Textbook Question
Decreased blood calcium level would result in increased:
(a) Secretion of calcitonin
(b) Secretion of PTH
(c) Elimination of calcium by the kidneys
(d) Osteoclast activity
(e) Excitability of neural membranes
1
views
Ch. 18 The Endocrine System
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 An Introduction to Anatomy and Physiology25
- Ch. 2 The Chemical Level of Organization34
- Ch. 3 The Cellular Level of Organization29
- Ch. 4 The Tissue Level of Organization24
- Ch. 5 The Integumentary System17
- Ch. 6 Bones and Bone Structure33
- Ch. 7 The Axial Skeleton11
- Ch. 8 The Appendicular Skeleton17
- Ch. 9 Joints13
- Ch. 10 Muscle Tissue12
- Ch. 11 The Muscular System28
- Ch. 12 Nervous Tissue18
- Ch. 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes22
- Ch. 14 The Brain and Cranial Nerves20
- Ch. 15 Sensory Pathways and the Somatic Nervous System17
- Ch. 16 The Autonomic Nervous System and Higher-Order Functions30
- Ch. 17 The Special Senses15
- Ch. 18 The Endocrine System21
- Ch. 19 Blood31
- Ch. 20 The Heart31
- Ch. 21 Blood Vessels and Circulation26
- Ch. 22 The Lymphatic System and Immunity25
- Ch. 23 The Respiratory System4
- Ch. 24 The Digestive System18
- Ch. 26 The Urinary System31
- Ch. 27 Fluids & Electrolytes30
- Ch. 28 The Reproductive System12
- Ch. 29 Development and Inheritance17
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook
Chapter 18, Problem 22
A researcher observes that stimulation by a particular hormone induces a marked increase in the activity of G proteins in the target plasma membrane. The hormone being studied is probably:
(a) A steroid
(b) A peptide
(c) Testosterone
(d) Estrogen
(e) Aldosterone
Verified step by step guidance1
Step 1: Understand the role of G proteins in cell signaling. G proteins are intracellular proteins that act as molecular switches inside cells, and they are typically activated by cell surface receptors known as G protein-coupled receptors (GPCRs). These receptors respond to extracellular signals like hormones by activating G proteins.
Step 2: Identify which types of hormones commonly use G protein-coupled receptors for their signaling. Peptide hormones often bind to GPCRs on the plasma membrane, leading to activation of G proteins and subsequent intracellular signaling cascades.
Step 3: Recognize that steroid hormones (such as testosterone, estrogen, and aldosterone) generally do not activate G proteins directly. Instead, they typically diffuse through the plasma membrane and bind to intracellular receptors that act as transcription factors to regulate gene expression.
Step 4: Compare the hormone options given: (a) steroid hormones (testosterone, estrogen, aldosterone) versus (b) peptide hormones. Since the question states that the hormone induces increased G protein activity at the plasma membrane, the hormone is more likely to be a peptide hormone.
Step 5: Conclude that the hormone stimulating G protein activity is probably a peptide hormone, as peptide hormones commonly use GPCRs and G proteins for signal transduction.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
G Protein-Coupled Receptors (GPCRs)
GPCRs are membrane receptors that activate G proteins upon binding to specific ligands like hormones. This activation triggers intracellular signaling cascades. Hormones that act through GPCRs typically include peptides and some amines, leading to rapid cellular responses.
Recommended video:
Guided course
9:36
G Protein-Coupled Receptors
Steroid Hormone Signaling
Steroid hormones, such as testosterone, estrogen, and aldosterone, usually pass through the plasma membrane and bind to intracellular receptors. Their signaling does not typically involve G proteins but rather direct regulation of gene transcription in the nucleus.
Recommended video:
Guided course
5:13Actions of Steroid Hormones
Hormone Types and Their Mechanisms
Hormones are classified by their chemical nature: peptides (water-soluble) often bind to surface receptors activating G proteins, while steroids (lipid-soluble) enter cells to modulate gene expression. Understanding these differences helps identify which hormone likely activates G proteins.
Recommended video:
Guided course
13:06Review of Major Hormones
Related Practice
Textbook Question
In what ways can a hormone modify the activities of its target cells?
1
views
Textbook Question
What is the primary difference in the way the nervous and endocrine systems communicate with their target cells?
5
views
Textbook Question
How would blocking the activity of phosphodiesterase (PDE) affect a cell that responds to hormonal stimulation by the cAMP second messenger system?
2
views
Textbook Question
In Type 2 diabetes, insulin levels are frequently normal, yet the target cells are less sensitive to the effects of insulin. This suggests that the target cells:
(a) Are impermeable to insulin
(b) May lack enough insulin receptors
(c) Cannot convert insulin to an active form
(d) Have adequate internal supplies of glucose
(e) Both b and c
6
views
Textbook Question
Roger has been extremely thirsty. He drinks numerous glasses of water every day and urinates a great deal. Name two disorders that could produce these signs and symptoms. What test could a clinician perform to determine which disorder Roger has?
9
views