Pineal Parenchyma

**Semantic type:** Tissue

**Definition:** The tissue of the pineal gland. The pineal gland is a small reddish-gray body, about 8 mm. in length which lies in the depression between the superior colliculi. It is attached to the roof of the third ventricle near its junction with the mid-brain. It develops as an outgrowth from the third ventricle of the brain. The pineal parenchyma consists of follicles lined by epithelium and enveloped by connective tissues. It produces and secretes melatonin.