 Endocrine cells release hormones into the bloodstream
 Hormones go throughout the body and affect many tissues and organs at the same time
 Effects are slow to appear and last a long time even if there is no additional hormone released
 Hormones control many long term processesi.e. development of embryo, growth, sexual maturation, reproduction

 Endocrine
 Produce hormones
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Hormones released directly into bloodstream
No ducts
 Exocrine
 Produce a variety of secretions
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Release secretion to a surface (internal and external)
Have ducts

Both are control systems for the body.
How are they different?
 Endocrine
 Slow acting
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Long duration
Targets all tissues and cells
 Nervous
 Quick acting
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Short duration
Targets specific cells

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Control many long term processes
Many chemicals act as both hormones and neurotransmitters
 Adrenal medulla and hypothalamus have both endocrine and nervous functions
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Most are either peptide hormones (protein based) or steroids (lipid based)
Hormones work by changing types, action, amount or properties of enzymes

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Simplest endocrine reflexes
 Disturbance in homeostasis endocrine response homeostasis restored
 More complex require more steps:
 Disturbance in homeostasis activates the pituitary gland messenger to another gland response restore homeostasis
(examples: blood sugar and pancreas)

Pituitary = “master gland”
 The most complex endocrine reflexes involve the hypothalamus
 Disturbance in homeostasis activates the
Hypothalamus pituitary targets a specific gland stimulates a response homeostasis is restored

 Main connection of nervous and endocrine systems
 3 functions:
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Controls sympathetic output of adrenal medulla
Acts as endocrine gland —releases hormones into the posterior pituitary gland
 Secretes hormones that control activity of the anterior pituitary
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Releasing hormones
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Inhibiting hormones

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Also known as Hypophysis
2 parts —anterior and posterior
 9 hormones come from pituitary gland
(all peptide)

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Neurohypophysis
2 Hormones:
1. ADH (antidiuretic hormone
/vasopressin)-decreases water loss from the kidneys, constricts peripheral vessels ( increases blood pressure)
Diabetes insipidusposterior pituitary releases too little
ADH so too much water is lost. Person is always thirsty.
Fluid is not kept in the system. Can lead to severe dehydration and death. Treatment: synthetic ADH

 2. Oxytocin (quick childbirth) causes smooth muscles to contract and causes contraction of cells surrounding the secretory cells in mammary glandsoxytocin involved in child birth and breast feeding

 Adenohypophysis
 7 hormones
 1. TSH- Thyroid stimulating hormonecauses the release of thyroid hormone

 2. ACTH- adrenocorticotropic
Hormone- releases steroid hormones from the adrenal glands, especially those for glucose metabolism
(glucocorticoids)
 3. FSH- Follicle stimulating hormone.
In females causes egg development and promotes estrogen release. In males involved in sperm production

 4. LH- Lutenizing hormone. In females causes ovulation and promotes secretion of progesterone (preparation for pregnancy)
In males-called interstitial cell stimulating hormone (ICTH)-stimulates production of androgens (male hormones)
FSH and LH= gonadotroic hormones
(gonadotropins)-regulate the gonads

 5. Prolactin – involves in the development of mammary glands and milk production.
 6. GH- Growth Hormone- also known as human growth hormone. Especially targets skeletal muscle and cartilage cells.
 Pituitary Dwarfism-too little GH production
 Giantism- too much GH before puberty

 7. MSH-Melanocyte Stimulating Hormoneincreases production of skin pigment

GH prolactin
LH
F FSH
TSH
ACTH
MSH –skin

Parathyroid
Glands are not shown —found on the back of the Thyroid
Pineal Gland
Pituitary
Gland
Anterior Pituitary
Posterior Pituitary
Thyroid Gland
Thymus
Adrenal Gland
Pancreas
Ovary
Testes

 On the trachea (windpipe) under the thyroid cartilage
 Shaped like a butterfly
 Thyroid follicles release hormones into the bloodstream

