Exam 3 Flashcards
1
Q
Acetylcholine
A
-released from cholinergic neurons
-major NT in peripheral nervous system and neuromuscular junction
-acts on 2 receptor subtypes to exert dif. effects (nicotinic and muscarinic)
2
Q
nicotinic receptors
A
-stimulatory
-ionotropic
3
Q
muscarinic receptors
A
-stimulatory or inhibitory
-metabotropic *Giq protein linked
4
Q
acetylcholinerase
A
-in the post-synaptic membrane
-converts ACh to choline and acetic acid
-choline taken up and combined with acetyl-CoA and repackaged
5
Q
biogenic amines- catecholamines specifically
A
-dopamine
-serotonin
-noradrenergic and adrenergic neurons
6
Q
dopamine
A
involved in reward and movement pathways
7
Q
noradrenergic and adrenergic neurons
A
-act on 5 types of metabotropic receptors (adrenergic receptors)
-alpha 1, 2, and beta 1,2,3
-major NT of sympathetic nervous system
8
Q
serotonin
A
-serotonergic neurons
-function in motor activity, sleep, food intake, reproductive behaviors, bone remodeling, and emotional states
9
Q
percentages of serotonin found across the body
A
-90% digestive tract
-8% found in platelets
10
Q
glutamate
A
-glutamatergic neurons
- predominant excitatory NT in CNS
11
Q
ionotropic
A
-excitatory post synaptic potential (epsp)
-AMPA and NMDA
-channel-linked
12
Q
AMPA
A
-non-selective cation channel
13
Q
NMDA
A
-Ca++ channel
14
Q
metabotropic
A
-8 subtypes
-use g-proteins and second messengers
-Gq, Gi
15
Q
GABA
A
-GABAnergic receptors
-predominant inhibitory NT in brain
16
Q
glycine
A
-glycinergic neurons
-one ionotropic receptor
(Cl- channel) IPSP of stabilizing current
-inhibitory
17
Q
what do neuropeptides mostly act as?
A
neuromodulators
18
Q
endogenous opioids
A
-(beta-endorphin, dynorphin, enkephalins)
-acts presynaptically to reduce painful stimuli reaching consciousness
-plays a role in eating, drinking, regulation of cardiovascular system, and in emotion
18
Q
substance p
A
-released from pain sensory neurons into the CNS
-appear to enhance painful stimuli perception
19
Q
peripheral nervous system divisions
A
-afferent
-efferent
20
Q
afferent division
A
somatic, visceral, special sensory
21
Q
efferent division
A
somatic motor, autonomic motor, sympathetic, parasympathetic, enteric
22
Q
autonomic nervous system
A
-involuntary/visceral
-maintain optimal internal environment
-sensory + motor
-3 divisions- sympathetic, parasympathetic, enteric
23
Q
enteric
A
-“the brain of the gut”
-can autonomously regulate primary and accessory digestive organs
-influenced by sympathetic and parasympathetic systems, but outside aren’t necessary
24
somatic nervous system effector organs
CNS -> skeletal muscle
25
autonomic nervous system effector organs
CNS -> smooth cardiac muscles, glands, or other cells
-uses preganglionic fiber, ganglion, then postganglionic fiber
26
what innervates most internal organs?
parasympathetic
27
where do parasympathetic fibers arise from?
-brain stem
-cranial nerves: III oculomotor, VII facial, IX glossopharyngeal, X vagus
-sacral spinal cord S2, S3, S4
28
what does the sympathetic directly regulate?
-cardiovascular system
-can indirectly affect other organs thru actions on blood vessels and release of epinephrine + norepinephrine from adrenal medulla
29
sympathetic division
thoracolumbar division- ganglia near spinal cord
30
parasympathetic division
craniosacral division- ganglia near or within wall of target organ
31
3 types of routes that can be taken by sympathetic axons
1. spinal nerves
2. sympathetic nerves
3. splanchnic nerves
32
spinal nerve route
1. preganglionic cell bodies in the lateral horn
2. myelinated axons exit the ventral motor root
3. they enter the sympathetic chain through the white ramus communicans
4. the preganglionic axon synapses with postganglionic neurons in the simple chain ganglia
5.unmyelinated axons exit ganglia thru grey ramus communicans and re enter the spinal nerves
33
sympathetic nerve route
1.preganglionic axons exit the ventral motor root
2.they enter the sympathetic chain thru the white ramus communicans
3.the preganglionic axon synapses with the postganglionic neurons and exit the ganglia thru a sympathetic nerve
34
splanchnic nerves route
1. preganglionic axons pass through sympathetic chain ganglia without synapsing to form splanchnic nerves
2. preganglionic axons then synapse with postganglionic neurons in prevertebral (collateral) ganglia. Post ganglionic neurons then send fibers to target organs (viscera)
35
innervation to adrenal gland route
1. preganglionic axons synapse directly with the cells of the adrenal medulla
2. embryologically, adrenal medulla is derived from same cells as post ganglionic ANS cells
3. medullary cells secrete epinephrine and norepinephrine; act as hormones supporting physical activity
36
sympathetic and parasympathetic organization
hypothalamus->brain stem->effector organs->spinal cord->effector organs
37
what do some sympathetic postganglionic neurons release?
