ch 11.7- endocrine system

Question 1

what are the types of hormones

Answer 1

peptide
steroid
amino acid

Question 2

peptide hormones- how are they produced

Answer 2

produced in the rough ER and made of amino acids connected by peptide bonds

Question 3

how do peptide hormones work

Answer 3

bind to cell surface receptors bc they are water soluble and cant pass through membrane

indirect stimulation- signal transmitted thorugh ligand gated ion channels or intracellular secondary messengers

Question 4

ligant gated ion channel

Answer 4

change shape upon binding to peptide hormones allowing ions to flow across the membrane of the cell

no second messengers

Question 5

second messenger systm

Answer 5

used for peptide hoomrones and allows for quick and immediate physiological changes

signal amplification

Question 6

seconadary messengers example

Answer 6

cAMP
IP3
DAG
Ca2+

Question 7

IP3/DAG pathway

Answer 7

Here, IP3 binds
to calcium channels on the endoplasmic reticulum,
triggering the activation and opening of these
calcium channels, releasing calcium ions into the
cytosol.

Question 8

GPCRs

Answer 8

are cell
surface receptors that can initiate a secondary
messenger response after binding to a peptide
hormone extracellularly. A G protein is coupled to
the receptor and dissociates into subunits after
activation. These subunits then act upon intracellular
second messengers to propagate the signal.

Question 9

steroid hormone synthesis

Answer 9

Produced in the smooth ER and made up
of a fused four-ring structure. All steroid hormones
are derived from cholesterol.

Question 10

what are some examples of steroid hormones

Answer 10

All hormones produced by the adrenal
cortex (glucocorticoids, mineralocorticoids,
androgenic steroids) and reproductive organs
(progesterone, testosterone, estrogen).

Question 11

how do steroid hormones work

Answer 11

Lipid-soluble (lipophilic). Therefore, require a
protein carrier to travel through the bloodstream, but
can freely cross the cell membrane. Bind to receptors
either in the cytoplasm or the nucleus to form
hormone-receptor complexes that bind to DNA, and
influence gene transcription. This process is known as
direct stimulation. Steroid hormones cause slow and
gradual physiological changes.

Question 12

amino acid hormone synthesis

Answer 12

Produced in rough ER and cytosol.
Mainly derived from the amino acid tyrosine.

Question 13

amino acid hormone examples

Answer 13

All hormones produced by the adrenal
medulla (epinephrine and norepinephrine, which
are water-soluble). Also includes charged amino-acid
derivatives T3 and T4 (lipid-soluble).

Question 14

hypothalamus function

Answer 14

coordinates the body’s internal
environment and maintains homeostasis.

Question 15

what is another name for the pituitary gland

Answer 15

hypophysis

Question 16

posterior pituitary

Answer 16

It is a direct neuronal
extension of the hypothalamus.

Question 17

what are the hormones produced by the hypothalamus

Answer 17

● Antidiuretic hormone (ADH aka vasopressin):
Decreases urination by increasing water retention.
Targets nephrons, increasing the number of
aquaporins for water reuptake.
● Oxytocin: Causes uterine contractions during
child labor and the release of milk during
breastfeeding (mammary gland). Oxytocin also
plays an important role in facilitating maternal
behavior (drive to be a good parent).

Question 18

anterior pituitary

Answer 18

Produces its own hormones. It
is connected to the hypothalamus through a
hypophyseal portal system, which allows for
quick diffusion of hormones through a portal
vein.

Question 19

hypothalamic releasing hormones

Answer 19

● GnRH (gonadotropin-releasing hormone):
Causes release of luteinizing hormone (LH) and
follicle stimulating hormone (FSH).
● TRH (thyrotropin-releasing hormone): Causes
release of thyroid stimulating hormone (TSH).
● CRH (corticotropin-releasing hormone):
Causes release of adrenocorticotropic hormone
(ACTH).
● GRH (growth hormone-releasing hormone):
Causes release of growth hormone (GH).

Question 20

anterior pituiatry hormones

Answer 20

The anterior pituitary then produces its own
hormones, classified as tropic hormones and direct
hormones.

tropic hormones:
target other endocrine glands for
further hormone release.

direct hormones:
target organs directly for effects.

Question 21

anterior pituitary direct homrones

Answer 21

Prolactin
growth hormone

Question 22

anterior pituitary tropic hormones

Answer 22

FSH
LH
ACTH
TSH

Question 23

FSH

Answer 23

Follicle
growth (females) and sperm maturation (males) in the gonads.

Stimulates follicle growth in ovaries, which
results in the increased production of
progesterone and estrogen.

