ENDOCRINE SYSTEM

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ENDOCRINE SYSTEM
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Mechanisms of Chemical Signaling a Review
Water-Soluble/Nonsteroid Hormones
Lipid-Soluble/Steroid Hormones
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Control Pathways and Feedback Loops

• There are three types of hormonal control
  pathways

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One Chemical Signal, Different Effects
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ENDOCRINE GLANDS

• Are ductless and secrete hormones directly into
  the bloodstream
• Target Cells the cells that a hormone directly
  affects
• if a cell does not have receptors or the
  receptors dont respond, the hormone has no
  effect.

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Human Endo-crine Glands
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• Most hormones operate by a negative feedback
  system or feedback inhibition a
• stimulus produces a response that opposes the
  original stimulus an environmental change feeds
  back to inhibit the original stimulus.

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The Reproductive Cycle of the Human Female
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THYROID GLAND

• Located in the neck, is the target gland of
  thyroid-stimulating hormone (TSH)
• When the thyroid is stimulated by TSH it releases
  the hormones Triiodothyronine (T3) and Thyroxine
  (T4), which regulates the metabolic rate of your
  body tissues

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Feedback control loops regulating the secretion
of thyroid hormones T3 and T4
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PARATHYROID GLANDS

• These are four pea-shaped organs that rest on the
  thyroid. They secrete parathyroid hormone which
  increases blood calcium levels the opposite
  effect of what calcitonin does

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An example of how feedback regulation maintains
homeostasis
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THE PITUITARY GLAND

• Often called the master gland because it
  secretes so many hormones (9 total!)
• Has two parts Anterior Pituitary and Posterior
  Pituitary

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Remember the acronym MAP TO FLAG to
remember the nine pituitary hormones
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• The pituitary sits just below the hypothalamus
  which regulates the anterior pituitary by
  secreting neurosecretory hormones that can
  stimulate or inhibit the actions of it

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Hormones of the hypothalamus and pituitary glands
Nerve cells that release hormones into the blood
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ANTERIOR PITUITARY

• Secretes seven hormones
• Growth Hormone (GH) stimulates bone and muscle
  growth
• Adrenocorticotropic Hormone (ACTH) stimulates the
  adrenal cortex to secrete hormones
  (corticosteroids)

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ADRENAL CORTEX

• ACTH causes the adrenal cortex to produce its
  different hormones
• Glucocorticoids target the liver and promote
  the release of glucose

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Adrenal Cortex

• Mineralcorticoids target the kidney and promote
  the retention of water
• Ex Aldosterone increases recovery of Na and
  increases excretion of K and H ions into the
  urine

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Thyroid-Stimulating Hormone (TSH)
Anterior Pituitary Gland

• Stimulates the thyroid to secrete thyroxine
• Follicle-Stimulating Hormone (FSH)
• Stimulates the follicle to grow in females,
  oogenesis, and spermatogenesis

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Luteinizing Hormone
Anterior Pituitary Gland

• Causes the release of the ovum during the
  menstrual cycle in females and testosterone
  production in males

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Prolactin
Anterior Pituitary Gland

• Stimulates the mammary glands to produce milk

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Anterior Pituitary Gland
Melanocyte-Stimulating Hormone (MSH) Regulates
skin color in lower vertebrates, although its
function in humans is unknown
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Posterior Pituitary Gland

• Secretes Two Hormones (made by hypothalamus)
• Antidiuretic Hormone (ADH)
• acts on the kidneys, increasing
• water retention and thus decreasing urine volume.

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Posterior Pituitary Gland

• Oxytocin is secreted by the stimulation of the
  nipples
• during breast feeding and sexual intercourse it
  also stimulates uterine contractions during labor

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ADRENAL GLANDS

• Adrenal Medulla secretes epinephrine
  (adrenaline) and norepinephrine(noradrenaline)fig
  ht-or-flight response increase HR, BP,
  metabolism, etc

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Glucose homeostasis maintained by insulin and
glucagon
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THE PANCREAS

• Glucagon stimulates the liver to convert
  glycogen into glucose and to release that glucose
  into the blood
• Insulin has the opposite effect of glucagon

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Major Vertebrate Endocrine Glands and Some of
Their Hormones
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Major Vertebrate Endocrine Glands and Some of
Their Hormones (PancreasThymus)
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What is the advantage of having both a nervous
system and an endocrine system? What does the
hormone thyroxine affect?
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What is one effect of an iodine deficient diet?
Insulin stimulates cell to remove sugar from
the blood while ___________ stimulates the
release of glucose from cells.
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A shortage of dietary iodine makes it impossible
for the thyroid gland to produce thyroxine.
What would happen to blood levels of
thyroxine and the thyroid gland as a result? The
role of ADH is to
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What is the difference between Type I and Type II
diabetes?
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• The thyroid also increases the concentration of
  calcitonin which decreases the bloods
  concentration of calcium.