unit 10: endocrine system

Question 1

endocrine glands

Answer 1

ductless
function= synthesize and secrete hormones

ex: pituitary gland secretes growth hormone

Question 2

isolated endocrine cells in other tissue/organs

Answer 2

ex: the Leydig cells in the testes secrete testosterone

Question 3

Properties of hormones: More than one hormone can be produced in a single endocrine gland

Answer 3

E.g.1: the pituitary gland synthesizes and secretes 6 different
hormones.

Question 4

Properties of hormones: Different tissues can secrete the same hormone

Answer 4

E.g.1: The hypothalamus and the pancreas secrete somatostatin (an inhibitory hormone)

Question 5

Properties of hormones: A single hormone can act on multiple different target cells in
different organs

Answer 5

E.g.1: epinephrine and norepinephrine released by the
adrenal gland can act on cells in the heart, blood vessels,
airways of the respiratory tract, etc

Question 6

Properties of hormones: Multiple hormones can bind to receptors and produce responses
in a single target cell.

Answer 6

norepinephrine, epinephrine, angiotensin, and vasopressin
can all act on the smooth muscle cells of blood vessels to regulate
blood flow and blood pressure

Question 7

Properties of hormones: Hormone secretion can vary over time and can be affected by
changes in the environment

Answer 7

E.g.1: Circadian rhythms involved in release of cortisol and
melatonin. Cortisol secretion from adrenal gland peaks in the early
morning and decreases at night

Question 8

Properties of hormones: Hormones have a half life =length of time required to reduce
hormone concentration in the blood by half

Answer 8

a) Single amino acid derived hormones = minutes
b) Peptide and protein hormones = minutes to hours
c) Steroid hormones = hours

Question 9

Hormones control

Answer 9

Metabolism
Ø Reproduction
Ø Growth and development
Ø Water and electrolyte balance
Ø Digestion and absorption of nutrients
Ø Blood cell production and development
Ø Etc.
Ø i.e. hormones regulate homeostasis.

Question 10

Hormones function by controlling the

Answer 10

1. rates of enzymatic reactions in cells
2. transport of ions or molecules across cell membranes
3. gene expression and protein synthesis.

Question 11

peptide hormones created from

Answer 11

large, inactive precursor proteins called preprohormones

Question 12

types of postranlational modification of preprohormones

Answer 12

phosphorylation- adding phosphate
peptide cleavage (proteolysis)- cutting up preprohormones into component parts

Question 13

steroid hormones (can it cross?)

Answer 13

yes- made on demand(not stored in vesicles like peptide and catecholamine)

Question 14

humoral stimulus

Answer 14

a change in the concentration of non-hormone chemicals in the blood that causes the release or inhibition of a hormone

ex Pancreatic 𝛽cells (in the Islets of
Langerhans) detect blood glucose
levels and release insulin which
ultimately decreases blood glucose

Question 15

Neural Stimulus

Answer 15

endocrine gland may
be stimulated by an autonomic
postganglionic neuron

Question 16

Hormonal Stimulus

Answer 16

When a hormone released from one
gland triggers the release of a
hormone from another gland

Question 17

up vs down regulation of hormone receptors

Answer 17

up: A stimulus increases the synthesis of receptors for
a hormone thus increasing the sensitivity of the target cell to that hormone. Can be triggered by
abnormally or chronically low hormone levels, in
which case the target cell attempts to enhance its responsiveness to the low levels of hormone

down= opposite

Question 18

hypothalamus

Answer 18

collection of nuclei
controls 2 h’s (homeostasis and hormones)

the hypothalamus controls hormone release by controlling pituitary gland

Question 19

trophic hormones

Answer 19

stimulate the production/release of hormones from the anterior pituitary gland

Question 20

anterior pituitary gland

Answer 20

release hormones that cause big effects in body (growth hormones, thyroid stimulating hormones, etc)

Question 21

posterior pituitary gland

Answer 21

secretes 2 hormones but dont synthesize them (syn by hypothalamus)

(oxytocin, vasopressin)