3.1 exchange surfaces Flashcards
What is the role of surfactant in the lungs
maintain surface tension so the alveoli does not get too over stretched
Why is a baby’s first breath difficult
large change in atmospheric pressure as the lungs are filled with fluid
What happens to the diaphragm during inspiration
contraction
What happens to the diaphragm during expiration
relaxation
What happens to the external intercostal muscles during inspiration
contract
What happens to the internal intercostal muscles during inspiration
relax
What happens to the external intercostal muscles during expiration
relax
What happens to the internal intercostal muscles during expiration
contract
What happens to the rib cage during inspiration
up and out
What happens to the rib cage during expiration
down and in
What happens to the thoraic volume during inspiration
increases
What happens to the thoraic volume during expiration
decreases
What happens to the intrapulmonary pressure during inspiration
decreases
What happens to the intrapulmonary pressure during expiration
increases
What happens to the air movement during inspiration
pressure falls below atmospheric pressure so air is drawn inside
What happens to the air movement during expiration
pressure goes above the atmospheric pressure so air moves out
What structures does a trachea contain
- cartilage
- smooth muscle
- elastic fibres
- ciliated epithelium
- goblet cells
- mucous glands
What structures does the bronchi contain
- cartilage
- smooth muscle
- elastic fibres
- ciliated epithelium
- goblet cells
- mucous glands
What structures does the larger bronchioles contain
- smooth muscle
- elastic fibres
- ciliated epithelium
- goblet cells
What structures does the smaller bronchioles contian
- smooth muscle
- elastic fibres
What structures does the smallest bronchioles contain
elastic fibres
What structures does the alevoli contain
elastic fibres
Function of cartilage
to support the trachae and ensure airway is open
Function of the ciliated epithelium
cilia on the surface which sweep mucus, dust and bacteria upwards
Function of goblet cells
secrete mucus
Function of smooth muscle
adjust size of airways
Function of squamous epithelium
short diffusion pathway for rapid gaseous exchange
Function of elastic tissue
recoil
Define alveolar air
air located in the alveoli that takes part in gaseous exchange
Define tidal volume
volume of air that moves in and out of the lungs with each breath at rest
Define residual volume
volume of air that is left in the lungs after maximum exhilation
Define vital capacity
volume of air that can be breathed in after maximum exhilation
Define dead space air
volume of ventilated air that isn’t participating in gaseous exchange
Define inspiratory reserve volume
maximum volume of air you can breathe in after normal inhilation
Define expiratory reserve volume
maximum volume of air that can be exhaled after normal exhilation
Define total lung capacity
vital capacity + residual volume
What is the counter current system in fish
- opposite directional flow of water and blood
- maintains concentration gradient in the capillary
What is the ventilation mechanism in fish
- when the fish open their mouths the lower the floor of the buccal cavity
- volume inside the buccal cavity increases so there is a decrease in pressure inside
- the pressure is higher outside than inside so water flows in
- the fish then raises the floor of the buccal cavity increasing the pressure
- water flows outwards to the gill cavity
- as water pressure builds in the gill cavity the operculum forces open and water exits the fish
What is the ventilation mechanism in insects
- very active, flying insects need more oxygen
- they create mass flow by closing the spiracles and using abdominal muscles to create a pumping movement
Structure to function of the alveoli
- small = large SA:V ratio
- constant blood flow = step concentration gradient
- 1 cell thick = shorter diffusion distance
- large number = increases SA
- contains surfactant = maintains surface tension
- contains elastin = allows recoil
