The Endocrine System by HC11112303720

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									               The Endocrine System

• Controls many body            • Derives its name from
  functions                       the fact that various
   – exerts control by            glands release
     releasing special            hormones directly into
     chemical substances into     the blood, which in turn
     the blood called
     hormones
                                  transports the
   – Hormones affect other
                                  hormones to target
     endocrine glands or body     tissues via ducts.
     systems
           The Endocrine System

• Exocrine glands -    • Endocrine
  transport their        Emergencies:
  hormones to target     – from common:
  tissues via ducts.         • Diabetes
                             • to the unusual:
                                 – Thyrotoxicosis
           The Endocrine System
                         • Pituitary gland: a small
                           gland located on a stalk
• Consists of several      hanging from the base of the
                           brain - AKA
  glands located in
  various parts of the   • “The Master Gland”
  body.
                            – Primary function is to
                              control other glands.
                            – Produces many
                              hormones.
                            – Secretion is controlled by
                              the hypothalamus in the
                              base of the brain.
           The Endocrine System
                           • The two segments are:
• The Pituitary Gland is      – Posterior Pituitary:
  divided into 2 areas,           • produces oxytocin
  which differ                      and antidiuretic
                                    hormone (ADH)
   – structurally and
                              – Anterior Pituitary:
     functionally
                                  • produces thyroid-
   – each area has                  stimulating hormone
     separate types of              (TSH)
     hormone production.          • growth hormone (GH)
                                  • adrenocorticotropin
                                    (ACTH)
                                  • follicle-stimulating
                                    hormone (FSH)
           The Endocrine System

• And even more…          • Posterior Pituitary
  – luteinizing hormone      – Oxytocin (the
    (LH)                       natural form of
                               pitocin)
  – prolactin
                                • stimulates gravid
                                   uterus
• Let’s go over these           • causes “let down”
                                   of milk from the
  one at a time...                 breast.
                             – ADH (vasopressin)
                               causes the kidney to
                               retain water.
            The Endocrine System
• Anterior Pituitary       • Anterior Pituitary…
   – Primarily regulates      – Growth hormone
     other endocrine            (GH)
     glands
                                 •  glucose usage
   – rarely a factor in
                                 •  consumption of
     endocrinological              fats as an energy
     emergencies
                                   source
   – TSH stimulates the
                              – ACTH stimulates the
     thyroid gland to           adrenal cortex to
     release its                release its hormones
     hormones, thus 
     metabolic rate           – FSH & LH stimulates
                                maturation & release
                                of eggs from ovary.
           The Endocrine System
• The Thyroid Gland         • Within the colloid are
                              the thyroid hormones:
  – lies in the anterior
    neck just below the        – thyroxine (T4)
    larynyx.                   – triiodothyronine (T3)
  – Two lobes, located             • When stimulated
    on either side of the            (by TSH or by
    trachea, connected               cold), these are
    by a narrow band of              released into the
    tissue called the                circulatory system
    isthmus.                         and  the
  – Sacs inside the                  metabolic rate.
    gland contain colloid      – “C” cells within the
                                 thyroid produce the
                                 hormone calcitonin.
          The Endocrine System

• Calcitonin, when       • Myxedema symptoms:
  released, lowers the     – Facial bloating
  amount of calcium in     – weakness
  the blood.               – cold intolerance
• Inadequate levels of     – lethargy
  thyroid hormones =       – altered mental
  hypothyroidism, or         status
  Myxedema.                – oily skin and hair
                           – TX: replacement of
                             thyroid hormone.
            The Endocrine System
• Increased thyroid         – Long term
  hormone release             hyperthyroidism:
  causes                       • Exopthalmos
  hyperthyroidism,                 – bulging of the
  commonly called                    eyeballs (picture
  Graves’ disease.                   Barbara Bush)
   – Signs and                 • In severe cases - a
     symptoms:                   medical emergency
      • insomnia, fatigue        called thyrotoxicosis
      • tachycardia              can result.
      • hypertension
      • heat intolerance
      • weight loss
           The Endocrine System

• Parathyroid Glands         – produce parathyroid
  – small, pea-shaped          hormone -  level of
    glands, located in the     calcium in blood
    neck near the thyroid
  – usually 4 - number can   – Hypocalcemia can
    vary                       result if parathyroids
  – regulate the level of      are removed or
    calcium in the body        destroyed.
         The Endocrine System
• Pancreas                   • Islets of Langerhans
  – a key gland located in      – specialized tissues in
    the folds of the              which the endocrine
    duodenum                      functions of the
  – has both endocrine and        pancreas occurs
    exocrine functions          – include 3 types of
  – secretes several key          cells:
    digestive enzymes              • alpha ( )
                                   • beta ()
                                   • delta ()
                                – each secretes an
                                  important hormone.
            The Endocrine System

