Lecture 6: Hormones Flashcards
What are Hormones?
They enable communication between cells
What do Hormones do?
They are carried in the blood stream to specific target regions (other endocrine glands, organs, cells, the brain)
What are Exocrine Glands?
They secrete products to outside of the body through ducts (Sweat, tears)
What do Hormones regulate?
Growth and Development
Reproduction
Metabolism
Maintenance of internal environment - temp, sleep
Control of internal organs and systems - hr, bp
How is Hormone release regulated?
Through the process of Negative Feedback. Output from a gland (hormone) responsible for preventing further release.
What does the Pineal Gland Release?
Melatonin
What is Entrainment?
Matching of a physiological event to an environmental oscillation.
What are the steps of Melatonin production?
Pineal Gloand produces melatonin in the evening. Melatonin levels peak in middle of night.
Melatonin levels decline to low day time amounts.
Where is the Hypothalamus located?
Base of brain
What is the role of the Hypothalamic Nuclei?
They synthesise Hypothalamic Releasing Hormones which either stimulate or inhibit hormone release from pituitary gland.
What is the Pituitary Gland?
The Master Gland. It releases Tropic Hormones - hormones which influence the release of hormones from other glands.
What is the Anterior Pituitary?
Controlled by Hypothamalic Releasing Hormones
What is the Posterior Pituitary?
Controlled by nerve stimulation from hypothalamus.
(PPG) What is the Anti-diuretic Hormone? (ADH/Vasopressin)
Stimulates re-absorption of water by kidneys (conserves water as prevents it being lost in urine). Stimulates vasoconstriction (high bp in response to stress)
(PPG) What is Oxytocin?
Causes muscle contraction in uterus (handy in childbirth)
Stimulates ejection of breast milk (handy but not always)
(PPG) What is the Oxytocin - Tend or Befriend Hormone?
Elevated levels during sexual arousal and orgasm. Levels respond to social simulations causing anti-stress effects (inhibiting stress hormones)
(APG) What is the Growth Hormone?
Pre-pubertal deficits - Pituitary Dwarfism
Pre-pubertal excess - Gigantism
(APG) What is the Thyroid Stimulating Hormone?
Stimulates the release of Thyroxine by thyroid gland. If thyroid gland is unable to produce enough thyroxine, it swells up in attempt to meet deficit. This is called a Goiter
(APG) What are Gonadotrophins?
Sex hormone release
(APG) What is the Luteinzing Hormone?
It increases production of Progesterone (ovaries) and Testosterone (testes and adrenal cortex)