Practise mammalian coordination questions by comparing nervous and endocrine signalling, tracing action potentials and synapses, and explaining muscle contraction.
Glucagon is released by the alpha ( ) cells of the pancreas when the blood glucose concentration decreases below the set point.
Fig. 6.1 outlines the response of liver cells to glucagon.
Fig. 6.1
State how glucagon reaches the liver cells.
Compare the endocrine and nervous systems in control and co-ordination in mammals.
Outline the role of a chemoreceptor cell in the human taste bud in detecting stimuli and in stimulating the transmission of nerve impulses in sensory neurones.
Fig. 7.1 is a diagram representing a synapse between a chemoreceptor cell from a human taste bud and a dendrite of a sensory neurone.
Fig. 7.1
In an experiment, different concentrations of sodium chloride solution were applied to the microvilli of the chemoreceptor cell. The membrane potential of the chemoreceptor cell and the membrane potential of the dendrite of the sensory neurone were recorded for each concentration.
The resting potential of this chemoreceptor cell is -50 mV and the resting potential of the dendrite of this sensory neurone is -70 mV .
The results are shown in Table 7.1.
Table 7.1
Explain the results shown in Table 7.1.
Describe the differences in structure and function between sensory neurones and motor neurones.