AP Mechanoreception - Animal Physiology Mechanoreception...

This preview shows page 1 - 3 out of 9 pages.

Animal Physiology Mechanoreception Mechanoreceptor Ion Channels - Two types of mechanoreceptor proteins: o ENaCs (epithelial sodium channels) o TRP (transient receptor potential channels Stretch activated ion channels with two attachment points Extracellular matrix proteins Cytoskeleton - Mechanical forces cause displacement of extracellular anchoring proteins resulting in conformational change - Absence of intracellular cascade (mechanoreceptors are ion channels connected to cytoskeleton) - Similar sensory transduction in inverts and vertebrates - Location and/or peripheral filtering mechanisms determine whether activated by sound, gravity, acceleration, or water currents. - Figure 6.12: Mechanosensory protein complexes o Drosophila touch receptors contain mecahnosensory neurons with TRP-type channels in their membranes. o Mechanical stimuli cause the extracellular anchors to move relative to the cytoskeleton, pulling on the channel and causing a conformational change that opens or closes the channel, changing the membrane potential of the cell. Types of mechanoreceptors - Touch and Pressure o Baroreceptors (vertebrates) o Tactile receptors (vertebrates and inverts) o Proprioceptors (verts and inverts) - Equilibrium and Hearing (verts and inverts) o Statocysts o Hair cells o Neuromasts o Electroreceptors Touch and Pressure Baroreceptors (verts) - Detect pressure changes in wall of blood vessels, parts of the heart, digestive, reproductive and urinary tracts - E.g. Carotid sinus baroreceptors: monitor blood pressure to the brain. - When it stretches it sends a message. Found anywhere in the body that needs to know what is going on. - The baroreceptors help our body figure out what is in its pipes.
Tactile Receptors (verts) - Detect touch pressure vibration on the body o Tonic receptor cells. o Detect light touch and pressure on the skin surface. - Free nerve endings o Sensory neurons with dendrites interspersed among epidermal cells o Receptor proteins on the dendrites - Merkel’s Disk: o Enlarged epidermal cell (Merkel cells) associated with free nerve endings. o Small receptive field (fine discrimination) - Phasic receptor cells; detect movement or pressure on skin surface - Root Hair plexus: o Nerve endings wrap around base of hair follicles (respond when hair displaced) o Phasic receptors o Detect changes in movement across the body surface - Pacinian Corpuscle o Sensory dendrite surrounded by lamellae o Located in skin (deep), muscles, joints, and internal organs o Phasic receptors, detect changes in pressure o Large receptive field, poor discrimination, especially sensitive to vibration, - Ruffini Corpuscle o Dendrite endings with elongated capsule o Located in connective tissue of the skin and movement of joints o Help detect position of body in space (proprioceptor) Tactile Receptors (inverts) - What do you do when you have a cuticle?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture