Ch 50 - Sensory and Motor Mechanisms (1 slide per page)

Action potential in presynaptic neuron causes

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Unformatted text preview: al into muscle tissue 1. Action potential in presynaptic neuron causes neurotransmitter to bind to muscle cell 2. This initiates an action potential in the muscle cell which propagates down T-tubule (an infolding of plasma membrane) Refer to Figure 50.30 (Campbell 9 th ed) 13 Action potential causes Ca2+ release leading to muscle contraction 3. Voltage gated Ca2+ ion channels open in a muscle cell organelle (sarcoplasmic reticulum (SR), a kind of smooth endoplasmic reticulum). 4. Stored Ca2+ from SR flows into cytosol causing muscle to contract. 5. Ca2+ actively transported back into SR 6. As Ca2+ level drops, tropomyosin blocks myosin binding site and muscle relaxes. Refer to Figure 50.30 (Campbell 9th ed) 14 Sensation, Perception & Response Bats sense moths with sonar and respond by chasing prey. Moths sense bat and respond by evading predator. Both sense location, altitude, direction, velocity in self and other. IOW, they create a perception of the world around through various sensory inputs Both rely on complex sensory systems for survival! 19 Types of Sensory Receptors Mechano Chemo Electromagnetic 5 types: 1. Mechanoreceptors 2. Chemoreceptors 3. Electromagnetic receptors 4. Thermoreceptors 5. Pain receptors Thermo Pain 20 Types of Sensory Receptors Mechano Sense physical deformation caused by mechanical energy Respond to: pressure, stretch, motion, sound Types of mechanoreceptors: 1. Pressure 2. Stretch 3. Motion sensitive hairs 4. Membranes Detect substrate, air or fluid movements • Involved in numerous sensations including hearing 21 Types of Sensory Receptors Mechano Pressure receptors = stacks of cells with neuron dendrites between layers Occur in dermis Intensity may depend on: A. Which receptors/neurons are activated • Light pressure - close to surface • Strong pressure - in deeper layers B. Rate of action potentials • light = low frequency • strong =high frequency C. # of receptors activated Figures 50.4 and 50.5 (Campbell 9th ed.) 22 Types of Sensory Receptors Mechano Stretch receptors • Mechanoreceptors responsive to distention of various organs and muscles
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This note was uploaded on 02/12/2014 for the course BIOLOGY 2011 taught by Professor Woo during the Fall '10 term at University of Central Florida.

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