endocrine system Flashcards
what is homeostasis
maintenance of a constant internal environment through the use of chemicals (proteins/peptides + steroids)
what is the endocrine system made up of
composed of specialised cells/tissues and organs - endocrine glands
what are the 3 types of hormones and identify 2 of each
steroid - testosterone + oestrogen
peptide - oxytocin + insulin
amine - adrenaline + thyroxine (regulates basal rate of metabolism)
parathyroid, where is it from and what does it do
secreted by the chief cells of the parathyroid glands - increases calcium levels when they get low by causing the release of calcium from bones
calcitonin, where is it from and what does it do
produced by C cells of the thyroid, Calcitonin lowers the concentration of calcium in the blood
aldosterone, where is it from and what does it do
(opposite to ANP) secreted from the adrenal glands, acts on the kidney to conservation of sodium (increases sodium concentration) and regulate blood pressure
ADH, where is it from and what does it do
A hormone produced in the hypothalamus and secreted by the posterior pituitary gland. ADH stimulates reabsorption of water through the distal convoluted tubules and collecting ducts of the kidney, resulting in less water being excreted in the urine, thus conserving water.
ANP, where is it from and what does it do
(opposite to aldosterone) decreases plasma sodium levels. Atrial natriuretic peptide is released from the heart muscle cells, ANP acts to reduce the water, sodium and adipose loads on the circulatory system, thereby reducing blood pressure
what do endocrine glands do
synthesise/store chemical messengers
no ducts very rich blood supply
hormones secreted into blood
what controls homeostasis
negative feedback mechanisms
where would you find endocrine glands
hypothalamus pituitary gland thyroid gland adrenal gland ovaries/testicles
how many hormones does the anterior pituitary gland secrete and what are they
6 hormones
TSH - thyroid stimulating hormone (stimulates the thyroid gland to produce thyroxine (T4), and triiodothyronine (T3) which stimulates the metabolism of almost every tissue in the body)
PRL - Prolactin,(It stimulates the mammary glands to produce milk - lactation)
ACTH - Adrenocorticotropic hormone ( Its principal effects are increased production and release of corticosteroids)
LH - Leutenising hormone In females, an acute rise of LH triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone it stimulates Leydig cell production of testosterone
FSH - Folicle stimulating hormone (FSH regulates the development, growth, pubertal maturation and reproductive processes of the body. FSH and luteinizing hormone (LH) act synergistically in reproduction)
HGH/GH - Human growth hormone (stimulates cell growth, reproduction and regeneration)
what is the structure/function of the pituitary gland
It is located next to the hypothalamus in the brain. It is enclosed by a capsule of collagenous connective tissue and surrounded by thin walled blood vessels. secretes 6 hormones
what is the structure/function of the hypothalamus
It is an area of the brain - forms walls and floor of the 3rd ventricle. It is closely related to the pituitary gland and has a regulating function. Produces hormones (releasing hormones.
what are the 7 hormones produced by the hypothalamus
TRH - Thyrotropin-releasing hormone (stimulates the release of TSH (thyroid-stimulating hormone) and prolactin from the anterior pituitary
PRF - prolactin realeasing factor (stimulates prolactin release from anterior pituitary)
PRIF/PIF - Prolactin inhibiting factor (Inhibits the release of prolactin)
CRH - corticotropin-releasing hormone (stimulates both the synthesis and the secretion of adrenocorticotropic hormone - ACTH)
GnRH - Gonadotrophin releasing hormone (stimulates the pituitary gland to produce luteinizing hormone - LH)
GHRH & SS - growth hormone-releasing hormone (stimulates anterior pituitary to produce growth hormone) & somatostatin - aka growth hormone inhibiting hormone (inhibits release of growth hormone from anterior pituitary)
posterior pituitary, what 2 hormones does it produce?
( 2 p’s 2 hormones!)
