Introduction to Physiology for Bioengineers — Lecture Notes (Dr. Kelly Marble)

Instructor and Course Context

• Dr. Kelly Marble, Associate Lecturer, Department of Bioengineering, University of Toledo (UToledo).
• This is her eleventh year on faculty at UToledo.
• Course focus: physiology and anatomy for bioengineers; emphasis on questions-based learning.
• Schedule context: lectures typically on Mondays and Wednesdays; attendance and travel logistics discussed (students may be coming from nearby campuses or across Douglas).

Syllabus, Attendance, and Technology

• Attendance tracking discussed using QR codes and Microsoft Forms via OneDrive; authentication may require a verification call (multi-factor authentication).
• If attendance capture fails, a sign-in sheet will be used.
• Question: how many students have electronics available for in-class work; logistics for students arriving late or from off-site.
• Emphasis on upfront attendance questions and end-of-class questions.
• Open door to adjust logistics if class timing or attendance method changes.

Instructor Personal Update and Availability

• Personal note: welcomed third child (Addison) in the spring; pictures shared.
• Availability: posts notes on Blackboard; non-recorded lectures; expects students to use Blackboard for communications.
• Office hours: times to be set; email preferred for questions, especially before exams or homework.
• Counseling on travel or remote lectures: if not in office, arrangements can be made; if times don’t work, plan alternate meetings.

Course Platform and Textbook

• Blackboard Ultra in use; some items may be hidden from students by default and need manual visibility.
• Textbook switched editions; ISBN listed on syllabus; students may obtain from various sources (campus bookstore, online providers, etc.).
• Reading: weekly suggested topics/pages to read from an 8th edition; class focuses on core topics and notes posted by instructor.
• Supplemental images in the textbook used for background, not required to cover all 981 pages in a single semester.
• Notes posted on Blackboard take precedent over the textbook for class content.

Academic Policies and Integrity

• Standard academic policies: no cheating; integrity emphasized; consequences for misconduct.
• Attendance counts toward grade; there are built-in penalties for excessive absences.
• Absent students are still responsible for content covered;
• No recording of lectures.
• Homework purpose: reinforce topics and help study for exams; not a substitute for in-class learning.
• Collaboration allowed on homework; but must be individual work submitted honestly (no copying or use of generative AI to produce work).
• If something goes wrong with an assignment, policy details and procedures are provided, including how to handle academic misconduct concerns.

Course Logistics and Prerequisites

• Target audience: students who have taken BIO 2.0, BIO 2 Lab, General Chemistry II, and presumably Circuits; Circuits is an older prereq but can be taken concurrently.
• Electrical concepts will be aligned with physics (Physics II is prereq for electronic circuits).
• The course integrates biology background with engineering math and bioengineering context; emphasis on physiology with some anatomy context.

Course Materials and Reading Strategy

• Textbook: 8th edition; ISBN on syllabus; choice of procurement source.
• Instructor will post suggested topics/pages; focus is on what is covered in class and notes.
• The notes take precedence over textbook content for the course’s learning objectives.

Exams and Grading Structure

• Assessments include homework, quizzes (potential), attendance/participation, two exams, and a final.
• Attendance/participation is worth 10% of the final grade.
• Exams: two in-class exams plus a final; total exam-related weight = 66\%\ (two exams and final); each of the two in-class exams contributes a substantial portion, with the final contributing the remaining portion to reach 66% together.
• Final exam date is fixed by university schedule; two earlier exams may be rescheduled tentatively if needed to accommodate students’ other courses, but the final is set.
• Grading scale used is strict; instructor considers occasional poor exam performance if there is overall engagement and mastery demonstrated across other components.
• Homework and quizzes: intended to guide study and identify topics needing more focus; the instructor may adjust weights if a student performs poorly on one exam but shows engagement.
• Exams are closed-book; designed to assess demonstration of mastery rather than recall of notes.

Office Hours and Communication

• Primary contact method: email; phone number provided with voicemail and email forwarding.
• Typical response: within the next business day; during peak times around exams, emails may be answered until 9:00 PM as a courtesy.
• In-person meetings: available during office hours; alternative arrangements possible if times don’t work.
• Personal note: instructor has three young children; requests understanding about late-evening responses.

Accessibility and Accommodations

• Academic accommodations available via Accessibility and Disability Resources; discuss accommodations ahead of exams.
• Religious accommodations: up to three days per academic semester for religious observances; process documented on university pages; students should coordinate with university for official approvals.

Tentative Schedule and Course Timeline

• Schedule is tentative and subject to change based on pacing and student needs.
• Text and topics span approximately twenty-one chapters; early chapters are review; some prerequisites may be revisited.
• Homework plan: instructor references potentially about 10 homeworks; actual number may vary; plan is to overpromise but maintain feasibility.
• Exam timing: first exam around September for chapters 1–6; second exam around November 4; final exam during finals week (date/time set by university; typical time slot discussed).
• Breaks and holidays are highlighted in yellow on the schedule; plan may move deadlines if breaks occur.

