A & P 2 - Class 2 - Sensation & Perception

Question 2

Explain what changes in the environment means.

Answer 2

The entire nervous system is basically the body’s way of detecting and responding to “changes in the environment” both internal and external. A good starting point is therefore “changes in the environment”. Change in the environment=STIMULUS.

Question 3

Define sensation

Answer 3

Subconscious or conscious registration of a stimulus in the central nervous system (CNS).

Question 4

Define perception.

Answer 4

Conscious awareness of a sensation.

Question 5

List the steps in the “Process of Sensation”.

Answer 5

Stimulus, sensory receptors, sensory neurons, action potentials.

Question 6

Sensory receptors detect what?

Answer 6

Internal and external stimuli and they vary in how quickly they adapt to changes in the environment.

Question 7

Sensory neurons do what?

Answer 7

Generate nerve impulses (action potentials).

Question 8

Action potentials do what?

Answer 8

Travel along a sensory neuron and stimulate neurons in the CNS.

Question 9

Perception occurs when?

Answer 9

If the CNS is stimulated at the conscious level - the “highest” outermost part of the brain (cerebral cortex).

Question 10

Define adaption.

Answer 10

Many receptors become less sensitive to a stimulus that is continuously present.

Question 11

Explain about tactile and smell receptors.

Answer 11

They are rapidly adapting receptors. Sensitive to CHANGE rather that continuous output.

Question 12

Explain about nociceptors and proprioceptors.

Answer 12

They are slowly adapting receptors. Continue to trigger nerve impulses as long as the stimulus persists.

Question 13

What is “phantom limb” sensation?

Answer 13

People with an amputated limb may still experience sensations as if the limb were still there.

Question 14

What are two explanations for what causes “phantom limb”?

Answer 14

Impulses from sensory neurons in the stump enter the CNS: the brain projects the sensation (and perception) back to the nonexistent limb creating the felt sensory perception of a limborNeurons in the brain that generate the felt sense continue to be active, with or without input from the stump.

Question 15

What is perception?

Answer 15

Stimuli that are perceived in the higher brain centers are projected back to the receptor by the brain.

Question 16

Sensory receptors can be classified into what three categories?

Answer 16

By location, by cellular characteristics, and by stimulus.

Question 17

Explain receptor/neuron specialization.

Answer 17

Each receptor responds to a particular type of stimulus. Each neuron conducts an impulse that has a particular function.

Question 18

What are the three types of receptors that are found by location?

Answer 18

Exteroceptors, proprioceptors, interoceptors.

Question 19

Explain exteroceptors.

Answer 19

They are cutaneous receptors located on or very near the surface (skin and superficial fascia) and usually respond to external stimuli.

Question 20

Explain propriocepters.

Answer 20

Located in skeletal muscle, joint capsules, tendons, and fascia. Monitor stretch and tension - mechanical tugs on our tissues. Provide info about our physical orientation and movement.

Question 21

Explain interoceptors.

Answer 21

Also called visceroceptors or enteroceptors that are located internally, often within viscera (organs). They respond to internal stimuli.

Question 22

What two types of receptors are classified by cellular characteristics (physical structure)?

Answer 22

Simple and complex receptors.

Question 23

What are the two types of nerve endings found in simple receptors?

Answer 23

Free nerve endings and encapsulated nerve endings.

Question 24

Free nerve endings dendrites do what?

Answer 24

Dendrites respond directly to stimulus. Examples include nociceptors (pain receptors).

Question 25

Encapsulated nerve endings dendrites are wrapped in what?

Answer 25

Dendrites wrapped in a connective tissue coating. Examples include various types of mechanorecptors and corpuscles.

Question 26

Explain complex receptors (cellular receptors).

Answer 26

Entires cells that detect stimuli and initiate sensory impulses. Associated with special senses (sight, smell, taste, hearing, and balance).

Question 27

List the classification of sensory receptors by stimulus.

Answer 27

Mechanoreceptors, thermoreceptors, nociceptors, photoreceptors, and chemoreceptors.

Question 28

Mechanoreceptors do what?

Answer 28

Respond to chemical deformation of tissue (pressure, etc.)

Question 29

Thermoreceptors do what?

Answer 29

Respond to temperature.

Question 30

Nociceptors do what?

Answer 30

Respond to pain (actual or near damage to tissue).

Question 31

Photoreceptors do what?

Answer 31

Respond to visible light.

Question 32

Chemoreceptors do what?

Answer 32

Respond to chemicals (smell, taste or internal).

Question 33

What are the types of sensations?

Answer 33

General, visceral, somatic, cutaneous, and special.

Question 34

What are general senses?

Answer 34

Sensed body-wide, simple receptors, include touch, pressure, vibration, pain, temperature, and proprioception.

Question 35

Visceral sense do what?

Answer 35

They provide information about conditions within internal organs.

Question 36

Somatic senses do what?

Answer 36

Include the cutaneous sensations PLUS proprioceptions - arise from the skin, muscles, joints, and fascia.

Question 37

Cutaneous senses do what?

Answer 37

Arise from the skin AND subq tissue.

Question 38

What are the three subcategories of the cutaneous senses?

Answer 38

Tactile-require contact.Thermal-temperature related (skin and deeper).Pain-from the surface to the deep fascia.

Question 39

Name the five special senses.

Answer 39

Smell, taste, vision, hearing, and balance.