Chapt 49 - CHAPTER 49 SENSORY AND MOTOR MECHANISMS A Sensing Acting and Brains 1 The brains processing of sensory input and motor output is

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER 49 - SENSORY AND MOTOR MECHANISMS A. Sensing, Acting, and Brains 1. The brain’s processing of sensory input and motor output is cyclical rather than linear The way it ISN’T: sensing brain analysis action. The way it is: sensing, analysis, and action are ongoing and overlapping processes. Sensations begin as different forms of energy that are detected by sensory receptors. This energy is converted to action potentials that travel to appropriate regions of the brain. The limbic region plays a major role in determining the importance of a particular sensory input. B. Introduction To Sensory Reception Sensations are action potentials that reach the brain via sensory neurons. Perception is the awareness and interpretation of the sensation. 1. Sensory receptors transduce stimulus energy and transmit signals to the nervous system Sensory reception begins with the detection of stimulus energy by sensory receptors . Exteroreceptors detect stimuli originating outside the body. Interoreceptors detect stimuli originating inside the body. Sensory receptors convey the energy of stimuli into membrane potentials and the transmit signals to the nervous system. This involves: sensory transduction, amplification, transmission, and integration. Sensory Transduction . The conversion of stimulus energy into a change in membrane potential. Receptor potential Amplification . The strengthening of stimulus energy that is can be detected by the nervous system. May be a part of, or occur apart from, sensory transduction. Transmission. The conduction of sensory impulses to the CNS. Some sensory receptors must transmit chemical signals to sensory neurons. The strength of the stimulus and receptor potential affects the amount of neurotransmitter released by the sensory receptor. Some sensory receptors are sensory neurons. The intensity of the receptor potential affects the frequency of action potentials. Integration . The processing of sensory information. Begins at the sensory receptor. For example, sensory adaptation is a decrease in responsiveness to continued stimulation. For example, the sensitivity of a receptor to a stimulus will vary with environmental conditions.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2. Sensory receptors are categorized by the type of energy they transduce Mechanoreceptors respond to mechanical energy. For example, muscle spindles are an interoreceptor that responds to the stretching of skeletal muscle. For example, hair cells detect motion. Pain receptors = nocioceptors . Different types of pain receptors respond to different types of pain. Prostaglandins increase pain by decreasing a pain receptors threshold.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/14/2009 for the course BIOCHEM bIO taught by Professor Professor during the Spring '09 term at École Normale Supérieure.

Page1 / 8

Chapt 49 - CHAPTER 49 SENSORY AND MOTOR MECHANISMS A Sensing Acting and Brains 1 The brains processing of sensory input and motor output is

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online