Please enable JavaScript.
Coggle requires JavaScript to display documents.
Hypothalamic-Pituitary Physiology and Disorders - Coggle Diagram
Hypothalamic-Pituitary Physiology and Disorders
Physiology
Pituitary gland
Characteristics
Pea sized gland behind bnridge of nose attached to base of brain
Sits right below the evers to the eyes in the sella turcica
Divide into 2 main portions: Anterio and posterior pituitary
Controlled by hypothalamus
Anatomical structures
Superior
Optic chiasm
Inferior
Spenhoid sinus
Lateral
Cavernouse sinus (cranial nerves, ICA)
Development
Organ of dual oriign: anterior lobe from epithlium and posterior from neuroectoderm
Histology
Adenohypophysis
Acini of hormoen producing cells
Basophils, acidophils, and chromophobes
Neurohypophysis
Composed of axons fro hypothalamic neurons and contains oxytocin or vasopresin
Hormones
Posterior
Oxytoxin: Distensin of vagina, cervix and nipple stimulation stimulates uterine contraction and milk release
Vaspressin: ADH which is regulated by plasma osmolality, increases free water absorption
Anterior
Prolactin: Effects to allow for lactation, and suppression of LH/FSH, it is inhibited by dopamine
Growth Hormone
Effects growth and is mediated throguh IGF-1
Controlled by GHRN and somatostatin (inhibits)
Also controlled metabolic with glucose, and in hyupoglycemia GH increase, protein releases GH whereas fatty acids suppress GH
ACTH:
From POMC and causes secretion of glucocoritocid and androgens from adrenal cortex
REleasesd by stress, and by hypothalamic hromones, CRH, vasopressin, angiotensin 2
Thyroid Stimualting hormone
Controlled by TRH
Stimualtes thyroid gland to grow, incorporate idoine, syntehsize and release thyroid hormones
Hypothalamus
Role
Integration centre, pituitary congls, sexual activity, appetitie, water and caloric balance
Will produce releassing hormones that go onto pituitary that act on taget organ that will replace hormones that act as a negative feedback
HPA Hormones
GnRH: FSH,LH
GHRH -> GH
TRH -> TSH
VIP/PHI-27 -> Prolactin
CRH/Vasopresin: ACTH
Somatostatin: Inhibits growth hormone and TRH re3lease
Dopamine: Inhibits prolactin secretion
Pathologies
Pituitary Masses
Pituitary Adenomas
Can be secreting or non secretion (non functioning more common)
Symptoms
Headahce, optic chiasm (loss of peripheral vision), CN palsies, sphenoid sinus
Disorders that lead to hypopituitarism
Tumors (putitary adenoma), granulomas (sarcoid,TB), vascular (necrosis, carotid aneurysm), trauma (stalk section), infiltration, autoimmune, empty sell syndrome, congenital deficiencies
PresentationP
CRH: Adrenal insufficiency
GnRH: Delayed puberty, libidy, body hair, amenorrhea, infertiity
TRH: Hypothyroid
GHRH: CHildren: Short stature, adults - pale, decreased muslce mass, energy, fine skin
Prolactin: Failure to lactate post-partum
Oxytocin: No clinical efects
ADH: Diabetes insipidus
Investigations
Biochemical: Can measure anterior pituitary and target organ hormones (ACTH + cortisol, TSH + FT4/3, FSH, LH + estrogen/test, GH + IGF-1, electrolytes, urine and serum osmolality)
Stimulation studies
Radiographical studies
Treatment
Hypopituitary
Replace with hormone or product
ACTH - Cortisol, GH - GH, TSH - Thyroid hormone, prolactin - none, LH/FSH - test or estrogen, ADH - DDAVP
Disorders of Hypersecretion
Hyperprolactinemia
Increased galactorrhea, decrease LH/FSH
Causaes
Physiological stimuli (sleep, excercise, pregnancy, stress), pahtmacological (estrogen, dopamine antagonists, cimetidine), pathological (tumors, stalk lesions, chest wall lesion, spinal cord lesion)
Diagnosis
baseline prolactin level, TSH, creatinine, BHCG to rule out other causes
Treatment
3 option
Medical (dopamine agonists)
Radiation
Surgery
Acromegaly
Biochemical
Diagnosis
High IGF, lack of suppresion from oral glucose
Treatment
Sutrgical
Medical (somatostatin or bromocriptine to suppress GH, pegvisomant to block GH receptor)
Radiation
Cushings Disease
Cause by ACTH secreting pituitary adenoma
Features
Fat redistribution/weight gain, hyperglycemia, hypertension, thinning skin,e asy brusie, mood changes
Diagnosis
Hypercotisolemia (increased 24 hr urine cortisol, failure for dexamethasome suppresion
Treatment
Surgical, medical therapy (adrenal targeted, pituitary targetied), radiation
TSH Secreting Adenomas
DIagnosis
Hyperthyroidism with elevated TSh
Treatment
Surgery/MEdical