Nervous System - Sense Organs Flashcards
What is a receptor?
Specialised cells that detect stimuli and and convert them into nerve impulses
What is a sense organ?
A concentration of receptors with the same function
Functions of the ear
Hearing and balance
Location of the ear
Pinnae positioned outside the skull on opposite sides of the head, rest of the ear embedded in the temporal bone
Three parts of the ear
Outer ear
Middle ear
Inner ear
Parts which make up the outer ear
Pina
External auditory canal
Structures making up the middle ear
Tympanic membrane (eardrum) Ossicles Oval window Round window Opening to the Eustachian tube
Parts which make up the inner ear
Bony labyrinth (perilymph filled)
Membranous labyrinth
Vestibular apparatus
Cochlea
The vestibular apparatus consists of…
The utriculus and the sacculus
Three semicircular canals
What are maculae?
Special receptors found in the sacculae and utriculae
The function of the maculae
Generate impulses when stimulated by gravity during a change in position of the head
The impulses from the maculae go to…
The cerebellum (which coordinates muscles to restore balance)
What are cristae?
Sensory organs of rotation found in the ampullae of the semi-circular canals
Cristae are stimulated by…
Movement of the endolymph of the semi-circular canals due to movement of the head
Impulses from the cristae go to…
The cerebellum (which coordinates muscles to restore balance)
The type and location of receptors which detect light stimuli
Photoreceptors in the eye
The shape of the eye
Pretty spherical
Purpose of the eyelids and eyelashes
Protect the eye from foreign objects
Describe the conjunctiva
Thin mucous membrane containing pain receptors that are stimulated by dust/other particles and trigger blink reflex
Location of the conjunctiva
Covers the front of the eye and the inner surface of the eyelid