17. Characteristics of chordates Flashcards
Where are pharyngeal slits (pouches)?
Lateral surface of head
Characteristics unique to chordates
- Dorsal hollow nerve cord
- Notochord
- Muscular post-anal tail
Pharyngeal slits seem to be an …… in ….
Ancestral trait in deuterostomes (lost in echinoderms)
In vertebrates, pharyngeal tissue is supported by…
Arches
Function of pharyngeal slits?
- Filter feeding
- Respiration (IN VERTEBRATES)
How do pharyngeal slits allow respiration?
- Water coming in mouth passes through slits
- O2/CO2 can be exchanged across respiratory surface (gills)
Pharyngeal slits = …
Gill slits
Gill filaments?
On the gill arches
Gill filament structure?
- Thin, vascularized, high surface area
Water & blood flow in gill filament?
Opposing direction (countercurrent exchange)
- Ensures that concentration gradients are maintained
- Achieves maximum exchange of gases
Circulatory system of fish?
- Closed
- Heart –> arteries –> arterioles –> capillaries –> venules –> veins –> heart
Fish have no …. circuits
- Pulmonary (heart, lungs, heart)
- Systemic (heart, body, heart)
Fish heart = …
2 chambers & folded
Characteristics of fish heart?
- Strong, muscular pum
- Ventral
- Maintains blood flow
- 1-way valves inside
Skeleton of vertebrates?
- Axial (cranium, vertebral, ribs)
- Appendicular (pectoral and pelvic girdles)
