Chapter 42- Endocrine System

Question 1

What is a hormone? Where is it secreted into and how does it travel to different types of the body?

Answer 1

Regulatory chemical that is secreted into extracellular fluid and carried by the blood

Question 2

What are the 2 basic hormone characteristics?

Answer 2

1. Must be sufficiently complex to convey regulatory information to their target cells
2. Must be adequately stable to resist destruction before
   reaching their target cells

Question 3

What are the 5 mechanisms for signaling? describe each

Answer 3

1) classical endocrine - systemic
2) paracrine regulators - allow cells of organ to regulate eachother and do not travel in blood
3) autocrine regulators - self
4) neurohormone - released from neruons and travel in blood
5) pheromones - chemicals released into the environment to communicate among individuals of a single species, Not involved in normal metabolic regulation within an animal

Question 4

What is the difference between neurotransmitters and neurohormones?

Answer 4

neurotransmitters act locally typically in the synapse while neurohormones are carried by blood. However, both can travel in the blood and act as a hormone.

Question 5

What is norepinephrine? Is it a neurotransmitters or neurohormones?

Answer 5

It’s a neurotransmitter that coordinates the activity of heart, liver, and blood vessels during stress

Question 6

What is antidiuretic hormone? Is it a neurotransmitters or neurohormones?

Answer 6

It’s a neurohormone secreted by neurons of the brain

Question 7

What are the 4 classes of signaling molecules?

Answer 7

amine, steroid, peptide, and fatty acid

Question 8

What signaling mechanisms do amine hormones use?

Answer 8

classical and neuroendocrine

Question 9

What are most amine hormones based on?

Answer 9

tyrosine

Question 10

What are amine hormones?

Answer 10

Most are hydrophilic molecules, which diffuse readily into the ECF and bind to receptors at the cell surface

Question 11

What is thryoxine?

Answer 11

hydrophobic amine hormone secreted by the thyroid gland – it passes through the plasma membrane and binds to a receptor inside the target cell

Question 12

What signaling mechanisms do peptide hormones use?

Answer 12

classical and neuroendocrine, may also act in paracrine and autocrine signaling

Question 13

What is the structure of peptide hormones? Examples

Answer 13

Made of amino acid chains (3 to >200 amino acids), Some have carbohydrate groups attached. They are released into the blood or ECF. ex) growth factors

Question 14

What signaling mechanisms do steriod hormones use?

Answer 14

classical

Question 15

What are all hydrophobic molecules derived from?

Answer 15

cholesterol

Question 16

What is the structure of steroid hormones? examples?

Answer 16

Combine with hydrophilic carrier proteins to form water soluble complexes that can diffuse through the ECF and
enter the bloodstream.
On contacting a cell, the hormone is released from its carrier protein, passes through the plasma membrane of the target cell, and binds to internal receptors in the nucleus or cytoplasm
ex) aldosterone, cortisol,
and the sex hormones

Question 17

What signaling mechanisms do fatty acid hormones use?

Answer 17

paracrine and autocrine

Question 18

What are prostaglandins? (3 functions)

Answer 18

1) local regulator fatty acid hormone, which can Increase contractions of smooth muscle cells, particularly in the uterus.
2) Induce contraction or relaxation of smooth
muscle cells in blood vessels and air passages in
the lungs.
3) Intensify pain and inflammation in injured cells

Question 19

What are the two functional classes of hormones?

Answer 19

lipophilic fat soluble and hydrophilic water soluble

Question 20

What are lipophilic fat soluble hormones? (4)

Answer 20

nonpolar, steroid and thyroid hormones, travel on transport proteins in blood, bind to intracellular receptors, long active period

Question 21

What are hydrophilic water soluble hormones? (4)

Answer 21

all other hormones, freely soluble in blood, bind to extracellular receptors, act over a brief time period

Question 22

What is amplicfication?

Answer 22

each activated protein activates a larger number of

proteins for the next step in the pathway, small amounts of hormone can created a large effect

Question 23

What does structures do the endocrine system include? 9 main glands?

Answer 23

all organs and tissues that secrete hormones

thyroid gland, parathyroid glands, adrenal medulla, adrenal cortex, gonads, pancreas, pineal gland, pituitary, hypothalamus

Question 24

What is the pituitary gland also known as? location? structure?

Answer 24

aka hypophysis, hangs by a stalk from the hypothalamus, made of anterior pituitary (adeno-hypophysis) and posterior pituitary (neuro-hypophysis)

Question 25

Describe the pituitary gland origin?

Answer 25

diagram on 18

Question 26

What is the appearance of the anterior pituitary?

Answer 26

glandular

Question 27

What is the appearance of the posterior pituitary? key 2 facts?

Answer 27

fibrous, different embryonic origins, different hormones

Question 28

What are the 7 essential hormones that the anterior pituitary produces? what type of hormones are they?

Answer 28

1) Thyroid Stimulating Hormome (TSH) 2) Adrenocorticotropic hormone (ACTH) 3) Melanocyte-stimulating hormone (MSH) 4) Growth hormone (GH) 5) Prolactin (PRL) 6) Follicle Stimulating Hormone (FSH) 7) Luetinizing Hormone (LH) most are tropic hormones or tropins

Question 29

What are tropic hormones or tropins?

Answer 29

Act on other endocrine glands

Question 30

What are 4 non-tropic hormones? functions?

Answer 30

1) Melanocyte-stimulating hormone (MSH) - Stimulates melanin production in melanocytes, little production in adults 2) Growth hormone (GH) - stimulates cell division, protein synthesis, and bone growth in children and adolescents, thereby causing body growth. GH also stimulates protein synthesis and cell division in adults 3) Prolactin (PRL) - milk synthesis post-parteum 4) Endorphins - peptide hormones produced by the hypothalamus and pituitary that help control pain

Question 31

What two hormones are produced by the posterior pituitary? function?

