The Endocrine System Flashcards
Endocrinology allows the body to communicate and produce signals. It regulates the internal environment by detecting changes. How does it do this?
It uses chemicals, such as proteins/peptides and steroids
What is the name of a constant internal environment?
Homeostasis
Specialised cells/tissues and organs called endocrine glands make up what system?
The endocrine system
What do endocrine glands secrete and where to?
Chemical messengers which are substances, into the internal environment (the blood stream)
Where do chemical messengers released from the endocrine glands act?
Target cells which may be distant from the gland
What are oestrogen, oxytocin, adrenaline, testosterone, insulin and thyroxine examples of?
Hormones
What do the following do: Oestrogen Oxytocin Adrenaline Thyroxine Insulin Testosterone
Oestrogen - controls menstrual cycle/ovulation/secondary sexual cs
Oxytocin - bonding chemical/contractions/lactation
Adrenaline - fight/flight
Thyroxine - metabolic rate/body temp
Insulin - decreases plasma glucose levels
Testosterone - sperm/secondary sexual cs
What are the 3 categories of hormone?
Steroids
Peptides
Amines
What can steroid hormones do?
They are lipid and can go through cell membrane to change chemical in cell
What can peptide hormones do?
Act on cell membrane surface receptor
What do Amine hormones do?
Can go through cell membrane and bind to surface receptors
What type of gland can synthesise/store chemical messengers, have no ducts so need a very rich blood supply and secrete hormones into the blood?
Endocrine Glands
What hormone comes from the parathyroid gland and increases plasma calcium levels?
Parathyroid hormone
What hormone decreases raised calcium levels?
Calcitonin
SO calcitonin DECREASES calcium and parathyroid increases it
What hormone increases sodium released from the adrenal cortex?
Aldosterone
Which hormone increases water reabsorption?
ADH
Which hormone increases the sodium lost at the kidneys and therefor decreases sodium levels in the body?
ANP
Where is the pituitary gland located?
Centre of brain
Where is the thyroid gland located?
Throat
Where are the adrenal glands located?
Above the kidneys
What gland secretes EPO (for red blood cell count production)?
The kidneys
What are the pituitary gland, thryoid gland, adrenal gland, kidneys, testes and ovaries examples of?
Endocrine glands
The hypothalamus releases hormones to the pituitary gland which stimulates the peripheral endocrine gland. All these glands send negative feedback to one another - this is known as regulating the……..
internal environment
What is the name of the area of the brain that forms the walls and floor of the third ventricle, regulates function and is closely related to the pituitary gland?
It also produces the releasing hormones TRH, PRF, PRIF, CRH, GnRH, GHRH and SS.
Hypothalamus
What gland stores the hormones ADH and oxytocin after they have been produced in the hypothalamus and have travelled down axons into the secretory vesicles?
Posterior Pituitary
Which gland is enclosed by a capsule of collagenous connective tissue, is surrounded by thing walled blood vessels and produces and secretes 6 hormones (TSH, PRL, ACTH, LH, FSH and GH)?
Anterior Pituitary
What the following stand for? TSH PRL ACTH LH FSH hGH
Thyroid Stimulating Hormone Prolactin Adrenocorticotrophic Hormone Luteinizing Hormone Follicle Stimulating Hormone Human Growth Hormone
In hormonal cascades, the hypothalamus is the control centre that releases a hormone so that the Anterior Pituitary produces and releases another hormone. This stimulates the endocrine organ to release a hormone that affects the target tissue.
This final hormone then tells the hypo and AP it has had enough. What type of feedback is this?
Negative
The thyroid gland is a butterfly shape in the trachea. What is the middle bit in the thyroid gland that releases hormones directly into the blood stream?
Isthmus
TRH stimulates the release of TSH. This stimulates the breakdown of thyroglobin into T3 and T4. What is this process called?
Thyroid Hormone Regulation
Thyroid hormones cross the cell membrane easily as they are amine. What receptors do they bind to for gene expression and to increase ATP production?
Nucleus, mitochondria and cytoplasm
The functional outcomes of increased metabolic rate (increased HR/resp rate to accommodate increased in metabolic demand, and temp increase) are the function of what hormone?
Thyroid hormone
Lethargy, developmental delay and goitre are effects of what?
Hypothyroidism
Increased BP, heart rate and goitre are effects of what?
Hyperthyroidism
What hormone is produced by the C cells in the thyroid gland?
Calcitonin
What hormone is responsible for lowering calcium and phosphate levels in the blood?
Calcitonin
How does calcitonin lower calcium levels and phosphate levels in the blood?
It reduces the amount released from the bones and it increases the amount excreted by the kidney
What class of hormone binds to membrane receptors?
Peptide
What class of hormone binds to cytoplasmic/nuclear receptors?
Steroid - can get through membrane
What class of hormone is similar to steroid hormones and activates transcription of specific genes?
Amine
What hormone uses a peptide mechanism to stimulate its system?
Adenylate Cyclase
When adenylate cyclase is activated, what acts as a second messenger to open ion channels and activate enzymes?
cAMP
Adrenaline, noradrenaline, ADH, ACTH, FSH, LH, TSH, PTH, calcitonin and glucagon are what type of hormones that activate adenylate cyclase?
Peptide hormones
Steroid hormones are lipid soluble. They diffuse into the cell. Where are the receptors located? (2 locations)
Cytoplasm and nucleus
What class of hormone has direct effects on specific genes? (and produce proteins - enzymes or membrane proteins)
Steroid hormones
What class of hormone are mineralocorticoids (e.g. aldosterone), glucocorticoids (e.g. cortisone) and sex steroids (oestrogen and testosterone) examples of?
Steroid hormones
What hormone increases the osmolarity of the blood by causing sodium reabsorption from the DCT and MCD in the KIDNEY?
Aldosterone (mineralocorticoid) that comes from the adrenal cortex
Are steroid or peptide hormones faster acting?
Peptide are. Steroid has to alter the DNA to switch on genes and then alter cell wall activity
The pancreas uses what kind of hormone?
Peptides
What hormone does the heart tissue secrete?
ANP
What hormone does the kidney tissue secrete?
EPO and renin peptide
What type of hormone does the brain tissue secrete?
Melatonin, BNP
What hormone does the small intestine tissue secrete?
CCK
What type of hormone does the pineal gland tissue secrete?
Melatonin (for circadian rhythms)
What kind of hormone does the parathyroid gland tissue secrete?
Parathyroid hormone that increases calcium
What hormone does the placenta tissue secrete?
Progesterone in pregnancy, HCG?
What hormone does the thymus tissue secrete?
Thymocins
What does paracrine mean?
Effects of hormone are restricted to local environment
What does autocrine mean?
Self stimulation through cellular production of a hormone
High BP, a swollen neck, palpitations, nervousness, high heart rate, insomnia, weight loss, trembling hands and heat intolerance are likely to be side effects of what?
Hyperthyroidism