acetylcholine
38
both branches use ACh to act on...?
muscarinic receptors in the ganglia
39
parasympathetic postganglionic neurons release ACh to act on...?
muscarinic receptors in the target organ
40
what do sympathetic postganglionic neurons usually release? and what does it act on?
-norepinephrine
-acts on either alpha or beta-adrenergic receptors
41
what is often also released from the postganglionic neuron?
-cotransmitters
-play a small role in effector response
42
what are cells of the adrenal medulla more like?
-sympathetic postganglionic neurons
43
sympathetic
-"fight or flight"
-stimulated by stress
-readies body for physical activity
-diffuse stimulation of organs
44
parasympathetic
-"rest and digest"
-coordinates processes needed for basic survival
-fine control over individual organ systems
45
do parasympathetic and sympathetic systems both work at the same time?
-both will always have some sort of activity at any given time
46
adrenergic receptors
alpha 1, 2, beta 1, 2, 3
47
alpha 1
-contractile effects
-norepinephrine/epinephrine on smooth muscle (blood vessels, urogenital, sphincters)
48
alpha 2
-inhibit norepinephrine release
49
beta 1
stimulatory effects of norepinephrine/epinephrine in the heart to increase heart rate and force of heart contractions
50
beta 2
-relaxing effects of predominately epinephrine on smooth muscle (gastrointestinal tract, urogenital, airway)
51
beta 3
-involved in lipolysis, glycogenolysis, and thermogenesis
52
blood-brain barrier contains
tight junction, astrocytes, and carrier mediated transport
53
sensory system
-parts of CNS that process
-neural pathway
-receptor
54
stimulus in a sensory system
-graded potential (receptor potential)
-action potential in afferent
55
sensory unit
single afferent neuron w/ all its receptor endings
56
receptive field
-area of body that when stimulated leads to activity in a particular afferent neuron
56
can receptive fields overlap?
receptive fields for nearby neurons overlap
57
signal transduction
-when a stimulus is transformed into an electrical response- sensory transduction
58
signal transduction receptors
-many receptors that each respond to a different stimulus
-some receptors more picky than others
-adequate stimulus is what activates a receptor
59
can receptors respond to stimuli other than their adequate stimulus?
-yes. but only if the signal is intense enough
-receptors can only code one sensation though
60
how does all sensory transduction begin?
-with opening or closing of an ion channel (direct or indirect)
61
where are ion channels located?
on distal tip of axon or on a receptor cell
62
receptor potential
graded potential produced by ion channels
63
the greater the graded potential is above threshold...
the greater the frequency of action potentials
64
the magnitude of graded potential depends on...
1.stimulus strength
2.rate of change of stimulus strength
3.adaptation
4.temporal summation of successive receptor potentials
65
coding
converting stimulus energy to a signal the CNS can interpret
66
coding signals
1. modality
2. intensity
3. location
4. acuity
67
location in coding
afferents follow unique pathways to specific areas of CNS
68
lateral inhibition
-enhances contrast
-utilized to greatest degree in pathways providing the most acuity
-not used as much in pain and temperature
-VERY IMPORTANT in visual activity
69
lateral inhibition- rapidly adapting receptors
-on-receptor
-off-receptor
70
sensory pathway
-bundle of parallel, three-neuron chains together
-1st order, 2nd order, 3rd order
71
specific ascending sensory pathways
carry one type of information
72
where does sensory information usually cross over to?
