The endocrine system
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The Endocrine System. 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?. Primary Functions of Hormones.

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Hormones
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?


Primary functions of hormones
Primary Functions of Hormones

  • Homeostasis

  • Growth and Development

  • Reproduction

  • Energy Metabolism

  • Behavior


Chemical composition of hormones
Chemical Composition of Hormones

Steroids

Proteins/Polypeptides

Amines



Some protein polypeptide hormones
Some Protein/Polypeptide Hormones

Glucagon

Insulin

Oxytocin

ADH

Calcitonin


Amines
Amines

tyrosine

thyroxine

epinephrine


Negative feedback loop

stimulates

glucose release from liver

glucagon from pancreas

stimulates

inhibits

blood glucose high

Negative Feedback Loop

blood glucose low



Mechanism of action on target cells

hormones

endocrine cell

receptor protein

target cell

Mechanism of Action on Target Cells

Water soluble hormone

response


Mechanism of action on target cells1

hormones

endocrine cell

intracellular receptor

target cell

Mechanism of Action on Target Cells

lipid soluble hormone

response


Tropic versus nontropic hormones
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


Major endocrine organs

hypothalamus

pineal gland

pituitary gland

thyroid gland

thymus gland

parathyroid glands

adrenal glands

pancreas

ovaries

testes

Major Endocrine Organs


Endocrine organs of the brain

pineal gland

hypothalamus

pituitary gland

Endocrine Organs of the Brain


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




Hormones of the posterior pituitary
Hormones of the Posterior Pituitary

Antidiuretic Hormone (ADH)

Oxytocin


Oxytocin

(+ feedback)

loop

oxytocin



Hormones of the anterior pituitary
Hormones of the Anterior Pituitary

  • Growth Hormone (GH)

  • Thyroid Stimulating Hormone (TSH)

  • Adrenocorticotropic Hormone (ACTH)

  • Gonadotropins (FSH, LH)

  • Prolactin (PRL)

  • Melanocyte-stimulating Hormone (MSH)


Growth hormone gh
Growth Hormone (GH)

  • Stimulates protein building

  • Stimulates cell growth (cell size and number), especially in muscle and bone.

  • Also stimulates fat breakdown.


Gh levels

strenuous exercise

GH Levels

sleep

awake


Dwarfism

hyposecretion of GH

Little People Big World

Kenadie - worlds smallest girl due to primordial dwarfism


Gigantism
Gigantism

hypersecretion of GH

Bao Xishun, a 7ft 8.95in herdsman from Inner Mongolia


Acromegaly
Acromegaly

hypersecretion of GH

7 ft 1 ¼ inches


Thyroid stimulating hormone tsh
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


Adrenocorticotropic hormone acth
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


The thyroid gland
The Thyroid Gland

larynx

thyroid

trachea


Thyroid hormones
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


Goiter
Goiter

Lack of iodine in diet

hyposecretion of T3 & T4



Myxedema hyposecretion of t3 t4
Myxedemahyposecretion of T3 & T4

After thyroid treatment

myxedema


Exophthalmos hyperthyroidism
Exophthalmos-hyperthyroidism



Parathyroid hormone pth
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



  • Pancreas:

  • Regulates glucose uptake by cells

  • Controlled via negative feedback: insulin & glucagon

  • Blood sugar level: 90 mg/mL


Islets of langerhans

capillaries

alpha cells

beta cells

Islets of Langerhans


Insulin
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


Glucagon
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



Type I Diabeteshyposecretion of insulin insulin dependant juvenile onsetType II Diabeteslate onset (adult) insensitivity of cells to insulin manage by exercise & diet


Symptoms (Type I):

  • sugar in blood and urine

  • urinate too often and produce too much urine

  • Too thirsty

  • Too hungry


Type I (IDDM):

  • Arteriosclerosis

  • Cardiovascular problems

  • Gangrene

  • Eye problems

  • Kidney damage


Treatment:

  • Insulin replacement

  • Pancreas transplant

  • Pancreatic cell transplant

  • Fetal pancreatic islet cell transplant



Hormones of the adrenal medulla
Hormones of the Adrenal Medulla

  • Adrenalin (epinephrine): converts glycogen to glucose in liver

  • Noradrenalin(norepinephrine): increases blood pressure

  • (sympathetic nervous system)

    • Corticosteroids: glucose levels)


  • Hormones of the adrenal cortex
    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 carb’s

    • 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


    Cushing s syndrome
    Cushing’s 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


    Addison s disease
    Addison’s 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


    Thymus

    Located anterior to the heart

    Produces- thymopoetin and thymosin helps direct maturation and specialization of T-lymphocytes (immunity)


    Gonads

    Ovaries- produce estrogen and progesteroneresponsible for maturation of the reproductive organs and 2ndary sex characteristics in girls at puberty



    Gonads

    Testes- produce sperm and testosterone (initiates maturation of male repro organs and 2ndary sex characteristics in boys at puberty)


    INQUIRY

    • A disease in which too much T3 and T4 are produced.

    • The posterior pituitary produces which two hormones and what is their function?

    • What is acromegaly?

    • What organ does glucagon target?

    • The target tissue for lutenizing hormone is ____.

    • Where are epinephrine and norepinephrine produced?

    • If your adrenal cortex produced low levels of aldosterone, your urine would be _____?

    • What effect does parathyroid hormone have on your bones?


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