A&P 1: Special Senses Flashcards
What are the two classes of sensory modalities?
General senses
Special senses
General senses include what two senses?
Somatic Senses
Visceral Senses
What is the first step in the process of sensation?
Activation of sensory receptors by stimulus
Sensory receptors comprise either _____ or _____
Specialized cells
Dendrites of sensory neuron
4 events required for sensation
Stimulation
Transduction
Generation
Integration
For stimulation of the sensory receptor to occur, the stimulus must occur within _______?
Receptive field of the receptor
Body region where stimulation causes a response
Sensory receptors transduces energy in a stimulus into a _______
Graded potential
Sensory receptors can be placed into 3 classifications
Microscopic appearance
Origin of stimuli
Type of stimulus
3 classifications by microscopic appearance
Free nerve endings
Encapsulated nerve endings
Separated cells
Define Free Nerve Endings
Bare dendrites with no structural specialization
Define Encapsulated Nerve Endings
Dendrites enclosed in connective tissue capsule
Define Separate Cells
Specialized cells that synapse with first order sensory neurons
What do separate cells detect?
Hearing/equilibrium hair cells
Photo receptors
Gustatory receptors
Sensory receptors produce what two types of graded potentials?
Generator potential
Receptor potential
What produces Generator Potentials?
Free Nerve endings
Encapsulated nerve endings
Receptive part of olfactory receptors
A cold-sensitive receptor is an example of what type of sensory receptor?
Free Nerve Ending
Lamellated corpuscle is an example of what type of sensory receptor?
Encapsulated nerve ending
Of the two types of graded potentials made by sensory receptors, which one is not a first-order neuron?
Receptor potential
Define Adaptation
Decrease in generator/receptor potential amplitude to a prolonged stimulus
3 examples of rapidly adapting receptors
Touch
Pressure
Smell
3 examples of slow adapting receptors?
Pain
Proprioception
Chemical
Define somatic sensations
Arise from stimulation of sensory receptors in skin/subcutaneous layer in mucus membrane, muscles, tendons, joints and inner ear
Define Cutaneous sensations
Somatic sensations that arise from stimulating surface of skin
Free nerve endings of tactile sensations sense what stimuli?
Encapsulated sense what?
Itch and tickle
Touch, pressure, vibration
Define Touch Sensation
Stimulation of tactile receptors in skin or subcutaneous layer
What are the 2 types of touch?
Crude- Something is contacting but can’t determine location, shape, size and texture
Fine- specific information is provided, location, shape, size, texture
Define Pressure
Sustained sensation that is felt over larger area than touch due to deformation of deeper tissues
Define Vibration
Rapid and repetitive sensory signals from tactile receptors
What are the 2 types of receptors for vibration?
Meissner corpuslces- low-frequency vibrations
Pacinian corpuscles- higher frequency vibrations
Define itch
Stimulation of free nerve endings by certain chemiclas, possible local inflammatory response
Define tickle
Sensations arising from free nerve endings and lamellated corpuscles
Thermoreceptors are unspecialized free nerve endings that respond to changes primarily within the ____ range
Innocuous
Where are thermal sensation receptors?
Skin
Cornea
Tongue
Bladder
Pain receptors are found in every tissue in the body except?
Brain
Tissue irritation/injury release what 3 chemicals that stimulate nociceptors?
Kinins
Prostaglandins
K+ ions
Define Kinins
Polypeptides that cause vasodilation, increase vessel permeability, and chemotactic agents for phagocytes
Define Prostaglandins
Lipids that intensify effects of histamine, kinin and stimulate emigration of phagocytes through capillary walls
Types of pain are differentiated based on?
Types of nerve fibers that propagate impulses
Where in the body the type of pain can occur
Fast pain fibers are AKA?
Acute
Sharp
Pricking
Pain by location of receptors can be divided into 3 types
Superficial
Deep
Visceral
When does referred pain usually occur?
