NR-507 Endocrine System
Practice Test
(2026-2027)
** 100% Guaranteed Pass
** Expert-Verified Explanation
** Questions with Verified Answer
** Latest Edition | Updated
, The anterior lobe of the pituitary produces its own True
hormones.
True
False
The only way for a hormone to reach a target cell is The endocrine cell can also secrete hormones that target cells directly close it.
through the blood stream. When this occurs, this type of secretion is known as paracrine signaling.
True
False
Lipid-derived hormones cross the cell membrane and This statement is true. Lipid-derived hormones cross the cell membrane and bind
bind to receptors in the cell's cytoplasm. to receptors in the cell's cytoplasm.
True
False
To be considered a lipid hormone, it must be bound to a It must be bound to a protein and it bind to receptors on the cell membrane
protein and it must bind to receptors inside the cell rather than inside the cell membrane.
membrane.
True
False
The pineal gland is responsible for regulating the sleep- True
wake cycle.
True
False
Endocrine System-Overview The purpose of the endocrine system is to maintain the body's homeostasis
using hormones. Hormones are signaling molecules.
When an endocrine cell receives a stimulus or command, this stimulates the
endocrine cell to secrete hormones into the blood stream. The hormones will
then target and bind onto a specific receptor on a target cell. This will cause the
target cell to initiate a response.
Endocrine System Characteristics Hormones have specific rates and rhythms of secretion.
Hormones operate within feedback systems, either positive or negative, to
maintain an optimal internal environment.
Hormones affect only cells with specific receptors and then act on those cells to
initiate specific cell functions or activities.
Secretion Patterns (1) circadian or diurnal patterns, (2) pulsatile and cyclic patterns, and (3) patterns
that depend on levels of circulating substrates (e.g., calcium, sodium, potassium,
or the hormones themselves).
Three types of signaling hormones Steroid, peptide, and amine
Steroid Lipids derived from cholesterol
Lipophilic - can cross membrane- need protein for transfer
Undergoes constitutive secretion
Testosterone
Estrogen / Progesterone
Can remain in the blood for hours to days
Peptide Short polypeptide chains
Hydrophilic - cannot cross membrane/Does not require a protein to circulate
Undergoes regulatory secretion
Insulin
Glucagon
Short half life
Amine Derived from aromatic amino acid
Hydrophilic - cannot cross membrane
Undergoes regulatory secretion
Thyroxine
Short half life
How can a hormone initiate a response? Only free circulating hormones can initiate responses inside of a target cell
Upon arrival to the cell membrane, the protein-bound hormone must disengage
from the protein in order to diffuse into the cell where its effects can be exerted.
Practice Test
(2026-2027)
** 100% Guaranteed Pass
** Expert-Verified Explanation
** Questions with Verified Answer
** Latest Edition | Updated
, The anterior lobe of the pituitary produces its own True
hormones.
True
False
The only way for a hormone to reach a target cell is The endocrine cell can also secrete hormones that target cells directly close it.
through the blood stream. When this occurs, this type of secretion is known as paracrine signaling.
True
False
Lipid-derived hormones cross the cell membrane and This statement is true. Lipid-derived hormones cross the cell membrane and bind
bind to receptors in the cell's cytoplasm. to receptors in the cell's cytoplasm.
True
False
To be considered a lipid hormone, it must be bound to a It must be bound to a protein and it bind to receptors on the cell membrane
protein and it must bind to receptors inside the cell rather than inside the cell membrane.
membrane.
True
False
The pineal gland is responsible for regulating the sleep- True
wake cycle.
True
False
Endocrine System-Overview The purpose of the endocrine system is to maintain the body's homeostasis
using hormones. Hormones are signaling molecules.
When an endocrine cell receives a stimulus or command, this stimulates the
endocrine cell to secrete hormones into the blood stream. The hormones will
then target and bind onto a specific receptor on a target cell. This will cause the
target cell to initiate a response.
Endocrine System Characteristics Hormones have specific rates and rhythms of secretion.
Hormones operate within feedback systems, either positive or negative, to
maintain an optimal internal environment.
Hormones affect only cells with specific receptors and then act on those cells to
initiate specific cell functions or activities.
Secretion Patterns (1) circadian or diurnal patterns, (2) pulsatile and cyclic patterns, and (3) patterns
that depend on levels of circulating substrates (e.g., calcium, sodium, potassium,
or the hormones themselves).
Three types of signaling hormones Steroid, peptide, and amine
Steroid Lipids derived from cholesterol
Lipophilic - can cross membrane- need protein for transfer
Undergoes constitutive secretion
Testosterone
Estrogen / Progesterone
Can remain in the blood for hours to days
Peptide Short polypeptide chains
Hydrophilic - cannot cross membrane/Does not require a protein to circulate
Undergoes regulatory secretion
Insulin
Glucagon
Short half life
Amine Derived from aromatic amino acid
Hydrophilic - cannot cross membrane
Undergoes regulatory secretion
Thyroxine
Short half life
How can a hormone initiate a response? Only free circulating hormones can initiate responses inside of a target cell
Upon arrival to the cell membrane, the protein-bound hormone must disengage
from the protein in order to diffuse into the cell where its effects can be exerted.
