Final answer:
Arachnoid granulations are responsible for the absorption of CSF back into the bloodstream, which is essential for maintaining fluid balance, cushioning the CNS, and removing waste.
Step-by-step explanation:
The function of arachnoid granulations is the absorption of cerebrospinal fluid (CSF) back into the bloodstream. These granulations are specialized structures that emerge from the arachnoid mater into the dural sinuses, allowing CSF to flow from the subarachnoid space into the venous system. This process is crucial for maintaining the balance of CSF production and reabsorption, thus ensuring the cerebrospinal fluid effectively cushions the central nervous system (CNS) and removes metabolic wastes.
The cerebrospinal fluid circulates around the brain and spinal cord, acting as a protective liquid cushion. It also serves to circulate nutrients and remove waste products from the CNS. Without the proper function of arachnoid granulations, there could be an imbalance, potentially leading to conditions such as hydrocephalus, where excess CSF accumulates and may cause increased pressure on the brain.