Download 8.2 Major Endocrine Organs

Chapter 8: The Endocrine System
Lesson 8.2
Major Endocrine Organs
Major Endocrine Organs
1. Hypothalamus
2. Pituitary Gland
3. Thyroid Gland
4. Parathyroid Gland
5. Thymus Gland
6. Pineal Gland
7 Adrenal Glands
8. Pancreas
9. Gonads
Figure 8.1 - page 269
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The Hypothalamus
The Endocrine System is run by the Hypothalamus
- Buried deep within the brain (4 grams)
- Collects information from each body system
+ integrate response with the NS
+ maintains homeostasis by regulating
» metabolism
» heart rate
» energy level
» body temperature
» Thirst
The Hypothalamus controls by releasing hormones to stimulate/inhibit Pituitary Hormones.
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Pituitary Gland
Pituitary Gland
- pea shaped, two lobes
- located in the depression
of the Sphenoid bone
- suspended underneath
the Hypothalamus by a
short stalk.
infundibulum
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Hormones of the Anterior Pituitary
Figure 8.6 – page 277
Anterior Pituitary
secretes two types of
hormones:
- act directly on
targeted tissue
- stimulate other
endocrine glands
Tropins
- lastly, stores
hormones of the
hypothalamus
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Hormones of the Anterior Pituitary
• growth hormone (GH) - directly affect
– growth of bone and muscles
• prolactin (PRO) – directly affect
– growth of mammary glands
– milk production in a nursing mother
• adrenocorticotropin hormone (ACTH) - Tropin
– release of steroid hormones from adrenal cortex
• thyroid-stimulating hormone (TSH) - Tropin
– release of T4 and T3 from thyroid gland
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Hormones of the Anterior Pituitary
• follicle-stimulating hormone (FSH) - Tropin
– in females
• estrogen production
• egg production
– in males
• sperm production
• luteinizing hormone (LH) - Tropin
– in females
• ovulation
– in males
• testosterone
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Hormones of the Posterior Pituitary
Produced in the Hypothalamus,
stored in the posterior Pituitary
• antidiuretic hormone
– acts on kidney, decreases
urine output
Figure 8.7 – page 278
• oxytocin
– acts on uterus, causes
contractions
– acts on breast, causes
secretion of milk
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Major Endocrine Glands - Thyroid
• Thyroid gland
- inferior to the larynx, two inches long, butterfly
shaped, lies front and sides of the trachea
– Secrete two hormones
• Thyroid hormone (needs iodine)
- thyroxine T4 and triiodothyronine T3
- controls rate of metabolism
• Calcitonin
- removes calcium from blood, puts into
bones
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Major Endocrine Glands - Parathyroid
• Parathyroid gland
– parathyroid hormone (PTH) – increases blood calcium
levels
Three ways:
1. removes calcium from bones (breakdown osteoclasts),
puts into blood
2. Increase calcium absorption in intestines
3. Stimulate kidney reabsorption of calcium from urine
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Major Endocrine Glands – Thymus &
Pineal
• Thymus gland
–
–
–
–
Both part of endocrine and lymphatic system
Lies under sternum and anterior to heart
Large during childhood, shrinks with age
Thymosin
• development of immune system – T lymphocytes (white
blood cells) aka T Cells
• Pineal gland
– Pine cone shaped in brain – unclear how it works
– Melatonin
• produces sleepiness
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Thyroid and Parathyroid Glands
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Adrenal Glands
• adrenal medulla
– epinephrine and norepinephrine
• adrenaline rush
• adrenal cortex
– mineralocorticoids
• aldosterone
• sodium and water reabsorbed in kidneys
– glucocorticoids
• cortisone and cortisol
• promote gluconeogenesis
– sex hormones
• estrogen and androgens
• maintains sexual characteristics
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Adrenal Glands
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Pancreas
• islets of Langerhans
– alpha cells
• glucagon
• increase blood glucose level
– beta cells
• insulin
• decrease blood glucose level
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Gonads
• testes
– testosterone
• sperm production
• ovaries
– estrogen
• secondary sexual characteristics
• progesterone
• menstrual cycle
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Review and Assessment
Fill in the blanks with: ADH, thyroxine, thymosin, or
adrenal cortex.
1. The thymus gland produces _______________.
2. The posterior pituitary gland produces oxytocin
and _______________.
3. Mineralocorticoids are produced by the
_______________.
4. T4 is also called _______________.
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