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Endocrine System - Coggle Diagram

- - - - Fast delivery of hormones
    - - Follicular produces T3 + T4
        
        Regulate basal metabolic rate
        
        Influence growth/maturation of nervous tissue
      - Parafollicular produces calcitonin
        
        Regulates blood calcium levels in conjunction with parathyroid hormone
        
        Recognised by extensive unstained cytoplasm
        
        Inhibits osteoclast activity
        
        Less bone resorption
        
        Stimulates osteoblast activity
        
        More bone formation
        
        Antagonist effects to parathyroid hormone
  - - - Tri-iodothyrine
  - - - Contains precursors to thyroid hormone
  - - - Lack of thyroxine from birth or before birth
      - Possibly from lack of thyroid gland or lack of iodine in mother
      - Irreparable mental defects
      - Stunted growth
      - Reduced growth + function of many organs
    - - Severe hypothyroidism undiagnosed or unsuccessfully treated
      - Drowsiness + confusion
      - Hypothermia
      - Skin changes
        
        Myxoedema crisis/coma
    - - Swelling of neck resulting from enlarged thyroid
      - Lack of iodine in diet
      - Over or underproduction of thyroid hormones or nodules in gland itself
      - Usually small + no symptoms caused
- - - - Neuroendocrine organ
  - - - Neuroendocrine organ
  - - - Simple
      - Water soluble
      - Produced from amino acid
      - Thyroxine
        
        Thyroid gland
      - Epinephrine
        
        Adrenal gland (medulla)
    - - Water soluble
      - Chains of amino acids
      - Oxytocin
        
        Hypothalamus
      - Insulin
        
        Pancreas
      - Pituitary hormones (GH, LH etc)
        
        Anterior pituitary
      - Calcitonin
        
        Thryoid
      - Parathyroid hormone
        
        Parathyroid
    - - Lipid soluble
      - Derived from cholesterol
      - Aldosterone
        
        Adrenal cortex
      - Testosterone
        
        Testis
      - Oestrogen/progesterone
- - - - Adenohypophysis (anterior pituitary)
        
        Pars distalis/anterior
        
        Largest part of organ
        
        2 types cell
        
        Chromophobes
        
        Chromophils
        
        Cell secretory cycle
        
        Chromophobes
        
        Chromophils
        
        Acidophils \(\alpha\) cells/ basophils \(\beta\) cells
        
        2 more items...
        
        Pars intermedia
        
        Vascular
        
        Solid cords of non-granular epithelial cells
        
        Pars tuberalis
        
        Small
        
        Less vascular
        
        Cells usually clear
      - Neurohypophysis (posterior pituitary)
        
        Pars Nervosa
        
        Functional
        
        Groups of axons of neurosecretory cells
        
        Mainly originating from hypothalamus
        
        Blood vessels + connective tissue
        
        Herring bodies/neurosecretory bodies
        
        Structures in posterior pituitary
        
        Represent terminal end of axons from hypothalamus
        
        Temporary storage of hormones
        
        Neurosecretory terminals
        
        Pituicytes
        
        Neuroglia type cells
        
        Supportive not secretory
        
        Infundibulum
        
        Hollow stalk connecting hypothalamus to pituitary
    - - Anterior/posterior lobes
        
        Cleft in young
        
        Isolated cysts in adult
      - Pregnancy
        
        Anterior lobe 135% larger
        
        Oestrogen-stimulated hyperplasia + hypertrophy
        
        Prolactin cells (ensure lactation)
      - Puberty
        
        Growth spurt associated with increase in pars anterior
        
        Alpha cells produce more hormone
      - Hyperpituitarism
        
        Increased secretion of one or more hormones normally produced
        
        e.g. pituitary adenoma producing growth hormone
        
        Induces gigantism if condition develops before union of epiphyses of long bones in childhood
        
        Induces acromegaly if condition after union, when bony overgrowth causes somatic enlargement in face and extremities
      - Hypopituitarism
        
        Decreased secretion of one or more hormones usually produced
        
        e.g. pituitary dwarfism - decreased GH
    - - Somatotropes
        
        Growth hormone
      - Lactotropes
        
        Prolactin
    - - Thyrotropes
        
        Thyroid stimulating hormone
      - Gonadotropes
        
        Luteinising hormone
        
        Follicle-stimulating hormone
      - Corticotropes
        
        Adrenocorticotrophic hormone
  - - - Adenomas
    - - Trichrome
      - Trichrome + PAS
- - - - Chief (principal) cells
        
