Endocrine System

Question 1

Endocrine system

Answer 1

-Produces hormones to help maintain homeostasis, regulate reproduction and development

Question 2

hormone

Answer 2

Chemical messenger produced in one part of the body that affect target cells in another part of the body

Question 3

how are hormones released?

Answer 3

-Endocrine glands have no ducts- they

Secrete hormones directly into blood or interstitial fluid–fluid that surrounds cells

Question 4

-Hormones belong to one of four groups:

Answer 4

oFatty acid derivatives
Ex- prostaglandins

oSteroids
Ex- cortisol, testosterone, estrogen, progesterone

oPeptides–chains of amino acids
Ex- oxytocin, ADH

oModified amino acids
Ex- thyroid hormone, epinephrine/adrenaline

Question 5

target cells

Answer 5

-Hormones only has affect once it reaches the target cells-
Contain receptors that recognize and bind hormones.

Question 6

how do hormones trigger target cells?

Answer 6

Hormone can pass through cell membrane and bind to a receptor protein on the nucleus (Usually steroid hormones, which are lipid soluble)
or
Hormones can bind to the receptor on the cell membrane and cause formation of second messenger, like cAMP, which activates intracellular events (Usually peptide hormones, which cannot pass through the membrane)
-Hormones usually act by negative feedback, in which hormone triggers a response that counteracts the changed condition, restoring homeostasis

Question 7

Hypothalamus

Answer 7

oLocated in forebrain

oCenter of homeostatic control of the internal environment- monitors external and internal conditions

oDetermines what actions are necessary to maintain homeostasis

oSecretes hormones that are releasers or inhibitors of hormones from the pituitary

Question 8

Pituitary gland

Answer 8

• is connected to hypothalamus at the base

oNeurosecretory cells link pituitary to hypothalamus- structured like neurons but release hormones into blood instead of neurotransmitters

oKnown as “master gland” because some of its hormones control the production of hormones in other glands

o2 halves, or lobes: anterior and posterior lobe

Question 9

Posterior pituitary

Answer 9

secretes hormones produced by the hypothalamus

Produce ADH (antidiuretic hormone), which acts in the kidneys, helping absorb more water in the body

Produces oxytocin, which triggers uterine contraction and milk production

Question 10

Anterior pituitary

Answer 10

secretes its own hormones, including tropic hormones

Question 11

tropic hormones-

Answer 11

target other endocrine glands

Question 12

Adrenocorticotropic Hormone (ACTH)-

Answer 12

Anterior pituitary, stimulates secretions from adrenal glands

Question 13

Thyroid stimulating hormone (TSH)-

Answer 13

Anterior pituitary, stimulates thyroid gland to release hormones

Question 14

Follicle-stimulating hormone (FSH)-

Answer 14

Anterior pituitary, role in gamete formation

Question 15

Luteinizing Hormone (LH)-

Answer 15

Anterior pituitary, role in gamete formation

Question 16

Prolactin (PRL)-

Answer 16

Anterior pituitary, stimulates milk production in mammary glands

Question 17

Growth Hormone (GH)-

Answer 17

Anterior pituitary, stimulates growth of bones and muscles

Question 18

Thyroid

Answer 18

oLocated in neck region, in front of trachea and below larynx

oSecretes T4 (thyroxin) and T3 (triiodothyronine)

oEssential for normal growth and development

oRegulated by negative feedback system:

Question 19

negative feedback system–thyroid

Answer 19

When conc of thyroid hormones rise above normal, anterior pituitary secretes less thyroid stimulating hormone

When conc of thyroid hormones are low, anterior pituitary secretes more thyroid stimulating hormone

Question 20

oMalfunctions of thyroid gland:

Answer 20

Hypothyroidism

Hyperthyroidism

Goiter

Question 21

Hypothyroidism

Answer 21

reduced thyroid function, results in little energy, slow, confused, tired

Question 22

Hyperthyroidism

Answer 22

increased thyroid function, results in increased thyroid function, nervous, irritable

Question 23

Goiter

Answer 23

abnormally enlarged thyroid gland, either due to hyposecretion of hormones (can be caused by iodine deficiency) or hypersecretion of hormones . remove w radioactive iodine or surgery

Question 24

-Parathyroid glands:

Answer 24

Located in connective tissue surrounding the thyroid gland
Secretes parathyroid hormone (PTH)- helps regulate calcium levels in blood
Stimulates calcium release from bones when calcium levels in blood are low

Question 25

Calcitonin

Answer 25

Calcitonin, which is release from thyroid gland, works antagonistically to parathyroid hormone
Inhibits removal of calcium from bones when calcium levels in blood are high

Question 26

-Pancreas:

Answer 26

oClusters of cells called Islets of Langerhans are composed of 2 types of cells:
Beta cells- secrete insulin

Alpha cells- secrete gluacagon

Question 27

Insulin

Answer 27

Stimulates cells of liver and other organs to take up glucose from blood when blood glucose levels are high
Ex- after eating
Glucose is either used right away as fuel or stored as glycogen
This lowers the blood glucose level

Question 28

Glucagon

Answer 28

Stimulates liver cells to convert glycogen into glucose when blood glucose levels are low
Ex- a few hours after eating
This raises the blood glucose level

Question 29

oDiabetes:

Answer 29

Characterized by high glucose conc
Type I- antibodies destroy beta cells, leading to insulin deficiency
Type II- develops gradually, insulin receptors on target cells do not bind insulin (can be caused by obesity)

Question 30

-Adrenal glands:

Answer 30

oPaired gland that lie on upper ends of kidneys

oConsist of two portions-

Adrenal medulla (center)
Adrenal cortex (outer)

Question 31

Adrenal cortex

Answer 31

Glucocorticoid, ex- Cortisol- stimulates increase in blood glucose level

Mineralcorticoid, ex- Aldosterone- stimulates kidney to take in more salt, increasing blood volume

Sex hormone precursors, ex- Androgens- converts into testosterone or estradiol

Question 32

Adrenal medulla

Answer 32

Secretes epinephrine (adrenaline) and norepinephrine (noradrenaline)

During stress or anxiety, sympathetic nervous system stimulates secretion of both hormones

Question 33

Ovary

Answer 33

secretes estrogens,(targets gen and uterus, stimulates development of uterine lining + develop and maintain sex characteristics in female)
progesterone, (uterus and breast, stimulates development of uterine lining)

Question 34

Testis

Answer 34

Testosterone–general, reproductive structures, develop and maintain sex characteristics in male and promotes spermatogenesis

Question 35

10 glands

Answer 35

hypothalamus, pituitary, pineal, thyroid, parathyroids, thymus,adrenal, pancreas, ovary/testis