Chapter 50

Question 1

Four basic functions of sensory pathways

Answer 1

Sensory reception, transduction, transmission, and perception

Question 2

What is the central nervous system (CNS)?

Answer 2

It is where integration takes place, and it includes the brain and spinal cord

Question 3

What is the peripheral nervous system (PNS)?

Answer 3

It carries information into and out of the CNS and it includes the cranial nerves, and ganglia outside the CNA and spinal nerves

Question 4

Afferent division of the PNS

Answer 4

Transmits sensory information to the CNS ; neurons monitor condition inside and outside CNS

Question 5

Efferent division of the PNS

Answer 5

Carries commands from the CNS to the body ; neurons carry signals that allow for a response

Question 6

What are the five different categories of sensory receptors?

Answer 6

Mechanoreceptors, chemoreceptors, electromagnetic receptors, thermoreceptors, and pain receptors

Question 7

What do Mechanoreceptors do?

Answer 7

They sense physical deformation caused by forms of mechanical energy (pressure, touch, sound, etc.) ; consist of ion channels linked to structures that end outside of the cell ; the mammalian sense of touch relies on Mechanoreceptors that are dendrites of sensory neurons

Question 8

What do chemoreceptors do?

Answer 8

They sense chemical, and some of them transmit information about the total solute concentration of a solution while others respond to specific molecules in body fluids ; when a stimulus binds to this receptor, it becomes more or less permeable to ions

Question 9

What do electromagnetic receptors do?

Answer 9

They detect electromagnetic energy (light, electricity, magnetism)

Question 10

What is electroreception?

Answer 10

The biological ability to perceive natural electrical stimuli ; It has been observed almost exclusively in aquatic organisms

Question 11

What do thermoreceptors do?

Answer 11

They detect heat and cold ; mammals have a variety of thermoreceptors, each specific for a particular temperature range

Question 12

What do pain receptors do and what is another name for them?

Answer 12

Nociceptors ; they detect stimuli that reflect harmful conditions ; respond to extreme pressure or temp or chemicals released from damaged or inflamed tissues

Question 13

Capsaicin

Answer 13

What makes the pepper hot ; milk dissolved it because they are both nonpolar (water in polar) and that is why it is better to drink milk when you have something spicy

Question 14

What is sensory transduction?

Answer 14

The conversion of stimulus energy into a change in membrane potential of a sensory receptors

Question 15

What is receptor potential?

Answer 15

Change in membrane potential ; they are graded potentials so their magnitude varies with the strength of the stimulus

Question 16

What is sensory adaptation?

Answer 16

It is a decrease in responsiveness to continued stimulation, which enables the detection of changes in environments that vary in stimulus intensity

Question 17

What happens in transmission?

Answer 17

Sensory information travels through the nervous system as action potentials ; the size of the receptor potential increases with the intensity of the stimulus ; In sensory neurons that spontaneously generates action potentials at a low rate, a stimulus changes how often an action potential is produced

Question 18

What is perception?

Answer 18

It is the brain’s construction of stimuli

Question 19

How does perception work?

Answer 19

Stimuli from different sensory receptors travel as action potentials along dedicated neural pathways ; the brain distinguishes stimuli from different receptors based on the path by which the action potentials arrive ; activation of the “correct” sensory neuron varies for each of the senses

Question 20

In a general sense, how do we hear?

Answer 20

We hear because vibrating objects create pressure waves in the air

Question 21

What is sound?

Answer 21

Sound is a pressure wave ; when an object vibrates, it created mechanical disturbances in the medium which it is directly adjacent to and this medium carries the disturbance in the form of oscillation and propagating pressure waves

Question 22

Volume vs Pitch vs Frequency

Answer 22

Volume is the amplitude of the sound wave, pitch is the frequency of the sound wave, and frequency is the number of times the pattern is repeated per second (Hertz)

Question 23

What is a more detailed description of how we hear?

Answer 23

Moving air reaches the outer ear and causes vibration of the tympanic membrane ; the three bones of the middle eat transmit the vibrations to the oval window ; when the stapes (one of the 3) vibrates against the oval window, it created pressure waves in the fluid inside the cochlea ; fluid pressure waves push down cochlear duct and basilar membrane ; this membrane and the hair cells move up and down which depolarizes the membranes of Mechanoreceptors and sends action potentials to the brain via the auditory nerve

Question 24

How can the hear detect pitch?

Answer 24

The cochlea distinguishes pitch because the basilar membrane is not uniform along its length and each region is tuned to a particular vibration frequency

Question 25

What are the five taste perceptions?

Answer 25

Sweet, sour, salty, bitter, umami

Question 26

Taste buds

Answer 26

Located in several areas of the tongue and mouth ; any region with taste buds can detect any of the five types of taste ; most taste buds are associated with projections called papillae

Question 27

What are the neurons that line the upper portion of the nasal cavity?

Answer 27

Olfactory receptor cells

Question 28

What is a detailed explaination of smell?

Answer 28

Binding of odorant molecules to receptors triggers a signal transduction pathway, generating action potentials that travel to the olfactory bulb of the brain

Question 29

How can mammals distinguish from thousands of different odors?

Answer 29

They have hundreds or thousands of genes that encode olfactory receptors