 Thyroxine (T4)-causes gradual, long term increase in metablolism.
Accounts for 90% of thyroid secretions
 Triiodothyronine (T3) causes a strong, immediate increase in cellular metabolism short lasting

 Thyroid hormone functions:
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 use cellular metabolism and temperature, O2 and energy heart rate and blood pressure
Stimulate formation of RBCs
Stimulate activity of other endocrine tissues
Accelerate turnover of minerals in bones
Maintain respiratory sensitivity to changes in O
2 levels and CO
2
 Allows us to adapt to cold temperatures by metabolism and O2 consumption

 Hypothyroidismproduction of thyroid hormones
 Infants- leads to inadequate skeletal and nervous development, metabolic rate up to 40% below normal
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Later childhood-retards growth, delays puberty
Adultslethargic, can’t adjust to the cold
 Signs/Symptoms- dry skin, hair loss, slow reflexes, low body temp., intellectual slowness
 Treatment: synthetic thyroid hormones

 Hyperthyroidism-too much thyroid hormone
 Metabolic rate, perspiration, BP, and irregular heart beat, skin becomes flushed
 Restless, excitable, mood shifts
 Very little reserve energy and fatigues easily

 Goiter- enlarged thyroid gland
 Caused by increase of thyroid follicle size from low amounts of iodine in diet.

Salt has added iodine
 Graves Disease-excess thyroid activity leading to goiter, leading to symptoms of hyperthyroidism
 Bulging eyes
 More common in women- has genetic base
 Treatment: anti-thyroid drugs, removal or destruction of part of the thyroid(surgically or radioactive iodine)

 4 tiny glands —2 on each side of posterior thyroid
 Hormone = parathormone
 Regulates calcium concentration in blood and other body fluids (increases
Calcium concentration)

 Located in thoracic cavity behind sternum
 Gets larger until puberty, then atrophies
 Hormone —thymosin—important for normal immune system (T Cells)

 Cap on top of each kidney
 Each adrenal gland surrounded by a capsule
 2 parts:
 Adrenal Cortex
 Adrenal Medulla

 Outer part
 Stores lipids
 Produces many steroid hormones — adrenocorticosteroids or corticosteroids
 Necessary for life
 3 zones produce different types:
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Androgens, glucocorticoids (incl. cortisone and cortisol), mineralocorticoids

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1. Androgens —male hormones
2. Glucocorticoids —affect glucose metabolism
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 reduce inflammation throughout the body.
Example: Cortisol is a naturally occurring GC that is made by your adrenal glands, and works to regulate inflammation and other processes in your body.
Cushing’s Disease-overproduction of glucocorticoids leads to exaggerated response to stress, energy reserves moved around. Body fat changes-(moon face), muscles break down

 3.Mineralocorticoids-effect electrolyte composition of body fluids
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Hormone=aldosterone
Addison’s Disease-inadequate secretion of both glucocorticoids and mineralocorticoid
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Signs/symptoms: hypoglycemia, weakness, can’t mobilize energy reserves, can’t tolerate stress, can cause sharp and fatal fall in blood pressure, increased skin pigmentation

 Androgenital Syndrome-tumors that cause overproduction of androgens
 Women develop male secondary sex characteristics(hair patterns, muscle development, fat distribution
 Men it is called gynecomastia
(gyne=women,mast=breast). Development of female secondary sexual characteristics

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Inner part of adrenal glands
2 hormones —epinephrine (adrenalin) and norepinephrine (noradrenalin)
 Epinephrine
 75-80% of adrenal medulla secretions
 Increase cardiac activity, BP, glycogen breakdown, increases blood glucose. Causes adipose tissue to release lipids.
 Norepinephrine
 Causes blood vessels to constrict and heart rate to increase

