ENDO-HARC Flashcards
what is a gland?
a group of cells that synthesise and secrete a substance for biological use
what are the 2 types of glands?
- endocrine
- exocrine
what are the differences between the 2 types of glands?
- endocrine-secrete substances directly into blood fluid
- exocrine-secrete substances through a duct often into a lumen
what are the endocrine roles of the hypothalamus?
- links the neurosensory (ANS) system to endocrine system
- site of many converging and diverging neuronal pathways
- uses neurons, blood, CSF to receive info and exert control
- **coordinates secretion of pituitary hormones
what is the hypothalamus comprised of and how is it arranged?
- comprised of small nerve cells
- arranges into functional groups called nuclei
name some of the (anterior) hypothalamic nuclei
- paraventricular*
- supraoptic*
- medial preoptic area
- posterior and anterior preoptic
what is the paraventricular nucleus of the hypothalamus responsible for?
oxytocin release
what is the supraoptic nucleus of the hypothalamus responsible for?
vasopressin release (ADH)
what are the roles of the medial preoptic area of the hypothalamus?
- bladder control
- reduce heart rate and blood pressure
what are the roles of the posterior and anterior preoptic area of the hypothalamus?
- temperature regulation
- thyrotropin inhibition
what is the pituitary gland known as?
master gland
where is the pituitary gland situated?
- lies in the pituitary fossa
- sits in the sella turnica- part of the sphenoid bone
what type of gland its the pituitary gland?
endocrine
what are the key hormones of the anterior pituitary gland?
- prolactin
- growth hormone (GH)
- thyrotropin (TSH)
- andrenocorticotropic hormone (ACTH)
- gonadotropins (LH/FSH)
which system connect the hypothalamus and anterior pituitary gland?
The hypothalamo-hypophyseal portal system-a system of blood vessels in the microcirculation at the base of the brain, connecting the hypothalamus with the anterior pituitary
what are the primary functions of the anterior pituitary gland?
-produces and secretes hormones in response to hypothalamic stimulating hormones
what is the role of prolactin?
- acts on mammary glands
- for milk production
what are the primary functions of the posterior pituitary gland?
-secretes and stores hormones secreted by the hypothalamus
what is the role of thyroid stimulating hormone (TSH)?
- acts on thyroid gland
- T3&T4 production
what is the role of adrenocorticotropic hormone (ACTH)?
- acts on adrenal cortex
- production/ release of cortisol
what are the roles of gonadotropins (LH/ FSH) ?
- acts on ovaries/ testis (gonads)
- LH-triggers ovulation/ testosterone production
- FSH-regulates germ cell development, growth etc.
what are the 2 key hormones secreted by the posterior pituitary gland?
- vasopressin-ADH
- oxytocin
what are the roles of vasopressin?
- stimulates water uptake in kidney
- release regulated by osmotic pressure of blood
what are the roles of oxytocin?
-helps milk production and bonding after birth
which hypothalamic areas influence parasympathetic activity and give examples of how?
- pre-optic and anterior hypothalamic areas
- increase salivation/ lower HR and BP
which hypothalamic areas influence sympathetic activity and give examples of how?
- posterior and lateral nuclei
- increase HR & BP, vasoconstriction
which hypothalamic nuclei mostly influences pituitary activity?
anterior
what are the functions of the kidney?
- excrete waste products of metabolism as urine
- manage water and electrolyte balance in body
- maintain acid-base balance
- many endocrine roles-secretes many hormones
- —>erythropoietin
what are the 2 sections of the kidney and what do they secrete?
- medulla-secretes catecholamines- adrenaline/ noradrenalin
- cortex-secretes cortisol/ aldosterone
which arteries supply the thyroid gland?
The superior thyroid artery (STA) arising from the external carotid artery (ECA), and the inferior thyroid artery (ITA) branching from the thyrocervical trunk
which veins drain the thyroid gland?
superior thyroid veins and middle thyroid veins drain into the internal jugular vein
what are the 2 major hormones produced by the thyroid?
- T4-thyroxine-secreted more by gland
- T3-tri-iodothyronine- more active form of hormone
what is the role of calcitonin?
calcium homeostasis
-antagonist to parathyroid
how does calcitonin work?
- prevents Ca2+ being absorbed by gut
- also prevents/ slows bone breakdown
where does the thyroid gland develop?
in the tongue
what does the parathyroid gland produce?
parathyroid hormone PTH
how does the parathyroid hormone act?
