1. The Endocrine System
10/20/2014
Slowly but surely

2. Introduction
The endocrine system includes the organs of the body that secrete hormones directly into body fluids such as blood
Regulates chemical reaction in cells and therefore control functions of the organs, tissues, and other cells
bloodstream to
hormones
Glands
into
secrete
target tissues

3. Hormones Endocrine glands
Ductless
Release hormones
Directly into target tissues
Into bloodstream to be carried to target tissues
Hormones – chemicals secreted by a cell that affect the functions of other cells

4. Hormones (cont.)
Many are derived from steroids that easily cross the cell membrane
Examples of steroid hormones
Estrogen
Progesterone
Testosterone
Cortisol
hormones

5. Hormones (cont.)
Nonsteroidal hormones
Made of amino acids or proteins and cannot cross the cell membrane easily
Bind to receptors on the surface of the cells
G-protein – activated by the hormone-receptor complex
Activates enzymes inside cell
Prostaglandins
Local, or tissue, hormones
Derived from lipid molecules
Do not travel in the bloodstream
Target tissues are located close by
Produced by organs such as
Kidneys
Heart
Stomach
Uterus
Brain

6. Negative and Positive Feedback Loops
Control hormone levels
Negative feedback loop
Hormone release stops in response to decrease in stimulus
Stimulus (eating) raises blood glucose levels
Pancreas releases insulin in response to elevated blood glucose
Blood glucose decreases as it is used by the body or stored in the liver
Insulin release stops as blood glucose levels normalize

7. Negative and Positive Feedback Loops (cont.)
As long as stimulus is present, action of hormone continues
Infant nursing  stimulates hypothalamus  stimulates posterior pituitary
Oxytocin released  stimulates milk production and ejection from mammary glands
Milk release continues as long as infant continues to nurse

8. Apply Your Knowledge VERY GOOD! Match the following:
___ Chemicals that effect cell function A. Nonsteroidal hormone
___ Easily cross cell membranes B. Steroidal hormone
___ Made of amino acids C. G-protein
___ Target nearby cells D. Prostaglandins
___ Activated by hormone-receptor E. Hormones complex
___ Cannot cross cell membranes easily
___ Estrogen and cortisol E
ANSWER: B A D C
VERY GOOD! A B

10. Hypothalamus Hormones
Oxytocin
Antidiuretic hormone (ADH)
Hormones transported to the posterior pituitary for storage
Directs posterior pituitary to release hormones
Glands

11. Pituitary Gland Controlled by the hypothalamus
Located at the base of the brain
Protected by a bony structure called the sella turcica
The optic chiasm is located just above the pituitary gland
Carries visual information to the brain for interpretation
Two lobes
Anterior lobe
Posterior lobe
Glands

12. Pituitary Gland (cont.)
Growth hormone
Prolactin
Stimulates milk production
Stimulates increase in size of muscles and bones
Anterior
Lobe
Thyroid-stimulating
Luteinizing
Stimulates the thyroid gland to release its hormones
Females: stimulates ovulation and estrogen production
Males: stimulates testosterone production
Follicle-stimulating
Adrenocorticotropic
Females: stimulates estrogen production and maturation of the ova
Males: stimulates sperm production
Stimulates the adrenal cortex to release its hormones

13. Pituitary Gland (cont.)
Oxytocin
Posterior
Lobe
Females: causes contraction of the uterus and ejection of breast milk
Males: stimulates contraction of the prostate and vas deferens during sexual arousal
Antidiuretic hormone (ADH)
Stimulates the kidneys to conserve water

14. Super! Apply Your Knowledge ANSWER: Match the following:
D, E
ANSWER:
Match the following:
___ Stored in posterior pituitary A. Follicle-stimulating hormone
___ Milk production B. Prolactin
___ Produced by hypothalmus C. Luteinizing hormone
___ Stimulates sperm production D. ADH
___ Maturation of ova E. Oxytocin
___ Stimulates ovulation
___ Conservation of water
___ Production of testosterone
___ Contraction of uterus B
D, E A A C
Super! D C E

