PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
What are the functions of the endocrine system? - (answer)- maintain constant internal environment via
regulation of metabolism and H2O/electrolyte balance
- adaptive stress response
- growth and development
- reproduction
- red blood cell production
- integrating with the ANS in regulating both the circulation and digestive functions
What are hormones? - (answer)hormones are chemical substances that are secreted directly into the
blood at low quantities and exert a physiological effect at a distant target tissue
What are characteristics of hydrophilic hormones? - (answer)- water loving
- highly water soluble and have low lipid solubility
- found unbound to carrier molecules within the plasma
- most are peptides or proteins
- amines are hormones based on single amino acid residues
What are examples of amine hormones? - (answer)- catecholamines (norepinephrine and epinephrine)
- catecholamines are found free and bound to carrier molecules
- thyroid hormones
- thyroid hormones are not hydrophilic
How are peptide hormones synthesized? - (answer)synthesized and secreted by the same cellular
machinery that makes proteins within cells
How are peptide hormones synthesized in the synthesis phase? - (answer)large precursor proteins called
preprohormones are synthesized by ER ribosomes into prohormones
,PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
How are peptide hormones synthesized in the packaging phase? - (answer)as they travel through the ER
and Golgi complex, these prohormones are processed into active hormones and packaged into secretory
vesicles
How are peptide hormones synthesized in the storage phase? - (answer)these hormone containing
secretory vesicles can be stored until the cell receives the appropriate signal
How are peptide hormones synthesized in the secretion phase? - (answer)the appropriate signal
initiates exocytosis if the vesicles and the hormones are released into the blood
What are characteristics of lipophilic hormones? - (answer)- lipid loving
- highly soluble in lipids and poorly soluble in water
- require a carrier molecule for transport throughout the body
What are examples of lipophilic hormones? - (answer)- amine thyroid hormone
- steroid hormones
How are steroid hormones synthesized ? - (answer)- all synthesized from cholesterol
- which steroid hormone is produced by a particular tissue depends on the specific enzymes within the
cells of that tissue
- not stored
- they are secreted as they are synthesized
- to regulate the amount of steroid hormone released, you need to regulate its synthesis
Where is cortisol made? - (answer)adrenal cortex
Which hormones are dissolved in plasma? - (answer)peptide hormones are able to freely dissolve in
plasma
,PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
Which hormones are found bound to carrier molecules or proteins? - (answer)steroid and thyroid
hormones bind to specific carrier molecules or to plasma proteins such as albumin
Which hormones are dissolved in plasma or bound to carrier molecules or proteins? -
(answer)catecholamines are unique as 50% are found free in the plasma and 50% bind to albumin, they
are water soluble
How do hormones interact with their target cells? - (answer)- only free, unbound hormones can interact
with a receptor at its target cell
- not an issue for hydrophilic hormones and catecholamines
What is the dynamic equilibrium of lipophilic hormones binding to its carrier? - (answer)- at a given time,
not 100% of a steroid hormone in the blood is bound to its carrier molecule
- instead, the hormones are dynamically unbinding and rebinding which results in a small fraction of
hormone that is unbound at any given time
- this unbound hormone is active and able to act on target cells
How do lipophilic hormones interact with their target cells? - (answer)dynamic equilibrium
Where are the receptors for hydrophilic hormones? - (answer)- peptide hormones and catecholamines
bind to specific receptors on the outer surface of the plasma of their target cells
- they are unable to freely cross the lipid bilayer of the plasma membrane
Where are the receptors for lipophilic hormones? - (answer)steroid hormones and thyroid hormones
can easily slip through the plasma membrane and bind to specific receptors inside their target cells
What happens after peptide hormones or catecholamines bind to its receptor? - (answer)- binding of
these hormones to their surface receptors produces effects within cells by activating second messenger
systems
- these pathways are able to amplify the initial signal as low concentrations of hormones trigger large
cellular responses
, PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
How does cAMP act as a secondary messenger? - (answer)- an extracellular messenger binds to a
receptor, activating a G protein which shuttles to and activates several adenylyl cyclase molecules
- these activated proteins convert many molecules of ATP to cAMP which then activate protein kinase A
- the activated protein kinase A enzymes then phosphorylate and activate target proteins which can
bring about the desired result
How does calcium act as a secondary messenger? - (answer)- an extracellular messenger binds to a
receptor activating a G protein, which shuttles to activate several phospholipase C enzymes
- these proteins convert PIP2 to IP3 and DAG
- IP3 mobilizes intracellular Ca2+ which activates calmodulin
- the Ca2+-calmodulin complexes then activate Ca2+-calmodulin-dependent protein kinase (CaM
kinase), which phosphorylate and activate target proteins, bringing about the desired response
How to lipophilic hormones exert their effects on cells? - (answer)regulating protein synthesis
Where can lipophilic hormone receptors be found? - (answer)within the cytoplasm or the nucleus
What are the steps that lipophilic hormones regulate protein synthesis? - (answer)- free lipophilic
hormone diffuse across the plasma membrane and/or the nuclear membrane to interact with
intracellular receptors
- the hormone-receptor complex (H-R) binds to the hormone response element (HRE) within the DNA
- DNA binding activates specific genes and produces mRNA
- the mRNA leaves the nucleus
- the mRNA binds to a ribosome and proteins are synthesized
- these newly synthesized proteins ultimately lead to the cellular response of the hormone
What are the key differences between hormones and neurotransmitters? - (answer)- neurotransmitters
belong to the nervous system and hormones belong to the endocrine system
- neurotransmitters are transported across a synaptic cleft, hormones are transported by the blood
- neurotransmitters are produces by neurons, hormones are produced by endocrine glands
