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Endocrine System - Coggle Diagram

- - - - Flattened funnel shape that forms floor/walls of 3rd ventricle of brain
    - - Thermoregulation
      - Hunger
      - Parenting/Attachment behaviors
      - Thirst/Water balance
      - Fatigue/Sleep
      - Circadian Rhythms
      - Sex Drive
      - Childbirth
    - - is a stalk that suspends the
    - - TRH
        
        Thyrotropin-Releasing Hormone
        
        promotes secretion of TSH and PRL
      - CRH
        
        Corticotropic-Releasing Hormone
        
        promotes secretion of ACTH
      - GnRH
        
        Gonadotropin-Releasing Hormone
        
        promotes secretion of FSH and LH
      - GHRH
        
        Growth Hormone-Releasing Hormone
        
        promotes secretion of GH
      - PIH
        
        Prolactin-Inhibiting Hormone
        
        inhibits secretion of PRL
      - Somatostatin
        
        inhibits secretion of GH and TSH
      - 4 releasing + 2 inhibitory
  - - - Attached to roof of third ventricle beneath posterior end of corpus callosum
    - - involution (shrinkage)
        
        By end of puberty it is down
        
        75%
        
        Pineal Gland may influence timing of puberty
    - - Melatonin
        
        synthesized from
        
        Seratonin
        
        secretion peaks at
        
        3-5 hours after onset of sleep
        
        link with mood disorders such as
        
        PMS (Premenstrual Syndrome)
        
        both can be relived by
        
        Phototherapy (3 hours of exposure to bright light daily)
        
        reduces melatonin levels
        
        SAD (Seasonal Affective Disorder)
  - - - Size/Shape of Kidney Bean housed in sella turcica of sphenoid bone
    - - Hormones
        
        FSH
        
        Follicle-Stimulating Hormone
        
        goes to the:
        
        Testes
        
        stimulates sperm production
        
        Ovaries
        
        development of bubble-like follicles that contain the eggs
        
        stimulates secretion of ovarian sex hormones
        
        Gonadotropins
        
        target gonads
        
        secreted by gonadotropic cells
        
        LH
        
        Luteinizing Hormone
        
        goes to the:
        
        Ovaries
        
        stimulates Corpus Luteum (the follicle becomes
        a yellow body after ovulation called the CL, where hormone gets its name) to secrete
        
        1 more item...
        
        stimulates Ovulation (release of an egg)
        
        Testes
        
        stimulates testes to produce Testosterone
        
        TSH
        
        Thyroid-Stimulating Hormone / Thryotropin
        
        secreted by:
        
        Thyrotropic cells
        
        goes to the:
        
        Thyroid Gland
        
        stimulates growth of Thyroid Gland
        
        stimulates secretion of:
        
        1 more item...
        
        ACTH
        
        Adrenocorticotropic Hormone / Corticotropin
        
        secreted by:
        
        Corticotropic cells
        
        goes to the:
        
        Adrenal Cortex
        
        stimulates it to secrete
        
        1 more item...
        
        PRL
        
        Prolactin
        
        secreted by:
        
        Prolactin cells
        
        After birth:
        
        goes to the:
        
        Mammary Glands
        
        1 more item...
        
        Pregnancy:
        
        as
        
        lactotropes
        
        1 more item...
        
        GH
        
        Growth Hormone / Somatotropic
        
        secreted by
        
        Somatotropic cells
        
        most numerous cells in anterior pituitary
        
        1 more item...
        
        goes to the:
        
        Bone, Cartilage, Muscle, Fat
        
        stimulates
        
        1 more item...
        
        Liver
        
        produces growth stimulants
        
        2 more items...
        
        in adolescence:
        
        6 ng/ml
        
        in old age:
        
        1 more item...
      - release of hormones controlled by:
        
        Brain monitoring conditions
        
        During pregnancy, hypothalamus triggers ACTH secretion
    - - Hormones
        
        ADH
        
        Antidiuretic Hormone
        
        goes to the:
        
        Kidneys
        
        increases water retention
        
        2 more items...
        
        can also function as brain neurotransmitter called
        
        Arginine Vasopressin
        
        with an ability to cause vasoconstriction - but requires unnaturally high concentrations in our body
        
        OT
        
        Oxytocin
        
        goes to the:
        
        Reproductive Organs
        
        propulsion of semen (M)
        
