9: The Respiratory System Flashcards
What is cellular respiration?
Cellular respiration is a complete process which breaks down glucose into carbon dioxide and water, with a release of energy that is trapped in ATP, which fuels the cellular process
What is respiration?
The processes that carry O2 to the cells and CO2 away from the cells are collectively called respiration. Respiration is made up of four components:
- Ventilation
- Gas exchange x2
- Transport
What is ventilation in respiration?
Ventilation is breathing. It is the movement of air containing O2 into the lungs removing CO2 from the lungs and into the atmosphere
The structures that contribute to ventilation include: passage ways to the lungs and the muscular and skeletal components of the thorax
What is transport in respiration?
In respiration, oxygen and carbon dioxide are transported in the blood
What is gas exchange in respiration?
In respiration, gas is exchanged:
- In the lungs between the air and the blood. O2 diffuses into the blood and CO2 diffuses out of the blood
- Between blood and tissues
What is the respiratory system?
The respiratory system describes the structures that bring about respiration as a whole
What are the roles of the respiratory system?
The roles of the respiratory system include:
- Respiration
- Regulation of blood pH
- Production of chemical mediators
- Voice production
- Olfactation
- Protection
How does the respiratory system regulate blood pH levels?
The respiratory system can regulate blood pH levels by changing CO2 levels
How does the respiratory system produce chemical mediators?
The lungs produce ACE which is important in regulating blood pressure
How does the respiratory system produce voice?
The respiratory system makes speech production possible by moving air past the vocal folds it makes sound and speech
How does the respiratory system play a role in olfactation?
Smell sensation occurs when airborne molecules are drawn into the nasal cavity through inhaling
How does the respiratory system offer protection to the body?
The respiratory system provides protection against microorganisms by preventing them from entering the body and removing them from respiratory surfaces
What is the thoracic cavity made up of?
The thoracic cavity contains the lungs and is made up of:
- Thoracic vertebrae
- Ribs
- Costal cartilages
- Sternum
- Associated muscles
What drives the movement of gases in to and out of the lungs?
Changes in the arrangement of the five components of the thoracic cavity drives the movement of gases in and out of the lungs
How does the thoracic cavity move air into the lungs?
To get air to move into the lungs, the pressure inside the thora must be less than the atmospheric pressure, so the air moves down the concentration gradient
The thoracic pressure is reduced by increasing the chest volume
How does the thoracic cavity get air to move out of the lungs?
To get air to move out of the lungs, the pressure inside the thora must be more than the atmospheric pressure, so the air moves down the concentration gradient
The thoracic pressure is increased by reducing the chest volume
What are the structures that make up the passageways where gasses pass?
The structures that make up the passageways along which the gasses pass are:
- External nose
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs
What is the conducting zone?
The conducting zone is the components from the external nose to the bronchioles
What is the role of the conducting zone?
The conducting zone is where air movement, cleaning, warming and humidification takes place
What is the respiratory zone?
The respiratory zone is the lungs
What is the role of the respiratory zone?
The respiratory zone is where the gas exchange between air and blood takes place
What is the external nose made up of?
The external nose is mainly composed of hyaline cartilage. The bridge of the nose consists of nasa bones and extensions of the frontal and maxillary bones
What is the nasal cavity?
The nasal cavity extends from the nostrils, to the choane, where the pharynx begins
What are the roles of the nasal cavity?
The nasal cavity has a number off important roles:
- Passageway for air
- Cleans the air
- Humidifies and warms the air
- Contains the olfactory epithelium
- Helps determine voice
How does the nasal cavity clean the air?
The nasal cavity cleans the air by the hairs lining the vestibule, which traps large particles
How does the nasal cavity help determine voice?
The nasal cavity determines voice b acting as a resonating chamber
What is the conchae made up of?
The conchae is made up of three bony ridges, beneath each ridge is a passageway called a meatus
In the superior and middle meatus we see openings from the paranasal sinuses. In the inferior meatus is an opening to the nasalocrimal duct
What is the role of the conchae?
The conchae modify the shape of the lateral nasal cavity wall
What is the role of the nasalocriminal duct?
