Glucocorticoids• High levels of circulating cortisol, as seen

with corticosteroid drugs (prednisone), or tumors (adrenal cortex, pituitary gland) is called Cushing’s syndrome– Manifestations include hyper-

glycemia, poor wound healing, osteoporosis, dermatitis, fatredistribution (spindly arms and legs, moon face, buffalo hump at the neck), and truncal obesity

GlucocorticoidsIn adults, hyposecretion of glucocorticoids

and aldosterone, usually as a result of an autoimmune disorder, is called Addison’s disease– The physiologic effects include

hypoglycemia, Na+ loss, low BP, dehydration, and muscle weakness• only after his death did the world

learn that President Kennedysuffered from Addison’s disease

The Adrenal Medulla• The inner region of the adrenal gland, the

adrenal medulla, is a modified sympathetic ganglion that develops from the same embryonic tissue as all other sympathetic ganglia of the ANS and is innervated by sympathetic preganglionic neurons– The catecholamines epinephrine (80%), and

norepinephrine (20%), are secreted at the adrenal medulla and serve to prolong the sympathetic response

ADRENAL MEDULLA HORMONES(Interactions Animation)

• Epinephrine/Norepinephrine

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The Pancreas• The pancreas is both an endocrine and an

exocrine gland. It is located posterior and inferior to the stomach. We will discuss its endocrine functions here and its exocrine functions in detail in chapter 24

• Most of the exocrine cells of the pancreas are arranged in clusters called acini and produce digestive enzymes which flow through ducts into the GI tract– Distributed among the acini are clusters of

endocrine tissue called pancreatic

islets (islets of Langerhans)

The Pancreas

• Each pancreatic islet contains four types of hormone-secreting cells: alpha (A), beta (B), delta (D), and F cells– Alpha cells secrete glucagon which increases

blood glucose levels by acting on hepatocytes to convert glycogento glucose– Beta cells secrete

insulin

Pancreatic Hormones

Pancreatic Hormones• Insulin is an anabolic hormone - it decreases blood

glucose levels by acting on

hepatocytes to convert glucose

to glycogen and then facilitating

diffusion of glucose into the cells

• Insulin and glucagon are counter-

regulatory hormones in that

their actions act to balance one

another in terms of blood glucose

• Somatostatin acts in a paracrine manner to

inhibit both insulin and glucagon release from

neighboring beta and alpha cells. It

also inhibits the secretion of hGH

• The interactions of the

four pancreatic hormones

are complex and not completely understood

Pancreatic Hormones

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

1

GLUCAGON

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

GLUCAGON

1

2 Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

GLUCAGON

1

2

3

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

If blood glucosecontinues to rise,hyperglycemia inhibitsrelease of glucagon

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

GLUCAGON

1

2

3

4

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

If blood glucosecontinues to rise,hyperglycemia inhibitsrelease of glucagon

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

High blood glucose(hyperglycemia)stimulates beta cellsto secrete

GLUCAGON

1 5

2

3

4

INSULIN

Insulin acts on variousbody cells to:

• accelerate facilitated diffusion of glucose into cells• speed conversion of glucose into glycogen (glycogenesis)• increase uptake of amino acids and increase protein synthesis• speed synthesis of fatty acids (lipogenesis)• slow glycogenolysis• slow gluconeogenesis

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

If blood glucosecontinues to rise,hyperglycemia inhibitsrelease of glucagon

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

High blood glucose(hyperglycemia)stimulates beta cellsto secrete

INSULINGLUCAGON

1 5

2

3

4

6 Insulin acts on variousbody cells to:

• accelerate facilitated diffusion of glucose into cells• speed conversion of glucose into glycogen (glycogenesis)• increase uptake of amino acids and increase protein synthesis• speed synthesis of fatty acids (lipogenesis)• slow glycogenolysis• slow gluconeogenesis

Blood glucose level falls

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

If blood glucosecontinues to rise,hyperglycemia inhibitsrelease of glucagon

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

High blood glucose(hyperglycemia)stimulates beta cellsto secrete

INSULINGLUCAGON

1 5

2

3

4

6

7

Insulin acts on variousbody cells to:

• accelerate facilitated diffusion of glucose into cells• speed conversion of glucose into glycogen (glycogenesis)• increase uptake of amino acids and increase protein synthesis• speed synthesis of fatty acids (lipogenesis)• slow glycogenolysis• slow gluconeogenesis

If blood glucose continuesto fall, hypoglycemiainhibits release ofinsulin

Blood glucose level falls

Glucagon acts onhepatocytes(liver cells) to:

• convert glycogen into glucose (glycogenolysis)• form glucose from lactic acid and certain amino acids (gluconeogenesis)

Glucose releasedby hepatocytesraises blood glucoselevel to normal

If blood glucosecontinues to rise,hyperglycemia inhibitsrelease of glucagon

Low blood glucose(hypoglycemia)stimulates alphacells to secrete

High blood glucose(hyperglycemia)stimulates beta cellsto secrete

INSULINGLUCAGON

1 5

2

3

4

6

7

8

Glucose/InsulinRegulation

PANCREATIC HORMONES(Interactions Animation)

• Insulin

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Gonadal Hormones• The ovaries are paired oval bodies located in

the female pelvic cavity. They produce several steroid hormones including two estrogens (estradiol and estrone), progesterone, relaxin, and inhibin – Estrogens, along with FSH and

LH from the anterior pituitary, regulate the menstrual cycle, maintain pregnancy, and prepare the mammary glands for lactation

Gonadal Hormones• Ovarian hormones also promote

enlargement of the breasts and widening of the hips at puberty, and help maintain these female secondary sex characteristics– Progesterone prepares the uterus lining for

implantation of a fertilized ovum

OVARIAN HORMONES(Interactions Animation)

• Hormonal Regulation of Female Reproductive System

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Gonadal Hormones• The male gonads, the testes, are oval glands

that lie in the scrotum. The main hormone produced and secreted by the testes is testosterone, an androgen (male sex hormone)– Testosterone is needed for

production of sperm and maintenance of male secondary sex characteristics

TESTICULAR HORMONES(Interactions Animation)

• Hormonal Regulation of Male Reproductive Function

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