Anatomy of the Respiratory System Flashcards
The pulmonary arteries carry deoxygenated blood; True or False?
True
What are the different types of cells in the alveoli of the lung?
- Type I pneumocyte
- Type II pneumocyte
What are type I pneumocytes?
Simple squamous epithelium make up approximately 95-97% of the surface area of alveoli. They are thin which allows the rapid diffusion of gases
What is classed as the upper respiratory tract?
- Nasal cavity
- Mouth
- Pharynx
- Larynx
What is classed as the lower respiratory tract?
- Trachea
- Bronchi
- Left and right lung
What are type II pneumocytes, and what is their function?
Thicker cells than Type I pneumocytes. These cells:
- Synthesise surfactant
- Transport solutes (and thus fluid) out of the alveolar air space
How does the respiratory tract lining progress from the nasal cavity to the alveoli?
Pseudostratified ciliated columnar epithelium (upper and proximal lower resp. tract) to simple squamous epithelium (type I and II pneumocytes).
Why does the lung stick to the wall of the chest cavity?
Cohesive forces exerted by the fluid between the visceral and parietal pleura cause the lungs to “stick” to the thoracic cavity wall. The elastic recoil of the lungs constantly tries to pull the visceral pleura away from the parietal pleura, which is counteracted by the outward pull of the thoracic cage.
The stickiness is created subatmospheric pressure the is created by the parietal and visceral pleura pulling away from each other
.
What is the resting pressure of the pleural space?
-3 mmHg
What does the intrapleural pressure fall to on inspiration?
-6 mmHg on normal breathing
What is the intrapleural pressure relative to the alveolar pressure?
More negative - whenever alveolar pressure falls below atmospheric pressure, this pulls air into the lungs
What are the muscles used in inspiration?
- Diaphragm
- Scalenes
- External intercostal muscles
- Sternocleidomastoid
How to the external intercostal muscles help with inspiration?
Pull the ribs upwards and outwards
How do the scalenes help expand the chest?
Pull the ribs upwards and outwards
How do the internal intercostal muscles help with expiration?
Force rib cage downwards and pull ribs inwards
How do the abdominal muscles aid expiration?
Pulls lower rib cage inwards and reduces abdominal volume, which displaces abdominal viscera upwards, displacing thoracic cavity volume
How does the sternocleidomastoid muscle help with inspiration?
Pulls ribs upwards