Wednesday, 21 SeptemberChapter 11 The Endocrine System

Chapter 6 Nervous System A and BTwo 1QQs returned on Piano

Lab this week: Analyzing a research paper + First Endocrine Case study.Lab next week: Four more cases in endocrinology

1QQ # for 8:30

1) Suppose the portal vessel that connects the median eminence to the adenohypophysis was completely occluded (blocked.)  Which hypothalamic hormone(s) could not reach their target cells?

a) ACTH   b) CRH   c) DA    d) Prolactin      e) TRH   f) TSH g) FHS     h)  T3      i) GnRH     j) ADH

OR

2A Name the hormone normally secreted by hepatocytes.

2B Name the hormone secreted by cells in the adenohypophysis that stimulates the secretion of the “liver” hormone.

2C Suppose liver cells form a tumor that secretes the “liver” hormone in an unregulated manner. Assuming cells in the adenohypophysis are behaving normally, would the levels of the tropic hormone from the anterior pituitary be normal, high, or low?

Write the number of the one question you choose to answer.

1QQ # for 9:30

1) Suppose the portal vessel that connects the median eminence to the adenohypophysis was completely occluded (blocked.)  Which hypothalamic hormone(s) could not reach their target cells?

a) Oxytocin   b) Prolactin   c) DA    d) CRH      e) TRH   f) TSH g) FHS     h)  T3    i) GnRH     j) ADH

OR

2 Cells in the anterior pituitary gland that secrete TSH

a) have receptors for TRH in their cell membranesb) can sense the levels of T3 and T4 in the plasmac) will release more TSH as levels of TRH rise

d) Should release less TSH after a person has been treated with radioactive iodine

e) Should release less TSH if a person is dosed with exogenous TH.

Write the number of the one question you choose to answer.

Tropic hormones control the function

Trophic hormones promote survival and growth of targets

Releasing Hormone

Release-inhibiting Hormone

Hypothalamo-hypophyseal portal system

A

A

S S

P

P

PPPPP

PPPP

S 6

Tropic hormones control the function

Trophic hormones promote survival and growth of targetsReleasing Hormone Release Inhibiting Hormone

Long

-loop

neg

ativ

e fe

edba

ck

Sho

rt-lo

op N

eg. F

eed.

S 7

⇧Cortisol secretion from Adrenal Cortex

Mobilize fuel from muscle & adipose tissueSuppress non-essential functions (reproduction & growth)Suppress inflammatory &immune responsesPotentiates response to EPI (vascular smooth muscle)

ACTH from Ant. Pit

CRH from Hypothalamus

Physical traumaProlonged exposure to coldProlonged intense exerciseInfectionSleep deprivationPainFrightEmotional distress

Vasopressin

Cytokines fromimmune cells

Excess Cortisol from 1) adrenal cortex tumor (primary) or 2) hypersecretion of ACTH from anterior pituitary (secondary)

Cushing’s Syndrome

Basal levels of CortisolRequired for normal sensitivity to EPI; symptoms of excess cortisol are…..

Clinical example: treatment of chronic inflammation (e.g. arthritis) with high doses of cortisol can lead to Cushing’s Syndrome!

S 8

Who Cares?

⇧Cortisol secretion from Adrenal Cortex

Mobilize fuel from muscle & adipose tissueSuppress non-essential functions (reproduction & growth)Suppress inflammatory &immune responsesPotentiates response to EPI (vascular smooth muscle)

ACTH from Ant. Pit

CRH from Hypothalamus

Physical traumaProlonged exposure to coldProlonged intense exerciseInfectionSleep deprivationPainFrightEmotional distress

Vasopressin

Cytokines fromimmune cells

S 8

Age 16, 33, 52

No Relation!

S 4

Disorder =AcromegalyType of endocrine disorder = ????

• Excessive growth of bones and soft tissues of face and hands, and feet.

• Hypersecretion of Growth Hormone from adenohypophysis or ectopic tumor in adults

• Treatment?

• Somatostatin analogs?

• GH receptor blockers

• Transphenoidal resection/ablation with focal radiation

Compare to Pituitary Gigantism

S 5

GHRH SS

GH

Applied Physiology: MenopauseWidmaier text p. 626-7

• Onset ~ age 50• Irregular menstrual cycles• Breasts and genital organs gradually atrophy• Decrease in bone mass & strength

(osteoporosis) (bone resorption > bone deposition)

• Hot flashes…sweating, etiology unknown• Increased incidence of coronary artery disease

S 9

Menopause, continued.

• Caused by ovarian failure….loss of estrogen• Estrogen has protective function for

cardiovascular system and sustains bone• Diagnosis

– Test estrogen levels– Test FSH levels….interpretation if high?

• Treatment– Hormone replacement therapy– Risk of HRT: increased incidence of breast cancer

& uterine endometrial cancer– Advantages: alleviates symptoms, restores

cardiovascular protection, sustains bone density

S 10

Neurons? Endocrine cells? Neuroendocrine cells?

S 6

Neurons and endocrine cells are very involved in homeostasis. To Chapter 6!