Nerve fibers from HIGH sensory input and fibers from LOW input converge on same levels of the spinal cord
What are the 3 types of proprioceptors
Muscle spindles
Tendon organs
Joint kinesthetic receptors
Define Muscle spindles
Proprioceptors in skeletal muscles that participate in stretch reflexes
Define Tendon Organs
Located at junction of tendon and muscle, provide info about changes in muscle force
What is the purpose of Tendon Organs?
Protect tendons and muscles from damage from tension
Define Joint Kinesthetic Receptor
Provide info about parameters associated with movement of synovial joints
What are the parameters of joint kinesthetic receptors?
Pressure
Velocity changes
Tension
Where are joint kinesthetic receptors located?
Around articular capsule of synovial joint
Olfaction produces a ____
Gustation produces a _____
O= generator potential G= receptor potential
Olfactory epithelium consists of what 3 kinds of cells?
Olfactory receptors
Supporting cells
Basal stem cells
Olfactory supporting cells are AKA ?
Sustentacular cells
Olfactory receptors are what kind of neurons?
Bipolar first-order neurons
Each olfactory receptor has what 3 parts?
Axon ending in olfactory bulb
Knob shaped dendrite
Cilia projecting from dendrite
What are the olfactory hairs?
Cilia projecting from dendrites of olfactory receptors
What is the site of olfactory transduction?
Olfactory hairs
How are olfactory responses initiated?
Chemical stimulation of odorant molecule that produces a generator potential
What are the olfactory supporting cells?
Columnar cells of mucous membrane lining the nose
Supporting cells in the nose provide what 3 things?
Physical support
Nourishment
Electrical insulation
What is unique about the basal stem cells?
Undergo continuous division producing new olfactory receptors since they only life for a month
What are Olfactory Glands
What are they AKA?
Produce mucus
Bowman’s glands
What is the function of the Olfactory Glands?
Moisten epithelium
Dissolve ordorants
What CN innervates supporting cells and olfactory glands?
CN7
Where do olfactory nerves terminate?
Olfactory bulbs- paired gray matter masses
Site of end of first order and synapse with second order neurons
What is formed when olfactory bulb axons extend posteriorly?
Olfactory tract
Where is the primary olfactory area?
Lateral olfactory area
Site of conscious smell beginning
What is unique about the olfactory pathway?
Only sensation that reaches cerebral cortex without synapsing with thalamus first
How do olfactory senses trigger emotion/memory linked responses to odors?
Olfactory tract projects to limbic system and hypothalamus
Where do second order olfactory neurons project to?
Olfactory bulb to brain to form a sensory map
What kind of deficiency is the cause of many cases of anosmia?
Zinc- growth factor for receptors of chemical senses
Taste buds are located in what 4 areas?
Tongue
Soft palate
Pharynx
Epiglottis
Taste buds consist of what 3 types of cells?
Gustatory receptor cell
Supporting cell
Basal cell
Where is a taste pore?
Apex of taste bud
Define gustatory hair
Long, single microvillus projecting through taste pore
What is the sequence of cellu progression for gustatory cells?
Basal->supporting->gustatory
Gustatory live for 10 days
What is the site of taste transduction?
Gustatory hairs
Sweet tastes are associated with what?
Why?
Safe food
Requirement for carbs
What is the conventional receptor location for sweets?
Tip of tongue
Sour tastes are associated with what?
Spoiled foods
What is the conventional receptor location of sours?
Back sides of tongue
Bitter tastes are associated with what?
Poisonous foods
Where is the conventional receptor location of bitters?
Back middle of tongue
Salty tastes are associated with what?
Sodium Chloride
Where is the conventional receptor location of salty?
Sides of tongue
Umami is the taste of what?
Amino acids
Meaty, savory, broth like
Taste buds occur in elevations of the tongue called what?
Papillae
What are the 3 types of papillae?
Vallate
Fungiform
Foliate- lost during childhood
Define filiform papillae
Papillae with tactile receptors to distinguish food textures but can’t taste
What taste has the lowest threshold?
