Biology

Created by: Emma
Created on: 20-05-13 15:37

Using the mammalian circulatory system as an example, explain how the different cells and tissues enable effective gas exchange. (4)

-Cartilage in trachea holds airways open -Alveolus walls made of squamous epithelium providing short diffusion distance -Goblet cells secrete mucus to trap dust and pathogens -Smooth muscle allows constriction of airways

1 of 5

Describe how the spirometer would be used to measure tidal volume. (3)

-Wear a nose clip -Breathe normally -Measure height of waves from trace -Measure at least three waves and calculate mean

2 of 5

Describe how to measure the rate of oxygen uptake from a spirometer trace. (3)

-Measure the decrease in the volume of the chamber by drawing a line between the tips of two separate peaks -Measure the time taken for this -Divide volume by time

3 of 5

Explain why the curve for foetal haemoglobin is to the right of the curve for adult haemoglobin. (3)

-Foetal haemoglobin has a higher affinity for oxygen -At the same oxygen tension the foetal haemoglobin is more saturated with oxygen because foetal haemoglobin becomes saturated at a lower ppO2 -Placenta has low oxygen tension -At low oxygen tension

4 of 5

Describe how the action of the heart is initiated and co-ordinated

SAN initiates electrical excitation/ wave spreads across the atria wall/ Atria contract in synchronised manner / Delay at AVN/ wave down septum via purkyne tissue in bundle of His/ ventricles contract from Apex/ into pulmonary artery

5 of 5

Other cards in this set

Card 2

Front

Describe how the spirometer would be used to measure tidal volume. (3)

Back

-Wear a nose clip -Breathe normally -Measure height of waves from trace -Measure at least three waves and calculate mean

Card 3

Front

Describe how to measure the rate of oxygen uptake from a spirometer trace. (3)

Back

Card 4

Front

Explain why the curve for foetal haemoglobin is to the right of the curve for adult haemoglobin. (3)

Back

Card 5

Front

Describe how the action of the heart is initiated and co-ordinated

Back

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Biology