CQRG's Winter Medical Terminology Boot Camp
DAY 9 / IMMUNE SYSTEM AND RESPIRATORY OVERVIEW
Welcome to Day 9!
If you are new to our medical terminology program we invite you to click on the PROGRAMS tab above to view days 1-8. This short program will conclude tomorrow (Wednesday, January 1, 2025). But, don’t worry! Each lesson is designed to be a standalone experience, so you can catch up later. Subscribe to receive the lessons emailed to you, or follow along in the Notes section.
Introduction to the Immune System
The core function of our immune system is to prevent (or limit) infection.
The immune system developed over time to safeguard us against a vast array of ever-evolving microbes. The immune system is composed of innate (or, general) mechanisms and adaptive (or, specialized) ones. Additionally, these systems assist in the removal of toxic and allergenic substances that may infiltrate the body through mucosal surfaces.
Key term: mucosal
relating to mucous membranes;
a membrane rich in mucous glands;
example: the passages of the gastrointestinal and respiratory tracts
The Innate and Adaptive Immune Systems
The human body's innate immune system serves as the initial defense against invaders.
This system reacts in a uniform way to all pathogens and external agents. This is why it also known as the "non-specific" immune system.
Key term: innate immune system
body’s initial defense against infection and disease;
non-specific strategies
Features of the Innate Immune System
Non-specific:
Recognizes and reacts to common characteristics of various pathogens
Immediate:
Reacts rapidly. Often within minutes. Other components may take hours to identify and eradicate pathogens.
Physical barriers:
Barriers like the skin, mucous membranes, and other anatomical features serve as a physical defense against pathogens
Cellular components:
Dendritic cells, macrophages, neutrophils, and natural killer cells are some of the vital cellular elements involved in the innate immune response.
Cytokines:
Signaling molecules contribute to the coordination and regulation of responses.
Barriers to Infection
Barrier defenses, are key components of the body's innate defense mechanism.
Barrier defenses do not function as a reaction to infections; instead, they serve as safeguard against pathogens. They work by obstructing the entry of pathogens into the body, eliminating them once they have entered, or expelling them before they can establish a foothold.
Key term: barrier defenses
chemical and physical barriers that protect the body from external pathogens
Examples:
Skin:
Here highly keratinized cells on the surface layer are too dry for bacteria to grow well. They are being continuously sloughed off, along with the microbes on them.
Salivary Glands In The Oral Cavity:
These glands secrete an enzyme that destroys bacteria (lysozyme).
Stomach:
An extremely low pH creates an environment which is fatal to many pathogens.
Mucosal:
Able to trap debris and microbes. Facilitates removal.
Sweat and sebaceous glands of the skin:
Create a lower pH than microbes prefer.
Also contains substances toxic to pathogens
Physiologic Defenses
While our barrier defenses act as the initial physical line of defense against pathogens, innate immune responses serve as the primary physiological line of defense.
Infections may be rapidly and effectively controlled via innate immune responses. However, the actions of the innate immune system may fall short in fully halting pathogen proliferation. Even so, the system provides a window for adaptive immune responses to ramp up and take charge of suppressing or eradicating the pathogen.
A core function of the innate system is that it can signal cells of the adaptive immune system, instructing them on how to combat the pathogen.
The Adaptive Immune System
The adaptive immune system acts on invading microbes and/or substances directly.
If our non-specific defense mechanisms fail to eliminate a pathogen, the adaptive, or specialized system takes over. This system works to specifically target the type of invader causing the problem.
Adaptive immunity is a subsystem of the immune system composed of specialized, systemic cells and processes that work to neutralize pathogens and/or inhibit their growth.
The adaptive immune system responds to invaders in a highly precise manner. This response entails the identification of particular pathogens or antigens, as well as the mobilization of immune cells like T cells and B cells. By doing so, the adaptive immune system grants the body long-term immunity against specific pathogens, enabling it to retain a memory of previous infections and swiftly respond to future ones.
This lesson offers an introduction to the immune system and related medical terms. We encourage you to explore the supplementary videos that delve deeper into the subject matter. Furthermore, Medical Terminology for Healthcare Professions, (Chapter 11) offers a more comprehensive understanding of the function, structure, and vocabulary associated with both the lymphatic and immune systems.
Helpful Videos:
Introduction to the Respiratory System
The lungs are the main organs of the respiratory system.
