endocrine Flashcards
Endocrine chemical messengers are called
hormones
has 10 major functions that contribute to homeostasis
consists of ductless glands.
endocrine system
include steroids, thyroid hormones, and some fatty acid derivatives.
bind to nuclear receptors located inside the nucleus of the target cell.
lipid soluble hormones
include proteins, peptides, and amino acid derivatives.
circulate freely in the blood
bind to membrane-bound receptors, which are integral membrane proteins.
water soluble hormones
degrade protein and peptide hormones in the blood; the breakdown products are then excreted in the urine.
proteases
exhibited by hormones that are sensitive to circulating blood levels of certain molecules, such as glucose or calcium.
humoral stimulation
cause hormone secretion in direct response to action potentials in neurons, as occurs during stress or exercise.
neural stimuli
Hormones from the hypothalamus that cause the release of other hormones are called
releasing hormones
other hormone secretion is common in the endocrine system.
hormonal stimulation
Hormones from the anterior pituitary that stimulate hormones from other endocrine glands are called
tropic hormones
can inhibit the secretion of hormones.
humoral substance
can prevent hormone secretion.
neural stimuli
prevent hormone release.
inhibiting hormones
prevents further hormone secretion once a set point is achieved.
negative feedback
self-promoting system whereby the stimulation of hormone secretion increases over time.
positive feedback
have portions that allow them to bind to the DNA in the nucleus once the hormone is bound.
cannot respond immediately because it takes time to produce the mRNA and the protein.
nuclear receptors
activates genes, which in turn activate the DNA to produce mRNA.
hormone receptors
increases the synthesis of certain proteins that produce the target cell’s response.
mRNA
activate a cascade of events once the hormone binds.
membrane bound receptors
Some membrane-bound receptors are associated with membrane proteins called
g proteins
act rapidly because they act on already existing enzymes and produce an amplification effect.
second messenger system
connected to the hypothalamus in the brain by the infundibulum. It is divided into anterior and posterior portions.
pituitary
are controlled by hormones that pass through the hypothalamic-pituitary portal system from the hypothalamus.
secretions from the anterior pituitary
secreted from the posterior pituitary are controlled by action potentials carried by axons that pass from the hypothalamus to the posterior pituitary.
secreted by cells in the stomach and intestine help regulate stomach, pancreatic, and liver secretions.
hormones
secretes thyroid hormones, which control the metabolic rate of tissues, and calcitonin, which helps regulate blood Ca+ levels.
thyroid gland
secrete parathyroid hormone, which helps regulate blood Ca?+ levels. Active vitamin D also helps regulate blood Ca?+ levels.
parathyroid glands
secretes primarily epinephrine and some norepinephrine. These hormones help prepare the body for physical activity.
adrenal medulla
reduce inflammation and break down proteins and lipids, making them available as energy sources to other tissues.
Glucocorticoids
help regulate blood Na+ and K+ levels and water volume.
Mineralocorticoids
secreted by the kidneys, helps regulate blood pressure by increasing angiotensin II and aldosterone production.
renin
increase female sexual drive but normally have little effect in males.
adrenal androgens
secretes insulin in response to elevated levels of blood glucose and amino acids.
secretes somatostatin in response to food intake.
pancreas
increases the rate at which many tissues, including adipose tissue, the liver, and skeletal muscles, take up glucose and amino acids
insulin
inhibits insulin and glucagon secretion and gastric tract activity.
somastostatin
secrete testosterone, and the ovaries secrete estrogen and progesterone. These hormones help control reproductive processes.
testes
from the pituitary gland control hormone secretion from the ovaries and testes.
LH and FSH
secretes thymosin, which enhances the function of the immune system.
thymus
secretes melatonin, which may help regulate the onset of puberty by acting on the hypothalamus.
pineal gland
are hormones that have a local effect, produce numerous effects on the body, and play a role in inflammation
prostaglandins
from the right atrium of the heart lowers blood pressure.
ANH
from the kidney stimulates red blood cell production.
Erythropoietin
secretes human chorionic gonadotropin, estrogen, and progesterone, which are essential to the maintenance of pregnancy.
placenta
