma = - mmol/L
- Glucose conc. in blood = - mmol/L while fasting, 3.5 - mmol/L non fasting.
- K+ conc. in ECF = - mmol/L.

Explanation

Question 4 of 14

1

Osmosis is the movement of water toward a region of concentration of , or from a high water concentration to a low water concentration.
is a measure of the total number of solute per of solution. For body cells this is 275 - 300 mosmol/L, in the ECF and ICF.
refers to the effect that a solution's osmolarity has on cell .

Drag and drop to complete the text.

    high
    low
    solute
    particles
    litre
    Tonicity
    volume
    Osmolarity

Explanation

Question 5 of 14

1

Normal RMP (resting membrane potential) is:

Select one of the following:

  • -70mV, if the outside of the cell is taken as 0.

  • -70mV, if the inside of the cell is taken as 0.

Explanation

Question 6 of 14

1

The main determinant of RMP (resting membrane potential) is:

Select one of the following:

  • K+, as it has the highest permeability of ions.

  • Ca++, as it controls electrical impulses and therefore contractions in muscles.

Explanation

Question 7 of 14

1

The RMP of cells remains constant.

Select one of the following:

  • True
  • False

Explanation

Question 8 of 14

1

Which statement about reference (normal) ranges is incorrect?

Select one of the following:

  • Reference range values are specific to age group, and values within two standard deviations of the mean are considered normal.

  • By chance, 5% of tests outside this range are from healthy people.

  • Intra-individual variation is normal, but inter-individual is not.

  • Both inter-individual and intra-individual variation are normal.

Explanation

Question 9 of 14

1

Choose the correct statements about feedback systems.

Select one or more of the following:

  • Positive feedback systems are the most helpful to maintaining homeostasis.

  • Negative feedback systems oppose change to regulated variables.

  • Feed-forward system responses can be behavioural or physiological.

  • The sensor and integrator of a system can be the same cell.

  • A good example of a negative feedback system is childbirth, specifically oxytocin release due to stretch which triggers more contractions.

Explanation

Question 10 of 14

1

Choose the two physiological communication pathways, and their appropriate timings.

Select one of the following:

  • Neuronal for quick responses, hormonal for slow responses.

  • Neuronal for slow responses, hormonal for quick responses.

  • Feed-forward for quick responses, feedback for slow responses.

Explanation

Question 11 of 14

1

Which method of heat loss is still effective when the environment is hotter than the body.

Select one of the following:

  • Evaporation

  • Radiation

  • Convection

  • Conduction

Explanation

Question 12 of 14

1

allows more blood to the skin and so allows more heat . diverts more blood to the visceral organs and so aids heat .

Drag and drop to complete the text.

    Vasodilation
    Piloerection
    loss
    retention

Explanation

Question 13 of 14

1

In anatomical position the palms face backward.

Select one of the following:

  • True
  • False

Explanation

Question 14 of 14

1

Which statement is false?

Select one of the following:

  • Anterior is opposite to superior.

  • Inferior means below something, superior means above something.

  • Medial means closer to the saggital median line, lateral means further away from it.

  • Distal is opposite to proximal.

  • Superficial means closer to the surface.

Explanation

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