Some Review First
4 types of cell signal mechamisms
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Direct Contact- see table and page
127
Paracrine Signaling, message transmitted to neighboring cells
Synaptic signaling — neurotransmitters carry messages between nerve cells
* Endocrine signaling — hormones travel through circ system
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Focus of this presentation

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Polypeptides-short chains of aa’sinsulin and ADH (anti-diuretic hormone)
Glycoproteins-longer chains of aa’-
FSH and LH (from reproductive system)
Amines-from tyrosine and tryptophan-melanin and epinephrine
Steroids- derived from cholesterol
(inc. ring shape)-testosterone and progesterone

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Lipid or steroid hormones—diffuse into cell and trigger response
Protein or peptide hormones– use a second messenger system
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Hormone binds (1 st messenger)
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Triggers intracellular response via a G protein  c AMP (second messenger)

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Growth Hormone (GH) – Stimulates bone growth
Luteinizing Hormone (LH) – Stimulates ovaries and testes
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Named for corpus luteum
Follicle Stimulating Hormone(FSH)stimulates gonads to produce sperm and ova
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Named for follicle
Thyroid Stimulating Hormone (TSH)-
Stimulates thyroid gland

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Oxytocin – Stimulates contractions of uterus and mammary glands, associated with love and bonding.
Antidiuretic hormone (ADH) – retention of water by kidneys

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Ovaries
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Estrogen – stimulates uterine lining, development of primary and secondary female characteristics
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Progesterone – Uterine lining growth, helps maintain pregnancy
Testes
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Androgens (testosterone) – sperm production (after stimulation by FSH), secondary sex characteristics

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Thyroxine– controls metabolic rate
Calcitonin– lowers blood calcium levels (deposits Ca++ in bone)
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Hypothyroidism may lead to goiter
Hyperthyroidism may lead to protrusion of the eyes (bulging) and Grave’s Disease
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Both problems make it difficult to control metabolic rate

Cretinism
Hyposecretion of thyroxine in childhood

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Parathyroid Hormone (PTH) Raises blood calcium level (removes Ca ++ from bone)
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Hypoparathyroidism - Bones become weakened
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Osteoporosis—same outcome, but for a variety of reasons

PANCREAS-
Islets of Langerhans
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Insulin – β cells – lowers blood glucose levels
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Glucagon – α cells -raises blood glucose levels
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Read Analyzing Functions of Pancreas
(Dog Studies)

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Type 1 – Hyposecretion of Insulin,
Insulin Dependent diabetes
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Type 2 – Cellular response to insulin is decreased
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Associated with obesity, strong diet correlation

Uncontrolled diabetes can lead to damage of many systems. Some problems may be kidney disease, nervous system problems, blindness, peripheral vascular disease.

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Adrenal Medulla – Catecholamines Epinephrine and Norepinephrine raises blood sugar by incr. breakdown of glycogen in liver, short term stress response
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Adrenal Cortex --Glucocorticoids -- raise blood sugar levels, long term stress response
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Overproduction—Cushing’s Disease (breakdown of proteins and unusual fat distribution)
Long term stress has adverse effects on many systems

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Thymosin– Stimulates T lymphocytes

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Melatonin - Biorhythms –Day and
Night Cycles

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(Look at anatomy transparency 14.20)
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Negative feedback--Return to baseline- balance see-saw
Positive feedback--Continued unbalance

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Antagonistic hormones have opposite effects. They work together to maintain homeostasis.
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Ex: Insulin and Glucagon,
PTH and Calcitonin

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Glands may stimulate (or inhibit) other glands
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See Thyroxine secretion page 1004
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See testes and anterior pituitary page
1071

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See page 102 in ABLE