a&p 1 - final Flashcards
1
Q
The commands for voluntary muscle
contraction start in a region of the brain
called
A
primary motor complex
2
Q
BLANK from the motor cortex initiates the commands
A
upper motor neurons
3
Q
nerve fibers decussate where? (upper motor neurons)
A
pyramids of medulla oblangata others at the spinal cord
4
Q
Originate from the anterior horn of the spinal cord?
A
lower motor neurons
5
Q
Lower motor neurons form? and reach the?
A
motor (anterior) roots of the spinal nerves; skeletal muscles
6
Q
Lower motor neurons can innervate?
A
One or many muscle cells (muscle fibers)
7
Q
What is a neuromuscular junction?
A
point of contact (synapse) where the axon terminal of a neuron meets a skeletal muscle cell
8
Q
Axon terminals (synaptic knobs) of motor neurons
contain?
A
synaptic vesicles = sacs filled with a
neurotransmitter called acetylcholine (=Ach).
9
Q
A skeletal muscle
consists of?
A
fasicles = muscle cells = muscle fibres
10
Q
The cell membrane of muscle
cells?
A
sarcolemma
11
Q
The sarcolemma has
invaginations called
junctional folds that contain?
A
nicotinic receptors for Acetylcholine
12
Q
Nicotinic receptors are?
A
ligand gated Na+ channels
13
Q
Deep invaginations of the sarcolemma?
A
T-tubules
14
Q
What do T-tubules do?
A
transmit AP deep inside muscle cell
15
Q
Skeletal muscle cells consist of BLANK surrounded by
BLANK
A
myofibrils; the sarcoplasmic Reticulum (SR)
16
Q
Myyofibrils consist of a sequence of BLANK made of BLANK of proteins (mostly actin and myosin)
A
sarcomeres; myofilaments
17
Q
Sarcomeres extends from?
.
A
one Z line to the next
18
Q
Sarcomeres consist of alternating?
A
I and A bands; responsible for striations
19
Q
I bands?
A
Light bands made of actin
20
Q
A bands?
A
dark bands made of myosin
21
Q
The zones of overlap are regions where Q and form Q under contraction
A
myosin and actin interact; cross bridges
22
Q
1 actin molecule (thin filament) looks like a…
A
bead necklace formed by two entwines strands of F actin
23
Q
Each F actin is formed by many
A
G actin
24
Q
Each G actin has an active site (where the head of
myosin binds during contraction to form a cross
A
active site (where the head of
myosin binds during contraction to form a cross bridge)
25
Thin filaments also contain 2 regulatory proteins
tropomyosin and troponin
26
What are thick myofilaments mostly made of?
myosin
27
What does myosin look like? What's it made of?
”golf club” formed by 2 entwined
polypeptides.
Each polypeptide has one tail and a globular head
28
What activates myosin head?
ATP hydrolysis
29
4 major phases of muscle contraction
Excitation; excitation-contraction coupling; contraction; relaxation
30
2 main types of cardiac muscle cells>
Autorrhythmic cells and Contractile (muscle cells or Cardiocytes)
31
Autorrhythmic cells?
SA node (built-in pacemaker sets off a
wave of electrical excitation
32
Contractile (muscle cells or
Cardiocytes)
Short, Y-shaped,
uninucleated, striated,
involuntary, connected by
intercalated discs (gap
junctions + desmosomes).
33
Cardiac muscle contraction?
AP travels down the T tubules-> Ca2+ enters from the extracellular fluid and from the Sarcoplasmic
reticulum. Calcium binds to troponin. The rest is like the events of skeletal muscle.
34
Chronotropic effects?
Change heart rate
35
Inotropic effects?
Change force of contraction
36
Smooth muscle reacts to?
autorhythmicity, hormones, CO2, O2, pH, temperature, stretch
37
Cell membrane of smooth muscle
contains
Calcium channels. dense bodies BUT no T-tubules
38
When stimulated, calcium increases in the sarcoplasm
because?
