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Chapter 45 Hormones

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									            Ch. 45 Objectives
•   Define hormone
•   Differentiate betw. steroid & non-steroid
•   Differentiate betw. tropic & non-tropic
•   Explain role of hypothalamus & pituitary
•   Describe relationship among glands
                 Checklist
•   Location of endocrine glands
•   Origin of hormones
•   Function of hormones
•   Complementary pairs of hormones
•   What regulates hormones?
•   Why do some tissues respond, not others?
              Hormones:
• Chemicals that are produced in one part of
  the body, travel through the circulatory
  system to another part where they exert
  some control
      Internal Communication &
              Regulation
• Via nervous & endocrine systems
  – Nervous: electrical signals / neurons / fast
  – Endocrine: chemical signals / bloodstream /
    slower, longer-lasting
• Some overlap:
  – Nerve cells release hormones
  – Chemicals can be hormone and
    neurotransmitter
Signaling
Molecules
Hormone Type / Receptor Location
• Water-soluble
  – Polypeptides & amines
  – Plasma membrane
  – Cellular response


• Fat-soluble
  – Steroids, others
  – Intracellular
  – Nuclear response
    (transcription)
Fig. 45.3
       One signal, different effects
• Target cells may
  have:
  – Different receptors
  – Different STPs
  – Different response
    chemicals
Another Way to Classify Hormones
• Tropic:                   • Non-tropic:
   – Those that cause the     – Those that do
     release of another         something else, e.g.,
     hormone                    lower glucose level,
• AKA “Releasing                reduce blood calcium
                                level
  factors”, ____-tropins,
  _____-tropic
  hormone,
  hypothalamic
  hormones (Table
  45.1)
Control of
 Blood
Glucose
 Level
• 2 antagonistic
  hormones
• Pancreas:
  endocrine gland
• Target tissues
• Tight control
       Hypothalamus Integrates
          Endocrine System
• Part of brain
• Closely tied to
  pituitary
• Receives & sends
  chem., electrical
  signals
            Pituitary Gland(s)
• Posterior: Extension
  of hypothalamus
  – Neural tissue
  – Stores, secretes
    neurohormones
     • ADH
     • Oxytocin
  Posterior Pituitary Hormones
• ADH = antidiuretic hormone
  – Acts on kidneys
  – Increases water retention
  – Made in hypothalamus
• Oxytocin
  – Acts on uterus, mammary glands
  – Induces muscle contraction, milk ejection
  – Made in hypothalamus
  – Exhibits positive feedback
  Pituitary Gland(s) (continued)

• Anterior: from roof of
  embryonic mouth
   – Epithelial tissue
   – Produces, secretes
     many hormones
      • Tropic
      • Non-tropic
   – Regulated by
     hypothalamus
      • “Releasing factors”
      • Portal system
        Tropic, tropisms, etc
• Tropism = growth response
  – E.g., geotropism, phototropism


• Tropic hormones: those that stimulate
  growth (specifically hormone prod’n) in
  target tissue
      Anterior Pituitary, cont’d
• “Releasing factors”
  from hypothal. are
  tropic hormones

• Portal system =
  capillary networks in
  series, w/o first
  returning to heart.
   Anterior Pituitary Hormones
• Tropic             • Nontropic
  –   FSH              – Prolactin
  –   LH               – MSH
  –   TSH
  –   ACTH

  – Growth Hormone     – Growth Hormone
      Anterior Pituitary: Tropic
• FSH = Follicle-Stimulating Hormone AND
• LH = Luteinizing Hormone
  – Act on gonads (“gonadotropin”)
  – Stimulate prod’n of estrogens, androgens
• TSH = Thyroid-Stimulating Hormone
  – Acts on thyroid gland
  – Stimulates gland dev’ment
  – Promotes prod’n of thyroid hormones
• ACTH = Adreno-Cortico-Tropic-Hormone
  – Acts on adrenal gland
  – Stimulates prod’n of adrenal-cortex hormones
  Anterior Pituitary: Non-tropic
• Prolactin
  – Acts on mammary glands
  – Stimulates milk prod’n (mammals)


