Exchange Surfaces - Lung structure and Breathing Flashcards
where is cartilage found in the lungs
trachea and bronchi
what is the function of elastic fibres in the lungs
stretch and recoil of elastic tissue widens the airways (after contraction) and forces air out of alveoli (after expansion). Stops alveoli from bursting when breathing in.
what is the function of cartilage in the lungs
support, holds them open and prevents collapse
where is smooth muscle found in the lungs
walls of trachea, bronchi and bronchioles
what is the function of smooth muscle in the lungs
involuntary muscle that contracts to narrow the lumen (allows air to move in and out)
where are goblet cells found in lungs
throughout ciliated epithelium
what is the function of goblet cells in lungs
secrete sticky mucus to trap particles and prevent them drying out
where is ciliated epithelium found in lungs
lines the trachea, bronchus and bronchioles
what is the function of ciliated epithelium in lungs
cilia move in a synchronised pattern to waft mucus up the airway to the back of the throat
describe cartilage in the trachea
large c-shaped pieces
which tissues are found in the trachea
- cartilage
- smooth muscle
- elastic fibres
- ciliated epithelium
describe cartilage in bronchi
smaller pieces
which tissues are found in the bronchi
- cartilage
- smooth muscle
- elastic fibres
- ciliated epithelium
which tissues are found in the larger bronchiole
- smooth muscle
- elastic fibres
- ciliated epithelium
which tissues are found in the smaller bronchiole
- smooth muscle
- elastic fibres
- ciliated epithelium
which tissues are found in the smallest bronchiole
- elastic fibres
- epithelium
which tissues are found in the alveoli
- elastic fibres
- epithelium
describe inspiration
- contraction of external intercostal muscles causes ribcage to move up and out
- contraction of muscles in the diaphragm causing it to go downwards/flatten
- increases volume of the thoracic cavity
- pressure within the thoracic cavity is lowered (below outside pressure)
- air flows in through nose and mouth down the pressure gradient into the thorax, through trachea, bronchi and bronchioles.
describe expiration
- external intercostal and diaphragm muscles relax
- elastic fibres between the alveoli recoil back to their normal length
- volume decreases and pressure increases forcing air out
describe forced breathing out
- more air can be forced out by the contraction of the internal intercostal muscles moving ribcage down and in
- contraction of abdominal muscles raises diaphragm
how is the nasal cavity adapted for efficient gas exchange
- large surface area
- good blood supply
- mucus
- moist surfaces
