2. Anatomy of the Endocrine Organs Flashcards
what is a GLAND
a group of cells that synthesise and secrete a substance for biological use
what is an EXOCRINE gland
has a DUCT
-usually secretes into a lumen
(excluding sweat glands)
what is an ENDOCRINE gland
secretes directly into BLOOD STREAM
Where is the HYPOTHALAMUS
below thalamus
HYPOTHALAMUS is a collection of…
NUCLEI
( neuro nuclei)
what are NUCLEI of the hypothalamus
small nerve cells are arranged into FUNCTIONAL GROUPS called nuclei.
each nuclei has a SPECIFIC ROLE
(Thermoregulation, osmoregulation,
satiety, ANS control, etc.)
- neuro nucleus is a collection of cell bodies (different to a cellular nucleus)
PITUITARY GLAND is an … gland
ENDOCRINE
PITUITARY GLAND lies in the…
PITUITARY FOSSA of the SKULL
- surrounded by BONE for PROTECTION
PITUITARY GLAND intricately connected to the
HYPOTHALAMUS
- receives instructions from hypothalamus
Posterior Pituitary is a continuation of the hypothalamus
ANTERIOR PITUITARY GLAND has different types of
dedicated cells which synthesise and secrete these hormones
ANTERIOR PITUITARY produces:
- PROLACTIN
- GROWTH HORMONE
- THYROTROPIN
- ADRENOCORTICOTROPIC HORMONE
- GONADOTROPINS eg FSH,LH
action of PROLACTIN from ANTERIOR PITUITARY
acts on MAMMARY GLANDS
results in MILK PRODUCTION
action of GROWTH HORMONE from ANTERIOR PITUITARY
acts on MSK system
results in growth, cell reproduction, regeneration of MSK
action of THYROTROPIN from ANTERIOR PITUITARY
acts on THYROID GLAND
results in T3, T4 production
action of ADRENOCORTICOTROPIN HORMONE from ANTERIOR PITUITARY
Acts on ADRENAL CORTEX (suprarenal glands)
results in CORTISOL production & release
action of GONADOTROPINS eg FSH, LH from ANTERIOR PITUITARY
acts on GONADS - OVARIES, TESTES
results in: LH - triggers ovulation / testosterone release
FSH - regulates development, growth etc.
HYPOTHALAMUS synthesises and secretes … to influence activity of ANTERIOR PITUITARY
RELEASING HORMONES (RH)
- allow release of pituitary hormone
eg, Growth hormone RH - allows release of growth hormone from anterior pituitary,
Prolactin RH
Thyrotropin RH
Gonadotropin RH
Corticotropin RH
INHIBITORY HORMONES (IH)
- inhibit release of pituitary hormones
growth hormone IH (somatostatin)
Prolactin IH (dopamine)
HYPOTHALAMUS synthesises and secretes … to influence activity of ANTERIOR PITUITARY (2)
RELEASING HORMONES (RH)
- allow release of pituitary hormone
eg, Growth hormone RH - allows release of growth hormone from anterior pituitary,
Prolactin RH
Thyrotropin RH
Gonadotropin RH
Corticotropin RH
INHIBITORY HORMONES (IH)
- inhibit release of pituitary hormones
growth hormone IH (somatostatin)
Prolactin IH (dopamine)
does POSTERIOR PITUITARY produce hormones
no
POSTERIOR PITUITARY SECRETES,
does NOT PRODUCE hormones
Where are POSTERIOR PITUITARY hormones PRODUCED
HYPOTHALAMIC NUCLEI
(hypothalamus)
stored in and secreted from posterior pituitary
2 key HORMONES secreted by POSTERIOR PITUITARY
- VASOPRESSIN (aka ADH)
- OXYTOCIN
Function of VASOPRESSIN secreted by POSTERIOR PITUITARY
- regulates OSMOTIC PRESSURE in
BLOOD - stimulates WATER UPTAKE in KIDNEY
Function of OXYTOCIN secreted by POSTERIOR PITUITARY
-helps MILK production and BONDING after birth
how does ANTERIOR PITUITARY receive hormones from HYPOTHALAMUS
HYPOPHYSIAL PORTAL SYSTEM
What does the HYPOTHALAMUS control
ANS (autonomic nervous system)
& ENDOCRINE system
(both are linked)
Parasympathetic - pre-optic and anterior hypothalamic area
Sympathetic - Posterior & lateral nuclei influence
Endocrine - Mostly anterior nuclei influence pituitary activity
Hormones released from THYROID GLAND
T3 (tri-iodothyronine)
T4
(metabolism)
CALCITONIN (calcium homeostasis, lowers calcium levels when high by reducing uptake by gut and preventing breakdown of bone)
name for ‘adam’s apple’
LARYNGEAL PROMINANCE
Thyroid Cartilage forms part of
Larynx
(above thyroid)
THYROID covers which TRACHEAL RINGS
2nd
3rd
4th
Where is the THYROID GLAND DEVELOPED
in the TONGUE
How does development of THYROID GLAND in the tongue start
ENDODERMAL THICKENING
proliferation of cells in tongue so thickening of a region
ENDODERMAL THICKENING burrows through the tongue to form
THYROGLOSSAL DUCT
what happens to THYROGLOSSAL DUCTS
brings thyroid tissue with it, travels down to resting place of thyroid
usually regresses and disappears
what is the FORAMEN CAECUM
small depression on the TONGUE which marks where the THYROID GLAND developed
- after thyroglossal duct disappears
What can you get when Thyroglossal Duct does not disappear
mucus going down it,
can get infected,
form THYROGLOSSAL CYST
what do you get when THYROID GLAND does NOT descend during development and remains sitting in tongue
LINGUAL THYROID
What do you get when tissue is left behind as THYROID descends during development
ACCESSORY TISSUE
PARATHYROID GLANDS are embedded in…
tissue of THYROID GLAND
(posterior)
How many PARATHYROID GLANDS
4
left superior,
left inferior,
right superior,
right inferior
What hormone is released by the PARATHYROID GLAND and what does it do?