Core Concepts in Physiology (Four Major Themes)

• Four major themes used to investigate and understand physiological systems:
  • Structure–function relationships: how tissue and organ structure determines function; example: RBC shape and hemoglobin function.
  • Energy transfer and use: energy input, storage, and utilization in growth, reproduction, movement, and cellular maintenance.
  • Flow of information: genetic to protein synthesis, intercellular signaling (chemical and electrical), and cross-system communication.
  • Homeostasis and control of physiological processes: maintaining a stable internal environment via regulatory mechanisms.

What is Physiology? (Foundational Definitions)

• Physiology defined as the normal functioning of a living organism and its parts, including a range of normal variation within a population.
• Levels of organization: molecules → cells → tissues → organs → organ systems → organism.
• Emphasis on molecules, cells, and organ systems; integration across systems (cardiovascular, respiratory, renal, digestive, etc.).
• Important idea: not all topics are required to be learned in depth; the goal is functional understanding and integration, especially relevant for bioengineers designing interfaces with human biology.

Function vs Mechanism (Teleological vs Causal)

• Teleological (functional) question: Why does red blood cell transport oxygen? (Cells need oxygen; what’s the purpose?)
• Mechanistic (how) question: How do red blood cells transport oxygen (hemoglobin binding, transport within cells)?
• For engineers, linking function and mechanism helps identify where to intervene with design solutions to restore health or improve performance.
• Example tie-in: oxygen transport requires hemoglobin; RBCs carry oxygen; diffusion alone is insufficient for rapid transport; RBCs enable efficient oxygen delivery to tissues.

Structure and Function (Molecular to Organ Level)

• Protein shape determines function; single amino acid changes can cause diseases (e.g., sickle cell anemia): misfolded hemoglobin leads to altered RBC shape and impaired oxygen delivery.
• Cellular compartmentalization: organelles like mitochondria (energy production) enable specialized cellular tasks; mitochondria are essential for ATP generation.
• Body cavities and compartmentalization: kidneys, brain, thoracic/abdominal cavities illustrate functional separation and specialization.
• Implication for bioengineering: intracellular and extracellular environments must be considered when designing implants or therapies.

Energy in Physiology

• All life processes require energy; includes growth, movement, transport, and maintenance of homeostasis.
• Energy sources in humans: carbohydrates, fats, proteins; vitamins and minerals support cellular function.
• Energy flow concepts: building and breaking down molecules require energy; transport across membranes and creation of movement require energy.
• Genetic information ties to energy and function: DNA → RNA → proteins; proteins are central to biological solutions and engineering interventions.

Information Flow and Cellular Communication

• Cell-to-cell communication occurs via chemical signals and electrical signals; both local (neighboring cells) and long-distance signaling are essential.
• Local control vs reflex (long-distance) control: local direct responses vs integrated systemic responses.
• Example of local control: hypoxic tissue releases signals causing vasodilation to increase blood flow in the affected area.
• Example of reflex control: endocrine signaling where glucose intake triggers pancreatic insulin release to regulate blood glucose.
• In engineering terms: input signal → processing/integration → output response; a damaged controller leads to diminished or absent responses.

Homeostasis, Mass Balance, and Compartments

• Homeostasis: relatively stable internal environment; ranges rather than single values define normalcy (e.g., pH, heart rate, blood glucose).
• Mass balance: input vs. output over time; steady state implies input equals output for the substance of interest.
  • Example mass balance: glucose intake vs. glucose utilization/excretion.
  • Steady state: no net change in compartment composition over time, though molecules continue to move (flux).
• Compartments in physiology:
  • Extracellular fluid (ECF): fluid outside cells but inside the organism.
  • Intracellular fluid (ICF): fluid inside cells.
  • External environment: far outside the body, interacts via external interfaces (airways, skin, GI tract).
• Mass flow concepts: rate of transport (e.g., grams per minute, moles per hour) and clearance concepts.
• Clearance (definition and usage): volume of blood cleared of a substance per unit time; formula relates elimination rate to plasma concentration:
  • Cl = \frac{\text{Elimination rate (mass/time)}}{C_{plasma}}
  • Units: L/time; used to quantify kidney or liver clearance (e.g., for a drug).
• Routes of elimination: kidneys and liver are primary; lungs can eliminate compounds like CO2 and some volatile substances; skin and sweat can also contribute; exhaled compounds (e.g., garlic breath, alcohol) illustrate additional clearance routes.
• Relevance for health monitoring: mass flow and clearance can be used to monitor health status or exposure to compounds; not always about treatment—sometimes about monitoring.
• Equilibrium vs steady state vs mass balance:
  • Equilibrium: identical compositions between compartments (not the goal in physiology).
  • Steady state: stable compositions with ongoing movement; input and output balanced for the substance of interest.
  • Mass balance: accounting of gains and losses (inputs vs outputs) over time to maintain homeostasis.

