Flashcards in Endocrine Deck (36):
Humoral Hormone (mechanism of hormone release):
in response to changing levels of ions or nutrients in the blood
Neural (mechanism of hormone release)
stimulation by nerves
Hormonal (mechanism of hormone release)
stimulation received from other hormones
The hypothalamus controls....?
secretion of hormones which also control the secretion of hormones by the thyroid gland, the adrenal cortex and gonads: in this way the brain controls these endocrine glands.
What are the five releasing hormones of the hypothalamus?
1. TRH (thyroid releasing hormone) -----turns on* TSH
2.CRH (corticotropin releasing hormone) --turns on ACTH
3.GnRH (gonadotropin releasing hormone) ---turns on FSH and LH
4. PRF (prolactin releasing hormone) -----turns on PRL
5. GHRH (growth hormone releasing hormone) ----turns on GH
What are the two inhibiting hormones of the hypothalamus?
1. PIF (prolactin inhibiting factor) -----turns off PRL
2. GIH (growth hormone) inhibiting hormone ---turns off GIH
Name the 7 hormones that anterior pituitary secretes.
1. TSH (Thyroid-stimulating hormone)
2. ACTH (Adrenocorticotrophic hormone)
3. FSH (Follicle-stimulating hormone)
4. LH (Luteinising hormone)
5. GH (Growth hormone)
6. PRL (Prolactin)
7. MSH (Melanocyte-stimulating hormone)
* The first 4 hormones are tropic.
Name the 2 hormones that posterior pituitary secretes.
8. ADH (antidiuretic hormone), or vasopressin
Thyroid Stimulating Hormone (TSH)
TSH stimulates the thyroid to produce thyroid hormone
Adrenocorticotropin hormone (ACTH)
ACTH stimulates the adrenal cortex to produce corticosteroids: aldosterone and cortisol
FSH (follicle stimulating hormone)
FSH stimulates follicle growth and ovarian estrogen production; stimulates sperm production and androgen-binding protein
LH (Luteinising hormone)
LH has a role in ovulation and the growth of the corpus luteum; stimulates androgen secretion by interstitial cells in testes
GH (Growth hormone)
GH stimulates growth of skeletal epiphyseal plates and body to synthesize protein
PRL stimulates mammary glands in breast to make milk
melanocyte stimulating hormone (MSH)
MSH stimulates melanocytes; may increase mental alertness
Antidiuretic Hormone (ADH)
ADH (antidiuretic hormone AKA vasopressin) stimulates the kidneys to reclaim more water from the urine, raises blood pressure
Oxytocin prompts contraction of smooth muscle in reproductive tracts, in females initiating labor and ejection of milk from breasts
Posterior pituitary does not produce any hormones it only releases hormones that are made in the hypothalamus. Oxytocin and ADH are stored in the posterior pituitary.
Cells in the anterior pituitary will signal to make another hormone and that hormone will be send to the blood supply.
Cellular action mechanism
Hydrophilic (Lipophobic) – must bind to receptors on membrane’s ECF surface
Most work via cAMP messenger system
Cannot diffuse across cell membranes
Can move through blood and ECF without receptor
Increases the basal metabolic rate.
Affects many target cells throughout the body; some effects are
When calcium is too high you secrete
When calcium levels is too low you secret
Secreted by adrenal cortex in response to a decline in either blood volume or blood pressure
Helps the body deal with stressful situations within minutes. you don't want to make too much cortisol for a long period of time.
Physical: trauma, surgery, exercise
Psychological: anxiety, depression, crowding
Physiological: fasting, hypoglycemia, fever, infection
What happens when you are stressed out?
Hypothalamus releases Corticotropin-Releasing Hormone, CRH binds to anterior pituitary makes ACTH to adrenal cortex. Adrenal cortex can make a negative feedback of cortisol but if you are so stressed out the negative feedback might not work.
responsible of making melatonin
the pineal gland
What are hormones?
Chemical messengers secreted by specialized cells.
Down-regulation vs. desensitization of hormones
Down regulation is slower as cell needs to remove receptors from membrane.
Desensitization is quicker as a binding agent can deactivate the receptor.
How do hormones get from point A to B?
***Travel in blood***
-May require water soluble (protein) transport mechanism if hormone is lipid soluble
-Hydrophilic hormones act by binding to receptor on target cells
The three types of hormones?
peptide/protein, steroid and amino acid base hormones
Cellular action mechanism
-Hydrophilic (Lipophobic) – must bind to receptors on membrane’s ECF surface
-Most work via cAMP messenger system
-Cannot diffuse across cell membranes
-Can move through blood and ECF without receptor
-Hydrophobic (Lipophilic) – creates problems
-No storage: Production is on an “as needed” basis
-Produced in the adrenal cortex, gonads and placenta
-Require protein transports in blood
Steroid Hormone regulation
-Negative feedback loop – increased transcription factors cause a decrease in production
-Phosphorylation – may stop transcription
-Ligand binding to transcription factors or cofactors that regulate the transcription factors
Amino Acid Hormones
Amino acid derived hormones may be derived
-T3 & T4
-Epinephrine & norepinephrine
Amino acid derived hormones may be derived from tryptophan