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ENDOCRINE SYSTEM, Pancreas - Coggle Diagram

- - - - Three major classes of molecules function as hormones in vertebrates:
        
        Polypeptides (proteins and peptides)
        
        Polypeptides and amines are water-soluble.
        
        – Amines derived from amino acids
        
        – Steroid hormones
        
        Steroids are lipid-soluble.
  - - - For example, tear ducts, salivary glands,
        sweat glands.
    - - Pancreas
      - Gonads
- - - - Oxytocin
        
        Oxytocin induces uterine contractions and the release of milk. Suckling sends a message to the hypothalamus via the nervous system to release oxytocin, which further
        stimulates the milk glands.
        
        This is an example of positive feedback, where the stimulus leads to an even greater response.
      - Antidiuretic Hormone or Vazopressin (ADH)
        
        ADH enhances water reabsorption from collecting ducts in kidneys resulting less water in urine.
        
        Balance osmotic pressure of blood.
        
        Secretion of ADH is controlled by a negative feedback mechanism as follows;
        
        Less water in blood → hypothalamus → ADH → kidney → reabsorbs water makes blood
        more dilute / makes urine more concentrated
    - - Tropic Hormones
        
        FSH (Follicle-stimulating hormone)
        
        Stimulate follicle growth and estrogen hormone production during menstrual cycle in
        females.
        
        LH (Follicle-stimulating hormone)
        
        Stimulate ovulation and corpus luteum formation.
        
        Control production of estrogen and progesterone hormones from corpus luteum in
        females.
        
        Stimulates testosterone hormone production in testes in males.
        
        Both FSH and LH are also called gonadotropins.
        
        1 more item...
        
        TSH (Thyroid-stimulating hormone)
        
        Controls secretion of hormones from thyroid gland.
        
        Excess TSH stimulate thyroid glands more, and more hormone produced in thyroid
        glands which eventually cause increase in tyroid gland cells and thyroid gland enlargement.
        
        ACTH (Luteinizing hormone)
        
        Controls secretion of steroid hormones from cortex region of adrenal glands.
      - Nontropic Hormones
        
        Prolactin
        
        stimulates lactation, growth of mammary glands and production of milk. It also
        plays a role in carbohydrate and fat metabolism.
        
        MSH (Melanocyte-stimulating hormone)
        
        Influences skin pigmentation in some vertebrates and fat metabolism in mammals.
      - Tropic and Nontropic Effects
        
        GH (Growth Hormone)
        
        It is made up of 200 amino acids.
        
        It promotes growth directly and
        has diverse metabolic effects.
        
        It stimulates muscles, bones and
        cartilage grow.
        
        GH promotes fat metabolism
        rather than glucose metabolism.
  - - - The main hormone of thyroid gland is the iodine-containing hormone called thyroxine.
      - Thyroxine hormone stimulate metabolism and influence development and maturation.
        
        Increase protein synthesis during growth and develeopment
        
        Increase blood pressure and heart beat rate and metabolic rate
        
        There is no one target organ, all organs respond.
    - - The second hormone released from thyroid gland is calcitonin.
      - Calcitonin decreases the Ca2+ level of blood
        
        It stimulates Ca2+ deposition in bones and decreases reabsorbtion of Ca2+ in
        kidneys and increases excretion of Ca2+ by urine.
        
        Works antagonistacally with parathyroid hormone to balance calcium (Ca2+) in the blood of
        mammals
  - - - Adrenal Cortex Hormone
        
        The adrenal cortex releases a family of steroids called corticosteroids in response to stress.
        
        corticosteroids
        
        Mineralocorticoids
        
        1)Aldosterone, affect salt and water balance in blood.
        
        2) Acts on the tubules of the kidney to stimulate reabsorption of sodium and water into the blood and excrete potassium.
        
        3) Low levels of aldosterone results in Addison disease characterized by low blood pressure, bronzing of skin and open to infections.
        
        Androgens
        
        The adrenal cortex also produces small amounts of steroid sex hormones; estrogen, progesterone and testosterone. Women may have masculinization from oversecretion of adrenal male sex hormone.
        
        Glucocorticoids
        
        1) Cortisol, influence glucose metabolism and the immune system.
        
        2) It stimulates the production of glucose from fats and amino acids and reduce inflammation.
        
        3) High levels of cortisol results in Cushing Syndrome.
        
        ACTH released from anterior pituitary control the adrenal cortex hormones secretion.
      - Adrenal Medulla Hormone
        
        They are secreted in response to stress-activated impulses from the nervous system.
        
        The adrenal medulla secretes epinephrine (adrenaline) and norepinephrine (noradrenaline).
        
        Effects Of:
        
        1) Glycogen broken down to glucose; increased blood glucose.
        
        2) Increased blood pressure
        
        3) Increased breathing rate
        
        4) Increased metabolic rate
        
        5) change in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity.
        
        The release of epinephrine and norepinephrine occurs in response to nerve signals from the hypothalamus.
        Norepinephrine is released as neurotransmitter from neurons.
  - - - stimulates development and maintenance of the male reproductive system
      - Stimulates development of male secondary sex characteristics: large vocal cords, pubic hair, etc.
    - - Estrogen
        
        Estrogen is released from follicle and responsible for maintenance of the female reproductive system.
        
        Secreted at puberty stimulate maturation of ovaries and other sexual organs.
        
        Necessary for oocyte (egg) development.
      - Progesterone
        
        Progesterone, are primarily involved in preparing and maintaining the uterus.
      - Synthesis of female sex hormones is controlled
        by FSH and LH from the anterior pituitary.
        
        Feedback mechanism
- - - - The pineal gland, located in the brain, secretes melatonin, primarily at night.
      - Light/dark cycles control release of melatonin.
      - Melatonin may cause seasonal affective disorder where persons are depressed at onset of winter.
    - - It is a contributor to feelings of well-being and happiness. The activity of serotonergic neurons is slowest or absent during sleep and highest during states of alert wakefulness. Serotonin may also be important in the neural pathways controlling mood.
  - - - Work antagonistically with calcitonin hormone secreted from thyroid gland.
      - Malfunctions of Parathormone
        
        Tetany
        
        Low Ca+2 level increase excitability of nerve without rest and this results in continuous muscle contraction. It causes painful muscle contraction. If larynx muscles affected by this condition, results in death.
        
        Bones become weak and brittle.
        
        cause kidney stones
- - - - Daily insulin injections are needed to correct the carbohydrate imbalance that results.