lungs and gas exchange Flashcards
why are the lungs inside the body?`
- air is not dense enough to support and protect delicate structure
- body would lose a lot of water
why does a large volume of oxygen and carbon dioxide need to be exchanged?
- mammals have a large volume of cells
- in order to maintain high body temperature relating to high metabolic rate and respiratory rate
what is the trachea?
flexible airway that is supported by cartilage1
what is the role of the cartilage?
prevents trachea from collapsing by maintaining pressure
- it is a C-shaped ring with expansion potential allowing it to control the size/width of the trachea
name three features found in trachea, bronchus and bronchioles
- goblet cells
- ciliated epithelial cells
- smooth muscle
what is the role of the goblet cells?
produces mucus which traps microorganisms
what is the role of ciliated epithelial cells?
prevents mucus getting into lungs by sweeping up to back of the throat to be swallowed by stomach acid
how does the contraction and relaxation of muscle affect the airway?
- contraction - airway narrow - restricted airflow (toxic area)
- relaxation - wider airway - greater airflow
why is ventilation necessary?
to maintain diffusion of gases across alveolar epithelium
what is inhalation?
when the air pressure of the atmosphere is greater than the air pressure in lungs so air is forced in
what is exhalation?
when the air pressure of the lungs is greater than the air pressure in atmosphere so air is forced out
what three muscles are involved in ventilation?
- diaphragm
- internal intercostal muscles
- external intercostal muscles
explain how inhalation works
- external intercostal muscles contract (internal relax)
- ribs: up and out
- diaphragm moves down increasing thoracic volume
- reduction of pressure in lungs and atmospheric pressure is greater than pulmonary pressure so air moves in
explain how exhalation works
- internal intercostal muscles contract (external relax)
- ribs: down and in
- diaphragm moves up decreasing thoracic volume
- increase of pressure in lungs and atmospheric pressure is less than pulmonary pressure so air moves out
what is tidal volume?
volume of air taken in at each breath when body at rest
