Ch. 14 - ANS
What regions do the preganglionic neurons of the parasympathetic division originate from?
Cranial & Sacral regions
What is autonomic tone?
The constant amount of activity from the autonomic nervous system; divided into sympathetic tone & parasympathetic tone.
What is the function of the iris?
To control how much light passes through the pupil into the eye.
What are the types of equilibrium?
Static equilibrium - Maintaining balance when the head & body are not moving, but the head is tilted.
Dynamic equilibrium - Maintaining balance during linear or rotational acceleration of the head or body.
If a patient experiences an increase in heart rate & decreased digestive activity, what division of the ANS is primarily responsible?
Sympathetic Division
What is the difference in the structure of sympathetic & parasympathetic neurons.
For sympathetic, preganglionic axons are short & postganglionic axons are long; for parasympathetic, the opposite occurs.
How does olfaction structurally differ from the other special senses?
In olfaction, stimuli are detected directly by the neurons of the cranial nerve, while other special senses use specialized receptor cells.
What are the accessory structures of the eye?
Eyelids, Eyebrows, Eyelashes, Conjunctiva, Lacrimal Apparatus, & Extrinsic eye muscles
Where are the different types of cholinergic receptors found?
Muscarinic - Sweat glands in the skin
Nicotinic - The membranes of all postganglionic neurons & cells of the adrenal medulla
Which cranial nerves have parasympathetic fibers?
Oculomotor (III), Facial (VII), Glossopharyngeal (IX), Vagus (X)
What are the cells of olfactory epithelium & what are their functions?
Olfactory neurons - Chemoreceptors to detect stimuli & transmit it to rest of brain
Basal cells - Stem cells that develop into olfactory neurons
Supporting cells - Columnar cells that surround & support olfactory neurons
What are the types of hearing loss?
Conduction hearing loss - An issue in the outer or middle ear prevents sound from reaching the inner ear (ex. excess earwax)
Sensory hearing loss - Failure to generate action potentials in the cochlea (ex. hair cell dysfunction)
Neural hearing loss - Failure to propagate action potentials through the cochlear branch of the vestibulocochlear nerve or CNS pathway.
What neurotransmitters are used by which divisions of the ANS & by what neurons?
Sympathetic Preganglion - ACh
Sympathetic Postganglion - ACh, Epinephrine, & Norepinephrine
Parasympathetic - ACh
What are the autonomic centers & where are they found?
They are centers that contain neurons that control preganglionic sympathetic & parasympathetic neurons; found in the reticular formation.
What cranial nerve is responsible for taste?
Vagus (X), Glossopharyngeal (IX), Facial (VII)
What are otoliths & what do they do?
"Ear stones"; calcium carbonate crystals. They are found in a gelatinous mass that surrounds some hair cells called the otolithic membrane; manipulates the cilia of hair cells when the head moves.
What are the possible pathways of sympathetic preganglionic & postganglionic neurons?
Preganglionic axon synapses with postganglionic neuron in sympathetic chain ganglion.
Preganglionic axon descends or ascends & synapses with a postganglionic neuron in a different chain ganglion.
Preganglionic axon passes through the chain ganglion & synapses with a postganglionic neuron in a collateral ganglion.
What effect does sympathetic nervous system activation have on individual cells?
Metabolic rate will increase & ATP consumption will increase
What occurs to the photoreceptors in dark adaptation?
Cones will receive less light and no longer function.
Rods will still function, but need time to slowly regenerate rhodopsin to function (as long as 40 min.).
How do we sense sound when sound waves enter into the ear?
Sound waves will cause the tympanic membrane, the auditory ossicles, &, by extension, the oval window to vibrate.
Vibration of the oval window will produce pressure waves that travel through the endolymph & perilymph.
The pressure waves will cause the basilar membrane to vibrate & cause the hair cells to bend.