 Endocrine system and the nervous system often work together to bring about homeostasis  Both use specific communication methods and affect specific target organs

 Coordinates body activities (gamete production and release)  Helps maintain homeostasis  Growth and development  Regulates metabolic processes  Helps body respond to trauma or stress

 Exocrine glands ◦ Secretions released into ducts opening onto an epithelial surface  Endocrine glands ◦ Ductless organs that secrete directly into the bloodstream  Endocrine glands release hormones

 Molecules that have an effect on specific organs  Only cells with specific receptors for the hormone respond to that hormone  Called target cells, and the organs that contain them are called target organs

What are hormones, and why do we need them?

Where in the body are hormones produced? a.pituitary b.pancreas c.reproductive organs d.thyroid e.all of the above

Where in the body are hormones produced? e.all of the above

Which gland is consider the “master” gland? a.gonads b.adrenal gland c.hypothalamus d.pituitary gland e.estrogen gland

Which gland was once considered the “master” gland? Which one might be the real boss? d.pituitary gland/Hypothalamus

The pancreas _______. a.secretes cortisol into the blood b.secretes epinephrine c.secretes the hormones insulin and glucagon into the blood d.does none of the above

The pancreas _______. c.secretes the hormones insulin and glucagon into the blood

 A stimulus starts a process, and eventually either the hormone that is secreted or a product of its effects causes the process to slow down or turn off  Example: blood sugar too high (stimulus) the pancreas releases insulin which lowers blood sugar (response)

Figure 1–4  The response of the effector negates the stimulus

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 Accelerates the original process, either to ensure that the pathway continues to run or to speed up its activities

 The response of the effector reinforces the stimulus Figure 1–5

 Pituitary  Thyroid  Parathyroid  Adrenal  Pineal  Thymus  Pancreas  Testes  Ovariew

 Broken up into anterior and posterior

 Growth Hormone (GH)  Thyroid-stimulating Hormone (TSH)  Adrenocorticotropic Hormone (ACTH)  Melanocyte-stimulating Hormone (MSH)  Lutenizing Hormone (LH)  Follicle-stimulating Hormone (FSH)  Prolactin (PRL)

 Antidiuretic Hormone (ADH)  Oxytocin (OT)

Located in the throat  T3  T4  Calcitonin (CT)

Located on top of thyroid gland  Parathyroid Hormone (PTH)

 Sits on top of each kidney  Divided into two parts ◦ Adrenal cortex – outside ◦ Adrenal medulla - inside

 Aldosterone  Cortisol Epinephrine (adrenaline)

Melatonin

Thymosin

 Insulin  Glucagon

Male gonads Androgen (testosterone)

Female gonads  Estrogen  progesterone

 Stimulate synthesis of enzymes or structural proteins  Increase or decrease rate of synthesis  Turn existing enzyme or membrane channel “on” or “off”

 The Pancreas has cells that regulate glucose levels in the blood. ◦ Alpha cells:  produce glucagon  Glucagon makes blood glucose levels rise by breaking down glycogen and fats where it is stored. ◦ Beta cells:  secrete insulin  Insulin takes excess glucose out of the blood by storing it away in the liver and muscles as glycogen.

 Glucose=sugar used for energy we get from food we eat.  Glycogen=long chains of glucose stored in the liver.  Glucagon=Hormone made by the pancreas to put glucose into the blood when it is low.

 What happens if blood sugar levels fall? Explain.

 Steroid/lipid-soluble hormones can diffuse directly through the cell membrane.  Nonlipid-soluble hormones must use a second messenger system to cause cellular changes. ◦ cAMP ◦ cGMP

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1. GH 2. Thyroid hormones 3. Insulin 4. PTH 5. Calcitriol 6. Reproductive hormones

 In children: ◦ supports muscular and skeletal development  In adults: ◦ maintains normal blood glucose concentrations ◦ mobilizes lipid reserves

 If absent during fetal development or for first year: ◦ nervous system fails to develop normally ◦ mental retardation results  If T 4 concentrations decline before puberty: ◦ normal skeletal development will not continue

 Allows passage of glucose and amino acids across cell membranes

 Promote absorption of calcium salts for deposition in bone  Inadequate levels causes weak and flexible bones

 Androgens in males, estrogens in females  Stimulate cell growth and differentiation in target tissues  Produce gender-related differences in: ◦ skeletal proportions ◦ secondary sex characteristics

 Can alter intellectual capabilities, memory, learning, and emotional states  Affect behavior when endocrine glands are oversecreting or undersecreting

 Also called stress response  How bodies respond to stress-causing factors  Is divided into 3 phases: 1.alarm phase 2.resistance phase 3.exhaustion phase

 Is an immediate response to stress  Is directed by ANS  Energy reserves mobilized (glucose)  “Fight or flight” responses  Dominant hormone is epinephrine (adrenaline)

1. Increased mental alertness 2. Increased energy consumption 3. Mobilization of energy reserves (glycogen and lipids) 4. Circulation changes: ◦ increased blood flow to skeletal muscles ◦ decreased blood flow to skin, kidneys, and digestive organs 5. Drastic reduction in digestion and urine production 6. Increased sweat gland secretion 7. Increases in blood pressure, heart rate, and respiratory rate

 Entered if stress lasts longer than few hours  Dominant hormones are glucocorticoids  Energy demands remain high  Glycogen reserves nearly exhausted after several hours of stress

1. Mobilize remaining lipid and protein reserves 2. Conserve glucose for neural tissues 3. Elevate and stabilize blood glucose concentrations 4. Conserve salts, water, and loss of K +, H +

 Begins when homeostatic regulation breaks down  Failure of 1 or more organ systems will prove fatal  Mineral imbalance