1QQ#8 10:30

A) Peptide hormones are stored in intracellular vesicles and released as needed.

B) Renin is secreted from the adrenal cortex in response to a drop in blood pressure.

C) Aldosterone acts to boost blood pressure by enhancing the retention of sodium by the kidneys.

D) Oxytocin reaches the posterior pituitary gland by way of the hypothalamo-hypophyseal portal system.

E) Trophic hormones stimulate the growth of their target cells.

Write A B C D E and circle the letter of each correct response.

1QQ#8 11:30

A) Catecholamine hormones are stored in vesicles and released as needed.

B) Renin is secreted from the adrenal medulla in response to a drop in blood pressure.

C) As blood pressure gets higher and higher, renin secretion should decrease.

D) The neurohypophysis is connected to the hypothalamus by the hypothalamo-hypophyseal portal system.

E) A hormone is said to be a tropic hormone if it stimulates the growth of its target cells.

Write A B C D E and circle the letter of each correct response.

Fig. 11.12b

NeurohypophysisAdenohypophysis

6

S4

2

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 1

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 2

Thyroid Gland

• TH =T3 and T4

Fenestrated Capillary(typical of endocrine glands

and digestive tract)

S3

Hematoxylin and Eosin Stain:H stains nucleic acids dark blue.E stains proteins and carbs pink.

Other classes of capillaries:continuous (in CNS) anddiscontinuous (in liver, bone marrow, spleen)

Biopsy of normal Thyroid Gland

Synthesis, Storage and Secretion of T3 and T4Roles of TSH (Thyroid Stimulating Hormone)

TH essential for normal development, increases cell metabolism & heat production (Basal Metabolic Rate)

Tropic: directs controls, regulatesTrophic: growth

S4

=Adrenergic Receptor

Transcription Factor

Fig. 11.08

Thyroid hormone stimulates production of beta-adrenergic receptors, which increases the target cell’s responsiveness to EPI.

Permissive effect

S5

Who Cares?

• Symptoms of hypothyroidism

• Levels of TSH and TH?

• Explain enlarged thyroid gland

• Cause: Inadequate dietary intake of iodine

• Treatment?

EndemicGoiter

TRH

TSH

T3 & T4

Goiter

Elevates basal metabolic rate,potentiates response to EPI

If hypothyroid during pregnancy…cretinism = congenital hypothyroidism

S 7

Synthesis, Storage and Secretion of T3 and T4Roles of TSH (Thyroid Stimulating Hormone)

Tropic: directs controls, regulatesTrophic: growth

S 8

Folliclesswell withthyroglobulin

Who else Cares?

Aunt Dot S 9

Symptoms: nervousness, palpitations, hyperactivity, increased sweating, heat hypersensitivity, fatigue, increased appetite, weight loss, insomnia, weakness, and frequent bowel movements (occasionally diarrhea). Signs may include warm, moist skin; tremor; tachycardia; atrial fibrillation; and palpitations. Source: Merck Manual

Many common symptoms of hyperthyroidism are similar to those of adrenergic excess.

Blood tests for catecholamine levels are normal!

Aunt Dot’s Blood Test Results

• T3 and Total T3 very high

• TSH very low

S 10

T3 and T4 from Thyroid gland

TSH from Ant. Pit.

TRH from Hypothal.

⇧Metabolic rate

⇧Temperature⇧sensitivity to EPI (up-regulation of adrenergic receptors)

⇧Heart rate and ⇧Blood Pressure

⇧Lipolysis and fuel mobilization Weight loss

The cause: Abnormal Immunoglobulins in patient activate TSH receptors on Thyroid cells

⇩

⇩

Grave’s Disease = one form of Thyrotoxicosis

S 11

Blood test:TSH levels lowTH levels high

Treating thyrotoxicosis with Radioactive Iodine

Accumulation of radioactive iodineKills follicular cells.

S 12

S 13

Aunt Dot and Uncle Harold

Quiz #7

Choose two of the following false or misleading statements and make the appropriate corrections:

1)Steroid hormones are stored in secretory vesicles at the time of release from a stimulated endocrine cell.

2)All amine hormones are hydrophillic molecules that easily dissolve in water and bind to receptors in the plasma membrane of the target cell.

3)Thyroid hormone and epinephrine are synergistic because either can stimulate the breakdown of fatty acids in adipocytes but together they enhance the process.

4)All hormones released from the pituitary are produced by cell bodies in the hypothalamus.

Note: next Monday’s quiz will be based on material from this week’s lab.

Age 16, 33, 52S 14

Another Endocrinological Disorder