        Uterine contractions to help transport sperm (F)
        
        stimulates Labor contractions (F)
        
        Mammary Glands
        
        stimulates flow of milk from mammary gland out to infant
        
        feelings of emotional bonding / sexual satisfaction
        
        emotional bonding between mother and infant
      - release of hormones controlled by:
        
        Neuroendocrine Reflexes
        
        Infant suckling triggers hypothalamic response to release oxytocin
  - - - 25 grams
    - - adjacent to Trachea, below Larynx
    - - Isthmus
    - - Thyroid Follicles
        
        made up of follicular cells that secrete
        
        80 micrograms of Thyroid hormone daily (90% T4, 10% T3)
        
        at the periphery of the follicles are
        
        Parafollicular Cells / Clear (C) cells
        
        secrete Calcitonin
        
        10x as many in children than adults
    - - Thyroid Hormone
        
        T4
        
        Tetraiodothyronine / Thryoxine
        
        T3
        
        Triiodothyronine
        
        4 and 3 refer to
        
        number of Iodine atoms in each structure
        
        Functions, Increases:
        
        increases metabolic rate, O2 consumption
        
        heat production (calorigenic effect)
        
        Appetite
        
        GH secretion
        
        Alertness
        
        Reflex speed
      - Calcitonin
        
        responds to rising levels of blood calcium by
        
        antagonizing Parathyroid to stimulate osteoblast activity
        
        promoting calcium deposition and bone formation
  - - - Endocrine
      - Lymphatic
      - Immune
    - - Bilobed gland in mediastinum superior to heart behind sternal manubrium
    - - huge compared to organs next to it
        
        grows until age 5/6
        
        involuation happens
        
        after puberty
    - - Thymopoietin
        
        stimulate development of other lymphatic organs and activity of T lymphocytes
      - Thymosin
      - Thymulin
  - - - dual nature acting as both
        
        endocrine gland
        
        sympathetic nervous system ganglion
      - innervated by:
        
        sympathetic preganglionic fibers
        
        the modified sympathetic postganglionic neurons are called:
        
        Chromaffin Cells
        
        Hormones:
        
        Catecholamines
        
        4 more items...
        
        some extend into cortex and stimulate when stress activates Sympathetic Nervous System
      - inner core, 10-20% of the gland
    - - Zona Reticularis
        
        narrow, inner layer
        
        cells in branching network
        
        secretes
        
        Sex steroids
        
        primary adrenal sex steroids are the:
        
        Androgens
        
        major androgen is:
        
        1 more item...
        
        main adrenal estrogen is:
        
        1 more item...
        
        also regulated by ACTH
      - Zona Fasciculata
        
        thick, middle layer
        
        cells arranged in fascicles seperated by capillaries
        
        secretes
        
        Glucocorticoids
        
        in response to
        
        ACTH
        
        (from stress)
        
        strongest
        
        Cortisol
        
        regulates metabolism of glucose and other fuels by
        
        1 more item...
        
        Medulla atrophies without stimulation of cortisol
        
        weaker
        
        Corticosterone
      - Zona Glomerulosa
        
        thin, outer layer
        
        cells arranged in rounded clusters
        
        secretes
        
        Mineralocorticoids
        
        steroid hormones that regulate body's electrolyte balance
        
        most significant:
        
        Aldosterone
        
        stimulates Na+ retention and K+ excretion
        
        part of the
        
        1 more item...
      - 3 layers of glandular tissue surrounding the Medulla
    - - on top of the kidneys
  - - - elongated, spongy gland, below and behind stomach
    - - scattered throughout the endocrine tissue, there are 1-2 million exocrine cell clusters called
        
        Pancreatic islets (islets of Langerhans)
        
        2% of Pancreatic tissue | contains from a few to 3,000 cells
        
        main cell types:
        
        20%
        
        Alpha Cells / Glucagon Cells
        
        1 more item...
        
        70%
        
        Beta Cells / Insulin Cells
        
        2 more items...
        
