Tag Archives: physiology

At last…

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And so, a happy ending.

It always makes me smile to see things work out.

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Posted by on February 24, 2016 in Uncategorized


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Resurfacing: Reeeenal Physiooology. Creepy…


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Tune in next time when we find out if this will be old dotty great aunt Bedelia’s only stop…

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Posted by on February 18, 2016 in Uncategorized


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Invitation to submit questions for Renal System Exam … and a quick extra credit opportunity

As always, I invite students and non-students to submit multiple choice questions appropriate for the upcoming exam on the Renal System (Physiology and Pathophysiology questions). Post questions with answers (three wrong and one right) in the comments section below.

Also, here’s an opportunity for two points of extra credit on the upcoming exam:

Submit your answer quick – only the first correct response (also posted in comments) earns points. I will try to post several more questions over the weekend – note, these extra credit vignettes may come from any of the chapters we studied this semester)


A 62 year old man presented at the ER with sudden sensation of food being caught in his throat while swallowing. The patient is highly agitated and convinced he is choking although he appears to be getting air.

LESAn emergency endoscopy reveals food stuck in the esophagus. With pressure, food bolus passed into the stomach successfully. A subsequent barium swallow and X Ray produced the image here.

What is the diagnosis?


Posted by on April 24, 2015 in Uncategorized


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Invitation to Submit Questions for Respiratory Unit

As I’ve been doing lately, I wanted to offer the opportunity to my students (and anyone else who would like to) to submit questions for the Respiratory Unit Exam of my Pathophysiology class. Topics covered on this exam will focus primarily on the outline below. However, I wish to remind students that they are responsible for all the material covered in chapters 21-23 of Porth’s Essentials of Pathophysiology.

Airways preserved in the right lung, airways and pulmonary circulation in the left lung.

Airways preserved in the right lung, airways and pulmonary circulation in the left lung.

To submit questions, please provide a fully worked out multiple choice question in the comments section below. Also indicate the correct answer.

Respiratory Pathophysiology Outline (Please, forgive the formatting below, I’m having trouble fixing this appropriately in the browser):

  1. Control of Respiratory Function
    1. Conducting Airways
      1. Nasopharynx
      2. Larynx
  • Trachea
  1. Bronchial Tree (Primary -> Terminal)
  1. Respiratory Tissue (Acini)
    1. Respiratory Bronchiole
    2. Alveoli
      1. Type I, Type II Alveolar Cells and Alveolar macrophages
    3. Pulmonary (And Bronchial) Circulation
    4. Pleura
    5. Ventilation and the Mechanics of Breathing
      1. Chest Cage and Respiratory Muscles
      2. Lung Compliance
    6. Lung Volumes and Capacities
      1. Total Lung Capacity
      2. Tidal Volume
  • Etc.
  1. Diffusion according to Fick’s Law
  2. Oxygen Delivery
    1. Oxygen / Globin Dissociation Curves
  3. Infections
    1. The Common Cold
      1. Caused by a number of different viruses
      2. A number of different serotypes
    2. Influenza
      1. One of the most deadly uncontrolled human infections
      2. Three types of influenza (A,B, and C – A is most diverse)
        1. Influenza A
          1. Distinguished by serotypes based on H&N genes
  • Three types of infections
    1. Uncomplicated upper respiratory disease
    2. Viral Pneumonia
    3. Viral Pneumonia + Bacterial Pneumonia
  1. Pneumonia
    1. Typical*
      1. Bacterial ( pneumoniae)
    2. Atypical*
      1. Viral (Influenza, Chickenpox), Fungal, protozoan
  • Legionnaire’s Disease
    1. (I find that pneumonia caused by Legionella is placed as either typical or atypical depending on the source)
  1. Fungal Infections
  2. Tuberculosis
    1. Diagnosis
    2. Treatment
  3. Congenital and Acquired Obstructive Disorders
    1. CF
    2. Asthma
    3. COPD
    4. Pulmonary Hypertension – causes and outcomes

*The distinction between Typical and Atypical pneumonia appears to be more historic than clinically valuable. For this reason, on our exam we will continue to call S. pneumoniae the most common form of ‘Typical’ pneumonia, but otherwise not use these terms.


Posted by on March 4, 2015 in Uncategorized


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Pulmonary Anatomy and Physiology

Chapter 21 of Carol Porth’s Pathophysiology presents an introduction to respiratory anatomy and physiology. The following two chapters present pathologies that affect the system. I’ve outlined here the basics of lung A&P as notes from my reading of the chapter and I thought I would present that here as a guide for any of my students. I have yet to outline the second and third chapters, but there is a skeleton of conditions that we will cover. It is also worth noting that I expect my students to be able to recognize and identify the structural components of the respiratory system even though I did not include these elements in my outline …

