Endocrine 1 Flashcards
What are the functions of the endocrine system?
- Maintain Internal Homeostasis
- metabolism
- osmoregulation - Regulate growth and morphological change
- Coordinate development
- Coordinate reproduction
- Facilitate behavioural and social interactions
Tropic and Releasing hormones
Primary function is to stimulate release of other hormones
Bilaterians
Animals with bilateral symmetry, including nematodes, insects and vertebrates who developed the internal communication system known as the endocrine system.
Locations of different endocrine glands
- Hypothalamus
- Pituitary
- Target endocrine glands (thyroid, adrenal, gonads, other tissue)
- Others (parathyroids, pancreas, adipose, others)
Starling’s definition of hormone
Chemical messengers which have to be carried from the organ where they are produced to the organ which they affect by means of the blood stream
Early description of diabetes
Describes the discharge of excessive amounts of urine
First description of the hypothalamus and pituitary
The draining route and receptacle, respectively, for mucus passing from the brain to the naopharynx
Berthold’s experiment
In one of the first endocrine experiments ever recorded, Professor Arnold A. Berthold of Gottingen that a rooster’s comb is an androgendependent structure (ca. 1849).
• Following castration, the comb atrophies, aggressive male behavior disappears, and interest in the hens is lost.
• Importantly, Berthold also found that these castration-induced changes could be reversed by administration of a crude testicular extract (or prevented by transplantation of the testes).
Brown-Sequard’s experiment
On June 1, 1889, Brown Sequard reported to Sociète de Biologic in Paris that he had increased his physical strength, mental abilities and appetite by self-injection with an extract derived from the testicles of dogs and guinea pigs
• Although never substantiated, this claim prompted huge interest the field of organotherapy, which still persists today
Claude Bernard
Claude Bernard stated that the endocrine system regulates the internal milieu of an animal. The “internal secretions” were liberated by one part of the body, traveled via the bloodstream to distant targets cells.
Starling on the mechanism of pancreatic secretion
In an anaesthetized dog, a loop of jejunum was tied at both ends and the nerves supplying it dissected out and divided so that it was connected with the rest of the body only by its blood vessels. On the introduction of some weak HCl into the duodenum, secretion from the pancreas occurred and continued for some minutes. After this had subsided a few cubic centimetres of acid were introduced into the enervated loop of jejunum. A similarly marked secretion was produced - Starling: “Then it must be a chemical reflex.” Rapidly. After a few moments the pancreas responded by a much greater secretion then cutting off a further piece of jejunum he rubbed its mucous membrane with sand in weak HCl, filtered, and injected it into the jugular vein of the animald occurred before.
Hormones
Chemical signaling molecules produced by the endocrine glands and secreted into the bloodstream. Travel in the blood to target cells close by or far away from the point of secretion.
Compare and contrast the endocrine system and the nervous system.
Both use chemical secretion to conduct information.
Mode and specificity of delivery to intended receiver greatly differ.
Nervous system: signal goes straight from sender to reciever along closed lines (axons) - rapid.
Endocrine system: signal generally in the bloodstream, only recievers with the proper reciever can recieve it. Slower.
What major players are there in the endocrine system
Endocrine glands, hormones, binding globulins, target tissues. receptors
Do endocrine glands have ducts
No