What are the functions of the endocrine system? - (answer)- maintain constant internal environment via
regulation of metabolism and H2O/electrolyte balance
- adaptive stress response
- growth and development
- reproduction
- red blood cell production
- integrating with the ANS in regulating both the circulation and digestive functions
What are hormones? - (answer)hormones are chemical substances that are secreted directly into the
blood at low quantities and exert a physiological effect at a distant target tissue
What are characteristics of hydrophilic hormones? - (answer)- water loving
- highly water soluble and have low lipid solubility
- found unbound to carrier molecules within the plasma
- most are peptides or proteins
- amines are hormones based on single amino acid residues
What are examples of amine hormones? - (answer)- catecholamines (norepinephrine and epinephrine)
- catecholamines are found free and bound to carrier molecules
- thyroid hormones
- thyroid hormones are not hydrophilic
How are peptide hormones synthesized? - (answer)synthesized and secreted by the same cellular
machinery that makes proteins within cells
How are peptide hormones synthesized in the synthesis phase? - (answer)large precursor proteins called
preprohormones are synthesized by ER ribosomes into prohormones
,PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
How are peptide hormones synthesized in the packaging phase? - (answer)as they travel through the ER
and Golgi complex, these prohormones are processed into active hormones and packaged into secretory
vesicles
How are peptide hormones synthesized in the storage phase? - (answer)these hormone containing
secretory vesicles can be stored until the cell receives the appropriate signal
How are peptide hormones synthesized in the secretion phase? - (answer)the appropriate signal
initiates exocytosis if the vesicles and the hormones are released into the blood
What are characteristics of lipophilic hormones? - (answer)- lipid loving
- highly soluble in lipids and poorly soluble in water
- require a carrier molecule for transport throughout the body
What are examples of lipophilic hormones? - (answer)- amine thyroid hormone
- steroid hormones
How are steroid hormones synthesized ? - (answer)- all synthesized from cholesterol
- which steroid hormone is produced by a particular tissue depends on the specific enzymes within the
cells of that tissue
- not stored
- they are secreted as they are synthesized
- to regulate the amount of steroid hormone released, you need to regulate its synthesis
Where is cortisol made? - (answer)adrenal cortex
Which hormones are dissolved in plasma? - (answer)peptide hormones are able to freely dissolve in
plasma
,PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
Which hormones are found bound to carrier molecules or proteins? - (answer)steroid and thyroid
hormones bind to specific carrier molecules or to plasma proteins such as albumin
Which hormones are dissolved in plasma or bound to carrier molecules or proteins? -
(answer)catecholamines are unique as 50% are found free in the plasma and 50% bind to albumin, they
are water soluble
How do hormones interact with their target cells? - (answer)- only free, unbound hormones can interact
with a receptor at its target cell
- not an issue for hydrophilic hormones and catecholamines
What is the dynamic equilibrium of lipophilic hormones binding to its carrier? - (answer)- at a given time,
not 100% of a steroid hormone in the blood is bound to its carrier molecule
- instead, the hormones are dynamically unbinding and rebinding which results in a small fraction of
hormone that is unbound at any given time
- this unbound hormone is active and able to act on target cells
How do lipophilic hormones interact with their target cells? - (answer)dynamic equilibrium
Where are the receptors for hydrophilic hormones? - (answer)- peptide hormones and catecholamines
bind to specific receptors on the outer surface of the plasma of their target cells
- they are unable to freely cross the lipid bilayer of the plasma membrane
Where are the receptors for lipophilic hormones? - (answer)steroid hormones and thyroid hormones
can easily slip through the plasma membrane and bind to specific receptors inside their target cells
What happens after peptide hormones or catecholamines bind to its receptor? - (answer)- binding of
these hormones to their surface receptors produces effects within cells by activating second messenger
systems
- these pathways are able to amplify the initial signal as low concentrations of hormones trigger large
cellular responses
, PHGY 216 Module 1 Exam – Complete Study Guide With Practice Questions & Detailed Answers
How does cAMP act as a secondary messenger? - (answer)- an extracellular messenger binds to a
receptor, activating a G protein which shuttles to and activates several adenylyl cyclase molecules
- these activated proteins convert many molecules of ATP to cAMP which then activate protein kinase A
- the activated protein kinase A enzymes then phosphorylate and activate target proteins which can
bring about the desired result
How does calcium act as a secondary messenger? - (answer)- an extracellular messenger binds to a
receptor activating a G protein, which shuttles to activate several phospholipase C enzymes
- these proteins convert PIP2 to IP3 and DAG
- IP3 mobilizes intracellular Ca2+ which activates calmodulin
- the Ca2+-calmodulin complexes then activate Ca2+-calmodulin-dependent protein kinase (CaM
kinase), which phosphorylate and activate target proteins, bringing about the desired response
How to lipophilic hormones exert their effects on cells? - (answer)regulating protein synthesis
Where can lipophilic hormone receptors be found? - (answer)within the cytoplasm or the nucleus
What are the steps that lipophilic hormones regulate protein synthesis? - (answer)- free lipophilic
hormone diffuse across the plasma membrane and/or the nuclear membrane to interact with
intracellular receptors
- the hormone-receptor complex (H-R) binds to the hormone response element (HRE) within the DNA
- DNA binding activates specific genes and produces mRNA
- the mRNA leaves the nucleus
- the mRNA binds to a ribosome and proteins are synthesized
- these newly synthesized proteins ultimately lead to the cellular response of the hormone
What are the key differences between hormones and neurotransmitters? - (answer)- neurotransmitters
belong to the nervous system and hormones belong to the endocrine system
- neurotransmitters are transported across a synaptic cleft, hormones are transported by the blood
- neurotransmitters are produces by neurons, hormones are produced by endocrine glands
