Unit 6: ANS and Somatic Sensory Division Flashcards
The ANS controls which structures?
Glands, smooth muscle, and cardiac muscle
Describe a visceral reflex arc and give an example
Imbalance or sensation detected within the body (organs), afferent neurons send message to spinal cord/brain where information is integrated, efferent neurons send message to effector in response
Example: vomiting, swallowing, contracting walls of hollow organs, dilation of pupil
What is the difference between the parasympathetic and sympathetic nervous systems
The sympathetic nervous system prepares the body for physical activity - “fight or flight”
The sympathetic nervous system calms the body and allows for rest - “rest and digest”
What is the difference between somatic and autonomic pathways
Somatic NS controls voluntary movements involving skeletal muscle
Autonomic NS controls involuntary movements involving smooth and cardiac muscle and glands
Somatic NS detects sensory stimuli (smell, taste, touch, etc.)
Autonomic NS detects sensory stimuli within (change in blood pressure, pH, etc.)
Somatic NS always causes excitatory response (acetylcholine)
Autonomic NS can be excitatory or inhibitory (acetylcholine or norepinephrine)
How many neurons are involved in the ANS neural pathways? What are they called?
2 neurons
Preganglionic and Postganglionic
Where are the ganglia located in the ANS neural pathways?
Central neuron between pre and post neurons
Where do preganglionic cells originate in the sympathetic NS?
Thoracolumbar (T1 - L2)
Where do preganglionic cells originate in the parasympathetic NS?
Brain stem or sacrum
Sympathetic NS has a variety of pathways which allow for
Convergence and Divergence = Widespread effect
The Sympathetic NS ganglion is called the
sympathetic chain ganglia
The Parasympathetic NS has long neurons which allow for _________
targeted effects
The terminal ganglia are located _________ in the Parasympathetic NS because
At the effector because the post ganglionic neuron is very short
What is the enteric NS
Digestive tract’s nervous system
Describe the Enteric NS
Neurons line the walls of the GI tract
Has own reflex arc (is not involved w/ CNS)
Regulates the secretions and movement of muscles in the viscera
What neurons in the ANS are cholinergic?
Nicotinic
At synapse between pre AND post neurons in parasympathetic AND sympathetic NS
Muscarinic
On all parasympathetic NS target cells and some sympathetic NS target cells
Define cholinergic
Release acetylcholine (ACh)
Define adrenergic
Release norepinephrine
What neurons are adrenergic and where do they originate?
Adrenergic
Sympathetic NS target cells
Nicotinic receptors are
Excitatory
Muscarinic receptors are
Excitatory or inhibitory
Adrenergic receptors are
Excitatory or inhibitory
Define dual innervation
Means an organ gets input from both the sympathetic and parasympathetic nervous systems
What is an example of how the parasympathetic and sympathetic nervous systems can be antagonistic
When the sympathetic NS raises the heart rate, the parasympathetic NS works to make sure the heart rate does not increase too much
SNS dilates pupil and PSNS constricts pupil/ brings back to normal
What is an example of how the parasympathetic and sympathetic nervous systems can be cooperative
Reproductive and urinary systems effected cooperatively by SNS and PSNS
Erection of penis is due to vasodilation from parasympathetic NS stimulation
Ejaculation is due to stimulation through sympathetic nerves
Urge to urinate is promoted by constriction of bladder (PSNS) and encouraged by SNS which increases tone of the bladder muscles
How does the sympathetic nervous system affect the cardiovascular system
Increase heart rate
Increase BP
Vasoconstriction of vessels
How does the parasympathetic nervous system affect the cardiovascular system
Decrease heart rate
Decrease BP
How does the sympathetic nervous system affect the respiratory system
Increase ventilation rate
Dilate bronchi
How does the parasympathetic nervous system affect the respiratory system
Decrease ventilation rate
Constrict bronchi
How does the sympathetic nervous system affect the nervous system
Dilate pupils
How does the parasympathetic nervous system affect the nervous system
Constrict pupils
How does the sympathetic nervous system affect blood nutrient levels?
Increase glucose
Increase fatty acids
How does the sympathetic nervous system affect the endocrine system
Secretes adrenaline
Lowers insulin levels
How does the parasympathetic nervous system affect the endocrine system
Increase insulin levels
How does the sympathetic nervous system affect the digestive system
Decrease peristalsis
Decrease salivation
Contract sphincters
Decrease enzyme secretions
How does the parasympathetic nervous system affect the digestive system
Increase peristalsis
Increase salivation
Relax sphincters
Increase enzyme secretions
How does the sympathetic nervous system affect the urinary system
Relax the bladder
How does the parasympathetic nervous system affect the urinary system
Contract (empty) bladder
How does the sympathetic nervous system affect the cutaneous tissues
Contract arrector pili
Increase sweat production
How does the parasympathetic nervous system affect the cutaneous tissues
Decrease sweat gland secretion
How does the sympathetic nervous system affect the reproductive system
Ejaculation
How does the parasympathetic nervous system affect the reproductive system
Erection
What are transducers and what do they do?
Sensory receptors which convert stimuli to electrochemical activity
What are the 3 ways sensory receptors are classified?
