�Introduction

�Hormones

�Functions

�Table’s 16-7

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Endocrine system (21)

The endocrine and nervous are

both communicators of the body.

The endocrine is a slow

communicator while the nervous

system is a fast communicator.

The nervous system collects and

processes information, analyzes

it, and generates coordinated

output to control complex

behaviors. The nervous system

also is partly responsible for

homeostasis. It works in

conjunction with the endocrine

system by employing nerve

impulses and by responding

rapidly to stimuli to adjust body

processes. (2)

Overall function regulation of effectors to maintain homeostasis

Control by regulatoryfeedbacks loops Yes(endocrine reflexes)

Effector tissues endocrine effectors virtually all tissues

Effector cells target cells (3)

Facial

Skeleton

(21)

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*Organic chemical substances secreted by ductless glands (or endocrine glands) and are released into the blood stream for onward transportation to their target organs.

*Regulate a variety of body functions.

-The way the body uses food growth

-Sex and reproduction the regulation of the composition of the blood

-The body’s reaction to emergencies and the control of hormones themselves(4)

(5)

*

*Molecules manufactured by the endocrine cells from cholesterol

*Derived from a common molecule, being characterized by a chemical group at the core

of each molecule

*Ex: Cortisol. Aldosterone, estrogen, progesterone, and (6)

*

*Do not enter the cell but bind to plasma membrane receptors, generating a chemical

signal (second messenger) inside the target

cell.

*Five different second messenger chemicals, including cyclic AMP have been identified.

Second messengers activate other intracellular

chemicals to produce the target cell

response.(7)

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*

is any member of a group of lipid

compounds that are derived

enzymatically from fatty acids and

have important functions in the

animal body. Every prostaglandin

contains 20 carbon atoms,

including a 5-carbon ring.(7)

**is an endocrine gland about the size of a pea and weighing 0.5 gramsin humans. It is not a part of the brain. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold. The pituitary is functionally connected to the hypothalamus by the median eminence via a small tube called the infundibular stem. The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid bone in the middle cranial fossa at the base of the brain. The pituitary gland secretes nine hormones that regulate homeostasis(8) (9)

*

*is a small endocrine gland in the vertebrate brain. It produces the serotonin derivative

melatonin, a hormone that affects the

modulation of wake/sleep patterns and

seasonal functions. (10)

(11)

*

*The thyroid gland is found in the neck, below the thyroid cartilage (which forms the laryngeal prominence, or "Adam's apple"). The isthmus (the bridge between the two lobes of the thyroid) is located inferior to the cricoid cartilage.

*

*The thyroid gland controls how quickly the body uses energy, makes proteins, and controls how sensitive the body is to other hormones. It participates in these processes by producing thyroid hormones, the principal ones being triiodothyronine(T3) and thyroxine which can sometimes be referred to as tetraiodothyronine (T4). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. T3 and T4 are synthesized from both iodine and tyrosine. The thyroid also produces calcitonin, which plays a role in calcium homeostasis.(12)

*

*The parathyroid glands are small endocrine glands in the neck that produce parathyroid

hormone. Humans usually have four

parathyroid glands, which are usually located

on the rear surface of the thyroid gland, or, in

rare cases, within the thyroid gland itself or in

the chest. Parathyroid glands control the

amount of calcium in the blood and within the

bones.(13)

(14)

*

*the adrenal glands are endocrine glands that sit at the top of the kidneys; in humans, the right adrenal

gland is triangular shaped, while the left adrenal

gland is semilunar shaped. They are chiefly

responsible for releasing hormones in response to

stress through the synthesis of corticosteroids such

as cortisol and catecholamines such as epinephrine

and norepinephrine. They also produce androgens.

The adrenal glands affect kidney function through

the secretion of aldosterone, a hormone involved in

regulating the osmolarity of blood plasma. (15)

Functions

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*

*Triangular-shaped glands located on top of the kidneys. They produce hormones such as

estrogen, progesterone, steroids, cortisol, and

cortisone, and chemicals such as adrenalin

(epinephrine), norepinephrine, and dopamine. (16)

*

* Throughout the pancreas are clusters of cells called the islets of Langerhans. Islets are made

up of several types of cells, including beta cells

that make insulin.

*

*The testes are two egg-shaped male reproductive organs located in the scrotum.

They produce sperm and the male hormone,

testosterone.

*

*The placenta is a structure that develops in your uterus during pregnancy. The placenta

provides oxygen and nutrients to your growing

baby and removes waste products from your

baby's blood. It attaches to the wall of your

uterus, and your baby's umbilical cord arises

from it. In most pregnancies, the placenta

attaches at the top or side of the uterus.

*

*The thymus is a small organ in your upper chest, under your breastbone. Before birth and

during childhood, the thymus helps the body

make a type of white blood cell. These cells

help protect you from infections.

*

*The gastrointestinal mucosa forms a barrier between the body and a lumenal environment which not only contains nutrients, but is laden with potentially hostile microorganisms and toxins. The challenge is to allow efficient transport of nutrients across the epithelium while rigorously excluding passage of harmful molecules and organisms into the animal. The exclusionary properties of the gastric and intestinal mucosa are referred to as the gastrointestinal barrier.