1. it comes from outside 2. it comes from SR
39
Where does Ca bind in smooth muscle?
calmodulin (instead of
troponin)
40
What enzyme activates myosin in smooth muscle?
myosin light chain kinase (MLCK)
41
Denervation atrophy
shrinkage of paralyzed
muscle when nerve remains
disconnected
42
Botulism
Type of food poisoning caused by a
neuromuscular toxin secreted by
the bacterium
Clostridium botulinum.
It blocks release of ACh causing
flaccid paralysis
43
Curare
blocks the nicotinic receptors
for acetylcholine causing flaccid
paralysis.
44
Myasthenia gravis
Autoimmune disease, antibodies attack the receptors in neuromuscular junction; lack of receptors causes weakness
45
Rigor Mortis
Hardening of the body starts ~4 hours after death, peaks at
about 12 hours and diminishes after 48-60 hours.
46
Why rigor mortis?
After death the SR deteriorates and releases Ca which binds to troponin active sites exposed, Actin and Myosin form cross bridges (peak at 12 h); since the person is dead no ATP is available (=step 13 does not
occur) à muscle remains contracted until actin and myosin deteriorate (48 – 60h)
47
5 Universal Characteristics of Muscle
1. Excitability 2. Conductivity 3. Contractibility 4. Extensibility 5. Elasticity
48
Twitch
quick cycle of contraction and relaxation when a single stimulus is applied at threshold or higher
49
Threshold
minimum voltage necessary to generate an AP in the muscle fiber and produce a contraction
50
Myogram
chart of a muscle twitch that shows the timing and
strength of a muscle’s contraction
51
Latent period
very brief delay between stimulus and contraction when excitation and excitation-contraction coupling are taking place
52
Contraction phase
Time when muscle generates tension (steps 10-13) . Period of time when cross bridges form
53
Relaxation phase
Time when tension declines to baseline (steps 14-18). Calcium is reabsorbed into the sarcoplasmic reticulum. Muscle tension goes to zero.
54
How are muscle responses graded?
frequency and intensity
55
Isometric contraction
No mvmnt; muscle develops tension but does not shorten
56
Isotonic concentric
Mvmnt; muscle shortens, tension remains constant
57
Isotonic eccentric
Mvmt; muscle lengthens while maintaining tension
58
Why is ATP necessary in muscle cells?
1. Activation of myosin head 2. Active transport to pump Ca (in and out) of the SR
59
What does ATP supply depend on?
Availability of oxygen and other organic energy sources
60
Aerobic respiration
Uses myoglobin; short, intense exercise, O2 is supplied by myoglobin but rapidly depleted
61
Phosphagen system
10-15s energy; energy comes from creatine phosphate (CP); uses no oxygen instead muscle borrows P from CP and gives it to ADP to make ATP; 1 ATP per CP
62
Anaerobic fermentation (glycolysis and lactic acid formation)
30-40s energy; glucose energy; doesn't use oxygen; produces 2 ATP per glucose along with lactic acid
63
Aerobic respiration
Hours of energy; energy comes from glucose and amino acids for first 30 minutes then fatty acids after 30 mi; 36 ATP per cycle
64
What is endurance?
Ability to maintain high-intensity exercise for more than 4-5 minutes
65
What is endurance determined by?
maximum oxygen uptake (VO2 max)
66
What determines VO2 max?
Age, sex, body size, training
67
What colour are slow-twitch muscles?
Red due to myoglobin
68
What are slow-twitch muscles used for?
Endurance b/c use oxidative ATP production for energy; has lots of capillaries, myoglobin, and mitochondria
69
What colour are fast-twitch muscles?
White b/c lacks mitochondria
70
What are fast-twitch muscles used for?
Quick responses; uses phosphagen system and anaerobic fermentation for energy; lots of CP, ATPase, and glycogen
71
Effect of endurance training?
slow twitch fibres will gain more mitochondria, acquire more capillaries, more RBCs, more oxygen transport
72
Benefits of endurance training?
enhances function of cardiovascular, respiratory, and nervous systems; improves skeletal strength and fatigue resistant muscles
73
Components of CNS?
