Flashcards in Respiratory System Deck (138)
Define external respiration
The process in the lungs by which oxygen is absorbed from the atmosphere into blood within the pulmonary capillaries, and carbon dioxide is excreted.
Define internal (or tissue) respiration
Describes the exchange of gases between the blood in systemic capillaries and the tissue fluid and cells which surround them.
Define cellular respiration
The process within individual cells through hitch they gain energy by breaking down molecules such as glucose. It occurs in mitochondria, consumes oxygen and generates carbon dioxide.
What is meant by pulmonary ventilation?
Breathing: describes the bulk movement of the air into and out of the lungs. The ventilator pump comprises the rib cage with its associated muscles and the diaphragm.
Distinguish between the conducting part and the respiratory part of the respiratory system.
Conducting: A series of cavities and thick-walled tubes which conduct air between the nose and the deepest recesses of the lungs, and in doing so warm, humidity and clean it. The conducting airways are the nasal cavities, pharynx, larynx, trachea, bronchi and bronchioles.
Respiratory: Comprises the tiny, thin-walled airways where gases are exchanged between air and blood. The airways are respiratory bronchioles, alveolar ducts and sacs, and the alveoli themselves.
What is required for efficient gas exchange?
Air must be humidified to 100%, warmed, and filtered to clean it.
Describe the nasal cavity.
A tall, narrow chamber lined with mucous membrane. The wet membrane humidifies and warms inspired air.
Describe the medial and lateral surfaces of the nasal cavity.
Medial surface is flat. The lateral surface carries three sloping shelves (conchae) which increase the SA of the mucous membrane.
What are the paranasal sinuses? What are their functions?
They are air-filled sinuses that open into the cavity. They lighten the face and add resonance to the voice.
What does the roof of the cavity carry? What does turbulence cause? Where do olfactory axons lead from and to?
The roof of the cavity carries the olfactory epithelium. Turbulence caused by sniffing carries air up to the epithelium. Axons of olfactory receptor cells lead towards the brain through perforations in the overlying bone, the cribriform plate.
What are the three parts of the pharynx?
Nasopharynx - Air
Oropharynx - Air and Food
Laryngopharynx - Air and Food
What happens during swallowing?
Soft palate closes nasopharynx to push bolus down. Glottis is closed passively (no active mechanism or muscle contraction involved) and the oesophagus is forced open.
Describe the pharynx.
A vertical passage with three parts, each having an anterior opening. The pharynx is an airway, but also a food way. In terms of its structure, it is primarily part of the gastrointestinal system.
What is rhinositus
Chronic sinus infection
What is the glottis?
The entrance to the larynx
Cartilage does not continue beyond the _______ _____. ________ _______ stop there too.
The respiratory system always branches ____________. What does this means?
Every tube branches into 2 tubes
List the structures of the respiratory system from largest to smallest and state their generations.
Main stem bronchi (1)
Lobar bronchi (2)
Segmental bronchi (3)
Smaller bronchi (4-9)
Terminal bronchioles (16-19)
Respiratory bronchioles (20-23)
Alveolar ducts (24-27)
Alveolar sacs (28)
What is the main function of the trachea?
Open the airway
What is the size of the trachea?
The windpipe is a tube about 12 cm long and as thick as your thumb
What is the structure of the trachea?
Supported by incomplete C-shaped rings of cartilage. Free ends of the cartilage are connected by trachealis muscle (smooth) and contraction narrows the diameter of the trachea.
What is the trachea lined with?
Lined with ciliated epithelium (pseudostratified columnar). Cilia transport a mucous sheet upwards to the nasopharynx (the mucociliary escalator).
Where doe the oesophagus sit?
Oesophagus sits immediately posterior to the trachea, lying in the shallow groove formed by the trachealis muscle.
What does coughing involve?
Contraction of trachealis and thus changes in pressure.
How does smoking affect the trachea?
Chemicals destroy cilia. Can only remove mucous by coughing.
Describe the wall of a bronchus.
Thicker and more complex. More responsible for conducting of air.
- Pseudo-stratified ciliated epithelium
- Goblet cells
- Smooth muscle
- Muco/serous glands
Describe the action of goblet cells.
First source of mucous
Contains concentrated dry mucous. When it mixes with water, it expands to create more mucous.
Describe the wall of a bronchiole and what is found in it.
Smaller in diameter. Responsible for control of flow of air.
- Club cells
- Ciliated epithelium (not pseudostratified - transitional from columnar to cuboidal)
- Smooth muscle
What does smooth muscle control in the airways? What does asthma involve? How is it treated?
Flow of air into the respiratory zone. Asthma involves contraction of smooth muscles. Bronchodilator relaxes smooth muscle.