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Used to increase muscle size and strength
Results:
 heart disease and heart attacks
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 liver disease stroke atrophy of testes and decreased sperm count decreased production of testosterone immune system depression
“roid rages” acne hair loss

 Lumpy, pink organ near the connection between the stomach and small intestine
 Both exocrine and endocrine functions

 Exocrine function
 Produces digestive enzymes
 Endocrine function
 Pancreatic islets (islets of
Langerhans) produce glucagon (alpha cells) and insulin (beta cells) which work together to regulate blood glucose
 Hypoglycemialow blood glucose

 Hyperglycemia = high blood glucose
 Leads to glycosuria and polyuria
 2 types of Diabetes mellitus
 Type 1 Diabetes = Insulin Dependent
Diabetes Mellitus (IDDM). Pancreas does not produce enough insulin
 Fatal without insulin therapy and dietary control
 Treatment: insulin injections plus diet and exercise

 Type 2 —Non Insulin Dependent Diabetes
Mellitus (NIDDM) —pancreas produces insulin, but peripheral tissues do not respond appropriately
 Treatment: weight loss, diet, oral medications
 Three times as common as
IDDM

 Complications
 Diabetic retinopathy- changes to blood vessels in the retina
 Diabetic nephropathy- kidney disease
 Diabetic neuropathy- disturbance to blood supply to neural
 Degenerative problems with cardiac circulation leading to heart attacks
 Peripheral vascular changes leading to decreased blood flow to the feet that can lead to sores and amputation

 Male
 Cells in testes produce androgens (testosterone is most important) which are responsible for:

Functional sperm
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Secondary sex characteristics and associated behaviors
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Protein synthesis
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Muscle growth

 Female:
 Ovarian follicles = place eggs (ova) develop
 FSH causes follicles to produce estrogens which are responsible for:
 Maturation of ova
 Growth of uterine lining
 Female secondary sex characteristics

 LH causes ovulation
 Corpus Luteum = follicle after ovulation
 Causes release mix of estrogens and progesterone
 Progesterone:
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Moves fertilized egg along fallopian tubes
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Prepares uterus for implantation
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Prepares mammary glands for lactation
In pregnancy —placenta works as endocrine gland

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Location = roof of thalamus
Hormone = melatonin —inhibits melanin production
 Melatonin production increases at night and decreases in daylight
 Involved in the establishment of circadian rhythms
 Seasonal Affective Disorder (SAD)

 Seasonal Affective Disorder (SAD)
 Happens in December through March when daylight hours are fewer and melatonin production increases
 More common in northern latitudes
 Causes depression, lethargy, decreased concentration, over eating, over sleeping, may be responsible for increased suicides

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Stress = any threat to homeostasis
General Adaptation Syndrome (GAS) — body’s response to stress regardless of source
 3 phases:
 Alarm phase
 Resistance phase
 Exhaustion phase

 3 Phases
 1 . Alarm phase- fast response directed by sympathetic division of ANS. Energy reserves mobilized (glucose) to get the body ready. Epinephrine is main hormone- fight or flight
 2. Resistance phase- Long term adjustments. Happens if stress lasts longer than a few hours (severe illness, severe anxiety, starvation, etc) Glucocorticoids are primary hormones although others are also involved. Lipid and protein reserves mobilized; glucose levels increase, stable glucose conserved for neural tissue

 3. Exhaustion phase- collapse of vital systems. Eventually homeostatic regulation breaks down. Nerve and muscle cells malfunction. Causes: exhaustion of lipid reserves, can’t produce glucocorticoids.
Vital organs are damaged. Death will happen without immediate steps taken to correct the problem

 Sex hormones at puberty
 More aggressive, assertive
 Mood swings
 Hormones can effect ability to learn, memory, intellect, emotional state
 Decrease of sex hormones at menopause and male climacteric
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 Mood swings
“Roid Rages”

 Few changes to hormones with aging except for reproductive hormones
(decrease)
 Tissues may become less responsive to hormones with age.