Chapter 30 - Human Breathing Flashcards
Name two functions of the nose
Filters air by hairs and mucous
Moistens and warms the air
Why is it important for air to be moist and warm
Helps with diffusion of air from lungs to bloodstream
Prevents alveoli from drying out
Name two functions of the pharynx
Epiglottis closes off trachea when swallowing
Voicebox (larynx) contains 2 vocal cords that produce sound
What is the trachea made of
Muscle and elastic fibers
Has c-shaped rings of cartilage around it to prevent it from collapsing
Inside is lined with mucous and silia which traps dust and bacteria
What is the function of the trachea
Allows air to travel down into the bronchi and bronchioles
Describe the lungs
Spongy structure
Enclosed by a pair of pleural membranes - liquid to prevent friction between the lungs
What are alveoli
Hollow air sacs at the end of bronchioles
700 million in the lungs
They are surrounded by capillaries
What is the function of alveoli
Gas exchange through diffusion
How does deoxygenated blood enter the lungs
Pulmonary artery
How does oxygenated blood leave the lungs
Pulmonary vein
What gases are inhaled
78% nitrogen
21% oxygen
0.04% carbon dioxide
1% water
What gases are exhaled
78% nitrogen
16% oxygen
4% carbon dioxide
2% water
How does blood travel to the body cells
Oxygenated blood goes to the cell through the aorta
Oxygen diffuses into the cell
Carbon dioxide and water vapor diffuses out of the cell and travels through the vena cava
How is oxygen transported
Through hemoglobin
How is carbon dioxide and water vapor transorted
By plasma
What are three adaptations to improved gas exchange
Alveoli have thin walls
Alveoli are moist
Capillaries are numerous
Describe inhalation (inspiration)
- Diaphragm and intercostal muscles contract - active process
- Ribs are pulled up and out, diaphragm moves down
- Volume of thorax increases
- Pressure in thorax falls
- External air pressure higher so air is forced into the lungs
Describe exhalation (expiration)
- Diaphragm and intercostal muscles relax - passive process
- Ribs are pulled down and in, diaphragm moves up
- Volume of thorax decreases
- Pressure in thorax increases
- Air is forced out of lungs
What controls rate of breathing
The brain
How does the brain control rate of breathing
Detects levels of carbon dioxide in the plasma by the slight drop in ph due to carbonic acid - caused by exercise
Name a breathing disorder
Asthma
What are symptoms of this breathing disorder
Noisy, wheezy breathing, feeling of breathlessness
Causes of this breathing disorder
Attacks triggered by infections, exercise, allergens
Lower bronchioles become constricted
Prevention of this breathing disorder
Avoiding allergens
Preventative inhalers
Treatment for this breathing disorder
Inhalers (bronchodialators) - dilate bronchioles
Inhalers - steroids may be inhaled
Injections - severe cases