The nasalocriminal duct drains tears from the eyes
What is the nasal cartilage made up of?
The nasal cartilage includes the nasal septum. The anterior part of the septum is cartilage and the posterior part is formed from the vomer bone inferiorly and the perpendicular part of the ethmoid bone superiorly
What is the role of the nasal septum?
The nasal septum separates the cavity into left and right sections
What is the hard palate made up of?
The hard palate is formed by the palatine process of the maxillary bones and the palatine bones. It forms the floor of the nasal cavity
What is the role of the hard palate?
The hard palate forms the floor of the nasal cavity and separates it from the oral cavity
What is the pharynx?
The pharynx is the term for the common opening for the digestive and respiratory systems
It is made up of three parts
What are the three regions of the pharynx?
The three regions of the pharynx are:
- The nasopharynx
- The oropharynx
- The laryngopharynx
Where is the nasopharynx found?
The nasopharynx is located posterior to the conchae and superior to the soft palate
What is the soft palate?
The soft palate is an incomplete muscle and connective tissue partition that separates the nasopharynx from the oropharynx
What is the role of the sot palate?
The soft palate separates the nasopharynx from the oropharynx
The soft palate prevents food from entering the nasopharynx and nasal cavity
Where is the uvula found?
The uvula is the posterior extension of the soft palate
Where is the pharyngeal tonsil found?
The pharyngeal tonsil is found on the posterior surface of the nasopharynx
What is the role of the pharyngeal tonsil?
The pharyngeal tonsil helps prevent infection
Where are the Eustachian tubes found?
The Eustachian tubes open from the middle ear cavities into the nasopharynx
Where is the oropharynx found?
The oropharynx extends from the soft palate to the epiglottis
Where are the palatine and lingual tonsils found?
The palatine and lingual tonsils are found near the fauces
Where is the oral cavity found?
The oral cavity opens into the oropharynx and the fauces
Where is the laryngopharynx found?
The laryngopharynx extends from the tip of the epiglottis to the oesophagus, passing posteriorly to the larynx
What is the role of the laryngopharynx?
Food and drink pass through the laryngopharynx and into the oesophagus
Where is the larynx found?
The larynx extends from the base of the tongue to the trachea. It is connected supriorly to the hyoid bone by muscles and membranes
What are membranes?
Membranes are sheets of connective tissue
What is the role of the larynx?
The larynx is the conducting passageway for air from the pharynx to the trachea
What is the larynx made up of?
The larynx is made up of nine cartilages held together with muscles and ligaments. There are three sets of paired cartilages and three unpaired cartilages
What are the three unpaired cartilages of the larynx?
The three unpaired cartilages that contribute to the larynx are:
- The thyroid cartilage
- Cricoid cartilage
- Epiglottis
What is the thyroid cartilage?
The thyroid cartilage is an unpaired cartilage of the larynx
It is the largest of the cartilages and forms the Adam’s apple
What is the cricoid cartilage?
The cricoid cartilage is an unpaired cartilage of the larynx
It is the most inferior of the cartilages, and forms the base of the larynx, which the other cartilages sit upon
What is the epiglottis?
The epiglottis is is an unpaired cartilage of the larynx
It is attached to the thyroid cartilage, and projects superiorly as a free flap towards the tongue. It differs from the other eight cartilages because it is made of elastic cartilage, rather than hyaline cartilage
What are the three pairs of cartilages that form the larynx?
The three paired cartilages that form the larynx are:
- The arytenoid cartilages
- The corniculate cartilages
- The cuneiform cartilages
What are the arytenoid cartilages?
The arytenoid cartilages are a set of the paired cartilages of the larynx
They articulate with the posterior superior border of the cricoid cartilage
What are the corniculate cartilages?
The corniculate cartilages are a set of the paired cartilages of the larynx
They attach to the superior tips of the arytenoids
What are the cuneiform cartilages?
The cuneiform cartilages are a set of the paired cartilages of the larynx
They sit within a mucus membrane anterior to the corniculate cartilages
What are the false vocal cords?
