17. Fish Flashcards
Function of pharyngeal slits (pouches)?
- Filter feeding
- Respiration in vertebrates
…
…
Gills are used for…
Exchange of O2 and CO2 (respiratory surface)
Pharyngeal slits can become…
Gill slits
What are the bars between the slits?
Gill arches (bone or cartilage)
What is on the gill arches?
Gill filaments
How many pairs of gill arches in bony fishes?
4 (each arch has pairs of gill filaments) _ gill cover (operculum) to protect
Gill filament structure = ……., ……, ……. area
Thin, vascularized, high surface
Blood flow and water in gill filament?
- Blood vessel flow through gill arches
- Capillary beds in gill filaments (gas exchange - filament only one cell thick)
- Water & Blood flow in opposing directions (counter-current exchange system)
Explain countercurrent exchange.
- Blood flows in opposite direction to water flow
- Ensures that concentration gradients are maintained
- Achieves maximum exchange of gases
(the more oxygenated the water, the more oxygenated the blood)
Describe the fish circulatory system
- Closed (arteries, arterioles, capillaries, venules, veins) (not quite like ours, we have pulmonary and systemic (lungs vs body), but not the fish)
Describe the fish heart
2 chambers & folded (blood comes in through sinus venosus, the one-way valves inside, atrium, ventricle, bulbous arteriosus) - found ventrally
Characteristics of vertebrates?
- Axial skeleton (cranium, vertebral column, ribs)
- Apendicular skeleton (pectoral girdle, pelvic girdle)
- Closed circulatory system (with ventral heart)
- Organs suspended in coelom
Fish make up what % of vertebrate diversity?
50%
What are gnathostomes?
Jaw fishes