Module 10 - Respiratory system Flashcards
Respiratory organs in fish?
gills
Gills are made of … ?
dense capillary beds
Where are gills located?
internally - associated with pharyngeal slits & pouches
externally - arise in branchial regions as filamentous capillary beds
How does respiration occur in internal gills?
via muscular pump of buccal cavity -> actively drives water across internal gills
How does respiration occur in external gills?
water currents flow across projecting surfaces (moving water currents)
specialised muscles sweep external gills back & forth to ventilate them
A bit on gas bladders
elongated sac filled with gas from:
- air via pneumatic duct connected to digestive tract
- secreted directly into bladder from blood
aids in buoyancy control (swim bladder) & resp. (lungs)
How does the swim bladder differ from the lungs? 3 ways…
- situated dorsal to digestive tract (lungs - ventral)
- single (lungs - paired)
- returning blood drains to general systemic circulation (separate venous return from lungs)
Similarities between swim bladder & lungs…?
- both have outpocketings from gut or pharynx
- have roughly equivalent nerve & muscle supply
Compare different lung anatomy of mammals, birds, amphibians, and reptiles…?
mammals - alveoli for gas exchange as do birds
amphibians - range from simple sacs + few blood vessels to pouches divided into many large compartments with dense vascularisation
reptiles - rely on bellows-like pumping of posterior sacs facilitating air flow
Hilus of each lung located …?
near middle of medial side
What is the hilus?
Area where structures that form root of lung enter & leave viscus such as bronchus, pulmonary artery & nerves enter, pulmonary vein & lymphatic vessels leave
Describe the structures from trachea to gas exchange in alveoli…
slide 13
How is naming of lobes of the lungs based?
depending on subdivision of bronchi - NOT external subdivisions of lungs
How do cow, sheep, and pig lungs differ from horse lungs?
C. S. P. (and all other domestic animals) have cranial, middle, caudal & accessory/intermediate lobe of right lung.
Horse - no lobes except accessory/intermediate lobe of right lung
Describe the gas exchange process of marine mammals on land or water surface
O2 from air -> -> -> skeletal muscle via cardiopulmonary sys
Also, O2 & energy stores in tissue of each major anatomical compartment…
(Practice describing to someone)
What happens during a dive…?
ambient O2 not available -> lungs collapse with increased hydrostatic pressure -> bradycardia -> decreased CO -> change blood distribution -> change in O2 transport to skeletal muscle
What is different about sea otters & dugongs’ lung volumes?
They have larger than expected volume capacities
What changes occur to respiratory tract structures at depth?
Lungs, trachea, bronchi, and alveoli collapse
Which structure determines depth of diving in marine mammals?
rigidity of trachea - partial calcification of tracheal rings prohibits deep diving (eg. river otter)
Which animals have lesser calcification of the trachea, enabling deep diving?
harp seals & walrus
How are lungs protected during a dive?
Airways are reinforced by muscle or cartilage to ensure patency during lung compression at depth -> allows progressive collapse of lung structures during increased hydrostatic pressure from alveoli -> small -> large airways
(Works in reverse when ascending)
How are the lungs of seals & whales protected?
seals - large SM’s surround non-cartilaginous portion of bronchiole connecting to resp. bronchiole & finally alveoli
whales - cartilaginous reinforced airways leading directly to alveoli
Explain why marine mammals can stay submerged whilst highly active for long periods
Contain exceptionally large stores of O2 in LUNGS, BLOOD & MUSCLE -> aerobic activity
Total O2 stores in marine mammals relative to terrestrial mammals?
2-3 times > than terrestrial spp.
Dolphins O2 distributions?
22-24% stored in lungs, rest in blood & skeletal muscle
Deep divers (Weddell seals) O2 distributions?
> 87% in blood & skeletal muscle
How do ‘elite divers’ overcome blood nitrogen tensions at depth?
collapsible lungs -> air into upper airways away from blood
Up to slide 28…
avian respiration
