Special Senses

Question 1

Special senses

Answer 1

Specialised sense organs that gather sensory information and change it into nerve impules

Eg: vision, hearing, balance, taste, smell

Question 2

General senses

Answer 2

All associated with the sense of touch, lack special sense organs

Information gathered by skin and other body tissues

Question 3

Olfactory system

Answer 3

Transmits sense of smell from olfactory epithelium of nasal mucosa to the olfactory cortex of the brain

Question 4

Olfactory pathway

Answer 4

Olfactory epithelium and olfactory nerves > olfactory bulb > olfactory tract and olfactory striae > olfactory cortical areas

Question 5

Olfactory epithelium (1st order)

Answer 5

Olfactory receptor cells
Supporting cells
Basal/progenitor cells

Question 6

Madeleine effect

Answer 6

Olfactory bulb (limbic system), close to amygdala (associated with emotion) and the hippocampus (associated with memory)

When you first encounter a smell it becomes linked to emotions felt at that time. Encountering the smell again can evoke the memory and associated emotion

Question 7

Disorders of sense of smell

Answer 7

Tumour - can compress the olfactory bulb and cause loss of smell

Question 8

Cells within the taste buds

Answer 8

Gustatory cells
Supporting cells

Question 9

Name the 5 basic flavours

Answer 9

Sweet
Sour
Salty
Bitter
Unami

Question 10

Taste neurons

Answer 10

1st order - carry taste sensation from taste buds to NTS

2nd order - from NTS in medulla oblongata to thalamus

3rd order - from thalamus to the post-central gyrus of the parietal lobe

Question 11

Vision neurones

Answer 11

1st order - (bipolar cells of retina) receives visual information from rods & cones

2nd order - (ganglion cell of retina) from optic nerve through optic chiasm and optic tract

3rd order - (lateral geniculate nucleus in thalamus) project to visual cortex as optic radiation

Question 12

Visual pathways

Answer 12

DORSAL - calculates objects location

VENTRAL - creates a sense of perception

Question 13

Rod cells

Answer 13

Detect in low light, don’t detect colour

Question 14

Cone cells

Answer 14

Detect in high light intensity, detect colour

Question 15

Vestibular nerve

Answer 15

Responsible for the efferent and afferent fibres that control balance and equilibrium

Question 16

Cochlear nerve

Answer 16

Carries efferent and afferent fibres for hearing

Question 17

Hearing neurons

Answer 17

1st order - bipolar neurons of spiral ganglion in cochlear nerve

2nd order - dorsal and ventral cochlear nuclei in the medulla oblongata

3rd order -

Question 18

Describe hearing

Answer 18

• Sound waves travel through external auditory canal and vibrate Tympanic membrane
• Vibrations are transmitted through the oval window causing a wave through the endolymphatic fluid
• This vibrates the organ of Corti’s basilar membrane, stimulating inner & outer hair cells
• Hair cells transmit action potentials to bipolar neurones in the spiral ganglion

Question 19

Vestibular neurone

Answer 19

1st order - vestibular ganglion

2nd order - vestibular nuclei in medulla oblongata

3rd order - thalamus

Question 20

What are the order of neurones

Answer 20

1st order - receive impulses and send them to spinal cord

2nd order - send impulses to the thalamus and cerebellum

3rd order - carry signals from thalamus to the primary sensory cortex

Question 21

What is the first order neuron

Answer 21

From spinal nerve to spinal cord

Question 22

What is the sencond order neuron

Answer 22

From the spinal cord to the thalamus

Question 23

What is the third order neuron

Answer 23

From the thalamus to the cerebral cortex