Endocrinology Basics (y1/2) Flashcards
Where do lipid soluble hormones bind?
receptors in cytoplasm or nucleus
Where do water soluble hormones bind?
Receptors on cell surface
Where are the exocrine cells of the pancreas located?
Acini (clusters)
Where are the endocrine cells of the panrcreas located?
Amongst the acini - islets of langerhans
What are the 4 cell types of the pancreatic islet and what do they each secrete?
Alpha - glucagon
Beta - insulin
Delta - somatostatin
F cell - pancreatic polypeptide
What are the 3 targets of insulin?
Liver
Muscle
Adipose Tissue
Which 3 organs are NOT insulin dependent?
Brain (although NEEDS glucose)
Kidney
Intestine
What action does glucose have at a molecular level?
Inserts GLUT 4 transporters into cell wall.
What action does glucose have at a cellular level?
inc glucose metabolism
inc glycogen, protein and triglyceride synthesis
What action does glucose have at a tissue level?
decrease plasma glucose by:
inc transport into cells
OR
inc metabolic use
Apart from inc blood glucose, what 3 things may increase insulin secretion?
Inc plasma AA’s
Anticipatory release of GI hormones
Inc Parasympathetic activity during/post meal
What is the role of glucagon at a tissue level?
Glycogenolysis and Gluconeogenesis
Ketogenesis
Which tissue is the target of glucagon?
Liver
What is glucagon released in response to?
Dec plasma glucose
Inc plasma AA’s
Parasympathetic & SYMP (stress) activity
What is the role of somatostatin?
Decrease Growth Hormone
Stop insulin/glucagon release
What is the role of Pancreatic Polypeptide?
Unknown! increases after meals
What is Type 1 DM?
Inadequate insulin secretion
What is Type 2 DM?
Abnormal target cell response to insulin
What are the signs of DM?
Hyperglycaemia
Weight loss - low protein synth and low glucose cause muscle breakdown
PU/PD
ketoacidosis
What does the pituitary consist of?
2 fused glands:
AP: endocrine
PP: neural extension
What is secreted by the Posterior Pituitary?
Oxytocin
ADH
Where are ADH and oxytocin produced?
Hypothalamus
How do the hypothalamic hormones reach the AP?
Portal Capillary System
How do the hypothalamic hormones reach the PP?
In vesicles down neuron cell body
What are the 6 hormones secreted by the AP?
FLAT PiG:
FSH LH ACTH TSH Prolactin GH
What are the 3 releasing hormones that affect the AP?
TRH
CRH
GnRH
Where is thyroid hormone produced?
Thryoid Gland:
Follicular cells and T3/T4 assembled in colloid
How long does the supply of T3/T4 last in the thyroid?
2-3m
What is the main hormonal product of the thyroid gland?
T4
Which thyroid hormone is the most biologically active?
T3
Where is T3 produced?
Thyroid Gland
AND converted from T4 in peripheral tissues?
What is the role of the thyroid hormones?
Increase BMR Enhanced CHO utilisation Growth & development CV stimulant Promotes milk production
On which two organs does negative feedback from the thyroid occur?
AP
Hypothalamus
What are the 4 major signs of hyperthyroidism?
inc appetite and WL
Hyperthermia
Inc HR
Excitable
What are the 5 major signs of hypothyroidism?
Weight gain but no inc appetite Hypothermia Lethargy/Poor exercise tolerance Dec HR Dullness
Where is the adrenal gland in relation to the kidney?
Craniomedially
What are the 4 layers of the adrenal gland and what do they produce?
Cortex:
Zona glomerulosa: mineralocorticoid
Zona fasiculata: glucocorticoid
Zona Reticularis: androgens
Medulla: Adrenaline/Noradrenaline