113 terms

Endocrine System

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Calcitonin is secreted by which cells?
C Cells in the thyroid
The zona fasciculata of the adrenal cortex produces what steroid hormone?
Cortisol
Cortisol
helps deal with stress by increasing plasma glucose, amino acids, and fatty acids
The sympathetic nervous system directly stimulates which of the following amine hormones?
epinephrine from the adrenal medulla
What hormone causes the loss of sodium and water, thus lowering blood pressure?
atrial natriuretic peptide (ANP)
q
ANP
is synthesized in the atrium and increases excretion of sodium and water from the kidneys
Melatonin
helps coordinate body activities with the light-dark cycle. Released from the pineal gland.
What hormone promoes glycogen synthesis in liver and muscle
insulin
First Messenger
Any hormone, has to bind to a receptor at a target cell in order to cause an intracellular response
Second Messenger Pathway
ATP is converted in cAMP, which causes the intracellular reactions. The first messenger binds to the protein receptor. The receptor activates the G protein, which stars the conversion of ATP into cAMP
Hormones
chemical messengers that are released by cells and transported in the bloodstream to alter the activities of specific cells in other tissues.
Paracrine Communication
factors similar to hormones, used for the regulation of cell and organ activities, make local hormones, made by cells that affect surrounding cells, many cells produce paracrine factors.
In Paracrine communication..
a chemical signal acts within the tissue that produce it
endocrine communication
the signal reaches the target cells by way of circulation
Hormone Binding order
1. diffusion through membrane lipids.
2. binding of hormone to cytoplasmic or nuclear receptors
3. binding of hormone-receptor complex to DNA
4. Gene activation
5. transcription and mRNA production
6. translation and protein synthesis
7. alteration of cellular structure of activity and subsequent target cell response
What type of hormones bind to receptors located on the cell membrane
water-soluble hormones, such as insuline epinephrine
Which intracellular substance degrades cAMP, thus inactivating the response to a hormone?
phosphodiestrerase
growth factor hormones bind to
tyrosine kinase reptors
What adrenergic receptors increase cAMP levels
beta receptors
What hormone has intracellular receptors
cortisol
activation of genes, which increases protein synthesis in the cell...
is the mechanism of action of lipid-soluble hormone
after a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?
acts as a transcription factor and binds to Dna, activating a gene
Which hormone's receptor is always bound to DNA, even when the receptor is empty
thyroid hormone
Chaperone proteins
keeps intracellular receptors from binding to DNA before a hormone binds to the receptor
Catecholamines
derivatives of the amino tyrosine
An activated G protein can trigger
a fall in cAMP levels, the release of calcium ions from intracellular stores, the activation of adenyl cyclase, the opening of calcium ion channels in the membrane
Peptide hormones are
composed of amino acids
Steroids can cross the cell membrane because
they are lipid and the membrane is lipid
The hypthalamus acts as...
a neural and endocrine organ
membrane receptors are used by which hormones?
catecholamines, peptide hormones, and eicosanoids
steroid hormones
bind to receptors in the nucleus of their target cells
link between a first messenger and a second messenger in a cell that responds to peptide hormones is usually
a G protein
Insulin and epinephrine are
water soluble and bind to extracellular receptors
Increased activity of phosphodiesterase in a target cell would decrease its level of
cAMP
The brain region that exerts the most direct effects on the endocrine system is the
hypothalamus
diabetes insipidus occurs when the ______ lobe of the pituitary gland no longer releases ______.
posterior gland; ADH
Destruction of the supraoptic nucleus of the hypothalamus would have....
loss of ADH secretion
The primary function of ADH is to
decrease the amount of water lost at the kidneys
The hypothalamus controls secretion in the adenohypophysis by
secreting releasing and inhibiting factors into a tiny portal system
The hypophyseal portal system
has two capillary plexuses connected by short veins, carries neurosecretions to the anterior lobe of the pituitary, carries ADH and OXT, blood connection between the hypothalamus to the anterior pituitary.
Target cells for oxytocin
ductus deferens, prostate, uterus, mammary glands
The hormone produced by the paras intermedia of the adenohypophysis during early childhood is
MSH
Growth hormone....
speeds up metabolism, promotes bone growth, promotes muscle growth, spares glucose, and promotes amino acid uptake by cells
the pituitary hormone that triggers the release of thyroid hormone from the thyroid gland is
TSH
liver cells respond to growth hormone by releasing hormones called
somatomedins
The pituitary hormone that controls the release of glucocorticoids from the suprarenal cortex is
ACTH
The pituitary hormone that stimulates milk production by the mammary glands
Prolactin
Stimulates cell growth and replication by acclerating protein synthesis is
somatotropin
Lipid soluble hormones usually bind to
cytoplasmic receptors
ADH
causes the kidney to reduce water loss
Melanocyte-stimulating hormone is secreted by the human pars intermedia...
in very young children, during fetal development, in some disease processes, during pregnancy.
