Ch 49

Question 1

endocrine regulation

Answer 1

hormone signaling within the body

Question 2

What type of signal are hormones?

Answer 2

Chemical signals, hormones are the way cells communicate and talk to each other

Question 3

How are hormones moved throughout the body?

Answer 3

they are secreted into the interstitial fluid and typically transported by the blood

Question 4

What do endocrine glands do?

Answer 4

secrete and produce hormones

Question 5

hormones

Answer 5

chemical messengers that regulate many physiological processes, hormones excite or stimulate changes in specific tissues

Question 6

endocrine glands vs exocrine glands

Answer 6

NOT THE SAME THING, endocrine secrete hormones within interstitial fluid or blood, exocrine release their secretions into ducts

Question 7

target cells

Answer 7

the cells influenced by a particular hormone, target cells may be in another endocrine gland or in an entirely different type of organ, target cells may be located far from the endocrine gland (ex. thyroid gland secretes hormones that stimulate metabolism in tissues throughout the body)

Question 8

Which responds more quickly, the endocrine system or the nervous system?

Answer 8

The nervous system responds more quickly but the results of the endocrine system are longer lasting

Question 9

How are hormones removed from the blood?

Answer 9

by the liver which inactivates them and by the kidneys which excrete them

Question 10

How is most endocrine action regulated?

Answer 10

by negative feedback systems which are regulatory systems in which a change in some steady state triggers a response that counteracts, or reverses, the change, restoring homeostasis

Question 11

How does the body respond when the concentration of calcium in the blood is below the homeostatic level?

Answer 11

a decrease in calcium concentration in the plasma signals the parathyroid glands to release more parathyroid hormone, this hormone increases the concentration of calcium in the blood, when the calcium concentration rises above normal limits, the parathyroid glands slow their output of hormone, both responses are negative feedback systems, an increase in calcium concentration results in decreased released of parathyroid hormone, whereas a decrease in calcium leads to increased hormone secretion, in each case the response counteracts the inappropriate change, restoring the steady state

Question 12

How do the nervous and endocrine systems work together?

Answer 12

the nervous system responds rapidly to stimuli by transmitting electrical and chemical signals, neurons signal other neurons, muscle cells, and gland cells, including endocrine cells, the nervous system helps regulate many endocrine responses, the endocrine system will then release certain hormones that could potentially effect which neurotransmitters are released

Question 13

What are four major chemical groups to which hormones are assigned? Give two examples for each group.

Answer 13

fatty acid derivatives: prostaglandins and the juvenile hormones of insects; steroids: the molting hormone of insects, anything from the adrenal cortex, testis, ovary and placenta such as testosterone, or estrogen; amino acid derivatives: thyroid hormones such as epinephrine and norepinephrine; peptides/proteins: glucagon and antidiuretic hormone (ADH)

Question 14

What is the basic structure of each of the four major chemical groups of hormones?

Answer 14

fatty acids: have long hydrocarbon chains, steroids: have a lot of rings of carbon and hydrogen, amino acids: their names end with -ine, peptides: peptide means protein, amino acids hooked in short chains, are specialized for moving through blood

Question 15

classical endocrine signaling

Answer 15

hormones are secreted by endocrine glands and are transported by the blood to target cells

Question 16

neuroendocrine signaling

Answer 16

neuroendocrine cells produce neurohormones that are transported dwn axons and released into the interstitial fluid, they typically diffuse into capillaries and are transported by the blood, invertebrate endocrine systems are largely neuroendocrine, in vertebrates the hypothalamus produces neurohormones that link the nervous system with the pituitary gland, an endocrine gland that secretes several hormones, this is almost exactly like classical except the only difference is which cell makes it (neuron)

Question 17

autocrine regulation (signaling)

Answer 17

auto=self, the cell signals itself

Question 18

paracrine regulation (signaling)

Answer 18

para=nearby, it secretes a hormone into the interstitial fluid to a neighboring cell, the cell doesn’t get picked up by the blood,

Question 19

local regulator

Answer 19

a signaling molecule that diffuses through the interstitial fluid and acts on nearby cells, most endocrinologists include at least certain local regulators as hormones

Question 20

Steroid and thyroid hormones

Answer 20

both are hydrophobic which means that they can pass through the plasma membrane and get into the cell, once in the cell they combine with receptors within the target cell, the hormone-receptor complex may activate or repress transcription of messenger RNA coding for specific proteins

Question 21

How does a hormone change the action of a cell?

