Endocrine System Anatomy Quiz
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Questions and Answers

What are the Herring bodies primarily known for?

  • Transporting hormones to the bloodstream
  • Storing neurosecretory material (correct)
  • Maintaining osmotic balance
  • Connecting the pituitary gland to the hypothalamus

    • Pituicytes are endocrine cells that release hormones into the bloodstream.

    False

    What hormones are associated with the neurosecretory bodies in the neurohypophysis?

    Oxytocin and ADH

    The axons from the supraoptic and __________ nuclei are mainly concerned with oxytocin secretion.

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

    What triggers the release of ADH from the neurosecretory bodies?

    <p>Increased blood tonicity</p> Signup and view all the answers

    Match the following components of the pituitary gland with their functions:

    <p>ADH = Increases water reabsorption in renal collecting ducts Pituicytes = Support neurosecretory fibers Herring bodies = Store neurosecretory material Inferior hypophyseal arteries = Supply blood to the neurohypophysis</p> Signup and view all the answers

    The blood supply of the pituitary gland comes entirely from the internal jugular vein.

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

    What is the primary role of the superior hypophyseal arteries?

    <p>Supply the median eminence and the infundibular stalk</p> Signup and view all the answers

    Which gland is NOT part of the endocrine system?

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

    The endocrine system includes both ductless glands and isolated cells within certain organs.

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

    What do hormone-producing cells in the adrenal cortex synthesize?

    <p>Steroid hormones</p> Signup and view all the answers

    The ______ is a ductless gland located at the base of the skull.

    <p>pituitary gland</p> Signup and view all the answers

    Match the following components of the pituitary gland with their descriptions:

    <p>Pars Distalis = Main hormone-producing area of the anterior lobe Pars Tuberalis = Wraps around the infundibulum stalk Pars Intermedia = Thin zone adjacent to pars nervosa Pars Nervosa = Part of the posterior lobe of the pituitary</p> Signup and view all the answers

    What type of hormones are synthesized by rough endoplasmic reticulum?

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

    Amine hormones are synthesized from cholesterol.

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

    What is the primary function of the endocrine system?

    <p>Regulate body functions through hormones</p> Signup and view all the answers

    What is the primary role of the hypothalamic-hypophyseal portal system?

    <p>To carry neuropeptides from the hypothalamus to the adenohypophysis</p> Signup and view all the answers

    Antidiuretic hormone (ADH) is synthesized in the paraventricular nuclei.

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

    What are the two peptide hormones synthesized by hypothalamic neurons mentioned?

    <p>Antidiuretic hormone (ADH) and oxytocin</p> Signup and view all the answers

    The pineal gland is also known as the ______.

    <p>epiphysis cerebri</p> Signup and view all the answers

    Which cells produce growth hormone?

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

    Match the following hormones with their hypothalamic nuclei:

    <p>Antidiuretic hormone (ADH) = Supraoptic nucleus Oxytocin = Paraventricular nucleus</p> Signup and view all the answers

    All hypothalamic hormones that affect the anterior pituitary are releasing hormones.

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

    What shape is the pineal gland?

    <p>Pine cone-shaped</p> Signup and view all the answers

    What type of cells are primarily found in the pars intermedia?

    <p>Basophils and chromophobes</p> Signup and view all the answers

    The pars distalis accounts for 50% of the mass of the pituitary gland.

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

    What is the primary function of melanocyte-stimulating hormone (MSH)?

    <p>Increases melanocyte activity</p> Signup and view all the answers

    The neurohypophysis is also known as the ______.

    <p>pars nervosa</p> Signup and view all the answers

    Match the following types of cells with their corresponding hormones:

    <p>Somatotrophs = Growth Hormone (GH) Thyrotrophs = Thyroid Stimulating Hormone (TSH) Gonadotrophs = Follicle Stimulating Hormone (FSH) Corticotrophs = Adrenocorticotrophic Hormone (ACTH)</p> Signup and view all the answers

    What is the primary function of the pineal gland?

    <p>Producing melatonin</p> Signup and view all the answers

    Which component consists of the unmyelinated axons from magnocellular neurosecretory cells?

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

    Chromophobes take up histological stains.

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

    The presence of corpora arenacea has a significant effect on the function of the pineal gland.

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

    What links the pituitary gland to the hypothalamus?

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

    What type of nerve fibers enter the pineal gland and form synapses with pinealocytes?

    <p>Unmyelinated sympathetic nerve fibers</p> Signup and view all the answers

    Melatonin release is promoted by __________ and inhibited by __________.

    <p>darkness, daylight</p> Signup and view all the answers

    Match the components with their functions related to the pineal gland:

    <p>Pinealocytes = Produce melatonin Corporeal arenacea = Calcium and magnesium concretions Sympathetic nerve fibers = Regulate melatonin secretion Glial cells = Support and protect nerve cells</p> Signup and view all the answers

    Which group of cells within the pineal gland has a characteristic basophilic cytoplasm?

