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    From Nervous System

    Foramen of Magendie
    Median aperture of fourth ventricle.
    Vermis
    Midline structure of the cerebellum.
    Corpus Callosum
    Connects the left and right cerebral hemispheres.
    Cerebrospinal Fluid (CSF)
    Protective fluid in brain and spinal cord.
    Dorsal Root Ganglion
    Contains sensory neuron cell bodies.
    Medulla Oblongata
    Controls autonomic functions like breathing and heart rate.
    Lumbar Spinal Cord
    Lower portion of the spinal cord.
    Fornix
    Fiber tract involved in memory.
    Lateral Ventricles
    Paired brain cavities producing CSF.
    Filum Terminale
    Fibrous extension from conus to coccyx.
    Infundibulum
    Connects hypothalamus to pituitary gland.
    Tentorium Cerebelli
    Separates cerebellum from cerebrum.
    Pons
    Connects upper and lower parts of the brain.
    Frontal Lobe
    Controls reasoning, planning, movement, emotions, and problem-solving.
    Occipital Lobe
    Responsible for visual processing.
    Parietal Lobe
    Processes sensory information such as touch, temperature, and pain.
    Sacral Plexus
    Nerve network for pelvis and lower limb.
    Brachial Plexus
    Nerve network for the upper limb.
    Diaphragma Sellae
    Covers the pituitary gland.
    Cerebellar Hemispheres
    Lateral portions of the cerebellum.
    Third Ventricle
    Midline cavity of the diencephalon.
    Spinal Cord
    Transmits neural signals between brain and body.
    Cerebellum
    Coordinates movement and balance.
    Cerebellar Peduncles
    Connect the cerebellum to the brainstem.
    Arbor Vitae
    White matter of the cerebellum.

    Pituitary Gland

    Reviewed by our medical team

    Endocrine gland controlling other hormone glands.

    1. Overview

    The pituitary gland, often referred to as the "master gland," is a small, pea-sized endocrine gland located at the base of the brain. It plays a critical role in regulating various physiological processes by secreting hormones that control the function of other endocrine glands, including the thyroid, adrenal glands, and gonads (testes and ovaries). The pituitary gland is essential for growth, metabolism, reproduction, and stress response. It is connected to the hypothalamus via the pituitary stalk, which facilitates the release of hormones in response to signals from the brain. Because of its central role in hormone regulation, the pituitary is often considered the most important gland in the endocrine system.

    2. Location

    The pituitary gland is located in a bony depression at the base of the skull known as the sella turcica, which is part of the sphenoid bone. It sits beneath the hypothalamus and is connected to it by the pituitary stalk (also called the infundibulum), which allows for the communication of hormonal signals. The gland lies just behind the optic chiasm (where the optic nerves cross) and above the nasopharynx. This central position in the brain allows the pituitary gland to coordinate the activity of several other endocrine glands and control a wide range of physiological functions in the body.

    3. Structure

    The pituitary gland is structurally divided into two main parts: the anterior pituitary and the posterior pituitary, each with distinct functions and hormone secretions.

    • Anterior pituitary (Adenohypophysis): The anterior pituitary is the larger of the two sections and is responsible for producing and secreting a variety of hormones that regulate other endocrine glands. These hormones include:

      • Growth hormone (GH): Stimulates growth and cell reproduction.

      • Thyroid-stimulating hormone (TSH): Stimulates the thyroid gland to release thyroid hormones.

      • Adrenocorticotropic hormone (ACTH): Stimulates the adrenal glands to release cortisol and other hormones.

      • Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH): Regulate the function of the gonads (testes and ovaries).

      • Prolactin (PRL): Stimulates milk production in the mammary glands.

    • Posterior pituitary (Neurohypophysis): The posterior pituitary does not produce hormones but stores and releases hormones produced by the hypothalamus. These hormones include:

      • Oxytocin: Involved in uterine contractions during childbirth and milk ejection during breastfeeding.

      • Antidiuretic hormone (ADH, also called vasopressin): Regulates water balance by increasing water reabsorption in the kidneys and reducing urine output.

    • Pituitary stalk: The pituitary stalk is a thin structure that connects the hypothalamus to the pituitary gland. It serves as a conduit for the transport of hormones from the hypothalamus to the pituitary, enabling the communication between these two critical brain structures.

    4. Function

    The pituitary gland functions primarily as a control center for hormone regulation in the body. Its key functions include:

    • Endocrine regulation: The pituitary gland regulates the function of several other endocrine glands by releasing hormones that stimulate or inhibit their activity. For example, TSH stimulates the thyroid to produce thyroid hormones, while ACTH stimulates the adrenal glands to release cortisol.