Answer 21

by changing the genes it uses, some parts of the cell’s DNA aren’t used until a hormone ‘turns it on’ inside the cell

Question 22

peptide hormones

Answer 22

are hydrophilic which means they cannot enter the target cells, since they can’t enter the cell they combine with receptors on the plasma membrane of target cells rather than inside of the cell, many of these hormones bind to G protein-linked receptors or receptor tyrosine kinases, they act via signal transduction, hormones are primary messengers in this case that affect secondary messengers, since these hormones can’t get into the cell themselves the second messengers alter the activity within the cell

Question 23

kinases and phosphotase

Answer 23

Kinases are enzymes that phosphorylate (add phosphate groups to things), Phosphotase is an enzyme that removes phosphate groups from things

Question 24

Examples of second messengers used with peptide hormones

Answer 24

cyclic AMP (cAMP), calcium ions, kinases, and phospho-proteins

Question 25

Receptor tyrosine kinases

Answer 25

enzyme-linked receptors, bind growth factors including insulin and nerve growth factors, receptor itself activates second messengers

Question 26

signal amplification

Answer 26

occurs as each hormone receptor complex stimulates the production of second messenger molecules, second messengers activate protein kinase molecules that activate protein molecules

Question 27

growth factors

Answer 27

stimulate cell division and normal development in specific types of cells

Question 28

local regulators as hormones

Answer 28

some local regulators are considered hormones, they use autocrine or paracrine signaling, local regulators include growth factors, peptides that stimulate cell division and development, and prostaglandins, a group of local hormones that help regulate many metabolic processes

Question 29

What are hormone receptors?

Answer 29

large proteins, or glycoproteins

Question 30

Receptor down-regulation and receptor up-regulation

Answer 30

down-regulation decreases the sensitivity of target cells to the hormone, so it dampens the hormone’s ability to carry out its function, up-regulation occurs when the concentration of a particular hormone is too low, increasing the number of receptors on the plasma membrane increases the hormone’s effect on the cell

Question 31

Hormone-receptor complex

Answer 31

formed when specific protein receptors in the cytoplasm or in the nucleus bind with the hormone

Question 32

Two main types of cell-surface receptors that bind hormones

Answer 32

G protein-linked receptors and enzyme-linked receptors

Question 33

What are the steps involved in a hydrophobic molecule changing a cell’s processes?

Answer 33

1: hormone molecules pass through plasma membrane, 2: hormone moves through cytosol, 3: hormone passes through nuclear envelope and binds with receptor in nucleus, 4: activated receptor is transcription factor that binds to and activates (or represses) specific genes, 5: specific proteins are synthesized, 6: proteins alter cell processes

Question 34

G protein-linked receptors

Answer 34

transmembrane proteins that initiate signal transduction, they convert an extracellular hormone signal into an intracellular signal that affects some cell process, the hormone does not enter the cell, rather it serves as the first messenger and relays information to a second messenger which then signals effector molecules that carry out the action, G protein-linked receptors activate G proteins

Question 35

G proteins

Answer 35

activated by G protein-linked receptors, are a group of integral regulatory proteins, the G indicates that they bind guanosine triphosphate (GTP) which, like ATP, is an important molecule in energy reactions

Question 36

What is the process by which hydrophilic hormones change cell processes?

Answer 36

1) peptide hormone (first messenger) binds with G protein-linked receptors in plasma membrane of target cell, G protein is activated and activates the enzyme adenylyl cyclase, 2) adenylyl cyclase converts ATP to cAMP (second messenger), 3) cAMP relays signal and activates protein kinase or some other protein that leads to a response, some cell activity is altered, look on page 1059, figure 49-5 for help with this

Question 37

enzyme-linked receptors

Answer 37

are transmembrane proteins with a hormone-binding site outside the cell and an enzyme site inside the cell, these receptors are not linked to G proteins, they function directly as enzymes or are directly linked to enzymes, most enzyme-linked receptors are receptor tyrosine kinases that bind growth factors and other signal molecules, including insulin, when the receptor is activated, it phosphorylates the amino acid tyrosine in specific signaling proteins inside the cell

Question 38

Functions of hormones in invertebrates

Answer 38

help regulate: metabolism, growth and development, regeneration, molting, metamorphosis, reproduction and behavior

Question 39

How do hormones regulate insect development?

Answer 39

hormones control development in insects, when stimulated by some environmental factor, neuroendocrine cells in the insect brain secrete brain hormone (BH), which is transported down axons and stored in the paired corpora cardiac, when released from the corpora cardiac, BH stimulates the prothoracic glands, endocrine glands in the prothorax, to produce molting hormone (MH), also called ecdysone, molting hormone, a steroid hormone, stimulates growth and molting; in the immature insect, paired indocrine glands called corpora allata secrete juvenile hormone (JH), this hormone suppresses metamorphosis at each larval molt so that the insect increases in size while remaining in its immature state, after the molt, the insect is still in a larval stage, when the concentration of JH decreases below some critical level, metamorphosis occurs and the insect is transformed into a pupa, in the absence of JH the pupa molts and becomes an adult, the nervous system regulates the secretory activity of the corpora allata and the amount of JH decreases with successive molts

Question 40

What is the function of juvenile hormone in insects?

