Endo 2 Flashcards
Is the anterior pituitary gland a true endocrine organ?
yes
is the posterior pituitary gland a true endocrine organ?
no
-contains axon terminals of hypothalamic neurons
Where is the pituitary gland located?
in the sella turcica
What hormones are released from the anterior pituitary?
growth hormone
ACTH
TSH
FSH
LH
prolactin
What hormones are released from posterior pituitary?
ADH/vasopressin
oxytocin
What type of cells secrete GH?
somatotrophs
What type of cells secrete ACTH?
corticotrophs
What type of cells secrete TSH?
thyrotrophs
What type of cells secrete LH nad FSH?
gonadotrophs
What type of cells secrete prolactin?
mammotrophs
Where are hypothalamic hormones released into?
primary capillary plexus in the median eminence
What carries the hypothalamic hormones to the sinuses of the anterior pituitaryt?
hypothalamic-hypophyseal portal blood vessels
How does GH function?
it can act directly on the tissue or act as a tropic hormone to the liver
-causes the release of insulin like growth factor in the liver
How is GH released?
in a pulsatile manner
-lower during the day with highest levels a few hours after sleep
What stimulates the release of GH?
starvation, fasting, stress, exercise, and excitement
How does the secretion of GH change throughout life?
-high during neonatal period
-decreases in childhood
-peaks during puberty
-declines with age after puberty
Where is IGF-1 made?
in most tissues and act as a neighboring cells in a paracrine manner
-major site of synthesis is in the liver
What is the mechanism of action in GH and IGF-1?
-growth in nearly all tissues in the body (increase organ size, increase organ function, increase in linear growth)
-amino acid uptake and protein synthesis in most cells (increase lean body mass)
-reduce glucose utilization (decrease uptake, increase hepatic glucose production, and increase insulin secretion)
-mobilization of fatty acids from adipose tissue resulting in increases FFA in blood and use of FFA for energy
What does GH and IGF-1 do in bone deposition prior to the fusing of epiphyseal plates?
stimulates chondrogenesis and widening of epiphyseal plates, following by bone matrix depositions (linear growth)
How does GH and IGF-1 do to bones in an adult?
increases bone formation by activating osteoblasts and osteoclasts
What is excess growth hormone called in children?
gigantism
What is excess GH called in adults?
acromegaly
What is the cause of 90% of acromegaly?
pituitary tumor
What are some symptoms of excess GH?
-coarse facial features, large fleshy nose, frontal bossing, jaw malocclusion
-coronary heart disease
-diabetes mellitus
-kyphosis
-paresthesias
-hyperhidrosis and oily skin
What is the treatment for pituitary microadenoma?:
surgical resection of tumor via transsphenoidal approach followed by treatment in GHIH
What are the oral manifestations of GH excess?
-thick, rubbery skin, enlarged nose, and thick lips
-macrocephaly
-macrognathia
-mandibular prognathism
-generalized diastemata
-anterior open bite and malocclusion
-macroglossia, dyspnea, dysphagia, dysphonia, sialorrhea
-hypertrophy of pharyngeal and laryngeal tissues -> sleep apnea
What can cause a deficiency of GH?
-hypothalamic disorders
-mutations in GHRH receptor, GH gene, GH receptor, IGF-1 receptor
-combined pituitary hormone deficiencies
-radiation
-psychosocial deprivation (causes an increase in GHIH)
What are the clinical manifestations of complete GH deficiency?
-slow linear growth rates
-normal skeletal proportions
-pudgy, youthful appearance (decreased lipolysis)
-in the setting of cortisol deficiency (hypoglycemia)
What is the most common form of dwarfism?
achondroplasia
What causes achondroplasia?
mutation in FGF-3 receptors in cartilage and brain
-makes receptor over active and inhibits cartilage growth at growth plates
What are the oral manifestations of GH deficiency?
-disproportionate delayed growth of skull and facial skeleton
-tooth formation and growth of alveolar regions in the jaw are abnormal (tooth crowding and malocclusion, high tendency for plaque accumulation, difficulty maintaining good oral hygiene, and prone to gingivitis and periodontal disease)
-solitary median maxillary central incisor
-delayed eruption of primary and secondary dentition
What is solitary median maxillary central incisor?
when an individual only has one maxillary central incisor
How does vasopressin effect blood vessels?
contraction of vascular smooth muscle via V1 receptors
-raise blood pressure
How does vasopressin effect renal tubules?
-bind to V2 receptors in late distal tubules and collecting duct
-aquaporin-2 proteins are inserted into the apical membrane of tubular epithelial cells
-allow more water resopriton
What stimulates ADH secretion?
-decreased blood volume (isotonic)
-increased osmolarity (isovolemic)
-decreases blood pressure
What is hypodipsia?
decreases or absent feeling of thirst which results in reduced intake of water
What does neurogenic diabetes insipidus do to ADH?
decrease levels
What does nephrogenic diabetes insipidus do to ADH?
increase levels
What is syndrome of inappropriate ADH?
increases and uncontrolled of ADH that causes volume expansion and hyponatremia
-decrease Na
-decrease nerve and muscle excitability
-can result from surgery, pain, stress, temperature changes, tumor, etc
What are the actions of oxytonic?
released from posterior pituitary
-stimulate contraction of uterus toward the end of gestation
-cause milk ejection from breasts in lactation
What is pitocin?:
synthetic oxytocin that is given to induce labor
What is a sign of a disease?
objective evidence of disease that can be seen or measured
What is a symptom of a disease?
something that cannot be measured but are reported by the person
