Hypothalamic-Pituitary Relationships and Biofeedback Pt. 1

Question 1

What is the pituitary gland called? What is the anterior pituitary gland called? What is the posterior pituitary gland called?

Answer 1

Pituitary: hypophysis

AP: adenohypophysis (epithelial portion)

PP: neurohypophysis (neural portion)

Question 2

What is the hypophysial stalk?

Answer 2

Physical connection between the hypothalamus and the pituitary gland

Question 3

What is usually associated with pituitary tumors?

Answer 3

Visual problems, dizziness

Question 4

What is found in the posterior pituitary?

Answer 4

Collection of axons and nerve terminals whose cell bodies are located in the hypothalamus, specifically from supraoptic nucleus and paraventricular nucleus

Question 5

What does the posterior pituitary secrete?

Answer 5

ADH from supraoptic nucleus and oxytocin from periventricular nucleus

These are neuropeptides

Question 6

What is found in the anterior pituitary?

Answer 6

Collection of endocrine cells derived from primitive foregut

Question 7

How is the anterior pituitary connected to the hypothalamus?

Answer 7

Connected by hypothalamic-hypophysial portal blood vessels

Question 8

What hormones are secreted by the anterior pituitary?

Answer 8

ACTH, TSH, FSH, LH, GH, prolactin

Question 9

These hormones can be directly delivered to the anterior pituitary in high concentrations, but do not appear in high concentrations in systemic circulation.

Answer 9

Hypothalamic-releasing hormones or release-inhibiting hormones

Question 10

The connections between the hypothalamus and the posterior pituitary are _______. The connections between the hypothalamus and the anterior pituitary are both ______ and _______.

Answer 10

Neural; neural and endocrine

Question 11

What makes up the ACTH family in the anterior pituitary?

Answer 11

Corticotrophs, which secrete ACTH

Question 12

What makes up the TSH, FSH, LH family in the anterior pituitary?

Answer 12

Thyrotrophs, which secrete TSH and gonadotrophs, which secrete FSH and LH

Question 13

What makes up the GH and prolactin family in the anterior pituitary?

Answer 13

Somatotrophs, which secrete GH and lactotrophs, which secrete prolactin

Question 14

What is primary endocrine disorder?

Answer 14

Low or high levels of hormones due to defect in the peripheral endocrine gland

Question 15

What is secondary endocrine disorder?

Answer 15

Low or high levels of hormones due to defect in the pituitary gland

Question 16

What is tertiary endocrine disorder?

Answer 16

Low or high levels of hormones due to defect in the hypothalamus

Question 17

What are the anterior pituitary gland axes?

Answer 17

Hypothalamic-pituitary-gonad
Hypothalamic-pituitary-liver
Hypothalamic-pituitary-prolactin
Hypothalamic-pituitary-thyroid
Hypothalamic-pituitary-adrenal

Question 18

How are FSH and LH regulated?

Answer 18

Regulated by hypothalamic GnRH release (pulsatile); extreme energy deficits (anorexia nervosa or starvation), extreme exercise, and depression can inhibit GnRH function

Question 19

What is the function of FSH and LH?

Answer 19

Promotes estrogen and progesterone secretion in females; promotes testosterone production in males

Question 20

What does a normal menstrual cycle depend on?

Answer 20

LH and FSH

Question 21

What is acromegaly?

Answer 21

Characterized by excessive growth of soft tissue, cartilage, and bone in the face, hands, and feet; develops very gradually and may not be recognized until has been present for many years; caused by prolonged and excessive secretion of GH in adult life

Question 22

What does GH target? What is the GH receptor linked to? How is GH regulated?

Answer 22

Targets liver and bone; GH receptor linked to JAK-STAT signaling; inhibited by somatostatin and IGF-1 signaling as part of negative feedback

Question 23

What stimulates GH?

Answer 23

Fasting/hunger/starvation, hypoglycemia, hormones of puberty, exercise, sleep, stress

Question 24

What are the direct actions of GH?

Answer 24

Growth, cell reproduction, metabolism (increase glyogen and fat breakdown for energy and increased protein synthesis)

Question 25

What is hypertrophy? Give an example

Answer 25

Increase in size/volume of cells; example is increased bone thickness

Question 26

What is hyperplasia? Give an example

Answer 26

Increase number of cells or proliferation rate via mitosis; example is increase in bone length

Question 27

What are the indirect actions of GH?

Answer 27

Majority of growth is indirect method; tropic function; signals to liver to produce IGF (insulin-like growth factors); targets almost every cell in the body; stimulates hypertrophy and hyperplasia

Question 28

What are the somatostatins? Where are they located?

Answer 28

Growth hormone release hormone (GHRH) and growth hormone inhibiting hormone (GHIH); hypothalamus

Question 29

What are the somatotropins? Where are they located?

Answer 29

Growth hormone (GH); anterior pituitary

Question 30

What are the somatomedin C's? Where are they located?

Answer 30

Insulin-like growth factor (IGF) and insulin-like growth factor 1 (IGF-1); liver

Question 31

What is gigantism?

Answer 31

Excess in GH before closure of bone epiphyses due to IGF-1 stimulated long bone growth; before puberty

Question 32

What is acromegaly?

Answer 32

Excess in GH after closure of bone epiphyses due to promotion of growth of deep organs and cartilaginous tissue; after puberty

Question 33

Describe prolactin (PRL)

Answer 33

Synthesized by lactotropes; secretion begins to increase around 5th week of pregnancy; secretion is pulsatile; it is under tonic inhibition by hypothalamic dopamine; primary action is to stimulate and maintain lactation; suppresses GnRH (inhibits FSH/LH); decreases reproductive function and suppresses sexual drive

Question 34

What are stimulating factors for PRL secretion?

Answer 34

Pregnancy (estrogen), breast-feeding (suckling), sleep, stress, TRH

Question 35

What are inhibitory factors for PRL secretion?

Answer 35

Dopamine, dopamine agonists, somatostatins, prolactin via negative feedback

Question 36

Describe pituitary adenomas

Answer 36

Hormone-producing pituitary adenomas that release an active hormone in excessive amounts into the bloodstream; patients usually experience symptoms related to the hormone action on the body

Question 37

What are some examples of pituitary adenomas and what is their percentage of occurrence?

Answer 37

Prolactinoma (60%), acromegaly/gigantism (20%), and Cushing's disease (10%)

Question 38

What are causes of hypopituitarism?

Answer 38

1) Brain damage - traumatic brain injury, subarachnoid hemorrhage, irradiation, stroke 2) Pituitary tumors 3) Non-pituitary tumors - craniopharyngioma (most common tumor affecting the HP axis in children) 4) Infections - meningitis, encephalitis, hypophysitis 5) Infarction - sheehan syndrome (pituitary in pregnancy is enlarged and more vulnerable to infarction) 6) Autoimmune disorders 7) Pituitary hypoplasia or aplasia 8) Genetic disorders

Question 39

What are the actions of oxytocin?

Answer 39

Milk ejection and uterine contractions

Question 40

What does milk letdown cause?

Answer 40

Stimulates contraction of myoepithelial cells lining milk ducts

Question 41

What is pitocin?

Answer 41

Induction of labor