CH22: RESPIRATORY SYSTEM INFECTIONS

what is the main function of the respiratory system

the respiratory system allows the body to take in oxygen and remove carbon dioxide through breathing

what are the two main parts of the respiratory system

the upper respiratory tract and the lower respiratory tract

what are the structures of the upper respiratory tract

nasal cavity, pharynx, and larynx

what are the structures of the lower respiratory tract

trachea, bronchi, bronchioles, and lung

what is the nasal cavity

the nasal cavity is the large air-filled space and behind the nose that filters, warms, and moistens incoming air

what are the frontal sinus and sphenoid sinus

they are hollow air-filled spaces in the skull that help lighten the head and produce mucus to trap particles

what are the nares

the nares are the nostrils-openings that allow air to enter the nasal cavity

what is the nasolacrimal duct

its the small tube that drains tears from the eyes into the nasal cavity, which is why your nose runs when you cry

how is the ear connected to the upper tube respiratory tract

through the eustachian tube (auditory tube), which connects the middle ear to the nasopharynx

what does the eustachian tube do

it helps equalize air pressure on both sides of the eardrum

what are the three main parts of the ear

the external ear, middle ear, and inner ear

what structures are found in the external ear

the ear canal and the tympanic membrane (eardrum)

what is the tympanic membrane

its the eardrum that vibrates when sound waves hit it, starting the hearing process

what is the tympanic cavity

the middle ear chamber that contains small bones which help transmit sound vibrations

what is the cochlea

a spiral-shaped structure in the inner ear that helps with hearing

what is the pharynx

the pharynx (throat) is a muscular tube that connects the nasal cavity and mouth to the larynx and esophagus. it serves both respiratory and digestive functions.

what are the three parts of the pharynx

the nasopharynx, oropharynx, and laryngopharynx

what is the nasopharynx

te upper part of the pharynx located behind the nasal cavity; it connects to the Eustachian tube

what is the oropharynx

the middle part of the pharynx located behind the oral cavity (mouth)

what is the laryngopharynx

the lower part of the pharynx that connects to the larynx and esophagus

what are fauces

the opening at the back of the mouth leading into the oropharynx

what are the tonsils, and where are they located

tonsils are lymphatic tissues that help defend against infection

-pharyngeal tonsil - in the nasopharynx (also called adenoids)

-palatine tonsil - on each side of the oropharynx

-lingual tonsil - at the base of the tongue

what is the larynx

the larynx, or voice box, is the structure that contains the vocal cords and connects the pharynx to the trachea

what are the vocal folds (vocal cords)

they are tissues in the larynx that vibrate to produce sound when air passes through

what is the epiglottis

the epiglottis is a flap of tissue that closes over the trachea during swallowing to prevent food from entering the airway

what is the thyroid gland

its an endocrine gland located near the layrnx that produces hormones controlling metabolism

what is the trachea

the trachea, or windpine, is a tube that carries air from the layrnx to the lungs

what does the trachea conenct to

it connects the layrnx to the bronchi to the bronchi of the lungs

what connects the ear to the nasopharynx

the eustachian tube (auditory tube)

what is the pathway of air through the upper respiratory tract

air enters through the nares → passes through the nasal cavity → nasopharynx → oropharynx → laryngopharynx → larynx → trachea.

which part of the pharynx is shared by both the respiratory and digestive systems

the oropharynx and laryngopharynx

what is the name of the muscle located beneath the lungs that contracts to aid in breathing

the muscle located beneath the lungs that contracts to aid in breathing is the diaphragm

what are the first major branches off the trachea that enter the lungs

the first major branches off the trachea that enter the lungs are the primary bronchi

what is the order of the progressively smaller air passages branching off the primary bronchus

the air passages progressively branch from the primary bronchus into the secondary bronchus, then the tertiary bronchus, then the bronchiole, and finally the terminal bronchiole

what structure is a cluster of alveoli at the very end of the respiratory passage

a cluster of alveoli at the very end of the respiratory passage is called an alveolar sac

what are the tiny air sacs within the lungs where gas exchange occurs

the tiny air sacs within the lungs where gas exchange occurs are the alveoli

what small blood vessels surround the alveoli

small blood vessels called capillaries surround the alveoli to facilitate gas exchange with the bloodstream

what is the function of the pulmonary artery in relation to the alveoli

the pulmonary artery carries deoxygenated blood (low in O2) to the capillaries surrounding the alveoli

what is the function of the pulmonary vein in relation to the alveoli

the pulmonary vein carries oxygenated blood (rich in O2) away from the capillaries surrounding the alveoli and back to the heart

how does gas exchange happen between the alveolus and the capillary

oxygen moves from the air inside the alveolus into the capillary, while carbon dioxide moves from the blood in the capillary into the alveolus to be exhaled

what type of epithelium makes up the surface layer of this membrane

the surface layer of this membrane is composed of pseudostratified columnar epithelium

what are the hair-like projections on the surface of the cells in the lumen

the hair-like projections on the surface of the cells that face the lumen of the trachea are called cilia

what is the name of the central space or channel within the trachea

the central space or channel within the trachea is called the lumen of trachea

what specialized cells are responsible for producing mucus in the respiratory lining

the specialized cells responsible for producing mucus are the goblet cells

what type of gland is found deeper in the tissue beneath the respiratory epithelium

a seromucous gland in submucosa is found deeper in the tissue, which secretes mucus and watery fluid

what role does mucus play in the respiratory system

mucus traps dust, pathogens, and other particles in the air, preventing them from reaching the lungs and keeping the respiratory system clean

what is the ciliary escalator and how does it defend the respiratory system

the ciliary escalator is made of tiny hair-like structures called cilia they move mucus upward toward the throat, where it can be swallowed or expelled, removing trapped pathogens and debris

what is the function of MALT (mucosa-associated lymphoid tissue) in the respiratory system

