Biology

Biology

6.5.1 State that the nervous system consists of the CNS, PNS and cell called neurons that can carry rapid electrical impulses.

6.5.2 Draw and label a diagram of the structure of a motorneuron.

6.5.3 State that nerve impulses are conducted from receptors to the CNS by sensory neurons, and from the CNS to effectors by motor neurons.

Resting potential: the difference in chargebetween the inside and outside of the neuron when an electrical impulse is not being propagated. Usually about
-70mb
Action potential: the reversal and restoration of an electrical differencebetween the inside and outside of a nerve cell during propagation of an impulse.

6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron (axon).
* Na + ions- upon stimulation, Na +ion channels open and Na + rushes into the cell.
* K + ions- shortly after Na + rushes in, K + ion channels open and K + rushes out of the cell.
* Voltage gated ion channels - control whenions cross the membrane.
* Active Transport- restores Na + and K + to their original place, via the sodium/potassium pump.
* Changes in membrane polarization- happen in sequence, starting withstimulation of the sensory nerve.
*
6.5.6 Explain the principles of synaptic transmission.
* Ca + influx
* Release, diffusion and binding of the neurotransmitter.
* Depolarization ofthe post-synaptic membrane.
* Subsequent removal of neurotransmitter.

6.5.7 State that the endocrine system consists of glands, which release hormones that are transported in the blood.6.5.8 State that homeostasis involves maintaining the internal environment at a constant level or between narrow limits.
Homeostatic Factors:
1) Blood pH
2) Oxygen and CO2 concentrations.
3) Bloodglucose
4) Body temperature
5) Water balance.

6.5.9 Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms.

6.5.10...