Respiratory System Flashcards
What is the function of the respiratory system?
Provides oxygen to the body, disposes of carbon dioxide and helps regulate blood pH.
Where does gas exchange occur?
Respiratory membrane - In the alveoli in the lungs, and at capillary beds around the body.
What is the normal breathing rate for adults?
12-20 breaths per minute. PBM
Normal oxygen saturations in healthy adult?
94 - 98% SpO2.
What is respiratory arrest?
When respiration has ‘arrested’ or stopped.
Caused by anything that prevents effective respiration. - causes respiratory failure.
eg, choking, airway trauma.
What is cardiac arrest?
When the heart ‘arrests’ or stops its function
What is a symptom?
Something the patient feels or is aware of.
What is a sign?
Something the clinician can establish through clinical observations and examination. eg, reduced oxygen levels.
-itis meaning
Inflammation.
Function of respiratory system (longer)
-Respiration
-Homeostasis
-Role in blood pH control
-Gas exchange - 02 taken up and C02 released
-CO2 is acidic, so to help lose excess acidity, patient will breathe faster to exhale CO2
-Purify, dampen, and warms incoming air
-Cardiovascular system works closely with RS.
Two parts of respiratory system?
Upper respiratory tract – Nose to larynx
Lower respiratory tract – trachea to alveoli
Conducting zones?
All respiratory passageways that carry air to the terminal bronchioles and beyond
Respiratory zones
Part of the lung that leads into the alveoli and is involved in gas exchange) - respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli.
Nose info?
- Air enters nose by nostrils
- Interior = nasal cavity, divided by midline nasal septum.
- Olfactory receptors for smell are in muscosa in superior art of nasal cavity, beneath ethmoid bone.
- Respiratory mucosa lines nasal cavity.
- Veins warm the air as it flows past.
- The mucus produced by mucosa’s glands moisten the air and traps pathogens and debris.
- Lysozyme enzymes in the mucus destroy bacteria chemically.
- The ciliated cells of the nasal mucosa create a gentle current that moves the contaminated mucus toward the pharynx, where it’s swallowed and digested by stomach juices.
What happens in the nose when it’s very cold.
the cilia allow mucus to accumulate in the nasal cavity.
The lateral walls of the nasal cavity are uneven due to lobes called conchae – projections from the walls of the nasal cavity that increase the air turbulence and SA of mucosa exposed to air.
Why is air turbulence needed in the nasal cavity?
As the air swirls more, inhaled particles are deflected onto the mucosa, and are trapped, so don’t reach the lungs.
The nasal cavity is separated from the oral cavity by a partition, the palate. There is a hard (supported by bone) and soft palate. (Unsupported by bone)
Sinuses info?
The nasal cavity is surrounded by a ring of paranasal sinuses in the frontal, sphenoid, ethmoid and maxillary bones. The sinuses lighten the skull and act as resonance chambers for speech. They also produce mucus, which drains into the nasal cavities.
Pharynx info?
- Muscular tube extending from the posterior of the nasal cavities to the oesophagus.
- Passageway for food and air
- Three regions: nasopharynx, oropharynx, laryngopharynx.
- Food passes through the pharynx and the three regions, and into the oesophagus through the flap called the epiglottis.
- Lined with mucous membrane
- Site of tonsils
- Chamber for speech resonation
- The pharyngotympanic tubes that drain the middle ears, open into the nasopharynx.
- The mucosae are continuous so ear infections may follow a pharyngeal infection.
Larynx info?
- The cartilaginous organ located between the trachea and the pharynx: voice box.
- Passageway for air only.
- Connects laryngopharynx to trachea.
- Formed by 8 rigid hyaline cartilages and elastic cartilages called the epiglottis.
- The largest of the hyaline cartilage is the thyroid cartilage, which protrudes anteriorly - Adams apple
- Cricoid cartilage attaches to first ring cartilage of trachea.
- Mucous membrane folds into vocal cords.
Epiglottis info?
Epiglottis – the elastic cartilage at the back of the throat that covers the glottis during swallowing. It allows the passage of air into the lower respiratory passages.
- It diverts food into oesophagus and protects the superior opening of the larynx
When swallow:
- Larynx is pulled upward
- Epiglottis tips, forming lid over larynx’s opening, and leading food into the oesophagus.
- If anything other than air enters larynx, cough reflux to stop It entering lungs. Reflex doesn’t work when unconscious.