the opposite side of brain from where it originated
73
nonspecific ascending pathways
-utilize polymodal neurons
-control alertness and arousal
74
somatic sensation
sensations arising from skin
75
somatic sensation receptor thingies
1. meissners corpuscle
2. merkles corpuscle
3. free nerve ending
4. pacinian corpuscle
5. ruffini corpuscle
76
meissners corpuscle
-rapidly adapting mechanoreceptor
*touch and pressure
77
merkles corpuscle
-slowly adapting mechanoreceptor
*touch and pressure
78
free nerve ending
-slowly adapting, some nocireceptors, some thermoreceptors, some mechanoreceptors
79
pacinian corpuscles
-rapidly adapting mechanoreceptor vibration and deep pressure
80
ruffini corpuscle
slowly adapting mechanoreceptor- skin stretch
81
variety of mechanoreceptors
-hair bending
-deep pressure
-vibrations
-superficial touch
82
how mechanoreceptor works
1. mechanical tension in capsule
2. opening of ion channel
3. activation of neuron
83
rapidly adapting mechanoreceptors
touch, movement, vibration
83
slowly adapting mechanoreceptors
pressure
84
mechanoreceptors (proprioceptors)
-found in muscles, joints, tendons, ligaments, skin, vestibular system, vision
85
temperature + nociceptors
extremes in temperature activate pain receptors
86
0-35 degrees C (cold)
-nonselective cation channel
-menthol
87
30-50 degrees C (hot)
-nonselective cation channel
-capsaicin and ethanol
88
nociceptors
-intense mechanical deformation
-excessive heat or cold
89
chemical involved with nociceptors
-bradykinin
-prostaglandin
-histamine
-cytokines
-neuropeptides
90
what are glutamate and substance P related to?
transmission of pain info into CNS
91
why is pain in visceral organs perceived as pain in skin or skeletal muscles?
because visceral organ nociceptor afferents often synapse on same interneurons in spinal cord as skin nociceptor afferents
92
what do painful stimuli cause?
upregulation of receptors and hyperalgesia
93
anterolateral system
-carries pain and temp. info from skin to brain
94
dorsal column system
-receptors for body movement, limb positions, fine touch discrimination, and pressure
95
is there overlap in somatosensory cortex?
-yes
-sizes of areas can change with sensory experience
96
tarsal gland/meibomian glands
-specialized sebaceous glands produce sebum
Function: -forms junction between conjunctiva and skin
-prevents tears from flowing over eyelid margin
-a component of tear film on anterior surface of eye
-retards tear evaporation
97
lacrimal apparatus
-parasympathetic fibers of facial nerve VII
98
lacrimal gland
-innervated by parasympathetic fibers of facial nerve VII
Function:-moisten and lubricate the eye surface and eyelids
-produces tears
-kill bacteria
99
puncta + lacrimal canaliculi
-collect excess tears through puncta
100
lacrimal sac
-leads to nasolacrimal duct which opens into nasal cavity
101
conjunctiva
-very vascular
-thin mucous membrane
-lines posterior surface of eyelids+anterior surface of eyeball (non keratinized stratified squamous epithelium)
-2 PARTS
*palpebral conjunctiva
*ocular or bulbar conjunctiva
102
palpebral conjunctiva
-closely attached
-"inside" layer of eyelid (palebrae)
103
ocular or bulbar conjunctiva
-thin, translucent
-loosely attached to sclera by connective tissue
104
3 layers of the eye!
1. fibrous
2. vascular
3. nervous
105
fibrous layer
sclera and cornea
106
vascular layer
-choroid, ciliary body, iris
-contains most blood vessels of the eye
107
nervous layer
retina
108
sclera
-outside layer (muscle attachment)
-maintains eye shape
-protects internal structures of eye
-opaque (white color)
-dense collagenous connective tissue w/ elastic fibers
109
cornea
-transparent
-responsible for refraction of light
109
choroid
-thin layer
-darkly pigmented
-just deep to sclera
-very vascular
-function to nourish retina and absorb excess light
109
ciliary body
-produces aqueous humor that fills anterior chamber
-ciliary muscle
-smooth muscle
-controls lens shape
-ciliary processes attach to lens
109
iris
-colored portion of eye- suspended in aqueous humor between cornea and lens
-thin smooth muscle
-controls amt. of light entering eye
-pupil- opening
110
sphincter pupillae muscle
-parasympathetic
-controls pupil
111
contraction of sphincter pupillae muscle decreasing diameter uses
epinephrine
112
nervous layer of eye
1. neural layer
2. pigmented retina
113
neural layer
-contains sensory cells =, interneurons, support cells, and axons of optic nerve
114
pigmented retina
-outer layer
-pigmented simple cuboidal epi.
-separates retina from choroid
-reduces light scattering
115
compartments of eye
1.anterior compartment
2.posterior compartment
116
anterior compartment
-anterior to lens
-filled with aqueous humor
-produced by ciliary body
-returned to venous circulation thru Canal of Schlemm
-helps maintain intraocular pressure
-supplies nutrients to associated structures
-helps refract light
*Two Chambers:
1.anterior chamber
2.posterior chamber
117
anterior chamber location
between cornea and iris
118
posterior chamber location
between iris and lens
119
posterior compartment
-posterior to lens
-filled with vitreous humor
-majority of mass of eyeball
-98% water, amino acids, and hyaluronic acid
-helps maintain intraocular pressure
-helps hold lens and retina in place
-slightly refracts light
