Intro to Resp, Anatomy of the Lungs, airways Flashcards
Overview of the organisation of resp system?
Upper respiratory system- mouth, nasal cavity, pharynx, larynx
Lower respiratory system- trachea, bronchi, lungs.
The lower respiratory system is enclosed by the thorax, bounded by the ribs, spine and diaphragm.
What are the functions of the respiratory system?
MMOST IMPORTANT-Gas exchange- Oxygen added to the blood from the air, CO2 removed from the blood and into the air.
Acid base balance- regulation of body pH
Protection from infection
Communication via speech
How is pulmonary circulation different to systemic circulation?
Differs in function. Pulmonary circulation delivers CO2 to the lungs and picks up O2.
only includes lungs and heart
very localised and specialised
only concerned with delivering CO2 to the lungs and picking up O2 from the lungs and delivering to the heart
What does external respiration require?
Requires integration of the respiratory system and cardiovascular system.
For example the changes that occur during exercise.
Working muscle leads to an increase in energy demand, leading to:
Rate and depth of breathing speeds up-> substrate (O2) acquisition
Waste disposal (CO2)
Heart rate and force of contraction speeds up-> substrate delivery to muscle via blood
Waste removal via blood
What helps to prevent gas build up in the circulation which would hamper gas exchange?
In the steady state, the net volume of oxygen exchanged in the lungs per unit time is equal to the net volume exchanged in the tissues.
Same applies for CO2.
What is the average volumes exchanged per minute?
250 ml oxygen exchanged (consumed)
200 ml carbon dioxide exchanged (produced)
Breathing rate is 10-20 breaths/min at rest, 40 - 45 at maximum exercise in adults
Anterior view of the thoracic cavity
Look at notes
Describe the branching of airways
The trachea branches to two bronchi, one to each lung. Each bronchus branches 22 more times, finally terminating in a cluster of alveoli.
How are the larynx, trachea and primary branched bronchus “patent?”
C shaped rings of carilage
How Is latency tainted in the secondary branched bronchus and bronchiole?
Physical forces in thorax
Point of gas exchange between the lungs and the blood?
Alveoli (they have very thin walls and gas exchange is enhanced by the huge surface ara of the alveoli).
What does the walls of upper resp tract mean?
The walls of the upper airways are too thick to allow gases to cross and their function is purely conduction of air to and from the alveoli.
The air in these airways is known as Anatomical dead space because it cannot participate in pas exchange.
Where does most resistance to air flow occur?
CONDUCTING ZONE-Trachea, primary bronchi, smaller bronchi
How is resistance to air flow altered?
Airway diameter and therefore resistance to air flow can be altered by activity of bronchial smooth muscle i.e.
Contraction decreases the diameter of the airways -> increase resistance
Relaxation increases diameter of the airways -> decreases resistance
What is the structure of alveoli?
Composed of Type 1 cells for gas exchange and type 2 cells that synthesize surfactant cells. Alveolar macrophages ingest foreign material that reaches the alveoli.
Each cluster of alveolis are surrounded by elastic fibres and a network of capillaries.