Brain, spinal cord
74
Components of PNS?
Afferent and efferent peripheral nerves
75
Functions of nervous system?
sensory input; integration; motor output
76
What protects brain?
skull, meninges, and cerebrospinal fluid (CSF)
77
The meninges?
dura, arachnoid, pia mater
78
CSF?
watery cushion that products spinal cord and brain
79
What secretes CSF and where?
ependymal cells in the choroid plexus of ventricles in the brain and reabsorbed by arachnoid granulations
80
Where does CSF circulate?
subarachnoid space, ventricles and central canal of spinal cord
81
What are ventricles?
brain cavities filled with CSF; lined with ependymal cells; continuous with each other and with central canal
82
Where is lateral ventricle?
cerebral hemispheres
83
Where is third ventricle?
in diencephelon
84
Where is the fourth ventricle?
in hindbrain
85
What is interventicular foramen?
connects the lateral ventricles
86
What is cerebral aqueduct?
connects 3rd and 4th ventricles
87
Functions of CSF?
fills hollow cavities of brain and spinal cord; provides liquid cushion; nourishment; gets rid of waste
88
4 main regions of brain?
cerebrum; diencephalon; brainstem; cerebellum
89
What is cerebrum?
seat of intelligence; made of ridges (gyrus) and grooves (sulcus)
90
Lobes of cerebrum? (5)
frontal, parietal, occipital, temporal, insula (deep)
91
What is gray matter?
At surface cerebral cortex; deep in basal nuclei; composed of neuronal cell bodies
92
White matter?
deep; made of myelinated axons forming fibre tracts; ex. corpus collasum
93
Brodmann areas?
52 specialized cortical areas that make up about 75% of brain tissue
94
Prefrontal cortex?
judgement, planning
95
Primary motor cortex?
anterior to central sulcus; sends motor impulses to skeletal muscles in opposite side of body
96
Primary somatosensory pathway?
posterior to central sulcus; receives sensory impulses from opp. side of body
97
The afferent pathway general has chain of 3 neurons...
1st order: receives impulses 2nd order: decussate and take info to thalamus 3rd order: thalamus to primary somatosensory cortex
98
Primary visual cortex?
occipital
99
Primary taste?
parietal
100
Primary olfactory?
frontal and temporal
101
Primary auditory?
temporal lobe and insula
102
What makes up diencephelon?
epithalamus, thalamus, hypothalamus
103
What makes up epithalamus and what does it do?
pineal gland which synthesizes serotonin and melatonin
104
What makes up thalamus and what does it do?
contains about 23 nuclei that relay sensory impulse; transfers sensory impulses to correct part of cortex
105
Functions of hypothalamus?
Homeostasis (temp, thirst, hunger); major control centre for ANS (regulates adrenal medulla); controls endocrine functions (pituitary gland, ADH, oxytocin); emotional memory; sexuality;
106
Components of brainstem?
midbrain; pons, medulla oblangata
107
Components of midbrain?
two superior colliculi (visual reflexes); two inferior colliculi (auditory reflexes); two pigmented nuclei: substantial nigra and red nucleus
108
What does the pons contain?
ascending and descending fibre tracts that relay signals from cerebrum to cerebellum; nuclei of cranial nerves: V, VI, VII
109
What does medulla oblongata contain?
It's continuous with spinal cord and has pyramids (site of decussation); nuclei of cranial nerves (VIII - XII); nuclei of basic visceral motor (autonomic centers) --> respiration, heart beat, blood pressure; nuclei cuneatus and gracilis (sensory info); nuclei of reticular formation (pain modulation, habituation, alertness)
110
What does cerebellum contain?
