Chapters 17 & 18 Flashcards
True or False: The principal method the body uses to coordinate cellular activity and maintain homeostasis is through the secretion of chemical messengers.
True
Chemical messengers play an important role in regulating body cavities by allowing _____________ between cells.
communication
The controlled release of chemicals from a cell, such as the release of hormones from an endocrine gland is called _________.
secretion
The endocrine system may be defined as:
the glands, tissues, and cells that secrete hormones
A ductless hormone that secretes hormones into blood describes a(n) ________ gland.
endocrine
A _______ is a chemical messenger that is secreted into the body by an endocrine gland or isolated gland cell and triggers a physiological response in distant target cells.
hormone
What type of glands secrete their products onto a body surface or into a hollow organ via ducts?
exocrine glands
Which brain structure is included in both the nervous and the endocrine system?
hypothalamus
What is the overall purpose of chemical messengers in the body?
communication between cells
Depending on its mechanism of secretion and action, epinephrine can be which of the following? electrical signal hormone neurotransmitter target
hormone, neurotransmitter
Place the events of lipid soluble hormone binding with a nuclear receptor in chronological order.
- lipid soluble hormone diffuses through the plasma membrane
- lipid soluble hormone binds to intracellular receptor
- hormone receptor complex binds to a hormone response element of DNA
- synthesis of specific mRNA
- mRNA binds to ribosomes
- production of a new protein
The interaction of a hormone with a _______ receptor results in protein synthesis.
nuclear
Ture or False: The specific sequences of DNA that nuclear receptors bind to are called transcription factor elements.
False
The combination of a hormone and its nuclear receptor forms a transcription factor because it activates the formation of _____.
mRNA
Membrane-bound receptors directly activate cell responses by:
altering the activity of intracellular enzymes
changing the activity of G proteins
The specific sequence of DNA that is recognized and bound to by a hormone-nuclear receptor complex is called the _______ _________ _________.h
hormone response element
The combination of a hormone and its nuclear receptor forms a transcription factor because it activates the formation of _____.
mRNA
True or False: A chemical produced in a cell in response to the binding of chemical messenger to a membrane receptor is referred to as a(n) first messenger.
False
A coordinated set of events in which an intracellular mediator activates specific cellular processes in response to a hormone is called a ______ - ________ system.
second-messenger
cAMP functions in a cell is a(n) _________ - __________.
second-messenger
Which chemical class of hormones uses second messenger system?
water-soluble
A protein complex of three protein sub-units found on the inner surface of the plasma membrane that can be activated once a chemical messenger binds to a receptor is a __ protein.
G
True or False: The enzyme that converts ATP to cAMP is a G protein.
False
The attachment of phosphate to regulate the activity of an enzyme is referred to as ____________.
Phosphorylation
True or False: Enzymes that regulate the action of other enzymes by attaching phosphates to them are called protein kinases.
True
What enzyme catalyzes the breakdown of cAMP?
Phosphodiesterase
Cyclic AMP in the liver stimulates enzymes that convert ________ to _________.
glycogen
glucose
Know the events of the PIP2 second messenger system in the correct sequence.
- epinephrine binds to a receptor
- G protein is activated
- G protein subunit binds with phospholipase C
- PIP2 is split into IP3 and DAG
- IP3 releases Ca+2 from endoplasmic reticulum
Identify the potential responses when subunits of a G-protein bind to ion channels.
Closing of ion channels
Opening of ion channels
Cyclis GMP is activated by:
a hormone binding to membrane-bound receptor
Which intracellular mediator has an influence on the kidneys causing them to increase sodium and water excretion?
cGMP
The enzyme that converts GTP to cMPG is ________ _________.
guanylate cyclase
Some membrane-bound receptors act as a(n) _______ enzyme and phosphoylate intracellular proteins.
kinase
The binding of the hormone insulin results in phosphorylation of the receptor itselft and other intracellular proteins along with subsequent entry of ________ into cells.
glucose
True of False: Some receptors when bound to their hormone directly influence the activity of intracellular enzymes.
True
One hormone molecule can stimulate the synthesis of hundreds of other enzymes molecules. This is known as:
enzyme amplification
The action o ________-_________ receptors in immediate responses, while ________ receptor actions are more long-term.
membrane-bound
nuclear
Lipid-soluble hormones are __________ in nature, therefore, they can easily cross the target cell membrane to bind to intracellular receptors.
hydrophobic
Identify the hormones that use membrane-bound receptors:
ADH Parathyroid hormone (PTH) Growth hormone (GH) insulin FSH
Which of the following hormones use nuclear receptors?
thyroid hormone
estrogen
cortisol
testosterone
In order for a hormone to act on a target cell, if must bind to a specific protein ________.
receptor
The part of the target cell to which a hormone binds is called a(n) _________ site.
