Hormones of the adenohypophysis

Question 0

GH stimulates:

Answer 0

• the uptake of amino acids & their conversion into proteins
• the breakdown of fats & the synthesis of glucose
• the production of somatomedins (with GH they promote bone & cartilage growth)

Question 1

1. Growth Hormone (GH)

Answer 1

stimulates growth in most tissues

regulator of metabolism

Question 2

GH secretion increases in response to:

Answer 2

low blood glucose
stress
an increase in certain amino acids

Question 3

GH is regulated by 2 hypothalamic hormones:

Answer 3

Growth hormone-releasing hormone (GHRH)

Growth hormone-inhibiting hormone (GHIH)

Question 4

Hypersecretion of HGH

Hyperglycemia:

Answer 4

high blood sugar levels stimulate pancreas to continuously release insulin

-if it lasts for weeks or months may cause “beta-cell burnout”; little or no insulin is produced –> diabetes mellitis

diabetes mellitis- type 1; insulin dependent; 5-10% of population (young)

Question 5

Hypersecretion of HGH

in children- Giantism:

Answer 5

very tall but body proportions are about normal

-excessive cartilage, bone formation at plates of long bones = longer bones

Question 6

Hypersecretion of HGH

in adults- Acromegaly:

Answer 6

“large extremity”
bones of hands, feet, cheeks, & jaw thicken (no increase in length)
eyelids, lips, tongue, & nose enlarge

-stimulates growth of connective tissues

Question 7

Hyposecretion of HGH

during growth years (12-25)

Answer 7

• slow bone growth so epiphyseal plates close before normal height is reached = pituitary dwarfism
• possible to treat with hormones during childhood

Question 8

Hyposecretion of HGH

Achondroplasia dwarfism

Answer 8

most common type;
produces person with nearly normal sized trunk & head but shorter than normal limbs
(genetic/random)

Question 9

2. Prolactin

Answer 9

-with other hormones it initiates & maintains milk secretion

-milk production is controlled by estrogen & progesterone:
high levels inhibit prolactin effects on mammary glands (after birth, estrogen & progesterone levels decrease & prolactin effects are present)

-prolactin levels rise during pregnancy to prepare body for nursing infant as birth approaches

Question 10

Hypersecretion of Prolactin

Answer 10

males- impotence & infertility

females- absence of menstural cycle, infertility, & inappropriate lactation

Question 11

3. Thyroid Stimulating Hormone (TSH)

Answer 11

TSH stimulates synthesis & secretion of 2 hormones T3 & T4 by the thyroid gland

Question 12

Hypothyroidism

causes

Answer 12

causes: inadequate TSH stimulation of thyroid gland, inability of thyroid to produce thyroid hormones (due to damage to pituitary gland, tumors, blood loss during childbirth)or surgical removal/destruction of thyroid gland

lack of iodine in the diet can result in decreased thyroid hormone levels because iodine is necessary for the synthesis of thyroid hormones