The false vocal folds are also called the vestibular folds. They are a mucus membrane that covers the inferior ligament that connects the arytenoid cartilages to the posterior surface of the thyroid cartilage
What is the glottis?
The glottis is the vocal folds and the opening between them
What covers the vestibule and vocal cords?
The vestibule ad vocal cords are covered with stratified squamous epithelium
What covers the larynx?
The remainder of the larynx is covered with pseudostratified ciliated columnar epithelium
What are the roles of the larynx?
The larynx has four important roles:
- Passageway for air
- Prevents food entering respiratory tract, and regulates air movement within
- Sound production
- Traps debris
How does the larynx provide a passageway for air?
The thyroid and cricoid cartilages in the larynx provide a passageway for air
How does the larynx prevent food entering the respiratory tract?
The larynx prevent food from entering the lower respiratory tract by using the epiglottis to tip over and cover the opening to the larynx. The vestibular and vocal cords come together medically to close the larynx and prevent food entry
How does the larynx control air flow?
The larynx can control air flow by using the epiglottis to tip over and cover the opening to the larynx. The vestibular and vocal cords can come together medically to close the larynx and prevent movement of air into and out of the larynx
How does the larynx produce sound?
The vocal folds are found in the larynx and are the primary source of sound production. Air passing over the cords causes them to vibrate and produce sound
How does the larynx control sound?
Sound is produced by air passing over the vocal folds in the larynx
The larynx can control the air flow in and out, meaning it can control the air passing over the vocal folds
The larynx can also control sound production by moving the arytenoid cartilages to change the position and length of the vocal folds, therefore the passage of air and therefore the sound produced
How does the larynx trap debris in the air?
The larynx has a pseudostratified ciliated columnar epithelium lining it, which produces mucus to trap debris in the air
What does the larynx do with trapped debris?
Debris trapped by mucus int he larynx is moved up to the pharynx by the cilia. The mucus is then swallowed in the pharynx
What is the structure of the trachea?
The trachea is a 10-12cm tube, made up of dense regular connective tissue and smooth muscle. It is lined with pseudostratified ciliated columnar epithelium and many goblet cells
It is reinforced anteriorly and laterally by 15-20 C shaped cartilages.
Instead of cartilage, the posterior has an elastic ligament and bundles of smooth muscle to reinforce
What are the trachealis?
The trachealis are the elastic ligament and bundles of smooth muscle that reinforce the posterior trachea
How does the trachea control its diameter?
The trachea has a resting internal diameter of 12mm
Contraction of the smooth muscle can reduce the diameter of the trachea. Reduced diameter causes air to move more rapidly
Why does the trachea change its diameter?
The trachea changes its diameter to control the speed and pressure of airflow. This is helpful in actions like coughing, where the reduced diameter causes air to move more rapidly, and help rid the tube of mucus and foreign objects
What do goblet cells do?
Goblet cells secrete mucus
What is the role of mucus?
Mucus helps to trap debris in the ir and move it up to the pharynx where it is swallowed
Where is the Ariana found?
The Ariana is a ridge formed from the most inferior cartilage. This is where the branching takes place at the level of the 5th thoracic vertebra, where the trachea divides down into two main bronchi
What is the role of the Ariana?
The Ariana is extremely sensitive to foreign bodies and anything contacting it will initiate a powerful coughing reflex
Describe the branching in the bronchi:
Approximately 16 sets of branching takes place from the trachea to the terminal bronchioles
7 branchings then take place from the terminal bronchioles to the alveolar ducts, making a total of 23 branchIngs
The main bronchi divide into lobar bronchi: two in the left lung and three in the right
The lobar bronchi continue to divide into the segmental bronchi
The segmental bronchi divides into the bronchioles
The bronchioles sub-divide to form terminal bronchioles
The terminal bronchioles further divide into respiratory bronchioles
The respiratory bronchioles divide into alveolar ducts
Describe how the structures change with branching of the bronchi:
There are approximately 16 sets of branching from the trachea to the terminal bronchioles
As the branches become smaller, the cartilages disappear and the walls have more smooth muscle
What is the order of branching of the bronchi?
