Ch. 18 Senses Flashcards
Rods and cones
Folded disc membranes contain pigments that absorb light.
Rods: Most of visible spectrum
Cones: 3 types: Specific wavelengths of light Color vision
Structure of the Retina (Going deep)
- Blood vessels and nerve fibers
- Ganglion Cell
- Interplexoform cell
- Bipolar cell
- Horizontal cell
- Cone
- Rod
Focus and accommodation
Refraction of light through the cornea and the lens
Change the shape of the lens and the focal point changes
We focus on near or distant objects
Lens flattens for distant objects, shortens for close objects
The optic chasm (binocular vision)
Images captured on the left side of both eyes are processed in the left visual cortex
A comparison of the images gives depth of view
Visceral Senses
Hunger, nausea, irritation, chemical, temperature, stretch, pain
Somatic Senses
Vibration, pressure, stretch, temperature, touch, pain
Sensory receptors (surface to deep)
- Merkel discs (light touch)
- Meissner corpuscle (touch, two point)
- Free nerve ends (pain, itch, temp, movement)
- Ruffini end organ (touch, stretch, pressure)
- Follicle receptor (bending hair)
- Pacinian corpuscle (pressure)
Mechanoreceptor
Responds to mechanical force
Thermoreceptor
Responds to change in temperature
Chemoreceptor
Responds to chemicals
Photoreceptor
Responds to light (photons)
Nocireceptor
Responds to harm (damage)
Primary receptors (Responses)
The receptor is on the axon of the neuron and triggers an action potential
Secondary receptor (Responses)
The receptor has a synapse on the neuron and a chemical signal triggers action potential
Accommodation (adaptation)
Responses
Decreased sensitivity to a persistant stimulus
Special senses
Senses that are confined to an organ Olfaction (smell) Taste Vision Hearing Balance
Muscles of the eye
Superior rectus Medial rectus Lateral rectus Inferior rectus Superior oblique Inferior oblique
Superior rectus (muscle)
Elevates, medially deviates eye
Medial rectus (muscle)
Medially deviates eye
Lateral rectus (muscle)
Laterally deviates eye
Inferior rectus (muscle)
Depresses, medially deviates eye
Superior oblique (muscle)
Depresses, laterally deviates eye
Inferior oblique (muscle)
Elevates, laterally deviates eye
External ear
Function is to gather in the sound waves
Middle ear
Where we transmit vibrations through to the inner ear
Inner ear
Where we register sound
Determining sound frequency
The thickness of the basilar membrane determines where a sound of a certain frequency passes through
Vibrations disturb hair cells opening K+ channels depolarizing hair cells
Balance
Registered by the vestibule and the semicircular canals
Olfactory Senses (Surface to deep)
Olfactory vesicle Cilia (olfactory hairs) Dendrite Olfactory neuron Support cell Basal cell Axon Foramen in cribiform plate Mitral cell
Neuronal Pathways (Olfaction)
- Olfactory nerve fibers & Olfactory bulb
- Olfactory tract
- Medial olfactory area
- Intermediate olfactory area
- Lateral olfactory area
Taste (Structures)
Epiglottis, Palatine tonsil, Vallate papilla, Filiform papilla, Dorsum, Foliate papilla
Taste buds (Surface to deep)
- Taste pore
- Gustatory hairs
- Taste cell
- Support cell
- Basal cell
- Sensory Neuron
Neuronal Pathways (Taste)
- Vagus (X)
- Glossopharyngeal IX
- Facial VII
- Trigeminal V
All go to the Thalamus, then to Taste area of cortex
Lacrimal apparatus (tears) Pathway
- Lacrimal gland
- Lacrimal ducts
- Punctum
- Lacrimal canaliculi
- Lacrimal sac
- Nasolacrimal duct
Visible light
380-750nm
Neuronal Pathways: Hearing
Vestibulocochlear nerve to cochlear nucleus
To the olivary nucleus or the inferior colliculus
To the thalamus
To the auditory cortex
Neuronal Pathways: Balance
Vestibulocochlear nerve to vestibular nucleus
To cerebellum that affects postural muscles
To motor nuclei that control eye movement
To thalamus
To vestibular area of cortex
