Please enable JavaScript.

Coggle requires JavaScript to display documents.

ENDOCRINOLOGY - Coggle Diagram

- - - - FOLLICLE CELL --> thyroid hormone
        
        C CELLS --> calcitonin
  - - - CATHECOLAMINES
        
        DOPAMINE - ADRENALINE (80%) / NORADRENALINE
        
        hormones are secreted and stored in adrnal medulla --> released in response to appropriate stimula
        
        E vs NE
        
        E >> NE: in terms of cardiac stimulation --> greater CO (beta stimulation)
        
        E < NE: constriction of blood vessel --> HIGH peripheral resistance --> HIGH arterial pressure
        
        E >> NE: increasing metabolism --> Epi = 5-10x NE
        
        effects of E
        
        METABOLISM
        
        GLYCOGENOLYSIS - in liver & skeletal muscle --> hyperglycemia
        
        mobilization of FFA
        
        increased metabolic rate --> HIGH O2 consumption
      - CLINICAL
        
        PHEOCHROMOCYTOMA
        
        A catecholamine-secreting tumour of chromaffin cells of AM
        
        adrenal pheochromocytoma (90%)
        
        paraganglioma - a catecholamine secreting tumour of sympathetic paraganglia --> extra-adrenal pheo.
        
        SIGNS
        
        treatment resistant hypertension (95%)
        
        headache
        
        sweating
        
        palpitation
        
        chest pain
        
        anxiety
        
        glucose intolerance
        
        increased metabolic rate
        
        treatment
        
        1 more item...
      - CORTICOSTEROIDS
      - MINERALCORTICOID
        
        ALDOSTERONE
        
        DEFICIENCY
        
        increased NA+, Cl-, H2O loss
        
        decrease ECF volume
        
        hyperkalemia - mild acidosis
        
        increase RBC con.
        
        decrease CO --> shock,
        death within 4 days - 2weeks if not treated
      - GLUCOCORTICOID
        
        CORTISOL
        
        DEFICIENCY
        
        disruption in glu conc.
        
        reduction in metabolism of fats & proteins
        
        susceptible to stress
        
        slugghishniess of energy mobilization --> weak muscle even when glucose & other nutrients available
        
        MELANIN
        
        PIGMENTATION
- - - - Reproduction
        
        Growth and development
        
        Maintenance of electrolyte, water, nutrient balance of blood
        
        Regulation of cellular metabolism and energy balance
        
        Mobilisation of body defence
        
        MECH
        
        HORMONAL ACTION
        
        • Alter plasma membrane permeability of membrane potential by opening or closing ion channels
        • Stimulate synthesis of proteins or regulatory molecules
        • Activate or deactivate enzyme systems
        • Induce secretory activity
        • Stimulate mitosis
        
        cAMP signaling mechanism
        
        Plasma Membrane Receptors and Second-Messenger Systems
        
        Activated kinases phosphorylate various proteins, activating some and inactivating others
        
        cAMP is rapidly degraded by the enzyme phosphodiesterase
        
        Intracellular enzymatic cascades have a huge amplification effect
        
        PIP2-calcium signaling mechanism
        
        • Cyclic guanosine monophosphate (cGMP)
        
        second messenger for some hormones
        • Some work without second messengers – E.g., insulin receptor is tyrosine kinase enzyme that autophosphorylates upon insulin binding --> docking for relay proteins that trigger cell responses
        
        Target Cell Specificity
        
        Target cells must have specific receptors to which the hormone binds
        
        ACTH receptors are only found on certain cells of the adrenal cortex
        
        Thyroxin receptors are found on nearly all cells of the body
        
        ACTIVATION
        
        FACTORS
        
        Blood levels of the hormone
        
        Relative number of receptors on or in the target cell
        
        Affinity of binding between receptor and hormone
        
        2 more items...
        
