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    From Nervous System

    Ventral Root
    Carries motor information from spinal cord.
    Arbor Vitae
    White matter of the cerebellum.
    Conus Medullaris
    Terminal end of the spinal cord.
    Tectum
    Dorsal part of midbrain controlling visual and auditory reflexes.
    Choroid Plexus
    Produces cerebrospinal fluid.
    Cranial Nerves
    Twelve pairs of nerves that emerge from the brain.
    Dura Mater
    Tough outer meningeal layer.
    Medulla Oblongata
    Controls autonomic functions like breathing and heart rate.
    Foramen of Magendie
    Median aperture of fourth ventricle.
    Dorsal Root Ganglion
    Contains sensory neuron cell bodies.
    Sacral Spinal Cord
    Bottom portion of the spinal cord.
    Tentorium Cerebelli
    Separates cerebellum from cerebrum.
    Hypothalamus
    Regulates autonomic functions, hormones, and homeostasis.
    Thalamus
    Relay station for sensory and motor signals to the cerebral cortex.
    Foramina of Luschka
    Lateral apertures of fourth ventricle.
    Hippocampus
    Essential for memory formation.
    Infundibulum
    Connects hypothalamus to pituitary gland.
    Subarachnoid Space
    Contains cerebrospinal fluid.
    Fornix
    Fiber tract involved in memory.
    Pituitary Gland
    Endocrine gland controlling other hormone glands.
    Sympathetic Chain
    Series of ganglia for sympathetic nervous system.
    Cerebral Cortex
    Outer layer of cerebrum responsible for complex thought processes.
    Cervical Spinal Cord
    Upper part of the spinal cord.
    Cingulate Gyrus
    Processes emotions and behavior regulation.
    Arachnoid Mater
    Middle meningeal layer.

    Diaphragma Sellae

    Reviewed by our medical team

    Covers the pituitary gland.

    1. Overview

    The diaphragma sellae is a thin, flat, dural membrane that forms a roof over the pituitary gland, which is housed within the sella turcica of the sphenoid bone in the skull. It acts as a protective covering for the pituitary gland and helps to separate it from the rest of the brain. The diaphragma sellae is part of the dura mater, one of the three meninges that surround and protect the brain and spinal cord. This structure is crucial for the proper functioning of the pituitary gland and the regulation of hormonal secretion from it.

    2. Location

    The diaphragma sellae is located in the center of the base of the skull, directly over the pituitary gland. It forms the roof of the sella turcica, a bony cavity within the sphenoid bone that houses the pituitary gland. The diaphragma sellae is part of the dura mater, the outermost layer of the meninges, and it extends from the anterior and posterior clinoid processes of the sphenoid bone to create a barrier over the pituitary gland. It also surrounds the pituitary stalk, which connects the pituitary gland to the hypothalamus in the brain.

    3. Structure

    The diaphragma sellae is a thin, circular membrane that is made up of fibrous tissue. Its structure can be described as follows:

    • Shape: The diaphragma sellae is generally described as a flat, circular, or slightly oval membrane that spans the upper portion of the sella turcica, forming a roof over the pituitary gland.

    • Composition: The diaphragma sellae is composed of dense connective tissue and is covered by a layer of dural tissue. It is part of the dura mater, which is the tough, fibrous outer layer of the meninges that protect the brain and spinal cord.

    • Pituitary stalk: The diaphragma sellae has a central opening through which the pituitary stalk passes. The pituitary stalk is a slender, neural structure that connects the pituitary gland to the hypothalamus and allows for the transport of hormones and signals between these two structures.

    • Attachments: The diaphragma sellae is attached to the bony structures of the skull, specifically the anterior and posterior clinoid processes of the sphenoid bone. These attachments help to stabilize the diaphragm and support its role as a protective barrier over the pituitary gland.

