Rest & Digest division of ANS
Parasympathetic
Parasympathetic fibers of what nerve accommodate close vision?
Oculomotor (III)
Info from balance receptors goes where?
Brain stem reflex centers
Why are sympathetic responses generally system wide?
NE and epinephrine are secreted into the blood as part of the sympathetic response
What sympathetic fibers form a splanchnic nerve?
Those that pass through the trunk ganglion to synapse in collateral or prevertebral ganglia
Where would you find cholinergic nicotinic receptors?
Skeletal muscle, adrenal and medulla
Conscious perception of vision is associated with which lobe?
Occipital lobe
Why can corneas be transplanted without tissue rejection?
The cornea has no blood supply
What are otoliths?
Each of three small oval calcareous bodies in the inner ear of vertebrates, involved in sensing gravity and movement.
An essential part of the maculae involved in static equilibrium
What is the function of the reticular formation?
Regulates states of consciousness and arousal
The parasympathetic ganglion which serves the eye?
Ciliary ganglion
Sympathetic nerves leave the spinal cord at what level?
First thoracic
What is automatic dysreflexia?
Uncontrolled activation of autonomic neurons
What is the primary visual cortex?
Conscious perception of visual images (seeing) occurs.
Action of the inferior oblique
Turns eye upwards and laterally
What is striate cortex?
Also called primary visual cortex, provides form, color, and motion inputs to visual association areas collectively called the prestriate cortices
What does the tenth cranial nerve innervate?
Liver, gallbladder, stomach, small intestine, kidneys, pancreas, and the proximal half of the large intestine
The oval window is connected to which passageway?
Scala vestibuli
The only special sense not fully functional at birth?
Vision
Cardiovascular effects of the sympathetic division
Constriction of most blood vessels, dilation of vessels serving skeletal muscle, increase of heart rate and force
Stimulation of sympathetic division causes
Increased blood glucose, decreased GI peristalsis, and increased heart rate and blood pressure
Function of rods in the eye
Dim light and peripheral vision
What is olfaction and what does it involve?
Olfaction: sense of smell
Involves chemoreceptors
Best stimulated by chemicals dissolved in liquid
What happens in dark adaptation?
Involves accumulation of rhodopsin
In the retina, the axons of which neuron layer form the optic nerves?
Ganglion cells
Visual processing in the thalamus contributes to what factors?
Depth perception, high-acuity vision, movement perception
The "fight or flight" is from which division?
Sympathetic
Photoreceptors ________________________.
Package visual pigment in membrane-bound discs, which increases the
efficiency of
light trapping
Where is the blind spot of the eye?
Optic disc
Where would you find autonomic ganglia?
Head, cervical region, close to the effectors they serve
The order that light passes through the eye
Vitreous chamber, layer containing axons of ganglion cells, layer of ganglionic cells, layer of bipolar cells, layer containing cell bodies of rods and cones, layer containing the outer segments of rods and cones embedded in the pigment layer
What is the bone pillar located in the center of the cochlea?
Modiolus
What is the ANS?
General visceral motor system
Erection of the penis or clitoris is the result of what?
Primarily parasympathetic control
Control center of the body
Hypothalamus
What are splanchnic nerves?
Most of the preganglionic fibers from T5 down synapse in collateral ganglia, and so most of these fibers enter and leave the sympathetic trunks without synapsing. They form several nerves called splanchnic nerves
What is the lateral geniculate body of the thalamus?
A relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina. The LGN is the main central connection for the optic nerve to the occipital lobe.
Most of the body's sensory receptors are found where?
Eyes
Where are taste buds found?
Fungiform, foliate, vallate papillae
What are gustatory receptors?
Gustatory epithelial cells - taste cells
Different parts of sound
Sound: pressure disturbance
Frequency: the number of waves that pass a given point in a given time
Wavelength: distance between two crests
Pitch: different sound frequencies
Quality: a mixture of several frequencies
Amplitude: sound's intensity
Decibels: loudness measured in logarithmic units
Loudness: subjective interpretation of sound's intensity
Beta 1 Receptors
Located in the heart, increase cardiac activity
What is malnutrition-induced blindness?
Prolonged Vitamin A deficiency
Parasympathetic outflow from the head involves what nerve?
Vagus nerve
What is hyperopia?
A condition in which visual images are routinely focused behind rather than on the retina - commonly known as farsightedness
Differences between somatic & autonomic nervous systems?
Their effectors & their efferent pathways
Secretions of the adrenal medulla are what effects?
Supplement the effects of sympathetic stimulation
Where do nerve fibers from the medial eye go?
Cross over to the opposite side at the chiasma
What is involved with dark adaptation?