ADH - Anti-diuretic hormone aka vassopressin ( Vasopressin regulates the body’s retention of water by acting to increase water reabsorption in the collecting ducts of the kidney nephron. It also increases peripheral vascular resistance, which in turn increases arterial blood pressure)
Oxytocin -
what two systems maintain homeostasis
endocrine - slow but more precise
autonomic nervous system - quick
what does the hypothalamus do
controls the pituitary and has an indirect affect on other glands
how is the anterior and posterior pituitary supplied with arterial blood
anterior - from internal carotid artery indirectly from hypothalamus (pituitary portal system which also transports releasing and inhibiting hormones)
posterior - from internal carotid artery directly
how is pituitary venously drained
drained from both lobes into venous sinuses between layers of dura mater
draw table of hormone…where from, (and cells produced by) hormone, stimulated/regulated by what, what does it act on, what does it do, other e.g iodine essential for T4 , T3 production
draw it
when looking at a diagram of the pituitary where does the optic ciasm (big lump) lie
over the anterior pituitary
where is the thyroid gland situated, describe it, what 3 hormones does it release
in the neck (trachea) made up of 2 lobes, butterfly dhaped, with very good blood supply - T3 T4 and Calcitonin
draw thyroid gland
draw it - NOT PRINTED!
where is calcitonin released from and what does it do?
released from c cells of thyroid gland. Acts on bone cells and kidneys to reduce blood calcium
what are the symptoms of hyperthyroidism (increased T3 and T4 production
increased basal metabolic rate
BP/Heart rate increased
goitre
what are the symptoms of hypothyroidism (decreased T3 and T4 production
decreased basal metabolic rate
lethargy, developmental delay, goitre
which cells produce T3 and T4
follicular cells of thyroid gland stimulated by TSH
T4 is converted to T3 at target tissue
is there more T3 or T4 amines
T3 - 10%
T4 - 90%
what do T3 and T4 do
metabolism control - temp, heart rate
what is a goitre
enlargement of the thyroid gland
what is adenylate cyclase
an enzyme with key regulatory roles in essentially all cells
what is the mech of a for peptide hormones?
peptide hormones use cAMP to act as a 2nd messenger.
Secondary messengers are therefore one of the initiating components of intracellular signal transduction cascades.’ 2nd messengers opens ion channels and active enzymes)
adrenaline/noradrenaline, ADH, ACTH, FSH, LH, TSH, PTH, Calcitonin, glucagon
how do steroids work on a cellular level, what are the 3 types of steroid hormones and give an example
They alter DNA - switching on or off genes mineralocorticoid (aldosterone) glucocorticoids (cortisone) sex steroids (testosterone)
what is the mech of action for steroid hormones
they diffuse into cell as lipid soluble
what is the mech of action for amines (ie thyroid hormones)
similar to steroid hormones, they both slip easily through the cell membrane (binds to mitrochondria - increases ATP)
what is the hormone secreted from the heart
Atreal/brain natriuretic peptide ANP/BNP - (a powerful vasodilator, and a protein (polypeptide) hormone secreted by heart muscle cells in response to high blood volume)
what is the hormone secreted from the kidney
EPO Erythropoietin - controls red blood cell production
Renin - actually an enzyme which regulates the body’s mean arterial blood pressure.
what is the hormone secreted from the small intestine
CCK - Cholecystokinin (stimulates digestive enzymes from the pancreas and bile from the gallbladder)
Secretin - Secretin is a hormone that regulates water homeostasis throughout the body, and influences the environment of the duodenum by regulating secretions in the stomach and pancreas.
what is the hormone secreted from the pineal gland (endocrine gland in the vertebrate brain)
Melatonin - helps regulate other hormones and maintains the body’s circadian rhythm
what is the hormone secreted from the parathyroid
PTH - Parathyroid hormone (is secreted by the chief cells of the parathyroid glands to increase the concentration of calcium in the blood) opposite to calcitonin
what is the hormone secreted from the placenta
Progesterone - steroid hormone involved in the female menstrual cycle, pregnancy
what is the hormone secreted from the thymus (specialized organ of the immune system)
Thymosin - stimulates development of T cells a type of lymphocyte (white blood cell) that play a central role in cell-mediated immunity.