Control Systems in Physiology

• Communication across the body: input signal → processing/center → output response; involves local control and reflex control (long-distance signaling).
• Examples:
  • Local control: tissue oxygen levels cause local vasodilation to increase blood flow in the area.
  • Reflex control: endocrine example where glucose increase triggers insulin release to regulate blood sugar.
• Controller integrity: if the integrating center (controller) is damaged, output may be diminished or absent; understanding this helps in designing interventions.
• Negative vs positive feedback:
  • Negative feedback: restores homeostasis; stimulus is reduced or eliminated to maintain set point (thermostat-like behavior).
  • Positive feedback: amplifies a stimulus; example in childbirth where contractions escalate; usually requires an external event to terminate the loop.
• Feed-forward control: anticipatory responses that prevent disruption before it occurs (e.g., salivation and gastric acid secretion in anticipation of meals).

Classic Feedback Examples and Implications

• Negative feedback example: thermostat; cold triggers heating, once set point is reached, heating stops.
• Positive feedback example: childbirth; cervical dilation triggers hormonal cascade that increases contractions, culminating in birth; requires external trigger to terminate.
• Feed-forward example: preparation for meals; salivation and gastric acid secretion occur in anticipation of food.

Circadian Rhythms and Biological Timing

• Circadian rhythm: a 24-hour cycle affecting temperature, hormone levels (e.g., cortisol, growth hormone), and other physiological processes.
• Timing matters for clinical measurements (e.g., ordering plasma cortisol or growth hormone tests depends on the time of day).
• Environmental cues such as light exposure influence circadian rhythms; acclimation to environments (temperature and light) can alter set points and physiological responses.

Real-World Connections and Engineering Perspective

• Understanding physiology from an engineering lens helps identify where to intervene with devices or treatments (e.g., pacemakers, prosthetics, biomaterials).
• The integral role of proteins, genetics, and signaling in enabling biomedical solutions; proteins are the fundamental units for engineering biological solutions.
• Recognition that a patient’s physiology is an integrated system; modifications in one system affect others (e.g., immune response implications for biomaterials and tissue engineering).

The Bottom Line and Exam Readiness

• Emphasis on how systems interconnect, rather than memorizing isolated facts.
• Core learning objectives include understanding homeostasis, energy transfer, structure–function relationships, and information flow in physiology.
• Students should be able to discuss: roles of compartments, mass balance, clearance, and different control mechanisms; apply these concepts to physiological scenarios and potential engineering interventions.

Quick Reference: Key Equations and Concepts

• Homeostasis and set points: a stable internal environment with acceptable ranges; example: pH range of human blood:
  • 7.2 \le \text{pH} \le 7.4
• Mass balance (steady state): input = output for the substance in question.
  • \text{Input} = \text{Output} \quad (\text{steady state})
• Mass flow (transport rate):
  • (\text{Flow} = \text{Concentration} \times \text{Volume flow}
  • Used in context of kidney filtration, liver clearance, and systemic transport.
• Clearance (volume of plasma cleared per unit time):
  • Cl = \frac{\text{Elimination rate (mass/time)}}{C_{plasma}}$$
  • Units: L/time

Notable Names and Concepts Mentioned

• RBCs and hemoglobin: oxygen transport, effect of sickle cell mutation on structure and function.
• Mitochondria: cellular energy production and ATP generation.
• Proteins: single amino acid changes can drastically alter function; fundamental to biology and engineering design.
• Extracellular vs intracellular fluids: fluid compartments essential for signaling and transport.
• Local control vs reflex control vs feed-forward control: different scales and speeds of physiological regulation.
• Circadian biology: daily rhythms affecting hormone levels and physiology.

Practical Implications and Ethics

• Academic integrity emphasized; cheating not tolerated; exams closed-book.
• Attendance policy integrated into grading; absences require acknowledging content coverage; there is no incentive to fake attendance.
• Accommodations for disabilities and religious observances are supported; students should engage with university processes to arrange accommodations.
• The course aims at enabling engineering solutions to physiological problems while acknowledging clinical boundaries (diagnosis and treatment remain outside the engineer’s remit).

Connections to Previous Courses and Real-World Relevance

• References to BIO 1200 and Biotransport (BIOE 3XXX) for context on transport and oxygen delivery.
• Circuits and Physics II prerequisites link electrical concepts to bioengineering applications (e.g., electrical signaling, medical devices).
• Relevance to senior design and biomaterials, given immune system considerations and the importance of designing devices that interface safely with human physiology.

Questions to Focus Your Study On

• How do the four major themes of physiology interrelate in a single organ system (e.g., cardiovascular and respiratory interactions)?
• Can you explain the difference between steady state and equilibrium, and why steady state is the physiologically relevant concept?
• How does mass balance inform understanding of a drug clearance or a renal/hepatic function test?
• What would be an engineering approach to a problem where a negative feedback loop is malfunctioning? When would a feed-forward strategy be advantageous?
• How do circadian rhythms affect the interpretation of clinical measurements and the design of experiments in physiology?

Summary Takeaway

• This course emphasizes an integrated, systems-based view of physiology tailored to bioengineering: understanding structure–function relationships, energy flows, signaling and information transfer, and regulatory mechanisms that maintain homeostasis. The instructor highlights practical course logistics, expectations around integrity, and the real-world relevance of physiology to engineering solutions and medical technologies.