Answer 31

1) Anti-diuretic Hormone (ADH) - stimulates kidney cells to absorb more water from urine, thereby increasing the volume of the blood 2) Oxytocin - stimulates the ejection of milk from the mammary glands of a nursing mother, Males have it as well

Question 32

What are goiters caused by?

Answer 32

lack of iodine in the diet

Question 33

What are the 3 hormones secreted by the thyroid gland? function?

Answer 33

1) thyroxine (T4) - precursor converted in liver to T3 2) triiodothyronine (T3) - More active form Thyroid hormones bind to nuclear receptors 3) Calcitonin - Peptide hormone, Stimulates the uptake of calcium (Ca2+) into bones– lowering blood Ca2+ levels. Appears less important in the day-to-day regulation of Ca2+ levels in adult humans

Question 34

What are the parathyroid glands? Hormone and function?

Answer 34

◦ 4 small glands attached to the thyroid ◦ Produce parathyroid hormone (PTH) - stimulates osteoclasts to release Ca2+ into blood, stimulates kidneys to reabsorb Ca2+ from urine, Vitamin D activated by a PTH controlled enzyme, stimulates the intestinal absorption of Ca2+

Question 35

Structure of Adrenal Glands?

Answer 35

1) medulla (inner portion) | 2) cortex (outer portion)

Question 36

What is the function of the medulla?

Answer 36

Stimulated via the sympathetic nervous system Secretes the catecholamines: epinephrine and norepinephrine

Question 37

What is the function of the cortex?

Answer 37

stimulated by ACTH and secretes corticosteroids (glucocorticoids and aldosterone (mineralocorticoid))

Question 38

What are glucocorticoids?

Answer 38

long-term stress response which effects lipid and carbohydrate metabolism, immune system, and damage repair.

Question 39

What are catecholamine hormones?

Answer 39

short-term stress response which effects cardiovascular system, carbohydrate and lipid metabolism, central nervous system.

Question 40

What is the structure of the pancreas?

Answer 40

◦ Connected to the duodenum of the small intestine by the pancreatic duct ◦ Islets of Langerhans are scattered clusters of cells throughout the pancreas that produce hormones based on blood glucose levels

Question 41

What two functions does the pancreas have?

Answer 41

exocrine and endocrine

Question 42

What is insulin secreted by? function?

Answer 42

◦ Secreted by beta (β) cells of the islets ◦ Stimulates cellular uptake of blood glucose and its storage as glycogen in the liver and muscle cells, or as fat in fat cells

Question 43

What is glucagon secreted by? function?

Answer 43

◦ Secreted by alpha (α) cells of the islets | ◦ Promotes the hydrolysis of glycogen in the liver and fat in adipose tissue

Question 44

What is diabetes mellitus?

Answer 44

cannot take up glucose from blood

Question 45

What is type 1 diabetes?

Answer 45

◦ Individuals lack insulin-secreting β cells ◦ Treated by daily injections of insulin insulin-dependent

Question 46

What is type 2 diabetes?

Answer 46

more common, low number of insulin receptors, treated by diet and exercise noninsulin-dependent

Question 47

Structure and function of pineal gland?

Answer 47

◦ Located in the roof of the third ventricle of the brain | ◦ Secretes hormone melatonin

Question 48

What is the role of melatonin?

Answer 48

◦ Synchronizes various body processes to a circadian rhythm | ◦ Secretion of melatonin activated in the dark

Question 49

What are the gonads? function?

Answer 49

Ovaries and testes in vertebrates. Produce sex steroids that regulate reproductive development

Question 50

What are the female hormones?

Answer 50

estrogen and progesterone

Question 51

What are the male hormones?

Answer 51

androgens, testosterone and its derivatives

Question 52

In annelids (worms), arthropods, and mollusks, endocrine cells and glands produce hormones that regulate?

Answer 52

reproduction, water balance, heart rate, and sugar levels

Question 53

What are the 3 major hormones that regulate molting and metamorphosis in insects?

Answer 53

Prothoracicotropic hormone (PTTH), Ecdysone, Juvenile hormone (JH)

Question 54

What does Prothoracicotropic hormone (PTTH) do?

Answer 54

a peptide hormone secreted by neurosecretory neurons stimulates the prothoracic glands to release ecdysone.

Question 55

What does Ecdysone do?

Answer 55

a steroid hormone secreted by prothoracic glands promotes growth of a new exoskeleton under the old one and stimulates the release of other hormones that lead to the molt.

Question 56

Locatoion and structure of Juvenile hormone (JH)?

Answer 56

a terpenoid secreted by the corpora allata, a pair of glands just behind the brain

Question 57

What happens when JH is high? low?

Answer 57

If JH is high, the molt produces a larger larva – if it is low, the molt leads to pupation and the emergence of the adult

Question 58

What happens after the adult emerges from the pupa?

Answer 58

JH levels rise again and help trigger full mature sexual behavior.

Question 59

How does molting in crustaceans work? hormones involved?

Answer 59

◦ Before growth reaches the stage at which the exoskeleton is shed, moltinhibiting hormone (MIH), a peptide neurohormone secreted by a gland in the eye stalks, inhibits ecdysone secretion ◦ As body size increases to the point requiring a molt, MIH secretion is inhibited, ecdysone secretion increases, and the molt is initiated

Question 60

What type of neurons release neurohormones?

Answer 60

neurosecretory