Produced by endocrine glands Male endocrine glands = Testes Female endocrine glands = Ovaries.
Endocrine System. What is a gland? Gland is a organ that produces secretion Endocrine glands secrete...
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Transcript of Endocrine System. What is a gland? Gland is a organ that produces secretion Endocrine glands secrete...
Endocrine System
What is a gland? Gland is a organ that produces secretion Endocrine glands secrete into blood stream Endocrine glands secrete into a lumen/duct
Functions of Endocrine System Secrete hormones that coordinate and
direct activities of target cells/organs Regulates mood, growth, development,
metabolism, sexual function, reproduction, blood pressure, heart rate
Most systems are under combined control of endocrine and nervous systems
Negative Feedback Loops Endocrine system operates under negative
feedback mechanisms
- think about your home’s thermostat and furnace
Requirements for feedback Hormone – chemical released from
endocrine gland that exerts effect elsewhere
Target- cell that responds to hormone
- must have receptor for hormone
- number of receptors on target cells are in state of flux
Hormones Three categories of hormones1. Proteins:-freely circulate in blood-available for use quickly, short lasting effects2. Amines3. Steroids: -Require special transport proteins-unavailable when bound-allows for a gradual, longer term response
Nervous System Control: Adrenal Medula can be stimulated to
release hormones by sympathetic nervous system
Example: releases epinephrine (adrenalin
Pituitary Gland Know as the master gland Major influencer of body activities Stimulated to release hormones by the
hypothalamus
Thyroid Gland Butterfly shaped gland; sits inferior to
cricoid cartilage Very vascular and rich in blood supply Secretes three hormones
-Triliodothyronine (T3)
-Thyroxine (T4)
-Calcitonin
Parathyroid: Four glands found on posterior thyroid
gland Secretes hormone parathyroid Involved in calcium metabolism
Thymus Gland Endocrine and lymphatic organ Secretes hormone thymosin Stimulates production of lymphocytes
Adrenal Glands Located on top of the kidneys Contains two regions:
1. Medulla
- Norepinephrine – greatest effect is to cause vasoconstiction of blood vessels
-increases blood pressure
Adrenal Glands2. cortex 1. (release of corticoids – steriod hormones) 2. glucocorticoids – mediates inflammation
process and reduces pain 3. androgens – male sex hormones; secreted
in both men and women-post menopause women may develop some male
characteristics-levels are masked by gonads
Gonads Sex glands Females produce estrogen and
progesterone Testosterone causes development of male
reproductive organs
Pancreas Endocrine and exocrine gland located
behind the stomach Exocrine – secrete digestive enzymes into
duodenum Endocrine – regulate glucose metabolism
-regulates own function through paracrine signaling
Islets of Langerhans Contain endocrine cells of pancreas Alpha (A)- cells secrete glucagon Beta (B) cell secrete insulin
Pineal Gland Releases melatonin; causes sleepiness Assists with temperature regulation Involved in mood regulation
- possibly linked to depression
Stimulated by level of light input