Pituitary Gland Anatomy and Functions
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Questions and Answers

What is the primary arterial supply to the pancreas?

  • Celiac artery and inferior mesenteric artery
  • Renal arteries and hepatic artery
  • Splenic artery and pancreaticoduodenal arteries (correct)
  • Thoracic aorta and subclavian artery

    • Which cells in the Islets of Langerhans are responsible for producing insulin?

  • Gamma cells
  • Delta cells
  • Alpha cells
  • Beta cells (correct)

    • What happens to the thymus after puberty?

  • It remains the same size throughout life
  • It gradually reduces in size and is replaced by fatty tissue (correct)
  • It increases in size and function
  • It becomes hyperactive and enlarges

    • Which of the following correctly describes the morphology of the pancreas?

    <p>Possesses ducts for its exocrine function and is organized into lobules</p> Signup and view all the answers

    What is the function of the thymus gland?

    <p>To secrete hormones that regulate immune cell production</p> Signup and view all the answers

    What type of cells primarily populate the cortex of the thymus?

    <p>T lymphocytes (thymocytes)</p> Signup and view all the answers

    What is the primary function of Leydig cells in the testes?

    <p>Produce testosterone</p> Signup and view all the answers

    Which component is NOT found in the medulla of the thymus?

    <p>Basophilic epithelial cells</p> Signup and view all the answers

    What does the tunica albuginea refer to in both the testes and the ovaries?

    <p>The outer fibrous capsule</p> Signup and view all the answers

    What is a primary characteristic of Hassall's corpuscles?

    <p>They contain keratinized epithelial cells.</p> Signup and view all the answers

    What condition is associated with the accumulation of fluid in the tunica vaginalis?

    <p>Hydrocoele testis</p> Signup and view all the answers

    Which structure in the ovaries is responsible for hormone production?

    <p>Corpus luteum</p> Signup and view all the answers

    What changes in the thymus after puberty?

    <p>Lipid infiltration occurs</p> Signup and view all the answers

    What is the shape of the right adrenal gland?

    <p>Pyramidal</p> Signup and view all the answers

    Where does the left suprarenal vein drain?

    <p>Into the renal vein</p> Signup and view all the answers

    Which zone of the adrenal cortex is responsible for producing mineralocorticoids such as aldosterone?

    <p>Zona glomerulosa</p> Signup and view all the answers

    What is the histological characteristic of the zona fasciculata in the adrenal cortex?

    <p>Cells arranged in parallel cords</p> Signup and view all the answers

    What supplies blood to the adrenal glands?

    <p>Inferior phrenic artery</p> Signup and view all the answers

    Which adrenal cortex layer is known for secreting small amounts of sex hormones?

    <p>Zona fasciculata</p> Signup and view all the answers

    What type of fat surrounds the renal fascia?

    <p>Pararenal fat</p> Signup and view all the answers

    What is the venous drainage of the right suprarenal vein?

    <p>To the inferior vena cava</p> Signup and view all the answers

    What hormones are secreted by the adrenal medulla?

    <p>Adrenaline and noradrenaline</p> Signup and view all the answers

    What condition is characterized by hypoadrenalism due to autoimmune adrenalitis?

    <p>Addison's disease</p> Signup and view all the answers

    Which hormones are produced by the pineal gland?

    <p>Melatonin and serotonin</p> Signup and view all the answers

    What is a characteristic feature of chromaffin cells in the adrenal medulla?

    <p>Faintly basophilic cytoplasm with granules</p> Signup and view all the answers

    What is the function of the pineal gland in relation to light?

    <p>Synthesizes melatonin induced by darkness</p> Signup and view all the answers

    Which of the following describes Conn's syndrome?

    <p>Characterized by excessive production of aldosterone</p> Signup and view all the answers

    Which anatomical feature connects the pineal gland to the brain?

    <p>Neural stalk containing nerve fibers</p> Signup and view all the answers

    What is the primary function of the growth hormone produced by the anterior pituitary?

    <p>Acts on overall growth</p> Signup and view all the answers

    What is the role of adrenal medullary hormones during stress?

    <p>Increase physical and psychological alertness</p> Signup and view all the answers

    Which structure connects the pituitary gland to the hypothalamus?

    <p>Infundibulum</p> Signup and view all the answers

    What is the histological feature of chromophobes found in the pars distalis of the anterior pituitary?

    <p>Scanty cytoplasm and few granules</p> Signup and view all the answers

    Which hormone is primarily responsible for stimulating the interstitial cells of the testes?

    <p>Luteinizing hormone</p> Signup and view all the answers

    What is a common consequence of a pituitary adenoma producing excessive growth hormone?

    <p>Gigantism or acromegaly</p> Signup and view all the answers

    Which region of the pituitary gland secretes melanocyte stimulating hormone (MSH)?

    <p>Pars intermedia</p> Signup and view all the answers

    What role do pituicytes serve in the posterior pituitary?

    <p>Act as specialized neuroglial cells</p> Signup and view all the answers

    The failure of hormone production due to blockage of arterial supply in the pituitary gland is known as:

    <p>Panhypopituitarism</p> Signup and view all the answers

    Which of the following hormones released from the posterior pituitary constricts arterioles and raises blood pressure?

    <p>Vasopressin</p> Signup and view all the answers

    What is the anatomical location of the pituitary gland?

