Endocrine System

1,384 views
1,288 views

Published on

Published in: Technology, Health & Medicine
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,384
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
195
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Endocrine System

  1. 2. <ul><li>Greek- to excite </li></ul><ul><li>Chemicals released in minute amount that can elicit specific response </li></ul><ul><ul><li>Not all hormones are released by glands (e.g. Hypothalamus) </li></ul></ul>
  2. 3. <ul><li>Nerves communicate faster due to impulses and structure of neurons </li></ul><ul><li>The endocrine system is responsible for slower biological processes (e.g. Growth) </li></ul>
  3. 4. <ul><li>The endocrine system and nervous system are structurally, chemically and functionally related </li></ul><ul><li>Presence of neurosecretory cells- specialized neurons </li></ul><ul><li>Chemicals that function as both hormones and neurotransmitters </li></ul>
  4. 5. <ul><li>Positive feedback </li></ul><ul><ul><li>Nervous- opening of sodium ion gates during the threshold potential </li></ul></ul><ul><ul><li>Endocrine- release of milk </li></ul></ul><ul><li>Negative feedback </li></ul>
  5. 6. <ul><li>Hydra- hormone for growth and budding; prevents sexual reproduction </li></ul><ul><li>More complex- both are integrated in the control of reproduction and development </li></ul><ul><li>Aplysia- hormone for egg-laying counters feeding and locomotion </li></ul><ul><li>Arthropods - presence of ecdysone </li></ul><ul><ul><li>Insects- secreted by prothoracic glands </li></ul></ul>
  6. 7. <ul><li>Responsible for molting </li></ul><ul><li>Favors metamorphosis </li></ul><ul><li>Some insects- presence of brain hormone (BH) </li></ul><ul><ul><li>Promotes development by stimulating the prothoracic glands </li></ul></ul><ul><li>Juvenile hormone (JH)- balances BH and ecdysone </li></ul><ul><ul><li>From corpora allata </li></ul></ul>
  7. 8. <ul><li>Occurs when corpora allata stops producing JH </li></ul><ul><ul><li>Regulation of production is not known </li></ul></ul><ul><li>Could be nervous or neurohormonal </li></ul><ul><li>Adult: inhibition via nervous connection in the brain </li></ul>
  8. 9. <ul><li>Larvae: corpora allata is activated by neurohumoral factor from the brain during development </li></ul><ul><li>Inactivated by nervous inhibition before metamorphosis </li></ul>
  9. 10. <ul><li>Endocrine glands- ductless glands that release hormones (via the bloodstream) </li></ul><ul><li>Paracrine glands- like endocrine but target adjacent cells </li></ul><ul><li>Exocrine glands- release secretions through ducts </li></ul>
  10. 11. <ul><li>Holocrine- releases secretions through rupture of the plasma membrane (oil gland) </li></ul><ul><li>Apocrine – releases secretions through membrane-bound vesicles (mammary gland) </li></ul><ul><li>Merocrine- releases their secretion through exocytosis of their secretory vesicles </li></ul>
  11. 13. <ul><li>hormones- via the bloodstream </li></ul><ul><li>Local regulators- targets nearby cells </li></ul><ul><li>Pheromones- carry messages to different individuals </li></ul><ul><ul><li>Mate attraction </li></ul></ul>
  12. 14. <ul><li>Secreted by cells to nearby/adjacent target cells </li></ul><ul><ul><li>E.g. Interleukin, growth factor </li></ul></ul>
  13. 15. <ul><li>Peptides and proteins that stimulate cell proliferation </li></ul><ul><li>a given growth factor can have different effects depending on the target cell </li></ul><ul><ul><li>Nerve growth factor (NGF) </li></ul></ul><ul><ul><ul><li>Speeds up development of embryonic nerve cells </li></ul></ul></ul><ul><ul><ul><li>Also affects developing white blood cell and other kinds of cell </li></ul></ul></ul>
  14. 16. <ul><li>A form of a non-surgical operation in treating injuries </li></ul><ul><li>Use of blood plasma where some growth factors are present </li></ul>
  15. 17. <ul><li>Highly reactive and toxic </li></ul><ul><li>Action is rapid </li></ul><ul><li>When secreted by neurons: neurotransmitter </li></ul><ul><li>WBC: kills bacteria and cancer cells </li></ul><ul><li>Endothelial cells: dilate BVs; relax smooth muscles </li></ul>
  16. 18. <ul><li>Modified fatty acid from lipids of plasma membrane </li></ul><ul><li>First found in semen </li></ul><ul><li>In semen: stimulates uterine contraction </li></ul><ul><li>In placenta: induce labor </li></ul><ul><li>Induce fever, inflammation and intensify sensation of pain </li></ul><ul><li>PGE: muscle relaxation in the lungs </li></ul><ul><li>PGF: muscle contraction in the lungs </li></ul>
  17. 19. <ul><li>Signal molecule: has specific shape </li></ul><ul><li>Reception: binding of signal to receptor </li></ul><ul><ul><li>Located at the plasma membrane or inside the cell </li></ul></ul><ul><li>Signal transduction- series of events signalled by the reception of signal mol on the plasma membrane </li></ul><ul><li>Response- change in a cell’s behavior </li></ul>
  18. 20. <ul><li>Occurs if there is a correct signal molecule </li></ul><ul><li>Specific receptor is present </li></ul><ul><li>Depends on the location of the binding site of a signal molecule </li></ul>
  19. 21. <ul><li>Signal transduction </li></ul><ul><ul><li>Receptor is on the surface </li></ul></ul><ul><ul><li>Composed of series of events that can lead to a response </li></ul></ul><ul><ul><li>E.g. Response is in the form of enzyme activation </li></ul></ul><ul><li>Change in gene expression </li></ul><ul><ul><li>Signal molecule penetrates the cell and binds to a receptor inside </li></ul></ul><ul><ul><li>Receptor acts as transcription factor </li></ul></ul><ul><ul><li>Change in gene expression </li></ul></ul>
  20. 22. <ul><li>Darkness of skin depends on arrangement of melanocytes in the skin </li></ul><ul><li>Light skin: melanosome at the nuclei </li></ul><ul><li>Dark skin: melanosome in the cytoplasm </li></ul><ul><li>Arrangement of melanosome is controlled by MSH </li></ul>
  21. 23. <ul><li>Secreted by the pituitary gland </li></ul><ul><li>MSH present: melanosomes disperse </li></ul><ul><li>MSH absent: at the nuclei </li></ul><ul><li>Direct injection does not lead to dispersion </li></ul><ul><ul><li>Why? </li></ul></ul>
  22. 24. <ul><li>Signal receptor at the plasma membrane </li></ul><ul><li>Converts extracellular signal to intracellular response </li></ul><ul><li>Can amplify a signal to substantial response </li></ul>

×