        HORMONE
        
        4 more items...
      - Responses occur more slowly but last longer than nervous system
    - - Amino acid-based hormones - Amino acid derivatives, peptides and proteins
      - Steroids
        
        • Synthesized from cholesterol
        • Gonadal and adrenocortical hormones
      - Water-soluble hormones (all amino acid-based hormones except thyroid hormones)
      - Lipid-soluble hormones (steroid/thyroid hormones)
  - - - “Master gland”, hypophysis, 600 mg
        • In hypophyseal fossa, above sella turcica of sphenoid bone
        • Posterior pituitary (neurohypophysis)
        • Anterior pituitary (adenohypophysis)
        
        POST LOBE
        
        (neurohypophysis)
        
        A downgrowth of hypothalamic neural tissue
        
        Neural connection to the hypothalamus (hypothalamic-hypophyseal tract)
        
        Nuclei of the hypothalamus synthesize the neurohormones oxytocin and antidiuretic hormone (ADH)/ VASOPRESSIN
        
        ANT LOBE
        
        (adenohypophysis):
        
        Consists of glandular epithelial cells (adeno = glandular)
        
        Hypophyseal portal system
        • Primary capillary plexus
        • Hypophyseal portal veins
        • Secondary capillary plexus
        
        Carries releasing and inhibiting hormones to the anterior pituitary to regulate hormone secretion
    - - ADRENAL MEDULLA —nervous tissue; part of the sympathetic nervous system
      - ADRENAL CORTEX —three layers of glandular tissue that synthesize and secrete corticosteroids
      - • Paired, pyramid-shaped organs
        atop the kidneys
      - Mineralocorticoids
        
        Aldosterone
        
        Regulate electrolytes (primarily Na+ and K+) in ECF
        
        Importance of Na+: affects ECF volume, blood volume, blood pressure, levels of other ions – Importance of K+: sets RMP of cells
        
        Aldosterone is the most potent mineralocorticoid
        
        Stimulates Na+ reabsorption and water retention by the kidneys; elimination of K+
        
        MECH
        
        Renin-angiotensin mech = decreased blood pressure stimulates kidneys to release renin, triggers formation of angiotensin II, a potent stimulator of aldosterone release
        
        Plasma concentration of K+: Increased K+ directly influences the zona glomerulosa cells to release aldosterone
        
        ACTH: causes small increases of aldosterone during stress
        
        Atrial natriuretic peptide (ANP): inhibits renin and aldosterone secretion, to decrease blood pressure
        
        DEFICIENCY
        
        Autoimmune antibodies attack the adrenal cortex (associated with Addison’s disease)
        
        Hyperkalemia – K+ retention; caused by reduced K+ loss in the urine; disturbs cardiac rhythm
        
        Hyponatremia – Na+ depletion; caused by excessive urinary loss of Na+; reduces ECF volume, lowers blood pressure (hypotension)
        
        Glucocorticoids (Cortisol)
        
        only significant glucocorticoid in humans
        
        Released in response to ACTH, patterns of eating and activity, and stress
        
        Prime metabolic effect is gluconeogenesis—formation of glucose from fats and proteins
        
        Promotes rises in blood glucose, fatty acids, and amino acids – saves glucose for brain
        • Keep blood sugar levels relatively constant
        • Maintain blood pressure by increasing the action of vasoconstrictors
        
        Homeostatic Imbalances
        
        HYPERSECRETION
        
        Cushing’s syndrome
        
        HYPOSECRETION
        
        Addison’s disease
  - - - • All are proteins
        • All except GH activate cyclic AMP second-messenger systems at their targets
        • TSH, ACTH, FSH, and LH are all tropic hormones (regulate the secretory action of other endocrine glands)
        
        HORMONE
        
        Growth hormone (GH)
        
        • Thyroid-stimulating hormone (TSH) or thyrotropin
        
        TH
        
        Actually two related compounds
        -T4 (thyroxine); has 2 tyrosine molecules + 4 bound iodine atoms
        
        T3 (triiodothyronine); has 2 tyrosines + 3 bound iodine atoms
        
        Affects virtually every cell in body
        
        Major metabolic hormone
        • Increases metabolic rate and heat production (calorigenic effect)
        
        Plays a role in
        • Regulation of tissue growth
        • Development of skeletal and nervous systems
        • Reproductive capabilities
        
        Transport and Regulation
        
        1 more item...
        
        Homeostatic Imbalances
        
        2 more items...
        
