Anatomy - Respiratory system Flashcards
What can respiration mean
Ventilation of the lungs (breathing).
The exchange of gases between air and blood, and between blood tissue and tissue fluid.
The use of oxygen in cellular metabolism (not respiratory system).
What is the respiratory system
The respiratory system is an organ system that rhythmically takes air in and out of the body, thereby supplying the body with oxygen and expelling the carbon dioxide that it generates.
What are the main functions of the respiratory system
- Provide for oxygen and carbon dioxide exchange between the blood and air in the atmosphere.
- It serves for speech and other types of vocalisations such as screaming, laughing or crying.
- It provides the sense of smell, which is important for food selection, and avoiding danger.
- Eliminates CO2, which helps to control the pH of the body fluids.
- Regulation of blood pressure.
- Breathing creates pressure gradients between the thorax and abdomen that promote the flow of lymph and blood.
- Breath-holding helps to expel abdominal contents during urination, defecation and childbirth by creating intra-abdominal pressure. (valsalva manoeuvre).
How does the respiratory system control the pH of body fluids.
Excess of CO2 reacts with water and releases hydrogen ions, therefore if the respiratory system doesn’t keep pace with the rate of COs production, H+ accumulates and the body fluids have abnormally low pH (acidosis), if too much carbon dioxide is being accumulated, the equilibrium shits left, the concentration of H+ ions decreases and we will have an alkalosis.
How does the the respiratory system regulate blood pressure
This is a multifactorial control process, one of the steps , the synthesis of vasoconstrictors in smooth muscle known as angiotensin II, is carried out by lungs and this helps to regulate blood pressure.
Which organs make up the respiratory system
Nose, pharynx, larynx, trachea, bronchi and lungs.
What is the conductive division
It consists of those passages that serve only for airflow, there is no gas exchange, essentially from the nostrils through the major bronchioles.
What is the respiratory division
It consists of the alveoli and other small bronchials, these are responsible for gas exchange.
What is the upper respiratory system
The airway from the nose through the larynx (organs in head and neck)
What is the lower respiratory system
from the trachea through the lungs (respiratory organs of the thorax).
What are the main parts of the nose
Nasal cavity The vestibule Epithelium Conchae Mucus
Nasal cavity
serves as a resonating chamber that amplifies the voice; it divides into 2 nasal fossae by the nasal septum.
The vesitbule
it is made of stratified squamous epithelium like facial skin and contains guard hairs (vibrissae) which blocks insects and debris.
Epithelium
There is olfactory epithelium, found only in the nose, which is specialized in detection pf odours and the cilia doesn’t move.
Then there is respiratory epithelium which is made of pseudo-stratified columnar cells and it lines the nassal fossae folding into the conchae to increase the surface of the epithelium. It has a high degree of blood flow, which allows the warming of air, and therefore, because of Charles law, the expansion of air, helping in the inflation of the lungs during inspiration.
Conchae
superior, middle and inferior trap finer particles in mucus and warm and humidify air.
Mucus
it is made in goblet cells, they trap finer particles and passes to the pharynx to be swallowed.
(it has a protective role)
What is the Pharynx
It is a muscular funnel that joins the nasal cavity to the larynx and is divided into three parts.
What are the main parts of the Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Nasopharynx
receives air and transports it to the next part of the larynx; it receives the eustachian tubes, which connect the middle ear to the nasopharynx and equalise the pressure on either side of tympanic membrane. It also traps larger particles in the pharyngeal tonsils (immune tissue).
Oropharynx
sits posteriorly to he oral cavity and its purpose is to receive good and liquid while eating, and transmit air to and from the laryngopharynx and nasopharynx. In contains the palatine tonsils.
Laryngopharynx
transmit food, liquid and air to the larynx and oesophagus
What is the larynx
also known as the voice box, consists of nine cartilages, ligaments and muscles. ITs functions are to keep food and drinks out of the airway and PHONATION.
It reacts when the swallowing reflex, which is a two part action: larynx rises and tongue pushes epiglottis down to seal off larynx.
Superior to the trachea there is the laryngeal cartilages which add protection to the anterior part of the larynx and offer anchoring for muscles in head and neck.
What is the trachea
The trachea is a large tube with cartilaginous c-shape rings joined by the trachealis muscle; this makes it flexible and allows it to expand and contract during ventilation.
It is lined by respiratory epithelium and the cilia leads the mucus upwards so it can be swallowed when it reaches the larynx.
About lung tissue…
Three lobes on the right separated by the horizontal and oblique fissure and two in the left lung separated by the oblique fissure.
The tubular structures enter the lungs through the hilum; these include blood vessels and the airways. The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart, and the pulmonary arteries which carry deoxygenated blood from the right ventricle to the lungs.
At the hilum the visceral pleura reflects to become the parietal pleura and on the inferior side each lung sits on top of the diaphragm..
What is a fissure
A double layer of pleural lining
What is the Bronchial tree
The trachea divides into 65.000 terminal bronchi. The main bronchus, being the right one more horizontal and dividing into:
three lobar bronchi, while the left one only has two lobar bronchus, segmental bronchus (ventilate bronchopulmonary unit),
bronchiole (less than 1mm in diameter) and lack cartilage but still have cilia and mucus cells (epithelium - ventilate pulmonary lobule).
