BIOL 101 Lecture Notes - Lecture 23: Arrector Pili Muscle, Hair Follicle, Sebaceous Gland
Document Summary
Amniota: anapsids (ancestral amniotes, diapsids (reptilia, synapsida (mammals) Body temperature derived from internal metabolic activity. Habitat selection temperature is independent, as long as it has a food source. Opposite condition: ectothermy: body temperature derived from heat acquired from the environment. Grow out of the hair follicle in the epidermis. Arrector pili muscles: connected to hair follicle to raise or. Arrector pili muscles: connected to hair follicle to raise or lower hair. Sweat gland: produce water to keep cool (lost in some mammals) Secondary loss of hair: insulation by blubber instead. Membrane structure to separate the chest cavity and the stomach. Moves up and down to expand and contract chest cavity to breathe. Herbivore: lost upper incisors and canines, large premolars and molars. Allows more precise chewing and strengthens jaw. Mammary glands: produce milk to feed babies. Nipples evolve later (not found in monotremes) Mammary glands, no nipples, baby laps milk from hair. Cloaca: single opening for urogenital and digestive system.
