endocrine system Flashcards
Endocrine system derived from the Greek words “____” meaning
within and “___” meaning to secrete.
endo, krino
endo means
within
krino means
secrete
Endocrine system is composed of _______ and _______ located throughout the body
endocrine glands, specialized endocrine cells
Endocrine glands secrete chemical messengers
called ___ into the bloodstream in order to
produce a specific response to _____ or ______
hormones, target tissues, effectors
The main regulatory functions of the endocrine system are the
- Metabolism
- Control of food intake and digestion
- Tissue Development
- Ion Regulation
- Water Balance
- Heart rate and blood pressure regulation
- Control of blood glucose and other nutrients
- Control of reproductive functions
- Uterine contractions and milk release
- Immune system regulation
Derived from the Greek word “hormon ” which
means to set in motion.
hormone
hormones are derived from the Greek word “____” which
means to set in motion.
hormon
Hormones: Chemical Nature
Has two chemical categories
- Lipid- soluble
- Water-soluble
Endocrine glands and
cells secrete very small amounts of chemical messengers called
hormones
nonpolar, and include steroid hormones, thyroid
hormones, and fatty acid derivative hormones, such as certain eicosanoids.
Lipid-soluble hormones
Small size and low solubility
in aqueous fluids.
Lipid-soluble hormones
Needs a binding protein for
transport
Lipid-soluble hormones
Diffuses across the cell
membrane
Lipid-soluble hormones
Lipid-soluble hormones, Receptor Location:
Nucleus
or cytoplasm
Ex: Steroid and thyroid
hormones
Lipid-soluble hormones
are polar molecules; they include protein hormones,
peptide hormones, and most amino acid derivative hormones
Water-Soluble Hormones
Vary from small to large and soluble in blood
Water-soluble hormones
• Large hormones dissolve directly into the blood and are delivered
to the target tissue without attaching to binding protein
Water-soluble hormones
Small hormones however need
attachment to larger protein to avoid being filtered out of the blood
Water-soluble hormones
Cannot diffuse through cell membrane
Water-soluble hormones
Receptor Location of water soluble hormones
plasma membrane’s outer surface
There are three types of stimuli which regulate
hormone release
- Humoral
- Neural
- Hormonal
Blood-borne chemicals which stimulate release of
some hormones are called
humoral stimuli.
Control of Hormone Section: When blood levels of certain substances changes,
glands release hormones to maintain normal
concentration of substances
Humoral Stimuli
Inhibition of Hormone Release
• A companion hormone exists to oppose those of the
secreted hormone and its actions.
humoral stimuli
Control of Hormone Section:
• Following an action potential, neurons release a
neurotransmitter into the synapse.
• Neurotransmitters will allow stimulation of the gland
to release hormone where it will travel to its target
neural stimuli
Neural stimuli
Control of Hormone Section:
• Following an action potential, neurons release a
______ into the _____
• Neurotransmitters will allow stimulation of the gland
to release hormone where it will travel to its target.
neurotransmitter, synapse
In neural stimuli, this allow stimulation of the gland
to release hormone where it will travel to its target
neurotransmitters
Neural stimuli
Inhibition of Hormone Release
• ____ inhibit targets just as often as they stimulate
targets.
• If the _____ is inhibitory, the target
endocrine gland does not secrete its hormone.
Neurons, neurotransmitter
It occurs when a secreted hormone stimulates the
secretion of other hormones. These hormones are
called tropic hormones.
hormonal stimuli
occurs when a secreted hormone stimulates the
secretion of other hormones. what do you call these hormones
tropic hormones
term usually reserved for
hormones from the hypothalamus.
releasing hormones
The hypothalamus secretes _____.