Answer 40

it suppresses metamorphosis at each larval molt

Question 41

What are the endocrine glands that are present in vertebrates?

Answer 41

hypothalamus, posterior pituitary, anterior pituitary, thyroid gland, parathyroid gland, pancreas, adrenal medulla, adrenal cortex, pineal gland, ovary, and testis

Question 42

hyposecretion vs hypersecretion

Answer 42

hyposecretion is an abnormally reduced output of hormones, if this occurs the target cells are deprived of needed stimulation; hypersecretion is an abnormally increased output of hormones, if this occurs the target cells may be overstimulated, any of these abnormalities leads to loss of homeostasis

Question 43

What organ is most endocrine activity controlled by, either directly or indirectly?

Answer 43

the hypothalamus

Question 44

What organ links the endocrine and nervous systems both anatomically and physiologically?

Answer 44

The hypothalamus

Question 45

What gland is connected to the hypothalamus?

Answer 45

the pituitary gland is connected to the hypothalamus by the pituitary stalk

Question 46

pituitary gland

Answer 46

because secretions of the pituitary gland control the activities of several other endocrine glands, biologists refer to it as the master gland of the body, the pituitary gland produces six peptide hormones that exert far-reaching influence over growth, metabolism, reproduction, and many other body activities, the human pituitary gland consists of an anterior and posterior lobe, but in some vertebrates an intermediate lobe is present

Question 47

posterior lobe of the pituitary gland

Answer 47

secretes oxytocin and antidiuretic hormone (ADH), these two hormones are PRODUCED by cells in the hypothalamus but SECRETED by the posterior lobe, these hormones are enclosed within vesicles and transported down the axons of the neuroendocrine cells into the posterior lobe, they are then stored in the axon terminals until the neuron is stimulated, then they are released and diffuse into surrounding capillaries

Question 48

function of antidiuretic hormone (ADH), where it comes from, and where it's target tissue is

Answer 48

ADH stimulates reabsorption of water in the kidneys, it comes from the posterior pituitary and it's target tissue is the kidneys

Question 49

oxytocin: function, gland, and target tissue

Answer 49

oxytocin is released from the posterior pituitary, it's target tissues are either the uterus or the mammary glands, oxytocin stimulates contraction when its target tissue is the uterus, towards the end of pregnancy the oxytocin concentration in the blood rises which stimulates strong contractions of the uterus that are needed to expel a baby, oxytocin is sometimes administered clinically to initiate or speed labor; after birth, when an infant sucks on its mother's breast, sensory neurons signal the pituitary to release oxytocin, the hormone stimulates the ejection of milk into ducts, making it available to nursing infants; because oxytocin stimulates the uterus to contract, breastfeeding promotes the recovery of the uterus to nonpregnant size

Question 50

releasing and inhibiting hormones: what gland secretes them, what is their target tissue, and what are their functions?

Answer 50

releasing and inhibiting hormones are released from the hypothalamus, their target tissue is the anterior lobe of the pituitary, and the regulate the secretion of hormones by the anterior pituitary

Question 51

growth hormone (GH): gland it's secreted from, target tissue, and function

Answer 51

secreted by the anterior pituitary gland, it's target tissue is 'general', and it stimulates the growth of skeleton and muscle

Question 52

prolactin: gland that secretes it, target tissue, and function

Answer 52

secreted by the anterior pituitary, it's target tissue is mammary glands, and it stimulates milk production

Question 53

melanocyte-stimulating hormones (MSH): gland that secretes it, target tissues, and function

Answer 53

secreted by the anterior pituitary gland, it's target tissue are pigment cells in skin, and it's function is to stimulate melanin production in some animals, but in humans it's function is to help regulate food intake

Question 54

thyroid-stimulating hormone (TSH): gland that secretes it, target tissue, and function

Answer 54

secreted by the anterior pituitary gland, it's target tissue is the thyroid gland, it stimulates the secretion of thyroid hormones and helps regulate bone remodeling

Question 55

adrenocorticotropic hormone (ACTH): gland that secretes it, target tissue, and function

Answer 55

secreted by the anterior pituitary gland, it's target tissue is the adrenal cortex, it's function is to stimulate the secretion of adrenal cortical hormones

Question 56

gonadotropic hormones: gland that secretes it, target tissue, and function

Answer 56

secreted by the anterior pituitary gland, it's target tissue is the gonads, and it's function is to stimulate gonad function and growth

Question 57

thyroxine (T4) and triiodothyronine (T3): gland that secretes it, target tissue, and function

Answer 57

secreted by the thyroid gland, it's target tissue is 'general', and it's function is to stimulate metabolic rate and regulate energy metabolism

