1 Intro to lungs Flashcards
What are the functios of the respiratory system?
Gas exchange
Regulating body pH
Protection from infection
Speech
What is external respiration?
Movement of gases between the air and body cells involving integration of the respiratory and cardiovascular systems.
What is the differance between pulmonary & systemic circulation?
Pulmonary circ. delivers CO2 to lung tissue & collects oxygen.
Systemic circulation collects CO2 from body tissues & delivers oxygen.
What are the sections of the pulmonary circulation?
The pulmonary artery carries CO2 from heart -> lungs.
The pulmonary vein carries oxygen towards the heart from lungs.
What are the 3 gas exchanges in circulation?
1) Between free air & lung tissue
2) between lung tissue & pulmonary circulation
3) Between systemic circulation & cells.
What is the steady state of oxygen supply mean?
Net volume of O2 exchanged in lungs = net volume of O2 exchanged in the tissues.
What is the benefit of the oxygen steady state?
It prevents gas building up in the circulation and ensures supply = demand.
What is the average volume of O2 consumed & CO2 produced?
250ml O2 per min
200ml of CO2 per min
What are the average no. of breaths per minute?
10-20 breaths per min at rest
40-45 breaths per min at max exercise
What are the 6 sections of the respiratory system in descending order?
Nose Pharynx Epiglottis Larynx Trachea Bronchus
What does the nose do?
Air enters body through nose
Cilia & mucus there trap particles & warm/moisten the air.
What does the pharynx do?
Air from nose travels here
Shared part of throat with digestive system
What is the epiglottis?
A flap of elastic cartilage that covers the entrance to the larynx during swallowing to prevent choking on food.
Whats the purpose of the larynx?
Contains the vocal chords which vibrate for sound
What is the function of the trachea?
Funnels air from the pharynx to the lungs
What makes up the trachea?
Stiff rings of cartilage for support & protection
What do the bronchi do?
funnel air from the trachea to the lung tissue
What makes up the upper respiratory tract?
Mouth
Nasal Cavity
Pharynx
Larynx
What makes up the lower respiratory tract?
Trachea
Bronchi
Lungs
What encloses & binds the lower respiratory tract?
The thorax enclsoes the lower respiratory tract.
Its bound by ribs, spine & diaphragm.
What is the differnace between the 2 bronchi?
The right bronchus is shorter, wider and steeper.
This often causes aspirated foreign bodies to lodge in the right bronchus.
What is patency?
The condition of being open or unobstructed
How is the patency of the larynx, trachea & bronchi maintained?
By C-shaped rings of cartilage
How is the patency of the bronchiole maintained?
By physical forces in the thorax
Ho is the airway diameter & respistance to flow altered?
By bornchial smooth muscle
What is a lobule?
A cluster of alveoli
Each cluster surrounded by elastic fibres & capillaries
What are alveolar cells called?
Pneumocytes
Detail type one alveolar cells?
- Responsible for gas exchange
- 97% of alveolar surface
- Simple squamous epithelium
Detail type two alveolar cells?
- Syntehsize surfactant
- High in phospholipids & protein
What does surfactant do?
- REuces alveolar surface tension
- Reduces effort of breathing
What happens to any foreign material reaches the alveoli?
Its ingested by macrophages
Why can gas exchange only occur at the alveoli?
In the higher airways the walls are too big the air is known as anatomical dead space
What makes alveoli so good at gas exchange?
Very thin walls
Large surface area.
How does the airway lining change from the nose-> alveoli?
- EPithelium becomes more squamous
- Cilia is lost
- Mucous is lost
What does mucuous do?
Traps particles & moistens the air.
Provides a large surface area for cilia to act on
Where is mucous made?
Goblet cells
Sub-epithelial glands
Wjat type of cell are type 1 pneumocytes?
Simple squamous epithelium