By modality (form)
By origin of stimuli
By distribution
Give examples of Modality sensory receptors
Chemoreceptors, thermoreceptors, nociceptors, mechanoreceptors, photoreceptors
Give examples of origins for stimuli for sensory receptors
Interoreceptor (within)
Proprioceptor (position/ movement of body)
Exteroce[tpr (external)
What are the 2 types of distribution for sensory receptors
General/Somesthetic (widely distributed)
Special senses (taste, sight, touch, hearing, smell)
How many neurons are involved in the Somesthetic (general) sense pathways? What are they called?
3 neurons
First order neuron
Second order neuron
Third order neuron
What is the job of a first order neuron? Where is it located in the head? In the rest of the body?
Afferent = detect stimuli
Head = Cranial nerves to pons & medulla
Body = Spinal nerves to dorsal horn of spinal cord
Touch, pressure, and proprioception are delivered on _____, ______, and ______ axons
Fast, large, and myelinated
Temperature reception is delivered on _______, _______, and _______ axons
small, slow, and unmyelinated
What is the job of a second order neuron? Where does this message end?
Transmit message to opposite side of the medulla or spinal cord
Ends in thalamus
What is the job of a third order neuron? Where does this path end?
Extends from thalamus to the primary somesthetic cortex of the parietal lobe
Where is the primary somesthetic cortex
Parietal lobe
Somatic pain comes from
Surface (skin, muscle, joints)
Visceral pain comes from
Within (stretch of organs, chemical irritants, damage, etc.)
Describe fast pain and how fast does it travel?
Sharp, local, stabbing pain
Travels at 30 m/s along myelinated fibers
Describe slow pain and how fast does it travel?
Dull, long-lasting, diffused pain
Travels at 2 m/s along unmyelinated fibers
Nociceptors are found everywhere except
The brain
What are nociceptors
Pain receptors
What are the 5 primary taste sensations?
Sweet, sour, bitter, umami, salty
What stimulates the sweet taste? How?
Sugars/glucose
Bind to receptors
What triggers the bitter taste? How?
Alkaloids
Bind to receptors
What triggers the umami taste? How?
Glutamates
Bind to receptors
What triggers the sour taste? How?
Acids
Depolarize cells directly
What triggers the salty taste? How?
Sodium
Depolarize cells directly
Which cranial nerves innervate taste buds?
Facial (7), Glossopharyngeal (9), Vagus (10)
Where is taste perceived in the cerebrum?
Postcentral gyri
What is found within the olfactory foramina?
Olfactory nerves
The cribriform plate is found on the __________ bone and contains olfactory foramina
Ethmoid
Olfactory sensors adapt _______
Quickly
How long do olfactory neuron survive for?
60 days
What is the olfactory mucosa?
Made up of receptor cells which have 20 cilia
Define pinna and its function
AKA auricle
Directs air vibrations down external auditory meatus
Describe how sound waves travel through the ear to be processed by the brain
Sound waves enter at pinna and are directed down external auditory meatus
Tympanic membrane vibrates
Auditory ossicles vibrate
Cochlear membrane vibrates which activates hair cells, ion channels open to depolarize
Sound perceived by primary auditory cortex in temporal lobe
Where is the primary auditory cortex?
Temporal lobe
What are the 3 regions of the ear?
External, middle, and inner
What structures are in the outer ear?
Auricle, tympanic membrane
What structures are in the middle ear?
Auditory ossicles (Malleus, Incus, Stapes)
What structures are in the inner ear?
Cochlea, Semi-circular canals, eustachian/auditory tube, and vestibulocochlear nerve (8)
What is the purpose of the eustachian/auditory tube?
Connect middle ear to pharynx
Relieves air pressure in ear
What are the passageways from the inner ear to the temporal lobe called?
Bony labyrinth and membranous labyrinth
Define stereocilia
Hair cells which stimulate ion channels to open
Stereocilia are bathed in ______
potassium
When the cochlear membrane moves, it causes
Stereocilia to open ion channels, which depolarizes and releases neurotransmitters
Semicircular canals contain _______ which alert the body of orientation
crista ampullaries (gelatinous membranes around hair cells)
Equilibrium is maintained by messages through the ______ nerve from the ear to the ________
Vestibulocochlear
Cerebellum and pons
Define conjuctiva
Sensitive and vascular mucous membrane that lines eyelid and eyeball
Define lacrimal apparatus
Produces tears which wash away foreign particles
What are the layers of the eye from outer to inner?
Fibrous
Vascular
Sensory
What does the fibrous layer of the eye contain?
Sclera and cornea
What does the vascular layer of the eye contain?
Choroid, cilliary body, iris
What does the sensory layer of the eye contain
Retina and optic nerve
Visual input from the eyes is perceived in the _____ lobe
Occipital
What are the 2 humors of the eye and where are they located?
Aqueous (between cornea and lens)
Vitreous (between lens and retina)
What are the 4 optical components? What do they all have in common?
Cornea
Aqueous humor
Lens
Vitreous humor
All are transparent and focus light on retina
Define emmetropia
Ability to focus easily on distant objects because of parallel light waves
Define hyperopia
Farsighted
Define myopia
Nearsighted
What happens when looking at a nearby object?
Convergence of eyes
Constriction of pupil
Change of lens shape