2 hemispheres connected by vermis; balance and motor coordination, posture and equilibrium, memory of learned motor skills
111
Cranial nerve I
Olfactory (S) --> smell
112
Cranial nerve II
Optic (S) --> vision
113
Cranial nerve III
Oculomotor (M) --> eye mvmnt and pupillary constriction
114
Cranial nerve IV
Trochlear (M) --> eye mvmnt (innervates superior oblique)
115
Cranial nerve V
Trigeminal (B) --> S: sensitivity of face M: mvmnt of muscles of mastication
116
Cranial nerve VI
Abducens (M) --> lateral eye mvmnt
117
Cranial nerve VII
Facial (B) --> S: taste M: facial muscles
118
Cranial nerve VIII
Vestibolocochlear (S) --> hearing, balance
119
Cranial nerve IX
Glosso-pharyngeal (B) --> S: taste, touch, pressure, temp from posterior tongue and outer ear M: salivation, swallowing, gagging
120
Cranial nerve X
Vagus (B) --> S: taste, sensations of hunger, fullness, and gastrointestinal discomfort M: swallowing, slows down heart rate, causes bronchoconstriction, increases GI secretions and motility
121
Cranial nerve XI
Accessory (M) --> head, neck, and shoulder mvmnt
122
Cranial nerve XII
Hypoglossal (M) --> tongue mvmnts
123
Functions of spinal cord?
1. conduct info 2. neural integration 3. locomotion 4. reflexes
124
Anatomy of spinal cord?
extends from medulla oblongata to conus medullaris (T12)
125
Regions of spinal cord?
Cervical, thoracic, lumbar, sacral (regions are named for areas that they emerge)
126
Where do nerves of upper and lower limbs emerge?
cervical and lumbar enlargements
127
Cauda equina?
group of nerves originating in conus medallaris; innervate pelvic organs and lower limbs
128
Filum terminale
long filament of connective tissue, attaches the spinal cord to coccyx inferiorly
129
What is epidural space?
space between dura mater and vertebral bones
130
Subarachnoid space?
space between arachnoid and Pia mater where CSF circulates
131
Lumbar puncture (spinal tap)?
needle inserted between L3 and L4 to remove sample of CSF from subarachnoid space
132
What is grey matter?
internal, H-shaped, site of integration of signals
133
What are 3 zones of grey matter?
1. dorsal horns 2. lateral horns 3. ventral horns
134
Dorsal horns?
somatic sensory and visceral sensory receptors
135
Lateral horns?
visceral motor --> sends signals to visceral effectors (involuntary)
136
Ventral horns?
somatic motor --> sends signals to voluntary effectors
137
What is in centre of grey matter?
central canal which is lined with ependymal cells that synthesize CSF
138
What is white matter?
site of transmission of ascending and descending signals between spinal cord and brain; mostly myelinated axons; bundles of axons are arranged in 3 pairs called columns or funiculi (ventral, lateral, dorsal); columns consists of tracts
139
How are tracts of white matter divided?
ascending and descending tracts
140
ALS?
progressive degeneration of motor neurons in spinal cord and brain; affects voluntary effectors
141
Spinal cord injury?
Paraplegia (transection between T1 and L1) and quadriplegia (transection of cervical region)
142
Spina bifida?
congenital defect due to low maternal folic acid; lumbar vertebrae fail to develop which affects dev. of spinal cord; causes lack of bladder and bowel control and paralysis of lower limbs
143
What is a nerve?
Cordlike structure that contains anywhere from few axons to a million axons
144
Dorsal and posterior roots are?
sensory
145
Cell bodies of sensory (unipolar) neurons are in?
sensory (dorsal) ganglion
146
Cell bodies of motor neurons are in?
Ventral horns of spinal cord
147
Ventral roots are?
anterior and motor
148
Immediately after emerging from intervertebral foramen, each spinal nerve divides into:
dorsal/posterior ramus or ventral/anterior ramus
149
Posterior rami innervate?
skin, muscles, and joints on posterior side of the head and the dorsum
150
Anterior rami innervate?
skin of trunk and limbs; muscles of trunk and limbs
151
From T1 to L2, the anterior rami give off a pair of...
communicating rami which connect sympathetic chain ganglia alongside the spine
152
What are nerves covered by?
epineurium
153
Perineum of nerves?
