Chapter 13 Endocrine System Flashcards
Where do exocrine glands secrete their hormones?
Into capillaries into the bloodstream
Do endocrine glands effect the body intracellularly or extracellularly?
intracellularly
Explain what a target cell is and what it means for hormones in the body.
Hormones will only interact with target cells that are designated to interact with that hormone. The cell will have protein receptors for that hormone.
What happens to hormone receptors on a cell during up-regulation?
More receptors become available to process more of the hormone when the hormone concentration is low and needs to be increased.
What happens to hormone receptors on down-regulation.
Fewer hormone receptors in the cell are available to receive hormones when the hormone levels are high and need to be reduced.
What type of hormone doesn’t enter the bloodstream and only effects nearby target cells?
paracrines
(local hormones)
What type of hormone acts on the same cell it secreted from?
autocrines
What are some intracellular effects to hormones?
- synthesis of new molecules
- changing permeability of the cell membrane
- stimulating transport of a substance into or out of the cell
- altering the rate of metabolic actions
- causing contraction of smooth or cardiac muscle
What are the steps that happen for a hormone to clear the system?
hormone signals turned off
processed by liver and kidney
excreted in bile or urine
What soluble items are hormones made of?
lipids
water
What types of hormones are lipid-soluble?
steroid
thyroid
nitric oxide
What type of hormones are water-soluble?
amine
peptide
protein
eicosanoid
Does the water-soluble or lipid-soluble hormone circulate freely in the plasm?
water-soluble
How do lipid-soluble hormones circulate in the blood?
attached to transport proteins
Are lipid-soluble proteins hydrophobic or hydrophillic?
What does the answer mean for crossing the lipid bylayer of the cell membrane?
hydrophobic
can cross lipid membrane unassisted
What do lipid-soluble hormones bind to after they cross the lipid bilayer?
intracellular receptor
Do water-soluble hormones pass through the lipid byler?
No
What do water-soluble hormones attach to when they reach the cell membrane?
a surface receptor
(extracellular receptor)
Explain the 2nd messenger system
What is a common 2nd messenger?
The water-soluble hormone binds to an extracellular receptor. This is the first messenger.
Then a chemical reaction triggers a second messenger inside the cell
cAMP (cyclic AMP)
How a target cell responds to a hormone is based on:
- the hormone’s concentration in the blood
- the number and type of hormone receptors on the target cell
- influences from other hormones
What is the synergistic effect?
a hormone works more effectively when accompanied by another hormone
what is the antagonistic effect?
hormones oppose the action of another hormone
What are the three different ways hormones are stimulated and hormone secretion is regulated?
(neural stimulus) signals from the nervous system
(humoral stimulus) chemical changes in the blood
(hormonal stimulus) other hormones
What body part controls the pituitary gland?
hypothalamas
What is another name for the pituitary gland?
hypophysis
How does the pituitary gland attach to the hypothalamus?
by the infundibulum
Where does the pituitary gland sit in the skull?
in the sella turcica
What are the two glands of the pituitary (hypophysis) called?
adenohypophysis
neurohyphosysis
Which pituitary gland is the anterior gland?
adenohypophysis
Which pituitary gland is the posterior gland?
neurohypophysis
Is the anterior (adenohypophysis) or posterior (neurohypophysis) larger?
anterior
adenohypophysis
How many hormones does the anterior lobe secrete?
7
How many hormones does the poterior lobe secrete?
Two
How is the anterior pituitary stimulated?
