BIOL 111 Lecture Notes - Lecture 18: Knot, Hagfish, Vertebral Column

• School: McGill University
• Department: Biology (Sci)
• Course: BIOL 111
• Professor: Suzanne Gray

Document Summary

Seem to be an ancestral trait in deuterostomes. Humans have a tail during fetus stage. Bars between the slits = gill arches: bone or cartilage, gill filaments are on the gill arches (insert picture of a) Bony fishes have 4 pairs of gill arches. Bony fish also have a gill cover (operculum) Gill raker becomes smaller if the fish eats smaller food and vice versa. The operculum is a hard structure, which enables the fish to protect its gills. Must remain moist, are highly vascularized, are only 1-2 cells thick, have high surface area (also important, maximize partial pressure gradients between respiratory media; water and blood) Larger surface area and more of them to transfer gases, athletes such as long distance runners have a larger lung capacity. Capillary beds in gill filaments; gas exchange. Water and blood flow in opposing directions water comes in with high oxygen and meets with the blood which has low oxygen.