Review - PA School Flashcards
Amine hormones are derived from
Tyrosine
Steroid hormones are derived from
Cholesterol
The majority of hormones are this type of molecule
Peptide / protein
Amine hormones include:
1) catecholamines (dopamine, norepinephrine, epinephrine)
2) thyroid hormones ( thyroxine-T4 & triiodothyronine-T3)
Steroid hormones include
1)Glucocorticoids (cortisol & aldosterone)
2)sex steroids (estradiol, progesterone, estrogen, testosterone, DHEA)
Vit D?
Which hormones are hydrophobic and primarily inactive bound to proteins in blood stream?
Thyroid and steroid based hormones
This type of hormone is not stored; it is released immediately following synthesis
Steroids
Hormones released by anterior pituitary (6)
Adrenocorticotrophic hormone ACTH
Growth hormone GH
Thyroid stimulating hormone TSH
Prolactin PRL
Lutenizing hormone LH
Follicle stimulating hormone FSH
Hormones released by posterior pituitary (2)
Oxytocin OT
Argine vasopressin AVP
Neurovascular connections between hypothalamus and pituitary
Magnocellcular neurons connect directly to posterior pituitary
Parvicellular neurons stimulate release of releasing hormones in median eminence which flows down portal veins to anterior pituitary
Hypothalamic releasing hormones
Stimulating: GHRH, TRH(impacts TSH and PRL), CRH, PRF, and GnRH (LH and FSH)
Inhibitory: somatostatin (GH and TSH) and dopamine (PRL)
Effects of oxytocin
1) uterine contraction
2) milk let down
3) blood pressure via cardiac receptors and NO release in vasculature
Triggers for AVP release
1)Dehydration
2)Loss of water from osmoreceptors
3)Increased Na or Cil
Effect of AVP
1)Acts on V2 receptors in kidney to increase resorption via aqua potions 1-4
2) stimulates thirst receptors
The majority of GH secretion occurs
1) At night (70%)
2) during childhood and adolescence
GH release is inhibited by…
Somatostatin
Aging
Obesity
GH
IGF1
Increased FFA
Hyperglycemia
GH release is stimulated by…
Hypoglycemia
Decreased FFA
Arginine
Fasting/starvation
Exercise
Stress
Sleep
Thyroid hormone
Androgens
Gherlin
GH effects
Protein anabolism
Lipolysis
Increased hepatic gluconeogenesis + insulin release = diabetogenic effect
IGF1 actions
Increased lean body mass
Increased organ size and function
Increased linear bone growth
In the fed state
Increased GH facilitates insulin action to promote growth
(Except when just carbs are ingested, then hyperglycemia suppresses GH and energy is stored)
In faster state GH
Increases in response to hypoglycemia increasing lioplysis and hepatic gluconeogenesis.
IGF1 goes down
HPT axis become functional at this point
12wk gestation
Cretinism
Results from Thyroid deficiency during gestation
Calcitonin is released by
Parafollicular cells in the thyroid
Thyroid hormone is synthesized in the _______ cell and stored in the ________.
Follicular
Colloid
Function of thyroid peroxidase
Enzyme involved in oxidation of iodine and its incorporation into tyrosine
Dietary iodine requirements
400mcg
Wolff-chaikoff effect
Temporary inhibition of thyroid hormone synthesis due to excess dietary iodine
T3 is ____x more potent at stimulating TR than T4
10
Effects of thyroid hormone
- Increases BMR
2.increases glucose absorption, gluconeogenesis, and lipolysis - Cardiac stimulation
4.increased beta adrenergic receptors
Thyroid hormone function in fetal development
Critical for bone and CNS development