middle layer that divides nerves into bundles of axons called fasicles
154
Endoneurium of nerves
inner layer surrounding individual axons
155
MS?
demyelinating nerve disorder of CNS
156
Guillan Barre syndrome
demyelinating nerve disorder of PNS
157
What is a nerve plexus?
except in thoracic region; anterior rami branch and anastomose (merge) repeatedly to form five weblike nerve plexuses
158
Cervical plexus?
formed by ventral rami C1-C4, innervate back of head, neck, ear, shoulder
159
Main nerve of cervical plexus?
phrenic nerve which innervates diaphragm
160
Brachial plexus?
C5-T1 which gives rise to nerves of upper limb
161
Main nerves of brachial plexus?
ulnar, radial, median, axillary
162
Lumbar plexus?
innervates abdominal wall and thigh
163
Main nerves of lumbar plexus?
femoral and obturator
164
Sacral plexus?
innervates pelvic structures, perineum, and lower limb
165
Main nerve of sacral plexus?
sciatic nerve which splits into tibial and common fibular nerve
166
Main nerve of coccygeal plexus?
coccygeal nerve
167
What is dermatome?
zone of skin which is innervated by sensory branches of spinal nerves (except C1)
168
Where are dermatomes of upper extremity connected?
sensory branches C5-T1
169
Where are dermatomes of lower extremity connected?
sensory branches L1-S1
170
What is a reflex?
quick, involuntary, stereotyped action in response to changes within or outside the body
171
How do spinal reflexes work?
they're initiated without brain input
172
Patellar tendon reflex arch?
prevents excessive stretching of quadriceps
173
Flexor and crossed extension reflexes
maintains balance by causing flexion of an injured ipsilateral limb and extension of contralateral limb
174
Divisions of ANS?
parasympathetic and sympathetic
175
What is the ANS?
visceral motor division of PNS = involuntary component
176
What does ANS control?
glands, smooth muscle, cardiac muscle
177
What is important centre of ANS control?
hypothalamus
178
Origins of preganglionic neurons of sympathetic?
1. thoracic segment 2. lumbar segments
179
Origins of preganglionic neurons of parasympathetic?
1. cranial segments 2. sacral segments
180
Types of sympathetic autonomic ganglia?
1. lateral to vertebral column (paravertebral sympathetic ganglia --> thoracic, lumbar)
2. anterior to vertebral columns: prevertebral sympathetic ganglia (celiac ganglion, superior mesenteric ganglion, inferior mesenteric ganglion)
181
Preganglionic and postganglionic neurons of sympathetic?
preganglionic are called white communicating rami and postganglionic are grey communicating rami which reach target organ
182
Preganglionic sympathetic neurons length?
short
183
Postganglionic sympathetic neurons lengths?
long
184
Types of parasympathetic autonomic ganglia?
1. near target organ (pterygoid ganglion, ciliary ganglion, submandibular ganglion, otic ganglion)
2. within target organ (terminal ganglion in trachea, lungs, abdominal organs
185
Preganglionic parasympathetic neurons length?
long
186
Postganglionic parasympathetic neurons length?
short
187
Effect of sympathetic?
widespread effect; fight or flight; prepares body for action, uses energy; "E" division: exercise, excitement, embarrassment, emergency
188
Effects of parasympathetic?
local effect, maintains daily body functions and conserves energy; "D" division: digestion, defecation, diuresis
189
What does parasympathetic not effect?
liver (glycogen stores) and adipose cells
190
2 main routes of sympathetic innervation to organs?
1. thoracic 2. lumbar
191
How does thoracic route of sympathetic work?
preganglionic fibres synapse at paravertebral ganglia; postganglionic go to (via carotid plexus): head, iris of eye (midryasis), nasal + salivary glands (decrease secretions); go to (via cardiac and pulmonary plexuses): effectors in thorax, heart (increase HR), lungs (bronchodilator); via spinal nerves to effectors in skin (blood vessels, piloerector muscles, sweat glands)
192
How does lumbar route of sympathetic work?
preganglionic fibers synapse at prevertebral ganglia. Postganglionic
fibers go via splachnic nerves to effectors in abdominal cavity:
celiac ganglion (liver, pancreas, stomach)
superior mesenteric (small/large intestine)
inferior mesenteric (intestine, rectum, genitals)
aorticorenal (kidneys, bladder, rectum)
193
2 main routes of parasympathetic innervation to organs?
