Endocrine system - Hints 2
From the doc posted by Ida
Terms in this set (62)
Where are glucocorticoids produces?
Acidophilic cells of zona fasciculata of the adrenal cortex
Development of glucocorticoid producing cells?
Cells of distas adenohypophysis?
Acidophils, basophils, chromophobe cells
Products from acidophils?
Somatotropin (a-cells), and prolactin (e-cells)
Products from basophils?
ACTH (b1), TSH (b2), FSH/LH (o)
Products from chromophobe cells?
Characteristics of steroid producing cells?
No secretory vesicles
Size of ADH?
9 amino acids
Cells producing ADH?
Magnocellular neurosecretory cells in PVN and SON
When do insulin production start?
Glucose effects on b-cells calcium concentration?
Increases. Glucose increaeses ATP, which block K-pumps. More excitable membrane, more calcium influx due to opening of voltage gated calcium channels
Cleavage of proinsulin?
Proteases in GA cleaves proinsulin into mature insuline and a C-peptide.
Folding of insulin?
E.R. Oxidation also happens here (disulfide bonds)
Glucose and TAG metabolism in adipocytes?
FA and TAG are synthesised in adipose tissue
Glucose is produced from glycerol in the liver
Storage of peptides and catecholamines?
How active is a preprohormone?
Still contains all translated AAs, so not biologically active (may be exceptions)
Steroid hormone receptors?
Ligand and receptor form a heterodimer. Translocates to the nucleus and the two heterodimers form a homodimer (of two heterodimers). This homodimer is the transcription factor.
What is a heat shock protein?
A protein bound to the receptor before the ligand binds. Prevents translocation to the nucleus.
Transport of thyroid hormones?
70% bound to TBG
10-15% bound to TTG
15-20% bound to albumin
0.03% is free T4
0.3% is free T3
Binds to its receptor. The receptor complex binds to a retinoic acid receptor (withour ligand). This is the transcription factor
Statin concentration in pituitary stalk?
Probably higher that in peripheral blood because it is supplied from superior hypophyseal artery, which is the start of the portal system of hypothalamus
Regulation of secretion from hypothalamus?
Noradrenalin stimulates: GHRH, CRH, TRH, ADH
Dopamin inhibits: Prolactin secretion and GnRH.
Dopamin and Ach stimulates CRH
Serotonin stimulates release of GHRH
Transport through pituitary stalk?
ADH and OXY are bound to neurophysins and transported in vesicles along microtubules
Control of ACTH release?
CRH, which is released from PVN of hypothalamus
Main circadian pacemaker?
Epiphysis by secretion of melatonin in response to light
Circadian release of ACTH?
Early moring. Peak around 8am
Main trigger for aldosterone secretion?
Extracellular potassion. AGII and ACTH also participates
Conversion enzyme T4 to T3?
Typical hormone levels in patients with hyperthyroidism?
Elevated T3 and T4.
Decreased TSH and TRH due to negative feedback
PTH effects on kidney and bones?
Increased uptake of calcium and wasting of potassium
Increased vit D synthesis
Apocrine sweat glands?
Secrete into infundibular portion of hair cells
Oily fluid with protein, lipids and steroids
Odorless befor microbial activity
Location of hypophysis?
In the hypophyseal fossa of the sphenoid bone
Blood supply of thyroid glad
Superior thyroid a. from ext carotid
Inferior thyroid a. from thyrocervical
Thyroid ima a. from subclavian
Location of parathyroid glands?
Dorsally on each of the four "wings" of the thyroid gland
Secretes pancreatic peptides
2-5% of the cells of Islets of Langerhans
Content of the posterior pituitary?
Axons from hypothalamus
Size/shape of thyroid follicular cells?
Origin of parafollicular cells?
What is secreted by C-cells?
Production site of mineralocorticoids?
Zona glomerulosa of adrenal cortex
Origin of melanocytes?
Location of melanocytes in meninges?
Only in leptomeninges (arachnoid and pia mater)
Origin of hypophysis?
Anterior: Rathkes pouch
Origin of thyroid gland?
Endoderm of primitive pharynx
Starts developing at day 24
Descends through caecum (which closes before birth)
GIP and GLP-1?
GIP from K-cells
GLP-1 from L-cells
Natural antidiabetics; lowers glucose levels
Effects of GH?
Promotes protein synthase
Increases blood glucose
Catecholamines effect on insulin?
Insulin is strongly inhibited. The body needs glucose when catecholamines are released
Adrenaline levels during exercise?
Increase. A stress response
Progesterone levels during ovulation?
About to increase. After ovulation, more progesterone is produces. Estrogen triggers LH release, which triggers ovulation
Insulin sensitivity from adipokines?
Adiponectin and leptin reverses insulin resistance
IL-6, TNF-a, and FA desensitizes tissue to insulin
Transport of peptides in blood?
Most are free. ILGF binds to plasmaproteins
Transport of catecholamines in blood?
50% are protein bound
Duration of ultradian rhythms?
Less that 24 hours
Leptin vs Ghrelin?
Leptin is the satiety hormone
Ghrelin is the hunger hormone
How is adenylyl cyclase activated?
Alpha subunit of Gs
Results of long term overstimulation of receptors?
What is a short loop?
Hormones from pituitary working on the hypothalamus
How is prolactin secretion inhibited?
Dopamine secreted from the arcuate nucleus
Symptoms of Cushing syndrome?
High levels ofcorticosteroids
What is stress?
Non-specific response of the body to a situation it perceives as threatening to the homeostasis
Progesterone production during pregnancy?
Corpus luteum until week 10
Placenta from week 10
Pacemaker of the menstrual cycle?
LH, FSH, progesterone, estrogen (estradiol)
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