15. Thyroid Gland and Parathyroid Glands
Located below the larynx
Divided into follicles that store some of the hormones
Major hormones
Calcitonin
Thyroid hormones
T T4
Stimulate protein synthesis and increase cellular energy production
Lowers blood calcium levels by activating osteoblasts that build new bone tissue
Glands

16. Thyroid Gland and Parathyroid Glands (cont.)
Four located on the posterior surface of the thyroid gland
Secrete parathyroid hormone (PTH)
Agonist to calcitonin by raising blood calcium levels through activation of osetoclasts (dissolve bone)
As bone dissolves, calcium levels in blood increase
Glands

17. Adrenal Glands Located on top of each kidney
Divided into the adrenal medulla and adrenal cortex
Adrenal medulla
Central portion
Hormones
Epinephrine
Norepinephrine
Same effects as sympathetic nervous system
Glands

18. Adrenal Glands (cont.) Adrenal cortex Outermost portion
Secretes many hormones, but main ones are
Aldosterone
Stimulates body to retain sodium and water
Important in maintaining BP
Cortisol
Released when stressed
Decreases protein synthesis, resulting in slowed tissue repair
Decreases inflammation

19. Pancreas Located behind the stomach
Both exocrine gland and endocrine gland
Exocrine – secretes digestive enzymes into a duct leading to the small intestine
Endocrine – secretes hormones into bloodstream
Glands

20. Pancreas (cont.) Insulin Glucagon
Islets of Langerhans secrete hormones into bloodstream
Alpha cells secrete glucagon
Beta cells secrete insulin
Insulin
Glucagon
Blood glucose concentrations
Blood glucose concentrations
Protein synthesis
Protein synthesis

21. Other Hormone-Producing Organs
Pineal body
Small gland
Located between cerebral hemispheres
Melatonin
Regulates circadian rhythms
May play a role in onset of puberty
Thymus gland
Located between lungs
Thymosin
Promotes production of T lymphocytes
Glands

22. Other Hormone-Producing Organs (cont.)
The gonads
Ovaries
Estrogen
Progesterone
Testes
Testosterone
Stomach
Gastrin
Small intestine
Secretin
Cholecystokinin
Heart
Atrial natriuretic peptide – regulates BP
Kidneys
Erythropoietin – stimulates blood cell production
Glands

23. Common Diseases and Disorders
Disease/Disorder
Description
Acromegaly
Too much growth hormone produced in adults; enlargement of bones and thickened skin
Addison’s disease
Adrenal gland fails to produce enough corticosteroids
Cretinism
Extreme form of hypothyroidism present prior to or soon after birth
Cushing’s disease
Hypercortisolism; over-production of cortisol
Diabetes insipidus
Kidneys fail to reabsorb water, resulting in excessive urination; hyposecretion of ADH

24. Common Diseases and Disorders (cont.)
Disease/Disorder
Description
Diabetes mellitus
Type I
Type II
Gestational
Chronic disease characterized by elevated blood glucose levels
Insulin-dependent diabetes mellitus; usually develops in childhood
Noninsulin-dependent diabetes mellitus; primarily in adults but increased incidence in teens
Occurs during pregnancy; usually temporary
Dwarfism
Too little growth hormone (somatotropin) produced during childhood

25. Common Diseases and Disorders (cont.)
Disease/Disorder
Description
Gigantism
Too much growth hormone produced during childhood
Goiter
Enlargement of thyroid gland, causing swelling in neck; deficiency of iodine in diet
Grave’s disease
Hyperthyroidism; antibodies attach to thyroid gland, causing it to produce too much thyroid hormone
Myxedema
Thyroid gland produces inadequate amounts of thyroid hormone; common in females over 50

26. In Summary
The organs of the endocrine system secrete hormones directly into blood and other body fluids.
Hormones secreted by the endocrine system control the functions of other cells.
Endocrine organs
Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid glands
Adrenal glands
Pancreas
Pineal body
Thymus gland
Gonads, stomach small intestine, heart, kidneys