MALT contains immune cells that constantly monitor the respiratory tract for harmful pathogens and initate immune responses when needed

how does IgA protect the respiratory system

IgA is an antibody found in mucosal secretions that binds to pathogens, neutralizing them and preventing them from attaching to and infecting respiratory cells

what is the role of lysozyme in respiratory defense

lysozyme is an enzyme in mucus and other secretions that destroys bacterial cells walls, helping to kill bacteria before they can cause infection

how does surfactant contribute to respiratory defense

surfactant reduces surface tension in the alveoli, preventing their collapse and also contains proteins that can destroy bacteria and viruses, aiding in immune defense

what are antimicrobial peptides, such as defensis, and what do they do in the respiratory system

antimicrobial peptides like defensins are small proteins that can directly kill bacteria, fungi, and viruses, providing a chemical defense in the respiratory tract

what role do alveolar macrophages play in defending the lungs

alveolar macrophages are immune cells in the alveoli that engulf and destroy pathogens, dust, and debris, helping to keep the lower respiratory tract clean and safe from infection

how do mucus and cilia work through to protect the respiratory system

mucus traps particles and pathogens, and the cilia move the mucus upward toward the throat. this coordinated action, called the mucociliary escalator, prevents pathogens from reaching the lungs

what types of pathogens are targeted by lysozyme

lysozyme mainly targets bacteria by breaking down their cell walls, particularly gram-positive bacteria, helping prevent respiriatroy infections

how does IgA prevent infections in the respiratory system

IgA binds to bacteria and viruses in the mucous lining, blocking their attachment to epithelial cells, which stops them from colonizing and causing infection

why is the mucociliary escalator important for preventing lower respiratory infections

by constantly moving mucus with trapped particles upward, the mucociliary escalator prevents bacteria and viruses from reaching the delicate alveoli, reducing the risk of pneumonia and bronchitis

can the defenses of the respiratory system fail

yes, defenses can fail due to excessive pathogens, smoking, pollution, genetic conditions, or immune suppression, which can lead to infections like bronchitis, pneumonia, or influenza

how do respiratory defenses work together as a system

the respiratory system combines physical barriers (mucus, cilia), chemical defenses (lysozyme, defensins, surfactant), and immune surveillance (MALT, IgA, alveolar macrophages) to create a layered defense that protects the body from airborne pathogens

what is the primary type of response the body has during a respiratory infection

the body produces an acute inflammatory response during a respiratory infection

why do respiratory infections often cause inflammation

respiratory infections cause inflammation because the immune system sends immune cells and chemicals to fight pathogens, which leads to redness, swelling, heat, and pain

how are respiratory infections commonly named

respiratory infections are commonly named based on their location and usually end with the suffix -itis, meaning "inflammation of"

what are some examples of respiratory infections that end in -itis

examples include rhinitis (nose), sinusitis (sinuses), pharyngitis (throat), laryngitis (voice box), otitis (ear), and bronchitis (bronchi)

what happens in pneumonia

in pneumonia, the alveoli become inflamed and fill with pus, bacteria, fluid, and immune cells

how does pneumonia affect gas exchange in the lungs

pneumonia reduces gas exchange because fluid-filled alveoli cannot properly transfer oxygen and carbon dioxide

what fills the alveoli during pneumonia

during pneumonia, the alveoli fill with pus, fluid, blood cells, and inflammatory debris

why does an X-ray of pneumonia appear cloudy or white

a pneumonia X-ray appears cloudy or white because fluid and inflammation make the lung tissue more dense than normal air-filled lungs

what does a normal lung X-ray look like

a normal lung X-ray appears dark because the lungs are filled with air, which does not block the X-ray beam

what symptoms can occur when the alveoli are filled with fluid

symptoms include shortness of breath, difficulty breathing, chest pain, coughing, and decreased oxygen levels

why does inflammation of the alveoli impair breathing

inflammation thickens the alveolar walls and fills the air spaces, making it harder for oxygen to pass into the bloodstream

what does inflammation in the respiratory tract try to accomplish

inflammation tries to destroy pathogens, remove damaged tissue, and begin the healing process

what is the specific pathogen that causes Streptococcal pharyngitis and scarlet fever

the pathogen that causes Streptococcal pharyngitis and scarlet fever is Streptococcus pyogenes

what is another common name for Streptococcal pharyngitis

another common name for Streptococcal pharyngitis is strep throat

what are the key biochemical characteristics of Streptococcus pyogenes that help distinguish it in a lab

