Podcast
Questions and Answers
Which of the following statements about classical hormones is true?
Which of the following statements about classical hormones is true?
What distinguishes endocrine signaling from synaptic signaling?
What distinguishes endocrine signaling from synaptic signaling?
Why must hormones act at very low concentrations in the bloodstream?
Why must hormones act at very low concentrations in the bloodstream?
Which of the following best explains the affinity of target cell receptors for hormones?
Which of the following best explains the affinity of target cell receptors for hormones?
Signup and view all the answers
Which of the following is NOT considered a classical hormone producer?
Which of the following is NOT considered a classical hormone producer?
Signup and view all the answers
Which characteristic is NOT associated with endocrine hormones?
Which characteristic is NOT associated with endocrine hormones?
Signup and view all the answers
Which statement correctly describes the relationship between hormones based on their interaction effects?
Which statement correctly describes the relationship between hormones based on their interaction effects?
Signup and view all the answers
What distinguishes neurotransmitters from neurohormones?
What distinguishes neurotransmitters from neurohormones?
Signup and view all the answers
Which of the following classes of hormones is synthesized from cholesterol?
Which of the following classes of hormones is synthesized from cholesterol?
Signup and view all the answers
Which class of hormone is primarily composed of amino acids and acts on receptors located on the cell surface?
Which class of hormone is primarily composed of amino acids and acts on receptors located on the cell surface?
Signup and view all the answers
How do antagonistic hormones function in the body?
How do antagonistic hormones function in the body?
Signup and view all the answers
What distinguishes steroid hormones from peptide hormones in terms of their synthesis and release?
What distinguishes steroid hormones from peptide hormones in terms of their synthesis and release?
Signup and view all the answers
What is a key mechanism by which steroid hormones exert their effects inside target cells?
What is a key mechanism by which steroid hormones exert their effects inside target cells?
Signup and view all the answers
How do peptide hormones differ from amino acid hormones in terms of their size and storage properties?
How do peptide hormones differ from amino acid hormones in terms of their size and storage properties?
Signup and view all the answers
Which statement correctly describes the action of amino acid hormones like epinephrine?
Which statement correctly describes the action of amino acid hormones like epinephrine?
Signup and view all the answers
What role does Hsp90 play in the mechanism of steroid hormone action?
What role does Hsp90 play in the mechanism of steroid hormone action?
Signup and view all the answers
What is the defining characteristic of the endocrine system compared to other forms of cell communication?
What is the defining characteristic of the endocrine system compared to other forms of cell communication?
Signup and view all the answers
Which of the following correctly describes the specificity of paracrine signaling?
Which of the following correctly describes the specificity of paracrine signaling?
Signup and view all the answers
What does the Greek origin of the word 'endocrine' signify?
What does the Greek origin of the word 'endocrine' signify?
Signup and view all the answers
What common property do all hormones in the endocrine system share regarding their effects?
What common property do all hormones in the endocrine system share regarding their effects?
Signup and view all the answers
Which class of signaling is characterized by messages transmitted directly between nearby cells?
Which class of signaling is characterized by messages transmitted directly between nearby cells?
Signup and view all the answers
Study Notes
BMN 1002 Cell Biology - Lecture 25: Introduction to Endocrinology
- Lecture focused on the introduction to endocrinology
- Recommended textbook: "The Endocrine System" by Joy Hinson, Peter Raven, and Shern Chew (2nd Edition) and "Human Physiology" by Dee Unglaub Silverthorn (4th Edition)
- Learning outcomes include defining the endocrine system and hormones, listing different hormone classes and their properties, explaining hormone action via receptors and feedback mechanisms regulating hormone secretion.
Mode of Communication
- Gap junctions: message transmitted directly between cells; specificity depends on anatomical location (e.g., heart).
- Synaptic: message transmitted across the synaptic cleft; specificity depends on anatomical location and receptors.
- Paracrine/Autocrine: message transmitted locally by diffusion in interstitial fluid; specificity depends on receptors.
- Endocrine: message transmitted by circulating body fluids (bloodstream); specificity depends on receptors.
Endocrine Glands and Hormones
- Endocrine glands produce hormones for both local and distant effects.
- Classical endocrine glands: pineal, hypothalamus, pituitary, thyroid, parathyroids, thymus, adrenals, pancreas, ovaries, testes
- Non-classical endocrine producers: kidney, heart muscle, adipocytes, endothelium, platelets.
- The endocrine system involves the release of hormones into the bloodstream acting on distant cells.
- Hormones are chemical messengers synthesized by specialized cells in small amounts to regulate cellular function in target organs.
Hormones, Receptors, and Actions
- Hormones act on specific receptors located on the cell surface or within the cell.
- High affinity: hormones are effective at low concentrations.
- Synergistic: two hormones have a greater combined effect than one alone.
- Permissive: presence of one hormone is necessary for another to have a full effect.
- Antagonistic: two hormones oppose each other's effects; hormones compete for the same receptor.
- Competitive: two hormones similar in structure compete for the same receptor.
Classifications of Hormones
- Hormones classified into three groups based on chemical structure:
- Steroids: synthesized from cholesterol; act on intracellular receptors, slow but long-lasting effects
- Peptides/Proteins: synthesized from amino acids; act on cell surface receptors.
- Amino acids: e.g., thyroid hormone; synthesized from tyrosine, variable mechanisms of action in the cell
Hormone Signaling-Peptide and Amino acid Hormones
- Action via second messengers like cAMP, IP3 pathways triggering rapid or long-term responses.
- Includes catecholamines, ACTH, FSH, LH, and others
- Mechanisms for hormone release include continuous (e.g., thyroid hormones), pulsatile (e.g., growth hormone), circadian (e.g., melatonin), and exocytosis on stimulus (e.g. insulin).
- Hormone activation includes structural alteration (e.g. vitamin D), degradation, receptor down-regulation, termination of intracellular effects, and negative feedback.
- Mechanisms of negative feedback involve the regulated metabolite (like glucose and insulin) , the hormone itself (like cortisol), and the trophic hormone from the pituitary.
Hormone Signaling-Steroid Hormones
- Steroids pass through the plasma membrane (lipid-soluble) and act on intracellular receptors, which bind to DNA and regulate gene transcription resulting in slow but long-lasting effects.
- Include examples like corticosteroids and sex hormones.
Action on receptors and 2nd messengers: Peptide and amino acid hormones : cAMP and IP3.
- Receptors have different signaling pathways depending on the hormones involved resulting in both short and long term effects
Mechanisms for hormone release, activation, and feedback control
- Feedback mechanisms regulate hormones ensuring homeostasis
Integrated and Complex Systems
- The hypothalamic-pituitary-axis forms the centre of the complex system for integrating hormonal functions involving both short and long-loop feedback systems.
Attempt questions in VEVOX during the session
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fundamentals of endocrinology in this lecture focused on the endocrine system and hormones. Learn to define the endocrine system, differentiate hormone classes, and understand hormone action through various mechanisms. This quiz is essential for grasping the basics of cell signaling and its implications in biology.
