Bio 245 Klesath Exam 1 NCSU QUESTIONS AND
ANSWERS ALL CORRECT
3 reflex mechanisms that stimulate hormone secretion - -1.Hormonal Stimulation:
stimulus for release of hormones by the binding of another hormone (eg the TSH from
anterior pituitary binds to thyroid gland to release TH)
2.Humoral Stimulation: release of hormone in response to change of blood nutrient levels
(eg blood glucose levels rise so insulin is released from pancreas, or fall and glucagon is
released)
3.Neural Stimulation: direct stimulation from nervous system to endocrine gland (eg
epinephrine and norepinephrine by adrenal medulla during fight or flight)
Hormonal Stimulation - -Stimulus for release of hormones by the binding of another
hormone (eg the TSH from anterior pituitary binds to thyroid gland to release TH)
Humoral Stimulation - -release of hormone in response to change of blood nutrient
levels (eg blood glucose levels rise so insulin is released from pancreas, or fall and
glucagon is released)
Neural Stimulation - -direct stimulation from nervous system to endocrine gland (eg
epinephrine and norepinephrine by adrenal medulla during fight or flight)
Steroids - -lipid soluble molecules synthesized by cholesterol
1. Gonads (Estrogen, Progesterone, Testosterone)
2. Adrenal Cortex hormones (Corticosteroids like cortisol, mineralocorticoids, aldosterone)
Biogenic Amines - -modified amino acids, water soluble (except thyroid)
1. Catecholamines (epinephrine and norepinephrine)
2. Thyroid Hormone → lipid soluble
3. Melatonin
Proteins - -most hormones, small chains of amino acids, water soluble
1. Small peptides and large polypeptides
2. Glycoproteins
Local Hormones - -DO NOT circulate in blood, so only affect either same cell that
produced them (autocrine) or neighboring cells (Paracrine)
1. Eicosanoids: synthesized through enzymatic cascade, Phospholipase A2 removes fatty
acid from phospholipid within the plasma membrane
, Bio 245 Klesath Exam 1 NCSU QUESTIONS AND
ANSWERS ALL CORRECT
--> prostaglandins
Prostaglandins - --Famous eicosanoid
-are diverse group: synthesized by most tissues in the body
-Stimulate pain receptors, reduce fever, increase inflammatory response
Lipid soluble hormones: - -Can cross membrane, but needs carrier protein while
circulating in blood, once unbound they can enter the nucleus
a. Has a longer half-life bc protected by carrier proteins
b. Once inside the cells, hormone binds to intracellular receptor either in nucleus of
cytosol
c. Once bound, forms a hormone receptor complex which interacts with DNA directly in
regions called Hormone Response Element (HRE)
d. Initiates transcription/translation and production of a new protein
Water soluble hormones - -Travel free in blood so shorter half-life, cannot enter
plasma membrane so binds to a membrane bound receptor
a. Second messengers begin a signal transduction pathway, which can cause an amplified
signal
G protein activation by water-soluble hormones - -a. Hormone binds to G-Protein
and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
Adenylate Cyclase - -a. Hormone binds to G-Protein and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
c. Using ATP, cAMP is created and activates protein kinase A, which will phosphorylate
things
→ small concentration of hormone can have large effect on cell
Phospholipase C - -i. Phospholipase C is enzyme activated by G-protein
ii. Splits into PIP2 and second messengers, DAG and IP3
iii. DAG activates kinase C
ANSWERS ALL CORRECT
3 reflex mechanisms that stimulate hormone secretion - -1.Hormonal Stimulation:
stimulus for release of hormones by the binding of another hormone (eg the TSH from
anterior pituitary binds to thyroid gland to release TH)
2.Humoral Stimulation: release of hormone in response to change of blood nutrient levels
(eg blood glucose levels rise so insulin is released from pancreas, or fall and glucagon is
released)
3.Neural Stimulation: direct stimulation from nervous system to endocrine gland (eg
epinephrine and norepinephrine by adrenal medulla during fight or flight)
Hormonal Stimulation - -Stimulus for release of hormones by the binding of another
hormone (eg the TSH from anterior pituitary binds to thyroid gland to release TH)
Humoral Stimulation - -release of hormone in response to change of blood nutrient
levels (eg blood glucose levels rise so insulin is released from pancreas, or fall and
glucagon is released)
Neural Stimulation - -direct stimulation from nervous system to endocrine gland (eg
epinephrine and norepinephrine by adrenal medulla during fight or flight)
Steroids - -lipid soluble molecules synthesized by cholesterol
1. Gonads (Estrogen, Progesterone, Testosterone)
2. Adrenal Cortex hormones (Corticosteroids like cortisol, mineralocorticoids, aldosterone)
Biogenic Amines - -modified amino acids, water soluble (except thyroid)
1. Catecholamines (epinephrine and norepinephrine)
2. Thyroid Hormone → lipid soluble
3. Melatonin
Proteins - -most hormones, small chains of amino acids, water soluble
1. Small peptides and large polypeptides
2. Glycoproteins
Local Hormones - -DO NOT circulate in blood, so only affect either same cell that
produced them (autocrine) or neighboring cells (Paracrine)
1. Eicosanoids: synthesized through enzymatic cascade, Phospholipase A2 removes fatty
acid from phospholipid within the plasma membrane
, Bio 245 Klesath Exam 1 NCSU QUESTIONS AND
ANSWERS ALL CORRECT
--> prostaglandins
Prostaglandins - --Famous eicosanoid
-are diverse group: synthesized by most tissues in the body
-Stimulate pain receptors, reduce fever, increase inflammatory response
Lipid soluble hormones: - -Can cross membrane, but needs carrier protein while
circulating in blood, once unbound they can enter the nucleus
a. Has a longer half-life bc protected by carrier proteins
b. Once inside the cells, hormone binds to intracellular receptor either in nucleus of
cytosol
c. Once bound, forms a hormone receptor complex which interacts with DNA directly in
regions called Hormone Response Element (HRE)
d. Initiates transcription/translation and production of a new protein
Water soluble hormones - -Travel free in blood so shorter half-life, cannot enter
plasma membrane so binds to a membrane bound receptor
a. Second messengers begin a signal transduction pathway, which can cause an amplified
signal
G protein activation by water-soluble hormones - -a. Hormone binds to G-Protein
and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
Adenylate Cyclase - -a. Hormone binds to G-Protein and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
c. Using ATP, cAMP is created and activates protein kinase A, which will phosphorylate
things
→ small concentration of hormone can have large effect on cell
Phospholipase C - -i. Phospholipase C is enzyme activated by G-protein
ii. Splits into PIP2 and second messengers, DAG and IP3
iii. DAG activates kinase C
