E

Endocrine System, chapter 3.

Overview of the Endocrine System

  • Discussing various glands: thyroid, pituitary, pericardial diverge gland, pancreas, adrenal glands.

  • Emphasis on collaboration in lab studies focusing on case studies.

  • Labs designed to be engaging and promote student participation.

Lab Structure

  • Focus on patients 1 and 2 in lab this week.

  • Introduction of a game "win your freedom" instead of traditional quizzes—correct answers allow early exit.

  • Encourage reviewing case studies ahead of class to facilitate easier discussions.

Upcoming Deadlines

  • Sunday night deadlines:

    • Additional endocrine quiz focused on hormone interactions and chemistry.

    • Endocrine case studies (Exercise 3) due.

  • Preparation for the first test next Thursday; review of study guide suggested.

Pituitary Gland

  • Known as the "master gland" of the endocrine system.

  • Anatomical location near hypothalamus, inside the sella turcica of the sphenoid bone.

  • Comprises two sections: anterior pituitary (also known as adenohypophysis) and posterior pituitary (neurohypophysis) with distinct functions.

Anterior Pituitary

  • Produces 6 hormones, mnemonic: GTAFLP.

  • Functions controlled by hypothalamic stimuli via a specialized blood vessel network (hypophyseal portal system).

  • All anterior pituitary hormones are protein-based and interact using second messenger systems.

Posterior Pituitary

  • Contains nervous tissue, does not produce its own hormones; stores hormones from hypothalamus: oxytocin and ADH.

  • Relies on hypothalamus for signals and hormone release.

Hormonal Functions

Growth Hormone (GH)

  • Stimulus: hypothalamus; major influencers include exercise and low blood sugar.

  • Target areas: bones (growth at epiphyseal plates), liver (energy release), adipose tissue (fat breakdown).

  • Hyposecretion leads to pituitary dwarfism; hypersecretion causes gigantism in children and acromegaly in adults.

Thyroid Stimulating Hormone (TSH)

  • Stimulus: hypothalamus releases thyrotropin-releasing hormone (TRH).

  • Target: thyroid gland, effects include stimulating gland to release thyroid hormones (T4 and T3).

  • Inhibition occurs via negative feedback from high hormone levels.

Adenocorticotropic Hormone (ACTH)

  • Stimulus: hypothalamus; influenced by stress and fever.

  • Target: adrenal cortex, promoting glucocorticoid release.

  • Negative feedback regulation.

Follicle Stimulating Hormone (FSH)

  • Stimulus from hypothalamus; inhibitors include sex hormone levels.

  • Target: gonads (ovaries/testes), effects include maturation of eggs and sperm.

  • Critical for normal sexual maturation and reproductive health.

Luteinizing Hormone (LH)

  • Similar dynamics as FSH; triggers ovulation and sex hormone release from gonads.

  • Key role in reproductive processes, especially in female ovulation.

Prolactin

  • Stimulus: primarily tactile stimulation of breasts post-birth.

  • Target area: breast tissue; significant role in milk production and ejection.

  • Hyposecretion leads to decreased milk production; hypersecretion can result in excessive milk production.

Oxytocin

  • Stimulated by uterine stretch and tactile stimulation; associated with social bonding/prosocial behavior.

  • Functions to contract uterine muscles during childbirth and stimulate milk ejection.

  • Operates primarily under positive feedback mechanisms.

Antidiuretic Hormone (ADH)

  • Stimulus includes pain and low blood pressure; acts on kidneys to conserve water.

  • Low ADH results in diabetes insipidus with symptoms of polyuria and thirst; high levels lead to concentrated urine.

  • Importance of monitoring urine output for diagnosing potential ADH deficiencies.