Pineal body Flashcards
1
Q
Embryonic origin of Pineal body
A
neuroectoderm
2
Q
pineal body is attached to ____ by ____
A
- third ventricle
- pineal stalk
3
Q
covering of pineal body
A
Pia mater
* gives rise to septa containing unmyelinated nerve fibers & blood vessels
* the septa divides the pineal body into incomplete lobules
4
Q
contents of Pineal body
A
- Pinealocytes
- Astrocytes
- Fenestrated blood capillaries
- Brain sand (psammoma bodies & corpora aranacea)
5
Q
LM of pinealocytes
A
- Basophilic cytoplasm
- Long processes ending by dilatations onto blood capillaries
- large pale nucleus with clear nucleolus
6
Q
Innervation of pinealocytes
A
- by unmyelinated nerve fibers releasing noradrenaline
7
Q
function of Pinealocytes
A
- Secrete serotonin (in the morning)
- Secrete Melatonin (in the night)
8
Q
function of melatonin
A
- Regulate gonadal function (prevents precocious puberty)
- Regulate sleep rhythm
- Antioxidant
9
Q
difference between astrocytes & pinealocytes
A
- astrocytes have a darker nucleus
- Astrocytes are neuroglial cells
10
Q
components of brain sand (psamomma bodies/ Corpa aranacea)
A
calcified concretions that increase by age
11
Q
clincal significance of Brain sand
A
it’s used in X ray as a landmark to localize any mass in the brain