Terminal bronchiole (less than 0.5mm and have no mucus.
The respiratory bronchioles, the alveoli are 2.000.000 70m2
About alveoli…
They are the most distal part of the respiratory system. It has three main cells.
Squamous alveolar cells.
Great alveolar cells.
Alveolar macrophage.
Squamous alveolar cells
make up the wall of the alveolus, they are flat and very then because gases must pass through it via passive diffusion (just using concentration gradients)
Great alveolar cells
they are inside the alveolus and make the surfactant fluid. This fluid reduces the surface tension so that the alveolus can be easily inflated.
Alveolar macrophage
derived from monocytes (white blood cells) and are part of the body’s immune response.
About the pleura…
It is a serous membrane which cover the lungs and get reflected at the hila to form the visceral and parietal pleura. The space between these pleurae is called the pleural cavity and it’s filled with pleural fluid. It serves to reduce friction, help in ventilation due to low intrapleural pressure, and prevent infection between organs by compartmentalisation.
Pulmonary ventilation
It includes inspiration and expiration and in order for inspiration to happen, a lower intrapulmonary pressure than atmospheric needs to be generated, and viceversa for expiration.
What two types of inspiration is there
Quiet and forced inspiration
How does inspiration happen
The volume of the thoracic cavity is increased, and due to Boyle’s low, pressure descends.
To increase the volume of the thoracic cavity , the ribcage needs to be moved upwards by the muscles in the head and neck.
Intercostal muscles and pectolranis minor contract to follow the first ribs. At the same time, the diaphragm contracts and move the base of the lungs downwards.
Air temperature increases to 37ºC and due to Charles’ low, volume increases.
Which muscles in head and neck move the rib cage upwards
Sternocleidomastoid and scalenes
What happens during quiet inspiration
the diaphragm does most of the work
What two types of expiration is there
quiet and forced expiration
How does expiration happen
The rectus abdomins and the external abdominal oblique contract and pull the lower rib downwards, the intercostal muscles contract and the ribcage moves downwards decreasing the intra-thoracic volume.
What happens in quiet expiration
It is completely passive as the muscles simply recoil.
What is spirometry
The use of a spirometre to measure the volume of air passing as a function of time.
What is the tidal volume (TV)
Amount of air inhaled and exhaled in one cycle during quiet breathing
What value is (TV)
500 mL
What is Inspiratory reserve volume (IRV)
Amount of air in excess of tidal volume that can be inhaled with maximum effort
What value is (IRV)
3.000 mL
What is expiratory reserve volume (ERV)
Amount of air in excess of tidal volume that can be exhaled with maximum effort
What value is (ERV)
1.200 mL
What is residual volume (RV)
Amount of air remaining in the lungs after maximum expiration; The amount that can never voluntary be exhaled.
What value is (RV)
1.300 mL
Vital Capacity (VC)
The amount of air that can be inhaled and then exhaled with maximum effort; the deepest possible breath (VC = ERV + TV + IRV)
What value is (VC)
4,700 mL
What is Inspiratory (IC)
Maximum amount of air that can be inhaled after a normal tidal expiration (IC = TV + IRV)
What value is (IC)
3,500 mL
What is functional residual capacity (FRC)
Amount of air remaining in the lungs after a normal tidal expiration (FRC = RV + ERV)
What value is (FRC)
2,500 mL
Total lung capacity (TLC)
Maximum amount of air the lungs can contain (TLC = RV + VC)
What value is (TLC)
6 L
Where does gas exchange happen
alveoli
Gas exchange
The partial pressure of oxygen in the alveoli is of 104 mmHg and carbon dioxide is 40mmHg. Deoxygenated blood coming from the heart has a low partial pressure of oxygen = 40mmHg and high partial pressure of Carbon dioxide = 46mmHg, so by diffusion oxygen will move from the alveoli to the blood and carbon dioxide will do the opposite.
Oxygenated blood partial pressure goes to to oxygen = 95 mmHg and carbon dioxide down to 40 = mmHg.
In tissue, partial pressures are of oxygen = 40 mmHg and carbon dioxide 46 mmHg, therefore gas exchange occurs again to form deoxygenated blood and the cycle repeats.
What are the gas concentrations of the inspired air
Oxygen = 159 mmHg
Carbon dioxide = 0.3 mmHg
What are the gas concentration of expired air
Oxygen = 116 mmHg
Carbon dioxide = 32 mmHg
How is oxygen carried
Oxygen is carried in a speciaziled molecule called, hemoglobin, because it is not very soluble in water.
- 5% of oxygen is carried in hemoglobin
- 5% of oxygen is carried in water
What can affect the dissociation curve of hemoglobin
Temperature and pH
How is the dissociative curve of hemoglobin affected by heat
Tissue that is more active generates more heat so homoglobin can unload more oxygen in this area ( the curve moves to the right):
How is the dissociative curve of hemoglobin affected by pH
Tissue that is more active will generate more carbon dioxide, therefore generating more H+ and becoming more acetotic, so the curve shifts to the right too.
