Lecture 21: Respiratory System Flashcards Preview

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Flashcards in Lecture 21: Respiratory System Deck (20):

Identify the organs forming the respiratory passegway in descending order until the alveoli are reached

Major organs:
-Nose, nasal cavity, and paransal sinuses
-bronchi and their branches
-lungs and alveoli

Respiratory muscles:
-diaphragm and other muscles that promote ventilation


What does respiration involve?

In the respiratory system:
1. Pulmonary ventilation (breathing): movement of air into and out lungs
In circulatory system:
2. External respiration: O2 and CO2 exchange between the lungs and the blood
3. Transport: O2 and CO2 in the blood
4. Internal respiration: O2 and CO2 exchange between systemic blood vessels and tissues


Be able to label the respiratory system
Slide 5

Do it!!


Describe the anatomy and functions of the nose

Functions: moistens and warms the entering air
-filters and cleans inspired air
-serves as resonating chamber for speech
-houses olfactory receptors

Two regions: external nose and nasal cavity
1. External nose:
-nostrils: bounded laterally by the alae
2. Nasal cavity: in and posterior to the external nose
-divided by middle nasal septum
-posterior nasal apertures (choanae) open into the nasal pharynx
-Roof: ethmoid and sphenoid bones
-floor: hard and soft palates
Be able to label it slide 7


What is the structure and function if the nasal cavity?
Be able to label the diagram on pg 9

Vestibule: nasal cavity superior to the nostrils
-filter coarse particles from inspired air
Olfactory mucosa:
-lines the superior nasal cavity
-contains small receptors (chemoreceptors)
Superior, middle and inferior nasal conchae
-protrude from the lateral walls
-increase mucosal area


What is the function of the nasal mucosa and conchae and paranasal sinuses?

Functions if the nasal mucosa and conchae:
-during inhalation, the conchae and nasal mucosa
-filter, heat, and moisten air
-during exhalation these structures
-reclaim heat and moisture

Paranasal sinuses:
-in frontal, sphenoid, ethmoid and maxillary bones
-lighten the skull and help to warm and moisten the air


What is the structure and function of the pharynx?

Muscular tube that connects to the
-nasal cavity and mouth superiorly
-larynx and esophagus inferiorly
-from the base of the skull to the level of 6th cervical vertebrae


Nasopharynx structure and function:
View side 11 for picture

-air passageway posterior to the nasal cavity
-soft palate and uvula close nasopharynx during swallowing

Pharyngeal tonsil (adenoids) on posterior wall
Pharyngotympanic (auditory) tubes open into lateral walls


Oropharynx structure and function?

-passageway for food and air from the level if the soft palate to the epiglottis
-palatine tonsils in the lateral walks of fauces (arches)
-lingual tonsil on the posterior surface of the tongue


Laryngopharynx structure and function

-Passageway for food and air
-Posterior to the upright epiglottis
-extends to the larynx, where it is also continuous with the esophagus


Larynx structure and function:
What are the cartilages of the larynx

Continuous with the trachea
1-provides a patent airway
2-routes air and food into proper channels
3-voice production
Cartilages of the larynx:
-thyroid cartilage with laryngeal prominence (Adams apple)
-ring shaped cricoid cartilage
-epiglottis: elastic cartilage; covers the laryngeal inlet during swallowing

Vocal ligaments contain elastic fibres, form core of vocal cords
-opening between them is the glottis
-folds vibrate to produce sound as air rushes up from lungs
Voice production:
-speech: intermittent release of expired air while opening and closing the glottis
-pitch is determined by the length and tension of the vocal cords
-loudness depends on force of air
-chambers of pharynx, oral, nasal, and sinus cavities amplify and enhance sound quality
Vocal folds may act as a sphincter to prevent air passage
Eg: valsalvas maneuver
-glottis closes to prevent exhalation
-abdominal muscles contracts
-intra-abdominal pressure rises
-helps to empty the rectum or stabilise the trunk during heavy lifting


How is our voice created?

Voice production:
-speech: intermittent release of expired air while opening and closing the glottis
-pitch is determined by the length and tension of the vocal cords
-loudness depends on force of air
-chambers of pharynx, oral, nasal, and sinus cavities amplify and enhance sound quality


Trachea structure and function

Windpipe: from the larynx into the mediastinum
-last tracheal
-the point were trachea branches into 2 bronchi
Wall composed of 3 layers
1. Mucosa: ciliated epithelium with goblet cells
2. Submucosa: connective tissue with seromucous glands
3. Adventitia: outermost layer made of connective tissue


Brachial tree (branching) describe how the two branches of bronchi form and what they form into.
Also what are the changes that occur in structure as you move down

Trachea-> right and left main (primary) bronchi
-each main bronchus enters the hilum of one lung
-right main bronchus is wider, shorter, and more vertical than the left
-each main bronchus branches unto lobar (secondary) bronchi (three right, 2 left)
-each lobar bronchus supplies one lobe
-each lobar bronchus branches into segmental (tertiary) bronchi
-bronchioles are less than 1mm in diameter
Change that occur:
From bronchi-> bronchioles, structural changes occur
-cartilage in bronchi and cartilage is absent from bronchioles
-cilia and goblet cells become sparse
-relative amount of smooth muscle increases


Respiratory zone:

Respiratory bronchioles, alveolar ductsm alveolar sacs (clusters of alveoli)
-walls are single layer squamous epithelium
-surrounded by fine elastic fibres
-house alveolar macrophages that keep alveolar surfaces sterile



Occupy all of the thoracic cavity except the mediastinum
Root: site of vascular and bronchial attachments
Costal surface: anterior, lateral, and posterior surfaces
Apex: superior tip
Base: inferior surface that rest in the diaphragm
Hilum: on mediastinal surface; site for attachment if blood vessels, bronchi, lymphatic vessels, and nerves
Left lung is smaller, separated into 2 lobes by an oblique fissure
Right lung has 3 lobes separated by oblique and horizontal fissures
-lobules are the smallest subdivisions; serves by bronchioles and their branches


Blood supply to the lungs

Pulmonary circulation (low pressure, high volume)
-pulmonary arteries- deliver systemic venous blood
(Feed Into the pulmonary capillary networks)
Pulmonary veins- carry oxygenated blood from respiratory zones to the heart

Systemic circulation: (high pressure, low volume)
-bronchial arteries provide oxygenated blood to lung tissue
-arise from aorta and net the lungs at the hilum
-supply all lung tissue except alveoli
-bronchial veins- anastomoses with pulmonary veins


What is the pleurae, what is it for?

-thin, double layered serosa
-parietal pleura on thoracic wall and superior face of diaphragm
-visceral pleura on external lung surface
-pleural fluid fills the slitlike pleural cavity
-provides lubrication and surface tension


Mechanics of breathing. Pulmonary ventilation consists of 2 phases, what are they?

1. Inspiration: gas flows into the lungs
An active process:
-inspiratory muscles contract
-thoracic volume increases
-lungs are stretched and intrapulmonary volume increases
2. Expiration: gas exits the lungs
-inspiratory muscles relax
-thoracic cavity volume decreases
-elastic lungs recoil and intrapulmonary volume decreases


Influence if higher brain centres on breathing

Rising CO2 levels are the most powerful respiratory stimulant
-hypothalamic controls act through the limit system to modify rate and depth of respiration
Eg: breath holding that occurs in anger or gasping with pain
-a rise in body temperature act to increase respiratory rate
-cortical controls are direct signals from the cerebral motor cortex that bypass medullary controls
Eg voluntary breath holding