        Most abundant
        
        Secretes parathyroid hormone
        
        Structure
        
        Prominent nucleus
        
        Little cytoplasm
        
        Staining intensity
        
        Dependent on degree of secretory activity
      - Oxyphil cells
        
        Produce additional autocrine + paracrine factors
        
        Functions + secretions not fully known
        
        Structure
        
        Larger, less numerous than chief cells
        
        Small densely stained nuclei
        
        Strongly eosinophilic cytoplasm
  - - - Calcium deficiency due to hypoparathyroidism
      - Neurones depolarise w/out usual stimulus
        
        Increased nervous impulses
        
        Twitches
        
        Spasms
        
        Convulsions
    - - Blood phosphate decreased + calcium increased
        
        Pathological deposits of calcium in organs
        
        Kidneys
        
        Arteries
      - Arising from hyperparathyroidism
      - Increased activity and no. osteoclasts
        
        Bones less resistant, prone to fracture
- - - - Adrenal cortex
        
        Hormones related to cholesterol
        
        Mineralocorticoids
        
        Glucocorticoids
        
        Sex hormones
      - Adrenal medulla
        
        Specialised to adjunct sympathetic NS
        
        Secretes catecholamines
        
        Adrenaline (epinephrine)
        
        Noradrenaline (norepinephrine)
    - - Zona glumerulosa
        
        Cells in irregular ovoid clumps
        
        Round, strongly stained nuclei
        
        Sparse cytoplasm
        
        Abundant smooth ER + mitochondria with triglyceride droplets
        
        Secretes mineralocorticoid hormones
      - Zona fasciculata
        
        Intermediate + broadest zone
        
        Large secretory cells
        
        Abundant cytoplasm
        
        Secretes glucocorticoid hormones
      - Zona reticularis
        
        Thin, innermost layer
        
        May be responsible for small secretions of sex hormones
    - - Small, closely packed clumps of secretory cells
        
        Large granular nuclei
        
        Strongly basophilic cytoplasm
      - Chromaffin cells secrete catecholamine hormones
  - - - Over-secretion of aldosterone
    - - Decreased potassium, increased sodium
    - - Increased potassium, decreased sodium
        
        Low blood pressure
    - - Increased production of glucocorticoids e.g. cortisol
- - - - Involutes rapidly at puberty
    - - Pineal chief cells (pinealocytes)
        
        Modified neurones
      - Neuroglial cells
        
        Similar to astrocytes
    - - Appearance of basophilic extracellular bodies
        
        Corpora Arenacea
        
        Pineal/brain sand
        
        Calcified structures in pineal gland
        
        Seen on x-rays of skull
        
        Guide for location of pathological conditions
  - - - Circadian rhythms i.e. sleep and wake
    - - Secretion of melatonin inhibited by light + triggered by darkness
    - - Melatonin suppresses production of Gonadotrophin Releasing Hormone (GRH) by hypothalamus
        
        Thus suppressing pituitary gonadotrophin secretion/activation of gonadal growth + hormone secretion
- - - - Clumps of secretory cells
      - Supported by fine reticular network containing numerous fenestrated capillaries
        
        Fenestrated - leaky
      - Small cells with poorly stained cytoplasm surrounded by pancreatic tissue
      - Greater amount of RER in exocrine cells
        
        Secrete protein
    - - Alpha 20%
        
        Secrete glucagon
      - Beta 70%
        
        Secrete insulin
      - Delta 5%
        
        Secrete somatostatin
      - Indistinguishable with H&E
        
        Specialised tinctorial stains or immunohistochemistry to identify individually
  - - - Partial/total destruction of \(\beta\) cells
      - Autoimmune disease
        
        Susceptibility controlled by several genes
    - - Occurs later in lafe
      - Associated with obesity
    - - May produce insulin, glucagon, somatostatin + pancreatic polypeptide
      - Some produce 2 or more of hormones at once
        
        Complex clinical symptoms
- - - - Slow-growing neuroendocrine tumour
      - Several vasoactive substances produced
        
        Prominently serotonin
        
        Increased gut motility
        
        High levels associated with mucosal vasoconstriction + damage