Question 58

calcitonin: gland that secretes it, target tissue, and function

Answer 58

secreted by the thyroid gland, it's target tissue is bone, and it's function is to lower the blood calcium level; calcitonin "tones up" bones

Question 59

parathyroid hormone: gland that secretes it, target tissue, and function

Answer 59

secreted by the parathyroid glands, it's target tissue is bone, kidneys, and digestive tract, it's function is to regulate blood calcium levels

Question 60

insulin: gland that secretes it, target tissue, and function

Answer 60

secreted by the pancreas, it's target tissue is 'general' tissue, and it's function is to lower blood glucose concentration

Question 61

glucagon: gland that secretes it, target tissue, and function

Answer 61

secreted by the pancreas, it's target tissue is liver and adipose tissue, it's function is to raise blood glucose concentration

Question 62

epinephrine and norepinephrine: gland that secretes it, target tissue, and function

Answer 62

secreted by the adrenal medulla, it's target tissue is muscle, blood vessels, liver, and adipose tissue, it's function is to help the body cope with stress, increase metabolic rate, raise blood glucose levels, and increase heart rate and blood pressure

Question 63

mineralocorticoids: gland that secretes it, target tissue, and function

Answer 63

secreted by the adrenal cortex, it's target tissue is the kidney tubules, and it's function is to maintain sodium and potassium balance

Question 64

glucocortoids: gland that secretes it, target tissue, and functions

Answer 64

secreted by the adrenal cortex, it's target tissue is general tissue, and it's function is to help the body cope with long-term stress and raise blood glucose levels

Question 65

melatonin: gland that secretes it, target tissue, and function

Answer 65

secreted by the pineal gland, it's target tissue is the hypothalamus, and it's function is to regulate biological rhythms

Question 66

estrogens: gland that secretes it, target tissue, and function

Answer 66

secreted by the ovary, it's target tissue is general tissues and the uterus, it's function is to develop and maintain sex characteristics in females and to stimulate the growth of uterine lining

Question 67

progesterone: gland that secretes it, target tissue, and function

Answer 67

secreted by the ovary, it's target tissue is the uterus and the breasts, it's function is to stimulate the development of uterine lining

Question 68

testosterone: gland that secretes it, target tissue, and function

Answer 68

secreted by the testis, it's target tissue is general tissues and reproductive structures, it's function is to develop and maintain sex characteristics in males and to promote spermatogenesis

Question 69

What results from hyposecretion of growth hormone? Hypersecretion?

Answer 69

hyposecretion of growth hormone results in pituitary dwarfism, and hypersecretion results in gigantism if malfunction occurs in childhood and acromegaly if it occurs in adulthood

Question 70

What results from hyposecretion of thyroid hormones? Hypersecretion?

Answer 70

hyposecretion results in cretinism (in children), myxedema, a condition of prounounced adult hypothyroidism, dietary iodine deficiency leads to hyposecretion and goiter; hypersecretion leads to hyperthyroidism, increased metabolic rate, nervousness, irritability, goiter, and Graves' disease

Question 71

What results from hyposecretion of parathyroid hormone? Hypersecretion?

Answer 71

hyposecretion results in spontaneous discharge of nerves, spasms, tetany, and death; hypersecretion results in weak and brittle bones, and kidney stones

Question 72

What results from hyposecretion of insulin? Hypersecretion?

Answer 72

hyposecretion of insulin results in diabetes mellitus; hypersecretion results in hypoglycemia

Question 73

What results from hyposecretion of hormones of the adrenal cortex? Hypersecretion?

Answer 73

hyposecretion results in Addison's disease; hypersecretion results in Cushing's Syndrome

Question 74

What hormone acts antagonistically to parathyroid hormone?

Answer 74

Calcitonin, which is secreted by the thyroid

Question 75

Where are the islets of Langerhans? What do they do?

Answer 75

the islets of Langerhans are located on the pancreas, they secrete insulin and glucagon

Question 76

How does insulin work in the bloodstream? Glucagon?

Answer 76

insulin converts glucose in the bloodstream to glycogen in the cells, glucagon works oppositely by converting glycogen to glucose

Question 77

What forms estrogen/testosterone in the opposite sex?

Answer 77

the adrenal cortex

Question 78

What is the adrenal medulla made up of?

Answer 78

neural tissue

Question 79

What's the difference in location of the adrenal cortex and the adrenal medulla?

Answer 79

the adrenal cortex is the outer part of the adrenal gland whereas the adrenal medulla is on the inside

Question 80

What do islets of Langerhans consist of?

Answer 80

beta cells, which secrete insulin, and alpha cells, which secrete glucagon

Question 81

Where are receptor molecules found?

Answer 81

in the nucleus, cell membrane, and cytoplasm of target cells; they are NOT found in interstitial fluid

Question 82

Which hormone exerts antagonistic action to insulin?

Answer 82

glucagon (both are made in Islets of Langerhans)