Flashcards in Respiration 2 Deck (23):
What is a disadvantage of the aspiratory pump for ventilation, in amniotes with sprawled posture?
Lateral undulation requires use of the muscles used for breathing, and causes compression on one side while the other expands -> can't ventilate while running (when needed most)
Describe the gills of amphibians
Branchial arches support external gills
What kinds of air breathing organs do fish have? (4 types)
- reinforced gills (supported in air)
- vascularized buccal/pharyngeal cavities (only if soft, smooth food)
- other specialized GIT regions (swallow air)
- labyrinth organ (folded bone dorsal to gills supports highly-vascularized epithelium
Who uses a 2-stroke buccal force pump?
most amphibians, air-breathing Sarcopterygii
Describe the respiratory pump shared by air-breathing Actinopterygii & some aquatic amphibians
4-stroke buccal force pump:
- Expansion 1: glottis (G) open, mouth/nares (MN) closed -> expand buccal cavity (B) -> suck stale air from lungs to mouth
- Compression 1: G closed, MN open -> compress B -> expel stale air
- Expansion 2: G closed, MN open -> expand B -> suck fresh air in from environment
- Compression 2: G open, MN closed -> compress B -> force fresh air from mouth to lungs
Which muscles are involved with the aspiration pump of sauropsids?
Intercostals & other axial
What do crocodilians do to aid the axial muscles used in the aspiratory (ventilation) pump?
Use diaphragmaticus, ischiopubis muscles to pull liver towards tail to expand thoracic cavity
Describe osteichthyes respiratory pump
Dual pump: buccal & opercular pumps
- Suction: expand buccal & opercular cavities -> water in via mouth (to opercular chamber b/c lowest pressure)
- Pressure: close mouth -> contract buccal & opercular cavities -> expel water out over gills
What is an advantage of the aspiratory pump for ventilation, in terms of the buccal cavity?
Buccal cavity not required to pump air/water, so can specialize for specific feeding type (chewing, swallowing large prey, suckling, etc.)
What kinds of amphibians have gills?
Larval salamanders & anurans; some adult salamanders (aquatic)
Describe the ventilation system used by air-breathing Sarcopterygii & most amphibians
2-stroke buccal force pump:
-Expansion: mouth, nares, glottis open -> suck spent & fresh air into buccal cavity
-Compression: (all still open) force mixed air into lungs, excess into environment
Who uses an aspiration pump for ventilation?
Describe the gills of obligate air-breathing fish, and rationale
- reduced surface area, thicker epithelium
- prevents O2 loss in hypoxic water (higher P_O2 in blood), but still allows ion exchange & CO2 excretion
Describe the advantages & disadvantages of external gills. Who has them?
- Advantage: easy to ventilate by flicking around
- Disadvantage: vulnerable to damage (& bleed a lot b/c highly vascularized) & parasite attackes
- Used by amphibians (esp. larvae)
Advantages of breathing air
- less dense than water -> easier to pump
- rarely have O2 shortage because lots available in air
Which muscles are involved with the aspiration pump of mammals?
Diaphragm (not in others), intercostals, other axial muscles
How efficient is the 4-stroke buccal force pump?
Not very - only 1 of 4 stages is used for gas exchange
Who has a dual pump for respiration?
Disadvantages of breathing air
- CO2 much less soluble than in water -> can't just diffuse out through thin skin; regulate ventilation by CO2 levels
- keep gas exchange organs deep in body to retain moisture -> must use less efficient tidal flow
Describe teleost gills
- All in opercular chamber, covered by operculum (dermatocranium)
- primary lamellae extend straight from branchial arches (no interbranchial septa)
- secondary lamellae on either side of primary lamellae
Why is the 2-stroke buccal force pump as bad as it seems?
- even the spent air returning to lungs still contains O2
- timing of glottis & nares opening minimizes air mixing in buccal cavity
- pump buccal cavity between lung breaths to maintain high amount of fresh air
Describe chondrichthyes respiratory pump
Dual pump: buccal & parabranchial pumps
- Suction: expand buccal & parabranchial cavities -> water in via mouth, spiracles (to parabranchial chamber b/c lowest pressure)
- Pressure: close mouth, spiracles -> contract buccal & parabranchial cavities -> expel water out over gills & through flap valves