PARATHYROID HORMONE
- INCREASES CALCIUM LEVELS in blood if low
antagonist to calcitonin
How does PARATHYROID HORMONE INCREASE CALCIUM LEVELS (3)
- help BREAKDOWN BONE (increase OSTEOCLASTIC activity) this releases calcium into blood
- Increase CALCIUM UPTAKE from GUT
How does PARATHYROID HORMONE INCREASE CALCIUM LEVELS (3)
- help BREAKDOWN BONE (increase OSTEOCLASTIC activity) this releases calcium into blood
- Increase CALCIUM UPTAKE from GUT
- act on KIDNEYS to help REABSORB CALCIUM
4 parts of the PANCREAS
HEAD
NECK
BODY
TAIL
pancreas shares blood supply with
duodenum
Is PANCREAS an exocrine or endocrine gland
BOTH EXOCRINE AND ENDOCRINE
95% EXOCRINE
5% ENDOCRINE
5% of PANCREATIC CELLS that are ENDOCRINE are clustered together in islands and known as…
ISLETS OF LANGERHANS
ISLETS OF LANGERHANS in PANCREAS produce HORMONES involved in sugar/salt homeostasis (5):
- GASTRIN: gastric motility & gastric acid secretion
- GLUCAGON: blood glucose
by causing liver to convert glycogen to glucose (increase blood glucose) - INSULIN: absorption of blood glucose into fat/liver/muscle cells (decrease blood glucose)
- SOMATOSTATIN: release of GI/pancreatic hormones (acts on itself)
& muscle contractions
and rate of gastric emptying - VASOACTIVE INTESTINAL PEPTIDE:
slow down GI tract
smooth muscle relaxation (stomach & GB),
gastric secretions/intestinal absorption
& dilution of bile/pancreatic juice with water
where are the SUPRARENAL GLANDS
sitting on top of the KIDNEYS
both different shapes:
right: pyramidal
left: semi-lunar
What are the 3 layers of the SUPRARENAL GLANDS
-CAPSULE (thick)
- CORTEX (has 3 parts)
- MEDULLA
3 parts of the CORTEX of the SUPRARENAL GLANDS and what HORMONES do they secrete
- GLOMERULOSA zone
produces mineral cortoicoids eg Aldosterone - FASCICULATA zone
produces Glucocorticoids eg Cortisol - RETICULARIS zone
produces sex hormones
What does the MEDULLA of the SUPRARENAL GLANDS produce
ADRENALIN
As well as being an Endocrine organ, the KIDNEYS are mainly part of…
the URINARY SYSTEM
FUNCTIONS of the KIDNEYS (3)
- Excrete WASTE products as URINE
- manage WATER and ELECTROLYTE balance in body
- MAINTAIN ACID-BASE BALANCE of BLOOD
HORMONE released by the KIDNEY and what does it do
ERYTHROPOIETIN (EPO)
- Promotes FORMATION of RED BLOOD CELLS by bone marrow (acts on bone)
- thus INCREASING BLOOD OXYGEN
- higher circulating RBCs elevates blood O2
- EPO can be used to treat anaemia or as
performance enhancing drug
What is the name of the hormone system that begins at the KIDNEY
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
When does the RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS) take place
when there’s a REDUCTION in RENAL BLOOD
(detected by kidneys)
What is the result of the RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
INCREASED BLOOD PRESSURE
what happens in the RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS) when there is a reduction on Renal Blood
- KINDEY secretes RENIN
- inactivated ANGIOTENSINOGEN from LIVER
- ANGIOTENSINOGEN I is converted by ANGIOTENSIN CONVERTING ENZYME (ACE) in the LUNGS to ANGIOTENSINOGEN II
- Angiotensinogen II acts on ADRENAL GLANDS (cortex)
- adrenal glands secrete ALDOSTERONE
-Aldosterone acts on HEART to INCREASE CARDIAC OUTPUT,
ARTERIES for VASOCONSTRICTION
KIDNEY for SODIUM and WATER RETENTION
therefore INCREASED BLOOD PRESSURE
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
what is secreted by kidney
RENIN
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
where does inactive Angiotensinogen come from
LIVER
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
where is Angiotensinogen I converted to Angiotensinogen II and what by?
LUNGS
using ACE - ANGIOTENSIN CONVERTING ENZYME
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
what does angiotensinogen II act on and what does that release?
ADRENAL GLANDS
- ALDOSTERONE
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
how does Aldosterone increase Blood pressure
- acts on HEART to increase cardiac output
- Vasoconstriction of Arteries
- Sodium and Water retention of kidney
