Lecture 2- Anatomy Of The Endocrine Glands Flashcards
Exocrine glands
Have ducts and secrete onto a surface
Endocrine glands
Do not have ducts and secrete hormones into the bloodstream
What 3 hormones does the thyroid gland secrete?
Thyroxine, triiodothyronine and calcitonin
What is the central connection of the two lobes of the thyroid called?
Isthmus
What is the name of the third lobe that is sometimes present in the thyroid?
Pyramidal glands
Which tracheal rings does the isthmus lie over
T2-4
What cartilage do the lobes of the thyroid gland reach superiorly?
Thyroid cartilage
What hormone is secreted by the parathyroid glands?
PTH (parathyroid hormone)
What controls the secretion of parathyroid hormone?
Blood calcium levels
What are the 3 functions of the parathyroid hormone?
- Stimulates osteoclasts
- Stimulates calcium absorption in the small intestine
- Stimulates calcium reabsorption in the kidneys
What is the name of the structure down which the thyroid gland descends?
Thyroglossal duct
What is the name of the remnant of the thyroglossal duct found on the surface of the tongue?
Foramen cecum
What are the 5 divisions of the pancreas?
- Tail
- Body
- Neck
- Head
- Uncinate process
What are the clusters of endocrine cells in the pancreas?
Islets of Langerhans
What are the 5 main hormones secreted by the pancreas
- Glucagon
- Insulin
- Somatostatin
- Vasoactive intestinal peptide
- Gastrin
What causes the right kidney to lie lower than the left?
The liver
How does breathing affect the position of the kidneys
Diaphragm contracts and the kidneys move down
What are the 2 main hormones produced by the kidneys?
- Renin
2. Erythropoietin
What causes renin release from the kidney?
Low blood pressure/ low blood fluid volume
What hormone does renin act on?
Angiotensinogen
What does angiotensinogen become?
Angiotensin I
Where is angiotensin I converted? And by what?
In the lungs; converted by angiotensin converting enzyme (ACE)
What does ACE convert angiotensin I into?
Angiotensin II
What organ is the target of angiotensin II?
The adrenal glands
What does angiotensin II cause the adrenal glands to release?
Aldosterone
What are the 3 main targets of aldosterone?
- Heart
- Arteries
- Kidneys
What effects does aldosterone have on the arteries?
Vasoconstriction which increases blood pressure
What effect does aldosterone have on the kidneys?
Increased sodium and water retention which increases blood pressure
Which of the adrenal glands is pyramid shaped?
Right
What supplies the hypothalamus?
Primary plexus of the hypophyseal portal system which branches from the superior hypophyseal arteries
What does the anterior hypothalamus control?
Dilation of the skin, blood vessels and sweating
What does the posterior hypothalamus control?
Constriction of skin, blood vessels; inhibition of sweating; shivering
Where is the pituitary gland located?
Hypophyseal fossa, superior to the sphenoid bone
What connects the pituitary to the hypothalamus?
Infundibulum
What supplies the pituitary?
Hypothalamo-hypophyseal portal system
What does the posterior pituitary secrete?
Vasopressin (ADH) and oxytocin
What supplies the posterior pituitary?
Inferior hypophyseal artery
Somatotrophs
Growth hormone (GH)
Thyrotrophs
Thyroid stimulating hormone (TSH)
Gonadotrophs
Follicle stimulating hormone (FSH) Luteinsing hormone (LH)
Lactotrophs
Prolactin (PRL)
Corticotrophs
Adenocorticotropic hormone (ACTH) Melanocyte stimulating hormone (MSH)
What is the exocrine function of the pancreas?
Produces enzymes involved in hydrolysing proteins, fats and carbs- pass into the pancreatic duct and joins bile duct prior to ampulla of vater
What does gastrin do?
Stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility
What does somatostatin do?
Inhibitory hormone which suppresses the release of gastrointestinal hormones
- decreases the rate of gastric emptying
- recused smooth muscle contraction and blood flow within the intestine
- suppresses the release of pancreatic hormones
What does vasoactive intestinal peptide do?
Induces smooth muscle relaxation (stomach, gall bladder)
- stimulates secretion of water into pancreatic juice and bile
- causes inhibition of gastric acid secretion and absorption from the intestinal lumen
What is secreted from the adrenal cortex?
Aldosterone (glomerulosa), cortisol (fasciculata) and androgens (reticularis)
What is secreted by the adrenal medulla?
Epinephrine and norepinephrine (adrenaline and noradrenaline)
