Anatomy, Histology and general pathology of the Pineal gland. Uri Shiri 1 st year, Int. medicine B

Transcription

1 Anatomy, Histology and general pathology of the Pineal gland Uri Shiri 1 st year, Int. medicine B

2 The Pineal gland A small, ~8mm sized Endocrine gland.

3 The Pineal gland A small, ~8mm sized Endocrine gland. Produces A Water soluble Product Melatonin.

4 The Pineal gland A small, ~8mm sized Endocrine gland. Produces A Water soluble Product Melatonin. Melatonin regulates important biological functions, including:

5 The Pineal gland A small, ~8mm sized Endocrine gland. Produces A Water soluble Product Melatonin. Melatonin regulates important biological functions, including: -sexual maturity (by inhibiting gonadal development and delaying onset of puberty)

6 The Pineal gland A small, ~8mm sized Endocrine gland. Produces A Water soluble Product Melatonin. Melatonin regulates important biological functions, including: -sexual maturity (by inhibiting gonadal development and delaying onset of puberty) -Circadian rhythm

7 The Pineal gland A small, ~8mm sized Endocrine gland. Produces A Water soluble Product Melatonin. Melatonin regulates important biological functions, including: -sexual maturity (by inhibiting gonadal development and delaying onset of puberty) -Circadian rhythm -Antioxidant, etc

8 General Anatomy

9 General Anatomy

10 General Anatomy situated in subarachnoid space behind third ventricle, below splenium of corpus callosum and origin of great vein of Galen, and above and between midbrain superior colliculi

11 General Anatomy situated in subarachnoid space behind third ventricle, below splenium of corpus callosum and origin of great vein of Galen, and above and between midbrain superior colliculi Coronaly situated just above the plane of the eyes.

12 Regulation of Circadian cycle: The Pineal gland as the 3 rd eye

13 Regulation of Circadian cycle: The Pineal gland as the 3rd eye The Pineal gland may be considered as the 3 rd eye, being a Photosensitive organ.

14 Regulation of Circadian cycle: The Pineal gland as the 3rd eye The Pineal gland may be considered as the 3 rd eye, being a Photosensitive organ. Light signals travel from the Retina via the Retinohypothalamic system to the Suprachiasmatic nuclei (SCN) and to the pineal gland.

15 Regulation of Circadian cycle: The Pineal gland as the 3rd eye The Pineal gland may be considered as the 3 rd eye, being a Photosensitive organ. Light signals travel from the Retina via the Retinohypothalamic system to the Suprachiasmatic nuclei (SCN) and to the pineal gland. High Melatonin conc. Results in drowsiness.

16 Regulation of Circadian cycle: The Pineal gland as the 3rd eye The Pineal gland may be considered as the 3 rd eye, being a Photosensitive organ. Light signals travel from the Retina via the Retinohypothalamic system to the Suprachiasmatic nuclei (SCN) and to the pineal gland. High Melatonin conc. Results in drowsiness. Melatonin production is inhibited by the presence of light.

17 General Histology

18 General Histology A lobulated, parenchymal organ.

19 General Histology A lobulated, parenchymal organ. The main secreting cells are called Pinealocytes, which produce Melatonin.

20 General Histology A lobulated, parenchymal organ. The main secreting cells are called Pinealocytes, which produce Melatonin. Melantonin is secreted into the Pineal capillaries.

21 General Histology A lobulated, parenchymal organ. The main secreting cells are called Pinealocytes, which produce Melatonin. Melantonin is secreted into the Pineal capillaries. Blood Brain Barrier is not present in this area.

22 General Histology

23 Some Pathologies

24 Some Pathologies Pineal calcification - calcification of ground substance secreted by pineocytes begins in childhood and increases with age

25 Some Pathologies Pineal calcification - calcification of ground substance secreted by pineocytes begins in childhood and increases with age useful for identifying pineal region on radiographic studies

26 Some Pathologies Pineal cysts - small cysts lined by proliferation of astrocytes with prominent Rosenthal fibers

27 Some Pathologies Pineal cysts - small cysts lined by proliferation of astrocytes with prominent Rosenthal fibers (Eosinophilic residues present in several pathological brain conditions)

28 Some Pathologies Pineal neoplasms

29 Some Pathologies Pineal neoplasms Germ Cell tumors (Pineocytoma, Pineoblastoma) - Tumors of the parenchymal cells- Glioma- Metastatic secondary tumors which may travel - via the capillaries, due to lack of blood brain barrier.

30 Signs and symptoms of pineal tumors:

31 Signs and symptoms of pineal tumors: Pineal tumors often compress the Aquaduct of Sylivius, Which allows passage of CSF from the center of the brain.

32 Signs and symptoms of pineal tumors: Pineal tumors often compress the Aquaduct of Sylivius, Which allows passage of CSF from the center of the brain. The result is increased pressure of the fluid in the brain hydrocephalus

33 Signs and symptoms of pineal tumors: Pineal tumors often compress the Aquaduct of Sylivius, Which allows passage of CSF from the center of the brain. The result is increased pressure of the fluid in the brain hydrocephalus This phenomenon is accompanied by Headaches Seizures Nausea and vomitting Memory disturbances Impaired vision

34 Increased intracranial pressure may reach life threatening levels!

35 Treatments

36 Treatments A Hydrocephalus may be treated using a VP shunt. Fluid is drained into the peritoneal space.

37 Treatments A Hydrocephalus may be treated using a VP shunt. Fluid is drained into the peritoneal space. An alternative treatment is stereotactic third ventriculostomy.

38 Treatments As for the tumor itself: Surgery is essential to obtain a sample of the tumor tissue so the pathologist can determine precise histological diagnosis. Benign tumors can be removed surgically. The most common malignancy in this region is germinoma, which can be cured with high probability. Other malignancies can be cured by chemotherapy followed radiation therapy.