The document discusses the endocrine system and hormones, explaining how hormones are released from glands and target specific cells through receptor proteins to regulate bodily functions like growth, metabolism, and reproduction. It provides information on different types of hormones based on their chemical structure and source, and includes tables listing major hormones and their functions.

1. Edition 4
Hormones, The Perfect
Storm!
Inside:
Introduction
Hormones
Functions of
hormones
Tables

2. Introduction:
1. How do the nervous and endocrine systems work
together?
To put it simply, your nervous and endocrine systems continuously monitor the
well-being of each of the billions of cells in your body, and they continuously take action
through messenger systems to keep all of your cells as healthy as possible. (14) ©
The nervous and endocrine systems are related in three main areas, structure,
chemical, and function. The endocrine and nervous system work parallel with each
other and in conjunction function in maintaining homeostasis, development and
reproduction. Both systems are the communication links of the body and aid the body’s
life systems to function correctly and in relation to each other. (13) ©
2. What is the method in which the endocrine system
undergoes its functions?
Hormones regulate bodily functions and are specific in what responses they
elicit. As hormones are released into the bloodstream they can only initiate responses in
target cells, which are specifically equipped to respond. Each hormone due to its
chemical structure is recognized by those target cells with receptors compatible with
their structure. Once a hormone is released, the first step is the specific binding of the
chemical signal to a hormone receptor, a protein within the target cell or built into the
plasma membrane. The receptor molecule is essential to a hormones function. The
receptor molecule translates the hormone and enables the target cell to respond to the
hormones chemical signal. The meeting of the hormone with the receptor cell initiates
responses from the target cell. These responses vary according to target cell and lipid
solubility. (13) ©
(18) ©

3. HORMONES!
Functions:
Tropic hormones (stimulate growth), sex hormones (target reproductive tissues), and anabolic
hormones (stimulate anabolism in their target cells) are all hormones classified by their general
functions.
Structures:
Hormones get classified by their chemical structure
Steroid Hormones:
Manufactured by endocrine cells from cholesterol, an important type of lipid in the human body.
Because steroids are lipid soluble, they can easily pass through the phospholipid plasma membrane of
target cells.
Non-steroid Hormones:
Synthesized primarily from amino acids rather than from cholesterol. Some are protein hormones; they
are long folded chains of amino acids, and a structure type of protein molecules of any sort.
How do Hormones work?
1. Lock and Key: The amino acid structure of the hormone is the key and the receptor is a lock. In
order for the key hormone to fit in the lock receptor, the hormone –receptor complex must be
an exact match.
2. What happens when hormones combine? : A specific hormone combines with a specific
receptor site, and forms a combination and a reaction of both.

4. Prostaglandins are a unique group of lipid molecules that serve important and widespread integrative
functions in the body but do not meet the usual definition of a hormone. They are rapidly metabolized,
so that circulating levels are extremely low. There are at least 16 different types of prostaglandins that
fall into nine structural classes. They have been isolated and identified from a variety of tissues, the first
being found in semen, attributed to the prostate gland. Other tissues that secrete prostaglandins are
kidneys, lungs, iris, and brain. ©8
The pituitary gland is small but mighty located within the skill on the ventral surface of the brain. It has
a stem like stalk and connects to the hypothalamus. It may look like one gland but it is actually 2, the
anterior and posterior pituitary glands. The anterior is divided into 2 parts, the pars anterior and the
pars intermedia. Their secretions are classified by these 5 types, somatotrophs, which secrets growth
hormone, corticotrophs, responsible for secreting adrenocorticotropic hormone, thyrotrophs, that
secrete thyroid stimulating hormone, lactotrophs, who secret prolactin, and gonadotrophs, they secrets
luteinizing hormone and follicle stimulating hormone. The posterior pituitary serves as storage and
release site for two hormones, antidiuretic hormone and oxytocin. ©8
The pineal gland is a pine cone shaped structure located on the dorsal aspect of the brain’s
diencephalon region. It works as a member of the nervous system and the endocrine system. It
functions to support the body’s biological clock that regulated out patterns of eating, sleeping,
reproduction, and behavior. Melatonin, the principal pineal secretion is thought to induce sleep. It also
plays into a person’s mood. ©8
The thyroid gland is made up of 2 large central lobes and a narrow connecting isthmus. It’s located in
the neck. It’s composed of tiny structural units called follicles, the site of thyroid hormone synthesis.
Each follicle is a small hollow sphere with a wall of simple cuboidal glandular epithelium that’s filled with
thick fluid called the thyroid colloid which contains thyroglobulin. The thyroid hormone is actually 2
different hormones, tetraiodothyronine or triiodothyronine. There is another gland produced called
calcitonin, which technically isn’t called a thyroid hormone because it was discovered after the others.
©8
Parathyroid gland- Function: Controls and distributes the calcium in our blood and bones.
Location: Located next to, and sometimes inside the thyroid gland.
Hormones:Parathormone or Parathyrin.
Adrenal Gland- Function: Releases hormones in response to stress.
Location: above kidney, and next to pancreas.
Hormones: Cortisol, Aldosterone and Androgens.
Pancreatic Islets- Function: secretes Insulin and Glucagon
Location: Pancreas