what is the hormone secreted from the pancreas
insulin - secreted by beta cells in the pancreas to reduce blood glucose
glucagon - produced by alpha cells of the pancreas, raises blood glucose levels
what does paracrine mean
effects of hormone are restricted to local environment
what does autocrine mean
self stimulation through cellular production of a hormone
draw functional classification diagram on front page of endocrine versus the nervous system
draw it
give 4 facts about the endocrine system
utilises endocrine glands
secretes hormones
blood as travel medium
utilises receptors
what is the difference between endocrine and exocrine
Exocrine glands are glands that secrete their products through the ducts, and discharge it into the external environment, to organs or the outside the body. Exocrine glands differ from endocrine glands, because they have ducts that deliver the products in the superficial part of the body, such as the skin, or in the inner part where they are necessary, such as the pancreatic juice that is carried into the intestine to aid digestion.
give 5 facts about the nervous system
1) nerves supply organs and tissues in distinct anatomically difined pathways
2) electrical impulses propagate as action potentials (changes in Na and K permeability)
3) Act on limited number of cells
4) high speed transmission
5) point to point transmission
what is an androgen and where is it produced
sex/steroid hormone e.g testosterone
in the adrenal cortex like all steroids
give an example of a glucocorticoid (1 of the 3 types of steroid hormone along with mineralocorticoid and androgens) where is it produced?
cortisol (hydrocortisone) .
regulate metabolism in response to stress
produced by the adrenal cortex like all steroid hormones
give an example of a mineralocorticoid (1 one the 3 types of steroid hormone along with glucocorticoid and androgens) where is it produced
aldosterone maintenance of water and electrolyte balance
produced by the adrenal cortex like all steroids
Recall the renin-angiotensin-aldosterone system
the enzyme renin converts angiotensinogen to angiotensin 1, ACE (angiotensin converting enzyme) angiotensin 1 to angiotensin 2 which stimulates the secretion of aldosterone
are the pre-ganglionic nerves short or long in the sympathetic nervous system
pre - ganglionic: short
post - ganglionic: long
are the pre-ganglionic nerves short or long in the parasympathetic nervous system
pre-ganglionic: long
post -ganglionic: short
in the sympathetic nervous system, what’s the neurotransmitter between pre and post ganglion
pre - acetylcholine
post - noradrenalin
in the parasympathetic nervous system, what’s the neurotransmitter between pre and post ganglion
pre - acetylcholine
post - acetylcholine
in the sympathetic nervous system where do the nerves exit the CNS
thoracic and lumber segments of the spine
in the parasympathetic nervous system where do the nerves exit the CNS
brain stem (crainial nerves III, VII, IX, & X) and the sacral region of the spine
what does the adrenal medulla produce
secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.
what are the differences between the effects of the endocrine and nervous systems
Endocrine is: Slower response Effects more long lasting- hours/days Speed dependant on blood flow Distance to effector and vascular supply
whereas….
Nervous is:
Rapid response to stimuli
Short lived (10 msec
the neurotransmitter adrenaline/noradrenaline effects which receptors and what is the effect
Alpha and Beta receptors
Alpha 1 - peripheral vascular smooth muscle (vasoconstriction)
Alpha 2 - presynaptic membrane (inhibit transmitter release)
Beta 1 - heart (increase force of contraction, increase HR)
Beta 2 - brochiole smooth muscle/vascular smooth muscle (dilation)
Beta 3 - adipose tissue (lipolysis - break down of lipids)
the neurotransmitter Acetylcholine can have an effect on which receptors
cholinergic receptors (either muscarinic or nicotinic - the difference between the two is their mode of action)
Which hormones plays an important role in the endocrine and nervous system?
adrenaline/noradrenaline
