Endocrine system

Ex. Somatostatin (inhibits insulin secretion)

Neurotransmitter and neuromodulators:
- secreted by nerve cells
- Ex. Nervous system function
Pheromones:
- secreted into env’t and modify behavior and
physiology of other individual in same species
Ex. Women and menstrual cycles
Hormones and neurohormones:
- secreted into blood and bind to receptor sites
Ex. Epinephrine and insulin

Function:

-Controls homeostasis
-Maintains water balance
-Controls uterine contractions
-Controls milk production
-Regulates ions (calcium, sodium, potassium)
-Regulates metabolism and growth
-Regulates heart rate and blood pressure
-Monitors blood glucose levels
-Aids the immune system
-Reproductive functions
Components of Endocrine System

Endocrine glands:
-secrete their product directly into blood stream
Chemical signal:
-molecules that are released from one location,
Components of Hormones
move to another location, and produce a response
Types of Chemical Signals Receptor site:
-location on a cell where hormone binds (lock)
Intracellular:
Target tissues:
-produce in one of part a cell and move to another
-group of cells that respond to specific hormones
part of same cell
Specificity:
Intercellular:
-specific hormones bind to specific receptor sites
-released from one cell and bind to receptors on
another cell
Types of Intercellular Signals

Autocrine:
-released by cells and a have local effect on same
cell type
Ex. Eicosanoids (released in response to
inflammation)
Paracrine:
-released by cells that affect other cell types in
close proximity

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How does this work? Ex. Blood glucose levels (insulin)
Other hormones:
-Hormones are secreted by endocrine glands
Ex. TSH signals thyroid gland to release thyroid
directly into bloodstream
hormone
-Hormones travel to all parts of body
Nervous system:
-Hormones (key) bind to receptor site (lock) on
Ex. Epinephrine and fight or flight response
target tissue
Negative Feedback:
-Response occurs
tells body when homeostasis is reached
How do hormones cause change?

-Alter cell activity of target tissues by increasing or

decreasing cell’s normal processes
-Change permeability of cell membrane by
opening or closing ion channels
-Synthesis of proteins
TYPES OF HORMONES

Water soluble -includes proteins,

peptides, amino acids
- most common
Ex. Growth hormone,
antidiuretic, prolactin,
etc.
Lipid hormones -includes steroids and
eicosanoids
Ex. LH, FSH, androgens

Hormone Receptors and Mechanisms of Action

-Lipid Soluble Hormones bind to Nuclear Receptors

-Water Soluble Hormones bind to Membrane-Bound
Receptors
-Intracellular Receptor Hormones

Regulation of Hormones

-Blood levels of chemicals:

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pituitary gland
FSH (Follicle-Stimulating) for females:
-Small gland in -Target tissue: follicles in ovaries
brain Function: follicle maturation and estrogen
-Controlled by
secretion
hypothalamus
FSH for males:
-Divided into 2
regions: anterior -Target tissue: seminiferous tubules (testes)
and posterior Function: sperm production
-Secretes at least Prolactin:
6 hormones -Target tissues: mammary glands and ovaries
Functions: milk production
Posterior Pituitary Gland
Antidiuretic Hormone (ADH):
-Target tissues: kidneys
-Functions: conserve water
Abnormalities:
Diabetes insipidus:
- low ADH
- kidneys to produce large amounts of dilute
(watery) urine
- can lead to dehydration and thirst
Oxytocin:
-Target tissues: uterus
Functions: increases uterine contractions during
labor

Anterior Pituitary Gland

Growth Hormone:
-Target tissues: most
-Functions: stimulates growth of bones,
muscles, and organs
Abnormalities:
-Too much GH causes giantism
-Too little GH causes pituitary dwarfism

Thyroid-Stimulating Hormone (TSH):

Target tissues: thyroid gland

-Functions: regulates thyroid gland secretions
Abnormalities:
-Too much TSH, thyroid gland enlarges
-Too little TSH, thyroid gland shrinks
GONADOTROPINS
LH (Luteinizing) for females:
-Target tissue: ovaries Thyroid Gland
Function: promotes ovulation and progesterone
-One of largest glands
production
-Requires iodine to function
LH for males:
Thyroid hormones:
-Target tissue: testes
-Target tissues: most
Function: sperm production and testosterone

University of Luzon-College of Nursing Escosiio-Esteves

Functions: regulates metabolic rates and is
needed for growth
Abnormalities of Thyroid Gland

aHypothyroidism: aHyperthyroidism:
-Decreased metabolism -Increased metabolism
-Weight gain, reduced -Weight loss, increased
appetite, fatigue appetite, nervousness
-Low temp. and pulse -Higher temp. and pulse
-Dry, cold skin -Warm, flushed skin
-Myxedema in adults -Graves’ disease (leads
-Cretinism in infants to goiter)

Adrenal Glands
-On kidneys
-2 regions medulla and cortex
Adrenal Medulla (inner portion):
-Epinephrine/Norepinephrine:
Target tissues: heart, blood vessels, liver, fat cells
-Functions: released as part of fight or flight
response.

Calcitonin:
-Target tissues: bones
Functions: secreted when blood Ca2+ levels
are high
Parathyroid gland
Parathyroid hormone (PTH):
-Target tissues: bones and kidneys
Functions: regulates blood Ca2+ levels
(more than calcitonin)
Adrenal Cortex (outer portion):
o If Ca 2+ is low then osteoclasts break down
Aldosterone:
bone matrix and less Ca 2+ is lost in urine. -Type of mineralocorticoids
o If Ca 2+ is high then osteoclasts don’t break Target tissues: kidneys
down bone matrix and more Ca 2+ is lost in Functions: causes Na+ and H2O to be retained and
urine. K+ to be secreted, indirectly involved with blood
pressure and blood volume.
Cortisol:

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-Type of glucocorticoids - between meals glucose levels drop and
Target tissues: most glucagon is secreted
-Functions: increases breakdown of fat and - glucagon allows glycogen to be broken
protein for energy uses reduces inflammatory and down into glucose
immune responses. Testes
Androgens: Testosterone:
-Target tissues: most - Target tissues: most
Functions: Functions: aids in sperm and reproductive
Males: secondary sexual characteristics organ development and function
Females: sex drive Ovaries
Pancreas Estrogen/Progesterone:
Organ in abdomen - Target tissues: most
Insulin: Functions: involved in uterine and mammary
-Target tissues: liver, skeletal muscle, adipose tissue gland development and menstrual cycle
Functions: Thymus gland
- regulates blood glucose levels Thymosin:
- after a meal glucose levels are high and insulin is Target tissues: immune system tissues
secreted. Functions: promotes immune system
- extra glucose is stored in form of glycogen development and function.
Pineal Body (Gland)
Melatonin:
Target tissues: hypothalamus
Functions: plays a role in onset of puberty and
controls circadian rhythms. Light
affects its function.

Abnormalities:
Diabetes mellitus:
- Causes: too little insulin or faulty
insulin receptors
- Symptoms: exaggerated appetite,
excess urine, dehydration, thirst, fatigue
- Type I: insulin dependent (daily
injections required)
- Type II: insulin independent, often found in obese
people, can be treated with diet but can turn into
type I
Glucagon:
- Target tissues: liver
Function:
- regulates blood glucose levels

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