A&p Chapter 15

Front 1

Sensory receptors

Back 1

specializedcells that monitor specific conditions in the body or external environment.Detects an arriving stimulus and translates it into an action potential thatcan be conducted to the CNS. The process is called transduction.

Front 2

General senses

Back 2

Temperature, pain, touch, pressure, vibration,and proprioception.

Front 3

Special senses

Back 3

Smell(olfaction), taste (gustation), sight (vision), hearing, equilibrium (balance),and hearing

Front 4

Specialsense organs

Back 4

where special sensory receptors are located eg. eye and ear.Information the receptors provide is distributed to specific areas of cerebralcortex eg. auditory cortex and visual cortex.

Front 5

Receptive field

Back 5

Area monitored by a single receptor. Larger thereceptive field, the poorer your ability to localize a stimulus. eg. painreceptors. They are hard to localize.· Different forms of stimulus, example physicalforce (pressure), dissolved chemical, sound, and light. Regardless of thenature of the stimulus, sensory information is sent to the CNS in the form ofaction potentials.

Front 6

Tonic receptors

Back 6

somesensory neurons are always active.

Front 7

Phasic receptors

Back 7

Receptors are normally inactive, but becomeactive for a short time for a short time whenever a change occurs. eg.temperature receptors.

Front 8

Adaptation

Back 8

Reducesensitivity in the presence of a constant stimulus. eg. when you stop noticingthe background noise of an air conditioner.

Front 9

Fast-adapting receptors

Back 9

Examples of phasic receptors. Temp.- you don’tnotice room temp. changes unless it suddenly drops.

Front 10

Slow-adapting receptors

Back 10

Examples of tonic receptors. Pain.- takes you along time to adjust to pain.· Exteroceptors:receive outside information

Front 11

Proprioceptors

Back 11

Report the positions of skeletal muscle andjoints;

Front 12

Interoceptors

Back 12

Monitor visceral organs and functions

Front 13

Interoceptors are divided into?

Back 13

•Nociceptors

•Thermoreceptors

•Tactilereceptors

•Baroreceptors

Front 14

Nociceptors

Back 14

-PainReceptors

Common in:

•Inthe superficial portions of the skin

•Injoint capsules

•Withinthe periostea of bones

•Aroundthe walls of blood vessels

•Maybe sensitive to:

1.Temperatureextremes

2.Mechanicaldamage

3.Dissolvedchemicals, such as chemicals

released by injured cells

•Arefree nerve endings with large receptive fields.

•Branchingtips of dendrites

•Notprotected by accessory structures •Canbe stimulated by many different stimuli

•Twotypes of axons - Type A and Type C fibers

Front 15

Nociceptors Type A

Back 15

•MyelinatedType A fibers

•Carrysensations of fast pain, or pricklingpain,such as that caused by an injection or a deep cut

•Sensationsreachthe CNS quickly and often trigger somatic reflexes

•Relayedto the primary sensory cortex and receive conscious attention

Front 16

Nociceptors Type C

Back 16

•TypeC fibers

•Carrysensations of slow pain, or burning and aching pain

•Causea generalized activation of the reticular formation and thalamus

•Youbecome aware of the pain but only have a general idea of the area affected

Front 17

Thermoreceptors

Back 17

•Alsocalled temperature receptors

•Arefree nerve endings located in:

•Thedermis

•Skeletalmuscles

•Theliver

•Thehypothalamus

Front 18

Thermoreceptors Temperature sensations

Back 18

Conducted along the same pathways that carry pain sensations

Sent to:

The reticular formation

The thalamus

The primary sensory cortex (to a lesser extent)

Front 19

Mechanoreceptors

Back 19

•Sensitiveto stimuli that distort their plasma membranes

•Containmechanically gated ion channelswhose gates open or close in response to:

•Stretching

•Compression

•Twisting

•Otherdistortions of the membraneC

Front 20

Classes of Mechanoreceptors are

Back 20

1.Tactilereceptors

·Finetouch & pressure receptors: provide detailed information about sourceof stimulation; extremely sensitive; have narrow receptive fields.

·Crudetouch & pressure receptors: provide poor localization and littledetails of stimulation; have large receptive fields.

·Six typesof tactile receptors: free nerve endings, root hair plexus, tactile discs(Merkel), tactile corpuscles (Meissner’s), lamellated (Pacinian) corpuscles,and Ruffini corpuscles.

2.Baroreceptors

•Detectpressure changes in the walls of blood vessels and in portions of the digestive, reproductive, and urinary tracts

3.Proprioceptors

•Monitorthe positions of joints and muscle

•Themost structurally and functionally complex of general sensory receptors