These releasing hormones stimulate the release of
hormone (tropic hormone) from the anterior
pituitary. The tropic hormone travels to the target
endocrine cell and stimulates the release of another
hormone
releasing hormones.
releasing hormones from the hypothalamus stimulate the release of ____ from anterior pituitary
tropic hormone
The _____ travels to the target
endocrine cell and stimulates the release of another
hormone.
tropic hormone
Hormonal stimuli, There are hormones that prevents the secretion of
other hormones. These hormones are called
“inhibiting hormones.”
hormone release caused by altered levels of certain critical ions or nutrients
humoral stimulus
hormone release caused by neural input
neural stimulus
hormone release caused by another hormone
hormonal stimulus
consists of ductless glands.
endocrine system
Some of the glands of the endocrine system are not limited to perform function to hormone secretion
The following are the endocrine glands and organs:
- Pituitary gland
- Thyroid gland
- Parathyroid gland
- Adrenal glands
- Pancreas
- Testes and Ovaries
- Thymus
- Pineal Gland
The pituitary gland is also called the
hypophysis
a small gland about the size of a pea
pituitary gland
It rest in a depression of the sphenoid bone inferior to
the hypothalamus of the brain.
pituitary gland
Two parts of pituitary gland
• Anterior pituitary
• Posterior pituitary
_____ is
made up of two lobes
connected by a narrow
band called ____
The thyroid gland, isthmus
One of the largest
endocrine glands.
thyroid gland
Appears more red than
surrounding tissues.
thyroid gland
Main function:
Secretion of thyroid
hormones
are synthesized and stored
within the thyroid follicles. These follicles
contain protein called “thyroglobulin” in
which hormones are attached
Thyroid hormones
Thyroid hormones are synthesized and stored
within the thyroid follicles. These follicles
contain protein called “____” in
which hormones are attached.
thyroglobulin
The synthesized hormones in thyroid follicles are
thyroxine/tetraiodothyronine(T4) and
triiodothyronine (T3)
The negative-feedback effect of thyroid hormones on the hypothalamus and
pituitary results in
increasing levels of thyroid hormones inhibiting the secretion of TSH-releasing hormone from the hypothalamus and inhibiting TSH secretion
from the anterior pituitary gland
Loss of negative feedback effect on hypothalamus and pituitary gland will result in
excess
TSH
causes enlargement of the thyroid. This
condition is called “goiter.
excess
TSH
enlargement of the thyroid. This
condition is called
goiter
When the normal rate of thyroid hormone
secretion is disrupted, growth and
development cannot proceed normally.
lack of thyroid hormones
Hypothyroidism
In infants, hypothyroidism can result in
cretinism
characterized by developmental delay, short stature,
and abnormally formed skeletal structures
Cretinism
In adults, it can result to decreased metabolic rate,
sluggishness, reduced ability to perform routine tasks and myxedema.
elevated rate of thyroid
hormones
Hyperthyroidism
type of of hyperthyroidism that
results when the immune system produces abnormal
proteins that are similar in structure and function to
TSH.
grave’s disease
an autoimmune disease that
causes hyperthyroidism. This disease occurs when the immune system produces
abnormal proteins that are similar in structure and function to TSH, which
overstimulates the thyroid gland.
graves disease
accompanied by bulging
of the eyes
Graves disease
Four glands embedded in the posterior wall of the
thyroid gland
Parathyroid Gland
These glands secrete the parathyroid hormone
(PTH) which is essential in regulation of calcium
level.
Parathyroid Gland
elevated rate of PTH
Hyperparathyroidism
Causes softening, deformity and/or fracture of the
bone.
Hyperparathyroidism
low rate of PTH
Hypoparathyroidism
Results from injury to or the surgical removal of
thyroid and parathyroid glands.
Hypoparathyroidism
Two small glands
located superior to
each kidney
adrenal glands
Each adrenal gland
has an inner part
called the _____ and the
outer part called
the ______
adrenal
medulla, adrenal cortex
The principal hormone released by the adrenal
medulla is _____. Small amounts of
______ are also released
epinephrine, norepinephrine
Related to fight or flight reaction, stress and low
blood sugar.
Adrenal Medulla
Epinephrine and norepinephrine are called the
fight-or-flight hormones
secretes three classes of
steroid hormones: 1)mineralocorticoids
2)glucocorticoids 3)androgens
Adrenal Cortex
The adrenal cortex secretes three classes of
steroid hormones:
1)mineralocorticoids
2)glucocorticoids 3)androgens
the hormones and the receptors of each class have
unique structural and functional characteristics
Adrenal Cortex
regulates blood volume
and levels of potassium and sodium ions.
