The Endocrine System

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The Endocrine System
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Hormones
Chemical substances secreted by endocrine
(ductless) glands. These chemicals are carried by
blood to their respective target cells.
Tend to control slow long-term activities in the
body.
What would be a slow long-term process?
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Primary Functions of Hormones

• Homeostasis
• Growth and Development
• Reproduction
• Energy Metabolism
• Behavior

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Chemical Composition of Hormones
Steroids Proteins/Polypeptides Amines
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Steroids
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Some Protein/Polypeptide Hormones
Glucagon Insulin Oxytocin ADH Calcitonin
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Amines
tyrosine
thyroxine
epinephrine
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Negative Feedback Loop
blood glucose low
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Biological Cycles
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Mechanism of Action on Target Cells
Water soluble hormone
response
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Mechanism of Action on Target Cells
lipid soluble hormone
response
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Tropic Versus Nontropic Hormones
Tropic hormones- stimulate the production and
secretion of hormones by other endocrine glands
ex. TSH Nontropic hormones- stimulates cellular
growth, metabolism, or other functions ex.
thyroxine
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Major Endocrine Organs
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Endocrine Organs of the Brain
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Pineal Gland
Produces melatonin (synthesized from seratonin, a
derivative of tryptophan)

• Secreted directly in CSF to blood
• High levels at night make us sleepy low level
  during day
• Pineal gland is stimulated by darkness and
  inhibited by light
• Function in regulating circadian rhythms (sleep,
  body temp, appetite) ? biological clock

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The Pituitary Gland
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Posterior Pituitary
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Hormones of the Posterior Pituitary
Antidiuretic Hormone (ADH) Oxytocin
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Oxytocin
( feedback) loop
oxytocin
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Anterior Pituitary
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Hormones of the Anterior Pituitary

• Growth Hormone (GH)
• Thyroid Stimulating Hormone (TSH)
• Adrenocorticotropic Hormone (ACTH)
• Gonadotropins (FSH, LH)
• Prolactin (PRL)
• Melanocyte-stimulating Hormone (MSH)

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Growth Hormone (GH)

• Stimulates protein building
• Stimulates cell growth (cell size and number),
  especially in muscle and bone.
• Also stimulates fat breakdown.

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GH Levels
sleep
awake
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Dwarfism
hyposecretion of GH
Little People Big World
Kenadie - worlds smallest girl due to primordial
dwarfism
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Gigantism
hypersecretion of GH
Bao Xishun, a 7ft 8.95in herdsman from Inner
Mongolia
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Acromegaly
hypersecretion of GH
7 ft 1 ¼ inches
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Thyroid-Stimulating Hormone (TSH)

• Acts on the thyroid gland, stimulating it to
  release T3 T4
• These thyroid hormones increase glucose
  catabolism and body heat production.
• Regulated via negative feedback

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Adrenocorticotropic Hormone (ACTH)

• Acts on the adrenal cortex, stimulating it to
  secrete glucocorticoids (e.g., cortisol).
• Helps make glucose from amino acids and fatty
  acids
• Regulated via negative feedback

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The Thyroid Gland
larynx
thyroid
trachea
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Thyroid Hormones
Thyroid gland selectively uptakes iodine to
produce T3 T4

• Thyroxine (T4)
• Triiodothyronine (T3)
• Both control metabolic rate and cellular
  oxidation
• Calcitonin - lowers blood Ca levels and causes
  Ca reabsorption in bone

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Goiter
Lack of iodine in diet hyposecretion of T3 T4
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hyposecretion of T3 T4
Cretinism
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Myxedemahyposecretion of T3 T4
After thyroid treatment
myxedema
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Exophthalmos- hyperthyroidism
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Parathyroid Glands
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Parathyroid Hormone (PTH)