Cones do not function (visual acuity decreases) and rod function resumes when sufficient rhodopsin accumulates
What is involved with equilibrium?
Vestibular nuclei receive impulses from the equilibrium apparatus of the inner ear and help to maintain balance by varying muscle tone of postural muscles
Visible light can fit between which wavelengths?
UV and infrared
What is sound localization?
Requires input from both ears, uses time differences between sound reaching the two ears - difficult to discriminate sound sources in the midline
What is the suprachiasmatic nucleus?
Serves to synchronize body rhythms with natural light and dark
What are the receptor membranes of gustatory cells?
Gustatory hairs
What prevents the eye from sticking together when closed?
Tarsal gland secretions
What do autonomic ganglia contain?
Cell bodies of motor neurons
Most parasympathetic fibers arise from which nerve?
Vagus nerve (CN X)
What are alkaloids?
- Bitter taste is elicited by alkaloids (such as quinine, nicotine, caffeine, morphine, and strychnine) as well as a number of nonalkaloid substances, such as aspirin.
What are ceruminous glands?
Modified apocrine sweat glands
What can a parasympathetic preganglionic axon do once it reaches a trunk ganglion?
Synapase with a ganglionic neuron in the same trunk ganglion, ascend or descend the trunk to synapse in another trunk ganglion, pass through the trunk ganglion without synapsing with another neuron
Vagus nerve plexus
Cardiac, pulmonary, esophageal
What causes conduction deafness?
Impacted cerumen, middle ear infection, otosclerosis
Raynaud's Disease
Characterized by exaggerated vasoconstriction in the extremities
How do emotions influence autonomic reactions?
Primarily through integration in the hypothalamus
What happens to outer hair cells as sound increases in the spinal organ of Corti?
Outer hair cells stiffen the basilar membrane
Effects of parasympathetic tone
GI and UT activity, lowers heart rate
Chemicals associated with sweet, umami, bitter, sour & salty
Sweet: Sugars, saccharin, alcohol, lead salt
Umami: glutamate and aspartate
Bitter: alkaloids such as quinine, nicotine, caffeine
Sour: Acids, hydrogen ions
Salty: metal ions (inorganic salts)
Meniere's Syndrome
- Affects both the semicircular canals and the cochlea
- may result from distortion of the membranous labyrinth by excessive endolymph accumulation.
- Less severe cases can usually be managed by antimotion drugs.
- For more
debilitating attacks, salt restriction and diuretics are used to
decrease overall
extracellular fluid volumes.
Which structure cannot be seen with an ophthalmoscope?
Optic chiasma
Where are action potentials generated within the retina?
Ganglion cells
What would damage to the medial rectus affect?
Convergence
What effectors are directly controlled by the autonomic nervous system?
Smooth, cardiac, most glands
Parts of external ear
Pinna, external auditory meatus, tympanic membrane
How do visceral reflex arcs differ from somatic?
Visceral arcs involve two motor neurons
What stimulates olfactory and taste buds?
Substances in solution
Characteristics of olfactory receptor cells
They are ciliated chemoreceptors with a short lifespan of about 60 days
What are optic vesicles?
First vestiges of eyes in the embryo
What type of neurons are replaced throughout adulthood?
Olfactory receptor cells
What are beta blockers?
Drugs that attach to beta receptors to dilate lung bronchioles. Decrease heart rate and blood pressure
What causes motion sickness?
Results from mismatch between visual and vestibular inputs
When we see the color of an object, what is happening to the light?
All light is being absorbed by that object except the light being experienced
What does the iris regulate?
Amount of light passing to visual receptors of eye
Where are receptors for hearing located?
Cochlea
The tarsal plate is connected to which structure?
Levator palpebrae
What is the macula?
Receptor for static equilibrium
ESSAY QUESTION: Meniere's Syndrome
- May result from distortion of the membranous labyrinth by excessive endolymph accumulation
- Affects both semicircular canals and cochlea
- Attacks of nausea, vertigo, vomiting
- Howling tinnitus is common
- Less severe cases can usually be managed by antimotion drugs
- For more debilitating attacks, salt restriction and diuretics are used to decrease overall extracellular fluid volumes.
ESSAY QUESTION: Orthostatic Hypotension
- Low blood pressure following changes in position
- Aging pressure receptors become less responsive to changes in BP
- Aging CV centers fail to maintain healthy BP
- Alleviated by changing position slowly
- A decrease in systolic blood pressure greater than 20 mm HG after moving from a supine to sitting is typically indicative of orthostic hypotension
- Elastic stockings and ace wraps can be used to wrap extremities
- Blood pressure medication may be used to increase BP