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(6) Endocrine (Hormones (Thyroid/Parathyroid
Estrogen limits resorption
…
(6) Endocrine
Hormones
Hypothalamus
Inducing
-
Gonadotropin Releasing Hormone --> FSH & LH (Anterior Pituitary)
Thyrotropin Releasing Hormone--> Thyroid Stimulation Hormone & Prolactin (Anterior Pituitary) --> T3/T4 (Thyroid)
-
Inhibiting
Somatostatin (Actually from delta cells in GIT also)--> Growth Hormone & TSH (Anterior Pituitary)
-
Pituitary
Posterior Pituitary
- Vasopressin
- Triggered by pain
- Not triggered by alcohol (alcohol is a diuretic)
- Oat cell carcinoma in lung (Ectopic production)
- Oxytocin
- Stored in pars nervosa
- Produced in diencephalon (Hypothalamus)
- Child birth
Anterior Pituitary
ACTH
- Cortisol from Adrenal Gland
- Instances where ectopic production from lung cancer
GH
- Amino acid derivative
- Regulation: GHRH / T3 / T4 / Somatostatin
- Increases with exercise
- Increases with stress / sleep
- Increase amino acid arginine
- Stimulates produce
- Acromegaly (Increased GH production)
TSH
- T4 (thyroxine) more stable, measure
- T3 (Triiodothyronine) more biologically active
- Brain development (perinatal)
- Growth (affect GH production)
- Thermogenic action
PRL
- Main control is Dopamine (Inhibitory), not Thyrotropin (Inducible)
LH / ICSH
- Most related to ovulation
-
Thyroid/Parathyroid
- Estrogen limits resorption
- Menopause keep resorbing
- Inc PO4, decrease resorption kidney
Thyroid
Thyroid Hormones
- T4 more stable, measure
- T3 more biologically active
- T4 transport, reach organ become T3
- Brain development (perinatal)
- Growth (affect GH production)
- Thermogenic action
- Tyrosine based hormones
T3: Triiodothyronine
- Cardiac output / Heart rate / Ventilation rate
- Basal metabolic rate
- Brain development
- Thickened endometrium
- Increase protein synthesis and catebolism
- Increase carbohydrate catabolism
- Decrease lipid synthesis
T4: Thyroxine
- Basal metabolic rate
- Brain development
Calcitonin
- By parafollicular / C cells in thyroid
- Stimulated by high plasma [Ca]
- Bone decrease resorption
- Kidney decrease calcium reabsorption
- Kidney no effect on PO4
- Gut no effect
- Osteoblast activity increase
*Excess Calcitonin does not cause hypocalcemia
Parathyroid
- Stimulated by low plasma [Ca2+]
- Bone stimulate resorption
- Kidney increase Ca reabsorption
- Kidney decrease PO4 reabsorption
- Stimulation conversation of 25-hydroxy VitD into 1,25 VitD (In Kidney)
- (Pseudo-increase) No effect on Gut (acts on Vitamin D 1,25 hydroxy d3)
- BUT increases activity of enzyme 1-a Hydroxylase
- Which is the step where Kidney
Related Vitamin D
- Inactive form: Vitamin D3/Cholcalciferol; Mostly skin (In contact with UVB); Some diet
- Hydroxylation in Liver (1): 25-Hydroxycholecalciferol
- Hydroxylation in Kidney (2): 1,25-Dihydroxycholecalciferol (Cacitriol)
- Bone resorption
- Kidney reabsorption of Ca and PO4
- Gut absorption of Ca and PO4
FGF23 (Keep PO4 low when trying to inc Ca2+)
- Secreted by osteocytes in response to calcitrol
- Decreases reabsorption PO4
- Increases excretion of PO4
- Reduce ability to activate Vitamin D
- Bring down PO4, while allowing Vitamin D
-
Adrenal (Cortex, Medulla)
Zone fasciculata
- Cortisol
- Inc vascular/Metab, Dep immune/inflam
- Androgen
- Has 17-hydroxylase
- Don't have Aldosterone synthase
- Induced by CRH, ACTH
- Pregnenolone universal precursor
Zona reticularis
- Androgen
- Cortisol
- Inc vascular/Metab, Dep immune/inflam
- Has 17-hydroxylase
- Don't have Aldosterone synthase
- Induced by CRH, ACTH
