Chapter 45- Sensory Systems Flashcards
1
Q
Sensory Receptors overview
A
provide information from internal and external environments
2
Q
exteroceptors
A
sense external stimuli
3
Q
interoceptors
A
sense internal stimuli
4
Q
3 classes of Receptors
A
- mechanoreceptors
- chemoreceptors
- electromagnetic receptors
5
Q
Mechanoreceptors
A
stimulated by mechanical forces such as pressure
- receptors in skin
- respond to stimuli at border btwn internal and external envir.
6
Q
Chemoreceptors
A
detect chemicals or chemical changes
-ex. smell, taste
7
Q
Electromagnetic receptors
A
react to heat and light energy
-ie. vision, heat
8
Q
4 step process of CNS perceivance
A
- Stimulation-of sensory receptor cells
- transduction-in sensory receptor cells
- Transmission-along one or more sensory neurons
- interpretation-in CNS
9
Q
Receptor potential
A
- sensory cells respond to stimuli via stimulus-gated ion channels in membrane
- if stimulus is of sufficient magnitude, a depolarization of the receptor cell occurs
10
Q
Nociceptors
A
- mechanoreceptor
- transmit impulses perceived as pain
- most consist of free nerve endings located throughout body, especially surface
11
Q
Thermoreceptors
A
- mechanoreceptor
- naked dendritic endings of sensory neurons that are sensitive to changes in temp.
- cold receptors located higher in skin
12
Q
2 types of mechanoreceptors that respond to touch
A
- phasic-intermittently activated, hair follicles
- tonic-continuously activated
13
Q
Proprioreceptors
A
- monitor muscle length and tension
- provide info about relative position or movement of animals body parts
14
Q
Baroreceptors
A
- monitor blood pressure
- located at carotid sinus and aortic arch
- detect tension or stretch in the walls of these blood vessels
- when blood pressure decreases the frequency of barometric impulses decreases
15
Q
Hearing (what is it)
A
- detection of soundwaves
- sound is the result of vibration traveling through a medium
- detection is possible through action of specialized mechanoreceptors in inner ear
16
Q
lateral line system in fish
A
- consists of hair cells within longitudinal canal in the fishs skin
- hair cells are innervated by sensory neurons that transmit impulses to brain
17
Q
How does vertebrate hearing occur
A
- tympanic membrane vibrates causing movement in malleus, incus, and stapes
- stapes vibrates against oval window
- pressure waves vibrate through cochlea
- depolarizes hair cells which send action potentials to brain
18
Q
Echolocation
A
- mammals that can perceive presence and distance of objects by sound
- bats, shrews, whales, dolphins
19
Q
Statocyst
A
invertebrates use this to orient themselves with respect to gravity
20
Q
Utricle and Saccule
A
gravity receptors in vertebrates consisting of two chambers (as mentioned) in the membranous labyrinth
- utricle is more sensitive to horizontal acceleration
- saccule is more sensitive to vertical acceleration
21
Q
Vestibular Apparatus
A
- saccule, utricle and semicircular canals
- together they detect gravity changes
22
Q
Chemoreceptors
A
- bind to particular chemicals in the extracellular fluid
- membrane of sensory neuron becomes depolarized and produces action potentials
- used in the senses of taste and smell
- important in monitoring chemical composition of blood
23
Q
Gustation
A
- Taste
- mixture of physical and psychological factors
- taste buds are collections of chemosensitive cells associated with afferent neurons
24
Q
5 categories of taste
A
- sweet
- sour
- salty
- bitter
- umami (hearty)
25
Olfaction
- involves neurons located in upper portion of nasal passages
- receptors project into nasal mucosa, and their axons project directly into the cerebral cortex
- particles must first dissolve into extracellular fluid before they can activate the olfactory receptors
26
Vision
- begins with capture of light by photoreceptors
| - used to determine both direction and distance of object
27
Flatworm eyes
-can perceive direction of light but no visual image
28
what 4 phyla have well developed image forming eyes
- annelids
- mollusks
- arthropods
- chordates
29
Sclera
white portion of the eye, formed of tough connective tissue
30
Cornea
-transparent portion through which light enters, begins to focus light
31
Iris
colored portion of the eye
| -contraction of the iris muscles in bright light decreases the size of its opening, the pupil
32
Lens
transparent structure that completes focusing of light onto the retina
33
Near vs. Far vision
- lens is attached to ciliary muscles, changes shape of lens
- near vision=ciliary muscles contract-more bending of light
- far vision=ciliary muscles relax-less light bending
34
Rods
- on retina
| - responsible for black and white vision when illumination is dim
35
Cones
- on retina
- responsible for color vision and high visual acuity
- momst are located in central region of retina known as focea
36
Basic structure of rods and cones
- inner segment rich in mitochondria and vesicles filled with neurotransmitter molecules
- packed with hundreds of flattened disks which contain photopigments
37
Photopigment in rods
rhodopsin
38
Photopigment in cones
photopsins
| -3 kinds of cones
39
3 layers of retina
1. external layer contains rods and cones
2. middle layer contain bipolar cells
3. layer closest to eye cavity contains ganglion cells
- -photoreceptors activate bipolar cells which activate ganglion cells which transmit impulses to brain via optic nerve
40
What happens to eyes in the dark
- photoreceptor cells release an inhibitory neurotransmitter that hyperpolarizes the bipolar neurons
- prevents the bipolar neurons from releasing excitatory neurotransmitter to the ganglion cells that signal to the brain
41
What happens to eyes in the light
- photoreceptor cells stop releasing their inhibitory neurotransmitter, in efect, stimulating bipolar cells
- bipolar cells in turn stimulate the ganglion cells, which transmit action potentials to the brain
42
Visual Processing
- action potentials in the optic nerves are relayed from the retina to the lateral geniculate nuclei of the thalamus
- then projected to the occipital lobes of cerebral cortex
43
Color blindness
- lack of one or more types of cones
- sex linked recessive trait
- people with normal vision are trichomats
44
Binocular vision
- primates and most predators have 3 eyes on each side of face
- 2 fields of vision overlap (binocular vision)
- prey have eyes on both sides of head
45
Detection of electrical currents
-elasmobranches (sharks, rays, skates) have electroreceptors called ampullae of lorenzini that sense electrical currents generated by muscle contractions of prey
46
Detection of Magnetic fields
-eels, sharks, bees and many birds appear to navigate along the magnetic field lines of earth