Streptococcus pyogenes is gram-positive, catalase-negative, and exhibits beta-hemolytic activity

how is a Streptococcal infection, like Strep throat, primarily transmitted from person to persn

Streptococcal infections are primarily transmitted through direct contact, such as inhaling respiratory droplets or coming into contact with a fresh lesion from an infected person

what is the recommended treatment for Streptococcal infections

Streptococcal infections are treated with antibiotics

what is the primary reason it is crucial to aggressively treat Strep throat with antibiotics

aggressively treating Strep throat with antibiotics is crucial because, if left untreated, it can lead to serious complications, such as Rheumatic fever or Post-Streptococcal Glomerulonephritis

what causes the petechiae (tiny red spots) seen on the plate or throat in some cases of Strep throat

the petechiae are caused by microcapillary hemorrhages often due to the erythogenic toxin produced by the bacteria

what are some of the most common signs and symptoms that are usually present with strep throat

common signs and symptoms include a sore throat that starts quickly, pain when swallowing, fever, red and swollen tonsils (sometimes with pus), and swollen lymph nodes in the front of the neck

what specific visible signs might be seen on the back of the throat/palate in a case of Strep throat

visible signs can include bright red arches of inflammation (pharyngitis) and sometimes tiny red spots (petechiae) on the roof of the mouth

how does scarlet fever present differently from Strep throat

scarlet fever is a systemic infection that presents with all the signs of Strep throat plus a rash on the skin and a strawberry tongue

what common cold symptoms are typically NOT associated with a Strep throat infection

symptoms typically not associated with Strep throat include a cough, runny nose, and hoarseness

what is considered the gold standard lab method for confirming pharyngitis due to S. pyogenes

a throat culture remains the gold standard for confirming pharyngitis due to S. pyogenes

what are some other diagnostic tests used to identify a Streptococcal infection

other diagnostic tests include direct culturing of a throat swab, a rapid Strep A immunoassay (Rapid Strep Test), or an antigen test

what is the advantage of using a Rapid Strep A Test

the Rapid Strep A Test allows for a quick detection of the S. pyogenes antigen right in the clinic or doctor's office

what is the term for a disease that develops from a severe complication following an S. pyogenes infection

a severe complication that develops following an S. pyogenes infection is called a sequela (plural: sequelae)

what is one of the major sequelae of untreated S. pyogenes pharyngitis (strep throat) in children

one major sequela is acute rheumatic fever

which major body systems are affected by acute rheumatic fever

the most dangerous consequence is inflammation of the heart and blood vessels, which often leads to extensive heart valve damage

what is the second major sequela of an S. pyogenes infection listed

Acute glomerulonephritis targets the kidneys

what are the glomeruli that are affected in Acute glomerulonephritis

the glomeruli are the tiny filters in the kidneys that become inflamed during Acute glomerulonephritis

why is prompt antibiotic treatment for strep throat essential in preventing these sequelae

prompt antibiotic treatment is essential because it eliminates the bacteria it eliminates the bacteria, which prevents the immune system's reaction (likely an autoimmune response) that cause the inflammation and damage associated with Acute Rheumatic Fever and Acute Glomerulonephritis

what is the condition known as AOM

the condition is Acute Otitis Media (AOM)

list the three most frequent bacterial pathogens responsible for causing Acute Otitis Media

the three most frequent bacterial pathogens are Haemophilus influenza, Streptococcus pneumoniae, and Moraxella catarrhalis

what are the most common patient complaints and clinical findings associated with acute Otitis Media

the most common complaints are a painful earache and often collection of fluid (effusion) in the middle ear. patients may also experience general symptoms like fever, nausea, vomiting, and diarrhea

explain the usual process by which AOM develops in the ear

the infection commonly begins as a secondary infection where bacteria that originated in the respiratory tract travel and become sealed off inside the Eustachian tube, leading to inflammation and infection of the middle ear space

regarding the anatomy, where does the inflammatory fluid originate, and which structure's blockage cause the fluid to accumulate in AOM

the inflammatory fluid originates from secretions of the upper respiratory pathways. the fluid accumulates because the Eustachian tube becomes inflamed and swollen, which prevents the built-up exudate from draining properly

what two classes of antibiotic medications are used to treat AOM, and name a common drug for each class

the two major classes of antimicrobial drugs for treatment are Cephalosporins (e.g., Ceftriaxone or Cefdinir) and Fluoroquinolones (e.g., Ciprofloxacin or Levofloxacin)

how is the diagnosis of Acute Otitis Media typically confirmed

the diagnosis is typically confirmed by a clinician observing the patient's symptoms and visually examining the eardrum to check for signs of inflammation and fluid

is there a widespread preventative inoculation available specifically for Acute Otitis Media

no specific vaccine is currently available to prevent the overall occurrence of Acute Otitis Media

describe the healthy appearance of the eardrum and the bones visible behind it during a routine examination

a healthy eardrum (tympanic membrane) appears intact and transparent. this transparency allows the clinician to see the outlines of the middle ear bones, specifically the malleus and incus, clearly positioned behind it