    <p>Below the hypothalamus in the sella turcica</p> Signup and view all the answers

    Study Notes

    Pituitary Gland

    • Located in the hypophyseal fossa (sella turcica) beneath the hypothalamus, connected by the infundibulum.
    • Covered by the diaphragma sella, a fold of dura mater.
    • Related anatomically to the cavernous sinus and optic chiasma.

    Pituitary Gland Lobes

    • Anterior Lobe: Comprises pars distalis, pars tuberalis, and pars intermedia.
    • Posterior Lobe: Includes pars nervosa, infundibular stalk, and median eminence.

    Blood Supply and Connections

    • Supplied by superior and inferior hypophyseal arteries, branches of the internal carotid artery.
    • Posterior lobe receives nerve fibers from the supraoptic and paraventricular nuclei (hypothalamo-hypophyseal tract).
    • Anterior lobe links to the hypothalamus via the hypothalamo-hypophyseal portal system.

    Histology of the Pituitary Gland

    • Fibro-elastic capsule covers the gland; trabeculae carry blood vessels into pars distalis.
    • Pars Distalis: Contains chromophobes and chromophil cells; acidophils and basophils are present.
    • Pars Tuberalis: Features cuboidal cells with central nuclei.
    • Pars Intermedia: Secretes melanocyte-stimulating hormone (MSH).

    Posterior Pituitary

    • Characterized by non-myelinated axons and Herring bodies (expanded terminal ends).
    • Contains pituicytes, neuroglial cells with branching processes and granules.

    Hormones and Their Effects

    • Anterior Pituitary:

      • Growth hormone: Overall growth promotion.
      • Follicle Stimulating Hormone (FSH): Promotes ovarian follicles and sperm production.
      • Luteinizing Hormone (LH): Stimulates ovulation and testicular interstitial cells.
      • Thyroid Stimulating Hormone (TSH): Acts on the thyroid gland.
      • Adrenocorticotropic Hormone (ACTH): Targets the adrenal cortex.

    • Posterior Pituitary:

      • Antidiuretic hormone (vasopressin): Constricts arterioles and raises blood pressure.
      • Oxytocin: Acts on uterine muscle and mammary gland ducts.

    Disorders of the Pituitary Gland

    • Adenoma: Excessive hormone production leading to conditions like Cushing's disease and gigantism.
    • Panhypopituitarism: Rare failure of hormone production due to blockage of arterial supply.

    Adrenal Glands

    • Paired, yellowish glands located retroperitoneally on the kidneys' upper poles.
    • Right adrenal gland: Pyramidal shape; related to the liver and inferior vena cava.
    • Left adrenal gland: Crescentic shape; associated with the pancreas and stomach.

    Adrenal Gland Blood Supply

    • Supplied by superior suprarenal (from inferior phrenic artery), middle suprarenal (from aorta), and inferior suprarenal arteries (from renal artery).
    • Venous drainage via suprarenal veins: right vein drains into the inferior vena cava, left vein drains into the renal vein.

    Histology of Adrenal Gland

    • Adrenal cortex: Has three zones (glomerulosa, fasciculata, reticularis) producing various hormones.
    • Adrenal medulla: Contains chromaffin cells that secrete adrenaline and noradrenaline.

    Adrenal Gland Disorders

    • Hypoadrenalism: Results in Addison's disease, marked by weakness and low sodium.
    • Hyperadrenalism: Can lead to Cushing's syndrome and Conn's syndrome, often due to tumors.

    Pineal Gland

    • Small, spherical gland located inferior to the posterior corpus callosum.
    • Synthesizes melatonin in response to darkness.

    Histology of the Pineal Gland

    • Composed of pinealocytes (modified neurons) and neuroglial cells.
    • Contains calcium and magnesium phosphate, with age-related basophilic bodies (pineal sand).

    Pancreas

    • Functions as both exocrine and endocrine gland; lies posterior to the peritoneum.
    • Supplied by splenic artery and superior/inferior pancreaticoduodenal arteries.

    Histology of the Pancreas

    • Exocrine secretory acini and Islets of Langerhans scattered throughout the exocrine tissue.
    • Alpha cells produce glucagon, beta cells produce insulin, and delta cells produce gastrin.

    Thymus

    • Largest during puberty, gradually replaced by fatty tissue afterward.
    • Produces hormones regulating immune cell production, crucial for T cell maturation.

    Histology of the Thymus

    • Composed of a cortex (basophilic) containing T lymphocytes and a medulla with Hassall's corpuscles.
    • Supports framework provided by epithelial cells, with a loose collagenous capsule.

    Testes

    • Encapsulated in dense fibrous tissue (tunica albuginea), divided into lobules containing seminiferous tubules.
    • Leydig cells produce testosterone.

    Disorders of the Testes

    • Testicular cancer, varicocele, and hydrocele testis are common disorders.

    Ovaries

    • Located in the pelvic region, encapsulated by tunica albuginea.
    • Comprises germinal epithelium, cortex, and medulla with various hormone-producing structures.

    Ovarian Disorders

    • Includes ovarian cysts, polycystic ovary syndrome, ovarian cancer, and changes seen in menopause.

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    Description

    Explore the intricate details of the pituitary gland, its location, and its relations to surrounding structures. This quiz covers the anatomy, lobes, and important connections of the pituitary gland, including its role in hormonal regulation.

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