Endocrine System Flashcards
Second messenger system of the body
Uses chemical messages (hormones)
that are released into the blood
Endocrine System
Several major
processes that Hormones control (5)
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism
Cells secrete hormones into
___
extracellular fluids
Amino acid-based hormones (3)
Proteins
Peptides
Amines
Hormones that are:
– made from cholesterol
– made from highly
active lipids
Steroids;
Prostaglandins
Hormones can alter cellular activity
by increasing or decreasing the rate of a
____rather than
by stimulating performance of a new one
normal metabolic process
Hormone levels in the blood are maintained by __
negative feedback
mechanisms of hormone action can be achieved through (2)
Direct gene activation;
Second-messenger systems
stimuli of endocrine glands
Hormonal;
Humoral;
Neural
Changing blood
levels of certain
ions stimulate
hormone release
Humoral Stimuli
Neural Stimuli of Endocrine Glands:
___ stimulate
hormone release,
and the __are said to
respond to neural
stimuli.
nerve fibers;
endocrine
cells
Size of a grape
Hangs by a stalk from the hypothalamus
Pituitary Gland
The pituitary gland is Protected by the ___
sphenoid bone
Pituitary gland functional lobes:
Anterior pituitary – glandular tissue
Posterior pituitary – nervous tissue
Six anterior pituitary hormones:
Two affect ____
Four stimulate other ___
non-endocrine targets;
endocrine glands
(tropic hormones)
Characteristics of all anterior pituitary
hormones (3)
Proteins (or peptides)
Act through second-messenger systems
Regulated by hormonal stimuli, mostly
negative feedback
Hormones of the Anterior Pituitary (5)
Growth Hormone (GH);
Prolactin (PRL);
Adrenocorticotropic hormone (ACTH);
Thyroid-stimulating hormone (TSH);
Gonadotropic hormones;
Stimulates and maintains milk production
following childbirth; Function in males is unknown
Prolactin (PRL)
General metabolic hormone of:
Anterior pituitary =
Thyroid gland =
Anterior pituitary = growth hormone
Thyroid gland = thyroid hormone
Major effects are directed to growth of skeletal muscles and long bones;
Growth Hormone (GH)
Causes amino acids to be built into proteins; Causes fats to be broken down for a source of energy
Growth Hormone (GH)
Regulates endocrine activity of the adrenal cortex
Adrenocorticotropic hormone (ACTH)
Influences growth and activity of the thyroid
Thyroid-stimulating hormone (TSH)
Regulate hormonal activity of the gonads
Gonadotropic hormones
Gonadotropic hormones
Follicle-stimulating hormone (FSH);
Luteinizing hormone (LH)
Stimulates follicle development in
ovaries; Stimulates sperm development in
testes
Follicle-stimulating hormone (FSH)
Triggers ovulation; Causes ruptured follicle to become the corpus luteum
Luteinizing hormone (LH)
Stimulates testosterone production in males
interstitial cell-stimulating
hormone (ICSH)
Hormones of the Posterior Pituitary (2)
Oxytocin;
Antidiuretic hormone (ADH)
Stimulates contractions of the uterus during
labor; Causes milk ejection
Oxytocin
Can inhibit urine production; in large amounts, causes vasoconstriction
leading to increased blood pressure (vasopressin)
Antidiuretic hormone (ADH)
Found at the base of the throat; Consists of two lobes and a connecting
isthmus
Thyroid Gland
Thyroid Gland Produces two hormones
Thyroid hormone
Calcitonin
Composed of two active iodine containing hormones
Thyroid hormone
two active iodine
containing hormones of thyroid:
___ – secreted by thyroid
follicles
____– conversion of T4 at
target tissue
Thyroxine (T4);
Triiodothyronine (T3)
Decreases blood
calcium levels by
causing its deposition on bone;
calcitonin
calcitonin is…
Produced by ___
cells; Antagonistic to
___
hormone
C (parafollicular);
parathyroid
Tiny masses on the posterior of the
thyroid; Secrete parathyroid hormone
Parathyroid Glands
parathyroid hormone:
Stimulate ___to remove calcium
from bone
Stimulate the __ and __ to
absorb more calcium
osteoclasts;
kidneys and intestine
Raise calcium levels in the blood
parathyroid hormone
Sits on top of the kidneys
Adrenal Glands
two glands of adrenal glands:
___– outer glandular region in three layers
___– inner neural tissue region
Cortex;
Medulla
Hormones of the Adrenal Cortex (3)
Mineralocorticoids (mainly aldosterone);
Glucocorticoids (including cortisone and cortisol);
Sex hormones
Produced in outer adrenal cortex; Regulate mineral content in blood, water,
and electrolyte balance
Mineralocorticoids (mainly aldosterone)
this adrenal cortex hormone’s Target organ is the kidney
Mineralocorticoids (mainly aldosterone
Mineralocorticoids (mainly aldosterone Production is…
stimulated by __ and __;
inhibited by ___
renin and aldosterone;
atrial natriuretic peptide
Produced in the middle layer of the adrenal
cortex;
Promote normal cell metabolism
Glucocorticoids (including cortisone and
cortisol)
Help resist long-term stressors; Released in response to increased blood levels of ACTH
Glucocorticoids (including cortisone and cortisol)
Produced in the inner layer of the adrenal
cortex
Sex hormones
sex hormones
Androgens (male) and some estrogen
(female)
Hormones of the Adrenal Medulla
catecholamines= Epinephrine
Norepinephrine
These hormones prepare the body to
deal with short-term stress
catecholamines= Epinephrine
Norepinephrine
The ___is a mixed gland
pancreas
hormones of pancreatic islets
insulin
glucagon
– allows glucose to cross plasma
membranes into cells from beta cells
Insulin
– allows glucose to enter the
blood from alpha cells
Glucagon
These hormones are antagonists that
maintain blood sugar homeostasis
Insulin;
Glucagon
Found on the third ventricle of the brain; Secretes melatonin
Pineal Gland
Helps establish the body’s wake and sleep cycles
melatonin
Located posterior to the sternum; Largest in infants and children
Thymus
Thymus Produces __
thymosin
Matures some types of white blood cells; Important in developing the immune system
thymosin
Hormones of the Ovaries (2)
Estrogens;
Progesterone
Estrogens produced by:
Progesterone produced by:
estrogen= Graafian follicles or the placenta
progesterone=corpus luteum
Stimulates the development of secondary female characteristics; Matures female reproductive organs
Estrogens
Helps prepare the uterus to receive a fertilized
egg; maintain pregnancy; Prepares the breasts to produce milk
Estrogens
Acts with estrogen to bring about the menstrual cycle; Helps in the implantation of an embryo in
the uterus
Progesterone
Hormones of the Testes
androgens (testosterone)
___ of testes are hormone
producing; __is the most important androgen
Interstitial cells; Testosterone
Responsible for adult male secondary sex characteristics; Promotes growth and maturation of male reproductive system; Required for sperm cell production
Testosterone
Other Hormone-Producing tissues and Organs
Parts of the small intestine
Parts of the stomach
Kidneys
Heart
Many other areas have scattered endocrine cells
Endocrine Function of the Placenta (3)
Produces hormones that maintain the
pregnancy;
hormones play a part in the delivery of the baby
Produces HCG
___is brought about by lack of efficiency of the ovaries
Menopause