receptor
A hormone receptor can be described as:
a specific protein or glycoprotein embedded in the plasma membrane
Since hormone receptors have a very high affinity for binding hormones, this means a _______ concentration of is needed to activate enough receptors.
small
The lowered sensitivity to reproductive hormones after long periods of exposure is due to ______-________ of the receptors.
down-regulator
The process in which a cell reduces its receptors population and thus becomes less sensative to a hormone is called ______-__________.
down-regulation
The specific sequence of DNA that is recognized and bound to by a hormone-nuclear receptor complex is called the ________ _________ __________.
hormone response element
Which chemical class of hormones uses second messenger systems?
water soluble
The activation of a G protein that results in a breaking of phosphoinositol disphosphate (PIP2) into two intracellular mediators is an example of a ________ __________ systems.
second messenger
The synthesis of what intracellular mediator is directly activated by hormone-receptor interaction?
cGMP
The binding of the hormone insulin results in phosphorylation of the receptor itself and other intracellular proteins along with subsequent entry of ________ into cells.
glucose
_________-soluble hormones are hydrophilic, making it difficult for them to cross the membrane at the target cell to interact with receptors.
water
Insulin is a hormone that utilizes __________-_______ receptors.
membrane-bound
Downregulation is the:
reduction in receptor population and decreased sensitivity to a hormone
The increase in LH receptors in the ovary during menstrual cycles is an example of __-_________.
up-regulation
_______-soluble hormones are able to utilize nuclear receptors.
lipid
Which type of receptors are intracellular?
nuclear
Place the events of a lipid soluble hormone binding with a nuclear receptor in chronological order:
- Lipid-soluble hormone diffuses through the plasma membrane
- Lipid-soluble hormone binds to intracellular receptor
- Hormone-receptor complex binds to a hormone response element of DNA
- Synthesis of specific mRNA
- mRNA binds to ribosomes
- Production of a new protein
When an activated G protein interacts with adenylate cyclase, what is produced?
cAMP
Place the following second-messenger system actions in the order they occur.
- hormone receptor binding activities G-protein
- G protein activates adenylate cyclase
- adenylate cyclase produces cAMP
- cAMP activates protein kinases
Chemical messengers that stimulate the same cell that secreted them are called ___________.
autocrines
What are chemical messengers that diffuse through tissue fluid and affect only nearby cells called?
paracrines
What class of chemical messengers is secreted into the blood to activate cells distant from the source cell?
Endocrine Hormone
What type of chemical messengers have local actions?
paracrines, neurotransmitters, autocrines
Which cells influence the activity of the same cells from which they were secreted?
autocrine
A cell acted upon by a nerve fiber, hormone, or other chemical messenger is called a(n) _______.
target
Salivary glands and sweat glands are both types of __________ glands.
exocrine
___________ glands secrete their products into ducts and the surface of the body, whereas _________ glands secrete their products into the blood.
exocrine
endocrine
The study of the glands, tissues, and cells that secrete hormones and of the diagnosis and treatment of their disorders is called _____________.
endocrinology
Which system uses chemical released into the blood as a means of communication?
endocrine
The hormonal regulation of pituitary secretions is a(n) _________ function of the hypothalamus.
endocrine
Neurotransmitters are chemicals released by ________.
neurons
When a neuron releases a chemical messenger into the blood, this messenger is referred to as a: ______________.
neurohormone
Which signaling systems has the longest lived effects?
endocrine
When stimulated, which system responds more quickly?
nervous
Hormones are examples of ________-modulated signals.
amplitude
Hormone secretion can be described as a amplitude-modulated signal. This means that the strength of the signal and the magnitude of the response is determined by the ___________ of the hormone.
concentration
Action potentials are examples of _________-modulated signals.
frequency
Signal that do not vary in size but change in how often they occur are referred to as ___________-modulated signals.
frequency
Lipid-soluble hormones are __________ in nature, therefore, they can easily cross the target cell membrane to bind to intracellular receptors.
hydrophobic
Receptor found either in the nucleus or interacting with the nucleus when activated are called ________ receptors.
nuclear
The first step in a second messenger system is:
the hormone diffusing through the plasma
Secreted into interstitial fluid; influences the same cell that secreted it:
autocrine
Secreted into interstitial fluid; influences cells in close proximity to the secreting cell:
paracrine
Produced by neurons; influences post-synaptic cells:
neurotransmitter
Secreted into the bloodstream and carried ti target cells, which may by far away from secreting cell:
hormone
What of the following are endocrine functions of the hypothalamus?
control of pituitary secretions
production and secretion of hormones
When a neuron releases a chemical messenger into the blood, this messenger is referred to as a:
neurohormone
True or False: In different tissues, a given hormone can use different second messengers.
