For an explanation, see the main splats page
SPLATS about control systems
The principles of control systems
- Homeostasis is a characteristic found in systems that survive: the obvious example is mammalian temperature, but many other things are also finely balanced.
- Effective control in living things relies on feedback systems, where a shortage of an item triggers its production, and an excess stops production in some way.
- Animals have a variety of control systems: nerves carry fast messages, hormones are slow and wide-reaching, pheromones carry signals between individuals.
- There are two kinds of signalling methods within animals like us: target-specific messages are sent by nerves and slower general messages are sent by hormones.
- Many hormone systems are driven by secretions from the pituitary gland, and if indirect influences are included, most hormone systems are pituitary-driven.
- An important male hormone is testosterone and an important female hormone is estrogen, but other hormone is present in small amounts in the other sex.
- The key hormone in blood sugar balance is insulin, which is produced as and when it is needed, in cells in the pancreas called the islets of Langerhans.
- Gonadotrophin is the name given to a group of proteins: human chorionic gonadotrophin is produced by the placenta and in the urine, is a pregnancy indicator.
- Around 170, Galen discovered how nerves operate when he cut into the laryngeal nerve of a pig, after which it continued to struggle, but stopped squealing.
- Nerves communicate at a synapse, where chemicals like glycine and acetylcholine carry a signal from one nerve to another, being destroyed soon afterwards.
- The operation of the nervous impulse can be described as electrical signals, but the operation of the nervous system involves changes in membranes.
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