1QQ # 4: Answer one.1. Starting with a drop in blood pressure, diagram the

sequence of events that begins with the secretion of renin and ends with responses that act to restore blood pressure toward normal.

2. A) What gland is the source of Thyrotropin Releasing Hormone? B) What are the target cells of TRH? C) How does TRH get to its target cells (be specific.) D) What do the target cells of TRH do when stimulated by TRH? E) How is the secretion of TRH affected as the concentration of T4 increases?

Thyroid Gland

• TH =T3 and T4

Fenestrated Capillary(typical of endocrine glands)

S1

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

TH increases cell metabolism & heat production (BMR)

Tropic: directs controls, regulatesTrophic: growth

S2

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 4

Who else Cares?

Aunt Dot S 5

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

S 6

Blood test:TSH levels lowTH levels high

Grave’s Disease

Treatment:Radioactive IodineMechanism:……..

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) can lead to Cushing’s Syndrome!

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