Endocrine System

Question 1

What are the major differences between the endocrine and nervous system?

Answer 1

the endocrine system;
- transmits ligands
- exhibits longer reaction times
- has longer lasting effects

Question 2

What are the types of circulating hormones?

Answer 2

• steroids
• biogenic amines
• proteins

Question 3

What are local hormones?

Answer 3

signaling molecules that don’t circulate in blood

Question 4

what are Eicosanoids?

Answer 4

a type of local hormone formed from fatty acids within phospholipid bilayer of membrane

Question 5

What are the effects of eicosanoids?

Answer 5

• autocrine stimulation: effects on the same cell where messenger was formed
• paracrine stimulation:
  effects on neighboring cells

Question 6

What are the advantages of lipid soluble hormones using carrier molecules?

Answer 6

• do not dissolve readily in blood
• carriers are water soluble proteins made by liver
• carriers protect hormones from early destruction

Question 7

True or false, only lipid soluble hormones use carrier molecules

Answer 7

false, some water soluble hormones use carrier proteins to prolong their life

Question 8

What two factors determine the concentration of a hormone?

Answer 8

how fast it is synthesized and eliminated

Question 9

How does hormone elimination occur?

Answer 9

occurs in multiple ways:
- enzymatic degradation in liver cells
- removal from blood via kidney excretion or target cell uptake

Question 10

What is a hormone’s half life?

Answer 10

time necessary to reduce a hormone’s concentration to half of its original level

Question 11

How does the half life of water soluble hormones compare to that of steroid hormones?

Answer 11

• water soluble hormones generally have a short half life
• steroid hormones generally have a long half life

Question 12

What allows for lipid soluble hormones to diffuse across target cell membrane

Answer 12

they are small, nonpolar, and lipophillic

Question 13

what happens once a lipid soluble hormone enters its target cell

Answer 13

• binds to receptor and forms hormone-receptor complex
• complex binds to a hormone response element of DNA

Question 14

Why can’t water soluble hormones diffuse through membrane?

Answer 14

they are polar

Question 15

where are water soluble hormone receptors

Answer 15

on cell membrane

Question 16

Describe the signal transduction pathway of a water soluble hormone

Answer 16

1. hormone is first messenger and binds to receptor
2. binding actives a G protein
3. G protein activation causes activation of a membrane enzyme
4. activated enzyme catalyzes the formation of a second messenger

Question 17

What are the actions of water soluble hormones?

Answer 17

• enzymes can be activated or inhibited
• growth can be stimulated
• cellular secretions can be released
• membrane permeability can be changed
• muscles can be contracted or relaxed

Question 18

what are the advantages of a signal transduction pathway?

Answer 18

• signal is amplified at each enzymatic step
• there are many places to regulate pathway activities

Question 19

What determines the target cells response to a particular hormone?

Answer 19

• number of hormone receptors
• interactions among other hormone actions

Question 20

What structure is the pituitary gland attached to and how so?

Answer 20

connected to hypothalamus by infundibulum

Question 21

How do the size and tissue of each part of the pituitary compare?

Answer 21

• posterior pituitary is smaller, neural part
• anterior pituitary is large, glandular part

Question 22

What are the components of the posterior pituitary?

Answer 22

composed of pars nervosa(lobe) and infundibulum

Question 23

What are the three sections of the anterior pituitary?

Answer 23

• pars distalis: large anterior rounded portion
• pars tuberalis: thin wrapping around infundibulum
• pars intermedia: scant region between other two

Question 24

the posterior pituitary is the storage and release site for which hormones?

Answer 24

oxytocin and antidiuretic hormone (both are made in hypothalamus)

Question 25

What is the relationship between the hypothalamus and the anterior pituitary?

Answer 25

the hypothalamus stimulates anterior pituitary to release its hormones by secreting regulatory hormones

Question 26

what are the two types of regulatory proteins secreted by the hypothalamus

Answer 26

1. releasing hormones: increase secretion of anterior p hormones 2. inhibiting hormones: decrease secretion of anterior p hormones

Question 27

What are the hormones released by the anterior pituitary gland?

Answer 27

- thyroid stimulating hormone (TSH) - prolactin - adrenocorticotropic hormone (ACTH) - follicle-stimulating hormone and leutenizing hormone (FSH and LH) - growth hormone (GH)

Question 28

What are the functions of growth hormone?

Answer 28

- stimulation of linear growth at epiphyseal plate - hypertrophy of muscle - release of nutrients from storage into blood

Question 29

what hormone stimulates the releases of GH?