Used to accelerate labor and delivery is
both OXT and LH
Posterior pituitary lobe also called
neurohypophysis
Anterior pituitary lobe also called
adenohypophysis
Three parts of the anterior pituitary
the pars distalis, the pars indtermedia, and the pars tuberalis
Necessary for the production of thyroid hormone
iodine
Cells that are target cells for the hormone that causes a decrease in blood-calcium concentration?
osteoblasts
Effects of TH on peripheral tissue
increased.... heart rate, oxygen consumption, sensitivity to autonomic stimulation, body temp.
Mental and physical sluggishness and low body temperature may be signs of
hypothyroidism
C cells of the thyroid gland produce
calcitonin
increased levels of the hormone ______ will lead to the increased levels of calcium ion in the blood
PTH
TSH plays a key role in te
synthesis and release of thyroid hormones
inadequate iodine in diet may lead to
cretinism, hypothyroidism, high blood levels of TSH, myxedema
Thyroxine and calcitonin are secreted by the
thyroid gland
Thyroid hormones are structural derivatives of the amino acid
tyrosine
Patients with hyperthyroid diesease often exhibit
elevated.... heart rate, oxygen utilization, body temperature
excessive parathyroid hormone release causes
increased loss of bone minerals, elevated blood calcium, osteopenia
Hypersecreting tumor of the adrenal medulla causes
elevation of blood pressure and blood glucose concentration
The zona reticularis of the suprarenal cortex produces
androgens
The zona fasciculata of the suprarenal cortex produces
glucocorticoids
The zona glomerulosa
mineralocorticoids
The zona suprearenal medulla produces
catecholamines
a hormone that promotes gluconeogenesis in the liver is
cortisol
Helps to regulate the sodium ion content of the body is
aldosterone
Cushing disease results from an excess of
glucocorticoids
reduction of fluid losses at the kidneys due to retention of NA+ is the action of
aldosterone
Damage to cells of the zona fasciculata of the suprarenal cortex would result in
decreased ability to convert amino acids to glucose
A rise in cortisol would cause an increase in
rate of glycogen formation by the liver, rate of glucose synthesis by the liver, fatty acid metabolism by muscle cells, the level of fatty acids in the blood
A hormone that is synergistic to growth hormone is
cortisol
Emergency gland and helps body adjust to stress
adrenal
Increases and prolongs effects of the sympathetic nervous system
cortisol
Causes an anti-inflammatory action
glucocorticoids
Hormones from the adrenal cortex that regulate electrolyte balance are
mineralocorticoids
Aldosterone stimulates the reabsorption of______ and the excretion of _______
sodium ions; potassium ions
The suprarenal cortex produces steroid hormones called
corticosteriods
excessive secretion by the adrenal medulla can lead to
elevated.. heart rate, blood pressure, and blood glucose level
Melatonin ..
made from serotonin, produced by pinealocytes, exposure to light inhibits production, inhibits release of GnRH
Seasonal affective disorder (SAD) caused by
increased levels of melatonin
When blood glucose levels are high
the pancreas releases insulin
The liver cell responds to insulin by
taking in glucose and converting it to glycogen
When cells in the body respond to glucagon by breaking down glycogen and releasing glucose
liver cells
Body cells that respond to insulin include
liver cells, as well as most of other cells in the body
When blood glucose levels are low
the pancreas releases glucagon, which eventually causes blood glucose levels to increase
A fall in blood glucose concentration
activates secretion of a hormone from this gland
Pineal gland
promotes sleep, produces melatonin, receives inputs from the retina
Alpha cells are to______ as beta cells are to ______.
glucagon; insulin
The pancreatic hormone that causes blood sugar levels to fall is
insulin
Glucagon
raises blood sugar
Type II diabetes is characterized by
a lack of response by target cells to insulin
A rise in blood glucose level will trigger
storage of triglycerides, storage of glycogen, increase beta cell secretion
The enzyme renin is responsible for the activation of
angiotensin
Increases production of red blood cells
erythropoietin
The kidneys secrete
renin, erythropoietin, calcitriol, hormones to regulate sodium ion concentration
adipose cells produce a hormone called
leptin
Adipocytes produce a peptide hormone called
leptin
Heart secretes the hormone
atrial natriuretic peptide
Dominates during the alarm phase of the general adaptation syndrome (GAS) is
epinephrine
if stress lasts longer than a few hours, an individual will enter the
resistance phase of the GAS
Dominates during the resistance phase of GAS
Glucocorticoids
the exhaustion phase of the GAS is characterized by
failure to electrolyte balance
Hormones that produce different but complementary results are
integrative
Two hormones that have additive effects are
synergists
When one hormone is needed for a second hormone to produce an effect
permissive