• MSH = melanocyte-stimulating hormone
  – Acts on brain (mammals)
  – Inhibits hunger (mammals)
     GH: Tropic & Non-tropic
• Tropic: Stimulates liver to release IGFs
  – Effect on bone, cartilage


• Non-tropic: metabolic effects, e.g.,
  • ↑ blood glucose
  • ↑ muscle growth
  • ↑ fat breakdown
      Non-pituitary Hormones
• Thyroid
  – T3 & T4, calcitonin
• Parathyroid
  – PTH
• Pancreas
  – Insulin & Glucagon
• Adrenal Medulla
  – Epinephrine &
    norepinephrine
  More Non-pituitary Hormones
• Adrenal Cortex
  – Glucocorticoids
  – Mineralocorticoids
• Gonads
  – Androgens
    (testosterone)
  – Estrogens (estradiol)
  – Progestins
    (progesterone)
• Pineal Gland
  – Melatonin
Anterior Pituitary: Growth Hormone
 • Tropic Effects:
   – Acts on liver
   – Stimulates prod’n of IGFs which affect bone
 • Non-tropic Effects:
   – Affects metabolism throughout body
   – Affects blood glucose levels
  Non-Pituitary: Thyroid Gland
• 2 lobes
• In front of trachea
• Produce 3 hormones:
  – T3 & T4
     •   (NOT antagonistic)
     •   Bone growth
     •   Nerve cells
     •   Metabolism
     •   Iodine needed

  – Calcitonin
     • Calcium homeostasis
     • Acts on bone, kidneys
 Non-Pituitary: Parathyroid Glands
• Embedded on surface
  of thyroid
• Produces PTH =
  parathyroid hormone
• Function: Ca
  homeostasis
  – Acts on Bone, kidneys
• Antagonistic to
  Calcitonin
      Non-Pituitary: Pancreas
• Behind Stomach, duct
  to SI
• Endocrine & exocrine
• Endocrine Function:
  – Islets of Langerhans
     • Glucagon
     • Insulin
• Functions: storage &
  release of sugar
  Non-Pituitary: Adrenal Glands
• Perched on top of kidneys
• Overall Function: Stress
  Response
• Each is really 2 glands:
   – Adrenal Cortex
      • Outer layer
      • Stim. By ACTH
      • Mineralocorticoids,
        glucocorticoids
   – Adrenal Medulla
      • Inner layer
      • Stim. By nervous system
      • Epinephrine, norepinephrine
   Non-Pituitary: Gonadal Hormones
• Testes (male), Ovaries
  (female)
• Functions:
  – Dev’ment of sex organs
  – Dev’ment of 2˚ sex
    characteristics
  – Regulate repro. Cycles
  – Regulate behavior
• Hormones:
  – Androgens (testosterone)
  – Estrogens (estradiol)
  – Progestins (progesterone)
    Non-pituitary: Pineal Gland
• In Brain
• Functions:
  – Skin pigmentation
  – Biorhythms
     • E.g., sleep, temp
• Melatonin
   Match Hormone w/ Source
Hormones           Sources

_____Glucagon      A. Hypothalamus

_____T3            B. Anterior Pituitary

_____Oxytocin      C. Adrenal medulla

_____ACTH          D. Thyroid

_____Epinephrine   E. Pancreas
1. How is a hormone different from a
   neurohormone?
2. What is a tropic hormone? An example?
3. Which kind of organ is the main target for
   tropic hormones?
4. What is an example of hormones that are
   antagonistic to each other?
5. If a gland doesn’t receive “instructions” to
   release hormone from a tropic hormone, then
   what does tell it to release hormone?
6. How is anterior pituitary different from posterior
   pituitary? How are they the same?
1. Which hormone might be produced in
   response to a change in blood Ca level?
2. Which organ will be stimulated to
   produce a hormone in response to
   stress?
3. Where is ACTH produced?
4. Hyperthyroidism is a disorder of which
   gland?
5. Why are the capillaries around the ant.
   Pituitary called a portal system?
6. Name one gonadotropic hormone.

								
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