A3 Perception

Question 1

Which receptors sense heat/coldness? Where are they?

Answer 1

Thermoreceptors
Skin, Hypothalamus

Question 2

Which receptors sense pressure? Where are they?

Answer 2

Mechanoreceptors
ears, skin

Question 3

Which receptors recognize chemicals and pH and make you smell and taste? Where are they?

Answer 3

Chemoreceptors
Tongue, nose, tissues

Question 4

Which (in general) receptors sense light/ make you see? Where are they?

Answer 4

Photoreceptors
Retina

Question 5

What are rods? How many are connected to a bipolar cell?

Answer 5

• Rods detect light & dark lights
• work better in darkness
• 3 are connected to one bipolar cell, and the infromation is mixed, so the image is poorly resolved

Question 6

What are cones? How many are connected to a bipolar cell?

Answer 6

• Detect colours red, blue and green
• one is connected to a bipolar cell
• abundant in the fovea
• better during the day, as it needs a few photons to be activated

Question 7

What are the cells called after the bipolar cells? What are they?

Answer 7

Ganglion cells - their axons form the optic nerve and transmit the information to the brain

Question 8

How do people hear?

Answer 8

1. As soundwaves hit the eardrum, it vibrates, which is transmitted to the ossicles and amplified, as the force distribution is reduced.
2. The vibrations are sent through the oval window, which displaces the fluid in the cochlea.
3. There is a membrane in the cochlea, which moves in response to a movement of the fluid. As it is in the whole cochlea, higher frequencies get detected closer to the base.
4. Hair cells are bent in the membrane in response to a specific frequency, so every hair cell has it’s particular frequency.
5. The hair cells fire an impulse which is transmitted to the auditory nerve and then to the brain.

Question 9

What is the vestibular system?

Answer 9

In the semicircular canals, there are hair cells in caps called cupula and when the head moves, the fluid in those canals exert a force on the cupula, which sends a nerve impulse.

Question 10

How are movements in all 3 planes detected?

Answer 10

the semicircular canals are at 90° to eachother, so it works in every direction

Question 11

How does olfaction work?

Answer 11

The olfactory epithelium is embedded with chemoreceptros,and a mucus, in which the odorant molecules dissolve before binding to chemoreceptors. This binding then triggers a nerve impulse, which is the scent perceived by the brain.

Question 12

What is trichromatic vision?

Answer 12

Seeing all colours, having 3 different types of cones.

Question 13

How does red-green-colour-blindness come by?

Answer 13

The gene coding for the red and green cones lie on the x-chromosome, and if either gene is mutated, red and green cannot be distinguished.

Question 14

Why is red-green colour blindness more abundant in males?

Answer 14

The genes coding for red and green photoreceptors lie on the X-chromosome and is recessive, so if there is a mutation, males will be affected, but females are saved by the same gene on the other x-chromosome, if it isn’t mutated as well.

Question 15

How do cochlear implants help in deaf patients?

Answer 15

External part: transmitter detects sound and transmits signals to internal part
Internal part: receives transmissions and produces electrical signals via electrodes in the cochlea, which are sent to the auditory nerve