Topic 79 - MSH and the pineal gland Flashcards

1
Q

Words to include in MSH

A
  • Melanocyte-Stimulating Hormone (MSH)
  • Discoloration
  • Alpha MSH
    • ACTH
  • Beta MSH
    • Lipotropin
  • Gamma MSH
    • N-terminal of POMC
  • Pigment cells
    • Microtubule system
    • Microtubule matrix system
    • Pigment granules
    • Nucleus
    • Motor proteins
    • Pigment
    • Pigment synthesis
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2
Q

Words to include in pineal gland

A
  • Caudo-dorsally from hypothalamus
  • Pinealocytes
  • Glia cells
  • Serotonin
    • Light exposure
    • Darkness (+)
    • Daylight (÷)
    • Sexual activity (+ / ÷)
  • Melatonin
  • Synthesized
  • Innervation
    • C.P
    • Sypathetic cervical ggl.
    • Spinal cord
    • PH: SCN
    • Eye: retina
    • Light intensity ↓
    • Pineal body
    • Ectodermal structure
    • Diencephalon
  • NAT+
  • cAMP
  • AMP
  • Beta-receptor
  • Adenylate cyclase
  • Norepinephrine
  • Synthesis and release of melatonin
    • Serotonin
    • N-acetylserotonin
    • NAT (N-acetyl-transferase)
    • AcCoA
    • CoA
    • HIOMT (Hydroxyl-indol-O-methyl-transferase)
    • Degradation
    • Liver
    • Kidney
    • 6-hydroxymelatonin conjugates
    • Central nervous
    • N-acetyl-5-metoxy-kinurenamine
  • Function of melatonin
    • Pigment granulse
    • Sexual function
      • Sexual maturation (humans)
      • GnRH-FSH-LH axis
      • Sexual cycle (↑ / ↓)
      • Ovulation (humans)
    • Psycic effects
    • Free radicals
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3
Q

Topics to include in the essay

A
  1. MSH general
    • Effect of MSH on the pigment cells
  2. Pineal gland
    • Location
    • Composed of
    • Innervation of pineal gland
    • Serotonin
    • Melatonin
      • Synthesis and release of melatonin
      • Function of melatonin
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4
Q

What does MSH stand for?

A

Melanocyte-stimulating hormone

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5
Q

Types of MSH

A
  • Alpha-MSH
    • Formed from ACTH
  • Beta-MSH
    • Formed by beta lipotropin
  • Gamma-MSH
    • Cleaved by the N-terminal of POMC
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6
Q

Effect of MSH

A
  • Effect of MSH on the pigment cells
    • From the nucleus of pigment cells to the periphery there is a microtubule system arranged in a radial symmetry. In resting state, pigment granules are located around the nucleus
    • MSH exerts the migration of pigment granules along the microtubule matrix system, which is a process connected to the activation of motor proteins
    • The pigment is evenly distributed in the cell, and the cell or tissue becomes darkened
    • MSH facilitates pigment synthesis
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7
Q

Pineal gland

Location

A
  • Located caudo-dorsally from hypothalamus
  • Pineal gland is an ectodermal structure in the diencephalon
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8
Q

Pineal gland

What is the pineal gland composed of

A
  • Pinealocytes
  • Glia cells
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9
Q

Pineal gland

What is synthesized in the pineal gland

A
  1. Serotonin
  2. Melatonin
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10
Q

Pineal gland

Innervation

A

Decreasing of the effect of light form the environment (night) influences pineal body by a path shunting the CNS

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11
Q

Pineal gland

Melatonin production

A
  • Melatonin production has a circadian rhythm which depends on light exposure
    • Darkness acts positively on melatonin production
    • Strong illumination (daytime) acts negatively on melatonin production
  • In some species melatonin production positively influences sexual activity.
  • In others species melatonin production has a negative effect (on the initiation of follicular phase of female sexual cycle)
  • Melatonin has also a role in the binding to active radicals
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12
Q

Pineal gland

Synthesis and release of melatonin

A
  • Light exposure changes endocrine activity of pineal gland
  • Pineal body is considered as an endocrine transductor
    • It translates effects of light to the language of endocrinology
  • In light
    • Serotonin production starts
  • Lack of light
    • Melatonin is produced
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13
Q

Pineal gland

Function of melatonin

A
  • Melatonin in the skin has an effect opposite to MSH:
    • it induces concentration of pigment granules and the skin becomes pale
  • In mammals, three important effects of melatonin can be separated:
    • Sexual function
      • Inhibit sexual maturation (humans)
      • Inhibit GnRH-FSH-LH axis
      • Human ovulation
      • Increase sexual cycle in cat and horse
      • Decrease sexual cycle in sheep and goat
    • Psychic effects
      • Increased depression, appetite, sleepiness
      • Jet lag
  • Defense against free radicals
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