Mineralocorticoids
Major hormone of Mineralocorticoids
aldosterone
Binds to receptor molecules in the kidney, but it also
affects the intestine, sweat glands and salivary
glands
Aldosterone
causes sodium ions and water to be
retained in the body
Aldosterone
regulates blood nutrient
levels
Glucocorticoids
help to provide energy for cells by stimulating the increased use
of lipids and proteins
Glucocorticoids
Major hormone of glucocorticoids
cortisol
• Responds in stressful situations
• Increases the breakdown of proteins and lipids. It
also increases their conversion to forms of energy
the body can use.
• Reduces inflammatory and immune responses.
(Cortisone)
cortisol
third class of hormones, secreted by the inner layer of the adrenal cortex, is
composed of the
adrenal androgens
Gonadocorticoids -
Androgens
Stimulate the development of male sexual
characteristics
androgen
both male and female possess these
hormones.
androgen
In adult males, most androgens are
secreted by the
testes
In adult females, the adrenal androgens influence the
female
sex drive
Abnormally high level of ___ hormone
can exaggerate male characteristics in both
male and female
androgen
Consists of the pancreatic islets (Islets of
Langerhans)
pancreas
pancreatic islets (Islets of
Langerhans) secrete three hormones:
1)insulin
2)glucagon and 3)somatostatin
pancreas: These hormones (3) help regulate levels of
nutrients especially glucose.
1)insulin
2)glucagon and 3)somatostatin
pancreas:
_____has an essential role in
maintaining homeostasis
Blood glucose
Pancreas:
A decreased blood glucose will cause tissues to
break down lipids and proteins to provide an
alternative source of energy.
Decreased blood glucose -> breaking down of lipids and proteins-> alternative source of energy ->
As lipids break down, the liver converts fatty acids
to ____. As a result, ____ can occur.
ketones, acidosis
When blood glucose levels are very low, the breakdown of
lipids can cause the release of enough fatty acids and ketones to reduce the pH of
the body fluids below normal, a condition called
acidosis
Elevated blood glucose levels stimulate beta cells to secrete
insulin
The kidneys produce large volume of urine
containing substantial amount of glucose. However,
dehydration can result because of rapid loss of
water in the form of urine
Increased blood glucose level
Released from the beta cells
insulin
The major target tissues for insulin are the
liver, adipose tissue,
muscle and satiety area of hypothalamus.
Increases when there is elevated blood glucose level
insulin
Increases in response to parasymphatetic
stimulation associated with digestion
insulin
Increases when there is an increased blood levels of
certain amino acids
insulin
the body
’s inability to regulate blood glucose levels within the
normal range
Diabetes mellitus
There are two types of diabetes mellitus
type 1 and 2
Occurs when too little insulin is secreted from
the pancreas.
Type 1 Diabetes Mellitus
Occurs when lack of number of insulin
receptors on target cells or defective target cells
do not respond normally to insulin.
Type 2 Diabetes Mellitus
released from the alpha cells when blood glucose
levels are low
glucagon
binds to membrane-bound receptors primarily in the liver, causing the glycogen stored in the liver to be converted to glucose.
glucagon
____ is then released into the blood to increase blood glucose levels.
glucose
normal blood glucose level
90 mg / 100 ml
released by the delta cells in
response to food intake. inhibits the secretion of insulin and
glucagon and inhibits gastric tract activity.
Somatostatin
The testes (male) and
ovaries (female)are
structures of the
reproductive tract which
has an essential role in
reproduction
The male sex hormone is ____ which is
secreted by the testes
testosterone
is responsible for the
growth and development of the male
reproductive structures and as well as sexual
characteristics.
testosterone
The female sex hormones are
estrogen and progesterone
hormones that work together
on the growth and development of the female
reproductive structures, breasts, hips, thighs
and as well as sexual characteristics.
estrogen and
progesterone
lies in the upper part of the
thoracic cavity which functions in immunity
thymus
thymus secretes the hormone “_____” which aids
in the development of the T-cells.
thymosin
a small, pinecone-shaped
structure located superior and posterior to the
thalamus of the brain.
pineal gland
pineal gland produces a hormone called___
melatonin
This produces the hormone “melatonin” which
decreases secretion of LH and FSH
pineal gland