The respiratory system is vital to receive oxygen and rid the body of carbon dioxide. It’s primary role is to supply oxygen to the body's tissues for cellular respiration, eliminate carbon dioxide waste, and assist in maintaining the acid-base equilibrium.
Key term: cellular respiration
process whereby cells acquire energy from glucose and other organic molecules in the presence of oxygen
Major Functions of the Respiratory System
The main function of the respiratory system is to breathe in oxygen and expel carbon dioxide.
By transporting blood to and from the lungs, the circulatory system (Medical Terminology Lesson 9) supports the respiratory system. The circulation helps carry nutrients and oxygen from the lungs to all of the tissues and organs in the body. Additionally, it aids in removing toxins and carbon dioxide. The immune system, lymphatic system, and neurological system are additional body systems that work conjunction with the respiratory system.
Key term: carbon dioxide
chemical compound (CO2 ); colorless gas;
byproduct of human metabolism
Features of the Respiratory System
Oral Cavity
Nose and linked air passages referred to as the nasal cavity and the sinuses
Larynx (a.k.a. “voice box”)
The trachea or, “windpipe”
Bronchi
Smaller tubes called bronchioles that branch from the bronchial tubes
Alveoli (tiny air sacs at the end of bronchioles)
Pleura (both lungs are surrounded by this membrane with two layers)
These features form the airway that brings the oxygen-rich air from the environment to the alveoli in the lungs. The airway also provides an exit for carbon dioxide from the body.
Core Functions of the Respiratory System
Breathing
Gas Exchange
The respiratory system is responsible for introducing oxygen into the body, which is crucial for the normal operation of cells and organs.
Carbon dioxide removal; the respiratory system expels carbon dioxide, which is a byproduct of cellular metabolism.
The body's acid-base balance is assisted by the respiratory system through the removal of extra hydrogen ions and the maintenance of optimal pH levels.
Speech and phonation; the respiratory system controls airflow through the vocal cords to create sound and speech.
Safety; the respiratory system safeguards the body by filtering the air inhaled, removing harmful particles and germs to protect the lungs from pathogens.
Gas Exchange
The alveoli are the site of gas exchange in the lungs.
The alveoli, or tiny air sacs at the end of the bronchioles, are surrounded by a network of capillaries. These capillaries connect to arteries and veins that transport blood throughout the human body.
One artery of note is the pulmonary artery. The pulmonary artery (and its branches) bring blood to the capillaries around the alveoli. The blood they bring is low in oxygen and rich in carbon dioxide.
Remember, the alveoli are the site of gas exchange. This “exchange” occurs as oxygen-depleted blood travels through the pulmonary capillaries that encircle them. The carbon dioxide easily passes from the blood into the alveoli through diffusion. A concentration gradient drives the process.
The body releases the carbon dioxide to the environment through the mouth and nose as it is exhaled. At the same time, oxygen from the air enters the small blood vessels in the lungs and attaches to hemoglobin in the red blood cells.
Key term: diffusion
movement of ions, molecules from an area of higher concentration to an area of lower concentration;
driven by a gradient
Key term: hemoglobin
iron-containing protein of the blood that transports oxygen to the tissues;
vital component of red blood cells
Hemoglobin
The hemoglobin molecule assists in the transport of oxygen throughout the body.
Hemoglobin is a protein containing iron. This molecule is found within the red blood cells (erythrocytes) of vertebrates where it functions to transport oxygen from the lungs to all tissues and organs. Hemoglobin creates a temporary and unstable connection with oxygen, enabling the release of oxygen to the tissues when necessary.
Each hemoglobin molecule contains four heme groups. Heme is made up of a ringlike organic compound with an attached iron atom. The iron atom is what attaches oxygen while the blood moves from the lungs to the tissues. When in this oxygenated form, it appears as oxyhemoglobin and has a bright red color; when in the reduced form, it appears as purplish blue.
Hemoglobin is produced in the bone marrow cells that eventually transform into red blood cells. When red blood cells expire, their hemoglobin is divided: the iron is saved, carried to the bone marrow and reused, making new red blood cells; the rest of the hemoglobin becomes bilirubin, which is released in the bile and causes the yellow-brown color of stool.
Helpful Videos:
Recommended Reading (Optional)
Medical Terminology for Healthcare Professions, Katherine Greene and Andrea Nelson
Read Chapters 11 & 12
