BIO 378
Lecture 6: Endocrine System

The endocrine system is comprised of glands.

Glands are - Group of specialized cells that produce secretions
 

Exocrine glands: Secrete through a duct
 

Endocrine glands: Ductless, secrete hormones directly into blood stream
 
 

Hormones: Regulate activities of cells and other organs
 
 
 

Target tissue: Specific tissue acted upon by a hormone
 
 

Some endocrine glands:

1. Pituitary
2. Thyroid
3. Parathyroid
4. Adrenal
5. Pancreas
6. Gonads

Pituitary gland: Master Gland; it releases hormones that effect the function of other glands; controlled by hypothalamus
 
 
 

    Anterior pituitary: also called adenohypophysis
 

        produces:
            1. (HGH) - Human Growth Hormone, stimulates body growth
            2. (TSH) - Thyroid Stimulating Hormone, stimulates thyroid to produce hormones
            3. (FSH) - Follicle Stimulating Hormone, promotes follicle development in women, physical maturation of sperm in males
            4. (LH) - Lutenizing Hormone, induces ovulation in women & promotes estrogen and progesterone secretions, in males stimulates production of sex hormones
 

    Posterior Pituitary: neurohypophysis, stores and releases:
            1. Oxytocin-released prior to giving birth
 

            2. Antidiuretic Hormone-causes kidney to reabsorb water
 

Thyroid gland:
             1. Thyroxine (T4)

             2. Triiodothyronine (T3)

             3. Thyrocalcitonin

Parathyroid:
  On posterior side of thyroid gland, regulates calcium levels in blood
 

Adrenal glands: on top of each kidney

    Adrenal Cortex:
            1.  mineralcorticoids

            2.  glucocorticoids

            3.  sex hormones

    Adrenal Medulla:
            1. norepinephrine

            2. epinephrine
 

Pancreas:
    Islets of Langerhans
            1.  Alpha Cells produce Glucagon-causes liver to release glucose
 

            2.  Beta Cells produce Insulin-reduces blood glucose levels by causing liver to take glucose from blood stream and store it
 

Gonads:

    Testes:
  Produce testosterone and sperm
 
 
 

    Ovaries:
  Produce hormone estrogen and progesterone, produces eggs
 
 
 
 

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