5. Hormones: Insulin and Glucagon
Gonads- Function: Produces gametes
Location: Testes in males, Ovaries in Females
Hormones: Gametes
Placenta- connects fetus to utirne wall, produces pregnancy related hormones, including chorionic
gonadotropin, estrogen, and progesterone.
Thymus- located in upper chest, underneath breast bone, helps the body make white blood cells that
help fight against infections
Gastric and intestinal mucosa- allow efficient transport of nutrients across the epithelium while
excluding passage of harmful molecules and organisms, located in a layer of the stomach
Heart- pumps oxygen-rich blood to every living cell in the body, non-beating heart results in death, the
heart beats approximately 80,000 to 100,000 pumps per day. it is located in the chest. Blood is pumped
through arteries, it is all a continuous cycle. Hormones Chart
Hormone Source Target Principal Action
Growth hormone Hypothalamus Adenohypophysis Stimulates secretion of
releasing hormone (somatotrophs) growth hormone
(GRH)
Growth hormone- Hypothalamus Adenohypophysis Inhibits secretion of
inhibiting hormone (somatotrophs) growth hormone
(GIH) or somatostatin
Corticotropin-releasing Hypothalamus Adenohypophysis Stimulates release of
hormone (CRH) (corticotrophs) ACTH
Thyrotropin-releasing Hypothalamus Adenohypophysis Stimulates release of
hormone (TRH) (thyrotrophs) TSH
Gonadotropin-releasing Hypothalamus Adenohypophysis Stimulates release of
hormone (GNRH) (gonadotrophs) (FSH) and (LH)
Prolactin-releasing Hypothalamus Adenohypophysis Stimulates secretion of
hormone (PRH) (coritcotrophs) prolactin
Prolactin-inhibiting Hypothalamus Adenohypophysis Inhibits secretion of
hormone (PIH) (corticotrophs) prolactin
Growth hormone Adenohypophysis General Promotes growth by
somatotropin (STH) (somatotrophs) stimulating protein
anabolism and fat
mobilization
Prolactin (PRL) Adenohypophysis Mammary Glands Promotes milk secretion
(lactotrophs)
Thyroid-stimulating Adenohypophysis Thyroid Gland Stimulates
hormone (TSH) (thyrotrophs) development and
secretion in the thyroid
gland
ACTH Adenohypophysis Adrenal Cortex Promotes development
(corticotrophs) and secretion in the

6. adrenal cortex
Follicle-stimulating Adenohypophysis Gonads Female: promotes
hormone (gonadotrophs) development of ovarian
follicle, simulates
estrogen secretion
Male: promotes
development of testis;
stimulates sperm
production
Luteinizing hormone Adenohypophysis Gonads Female: triggers
(LH) (gonadotrophs) ovulation; promotes
development of corpus
leteum
Male: stimulates
production of
testosterone
Antidiuretic hormone Nuerohypophysis Kidney Promotes water
(ADH) retention by kidney
tubules
Oxytocin (OT) Nuerohypophysis Uterus and mammary Stimulates uterine
glands contractions; stimulates
ejection of milk into
mammary ducts
Triiodothyronine Thyroid gland (follicular General Increases rate of
cells) metabolism
Tetraiodothyronine or Thyroid gland (follicular General Increases rate of
thyroxine cells) metabolism usually
converted to T3 first
Calcitonin Thyroid gland Bone tissue Increases calcium
(parafollicular cells) storage in bone,
lowering blood Ca ++
levels
Parathyroid hormone Parathyroid glands Bone tissue and kidney Increases calcium
(PTH) removal from storage in
bone and produces the
active form of vitamin D
in the kidneys
Aldosterone Adrenal cortex Kidney Stimulates kidney
(zonaglomerulosa) tubules to conserve
sodium- release of ADH
Cortisol Adrenal cortex (zona General Influences metabolism
fasciculate) of food molecules
Adrenal Androgens Adrenal cortex Sex organs May support sexual
(zonareticularis) function
Adrenal estrogens Adrenal cortex Sex Organs Insignificant
(zonareticularis)

7. Epinephrine Adrenal medulla Sympathetic effectors Enhances and prolongs
the effects of the
sympathetic division of
the ANS
Norepinephrine Adrenal medulla Sympathetic effectors Enhances and prolongs
the effects of the
sympathetic division of
the ANS
Glucagon Pancreatic Islets (A General Promotes movement of
cells) glucose from storage
into the blood
Insulin Pancreatic Islets (B General Promotes movement of
cells) glucose out of the blood
and into the cells
Somatostatin Pancreatic Islets (D cells) Pancreatic cells and other Regulation of secretion of
effectors other pancreatic
hormones
Pancreatic Polypeptide Pancreatic Islets (F cells) Intestinal cells and other Seems to influence absorption in
the digestive tract.
effectors
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