• PTH release
• stimulates osteoclasts to reabsorb bone

Hyperparathyroidism- too much Ca drawn out of
bone could be due to tumor Hypoparathyroidism-
most often follow parathyroid gland trauma or
after removal of thyroid--- tetany, muscle
twitches, convulsions if untreated?respiratory
paralysis and death
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The Pancreas
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• Pancreas
• Regulates glucose uptake by cells
• Controlled via negative feedback insulin
  glucagon
• Blood sugar level 90 mg/mL

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Islets of Langerhans
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Insulin

• Produced by the ? cells of the Islets of
  Langerhan
• Catalyze oxidation of glucose for ATP production
• Lowers blood glucose levels by promoting
  transport of glucose into cells.
• Stimulates glucose uptake by the liver and
  muscle cells.
• Stimulates glycogen synthesis in the liver and
  muscle cells.
• Also stimulates amino acid uptake and protein
  synthesis of muscle tissue

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Glucagon

• Produced by the ? cells of the Islets of
  Langerhans
• Stimulates change of glycogen to glucose in the
  liver.
• Synthesis of glucose from lactic acid and non
  carbohydrate molecules such as fatty acids and
  amino acids
• Causes ? in blood glucose concentration

hypoglycemic- low blood sugar? deficient in
glucagon
   
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Diabetes Mellitus
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Type I Diabetes hyposecretion of
insulin insulin dependant juvenile onsetType
II Diabetes late onset (adult) insensitivity of
cells to insulin manage by exercise diet
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Symptoms (Type I)

• sugar in blood and urine
• urinate too often and produce too much urine
• Too thirsty
• Too hungry

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Type I (IDDM)

• Arteriosclerosis
• Cardiovascular problems
• Gangrene
• Eye problems
• Kidney damage

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Treatment

• Insulin replacement
• Pancreas transplant
• Pancreatic cell transplant
• Fetal pancreatic islet cell transplant

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Adrenal Glands
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(No Transcript)
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Hormones of the Adrenal Medulla

• Adrenalin (epinephrine) converts glycogen to
  glucose in liver
• Noradrenalin (norepinephrine) increases blood
  pressure
• (sympathetic nervous system)
• Corticosteroids? glucose levels)

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Hormones of the Adrenal Cortex

• Glucocorticoids- cortisol
• Decrease protein synthesis
• Increase release and use of fatty acids
• Stimulates the liver to produce glucose from non
  carbs
• Mineralcorticoids- aldosterone
• Stimulates cells in kidney to reabsorb Na from
  filtrate
• Increases water reabsorption in kidneys
• Increases blood pressure
• Sex Steroids- small amts (androgens)
• Onset of puberty
• Sex drive

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Cushings Syndrome
Hypersecretion of cortisone may be caused by an
ACTH releasing tumor in pituitary Symptoms
trunkal obesity and moon face, emotional
instability Treatment removal of adrenal gland
and hormone replacement
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Addisons Disease
Hyposecretion of glucocorticoids and mineral
corticoids Symptoms- wt loss, fatigue,
dizziness, changes in mood and personality, low
levels of plasma glucose and Na levels, high
levels of K Treatment- corticosteroid
replacement therapy
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Thymus
Located anterior to the heart Produces-
thymopoetin and thymosin? helps direct maturation
and specialization of T-lymphocytes (immunity)
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Gonads
Ovaries- produce estrogen and progesterone?respons
ible for maturation of the reproductive organs
and 2ndary sex characteristics in girls at
puberty
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Female Reproductive System
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Gonads
Testes- produce sperm and testosterone (initiates
maturation of male repro organs and 2ndary sex
characteristics in boys at puberty)
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INQUIRY

1. A disease in which too much T3 and T4 are
   produced.
2. The posterior pituitary produces which two
   hormones and what is their function?
3. What is acromegaly?
4. What organ does glucagon target?
5. The target tissue for lutenizing hormone is ____.
6. Where are epinephrine and norepinephrine
   produced?
7. If your adrenal cortex produced low levels of
   aldosterone, your urine would be _____?
8. What effect does parathyroid hormone have on your
   bones?