The bronchi divides in the following way:
- Main bronchi
- Lobar bronchi
- Segmental bronchi
- Bronchioles
- Terminal bronchioles
- Respiratory bronchioles
- Alveolar ducts
How do the bronchi change the volume of air flow?
The state of contraction of smooth muscle in the bronchi and bronchioles can change the diameter of the passageway, and therefore the volume of air passing through
Why do the bronchi subdivide so much?
There are 23 branchings from the trachea to the alveolar ducts. This results in a huge surface area, where gas exchange can take place. An increased surface area increases the rate of the gas exchange
What are alveoli?
Each alveolus is a small air filled chamber
What is the role of alveoli?
Alveoli is where gas exchange takes place between air and blood
What is the structure of alveoli?
The thin connective tissue surrounding the alveoli contains elastic fibres that allow the alveoli to explanad on inspiration and air to enter
The elastic fibres recoil to force air out on expiration
Alveoli are made up of two different types of cell: Type I and Type II
What are Type I cells in alveoli?
Type I pneumocytes are thin, simple squamous epithelial tissues and make up 90% of the alveolus
What is the role of Type I cells in alveoli?
Type I cells are where most gas exchange takes place across these cells
What are Type II cells in alveoli?
Type II pneumocytes are cuboidal shaped cells
What is the role of Type II cells in alveoli?
Type II cells secrete surfactant. The surfactant makes it easier for the alveoli to expand and open during inspiration
What is the thoracic cavity?
The wall of the thorax creates a cavity called the thoracic cavity, within which are the lungs and heart
What is the mediastinum?
The mediastinum is a space behind the sternum that separates the left and right lungs
The heart sits within the mediastinum
What separates the thoracic cavity from the abdominal cavity?
The thoracic cavity is separated from the abdominal cavity inferiorly by the diaphragm
What are the two processes of breathing?
Breathing can be described as two processes:
- Inspiration
- Expiration
What is inspiration?
Inspiration is taking in air and filling the lungs
What is expiration?
Expiration is when air exits and empties the lungs
Which muscles contribute to te processes of inspiration?
Many muscles contribute to the processes of inspiration, but the muscles that contribute depends on the kind of breathing that is taking place
Which muscles contribute to normal or Uriel inspiration?
Normal or Uriel breathing will usually only involve the diaphragm
What is the role of the diaphragm in the respiratory system?
The diaphragm is a major contributor to breathing, because it drives both inspiration and expiration
75% of the change in lung volume is as a result of the contraction and relaxation of the diaphragm
What muscles are involved in inspiration when there is a large demand for oxygen?
On exercise where demand for oxygen rises, the movement of the diaphragm can increase. While the demand increases, the accessory muscles are brought into play
What is the roles of the accessory muscles in respiration?
The accessory muscles are brought into play in inspiration where there is a high demand for oxygen
The accessory muscles bring about forced inspiration and expiration, that changes the positioning of the ribs and sternum, increasing the volume of the thorax
What is the role of the ribs in respiration?
At rest, the ribs are directing slightly downwards. During inspiration, muscles attached to the ribs cause them to move upwards and forwards
The movement of thee ribs and sternum together cause an increase in thoracic volume
What is the role of the external intercostals in inspiration?
The external intercostals are the most important accessory muscle in inspiration. They cause the rib cage to elevate and the sternum to move forwards. This increases the chest volume
The external intercostals play a major role in speech generation
What are the minor contributors to increasing chest volume?
The external intercostals are the main additional contributor to increasing chest volume. Any other muscle that attaches to the ribs and sternum has the capacity to contribute
These minor contributors are:
- Pectoralis major
- Lecatores costarum
- Serratus posterior superior
- Scalenes
What are the major contributing uncles to expiration?
As with inspiration, the major contributor to expiration is the diaphragm
Other muscles contribute, including:
- The internal intercostals
- Transverse thoracis
- Abdominal muscles
How does the diaphragm change the volume of the lungs?
Relaxation of the diaphragm sees the dome shape restored and a decrease in lung volume
How do the other contributors play a role in expiration?
Aside from the diaphragm, the three other contributors cause the ribs and sternum to move back downwards and inwards
