Podcast
Questions and Answers
What is the primary function of glucagon in relation to blood glucose levels?
What is the primary function of glucagon in relation to blood glucose levels?
What stimulates the secretion of glucagon?
What stimulates the secretion of glucagon?
Which of the following statements regarding insulin action is correct?
Which of the following statements regarding insulin action is correct?
What is one effect of glucagon on lipid metabolism?
What is one effect of glucagon on lipid metabolism?
Signup and view all the answers
Which of the following hormones is considered a counterregulatory hormone to insulin?
Which of the following hormones is considered a counterregulatory hormone to insulin?
Signup and view all the answers
What effect does glucagon have on amino acid metabolism in the liver?
What effect does glucagon have on amino acid metabolism in the liver?
Signup and view all the answers
Which step does glucagon activate first in its mechanism of action?
Which step does glucagon activate first in its mechanism of action?
Signup and view all the answers
Which of the following correctly describes the release of insulin?
Which of the following correctly describes the release of insulin?
Signup and view all the answers
How does glucagon transduce its signal in target cells?
How does glucagon transduce its signal in target cells?
Signup and view all the answers
What is NOT a response associated with glucagon action?
What is NOT a response associated with glucagon action?
Signup and view all the answers
What type of molecule serves as a chemical messenger in cellular signaling?
What type of molecule serves as a chemical messenger in cellular signaling?
Signup and view all the answers
Which hormones are released in a coordinated manner to regulate blood sugar levels?
Which hormones are released in a coordinated manner to regulate blood sugar levels?
Signup and view all the answers
What initiates the signaling cascade upon insulin binding to its receptor?
What initiates the signaling cascade upon insulin binding to its receptor?
Signup and view all the answers
What is the primary metabolic effect of insulin on nutrient storage?
What is the primary metabolic effect of insulin on nutrient storage?
Signup and view all the answers
Which factor inhibits the secretion of insulin?
Which factor inhibits the secretion of insulin?
Signup and view all the answers
How does insulin influence glucose transport in muscle and adipose tissues?
How does insulin influence glucose transport in muscle and adipose tissues?
Signup and view all the answers
What role does glucagon play in the metabolic balance of nutrients?
What role does glucagon play in the metabolic balance of nutrients?
Signup and view all the answers
What is the approximate half-life of insulin in plasma?
What is the approximate half-life of insulin in plasma?
Signup and view all the answers
Study Notes
Cell Signaling Overview
- Cells communicate via chemical messengers
- These messengers are secreted in response to specific stimuli
- They travel to target cells and bind to specific receptors
- This binding elicits a response in the target cell
- The function of these messengers is to transmit messages between cells
Types of Cell Signaling
- Contact-dependent: Signaling cell and target cell are in direct contact via membrane-bound signal molecules
- Paracrine: Signaling cell releases local mediators that diffuse to target cells in close proximity
- Synaptic: Signaling cell (neuron) releases neurotransmitters across a synapse to a target cell
- Endocrine: Endocrine cells release hormones into the bloodstream that travel to target cells throughout the body
Cellular Response to Signals
- Cells can respond in diverse ways, depending on the specific signal and the target cell
- Examples of responses include: survival, growth and division, differentiation
- Also apoptosis (cell death)
Mechanism of Cell Signaling
- Fast signaling pathway (seconds to minutes): Extracellular signal molecule binds to cell-surface receptor, triggers changes in existing proteins, alters cell behavior quickly
- Slow signaling pathway (minutes to hours): Extracellular signal molecule binds to intracellular receptor, changes in protein synthesis, alters cell behavior more slowly
Chemical Messengers
- Any substance in an organism that is secreted from a cell in response to a specific stimulus
- Travels to a target cell and binds to a specific receptor in the target cell
- Elicits a response
- Function: Transmission of messages between cells
Types of Receptors
- Cell-surface receptors: Located on the cell membrane and bind to hydrophilic signal molecules
- Intracellular receptors: Located inside the cell and bind to small, hydrophobic signal molecules
Metabolic Effects of Insulin
- Production: Produced by beta cells in the islets of Langerhans in the pancreas
- Structure: Peptide hormone, half-life approximately 6 minutes
- Stimulated by: Glucose, amino acids, gastrointestinal peptide hormones
- Inhibited by: Conditions lacking dietary fuels, periods of physiological stress
- Effects: Promotes storage of nutrients (glycogen, TAG, protein); inhibits mobilization of stored nutrients
Mechanism of Insulin Action
- Binds to tyrosine kinase receptor
- Auto-phosphorylation initiates signaling cascade
- Promotes movement of GLUT-4 glucose transporters to cell membrane
- Increased glucose uptake, enzymatic activity changes over time
- Receptor regulation: internalization and degradation
Metabolic Effects of Glucagon
- Production: Produced by alpha cells in the islets of Langerhans in the pancreas
- Structure: Peptide hormone, short half-life
- Stimulated by: Low blood glucose, amino acids, catecholamines
- Inhibited by: High blood glucose, insulin
- Effects: Promotes glycogenolysis, gluconeogenesis, ketogenesis; inhibits lipid synthesis; increases amino acid uptake by the liver
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the intricate world of cell signaling in this quiz. Understand the various types of signaling mechanisms, including contact-dependent, paracrine, synaptic, and endocrine. Discover how cells communicate and respond to stimuli through chemical messengers.
