Chapter 13- Sensory systems (1)

Question 1

What are the types of external stimuli that can be sensed by an animal?

Answer 1

1- Mechanoreceptors sense touch and audition (hearing)

2- Chemoreceptors sense taste and smell

3- Photoreceptors sense light

4- Thermoreceptors sense hot and cold

Question 2

Give an example of internal stimuli that can be sensed

Answer 2

Chemoreceptors sensing blood oxygen levels

Question 3

What is the sensory system?

Answer 3

Converts a sensory stimulus into neurobiological activity.

Question 4

Is the sensory the afferent or efferent part of the nervous system?

Answer 4

Afferent part of the nervous system

Question 5

What is the stimulus first modified by? Give an example.

Answer 5

An accessory structure. Examples include the crystalline lens

Question 6

The function of any given skin receptor is determine by what?

Answer 6

The nature of its accessory structure

Question 7

Give some types of sensory receptors

Answer 7

1- A gustatory receptor (taste buds)

2- Photoreceptors

Question 8

What is pressure waves in the air the same as?

Answer 8

Sound

Question 9

What happens when an object vibrates? What are they detected by?

Answer 9

It causes air molecules to squeeze together or spread out.

These vibrations are detected by the ear.

Question 10

Sound waves are often represented by what type of wave?

Answer 10

Transverse waves

Question 11

The frequency of the wave determines what?

Answer 11

The pitch and is measured in hertz.

Question 12

The intensity of the wave determines what?

Answer 12

The loudness of the sound.

Question 13

What does the outer ear consist of?

Answer 13

1- The pinna

2- The external auditory meatus

Question 14

What does the outer ear do?

Answer 14

Helps to channel sounds and play a role in sound localisation.

Question 15

Sound waves that travel down the outer ear impact on what?

Answer 15

The tympanic membrane causing it to vibrate.

Question 16

When the tympanic membrane vibrates, what transfers it and what does it cause?

Answer 16

These vibrations are then transferred by the bones of the middle ear, causing movement of the oval window, which causes movement of the fluid within the inner ear.

Question 17

What problem does the middle ear solve?

Answer 17

Allows greater pressure change in order for the tympanic membrane to cause fluid movement in the inner ear.

Question 18

What are the ways in which the middle ear allows greater pressure?

Answer 18

1- The middle ear contains bones called the malleus, incus, and stapes.

• These act as a biological lever, so that small movements in the tympanic membrane are amplified onto the oval window.

2- The pressure on the tympanic membrane is spread over a large surface area.

• The area of the oval window is much smaller, which concentrates the pressure and increases the amount of force.

Question 19

How many skeletal muscles freeze the bones of the middle ear? What do they protect against?

Answer 19

2

These protect against loud sounds.

Question 20

The eustacean tube connects the middle ear with what? What does this do?

Answer 20

The nasal cavity

This equalises the pressure of the middle ear to atmospheric pressure.

This is important in making sure to stop your ear drum blowing as external pressure changes e.g, flying.