Chap 25 The Endocrine System Flashcards
What provides slow, lasting communication?
hormones
What are the bodies two communication networks?
nervous system
endocrine system
The endocrine system’s effects are what compared to the nervous system?
slower
longer-lasting
What does the endocrine system consist of?
glands and hormones
What does the endocrine gland consist of?
cells that produce and secrete hormones into the bloodstream, which carries the secretions throughout the body
What is a hormone?
a biochemical that travels in the bloodstream and alters the metabolism of one or more cells
What do hormones interact with?
receptors in target cells
How do hormones carry out their functions?
by binding to receptor proteins in target cells
each hormone is shaped to fit its own receptor protein
Cells express many different hormone receptors and respond to many different hormones?
yes
Hormones can be classified in terms of?
solubility
All hormones travel through the blood to reach…?
their target cells
What are water-soluble hormones called?
peptide hormones
Water-soluble hormones bind to receptor proteins where?
at the outside surface of the target cell
Lipid-soluble hormones can …?
diffuse across the target cell membrane and bind to receptor proteins inside
Water-soluble proteins activate what?
other proteins inside the cell
Where does the cascade reaction begin?
in the target cell when a water-soluble hormone binds to its receptor
What are produced inside the target cell that causes changes in the cell’s activity?
messenger molecules
Give an example of of changes in cel l activity?
muscle contraction
cell division
Lipid-soluble hormones alter…?
gene expression
What are lipid-soluble hormones?
steroid hormones (e.g. estrogen)
What happens to the steroid hormone once inside the cell?
binds to a receptor, forming a complex
What does the hormone/receptor complex bind to?
binds to the DNA inside the nucleus
What does the hormone/receptor do once it binds to DNA in the nucleus?
changes the expression of genes
Hormones are released by?
many endocrine glands
What are the main endocrine glands in vertebrates?
hypothalamus pituitary gland pineal gland thyroid gland parathyroid glands adrenal glands pancreas ovaries (in females) testes (in males)
Together these organs release dozens of hormones that simultaneously what?
every aspect of our lives, from conception through death
What adjusts hormone production?
hypothalamus
The feedback systems coordinated by the hypothalamus respond to what?
current hormone levels, keeping hormones at steady levels in the blood
What releases two hormones produced in the hypothalamus?
posterior pituitary
What are the two hormones that the posterior pituitary releases?
Antidiuretic hormone (ADH or vasopressin)
Oxytocin
What does ADH do?
stimulates cells in the kidneys to return water to the blood stream (rather than eliminating water in urine)
What does oxytocin do?
stimulates ejection of milk from mammary glands and induces contractions of the uterus during child birth
The anterior pituitary does what?
produces and secretes 6 hormones
The rate of pituitary hormone release depends on what?
on which hormones the hypothalamus secretes
What are the 6 hormones produced by the anterior pituitary?
GH Prolactin TSH ACTH FSH, LH Endorphins
Pituitary abnormalities can affect what?
body size (under- or overproduction of growth hormones produces abnormally small or large individuals)
Metabolism is regulated by what?
many hormones
Which glands secrete hormones that influence metabolism?
thyroid gland parathyroid gland adrenal gland pancreas pineal gland
What sets the metabolic pace?
thyroid gland
What are the two thyroid hormones?
thyroxine
triiodothyronine
What do the two thyroid hormones do?
increases the rate of metabolism in target cells of all tissue types
The thyroid also produced what?
calcitonin
What does calcitonin do?
decreases blood calcium levels by increasing calcium deposition in bone cells
What controls calcium levels?
parathyroid glands
What are the parathyroid glands?
four small groups of cells embedded in the back of the thyroid gland
What does the parathyroid hormone (PTH) do?
increases calcium levels in blood and tissue fluid, opposing the activity of calcitonin
What coordinates stress responses?
adrenal glands
What do adrenal glands look like and where are they located?
about the size of walnuts
located atop the kidneys
Each adrenal glands does what?
produces a different set of hormones that play roles in long-term and short-term responses to stress
What regulates short-term stress responses?
the adrenal medulla
The adrenal medulla produces what?
epinephrine
norepinephrine
What do epinephrine and norepinephrine do?
help the body respond to exercise, trauma, fear, excitement
aka the fight or flight response
What are the major responses to epinephrine and norepinephrine?
increase heart rate and blood pressure
dilate airways, so breathing rate increases
increase metabolic rate
slow digestion
What regulates long-term stress response?
the adrenal cortex
What does the adrenal cortex produce?
glucocorticoids
What do glucocorticoids do?
help the body mobilize energy, raise blood pressure, and reduce inflammation
(under chronic stress, these responses become unhealthy)
What regulates blood glucose?
the pancreas
What is the pancreas?
an elongated gland, about the size of a hand, attached to the small intestine
Clusters of cells in the pancreas secrete what?
insulin
glucagon
What do insulin and glucagon do?
regulate the body’s use of glucose
What triggers the pancreas to secrete insulin?
when glucose from food enters the blood stream
What does insulin do?
stimulates cells to absorb glucose from the bloodstream, lowering the blood glucose concentration
What triggers the pancreas to secrete glucagon?
low blood sugar levels
What does glucagon do?
stimulates target cells in the liver to release stored glucose into the bloodstream, keeping the levels steady
What is caused by too much glucose?
diabetes
What is diabetes?
the body’s cells are staving for lack of glucose even though glucose levels in blood and urine are enormous
What happens in type 1 diabetes?
pancreatic cells are destroyed and cannot produce insulin, so patients must inject themselves with it
What happens in type 2 diabetes?
insulin is present but cells become resistant to it. (this form of the disease is impacted by diet and exercise)
What regulates sleep?
the pineal gland
What does the pineal gland secrete?
melatonin
What does melatonin do?
regulates sleep-wake cycles
What initiates/inhibits melatonin?
darkness initiates melatonin synthesis
light inhibits it
Higher levels of melatonin tell the body what?
it is time to sleep
What regulates the ovaries and testes?
FSH and LH
FSH and LH are released by?
anterior pituitary gland
What do FSH and LH trigger in females and where?
the events that lead to the release of an egg cell
at target cells in the ovary
What do FSH and LH trigger in males and where?
stimulates sperm formation and trigger cells to release testosterone
in the testes
Hormones from the ovaries and testes do what?
coordinate reproduction
What hormones are from the ovaries?
progesterone
estrogen
What does progesterone do?
regulates the menstrual cycle and prepares the body for pregnancy
What does estrogen do?
regulates the menstrual cycle and maintains secondary sex characteristic in females
What hormones are from the testes?
testosterone
What does testosterone do?
promotes sperm development and maintains secondary sex characteristics in males