• Alpha () cells           • The surge of glucagon
  release glucagon,           stimulates the liver to
  essential for               release glucose stores
  controlling blood           (from glycogen and
  glucose levels.             additional storage
• When blood glucose          sites).
  levels fall,  cells     • Also, glucagon
  the amount of               stimulates the liver to
  glucagon in the blood .     manufacture glucose -
                            • gluconeogenesis.
         The Endocrine System
• Beta Cells () release     • Insulin is rapidly
  insulin (antagonistic to     broken down by the
  glucagon).                   liver and must be
• Insulin  the rate at        secreted constantly.
  which various body         • Delta Cells ()
  cells take up glucose.       produce somatostatin,
  Thus, insulin lowers         which inhibits both
  the blood glucose            glucagon and insulin.
  level.
            The Endocrine System

• Adrenal Glands              • the Adrenal Medulla
  – 2 small glands that sit     secretes the
    atop both kidneys.          catecholamine
                                hormones
  – Each has 2 divisions,       norepinephrine and
    each with different         epinephrine (closely
    functions.                  related to the
                                sympathetic
                                component of the
                                autonomic nervous
                                system).
            The Endocrine System
                           • One at a time…
• The Adrenal Cortex         – gluticocorticoids:
  secretes 3 classes of      – accounts for 95% of
  hormones, all steroid        adrenal cortex
  hormones:                    hormone production
   – gluticocorticoids       –  the level of glucose
     mineralocorticoids        in the blood
   – androgenic hormones     – Released in response to
                               stress, injury, or
                               serious infection - like
                               the hormones from the
                               adrenal medulla.
            The Endocrine System

• Mineralocorticoids:       • Signs & Symptoms of
   – work to regulate the     Cushing’s Disease:
     concentration of         –  in blood sugar levels
     potassium and sodium     – unusual body fat
     in the body.               distribution
• Prolonged  in             – rapid mood swings
  adrenal cortex
  hormone results in
  Cushing’s Disease.
             The Endocrine System

• And - if there is an       • Sodium can also be
  in mineralocorticoids         retained by the kidney,
  as well                       resulting in
                                hyponatremia.
   – A serious electolyte
     imbalance will occur        – Causes:
     due to the  potassium         • dysrhythmias
     excretion by the               • coma
     kidney, which results          • death
     in hypokalemia.             – usually results from a
                                   tumor - TX? Removal
                                   of tumor.
            The Endocrine System

• Gonads and Ovaries:        • Ovaries:
   – the endocrine glands      – located in the
     associated with human       abdominal cavity
     reproduction.               adjacent to the uterus.
   – Female ovaries            – Under the control of
     produce eggs                LH and FSH from the
   – Male gonads produce         anterior pituitary they
     sperm                       manufacture
                                  • estrogen
• both have endocrine             • protesterone
  functions.
            The Endocrine System

• Estrogen and              • Testes:
  Progesterone have            – located in the scrotum
  several functions,           – produce sperm for
  including sexual               reproduction
  development and              – manufacture
  preparation of the             testosterone -
  uterus for implantation         • promotes male growth
                                    and masculinization
  of the egg.
                               – Controlled by anterior
                                 pituitary hormones
                                 FSH and LH.
             The Endocrine System

• Endocrine                    • Complications of
  Emergencies:                   Diabetes:
• Diabetes Mellitus              – contributes to heart
   – one of the most               disease
     common diseases in          – stroke
     North America.              – kidney disease
   –  insulin secretion by     – blindness
     the Beta () cells of
     the islets of
     Langerhans in the
     pancreas.
            The Endocrine System

• Pathophysiology of          • The other 2 major
  Diabetes:                     food sources are
• Glucose Metabolism             – proteins
  – Glucose (dextrose) is a      – fats
    simple sugar required     • Most sugars in the
    by the body to produce      human diet are
    energy.
                                complex and must be
  – Sugars, or
                                broken down into
    carbohydrates, are 1 of
    3 major food sources        simple sugars:
    used by the body.           glucose, galactose and
                                fructose - before use.
             The Endocrine System

• Breakdown of sugars          • To be converted into
  is carried out by              energy, glucose must
  enzymes in the gastro          first be transmitted
  intestinal system.             through the cell
   – As simple sugars, these     membrane. BUT - the
     are absorbed from the       glucose molecule is
     GE system into the          large and doesn’t
     body.
                                 readily diffuse through
   – More than 95% enter         the cell membrane.
     the body as glucose.
             The Endocrine System

• Glucose must pass            • The rate at which
  into the cell by               glucose can enter the
  binding to a special           cell is dependent upon
  carrier protein on the         insulin levels.
  cell’s surface.                 – Insulin serves as the
   – Facilitated diffusion -        messenger - travels via
     doesn’t use energy.            blood to target tissues.
     The carrier protein          – Combines with specific
     binds with the glucose         insulin receptors on the
     and carries it into the        surface of the cell
     cell.                          membrane.

								
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