    • Growth regulation: Growth hormone (GH) produced by the anterior pituitary plays a crucial role in regulating growth and development by stimulating the growth of bones, muscles, and tissues throughout the body.

    • Reproduction: The anterior pituitary secretes luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are vital for the regulation of the reproductive system. These hormones control the menstrual cycle in females and sperm production in males.

    • Water balance and osmoregulation: Antidiuretic hormone (ADH), produced by the hypothalamus and released by the posterior pituitary, helps regulate the body’s water balance by promoting water reabsorption in the kidneys. This helps maintain blood pressure and prevents dehydration.

    • Milk production: Prolactin, another hormone produced by the anterior pituitary, stimulates the mammary glands to produce milk following childbirth.

    • Stress response: The pituitary gland, through the secretion of ACTH, helps regulate the body's response to stress by stimulating the release of cortisol from the adrenal glands. Cortisol is essential for the body’s fight-or-flight response and helps manage energy levels during stressful situations.

    5. Physiological Role(s)

    The physiological roles of the pituitary gland are critical for maintaining homeostasis and supporting the normal functioning of the body’s endocrine system. Some of its primary physiological roles include:

    • Growth and development: Through the secretion of growth hormone (GH), the pituitary gland plays a key role in physical growth and development, especially during childhood and adolescence. GH stimulates the growth of bones, cartilage, and soft tissues, contributing to overall body size and strength.

    • Metabolism regulation: The pituitary's regulation of thyroid hormones (via TSH) and adrenal hormones (via ACTH) influences metabolism, energy production, and stress response. These hormones control the body's use of nutrients and help maintain stable blood sugar levels, energy, and temperature.

    • Water and electrolyte balance: The secretion of ADH by the posterior pituitary plays a central role in regulating the body’s hydration status. ADH helps control the amount of water reabsorbed by the kidneys, which in turn influences urine concentration and volume, blood pressure, and fluid balance.

    • Reproductive function: The pituitary gland’s secretion of LH and FSH regulates reproductive functions, including ovulation and sperm production. These hormones control the menstrual cycle, stimulate the production of eggs and sperm, and maintain fertility in both males and females.

    • Emotional regulation: Oxytocin, secreted by the posterior pituitary, is involved in bonding, emotional responses, and social interactions. It plays a role in childbirth (by stimulating uterine contractions) and breastfeeding (by promoting milk ejection), and it has been linked to maternal behaviors and social bonding.

    6. Clinical Significance

    The pituitary gland is clinically significant because it is involved in a wide range of physiological processes, and its dysfunction can lead to various endocrine disorders. Some key clinical conditions related to pituitary dysfunction include:

    • Pituitary tumors (Pituitary adenomas): Tumors of the pituitary gland can cause an overproduction or underproduction of pituitary hormones. These tumors can lead to conditions such as acromegaly (overproduction of growth hormone), Cushing's disease (excess cortisol production), or hypopituitarism (insufficient hormone production). Pituitary tumors are often treated with surgery, radiation therapy, or medications.

    • Growth hormone disorders: Disorders of growth hormone secretion can lead to either gigantism or acromegaly (excess GH) or dwarfism (insufficient GH). These conditions are typically caused by pituitary tumors or malfunctions of the hypothalamic-pituitary axis.

    • Diabetes insipidus: Diabetes insipidus is a condition characterized by excessive thirst and urination, caused by a deficiency in antidiuretic hormone (ADH) or a lack of response to ADH. This condition can result from damage to the pituitary gland or hypothalamus, disrupting the regulation of water balance.

    • Hypopituitarism: Hypopituitarism is a condition where the pituitary gland does not produce enough of one or more of its hormones. It can lead to a variety of symptoms, including fatigue, weight gain, infertility, and delayed growth in children. This condition can be caused by pituitary tumors, trauma, infections, or autoimmune diseases.

    • Sheehan's syndrome: Sheehan's syndrome is a rare condition that occurs after severe blood loss during childbirth, leading to damage to the pituitary gland. This results in the failure of pituitary hormone production, leading to symptoms such as fatigue, lack of menstruation, and an inability to produce breast milk.

    • Hyperprolactinemia: Overproduction of prolactin, a hormone responsible for milk production, can occur due to pituitary tumors or other factors, leading to symptoms such as irregular menstruation, infertility, and galactorrhea (milk production unrelated to childbirth).

    The pituitary gland plays a central role in regulating a wide variety of physiological processes, from growth and reproduction to metabolism and water balance. Disruptions in pituitary function can result in a range of endocrine disorders, highlighting the importance of this small yet powerful gland. Early diagnosis and treatment are essential for managing these conditions and improving patient outcomes.

    Did you know? The average adult brain weighs about 1.4 kilograms (3 pounds).