Human gaseous Exchange Flashcards
What does the human respiratory system consist of?
Air passages
Lungs
Respiratory muscles
What does the air passages include? interns of parts?
Nasel passages
Pharynx (thought)
Trachea (windpipe)
Bronchi
Bronchioli
What are the adaptions of the air passages?
Nasel cavities have hairs= filters large dust particals from inhaled air.
All passages are lined with a mucous membrane of ciliated columnar cells= warms incoming air, traps dust and germs, moistens incoming air and carries dust and germ-carrying mucus toward the outside
Opening to the trachea closed by epiglottis= Prevents chocking when swallowing
Trachea walls suspported by c-shaped cartilage rings= supports and keeps trachea open.
Open sides of C-shaped rings in contact with oesphagus= able to stretch during swallowing
Lungs
What does the external srtucture of the lungs consist of?
- The two lungs are located in the chest
- The lungs are supproted and protected by 12 pairs of ribs
- The intercostal muscles are found between the ribs
- The righ lungs consists of 3 lobes where the left consists of 2
- The lungs are spongy and elastic
- Each lung is surounded by a double membrane the pleura
- There is intrapleural fluid bewtween pleura membranes that prevents friction
- The lungs are conical and rest at the bottom on a dome-shaped mucle plate, the Diaphragm
Lungs
What is the internal structure of the lungs like?
- Inside the lungs are bronchi which branch out, which become smaller and form bronchioli
- As the become smaller, they lose cartilage and end in lung sacs, which consist of groups of* alveoli*.
- The walls of the alveoli are very thin and consist of a single layer of Squamos epithelium
- The alveoli are surrounded by a network of capilaries
- The walls of the capilaries consist of a single layer of squamous epithelium (endothelium)
Lungs
How is the lungs adapted for their fuction?
- The lungs are spongy and elastic= can expand and contract easily
- Lungs are surrounded by a double membrane, with intraplueral fluid in between the membranes= prevents friction
- Bronchioli eventually end in millions of alveoli= increases the gaseous exchange surface
- The wall of an alveolus consists of a single layer of squamos epithelium= thin surface for efficient gaseous exchange
- Alveoli are surrouned by a network of blood capilaries= transport of Oxygen to the tissies and Carbon dioxide to the lungs
- Walls of the blood capillaries consist of a single layer of endothelium= thin surface for effecient gaseous exchange
Respiratory mucles
What are the diffrent mucles that play a role during breathing?
The diaphragm and the intercostal mucles.
Respitory Mucles
What roles does the diaphragm play in breathing?
in its relaxed state, the diaphragm is a dome-shaped mucles plate, this mucles plate seperates the chest and abdomen to from and airtight thoracic cavity. It playes a role in inhalation, the diaphragm contracts and becomes flatter. it also plays a roe in exhalation where it relaxes and returns to its orginal dome shape.
What two phases does ventilation of the lungs take place?
inhalation and exhalation
what is the ventilation of the lungs?
it is the movement of the air between the atmosphere and lungs which causes a diffrence in air pressure between the atmospheric air and the air in the thoracic cavity and alveoli. it is also the movement of the respitory muscles that changes the volume of the thoracic cavity which causes the diffrence in pressure.
Explain the inhalation process.
- the diaphragm contracts and becomes flatter
- Thoracic cavity enlarges from top to bottom
- The external intercostal mucles contract, causeng the ribs to move upwards and outwards.
- The thoracic cavity enlarges from side to side and from front to back
- The abdominal mucles relax so that the abdominal cavity can accomadate the internal organs being pushed down by the diaphragm
- The total volume of the thoracic cavity is increased
- The pressure in the thoracic cavity and lungs decrease
- the elastic lungs expand
- Oxygen-rich air flows into the lungs becouse the atmospheric pressure is higher than that of the thoracic cavity and the lungs.
Explain the exhalation proccess
- The diaphragm relaxes and returns to its original dome shape
- The thoracic cavity becomes smaller from top to bottom
- The external intercostal muscles relax, causing the ribs to move downward and inward
- The thoracic cavity reduces in size from side to side and from front to back
- the total volume of teh thoracic cavity is reduced
- The pressure in the thoracic cavity and lungs increase
- carbon dioxide-rich air flows out of the luns becouse, the pressure in the chest cavity and lungs is higher than that of the atmospheric pressure.
Explain the exchange of Oxygen in the alveoli.
- The inhaled air in the alveoli has a higher Oxygen concentration than the blood in surroundinngn cappilaries
- a diffusion gradient is therefor created between the air in the alveoli and teh blood in the capilaries
- The Oxygeen dissolves in a thin layer of moisture that lines the alveoli and diffuses through the thin walls of the squamous epithelium of teh alveoli and endothelial walls of the capilaries into the blood
Explain the exchange of the Carbon dioxide in the alveoli.
- The blood that reaches the alveoli from the tissues has a higher Carbon dioxide concentration than the air in the alveoli
- a diffusion gradietn is therefore created between the blood in the capilaries and the air in the alveoli
- Carbon dioxide diffuses from teh blood in the capillaries through the endothelial walls of the capillaries and thin squamous epithelial walls of alveoli into tho air in the alveoli
Explain the exchange of Oxygen in the tissues.
- Oxygenated blood reaches the tissues
- The blood in the capillaries has a higher Oxygen concentration than the cells of the tissue
- a diffusion gradient is therefor created between the blood in the capillaries and the cells
- The Oxygen diffuses through the endothelial walls that surrounds the cells and into the cells