        5%
        
        Delta Cells / Somatostatin Cells
        
        1 more item...
        
        small number
        
        PP Cells
        
        1 more item...
  - - - usually 4 glands partially embedded in posterior surface of Thyroid Gland.
      - Can be found as high as Hyoid bone, as low as Aortic Arch
    - - PTH
        
        Parathyroid Hormone
        
        Intestine
        
        increases Ca2+ absorption from food :
        
        Bones
        
        activates osteoclasts to break down bone and release Calcium and Phosphate into blood
        
        Kidney
        
        promotes activation of vitamin D and increases Calcium reabsorption
  - - - Hormones:
        
        Estradiol
        
        Progesterone
        
        Functions
        
        development of feminine physique + reproductive system
        
        promote adolescent bone growth
        
        regulate menstrual cycle
        
        sustain pregnancy
        
        prepare mammary glands for lactation
        
        Inhibin
        
        Suppresses FSH secretion by means of negative feedback inhibition of Ant. Pit.
      - Eggs
        
        develop in their own individual follicles lined by a wall of
        
        Granulosa Cells
        
        surrounded by a capsule called the
        
        Theca
        
        Theca cells synthesize the androgen
        
        1 more item...
        
        convert Androstenedione into
        
        Estradiol
        
        and lesser amounts of
        
        2 more items...
      - Monthly Ovarian Cycle
        
        in the middle of it, a mature follicle ovulates (ruptures and releases the egg)
        
        remains of the follicle become the
        
        Corpus Luteum
        
        which secretes Progesterone for next ~12 days
    - - Hormones:
        
        Testosterone
        
        come from
        
        Interstitial Endocrine Cells
        
        development of male reproductive system in fetus and adolescence
        
        development of masculine physique in adolescence
        
        sex drive
        
        sustains sperm production
        
        weaker androgens
        
        Estrogens
        
        Inhibin
        
        comes from
        
        Nurse Cells
        
        that form the wall of
        
        by limiting FSH, it regulates rate of Sperm Production
      - consist of minute
        
        Seminiferous Tubules
        
        produce
        
        Sperm
    - - Exocrine products:
        
        whole cells (egg + sperm)
      - Endocrine products:
        
        gonadal hormones (mostly steroids)
- - - - convert a Cholesterol-like steroids into
        
        Cholecalciferol
        
        using UV light from Sun
  - - - Cholecalciferol
        
        into
        
        Calcidiol
    - - Angiotensinogen
        
        precursor of
        
        Angiotensin
        
        (a regulator of blood pressure)
    - - Erythropoietin
        
        stimulates bone marrow to produce RBC
    - - IGF-I
        
        controls action of HGH
    - - promotes intestinal absorption of iron
  - - - Calcidiol
        
        to the active form of Vitamin D
        
        Calcitriol
        
        increases Ca2+ absorption by intestine and inhibits loss in urine
    - - Renin
        
        that converts
        
        Angiotensinogen
        
        to
        
        Angiotensin I
        
        (Angiotensin II created by converting enzyme in lungs)
  - - - decrease blood volume and blood pressure by increasing Na+ and H2O output by kidneys. And oppose action of
  - - - secreted by enteroendocrine cells
      - coordinate digestive motility and glandular secretion
      - Cholecystokinin, Gastrin, Ghrelin, Peptide YY (PYY)
  - - - leptin
        
        slows appetite
  - - - Osteocalcin
        
        increases beta cells
  - - - estrogen, progesterone, etc.
- - - - made from amino acids
        
        Tyrosine
        
        Catecholamines
        
        Epinephrine
        
        Norepinephrine
        
        Dopamine
        
        TH
        
        only process in human body that uses
        
        Iodine
        
        lack of Iodine causes:
        
        1 more item...
        
        Process:
        
        Cells of Thyroid Follicle
        
        absorb
        
        1 more item...
        
        synthesize and release via exocytosis
        
        1 more item...
        
        Tryptophan
        
        Melatonin
    - - created from chains of amino acids
        
        Gene for Hormone
        
        mRNA
        
        Ribosomes translate to
        
        amino acids
        
        peptide
        
        1 more item...
      - Pituitary Glands
      - Hypothalamus
      - Insulin
    - - synthesized from
        
        Cholesterol
        
        Progesterone
        
        Cortisol
        
        Aldosterone
        
        Testosterone
        
        Estradiol
      - Sex Steroids (Gonads)
      - Corticosteroids (Adrenals)
  - - - Melatonin
    - - Ovarian Cycle
    - - Nerve fibers supply some Endocrine glands and elicit release of hormones
        
        SNS -> Adrenal Medulla -> Catecholamines (Epinephrine + Norep.)
        
