Exercise 18

Endocrine SystemGlucometer

Portland Community CollegeBI 232

The endocrine system

• Diverse collection of organs and tissues that contain endocrine glands.

• Glands secrete chemicals called hormones into blood capillaries

• Hormones are transported to target cells at a distant location

• Hormone binds to a specific receptor and the cell responds to message.

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Endocrine and Exocrine

• Exocrine glands secrete substances into ducts, which transport the secretions internal cavities of organs or to surface of the skin.

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Neuroendocrine effect

• The endocrine system operates in conjunction with the nervous system to maintain homeostasis and to ensure that bodily functions are carried out efficiently.

• Nerve impulses can affect the release of hormones and hormones can regulate nerve impulses

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Endocrine Organs in Head

• Pineal gland Secrets:• Melatonin

• Involved in circadian rhythms

• Day melatonin, Night melatonin

• Produces sleepiness

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Endocrine Organs in Head• Hypothalamus produces a number

of releasing hormones and inhibiting hormones.

• Stored in posterior pituitary• ADH (antidiuretic hormone)

• Reduces urine output by increasing water reabsorption in the kidney

• Plays small role in blood pressure regulation

• Oxytocin• Causes uterine contractions in

labor• Causes milk let down in lactating

mothers

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Endocrine Organs in Head• Hypophysis• ACTH (adrenocorticotropic

hormone)• Regulates the activity of the

cortex of the adrenal gland• TSH (thyroid stimulating hormone)

• Stimulates production and release of thyroid hormone

• GH (growth hormone)• Stimulates growth of bones,

cartilage, muscle• Timing and amount released

determines body size

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Endocrine Organs in Head• PRL (prolactin)

• Stimulates breast development• Promotes and maintains

lactation after childbirth• FSH (follicle stimulating hormone)

• Causes formation of ovarian follicles and stimulates them to produce estrogen

• Stimulates sperm development in men

• LH (luteinizing hormone)• Initiates ovulation, maintains

corpus luteum• Regulates testosterone

production in males

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PituitaryHistology

Endocrine Organs in Neck• Thyroid gland secretes:• Thyroid Hormone

• Regulates metabolic rate of the entire body

• Important in development of the nervous system

• Calcitonin• Decreases bone reabsorption,

lowering serum calcium levels• PTH (parathyroid hormone)

• Increases serum calcium • Decreases serum phosphorus

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Thyroid Histology

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Thyroid Histology

• Follicular cells produce the colloid (contains precursors to thyroid hormone)

• Parafollicular cells secrete calcitonin

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Parathyroid Histology

Endocrine organs in thoracic • Heart: If blood volume is

elevated above normal, cardiac muscle cells in the heart was secrete natriuretic peptides.

• Act on the kidneys to promote the loss of sodium ions and water.

• The thymus gland produces hormones called thymosins that promote maturation of T-lymphocytes that coordinate the body’s immune response.

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Endocrine Organs located in abdominopelvic cavity

• Pancreas secretes:• Insulin

• Released in response to high blood sugar

• Increases cellular absorption of glucose

• Increases rate of lipogenesis and formation of glycogen in the liver

• Glucagon• Released in response to low

blood sugar• Elevates blood glucose levels

by promoting the breakdown of glycogen.

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Pancreas

•Acinar cells secrete digestive enzymes (exocrine)

•Islet cells secrete insulin (beta cells) and glucagon (alpha cells)

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Adrenal Glands

Endocrine Organs located in abdominopelvic cavity

• Adrenal glands secrete:• Glucocorticoids (Cortisone)

• Released in response to stress• Increases formation of glucose

from protein and fat breakdown

• Decreases inflammation• Aldosterone

• Increases blood volume by causing kidneys to retain sodium (where sodium goes water goes too) in exchange for potassium

• Increased blood volume will increase blood pressure

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Endocrine Organs located in abdominopelvic cavity

• Androgens• Are male sex hormones that

are produced in small quantities and converted to estrogens (female sex hormones) when they enter the blood

• Epinephrine & Norepinephrine• Fight or flight response• Increase heart rate, increase

skeletal muscle blood flow, decrease skin blood flow

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Hormones from the Kidneys

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• Erythropoietin• Stimulates RBC

production

• Calcitriol• Stimulates calcium and

phosphate absorption

• Stimulates calcium release from bone

• Inhibits PTH secretion

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Adrenal Histology

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Adrenal Cortex

Zona Glomerulosa:Aldosterone

Zona Fasiculata:Glucocorticoids (Cortisone)

Zona Reticularis:Androgens

Gonads

• Ovaries in females produce estrogens

• Testes in males produce testosterone

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Ovary

• Have an outer cortex that contains ovarian follicles at various stages of development.

• Each follicle contains a developing egg cell called an oocyte

• Inner medulla is a region of loose connective tissue

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Testis

• Tunica albuginea is a fibrous connective tissue covering.

• Connective tissue partitions derived from the tunica albuginea divide the testes into lobules

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Testes

• Each lobule of the testes are three or four seminiferous tubules.

• Collectively these cells are called spermatogenic cells.

• The interstitial areas contain the interstitial (Leydig) cells.

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Diabetes

• Type 1: Insulin Dependent Diabetes

• AKA: juvenile diabetes

• Caused by a lack of insulin

• Autoimmune disorder • Immune system destroys beta cells in the pancreas

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Diabetes

• Type 2: Non-Insulin Dependent

• Caused by an insensitivity of cells to insulin.

• Diabetes mellitus marked by hyperglycemia urine production (polyuria) thirst (polydipsia) eating (polyphagia)

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Diagnosing Diabetes Mellitus

• Normal blood glucose levels: 70-100 mg/dl• Diabetes mellitus:

• A fasting glucose level above 140 mg/dl on two separate occasions, or

• A blood sugar over 200 mg/dl 2 hours after oral glucose tolerance test with 75gm of glucose

• Impaired Glucose Tolerance (Pre-Diabetes)• A fasting glucose level between 100-126 mg/dl on two

separate occasions, or

• A blood sugar between 140-200 mg/dl 2 hours after oral glucose tolerance test with 75gm of glucose

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The End