True
The two mechanisms used to maintain homeostatic levels of hormones in the blood are _______ and ________ feedback, with the first mechanism being more common. (Note: the order in which you put your answers is important; read the question carefully.)
negative
positive
________-soluble hormones are polar molecules.
water
Nuclear receptors can be found in which of the following locations?
nucleus
cytoplasm
The blood levels of MOST hormones is regulated by _______ feedback systems.
negative
Sympathetic neurons can serve as ________ stimuli for hormone release from certain endocrine organs.
neural
The secretion of epinephrine from the adrenal medulla is an example of hormone release due to ________ stimuli.
neural
Hormone that are released from the pituitary gland and cause the release of hormones from a target endocrine organ/tissue are called ________ hormones.
tropic
Releasing hormones from the hypothalamus act as __________ stimuli on the anterior pituitary gland.
hormonal
Hypothalamic topic hormones are described as ___________ hormones if they stimulate pituitary cells to secrete hormones of their own.
releasing
Which of the following is an example of a tropic hormone?
TSH causing release of thyroid hormones from thyroid gland
The three types of stimuli that can inhibit hormonal release are _______, ________, and _________ stimuli.
humoral, neural, & hormonal
A companion hormone’s effect will usually: _____ ______ ________ ___ the action of its secreted hormone.
oppose the effect of
An inhibitory neurotransmitters will _______ hormonal release from its target.
decrease
Hormones from the hypothalamus that decrease secretion from the anterior pituitary are called _________ hormones.
inhibiting
Thyroid hormones controlling its own levels by affecting its pituitary tropic hormone is an example of inhibition by _________ stimuli.
hormonal
Which of the following is NOT a type of stimuli that regulates hormone release?
Renal
True or False: Blood chemistry changes are examples of humoral stimuli, whereas the use of hormones to stimulate the release of other hormones is an example of a hormonal stimulus for hormone release.
true
Blood levels of glucose, amino acids, and other important molecules serve as ________ stimuli for hormone release.
humoral
Glucose and calcium are molecules that may act as _______ stimuli.
humoral
Hyperventilation changes blood pH which would elicit a hormone response by this _______ stimulus.
humoral
Innervation of endocrine glands allows for _______ stimuli to increase hormonal release from that gland.
neural
The secretion of epinephrine from the adrenal medulla is an example of hormone release due to _________ stimuli.
neural
The hypothalamic hormone(s) that stimulate the pituitary to secrete its own hormones is/are _________ __________.
releasing hormones
TSH is released from the anterior pituitary and acts on the thyroid gland, causing it to release thyroid hormones. This pattern of action makes TSH a(n) _______ hormone.
tropic
True or False: The same humoral stimulus can inhibit one hormone but stimulate the release its target.
True
An inhibitory neurotransmitter will _______ hormonal release from its target.
inhibit
After consuming a large carbohydrate rich meal insulin is released by the pancreas to lower serum glucose levels. When serum glucose levels have returned to normal secretion of insulin is inhibited. This is an example of:
negative feedback inhibition
The inhibition of tropic hormone by its target organ hormone is an example of ___________ feedback.
negative
The stimulation of tropic hormone release by its target hormone is an example of _________ feedback.
positive
True or False: Each chemical messenger in the body fits specifically into one of the four classes.
False
Blood chemistry changes are examples of _______ stimuli, whereas sympathetic nervous system impulses are examples of _______ stimuli for hormone release.
humoral
neural
The hormonal response to an emergency life-death situation is usually modulated by ________ stimuli.
neural
Sympathetic neurons can serve as _________ stimuli for hormone release from certain endocrine organs.
neural
Which of the following is an example of a tropic hormone?
TSH causing release of thyroid hormones from thyroid gland
An inhibitory neurotransmitter will _________ hormonal release from its target.
decrease
The pituitary stimulates another endocrine gland to secrete its hormone, and that hormone feeds back to the pituitary of hypothalamus and inhibits further secretion of the pituitary hormone. This is an example of ________ feedback inhibition.
negative
Positive feedback results when a hormone from a target organ ________ the release of the original tropic hormone.
increases
The time required for 50% of a quantity of hormone to be cleared from the bloodstream is the ____-____.
half-life
In order for hormones to function, they must:
bind with receptors on their targets
be transported by the bloodstream
remain stable while traveling in the bloodstream
What are two chemical categories of endocrine hormones?
water-soluble
lipid-soluble
Hormones that are released in large amounts resulting in dramatic changes in blood concentration exemplify a(n) _____ pattern of secretion.
acute
The regulation of blood glucose levels is controlled by a hormone that exhibits a(n) _____ pattern of secretion.
acute
In general, what chemical class of hormones usually exhibits acute secretion patterns?
water-soluble
Certain hormones are released in large amounts in response to stress: their pattern of secretion is ______.
acute