Bitter
Sour slightly higher
Define flavor
Combination of taste plus odor (retronasal olfaction)
Define retronasal olfaction
Volatile food chemicals carried into nasal cavity from behind
Olfactory epithelium can act in what two types of olfaction?
Retronasal
Orthonasal
What sense pathway doesn’t have an axon?
What are they called instead?
Gustatory
Graded potential produced called receptor potentials
What 3 CNs make up the gustatory pathway?
CN 7- anterior 2/3 of tongue
CN 9- posterior 1/3 of tongue
CN 10- throat and epiglottis
Where is the gustatory nucleus?
Medulla obonglata
Where do gustatory axons project to from the medulla?
Limbic
Hypothalamus
Thalamus
Where is the primary gustatory area?
Parietal lobe of cerebral cortex to give conscious perception of taste
3 functions of palpebrae
Protect from light
Protect from objects
Spread lubrication
Define palpebral fissue
Space between upper and lower eyelids
Define Commissures
Angles of the palpebral fissure
Define lacrimal caruncle
Medial commissure containing sebaceous and sudoriferous glands
What are the structures of the eyelid from superficial to deep?
Epidermis Dermis Subcutaneous tissue Fibers of orbicularis oculi muscle Tarsal plate Tarsal glands Conjunctiva
Define Tarsal Plate
Fold of CT that gives form and support to eyelids
Define Tarsal Glands
Secretes fluid to keep eyelids from adhering to each other
Tarsal glands are AKA ?
Meibomian glands
Define Palpebral conjunctiva
Define Bulbar conjunctiva
P= lines inner aspect of eyelid B= on anterior surface of eyeball, covers sclera but not cornea
Define lacrimal apparatus
Group of structures that produce and drain tears
What are the 3 parts of lacrimal fluid
Salts
Mucus
Lysozyme
How is lacrimal fluid drained into the eye?
Excretory lacrimal duct on surface of conjunctiva of upper lid to pass medially over eye ball
What CN innervate the extrinsic eye muscles?
CN 3 4 6
Define cardinal directions of gaze?
6 of the 8 eye movements that are associated with a single extrinsic muscle
Define Strabismus
Imbalance of extrinsic eye muscles so lines of vision are not parallel
Deviant eye input disregarded and becomes functionally blind
What is the layman term for Strabisus?
Lazy eye
Define Nystagmus
Rapid involuntary movement of eyeballs
Sign, not a disease
What type of nystagmus is more frequent?
Horizontal
Define Vestibular Nystagmus
Eye movements that occur during/after rotational motion
What is horizontal gaze nystagmus useful?
Police use it to test field sobriety
What are the 3 layers of the eye?
Fibrous tunic
Vascular tunic
Retina
Define Fibrous Tunic
What are it’s two parts?
Superficial coat of eye that is avascular
Cornea and Sclera
Define Cornea
Transparent coat that covers iris
Curved so it can focus light
Sclera covers entire eye except for where?
Cornea
What is the function of the sclera?
Eye shape/rigidity
Define Vascular Tunic
What are the 3 parts?
Middle layer of eye
Choroid, ciliary body, iris
What are the functions of the choroid?
Vascularized to provide nutrients to posterior surface of sclera
What are the two parts of the Ciliary body?
Ciliary process
Ciliary muscle
Define Ciliary processes
Contain blood capillaries that secrete aqueous humor
Define Ciliary Muscle
Alters shape of lens
When the lens more spherical, what type of vision is allowed?
Contracted Ciliary, reduced tension of suspensory ligaments, more spherical shape for closer vision
Where does the iris connect to the eye?
Ciliary processes
What does the Parasympathetic and Sympathetic systems alter in the eye?
Parasymp- sphincter pupillae (circular muscle) to decrease pupil size
Symp- dilator pupillae (radial muscle) increases puil size
What is the inner coat of the eye?
Retina
What does the retina mark the beginning of?
Visual pathway
What is the only place in the body where blood vessels can be directly viewed and examined?
Retina
What is the optic disc?
Site where optic nerve exits eyeball