        Childbirth -> stretch receptors -> Nerve signals -> Hypothalmus -> stimulate release of oxytocin
    - - Hormones from Hypothalamus regulate secretion of Ant. Pit. gland
      - Pituitary hormones stimulate other glands to release
        
        TH
        
        Sex hormones
        
        Cortisol
        
        etc.
    - - blood-borne stimuli
        
        rising blood glucose concentration stimulates insulin
        
        low blood osmolarity stimulates aldosterone
        
        low blood calcium level stimulates parathyroid
    - - released as fast as they are synthesized by diffusion thru cell surface
        
        Stimuli (ex. FSH, ACTH) can increase synthesis
    - - stored in secretory vesicles until needed, then exocytosis
    - - diffuses thru plasma membranes, does not accumulate in gland
      - not stored in endocrine cells but in extracellular spaces enclosed by thryroid follicles
        
        TSH causes secretion
  - - - most are hydrophilic
        
        easily mix with blood plasma
    - - Hydrophobic
        
        bind to transport proteins
        
        (Albumins + Globulins synthesized by the liver)
        
        longer half-life
        
        transport proteins protect from being broken down by enzymes in plasma and liver and from being filtered from blood out by kidneys
        
        TH binds to 3 in plasma:
        
        Albumin
        
        Thyretin
        
        Thyroxine-binding globulin (TGB)
        
        Steroid Hormones bind to
        
        Globulins
        
        Cortisol binds to Transcortin
        
        Aldosterone is 85% unbound, 15% binds to Albumin
        
        short half-life
  - - - Signal Amplification
        
        small stimulus cascades into large metabolic product
      - Target-Cell sensitivity adjusted by changing number of receptors
        
        Up-regulation
        
        increases number of receptors
        
        Down-regulation
        
        reduces number of receptors
        
        happens with long term exposure to high hormone concentrations
    - - cannot penetrate target cell
        
        bind to surface receptors
        
        intrecellular processes thru second messengers
        
        activates G protein
        
        activates adenylate cyclase
        
        produces cAMP
        
        1 more item...
    - - penetrate plasma membrane
        
        bind to internal receptors (usually in nucleus)
        
        take several hours/days to show effect due to lag for protein synthesis
        
        Estrogen binds to nuclear receptors in cells of uterus
        
        activates gene for progesterone receptor
        
        progesterone comes later in menstrual cycle and binds to those receipts stimulating transcription of gene for a nutrient-synthesizing enzyme
        
        TH enters target cell by means of ATP-dependent transport protein
        
        within cell, T4 becomes more potent T3
        
        T3 binds to nuclear receptors and activates gene for Na-K pump
  - - - act together for greater effect
        
        FSH + Testosterone to increase sperm production
    - - one hormone enhances the target organ's response to second later hormone
        
        Estrogen prepares Uterus for action of Progesterone
    - - act against each other
        
        Insulin lowers blood glucose and glycogen raises it
  - - - most hormones taken and degraded by liver and kidney
        
        excreted in bile/urine
    - - rate of hormone removal from blood
- - - - tumors or lesions that destroy an endocrine gland or interfere with its ability to receive signals from another cell
        
        ex. fractured sphenoid bone can sever hypothalamo-hypophysial tract and prevent the transport of oxytocin and ADH to post. pituitary gland
        
        disables water retention ability of kidney, and leads to
        
        Diabetes Insipidus
        
        glucose free urine (insipidus = "without taste (sweet)")
      - Autoimmune diseases where cells are attacked by one's own antibodies or immune cells
        
        can cause
        
        Diabetes Mellitus
        
        most prevalent metabolic disease in the world
        
        can be from hyposecretion/inaction of Insulin
        
        Symptoms
        
        excess urine output (Polyuria)
        
        intense thirst (polydipsia)
        
        hunger (polyphagia)
        
        elevated blood glucose
        
        Type 1 Diabetes Mellitus
        
        5-10% of cases in USA
        
        Insulin always used as treatment
        
        hereditary susceptibility
        
        Type 2 (NIDDM)
        
        90-95% of cases
        
        problem is insulin resistance, failure of target cells to respond to it
        
        Pathogenesis
        
        1 more item...
        
        heredity, age (40+), ethnicity
        
        treated with weight-loss program and exercise
        
        since adipose signals interfere with glucose uptake in most cells
      - congenital absence or underdevelopment of pituitary gland can cause wide-spectrum hyposecretion of many hormones
        
        lifelong hormone replacement therapy
  - - - tumors involving overgrowth of functional endocrine tissue
        
        ex. Pheochromocytoma is tumor of adrenal medulla that secretes excessive amounts of eopinephrine and norepinephrine.
        