Vocal cords info?
Part of the mucous membrane of the larynx forms a pair of folds called vocal folds, or true vocal cords.
They vibrate with expelled air to produce sound
Vocal cords info?
Part of the mucous membrane of the larynx forms a pair of folds called vocal folds, or true vocal cords.
They vibrate with expelled air to produce sound
Glottis info?
Glottis is the opening between the vocal cords in the larynx. Air must pass through to enter the trachea.
Trachea info?
- The windpipe, the respiratory tube extending from larynx to bronchi. (10-12cm)
- Walls are reinforced with C-shaped rings of hyaline cartilage.
- Open parts of the rings abut the oesophagus and allow the trachea to expand anteriorly when swallowing large bolus.
- Solid rings support the trachea walls and keep it open to withstand the pressure changes during breathing.
- Trachealis muscle lies next to the oesophagus and completes the wall of the trachea.
- Trachea is lined with a ciliated mucosa. Cilia are surrounded by goblet cells that produce mucus.
Cilia info?
Cilia – hairlike projections on cell surfaces that propel mucus (that traps dust and pathogens) to throat to be swallowed or coughed up.
If trachea is blocked, perform Heimlich manoeuvre, or in emergency, tracheostomy (surgical opening of trachea)
Lungs info?
- They occupy entire thoracic cavity except for mediastinum. – region of thoracic cavity between the lungs that houses the heart, great blood vessels, bronchi, oesophagus and other organs. .
- Pulmonary pleura – serous membrane layer covering the cavity in which the lung resides.
- Walls of thoracic cavity lined by parietal pleura.
- Pleural membranes produce pleural fluid, which allows the lungs to glide over the thorax wall during breathing to reduce friction and causes the two pleural layers to cling together.
- Made of elastic connective tissue that allows the lungs to stretch and recoil during breathing.
- Right – 3 lobes ; Left – 2 lobes (due to heart)
Pleurisy info?
Pleurisy – Inflammation of the pleurae – caused by insufficient secretion of pleural fluid. Two types – pleural surfaces become dry, resulting in friction OR pleurae produce excessive fluid, which exerts pressure on lungs.
Alveoli info?
- Air spaces
- Walls of alveoli made of single, thin layer of simple squamous epithelial cells.
- Alveolar pores connect neighbouring air sacs and provide alternative routes for air to reach alveoli whose feeder bronchioles are clogged by mucus or blocked.
- Part of the respiratory membrane, where gas exchange occurs.
- Contains alveolar macrophages that remove pathogens and debris.
- Contain specialised cells that produce surfactant, which prevents alveoli collapse.
- Highly vascular.
Respiratory membrane info?
- Effectively divides gas from fluid
- Site of external respiration
- Made up of 4 layers: - Alveolar walls & basement membrane - Capillary walls & basement membrane
- Huge surface area
- Very thin membrane - for diffusion
- O2 into bloodstream, CO2 into alveoli
Bronchi info?
The left and right primary bronchi are formed by division of trachea. They plunge into the hilum (medial depression of the lung)
Right bronchus is wider, shorter, and straighter than left. It is more common for inhaled objects to become lodged because it is easier to access.
The bronchial tree because of the branching and rebranching of respiratory passageways. All but the smallest branches have reinforcing cartilage in their walls.
Dalton’s Law
The pressure exerted by a mix of gases is the sum of all the partial pressures exerted by each gas within that mix.
Px is the pressure of a specific gas in a mix of gases.
These partial pressures allow diffusion to occur in respiration.
O2 partial pressure measured in mmHg, millimetres of mercury.
Types of respiration?
Internal
- Gas exchange between the capillaries and the cells and tissues.
External
- Gas exchange between the alveoli and the bloodstream.
To supply body with O2 and remove CO2, what happens.
Pulmonary ventilation: air moves into and out of lungs. the exchange of air between the lung alveoli and external environment.
External respiration: Gas exchange between the alveoli and the bloodstream.
Respiratory gas transport: O2 + CO2 transported to and from lungs and cells of body via bloodstream
Internal respiration: Gas exchange between the capillaries and the cells and tissues.
Henry’s Law
the quantity of gas that dissolved into a liquid is proportional to its partial pressure and its solubility.
Oxygen does not dissolve very easily into plasma. (the fluid component of the blood)
FiO2, Fraction of inspired Oxygen