1 Intro to lungs Flashcards
What are the functions of the respiratory system?
Gas exchange
Regulating body pH
Protection from infection
Speech
What is external respiration?
Movement of gases between air and body cells
Involves integration of respiratory and cardiovascular systems
What is the difference 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?
Pulmonary artery carries CO2 from heart -> lungs
Pulmonary vein carries oxygen towards 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 tissues
What is the benefit of the oxygen steady state?
Prevents gas build up in circulation
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 trap particles & warm/moisten air
What does the pharynx do?
Air from nose travels here
Shared part of throat with digestive system
What is the epiglottis?
Flap of elastic cartilage that covers entrance to the larynx during swallowing to prevent choking on food
Whats the purpose of the larynx?
Contains vocal chords which vibrate for sound
What is the function of the trachea?
Funnels air from the pharynx to lungs
What makes up the trachea?
Stiff rings of cartilage for support & protection
What do the bronchi do?
Funnel air from trachea to 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?
Thorax encloses lower respiratory tract.
It is bound by ribs, spine & diaphragm.
What is the differnace between the 2 bronchi?
Right bronchus is shorter, wider, steeper.
This often causes aspirated foreign bodies to lodge in right bronchus
What is patency?
Condition (State) 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 thorax
How is the airway diameter & resistance 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 l alveolar cells?
- Responsible for gas exchange
- 97% of alveolar surface
- Simple squamous epithelium
Detail type ll alveolar cells?
- Syntehsize surfactant
- High in phospholipids & protein
What does surfactant do?
- Reduces alveolar surface tension
- Reduces effort of breathing
What happens to any foreign material reaches the alveoli?
Ingested by macrophages
Why can gas exchange only occur at the alveoli?
Higher airway walls are too big
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 air
Provides large surface area for cilia to act on
Where is mucous made?
Goblet cells
Sub-epithelial glands
