BIOL2712 Study Guide - Final Guide: Incus, Pit Viper, Semicircular Canals
25 Jun 2018
School
Department
Course
Professor
Control and Sensory Systems
Outline
Mode of action of sensory receptors
Types of sensory receptors
oMechanical
oChemical
oTemperature
oPain
oElectromagnetic
Visual receptors
oSimple and compound eyes
oSingle lens eyes
Hearing and balance
oInvertebrates vs. vertebrates
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Endocrine System
Excretes chemical messages = hormones
oInto surrounding fluid/circulation
Site of action is remote
All cells receive signal
Only target cells have receptors
Slow response
oMinutes – hours
Nervous System
Excretes chemical messengers = transmitters
oInto synapse
Between cells
Site of action is highly localized
Only adjacent cell receives signal
Very rapid response (milliseconds)
Functions of the Nervous System
Functions of the Nervous System
Nervous system transmits and processes information
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1. Sensory receptor (e.g. eye) receives input
2. Stimulus passed to brain and spinal cord via peripheral nervous system
3. Information integrated and processed by the brain and spinal cord
a. Central nervous system (CNS)
4. Response sent to effector (e.g. muscle block) by peripheral nervous system
Structure of Nervous System
Comprises of cells – neurons
oSpecialized to transmit signals from one location to another
oVery variable, but basic features common
Cell body
Dendrites conduct messages from tips toward cell body
One axon conducts messages from cell body to tips
Message sent unidirectionally
Mode of Action of Sensory Receptors
Neurons and sensory cells are “excitable”
Receipt of sensory stimulus
oOpens ion channels on sensory cell membrane
oChange in polarity
oReceptor potential
Depolarization or hyperpolarization of sensory neuron membrane
Depolarization = positive sodium ions raise the charge inside
the cell
Hyperpolarization = change in cell’s membrane potential,
making it more negative
Channels of Communication
How the signal is transmitted from sender to receiver
oTouch
oSmell
oTaste
oVision
oSound
Different channels have costs and benefits
oDepending on the environment and the information being transmitted
Channel Pros Cons
Touch Fast Need contact
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Document Summary
Types of sensory receptors: mechanical, chemical, temperature, pain, electromagnetic. Visual receptors: simple and compound eyes, single lens eyes. Excretes chemical messages = hormones: into surrounding fluid/circulation. Excretes chemical messengers = transmitters: into synapse. Nervous system transmits and processes information: sensory receptor (e. g. eye) receives input, stimulus passed to brain and spinal cord via peripheral nervous system. Information integrated and processed by the brain and spinal cord: central nervous system (cns, response sent to effector (e. g. muscle block) by peripheral nervous system. Comprises of cells neurons: specialized to transmit signals from one location to another, very variable, but basic features common. Dendrites conduct messages from tips toward cell body. One axon conducts messages from cell body to tips. Receipt of sensory stimulus: opens ion channels on sensory cell membrane, change in polarity, receptor potential. Depolarization or hyperpolarization of sensory neuron membrane. Depolarization = positive sodium ions raise the charge inside the cell.
