chapter 7 - sensory systems

what type of senses are provided by the action of mechanoreceptors

what type of senses are provided by the action of mechanoreceptors

touch and pressure

hearing and equilibrium

what are the 3 types of touch and pressure receptors

baroreceptors, tactile receptors, proprioceptors

baroreceptors detect…

internal pressure change

tactile receptors detect…

external touch, pressure, vibration

proprioceptors monitor…

body position to provide sensory input for balance and control for body movements

vertebrate tactile receptors are widely dispersed in the…

skin

vertebrate tactile receptors in the skin include… (2)

free nerve endings and nerve endings enclosed in accessory structures

name two types of insect tactile receptors

trichoid sensilla and campaniform sensilla

name 3 types of vertebrate proprioceptors

muscle spindles, golgi tendon organs, joint capsule receptors

muscle spindles monitor…

skeletal muscle length

muscle spindles monitor skeletal muscle length in order to prevent…

excessive movement at joints

golgi tendon organs monitor…

tendon tension

golgi tendon organs monitor tendon tension to prevent…

excessive muscle contraction

joint capsule receptors monitor…

pressure, tension, and movement

joint capsule receptors provide …

sensory input for balance

what is the insect proprioceptor known as

scolopidia

what is the role of scolopidia in some species

modified into tympanal organs sound detection

in vertebrate what is responsible for balance and hearing

ears

in invertebrates … organs are used for hearing and balance

different

what specifically allows fish and amphibians to detect body positive and movement

hair cells

what are hair cells

modified epithelia cells

two key structures of hair cells

kinocilium (true cilium) and stereocilia (microvilli)

movement of … changes ion permeability

steorcilia

direction and degree of sterocilia bending affects…

number of open K+ and Ca+ channels → amount of neurotransmitter release → frequency of AP produced

what organ helps detect invertebrate equilibrium

statocysts

what are statocysts

hollow, fluid-filled cavities lined with mechanoreceptors

what do statocysts contain

statoliths

statoliths stimulate what

mechanoreceptors

three important organs for invertebrate hearing

trichoid sensilla, chordotonal organs, tympanal organs

name two important structures in fish and amphibians ability to detect body position and movement

neuromast and lateral line system

what is the neuromast

hair cell stereocilia embedded in cupola, detect water movement

what is the lateral line system

linear arrays of neuromasts in skin on sides of body and head

what are the three components of the ear in vertebrates

outer ear, middle ear, inner ear

what makes up the outer ear

pinna and auditory canal

what makes up the middle ear

interconnected bones in air filled cavity

what makes up the inner ear

fluid-filled sacs and canals

location of hair cells

the inner ear is important for detecting …

movement for balance

what are the components of the inner ear which are important for detecting movement for balance e

3 semi-circular canals w/ enlarged ampulla and 2 swellings (utricle and saccule)

3 semi-circular canals w/ enlarged ampulla detect…

rotational movements

utricle and saccule detect …

linear movements and head tilting

what is improtant for hearing in birds and mammals

lagena, extension of saccule forms cochlea with hair cells

macula detects…

horizontal and vertical linear movements and tilting of head

macula is found in …

utricle and saccule

cristae has hair cells in…. (2)

capula and ampullae of semicircular canals

cristae detect…

angular acceleration

frequency detection happens through

different areas of membrane stimulated, and high frequency stimulates at cochlea base while low frequency stimulates apex

amplitude detection happens through

loud sounds causing larger movements of basilar membrane, increase in depolarization of hair cells → increase action potential frequency

what are the two basic types of photoreceptors

ciliary and rhabdomeric

ciliary is a ….

single, highly folded cilium

rhabdomeric’s surface has …

microvillar projections

what two types of photoreceptors are found in vertebrates

rods and cones

how do photopigments produce photo-transduction

chromophore absorbs photo energy → dissociates with opsin → activates G-protein → causes formation of 2nd messenger → ion channels open/close → change membrane potential to stimulate or inhibit NT release

vertebrate retina have several types of neurons

horizontal, bipolar, amacrine

these neurons in the vertebrate retina are all involved in processing…

visual signals from rods and cones to the ganglion cells of the optic nerve

do rods exhibit convergence

yes

many rods synapse with one…

bipolar cell

many bipolar cells synapse with one…

ganglion cells

each ganglion cell has a … receptive field

large

convergence in rods provides…

low resolution and high sensitivity

do cones exhibit convergence

no

each cone synapse with one…, bipolar cell synapses with one…

bipolar cell, ganglion cell

each ganglion cell has … receptive field

small

cones provide … resolution but … sensitivity

high, poor

what allows for color vision in vertberates

detection of different wavelengths from different types of cones

most mammals are …. which means they have .. cone types

dichromatic, 2

humans are … which means they have … cone types

trichromatic, 3

birds, reptiles, and fish are either …, … or ….

tri-, tetra-, or pentachromatic

mantis shrimp are… which means they have … cone types

dodecachromatic, 12

accommodation is the process by which an…

eye changes its focal length

accommodation allows the eye to produce a …

focused image of objects at different distances

polychaete worms change their focal length by changing the …. , which alters the size of the eye and thus the distance between the lens and the retina (accommodation)

volume of liquid in the eye

invertebrates and vertebrates alter focal length by …(accommodation)

moving the lens and the retina

lizards, birds, and mammals alter their focal length by changing the …. (accommodation)

shape of the lens

to focus on nearby objects, the ciliary muscles …, which … the width and … the tension on the suspensory ligament, causing the lens to become more rounded

contract, increases, loosens

to focus on distant objects, the ciliary muscles…, this … the width of the ciliary muscles, … the tension of the suspensory ligaments, which pulls on the lens and flattens it

relax, reduces, increasing

what are the two types of receptors for temperature

central thermoreceptors and peripheral thermoreceptors

central thermoreceptors are found in the … and monitor …

hypothalamus, core internal temperature

peripheral thermoreceptors are found on the … and monitor …

skin, environmental temperature

what are the two types of peripheral receptors

warm sensitive and cold sensitive

what receptors are useful for painfully hot stimuli

thermal nociceptors

what do pit vipers and bird snakes use to detect heat radiating objects

pit organs

pit organs can detect …. degrees C changes (humans can only detect 0.5 degree C changes)

0.003

what type of animals have magneto-sensory neurons

nematodes

what type of animals use Earth’s magnetic field to help them navigate (2)

migratory birds and homing salmon

sea turtles have magnetite in … around the brain

dura mater

in the retina of some vertebrates they have ….

crypto-chrome

what are the Ampullae of Lorenzini

a series of pits found on the noses of sharks and rays acting as poly-modal receptors that detect both electrical and mechanical stimuli

what type of animals have Ampullae of Lorenzini

shark and rays

platypus “bill” has both … and …

electroreceptors and mechanoreceptors