BIOL 1175 Lecture Notes - Extracellular Fluid, Hypothalamus, Homeostasis
Document Summary
Dynamic equilibrium: three semicircular canals are perpendicular to one another, each canal is gelatinous mass called cupula in which hair cells are embedded, canals and chambers are filled with fluid that moves when head does. Movement of fluid pushes the cupula and stimulates hair cells that send message to the brain regarding body position and movement: brain interpret the signal and maintains our balance. Static equilibrium: vestibule consist of utricle and saccule, two fluid filled cavatiesi, utricle and the saccule contain hair cells overlaying gelatinous material. Embedding in the gelatinous material are granules of calcium carbonate called otliths: when head is tilted, otooliths in gelatinious material side downhill over the hair cells, stimulating them. Hair cells send signal to brain: brain interprets signal to know the position of head. Mostly comprised of glands that contain secretory cells that release their products, called hormones, into extracellular fluid where they diffuse into the bloodstream.
