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
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
3
Q
Topics to include in the essay
A
- MSH general
- Effect of MSH on the pigment cells
- Pineal gland
- Location
- Composed of
- Innervation of pineal gland
- Serotonin
- Melatonin
- Synthesis and release of melatonin
- Function of melatonin
4
Q
What does MSH stand for?
A
Melanocyte-stimulating hormone
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
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
7
Q
Pineal gland
Location
A
- Located caudo-dorsally from hypothalamus
- Pineal gland is an ectodermal structure in the diencephalon
8
Q
Pineal gland
What is the pineal gland composed of
A
- Pinealocytes
- Glia cells
9
Q
Pineal gland
What is synthesized in the pineal gland
A
- Serotonin
- Melatonin
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
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
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
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
-
Sexual function
- Defense against free radicals
