Ch 49 Endocrine Regulation

Question 1

• Endocrine glands, cells, tissues that secrete hormones (chemical signals)
– regulate physiological processes
– endocrine glands
• Signals a wide range of target cell types
– unlike nerve stimuli

Answer 1

The Endocrine System

Question 2

Specialized cells; no ducts

• unlike exocrine glands

Answer 2

Endocrine glands

Question 3

Most endocrine responses are ____
– but long-lasting
– unlike responses to nerve stimuli

Answer 3

Slow

Question 4

• Uses endocrine glands (glands without ducts)
– often discrete specialize organs
– secrete hormones into interstitial fluid or blood

Answer 4

Classical Endocrine Signaling

Question 5

Hormones transported by _____
– lipid soluble hormones bound to plasma proteins
• others (water soluble) dissolved in plasma
– move into interstitial fluid and bind with specific receptors of specific target cells

Answer 5

Blood

Question 6

• hormone (or other signal molecule) diffuses through interstitial fluid to act on nearby target cells
• functions include control of smooth muscle, fever reactions

Answer 6

Paracrine Signaling

Question 7

• A hormone acts on the very cells that produced it

* Example: estrogen can stimulate some cells to increase estrogen production

Answer 7

Autocrine Signaling

Question 8

• Neurons secrete neurohormones
– may also serve as neurotransmitters
• Transported by blood
• Link between Nervous and Endocrine System
• Primary endocrine signals in invertebrates

Answer 8

Neuroendocrine Signaling

Question 9

• Small, lipid-soluble hormones
– Steroid hormones, thyroid hormones
• Pass through plasma membrane
– combine with receptors in target cell
• Hormone–receptor complex 
– activates or represses transcription of messenger RNA coding for specific proteins (e.g. enzymes)

Answer 9

Intracellular Signaling

Question 10

• Hydrophilic peptide (protein) hormones
– do not enter target cells
• Combine with receptors on plasma membrane of target cells
– G protein-linked receptors: use cyclic AMP as second messenger
– Enzyme-linked receptors: bind hormones outside cell and have direct enzymatic functions inside
• Receptor transduces extracellular hormone signal into intracellular signal

Answer 10

Signal Transduction

Question 11

Regulates many processes:

• growth and development
• reproduction
• salt and fluid balance
• many aspects of metabolism
• behavior

Answer 11

Human Endocrine System

Question 12

Hypothalamus

• integrates nervous and endocrine regulation
• regulates activity of pituitary gland

Answer 12

Close relationship with Nervous System

Question 13

• Hypothalamus
– produces neurohormones released by posterior lobe of pituitary
– Posterior lobe actually develops from neural cells
– Oxytocin
– Antidiuretic hormone (ADH)

Answer 13

Posterior Lobe of Pituitary

Question 14

• stimulates contraction of uterus

* stimulates release of milk

Answer 14

Oxytocin

Question 15

• stimulates reabsorption of water (in kidneys)

Answer 15

Antidiuretic hormone (ADH)

Question 16

• Secretes	 and receives signals like typical endocrine gland 
– prolactin
– melanocyte-stimulating hormones
– growth hormone (HGH)
– several	tropic	hormones
(stimulate	other	endocrine glands)

Answer 16

Anterior Lobe of Pituitary

Question 17

Stimulates milk production

Answer 17

Prolactin

Question 18

Skin pigments
• also suppress appetite
• regulate energy, body weight

Answer 18

Melanocyte-stimulating hormones

Question 19

• stimulates body growth (protein synthesis)

Answer 19

Growth hormone (HGH)

Question 20

• clusters of cells throughout pancreas
– secrete insulin and glucagon
– regulated directly by glucose concentration

Answer 20

Islets of Langerhans in pancreas

Question 21

– lowers blood glucose

Answer 21

Insulin

Question 22

– raises blood glucose

Answer 22

Glucagon

Question 23

The effects of insulin and glucagon oppose each other to maintain blood glucose.
Brain cells require a continuous supply.

Answer 23

Regulation of Glucose

Question 24

• Includes Type 1 and Type 2 diabetes
• Results in
– decreased use of glucose but high blood glucose
– increased fat mobilization to make glucose
– increased protein use to make glucose
– electrolyte imbalance: dehydration

Answer 24

Diabetes Mellitus

Question 25

Insulin deficiency caused by autoimmune disorder in which antibodies mark insulin producing cells for destruction.

Answer 25

Type 1

Question 26

Insulin resistance gradually develops

• cells fail to take up and use glucose from blood

Answer 26

Type 2

Question 27

• Impaired glucose tolerance results in
– delayed insulin response
– hypersecretion of insulin (overreaction) 
• Glucose concentration falls
– causing drowsiness or unconsciousness

Answer 27

Hypoglycemia

Question 28

Too much insulin
– can be caused by overdose injection or tumor
– deprives brain of fuel
– loss of coordination, convulsions, death

Answer 28

Insulin Shock