- Pregnenolone universal precursor
Zona glomeruolsa
- Aldosterone
- Has Aldosterone synthase
- Don't have 17-hydroxylase
- Induced by ACTH & Angiotensin II
- Pregnenolone universal precursor
Regulation of Aldosterone
- Macula Densa (Na JGA) / Barroreceptor
- ACTH (SMALL EXTENT)
- High Potassium
-
Pancreas
- Insulin vs Glucagon, Adrenaline, Cortisol, Growth Hormone
- Adrenaline/Cortisol/GH reduced when Glucose uptake / Glycogen synthesis / Fat synthesis
- Adrenaline/Cortisol/GH increased when insulin is low
-
Bile Salts
- Bile acids conjugated w Glycine & Taurine to become salts
- Primary Bile Acids/Salts (Liver)
- Primary Bile Salt 95% (Ileum)
- Secondary Bile Acid 5% (Deconjugated & Reabsorbed)
Gastric Glands
Mucous Cells: Mucus
Parietal Cells: HCL & Intrinsic Factor
Goblet Cells: Gastrin (Stimulates HCL production)
Chief Cells: Pepsinogen & Lipase
Disorders
Thyroid
Hyperthyroidism
-
Anterior Pituitary Tumour
- Increased/Normal TSH
- Increased T3/T4
- TSH downregulated
- (Paradoxical normal)
Goiter
- Insufficient dietary iodine
- Gland that is producing too much hormones
Hypothyroidism
Hashimoto's Thyroiditis
- Underactive thyroid
- Reduced T3/T4
- Increased TSH
Pituitary Insufficiency/Failure
- Reduced TSH
- Reduced T3/T4
- Cannot upregulate TSH
- No paradoxical normal
Adrenal
Hyperadrenocortical
Cushing Syndrome
- Cushing disease (Specific to pituitary tumour)
- Pharmco/Pituitary tumour
- Ectopic lung cancer
- Increased ACTH & Cortisol
- Pigmentation, melanocytes also increase
-
Hypoadrenocortical
-
ACTH Deficiency
- Pituitary problem
- Reduced ACTH / Steroid
- Causes adrenal hyperplasia
Medullary
Pheohchromocytoma
- Cancer of adrenal medulla
- Excess secretion
Calcium & Bone
- Bound to anions 5-10% (organic/phosphate)
- Bound to proteins 35-50% (albumin)
- Ionized (free) (50-60%)
- Stored in bones
Plasma [Ca2+]
Hypercalcemia
- Respiratory acidosis
- Less free albumin
- More ionized calcium
Hypocalcemia
- Respiratory alkalosis
- More free albumin
- Less ionized calcium
Bone
Osteoporosis
- Vitamin D / Calcium deficiency
Osteomalacia (rickets)
- Vitamin D / Calcium deficiency
Cross-Application (Respiratory Physio):
- Serum albumin can bind to H+
- Prevent Ca++ from binding
- Increase ionized calcium
Glucose Related
Diabetes Mellus
Oral Glucose Tolerance Test (oGTT)
- Standard dose of glucose by mouth
- Blood levels checked 2hrs later
-
-
-
Fasting Glucose Test
- No eating anything for 8hrs
-
-
-
-
Low Blood Glucose
- Cognitive impairment, Weakness
- Coma, Convulsion
- Sweating / Palpitation / Trembling
General
1) Gland
-
Liver is the largest gland: Receives more nutrient rich blood than oxygen rich blood
- Bile
- IFG1 (Insulin Like Growth Factor), promoted by GH
- Angiotensinogen
2) Hormone
Chemical Nature
- Amino acid derivatives
- Peptide/Polypeptide/Proteins
- Steroids (cholesterol derivatives)
-
Secretion
- Basal / Pulsatile
- Regulated (Stimulated/Feedback)
Transport
Primarily Free
- Noradrenaline
- Water Soluble (Like A.A derived)
-
-
3) Target Organ(s)
Receptors
Cell surface receptors (Transduction Cascades eg. TK/GPCR)
- Change in enzyme activity
- Change in gene expression
- Hormones: GH, Norepinephrine, LH, TSH, ACTH, epinephrine, glucagon
Intracellular receptors
- Change in gene expression
- Hormones: T3 (Nucleus, but requires receptor on cell membrane as well), Testosterone, Aldosterone (Steroids)
Post-receptor events
Cyclic AMP
- TSH
- Norepinephrine
- LH/FSH
-
Biological effects:
- Growth & Development
- Reproduction
- Homeostasis
- Energy Balance
Disturbed Physio:
- Hormone deficiency
- Hormone excess