*

*The heart is a muscular organ about the size of a fist, located just behind and slightly left of

the breastbone. The heart pumps blood

through the network of arteries and veins

called the cardiovascular system. The heart

moves the hormones throughout the body.

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Hormone Source Targets Principal Action

Growth hormone-releasing hormone

GRH

Hypothalamus Adenohypophysis

(somatotrophs)

Stimulates secretion of growth hormone

Growth hormone- inhibiting hormone

GIH, or somatostatin

Hypothalamus Adenohypophysis

(somatotrophs)

Inhibits secretion of growth hormone

Corticoptropin- releasing hormone CRH Hypothalamus Adenohypophysis

(corticotrophs)

Stimulates release of adrenocorticotrophic hormone ACTH

Thyrotropin-releasing hormone TRH Hypothalamus Adenohypophysis

(thyrotrophs)

Stimulates release of thyroid-stimulating TSH

Gonadotropin- releasing hormone

GNRH

Hypothalamus Adenohypophysis

(gonadotrophs)

Stimulates release of gonadotropins (FSH and LH)

Prolactin-releasing hormone PRH Hypothalamus Adenohypophysis

(corticotrophs)

Stimulates secretion of prolactin

Prolactin- inhibiting hormone PIH Hypothalamus Adenohypophysis

(corticotrophs)

Inhibits secretion of prolactin

Growth hormone GH (somatotrophs

[STH])

Adenohypophysis

(somatotrophs)

General Promotes growth by stimulating protein anabolism

Prolactin PRL (lactogenic hormone) Adenohypophysis

(lactotrophs)

Mammary glands

(alveolar secretory

cells)

Promotes milk secretion

Thyroid-stimulating hormone TSH Adenohypophysis

(thyrotrophs)

Thyroid gland Stimulates development and secretion in the thyroid gland

Adenocorticotrophic hormone ACTH Adenohypophysis

(corticotrophs)

Adrenal cortex Promotes development and secretion in the adrenal cortex

Follicle-stimulating hormone FSH Adenohypophysis

(gonadotrophs)

Gonads (primary

sex organs)

Female: promotes development of ovarian follicle; stimulates

estrogen secretion

Male: promotes development of testis; stimulates sperm production

Luteinizing hormone LH Adenohypophysis

(gonadotrophs)

Gonads Female: triggers ovulation; promotes development of corpus luteum

Male: simulates production of testosterone

Antidiuretic hormone ADH Neurohypophysis Kidney Promotes water retention by kidney tubules

Oxytocin OT Neurohypophysis Uterus and

mammary gland

Stimulates uterine contractions; stimulates ejection of milk into

mammary glands

Hormone Source Targets Principal Action

Triiodothyronine (T3) Thyroid gland (follicular cells) General Increase rate of metabolism

Tetaiodothyronine (T4)

or thyroxine

Thyroid gland (follicular cells) General Increases rate of metabolism (usually converted to T3 first)

Calcitonin CT Thyroid gland (parafollicular cells) Bone tissue Increases calcium storage in bone; lowering blood Ca++ levels

Parathyroid hormone

PTH or parathromone

Parathyroid glands Bone tissue and kidney Increases removal from storage in bone and produces the

active form of vitamin D in the kidneys, increasing absorption

of calcium by intestines and increasing blood Ca++ levels

Aldosterone Adrenal cortex (zona glomerlulosa) Kidney Stimulates kidney tubules to conserve sodium, which, in turn,

triggers, the release of ADH and the resulting conservation of

water by the kidney

Cortisol (hydrocortisone) Adrenal cortex (zona fasciculata) General Influences metabolism of food molecules; in large amounts, it

has an anti-inflammatory effect

Adrenal androgens Adrenal cortex (zona reticularis) Sex organs, other

effectors

Exact role uncertain, but may support sexual function

Adrenal estrogens Adrenal cortex (zona reticularis) Sex organs Thought to be physiologically insignificant

Epinephrine

(adrenaline)

Adrenal medulla Sympathetic effectors Enhances and prolongs the effects of the sympathetic division

of the autonomic nervous system

Norepinephrine Adrenal medulla Sympathetic effectors Enhances and prolongs the effects of the sympathetic division

of the autonomic nervous system

Glucagon Pancreatic islets (alpha [a] cells or

A cells)

General Promotes movement of glucose from storage and into the

blood

Insulin Pancreatic islets (beta [b] cells or B

cells)

General Promotes movement of glucose out of the blood and into

cells

Somatostatin Pancreatic islets (delta [d] cells or D

cells)

Pancreatic cells and

other effectors

Can have general effects in the body, but primary role seems

to be regulation of secretion of other pancreatic hormones

Pancreatic polypeptide Pancreatic islets (pancreatic

polypeptide [PP] of F cells)

Intestinal cells and

other effectors

Exact function uncertain, but seems to influence absorption

in the digestive tract

*Group didn’t do all their citations….

*-megan