Podcast
Questions and Answers
What is the definition of homeostasis?
What is the definition of homeostasis?
Homeostasis is the regulation of an organism's internal environment to maintain a stable state within a narrow range.
What are the two main fluid compartments in the body, and what is their typical relative volume?
What are the two main fluid compartments in the body, and what is their typical relative volume?
The two main fluid compartments are the intracellular fluid (ICF) and extracellular fluid (ECF). ICF accounts for around 2/3 of the total body water while ECF accounts for 1/3.
Which of the following is NOT one of the core concepts in physiology as outlined by Michael and McFarland (2011)?
Which of the following is NOT one of the core concepts in physiology as outlined by Michael and McFarland (2011)?
Which of these is a teleological approach to physiology?
Which of these is a teleological approach to physiology?
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Which of the following is an example of an anticipatory response in the body?
Which of the following is an example of an anticipatory response in the body?
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What is the primary function of the nervous system in regulating homeostasis?
What is the primary function of the nervous system in regulating homeostasis?
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What is the main difference between negative and positive feedback loops?
What is the main difference between negative and positive feedback loops?
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Hormones are the only way that the endocrine system can regulate homeostasis.
Hormones are the only way that the endocrine system can regulate homeostasis.
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How is the body's internal environment separated from the external environment?
How is the body's internal environment separated from the external environment?
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The body's internal environment includes both interstitial fluid and plasma.
The body's internal environment includes both interstitial fluid and plasma.
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Which of the following is NOT a component of the negative feedback loop?
Which of the following is NOT a component of the negative feedback loop?
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Give an example of a negative feedback loop in the body.
Give an example of a negative feedback loop in the body.
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Match the following terms with their correct definitions:
Match the following terms with their correct definitions:
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Study Notes
Physiology 3051 - Introduction
- Course name: Physiology 3051
- Instructor: Joe Sepe, PhD
- Date: September 4, 2024
Welcome
- Instructor: Dr. Joe Sepe
- Email: [email protected]
- Office: Jackson Hall 6-130
- Office Hours:
- Mondays: 2-3 pm, Jackson Hall 3-129
- Wednesdays: 2:30-3:30 pm, lab classroom (4-115 PWB)
- Contact via email, Zoom, or in person
Session Learning Objectives
- Define homeostasis and explain how the internal environment is regulated through negative feedback.
- Differentiate between negative and positive feedback mechanisms, and contrast feedforward regulation.
- Differentiate between the teleological (the "why") and the mechanistic (the "how") approaches to physiological processes.
- List the two major fluid compartments in the body and the typical (relative) fluid volumes in each compartment.
- Describe the levels of organization for cells, tissues, and organs.
What is Physiology?
- Physiology is the study of the normal functioning of a living organism, from molecules to organs and organ systems.
- The basis of medical practice. Pathophysiology describes disease which requires a strong foundation in normal, healthy function (physiology).
Function and Mechanism
- "Why" versus "How":
- Function: Explains the reason for a process, often at a higher level (teleological). Example: Why do kidneys produce concentrated urine? Maintaining water balance on land is a challenge.
- Mechanism: Explains how a process works, typically at the cellular level (mechanistic). Example: How do kidneys produce concentrated urine? Membrane transport and selective permeability.
- Our goal: Understand both the function and mechanisms of biological processes, in health and disease.
Core Concepts of Physiology
- Evolution
- Homeostasis
- Causality
- Energy
- Structure/Function
- Cell theory
- Levels of organization
- Cell-cell communication
- Cell membrane
- Flow down gradients
- Genes to proteins
- Interdependence
- Mass balance
- Physics/Chemistry
- Scientific reasoning
Organism Body Plans: Homeostatic Challenge
- Simple organisms (single cell or two-layer) rely on diffusion across a single membrane for homeostasis.
- Complex organisms (like humans) maintain internal stability through organ systems and separate layers (membrane).
Cells, Tissues, Organs, and Organ Systems
- Levels of organization: Cells (smallest living cells):
- Nerve Cells
- Muscle cells (skeletal, smooth, cardiac)
- Epithelial Cells
- Connective Tissue Cells
A Simplified Body Plan
- External and Internal Environments are separated by epithelial membranes creating a continuous barrier to separate environments.
External and Internal Environments
- External Environment: Surrounding the body (e.g., air, food).
- Internal Environment: Immediate environment of most cells.
- Extracellular Fluid (ECF) includes plasma (fluid around blood cells) and interstitial fluid (fluid around other cells).
Body Fluid Compartments
- Fluid compartments: Plasma(3.1L), Interstitial Fluid(11), Intracellular Fluid (26L)
Homeostasis
- Regulation of an organism's internal environment.
- Constant internal environment is compatible with cell survival.
- Relies on organ systems that detect and respond to deviations in physiological variables from their "set point" values
Systemic, Diffuse Response Regulated by Two Control Systems: Nervous and/or Endocrine Systems
- Nervous System: Brain, spinal cord, nerves, ganglia.
- Endocrine System: Hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pancreas, ovaries, testes.
Speed of Action: Endocrine System
- Slower response (minutes to hours, even longer)
- Diffuse targets; impacting whole tissues or organ systems.
Speed of Action: Nervous System
- Very fast response (milliseconds)
- Regulates functions using negative feedback, regardless of the speed.
Terms and Components of Negative Feedback Control System in Homeostasis
- Stimulus: Initial change. Example: Blood sugar changing.
- Receptor: Detects changes in the stimulus, compared to a set point.
- Afferent pathway: Information to Integrating center (brain).
- Integrating center: Compares change to a set point and determines an appropriate response.
- Efferent pathway: Information sent from Integrating center to Effector.
- Effector: Sends response to the system to reverse/compensate the change.
- Response: Reverses/compensates for the stimulus.
Negative Feedback Example: Blood Glucose
- Maintaining blood sugar (glucose) within a certain range. If blood glucose increases, the response is to decrease blood glucose.
List the components of a Feedback Loop
- Stimulus
- Receptor
- Integrating Center
- Effector
- Response
Positive Feedback Loops
- Reinforces the initial stimulus.
- Common example: childbirth (uterine contractions, oxytocin).
Feedforward Control
- Anticipatory response to change.
- Example: Increased saliva production anticipating a meal.
- Other examples: Cardiovascular changes before exercise; skin temperature changes in anticipation
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Description
Test your knowledge on the foundational concepts of Physiology 3051, including homeostasis, feedback mechanisms, and fluid compartments. This quiz will assess your understanding of both teleological and mechanistic approaches to physiological processes. Prepare to engage with key learning objectives from the beginning of the course.
