The Senses Flashcards
What are the five human senses?
Touch, taste, smell, sigh, hearing
What is the organ for touch?
Skin
What receptors does the skin contain?
Touch and temperature
Name a location where the touch receptor is
Heel of the foot
Name a location where you could find a temperature receptor
Elbow
What is the organ of taste?
The tongue
Where are the receptors for taste?
In taste buds
What are the four basic taste receptors?
Sweet [at the tip]
Salt [at the sides near front]
Sour [sides near back]
Bitter [across back]
How do tastes persist?
Due to substances dissolving and lodging in the grooves of taste buds
What is the flavour of food?
It’s a combination of taste, smell, texture and temperature
What is the organ of smell?
Nose
What in the nose detects smell?
Olfactory neurones in nose
What is the organ of sight?
Eye
What is the function of the conjunctiva?
It’s a thin membrane protecting the sclera
Function of sclera?
Holds the eye in shape
What is the function of the cornea?
Focuses light on retina
Transparent part of sclera
Function of choroid?
Ensures there’s no internal reflection of light inside eye
How is the eye nourished?
Chorus has blood vessels
How is light absorbed into the eye?
The choroid contains a black pigment [melanin]
What is the function of the retina?
It is where the light receptors are located
What are the differences between and rod and cones
Rods - detect black and white Work in dim light Found all over retina Cones - detect colours Work in bright light Found at fovea
What is the pigment in rods known as?
Rhodopsin
Function of fovea?
Region of sharpest vision and most images are focused
What is the blind spot?
No rods or cones and it is not sensitive to light
Function of optic nerve?
Contains axons that carry impulses from the rods and cones to the back of the brain
What is the function of the lens?
Focus light on retina
[changes shape]
What is the function of the ciliary muscle?
Causes shape of lens to change when we look at near or far objects = accommodation
What connects the ciliary muscle to the lens?
Suspensory ligaments
What is the function of the iris?
Controls amount of light entering the eye
What gives a person dark coloured eyes?
Pigmented with melanin
Function of pupil
Let’s light into the eye
What is the aqueous humour?
Salt solution that holds the front of the eye in shape
What is the vitreous humour?
Keep the eye in shape
Supports the eye by exerting an outward pressure on the eyeball
What is the external muscle?
The eye is moved by the use of external muscles
How does size of pupil increase or decrease
Bright light - decreases so less light will enter
Dim light - increases, more light will enter
What is the organ of hearing?
The ear
What are the functions of the ear?
Hearing and balance
The ear is composed of three sections, what are they?
The outer, middle and inner ear
What are the outer and middle ear filled with?
Air
What is the inner ear filled with?
Lymph
What is sound caused by?
Vibrations in the air
How are vibrations collected?
By the outer ear, passed through the middle said where the vibrations are amplified and transferred to lymph in cochlea
Function of pinna?
Collects sound
Function of auditory canal?
Carries vibrations to the eardrum
Function of wax?
Secreted out eardrum and traps dust particles which protects ear
Function of eardrum
Separates outer ear from middle ear
Function of ossicles
Three tiny bones in the middle ear
Hammer, anvil and stirrup
They transmit vibrations from outer to inner ear and amplify vibrations
What is the smallest bone in the body?
The stirrup
Function of Eustachian tube?
Not part of ear
equalises pressure = prevents damage to eardrum
Function of cochlea?
Responsible for hearing = converts pressure waves into electrical impulses that travel to the brain
How does the cochlea work?
Vibrations arrive at cochlea from stirrup and pass through oval window and form pressure waves in lymph
The pressure waves stimulate receptors in cochlea and they cause electrical impulses to be sent to the brain.
Where in the ear contains receptor cells?
Organ of corti contain receptor cells that allow hearing
Where is balance detected?
In the vestibular apparatus in the inner ear
What does the vestibular apparatus consist of?
Three semicircular canals
What are the vestibular apparatus filled with?
Liquids and they have receptors located in different parts of vestibular apparatus which detect whether the head is vertical or not
Receptors in semicircular canals
All send impulses to cerebellum of the brain through vestibular nerve
Name a hearing disorder
Glue ear which is common in children
How does glue ear occur?
Caused by surplus sticky fluid collecting in the middle ear
What does the sticky fluid in glue ear do?
It prevents free movement of the eardrum and of small bones in the middle ear = some degree of deafness
Correction for glue ear?
Mild cases - nose drops can be taken to decongest and unblock Eustachian tube
Severe cases - Small tubes known as grommets are insisted into eardrum which forces fluid down Eustachian tube
To which part of the body does the Eustachian tube link the ear?
Pharynx
Name another part of the ear that has a similar function to that of the stirrup?
Hammer or anvil
Why are there three semi-circular canals in each ear?
To control in 3 planes
Name a part of the eye that has a corresponding function to cochlea in ear
Retina - both contain receptors
Name the structure that determines the diameter of the pupil
Iris
Why is there a mechanism to change the diameter of pupil
To control the amount of light entering eye
Certain parts of the eye are transparent and have curved surface, name two
Cornea, lens
Both focus light on retina
How does the curvature contribute to functioning of eye
Bend light
Why are the eyes of carnivores located relatively close to eachother?
Better focus on prey
Why are eyes of herbivores located more to the side of the skull?
Better detection of predators
What is the function of cones?
Detects colour
How does the iris work?
Changes size of pupil
Why are two eyes better than one?
Increased visual field