- acts as antagonist to calcitonin
- id blood Ca2+ is low, parathyroid gland detects this and releases PTH
is the pancreas an endocrine or exocrine organ?
both
what % of pancreatic cells are endocrine?
10%
what are the pancreatic endocrine cells called?
Islets of Langerhan’s
what does the 3 and 4 represent in T3 and T4?
the number of iodine molecules
which hormone can be given to someone suffering from hypothyroidism?
T4
which hormone can be given to someone suffering from hypothyroidism?
T4-absorbed into the gut more than T3
how does the thyroid gland develop?
embryology=
- at week 4 a region of the tongue becomes thicker-due to cell proliferation-forms endodermal thickening
- endodermal thickening will burrow through the tongue and form the thyroglossal duct-brings the thyroid tissue with it
- travels anterior to the hyoid bone and thyroid cartilage before reaching its final resting place
- duct then regresses
what is the shape of the thyroid gland?
butterfly/ H-shaped
what are the functions of PTH?
- increases osteoclastic activity-bone breakdown-release Calcium into bloodstream
- increases Ca take up from the gut
- acts on kidneys to absorb calcium
which hormones are produced by the pancreas?
- gastrin
- glucagon*
- insulin
- somatostatin
- vasoactive intestinal peptide
what does gastrin hormone do?
helps the pancreas produce enzymes for digestion and helps the liver produce bile
what are the roles of PTH?
- increases osteoclastic activity (break down bone)-release Ca into bloodstream
- increase Ca uptake form gut
- act on kidneys to reabsorb any Ca
what are the 4 different sections of the pancreas?
head, neck, body, tail
what does glucagon do?
counteracts the actions of insulin by stimulating hepatic glucose production-glycogenolysis and gluconeogenesis and thereby increases blood glucose levels
what does insulin do?
allows excess glucose to be stored as glycogen in liver and muscles-lowering blood glucose
what does somatostatin do?
release of GI/ pancreatic hormones and muscle contractions-rate of gastric emptying
what is the vasoactive intestinal peptide involved in?
- smooth muscle relaxation, -gastric secretions
- dilution of bile pancreatic juice with water
how is the posterior pituitary connected to the hypothalamus?
hypothalamo-hypophseal tract-neural connection
where is the the hypothalamus situated?
medial portion of brain
how is the pituitary gland connected to the hypothalamus?
infundibulum/ pituitary stalk
what is the posterior pituitary largely comprised of?
composed largely of axons of hypothalamic neurones which extend downward as large bundle behind anterior pituitary
what are the storage cells of the posterior pituitary gland called?
neurohypophysis
what are the secretory cells of the anterior pituitary called?
adenohypophysis
what artery supplies the pituitary gland?
superior hypophyseal artery
which veins drain the pituitary gland?
hypophyseal veins
where is the pancreas located on the body?
- located in upper left quadrant
- posterior to stomach and anterior to kidneys
which part of the pancreas is intraperitoneal?
tail
head, neck, body=retroperitoneal
what is the shape of the left adrenal gland?
semi-lunar
what is the shape of the right adrenal gland?
pyramidal
are the adrenal glands intraperitoneal or retroperitoneal?
retroperitoneal
how are the cells in the zona glomerulosa arranged?
-cells arranged in spherical clusters and arched columns
how are cells in the zona fasciculata arranged?
cells arranged in straight columns
how are cells of the zona reticularis arranged?
cells arranged in branching cords
what are the 3 layers of the adrenal medulla?
- zona glomerulosa (outermost)
- zona fasciculata
- zona reticularis (innermost)
which arteries supply the adrenal glands?
- superior suprarenal arteries- branch off inferior phrenic arteries
- middle suprarenal arteries-branch off aorta
- inferior suprarenal arteries-branch off renal arteries
describe the venous drainage of the adrenal glands.
- right adrenal vein drains into inferior vena cava
- left adrenal vein drains into left renal vein which drains into inferior vena cava
what is the structure of the thyroid gland?
- consists of 2 lateral lobes and a central isthmus-overlying tracheal rings 2-4
- lateral lobes of thyroid gland extend superiorly to touch thyroid cartilage
- pyramidal lobe is sometimes present in isthmus
what is the remnant of the thyroglossal duct called?
foramen caecum
what is the formal name for the structure that makes up the Adam’s apple?
thyroid cartilage
-flatter in women
how many parathyroid glands are there and where are they found?
4 small glands found on posterior side of thyroid gland