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

    The cycle of light and darkness is detected within the retinas and transmitted to the pineal gland.

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

    What is the effect of darkness on blood melatonin levels?

    <p>Promotes an increase</p> Signup and view all the answers

    Study Notes

    Endocrine System Overview

    • The endocrine system is one of two major control systems regulating body functions, the other being the nervous system.
    • It synthesizes and secretes hormones in small amounts, distributed via the bloodstream to target organs.
    • Hormones act slowly (minutes to days) and at low concentrations.

    Endocrine System Components

    • The endocrine system includes ductless glands (e.g., pituitary, thyroid, parathyroid, adrenal, and pineal).
    • Isolated cells within organs like the islets of Langerhans, gonads, placenta, thymus, and kidneys also contribute.
    • Diffuse neuro-endocrine system cells (DNES-C) are also part of the system.

    Histological Features of Endocrine Glands/Cells

    • Endocrine glands lack ducts, directly secreting hormones into the bloodstream.
    • Parenchymal cells are organized into columns, glomeruli, follicles, or groups, with at least one cell surface facing a blood capillary.
    • Glands are richly supplied with fenestrated blood capillaries.

    Hormone Producing Cell Types

    • Different hormone types (peptides, amines, steroids) yield different microscopic appearances in hormone-producing cells.
      • Peptides/glycopeptides are synthesized in the rough endoplasmic reticulum and stored in secretory vesicles (e.g., cells of the pituitary gland).
      • Amines are amino acid derivatives like thyroid hormone, epinephrine, and norepinephrine, synthesized and stored in a manner similar to peptide hormones.
      • Steroids are synthesized on demand from cholesterol via enzymes in the mitochondria and smooth ER (e.g., adrenal cortex cells).

    Pituitary Gland (Hypophysis Cerebri)

    • Located in the sella turcica of the skull base.
    • Separated into anterior and posterior lobes by a cleft.

    Anterior Lobe (Adenohypophysis)

    • Consists of:
      • Pars distalis (75% of mass), arranged in branching cords separated by fenestrated capillaries.
      • Pars tuberalis, wrapping around infundibulum.
      • Pars intermedia, between pars distalis and pars nervosa (contains basophils and colloid cysts).
    • Cells are chromophils (acidophils, basophils) or chromophobes based on staining affinity.
      • Acidophils (37%): Somatotrophs (growth hormone), Lactotrophs (prolactin).
      • Basophils (11%): Thyrotrophs (thyroid-stimulating hormone), Gonadotrophs (follicle-stimulating and luteinizing hormones), Corticotrophs (adrenocorticotropic hormone).
      • Chromophobes (52%): Have no readily apparent granules.
    • Pars intermedia synthesizes a large M.W polypeptide to produce mainly smaller peptide hormones including MSH.

    Posterior Lobe (Neurohypophysis)

    • Composed of:
      • Pars nervosa, composed of fibers, cells and rich capillary plexus originating from unmyelinated neurons from supraoptic and paraventricular nuclei of hypothalamus.
      • Infundibulum stalk connecting to hypothalamus.
      • Herring bodies, faintly basophilic, small bodies where neurosecretions are stored.
      • Pituicytes are neuroglial cells in pars nervosa.

    Pineal Gland

    • Located in the epithalamus, posterior wall of third ventricle.
    • Pine cone-shaped structure, 5-8mm by 3-5mm.
    • Covered with connective tissue, creating lobules, containing many pinealocytes and blood vessels.
    • Contains corpora arenacea (brain sand) comprised of calcium and magnesium salts.
    • Pinealocytes are secretory cells, have numerous mitochondria and secretory vesicles, and produce melatonin.
    • Unmyelinated sympathetic nerve fibers enter the gland to end near the pinealocytes.
    • Interstitial glial cells (modified astrocytes) are prominent and their distribution & activity is linked to their presence.

    Pituitary Gland Blood Supply

    • Derived from superior/inferior hypophyseal arteries, branching into primary/secondary capillary plexuses.
    • Secondary capillary plexus is in adenohypophysis, providing blood to anterior pituitary.
    • Superior hypophyseal arteries supply median eminence and infundibular stalk, providing blood to the neurohypophysis.

    Hypothalamic-Hypophyseal Portal System

    • Carries regulatory peptides from the hypothalamus to the anterior pituitary, stimulating/inhibiting hormone release.

    Hormone Secretion Control

    • Anterior pituitary cell activities regulated by hypothalamic hormones (releasing/inhibiting) carried by the portal system.

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    Endocrine System -I For Medical Students PDF

    Description

    Test your knowledge on the anatomy and functions of the endocrine system, focusing on the pituitary gland and hormone secretion. This quiz covers key concepts like Herring bodies, neurosecretory bodies, and their roles in hormonal regulation.

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