        ex. Lung tumors can secrete ACTH and overstimulate cortisol secretion in adrenal gland
      - Autoimmune disorders
        
        Toxic Goiter
        
        autoantibodies mimic the effect of TSH on the thyroid, activating TSH receptor and causing thyroid hypersecretion
  - - - hypersecretion of GH in childhood/adolescence (before epiphysial plates - growth zones are depleted)
    - - hyposecretion of GH...
        
        become rare as GH is more plentiful now
    - - hypersecretion in adulthood causes thickening of bones, soft tissues, etc. most noticeable in hands, feet, face
  - - - thyroid hyposecretion from birth
    - - severe/prolonged adult hypothyroidism
        
        treated by oral TH
    - - deficiency of dietary iodine, without it the gland cant synthesize TH, so the pituitary gland receives no feedback and continues to secrete TSH, making the Thyroid produce more thyroglobulin, so it accumulates in the neck
    - - Parathyroids are often degenerated or removed accidentally in thyroid surgery
        
        without horomone replacement therapy it can result in
        
        2-3 days the decline in blood calcium level can result in fatal suffocating spasm of the muscles of the larynx
    - - usually cause by parathyroid tumor, causing bones to degenerate
  - - - excess Cortisol secretion, leads to
        
        muscle and bone loss from protein catabolism
        
        abnormal fat deposition
        
        moon face and buffalo hump
    - - Adrenal androgen hypersecretion (accompanies Cushing)
      - enlargement of external sexual organs in children and early onset of puberty, masculinized features on women
- - - - Half Life (T 1/2)
  - - - 2 of the 4 principle communication mechanisms:
        
        Gap Junctions
        
        pores in cell membranes allowing signaling molecules to move between
        
        Neurotransmitters
        
        Paracrines
        
        Secreted in tissue fluids to affect nearby cells, (local)
        
        Histamines
        
        from mast cells in connective tissue
        
        relaxation of blood vessel
        
        Nitric Oxide
        
        from endothelium of blood vessels
        
        causes vasodilation
        
        Catecholamines
        
        diffuse from Adrenal medulla to cortex
        
        Eicosanoids
        
        family of paracrine that have 20 carbon backbones derived from fatty acid called
        
        Arachidonic Acid
        
        2 more items...
        
        Hormones
        
        2 main types:
        
        Proteins
        
        Steroid
        
        very small
        
        10^-6 g (ug)
        
        10^-9 (ng)
        
        10^-12 g (pg)
        
        Autocrines
        
        stimulate the same cell that secreted them
        
        a single chemical can act as a hormone, paracrine, or even neurotransmitter in different locations
- - - - 1st Stage
        
        Alarm Reaction
        
        Initial response - mediated by
        
        Norepinephrine from the SNS and Epinephrine from Adrenal Medulla
        
        prepares body for fight/flight
        
        stored glycogen is consumed
        
        increases aldosterone and angiotensin levels
        
        Aldosterone promotes Na and H2O conservation
        
        Angiotensin helps raise blood pressure
      - 2nd Stage
        
        Stage of Resistance
        
        After a few hours, glycogen is gone, but brain still needs glucose
        
        provide alternate fuels for metabolism
        
        stage dominated by cortisol
        
        Cortisol has glucose-sparing effect- inhibits protein synthesis leaving free amino acids for gluconeogenesis
        
        but it
        
        depresses immune function
        
        increases susceptibility to infections and ulcers
        
        lymphoid tissues atrophy, antibody levels drop, wounds heal poorly
        
        Hypothalamus secretes CRH (corticotropin releasing hormone)
        
        Pituitary secretes ACTH
        
        Adrenal Cortex secretes cortisol and other glucocorticoids
      - 3rd Stage
        
        Stage of Exhaustion
        
        when stress continues for several months
        
        fat reserves are gone
        
        homeostasis is overwhelmed
        
        rapid decline, death
        
        protein breakdown + muscle wasting
        
        adrenal cortex stops producing glucocorticoids, leads to loss of glucose homeostasis
        
        aldosterone promotes water retention and hypertension
        
        conserves sodium and hastens elimination of K+ and H+
        
        heart and kidney infection or overwheming infection