        • Adrenocorticotropic hormone (ACTH)
        
        Secreted by corticotrophs of the anterior pituitary
        • Stimulates the adrenal cortex to release corticosteroids
        
        REGULATION
        
        RELEASE
        
        • Triggered by hypothalamic corticotropin-releasing hormone (CRH) in a daily rhythm
        • Internal and external factors such as fever, hypoglycemia, and stressors can alter the release of CRH
        
        • Follicle-stimulating hormone (FSH)
        
        • Luteinizing hormone (LH)
        
        • Prolactin (PRL)
- - - - FIXED COMM SYS
        
        intracellular comm mech are needed to adapt to a constant changing envi
        
        endocrine sys
        
        represent a class of hormones that arise in one tissue or ‘gland’ and travel a considerable distance through the circulation to reach a target cell expressing cognate receptors located at cell surface.
        
        endocrine - transmit info via hormone secreted into blood and ECF
        
        receptor - hormone specific
        
        CELLS/ORGANS THAT SECRETE HORMONES - ENDOCRINE GLANDS
        
        HORMONE
        
        DETERMINANTS of the concentration of a
        hormone at the target cell
        
        1 more item...
        
        Determinants of the target cell response
        
        1 more item...
        
        classified according to:
        
        2 more items...
        
        types
        
        4 more items...
        
        General features
        
        2 more items...
        
        factor
        
        1 more item...
    - - MOBILE MESSAGE
        
        interaction btw the systems
        
        HORMONE
        
        ENDOCRINE
        
        w/out ducts
        
        secrete into blood / ECF
        
        transported to target cell
        
        NEUROCRINE
        
        hormone produced by nerve cells
        
        acts trans-sinaps (neurotransmitter)
        
        eg: noradrenalin
        
        Excitatory: Glutamate, adrenaline, noradrenaline etc.
        
        Inhibitory: GABA, glycine, serotonin etc.
        
        Neurocrine system does not produce hormone, unlike neuroendocrine system.
        
        Neuron secretes signal molecule e.g. neurotransmitter
        
        Acts on receptors on neighbor (gland, another neuron or muscle)
        
        Acts locally, like paracrine
        
        NEUROENDOCRINE
        
        produced by nerve cells.
        
        secreted into blood system
        
        eg: hypothalamic hormones - post. pituitary hormone
        
        *Neuroendocrine cells - receive signal from nervous system
        
        making/releasing hormones
        
        PARACRINE
        
        stimulate/ inhibit hormone secretio of adj cell
        
        doesnt enter general blood circulation
        
        eg: glucagon stimulates insulin secretion
        
        Arise from a cell and travel a relatively short distance to interact with their cognate receptors (cell-to-cell interaction) on another neighboring cell.
        
        AUTOCRINE
        
        acts on self
        
        target sites on the cell secreting the hormone
        
        e.g. action of insulin on pancreatic beta cells
        
        are produced by the same cell that functions as the target for that hormone (neighboring cells may also be targets)
    - - HORMONE
        
        CORTISOL
        
        control blood sugar levels, regulates metabolism,
        
        help reduces inflammation, and
        
        assists with memory formulation.
        
        It has a controlling effect on salt and water balance and
        
        helps control blood pressure.
        
        Corticotropin -releasing hormone (CRH) is secreted by the paraventricular nucleus (PVN) of the hypothalamus in Cortisol response to stress.
      - METABOLITE
      - NERVOUS SYS
        
        SYNTHESIS & RELEASE OF
        
        HYPOTHALAMIC H.
        
        POST PITUITARY H.
        
        ECTOPIC H
        
        There are several syndromes of hormone hypersecretion that are caused by the unregulated production of hormones, usually by tumour.
        
        Ectopic hormone production involves the synthesis and secretion of peptide or protein hormones by benign or malignant tumours of tissues that do not normally synthesize and secrete the particular hormone.
        
        The hormone that is most commonly produced ectopically is adrenocortico-tropic hormone (ACTH), resulting in ectopic Cushing syndrome.
        
        synthesis ectopic h. --> extra endocrine gland cells (only involve peptide h.)
        
        eg: GHRH (neuroendocrine tumour in lungs), ACTH by lung tumour, hCG by trophoblast tumour
        
        CATECHOLAMINES
        
        TRANSPORT
        
        PROTEIN
        
        circulate in free form
        
        hydrophilic
        
        easily degraded
        
        short half-life
        
        STEROID & THYROID H
        
        HYDROPHOBIC
        
        BOUND TO TRANSPORT PROTEINS
        
        LONGER HALF-LIFE
        
        ONLY FREE FORM ARE BIOLOGICALLY ACTIVE