Stimulates sperm maturation.

Question 24

LH

Answer 24

Stimulates ovulation,
corpus luteum formation (females), and
testosterone production (males) in the gonads.

During menstrual cycle, the LH surge causes
ovulation. This results in the formation of a
corpus luteum, which produces progesterone
and estrogen.

Triggers testosterone production by Leydig
cells.

Question 25

ACTH

Answer 25

Stimulates release of glucocorticoids from the adrenal gland to fight stress. This also leads to an increase in glucose levels in the body.

Question 26

TSH

Answer 26

Stimulates T3 and T4 production by the thyroid gland to increase metabolism.

Question 27

prolactin

Answer 27

Stimulates mammary gland development and increases milk production after childbirth.

Question 28

growth hormone

Answer 28

Stimulates body cells to grow and divide.

Question 29

thyroid gland

Answer 29

largest endocrine organ and is located in front of the trachea. has three hormones

Question 30

T3

Answer 30

Triiodothyronine a hormone of the thyroid gland Released in response to TSH and increases metabolism in the body. Has a negative feedback effect on TSH secretion.

Question 31

T4

Answer 31

Thyroxine (T4): Performs the same actions as T3 above. However, T4 has one more iodine and gets converted into T3 upon cell uptake. It is much less potent than T3 but is more stable in the blood.

Question 32

calcitonin

Answer 32

Secreted by parafollicular thyroid cells (C cells) to decrease blood calcium levels.

Question 33

hypothyroidism

Answer 33

describes the under-secretion of T3 and T4, resulting in reduced levels of metabolism in the body.

Question 34

hyperthyroidism

Answer 34

describes the over-secretion of T3 and T4, resulting in increased levels of metabolism in the body.

Question 35

what does hypo and hyperthyroidism lead to

Answer 35

Both hypothyroidism and hyperthyroidism can lead to goiter (physical enlargement of the thyroid gland). Hypothyroidism causes over-secretion of TRH to compensate for low T3 and T4, enlarging the thyroid gland, while hyperthyroidism itself results from a hyperactive thyroid gland. A goiter is the irregular growth of the thyroid gland. Iodine deficiency is the most common cause of a goiter.

Question 36

parathyroid gland and PTH

Answer 36

The parathyroid gland secretes parathyroid hormone (PTH), which increases blood calcium levels.

Question 37

pancreas

Answer 37

The pancreas is a gland that contains exocrine and endocrine tissue. endocrine: secretes digestive enzymes through the pancreatic duct to the small intestine.

Question 38

endocrine tissue of the pancreas

Answer 38

The endocrine tissue (the islets of Langerhans) secretes glucagon and insulin. These two hormones are each secreted by a different cell type as listed below:

Question 39

alpha cells

Answer 39

Secrete glucagon in response to low blood glucose levels. Glucagon raises glucose levels by stimulating the liver and fat tissue to release their glucose storages.

Question 40

beta cells

Answer 40

Secrete insulin in response to high blood glucose levels. Insulin lowers glucose levels by stimulating the liver, muscle, and fat tissue to store glucose.

Question 41

insulin

Answer 41

is a peptide hormone that triggers an increase in the number of glucose transporters embedded within the cell membrane. This increases the facilitated diffusion of glucose from the bloodstream into cells and reduces blood glucose levels.

Question 42

adrenal glands

Answer 42

Our body has two adrenal glands. Each adrenal gland has an outer cortex and an inner medulla. They mainly help the body deal with stress.

Question 43

adrenal cortex functions

Answer 43

● Deals with longer term stress. ● Stimulated by secretion of ACTH from the anterior pituitary. ● Releases steroid hormones. ● Produces glucocorticoids (i.e., cortisol) to raise blood glucose levels for immediate fuel during periods of long-term stress. However, this also lowers our immune response. ● Produces mineralocorticoids (i.e., aldosterone) to increase blood volume and blood pressure by raising reabsorption of Na+ . Water passively gets reabsorbed with Na+ due to osmosis. ● Produces a small amount of male sex hormones (androgens).

Question 44

adrenal medulla

Answer 44

● Deals with short-term stress. ● Stimulated by the sympathetic nervous system. ● Releases amino-acid derived hormones. ● Produces catecholamines (epinephrine and norepinephrine) to initiate “fight or flight” response by increasing heart rate and the breakdown of glycogen into glucose. Epinephrine can cause vasoconstriction or vasodilation.

Question 45

LH and FSH

Answer 45

After stimulation by LH and FSH, the ovaries produce progesterone and estrogen, while the testes produce androgens such as testosterone.