Final Test Flashcards
What does stimulation of the following CNS components elicit?
- Lower CNS: Simple responses like reflexes
- Thalmus: Crude awareness of location and sensation type
- Cerbral cortex: Precise location and type of stimulus
The conscious awareness and interpretation of the meaning of sensations
Perception
- There is no perception of sensory impulses that do not reach the thalamus and cerebral cortex (e.g. BP and CO2)
Unique type of sensation such as touch, pain, vision, and hearing. What are the two classes of this?
- Sensory modalities
- General and Special senses
Tactile, thermal, pain, proprioceptive, and dynamic sensations are this specific type of sense.
- General senses (Somatic and Visceral)
Smell, taste, vision, hearing, and equilibrium are this type of sense.
- Special Senses
Conversion of stimulus energy into electrical energy
Transduction of stimulus
- Each type of sensory receptor transducers only one kind of stimulus (selectivity)
What are the different type of nerve microscopic appearances? (3)
- Free nerve endings: Pain, thermal, tickle, itch, some touch
- Encapsulated nerve endings: Pressure & vibration (lamellated), some touch (meisner)
- Seperate cells: Hearing, equilibrium, photoreceptors, gustatory
What are the two types of graded potentials produced by sensory receptors?
- Generator
- Receptor
Generator potentials
- Free nerve endings
- Encapsulated nerve endings
- Receptive part of olfactory receptors
Receptor potentials
- Trigger release of neurotransmitter
- Hearing, equilibrium, taste, and sight
- NOT the first order neuron
Sensations that arise from stimulation of sensory receptors embedded in the skin, subcutaneous, mucous membranes, muscle, tendons, joints, and inner ear
- Somatic
- Tactile, thermal, pain, proprioceptive
What are the three cerebral cortex functional areas?
- Motor area: Voluntary motor functions
- Sensory area: Conscious awareness of sensation
- Association area: Integrate diverse information for purposeful action
What are the sensations of the posterior column-medial lemniscus pathway? (5)
- Fine touch
- Sterognosis: Recognize size, shape and texture by feeling it
- Graphesthesia: Ability to feel and identify a symbol drawn on the body
- Proprioception
- Vibratory
Spinothalamic Pathway
- Originates in the spinal cord and goes to cerebral cortex
- AKA anterolateral pathway
- Carries nerve impulses of pain, thermal, tickle, itch, vibration, and some touch
- composed of three neuron sets
The impulses in this pathway are important for posture, balance, and coordination of skilled movement. It is not consciously perceived.
Somatic sensory pathway to cerebellum
Major motor pathways concerned with voluntary movement
- Pyramidal tracts
- Composed of lateral and anterior corticospinal tract
- Also called direct motor pathways
Controls automatic movements of skeletal muscles and muscle tone
Basal ganglia
Abnormal condition in which movements are jerky and uncoordinated
Ataxia
Shaking that occurs during deliberate voluntary movement, especially during visually guided movement towards a target
Intention tremor
What are the two chemical senses?
Olfaction and gustation
Sites of olfactory transduction
Olfactory hairs (cilia projecting from dendrites)
This is the only sensation to reach the cerebral cortex without synapsids in the thalamus
Olfactory sensations
Reduced ability to smell
Hyposmia
Total lack of sense of smell
Anosmia
- Can be caused by zinc deficiency
What are the three types of papillae that contain taste buds?
- Vallate papillae
- Fungiform papillae (mushroom shaped)
- Foliate papillae (Mostly loss during childhood)
What papillae does not contain taste buds?
Filiform papillae
What is the order of taste threshold from lowest to highest?
Bitter < Sour < Remaining primary tastes
What kind of potential is involved with the gustatory pathway?
Receptor potential
What cranial nerves are associated with the gustatory pathway?
- Facial nerve (VII): Anterior 2/3 of tongue
- Glossopharyngeal (IX): Posterior 1/3 of tongue
- Vagus nerve (X): Throat and epiglottis
What is the alternate name for eyelids?
Palpebra
Misalignment of one eye so that its line of vision is to parallel with that of the other eye
Strabismus
Rapid involuntary movement of the eyeballs
Nystagmus
- Horizontal nystagmus occurs more often than vertical
Cornea
- Curved to focus light
- Three layers
Sclera
- White of the eye
- Covers entire eyeball except cornea
- Gives shape to eyeball
Vascular tunic
- Middle layer of eye
- Has three parts: Choroid, Ciliary body, and Iris
Choroid
- Highly vascular
- Lines most of internal surface of sclera
- Provides nutrients to posterior surface of sclera
Ciliary body
- Consist of process and muscle
Loss of transparency of the lens
Cataracts
Results from high intraocular pressure
Glaucoma
Pressure from posterior chamber pushes the iris forward, closing the ocular angle
Primary closed angle glaucoma
Ocular angle remains open, but abnormalities in the trabecular mesh work impede outflow of aqueous humor
Primary open angle glaucoma
Near vision
- AKA Accommodation
- Increase in the curvature of the lens
Loss of elasticity of the lens with aging
Presbyopia
Nearsightedness
- Myopia
- Eyeball is too long relative to focusing power of the cornea and lens
- Fix is concave lens
Farsightedness
- Hypermetropia
- Eyeball is too short relative to the focusing power of the cornea and lens
- Fix is convex lens
Irregular curvature of either the cornea or the lens
- Astigmatism
- Fix is use of a lens that rotates the axis of the light going into the eye
The medial movement of two eyeballs so that both are directed toward an object being viewed
Convergence
Loss of vision in an otherwise normal eye
Amblyopia
What does the outer ear consist of?
- Auricle
- External auditory canal
- Eardrum
What parts landmark the middle ear?
Separated front he external ear by the ear drum and from the inner ear by the oval window and the round window
What does the middle ear consist of?
The auditory ossicles
- Transmit vibrations
- Malleus (Hammer), Incus (Anvil), and Stapes (Stirrup)
What are the two muscles of the middle ear and what do they do?
- Tensor tympani: Increases tension on eardrum to prevent damage from loud noises
- Stapedius: Dampens vibrations of the stapes due to loud noises
Abnormally sensitive hearing
- Hyperacusia
- Usually result of paralysis of the stapedius muscles
Connected the middle ear with the nasopharynx
Auditory tube AKA Eustachian tube
Eustachian Tube
- Normally closed but opens with swallowing and yawning
- Equalized pressure in middle ear
- Common pathway for pathogens
What are the two main divisions of the inner ear?
Bony labyrinth and membranous labyrinth
This fluid found in the inner ear is chemically similar to CSF
Perilymph
*surrounds the membranous labyrinth
Fluid within the membranous labyrinth
Endolymph
- Has high levels of potassium for generation of auditory signals
What are the two types of equilibrium?
- Static: Position of body relative to gravity
- Dynamic: Position of body relative to sudden movements
What makes up the vestibular apparatus?
Saccule, Utricle, Semicircular ducts
