What are the strength and direction of the magnetic field at the center of the loop in FIGURE P29.43?
4/19/2016 The Special Senses are thesenses that have specialized organs devoted to them: vision (the eye) hearing and balance (the ear, which includes the auditory system and vestibular system) smell (the nose) taste (the tongue) Vision The Eye Fibrous Tunic area outside of the eye 1. Sclera the white of the eye is in the posterior ⅚ of eye 2. Cornea clear part of eye is in anterior ⅙ of eye Vascular Tunic heavily pigmented tunic that prevents light scattering within the eye. Parts: 1. Choroid blood vessels. Dark posterior ⅚ of eye 2. Ciliary Body Smooth muscles: suspensory ligaments, lens Ciliary Process 3. Iris Muscular diaphragm Controls amount of light that lets in Gets bigger and smaller Posterior Segment: comprises most of the eye vitreous humor gel→ shapes eye. Anterior Segment: anterior chamber and a posterior chamber. Anterior chamber is anterior to iris, posterior chamber is posterior to the iris. Filled with aqueous humor. Ciliary Process→ Posterior Chamber→ Anterior Chamber→ Scleral Sinus *Glaucoma condition where there is increased pressure on the eye Retina 1. Pigmented layer 2. Nervous tissue layer Photoreceptors Bipolar cells Ganglion cells Photoreceptors 1. Cones 3 types: Red, Green, Blue a. Found in high light levels b. Located in fovea centralis macula c. Wiring: more one to one with bipolar cells than rods 2. Rods Black and white a. Work best in low light levels b. Periphery Optic Disk Aka blind spot Where ganglion cells are exiting the eye Some Vocab: Refraction: bending of light one substance to another Accommodation: change in curvature of the lens for close up vision Myopia: near sighted Hyperopia: farsighted Eyelid: contains tarsal glands. Secrete oily substances, cysts form when infected. Eyelash: sebaceous glands. Sty formed when infected. Conjunctiva: mucous membrane, conjunctivitis occurs when infected. Lacrimal glands produces tears, consists of: Lacrimal canal Lacrimal sac Nasolacrimal duct Photoreceptors Outer segment of photoreceptor embedded in pigmented layer Disc Membrane proteins opsins 3 opsins in cones 1 opsin in rods Rhodopsin (in rods) Opsincisretinal: in the presence of light, also there are high levels of GMP present. Aka bleaching→ Opsin + all trans retinal increase cGMP breakdown, low GMP present. Dark: 1. cGMP will open Na and Ca ion channels. This will cause photoreceptors to depolarize. 2. Voltage gated Ca ion channels open 3. This releases a neurotransmitter/ an inhibitory neurotransmitter 4. Causes inhibitory postsynaptic potential in bipolar cells→ hyperpolarized 5. Hyperpolarized 6. So, no neurotransmitter is released Hearing and Balance The Ear Outer, Middle, and Inner Ear Outer Ear Pinna: collects sound External auditory canal contains ceruminous glands (which has cerumen earwax) Middle Ear Air filled Tympanic membrane eardrum Connected to malleus (hammer), incus (anvil), and stapes (stirrup) Synovial joints connect the malleus, incus, and stapes. Inner Ear Fluid filled Cochleahearing Semicircular canals dynamic balance Vestibule static balance Oval window stapes Round window Osseous Labyrinth little canals and tubes Inside there is a membranous labyrinth Endolymph is the term for inside of membranous Perilymph is the erm for outside of membranous Spiral organ of corti Hair cells Tectorial membrane Sound Pitch: frequency of sound waves Loudness: magnitude of sound waves High pitch is at the base of the cochlea Low pitch is at the apex of cochlea Static Balance: vestibule Giving info concerning the position of the head Maculae: receptor organ, hair cells Otolithic membrane: otolith ear stone Dynamic Balance: semicircular canal Crista hair cells Cupula gel like substance Smell The Nose Detects chemicals in the air Receptors (dendrites) embedded in mucus Chemical dissolve mucus Bind to receptors (ion channels) About 500 receptors that bind to 500 different molecules We can detect 10,000 different smells