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

Neurons – secrete neurohormones that circulate in the blood

Answer 3

E.g.1: neurons in the hypothalamus secrete several different
“releasing hormones”, like Growth Hormone Releasing Hormone
(GHRH) that act on the anterior pituitary gland.

Question 4

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

Answer 4

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

Question 5

Properties of hormones: Different tissues can secrete the same hormone

Answer 5

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

Question 6

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

Answer 6

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 7

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

Answer 7

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

Question 8

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

Answer 8

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 9

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

Answer 9

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

Question 10

Hormones control

Answer 10

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 11

Hormones function by controlling the

Answer 11

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