Chapter 41: Sensory Systems Flashcards
What is echolocation?
bats use this to see in the dark. They send out sound waves and then the waves bounce off objects and the bats can then put together a picture of their surroundings.
gives them secondary vision
What is a stimulus?
a change in the internal or external environment that can be detected by the organism’s body
What detects a stimulus?
sensory receptors
What are the 5 basic types of receptors?
mechanoreceptors, photoreceptors, chemoreceptors, thermoreceptors, nociceptors
What is a mechanoreceptors? ex? found in?
Detect mechanical energy when it deforms membranes, physical movement of receptor
ex) auditory receptors in the ears
found in skin, skeletal muscles, walls of blood vessels, and internal organs
What is a photoreceptors? ex?
detect the energy of light
ex) found in retina of eye
What is a chemoreceptors? ex?
detect specific molecules or chemical conditions (acidity)
ex) taste buds on the tongue
What is a thermoreceptors? ex?
detect the flow of heat energy
ex) temperature receptors in the skin
What is a nociceptors? ex?
detect tissue damage or noxious chemicals, register their activity as pain
ex) pain receptors are located in the skin and in some internal organs
What is a receptive field?
a region in which the receptor responds to a stimulus
What are some of the disadvantages of free nerve endings?
they are not as sensitive b/c stimulus has to hit the free nerve exactly
a nerve “pad” increases the receptor field which increases sensitivity
What is signal transduction?
conversion of a stimulus into a receptor potential
What do photons use for communication?
they use transduction, they are not neurotransmitters
What are the 2 ways intensity of a stimulus are registered?
1) frequency of action potentials
2) number and types of afferent neurons that the stimulus activates to generate action potentials in the pathway
What is sensory adaptation?
the frequency of action potentials generated in afferent neurons is reduced when the intensity of a stimulus remains constant
increases the sensitivity of receptor systems to changes in environmental stimuli, which may be more important to survival than constant factors
How does perceptions differ from reality?
- Lack receptors for some types of energy (e.g., X-rays)
* Sensory input is processed in various ways
How does a mechanical stimulus work?
creates tension in the plasma membrane of a receptor which causes ion channels to open, producing a receptor potential
What are the types of receptors for touch and pressure human skin has?
free nerve endings, Pacinian corpuscles, Ruffini endings, and Meissner’s corpuscles
What do free nerve endings respond to?
light touch
What do pacinian corpuscles respond to?
deep pressure and vibrations—- warning signals
What do ruffini endings respond to?
deep pressure
What do meissner’s corpuscles respond to?
light touch and surface vibrations
What are proprioceptors
a mechanoreceptor that detect stimuli used in the CNS to maintain body balance and equilibrium and to monitor the position of the head and limbs
What are muscle spindles?
bundles of specialized muscle cells wrapped with the dendrites of afferent neurons
cerebellum uses this info