Pulmonology Outline

  1. Structures and Functions (Chapter 21)
    1. Structures
      1. Upper Respiratory System
      2. Lower Respiratory System
  • Tissue and Cell types
    1. Ciliated columnar epithelial cells
    2. Goblet cells
  1. Alveoli – terminal air spaces in the lung & site of gas exchange
    1. Type I Alveolar Cells – this squamous cells making up ~95% of the alveolus
    2. Type II Alveolar Cells – secretory cells that produce surfactant, also serve as progenitors of Type I cells
    3. Alveolar Macrophages – responsible for removing organisms and debris that penetrated the lungs
  2. Pleura – a double layer of membrane lining the inner thoracic cavity and covering the lungs.
  1. Functions
    1. Conducting Airways
      1. Purpose: To deliver warm, moistened, cleaned air to Respiratory Tissue
    2. Respiratory Tissue: To perform gas exchange (O2 and CO2)
  • Gas Exchange
    1. Ventilation – Inspiration and Expiration
      1. Mechanically, ventilation depends upon the structure of chest cavity – i.e. it is entirely closed with the only opening to the exterior being the trachea
      2. Inspiration occurs as the diaphragm pulls down and opens the
    2. Perfusion – flow of blood through the alveolar capillary bed

Ventilation and Perfusion must be matched in order to optimally oxygenate blood in the lungs.

  1. Gas exchange (described by the Fick Law of Diffusion)
    1. V = [SA x KD (P1-P2)] / T
    2. Both O2 and CO2 are transported by blood
  2. Hb Dissociation Curve
  3. Partial Pressure – the pressure of some component of a gas. By definition, all partial pressures add up to the total pressure of a gas. (i.e. if a gas is comprised of O2 and CO2, then the partial pressures of O2 and CO2 must add up to the total pressure of the gas)
  4. The O2 / Hb dissociation Curve
    1. Measures the amount of O2 bound to Hb at any specific PO2
  5. Lung Volumes & Capacities (summarized in Table 21-1)
    1. Tidal Volume – volume of air going in and out of the lungs with each resting breath
    2. Total Lung Capacity (TLC) = tidal + inspiratory reserve + expiratory reserve + residual volumes
    3. Vital Capacity = tidal + inspiratory + expiratory reserve volumes
    4. Dead Air Space – Air in the lungs that does NOT participate in respiration


  1. Why is arterial (rather than venous) blood used to measure blood gases?
    1. What would venous blood gases measure?
  2. Using an O2 / Hb dissociation curve, show how Hb effectively carries O2 from the lung to the muscles, where it is released to myoglobin for use in respiration.


  1. General Issues
    1. Pleura effusions– are accumulations of fluid in the space between the pleural membranes around the lungs
    2. Infant Respiratory Distress Syndrome – alveolar collapse in young infants (esp prematures) due to lack of surfactant
    3. Dyspnea – general term for difficulty breathing. Can occur due to primary lung disease, heart disease, or neuromuscular disorders affecting the respiratory muscles
  2. Infections
    1. Pneumonia
    2. Influenza
    3. Fungal Infections
    4. Tuberculosis
  3. Congenital Problems
    1. CF
  4. Acquired Problems
    1. COPD
    2. Pulmonary Hypertension – causes and outcomes
  5. Respiratory Distress Syndrome
  6. Respiratory Failure
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Posted by on February 23, 2015 in Uncategorized


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The Hardest Working Organ of the Body

Like the James Brown of the Body

As I started grading the first Pathophysiology Exam on Cardiovascular Function in Health and Disease, the first material I saw was in answer to my questions about the flow of blood through the heart and to the rest of the body. I can’t say that I was happy with the results, but I want to emphasize that this is very basic material that we discussed and outlined in our class, but that I had also assumed was covered in Anatomy and Physiology last semester. After two passes through this material, it should be easily accessible in every student’s mind.

As a reminder of these functions and the flow of blood, here is Khan Academy’s summary of this material:

I believe that that is important foundational material, and you may have a pop quiz on it at any time.

stay on the scene

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Posted by on February 21, 2015 in Uncategorized


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Pathophysiology Exam Coming up

Riddle_Me_This...My Pathophysiology class is having its first exam coming up soon (February 19th) and it’s time to solicit questions for the exam. Really, this is for my students, however, if non-students want to contribute questions, I’ll entertain those too.

Qualifications to be accepted:

1. Be a well-phrased question with a clear answer (this is helped somewhat by #2)

2. Provide four or five answers (for multiple choice) to the question and indicate which one is correct.

3. Be on topic (i.e. regarding the basic anatomy and physiology of the cardiovascular system, peripheral vascular disease, defects of the heart (congenital), valvular disease, hypertension, or myocardial infarction – other topical questions will be considered, but may appear as extra credit if they were not covered in class)

4. Post here as a reply to this blog entry so that it is visible to others.


Posted by on February 12, 2015 in Uncategorized


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Getting Oxygen Where It’s Needed

Getting Oxygen Where It’s Needed.

This is an older post of mine that I thought I should point back to because my general biology class is now covering cellular respiration.

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Posted by on October 3, 2013 in Education


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