By hormones secreted from the hypothalams
How does the stimulation from the hypothalamas reach the anterior (adenohypophysis) pituitary?
through capillary network called the hypothalamic hypophyseal portal
Describe a hypothalamic pituitary axis
What are the two types of growth hormone?
growth hormone releasing hormone (GHRH)
grown hormone inhibiting hormone (GHIH)
What is insulin like growth factor (IGF)
a small protein hormone that is created by body tissues in response to growth hormone
What is the difference between indirect and direct actions initiated by growth hormone?
indirect is growth promoting
direct is metabolic, anti-insulin effects promoting
What are the 6 hormones released by the anterior (adenohypophsis) pituitary?
human growth hormone (hGH)
thyroid-stimulating hormone (TSH)
follicle-stimulating hormone (FSH)
luteinizing hormone (LH)
prolactin (PRL)
adrenocorticotropic hormone (ACTH)
What does the thyroid-stimulating (TSH) hormone do?
stimulates synthesis and secretion of thyroid hormones by the thyroid gland
what does follicle-stimulating (FSH) hormone do in females and males?
females: development of oocytes and secretion of estrogen by ovaries
males: stimulates testes to produce sperm
What does luteinizing hormone (LH) do in females and males?
females: stimulates secretion of estrogen and progesterone, ovulation
males: stimulates testes produce testosterone
what does the prolactin (PL) hormone do?
milk production by mammary glands
What does the adrenocorticotropic hormone (ACTH) do?
stimulates secretion of glucocorticoids (mainly cortisol) by the adrenal cortex
What two hormones does the posterior (neurohypophysis) pituitary release once produced by the hypothalamas?
oxytocin
ADH (antidiuretic hormone)
What does oxytocin do?
stimulates contracts of smooth muscle for child birth and milk release
What does antidiuretic hormond (ADH) do?
conserves body water by decreasing urine output, through sweating and constricting arterioles
Which pituitary is a neural extension of the hypothalams?
posterior
neurohypophysis
What is the tract that connects the hypothalamas axons with the posterior pituitary?
hypothalamohypophyseal tract
What do osmoreceptors do?
receive information about the status of blood volume an dehydration in the body and delivers it to the hypothalamas
What are the two lobes of the thyroid gland conntected by?
isthmus
What is the path of thyroid stimulating and releasing hormones?
TRH (thyrotropin-releasing hormone) from the hypothalamas stimulates TSH (thyroid-stimulating hormone) from the pituitary, which stimulates the release of thyroid hormones T3 and T4.
What are the cells that secrete thyroid hormone called?
follicular
What do parafollicular (c) cells in the thyroid gland produce?
calcitonin in response to hypercalcemia (too much calcium in the blood)
What type of endocrine gland stimulus is the parafollicular function?
humoral - related directly to blood concentration
what type of endocrine gland stimulus is TSH function?
hormonal
What are the functions of the thyroid hormone?
increase basal metabolic rate (BMR)
maintain body temp
stimulate protein synthesis
increase ATP production
upregulate B receptors
accelerate body growth
Where are the parathyroid glands located?
back of thyroid
How many parathyroid glands are there?
four
two on each lobe of the thyroid
What does the parathyroid release?
PTH
parathyroid hormone and calcitriol in response to high blood calcium levels to help calcium absorption
Where are the adrenal glands located?
on top of each kidney
What is the sympathoadrenal system (adrenal medulla)?
responds to a sympathetic nerve stimulation to release catecholemines (norepinephrine and epinephrine) into the bloodstream
What is the inner portion of the adrenal gland called?
adrenal medulla
what is the outer portion of the adrenal gland called?
adrenal cortex
Name the three layers of the adrenal cortex from outside in
zona glomerulosa
zona fasciculata
zona reticularis
name the pink layer
adrenal cortex
name pink layer
adrenal medulla
name the pink region
what does it do?
zona glomerulosa
secretes hormones called mineralocorticoids to regulate mineral homeostatis for sodium and potassium
name the pink region
what does it do?
zona fasciculata
secretes hormones called clucocorticoids (mainly cortisol) for glucose homeostasis
name the pink region
zona reticularis
releases androgens (DHEA) that is converted to testosterone (male hormones).
in females this gets converted to estrogen and main source of estrogen release after menopause
Explain the path of CRH to ACTH to glucocorticoids
hypothalamas
anterior (adenyhypophysis) pituitary
zona fasciculata in adrenal gland
What is the major mineralocorticoid secreted by the adrenal gland and what is it for?
aldosterone
regulates sodium and potassium homeostasis
water balance
blood pressure
