Chapter 13- Sensory systems (1) Flashcards
What are the types of external stimuli that can be sensed by an animal?
1- Mechanoreceptors sense touch and audition (hearing)
2- Chemoreceptors sense taste and smell
3- Photoreceptors sense light
4- Thermoreceptors sense hot and cold
Give an example of internal stimuli that can be sensed
Chemoreceptors sensing blood oxygen levels
What is the sensory system?
Converts a sensory stimulus into neurobiological activity.
Is the sensory the afferent or efferent part of the nervous system?
Afferent part of the nervous system
What is the stimulus first modified by? Give an example.
An accessory structure. Examples include the crystalline lens
The function of any given skin receptor is determine by what?
The nature of its accessory structure
Give some types of sensory receptors
1- A gustatory receptor (taste buds)
2- Photoreceptors
What is pressure waves in the air the same as?
Sound
What happens when an object vibrates? What are they detected by?
It causes air molecules to squeeze together or spread out.
These vibrations are detected by the ear.
Sound waves are often represented by what type of wave?
Transverse waves
The frequency of the wave determines what?
The pitch and is measured in hertz.
The intensity of the wave determines what?
The loudness of the sound.
What does the outer ear consist of?
1- The pinna
2- The external auditory meatus
What does the outer ear do?
Helps to channel sounds and play a role in sound localisation.
Sound waves that travel down the outer ear impact on what?
The tympanic membrane causing it to vibrate.
When the tympanic membrane vibrates, what transfers it and what does it cause?
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.
What problem does the middle ear solve?
Allows greater pressure change in order for the tympanic membrane to cause fluid movement in the inner ear.
What are the ways in which the middle ear allows greater pressure?
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.
How many skeletal muscles freeze the bones of the middle ear? What do they protect against?
2
These protect against loud sounds.
The eustacean tube connects the middle ear with what? What does this do?
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.