    4. Function

    The primary function of the diaphragma sellae is to protect and support the pituitary gland. Key functions include:

    • Protective barrier: The diaphragma sellae forms a physical barrier that separates the pituitary gland from the rest of the brain, providing protection from injury or pressure from other brain structures.

    • Support for the pituitary stalk: The central opening of the diaphragma sellae allows the pituitary stalk to pass through. This stalk connects the pituitary gland to the hypothalamus, enabling communication between these two important structures for hormone regulation.

    • Regulation of pituitary function: By maintaining a stable environment for the pituitary gland and its connections to the hypothalamus, the diaphragma sellae indirectly plays a role in regulating the release of hormones that control various physiological processes, such as metabolism, growth, and reproduction.

    5. Physiological Role(s)

    The physiological roles of the diaphragma sellae are essential for the normal functioning of the pituitary gland and the regulation of hormonal activity within the body. Some of the key physiological roles include:

    • Hormonal regulation: The pituitary gland, housed beneath the diaphragma sellae, is often referred to as the "master gland" due to its role in producing and secreting hormones that regulate various functions in the body, such as growth, reproduction, and metabolism. The diaphragma sellae provides physical support to the pituitary gland and facilitates its connection to the hypothalamus, which controls the release of pituitary hormones.

    • Communication between the hypothalamus and pituitary gland: The pituitary stalk, which passes through the diaphragma sellae, allows for the transfer of signals and hormones between the hypothalamus and the pituitary gland. This communication is vital for maintaining homeostasis and regulating functions such as body temperature, hunger, and stress responses.

    • Protection of the pituitary gland: The diaphragma sellae acts as a protective barrier, helping to shield the pituitary gland from external forces or pressure from surrounding brain structures. It ensures that the pituitary gland remains in a stable environment, essential for its function in regulating bodily processes.

    6. Clinical Significance

    The diaphragma sellae is clinically significant because any damage or abnormality in this structure can affect the pituitary gland and disrupt its function. Some clinical conditions related to the diaphragma sellae include:

    • Pituitary tumors: Tumors of the pituitary gland, such as pituitary adenomas, can cause compression of the diaphragma sellae and disrupt the normal function of the pituitary gland. This can lead to a variety of hormonal imbalances, including acromegaly, Cushing's disease, or hypopituitarism. Tumors can also cause pressure on the surrounding structures, leading to headaches, vision problems, or neurological deficits.

    • Diaphragma sellae abnormalities: In some cases, congenital abnormalities or structural defects in the diaphragma sellae can lead to problems with the pituitary gland or its connections to the hypothalamus. These abnormalities may contribute to hormonal disorders or developmental issues in children.

    • Sellar region infections: Infections affecting the sellar region, where the diaphragma sellae and pituitary gland are located, can lead to inflammation and dysfunction of the pituitary gland. This may result in conditions such as hypopituitarism, where the pituitary gland fails to produce sufficient hormones, affecting growth, metabolism, and reproductive function.

    • Sheehan's syndrome: Sheehan’s syndrome is a condition that can occur after severe blood loss during childbirth, leading to damage to the pituitary gland. It may also affect the diaphragma sellae and result in pituitary infarction, causing a decrease in hormone production and potentially leading to symptoms such as fatigue, inability to lactate, and menstrual irregularities.

    • CSF leakage: Damage to the diaphragma sellae or surrounding structures can lead to cerebrospinal fluid (CSF) leakage, which may result in conditions such as a cerebrospinal fluid fistula or intracranial hypertension. This can cause symptoms such as headaches, visual disturbances, and dizziness.

    The diaphragma sellae is a critical structure that protects and supports the pituitary gland and its connections to the hypothalamus. Dysfunction or damage to this structure can lead to a range of clinical conditions, particularly those involving hormonal imbalances or neurological complications. Early diagnosis and intervention are crucial for managing conditions that affect the diaphragma sellae and the pituitary gland.

    Did you know? The brain's storage capacity is said to be the equivalent of about 2.5 petabytes (or one million gigabytes).