Answer 29

growth hormone releasing hormone (GHRH)

Question 30

What cells does GH target?

Answer 30

hepatocytes which release insulin like growth factors (IGFs)

Question 31

What cells have GH receptor cells

Answer 31

all body cells have receptors for GH, IGF, or both

Question 32

How do GH and IGFs work?

Answer 32

cause adipose cells to release nutrients - increases levels of glycerol and fatty acids in blood

Question 33

What is the thyroid gland composed of?

Answer 33

composed of microscopic follicles - follicular and parafollicular cells

Question 34

What hormones do follicular cells produce?

Answer 34

thyroid hormone

Question 35

what hormone do parafollicular cells produce

Answer 35

calcitonin

Question 36

What is the difference between T3 and T4?

Answer 36

- thyroid gland produces more T4 but T3 is more active form - most target cells convert T4 to T3

Question 37

What does thyroid hormone do?

Answer 37

increases metabolic rate and protein synthesis in targets, also fosters energy production

Question 38

describe the negative feedback loop for TH

Answer 38

- Increases in TH cause decreases in its release o TH inhibits release of TRH from hypothalamus o TH inhibits release of TSH from anterior pituitary o TH causes release of growth hormone inhibiting hormone further inhibiting TSH release

Question 39

describe the anatomy of the adrenal medulla

Answer 39

- forms inner core of each adrenal gland - red-brown color due to extensive blood vessels - releases epinephrine and norepinephrine with sympathetic stimulation

Question 40

describe the anatomy of the adrenal cortex

Answer 40

- synthesizes over 25 corticosteroids - yellow color due to lipids within cells - 3 regions producing different steroid hormones

Question 41

From superficial to deep, list the three regions of the adrenal cortex

Answer 41

- zona glomerulosa - zona fasciculata - zone reticularis

Question 42

What are the hormones of the adrenal cortex

Answer 42

- mineralocorticoids: hormones that regulate electrolyte levels - glucocorticoids: hormones that regulate blood sugar - gonadocorticoids: sex hormones

Question 43

What is the function of cortisol

Answer 43

increase nutrient levels in blood

Question 44

what regulates the release of cortisol?

Answer 44

the hypothalamic-pituitary-adrenal axis

Question 45

Describe the process of how cortisol is released

Answer 45

- stress, late stages of sleep, low cortisol levels stimulate hypothalamus to release CRH - CRH stimulates ant. pituitary to release ACTH ACTH stimulates adrenal cortex to release cortisol - cortisol travels through blood attached to carrier proteins - cortisol diffuses through target cell's membrane & binds to intracellular receptor - cortisol causes target cell to increase blood nutrient levels

Question 46

what is corticosterone used a treatment for?

Answer 46

inflammation

Question 47

how does corticosterone treat inflammation?

Answer 47

it inhibits inflammatory agents and supresses immune system

Question 48

What causes Cushing syndrome?

Answer 48

excessive glucocorticoid

Question 49

what causes Addison disease?

Answer 49

form of adrenal insuffiency when adrenal glands fail

Question 50

What are the three stages of a stress response?

Answer 50

- alarm reaction - stage of resistance - stage of exhaustion

Question 51

What endocrine organ also has exocrine functions

Answer 51

the pancreas

Question 52

What is the function of acini cells in the pancreas?

Answer 52

generate exocrine secretions for digestion

Question 53

What are pancreatic islets?

Answer 53

clusters of endocrine cells in pancreas

Question 54

what do alpha cells secrete?

Answer 54

glucagon

Question 55

what do beta cells secrete?

Answer 55

insulin

Question 56

What is the main function of the pancreatic hormones?

Answer 56

help maintain blood glucose

Question 57

What is the function of insulin

Answer 57

lowers blood glucose

Question 58

How does insulin lower blood glucose?

Answer 58

- hepatocytes remove glucose from blood; store it as glycogen - adipose cell decrease fatty acid levels in blood - most body cells increase nutrient uptake in response to insulin

Question 59

What causes type 1 diabetes?

Answer 59

absent or diminished release of insulin by pancreas; requires daily insulin injections

Question 60

What causes type 2 diabetes?

Answer 60

decreased insulin release or insulin effectiveness usually due to obesity

Question 61

What is the effect of glucagon?

Answer 61

raises blood glucose

Question 62

How does glucagon raise blood glucose?

Answer 62

acts through membrane receptors and 2nd messenger causing body cells to release stored nutrients into blood

Question 63

What hormone does the pineal gland secrete?

Answer 63

melatonin

Question 64

What does the parathyroid gland do?

Answer 64

helps regulate blood calcium