1. cranial 2. vagus nerve (X)
194
How does cranial route of parasympathetic work?
preganglionic fibres are 3 cranial nerves: occulumotor III, facial VII, and glossopharyngeal IX that supply all parasympathetic innervation to the head --> synapse at ciliary ganglion, pterygopalatine + submandibual and otic ganglion respectively
postganglionic fibres go to target organ: ciliary --> iris (myosis)
pterygopalatine --> lacrimal (tears)
submandibular--> salivary (secrete)
otic --> parotid salivary (secrete)
195
What has no parasympathetic innervation?
blood vessels, piloerector muscles, sweat glands, adrenal medulla
196
How does vagus nerve route of parasympathetic work?
cardiac plexus, pulmonary plexus, and esophageal plexus, which synapse at terminal ganglia in thoracic, abdominal viscera, and the kidneys; celiac ganglion and abdominal aortic plexus which synapse at terminal ganglia in liver, stomach, pancreas, and intestine
197
How does sacral route of parasympathetic work?
preganglionic pelvic splanchnic nerves from inferior hypogastric plexus that synapse at terminal ganglia of pelvic organs (urinary bladder, reproductive organs, rectum)
198
Myosis/mydriasis
constriction/dilation of iris in response to light
199
Peristalsis
mvmnt of gastrointestinal tract, also reflex for defection
200
Baroreflex (sympathetic response)
adjust blood pressure and cardiac centre adjusts by controlling HR and vasomotor tone --> vasoconstriction in response to high rate of sympathetic nerve firing and vasodilation in response to low rate of sympathetic nerve firing
201
Components of visceral (autonomic) reflexes?
1. receptor 2. afferent neuron 3. interneuron 4. efferent preganglionic neutron 5. efferent postganglionic neuron 6. effector
202
What kind of neurotransmitter do symp pregangionlic neurons contain?
Acetylcholine (cholinergic)
203
What kind of neurotransmitter do symp postgangionlic neurons contain?
norepinephrine (NE) adrenergic
204
What breaks down catecholamines?
MAO
205
Neurotransmitters of pre and postganglionic neurons of parasympathetic?(one word)
acetylcholine (Ach)
206
Adrenergic receptors?
a1(vasoconstriction), a2(decrease smooth muscle contraction), b1(excitatory response in heart), b2 (bronchodilator)
207
Cholinergic receptors?
nicotinic (depolarization) found in all autonomic ganglia; muscarinic (slow heart, and cause smooth muscle contraction) found in smooth muscle, cardiac muscle and glands
208
2 main cell types of CNS?
glial cells and neurons
209
Glial cells?
more of them than neurons; bind to neurons to protect, support, and nourish them; can multiple unlike neurons
210
Function of astrocyte (CNS)?
blood brain barrier
211
Function of ependymal cells (CNS)?
makes CSF
212
Function of oligodendrocyte? (CNS)
makes myelin
213
Function of microglial cell? (CNS)
gets rid of bacteria
214
Function of satellite cell? (PNS)
regulates nutrition and waste
215
Function of neurolemmocyte? (PNS)
myelin
216
Multipolar neuron?
most neurons; motor neurons and interneurons
217
Unipolar neurons?
include all sensory neurons; form dorsal roots of spinal nerve
218
Bipolar neurons?
sensory neurons in special sense organs
219
Anaxonic neurons?
regulate local electrical activity of adjacent neurons
220
Regions of neurons?
dendrite, cell body (soma), axon hillock, axon, nodes of ranvier, axon terminals
221
Dendrite?
conduct impulses towards the body
222
Cell body/soma?
nucleus, integrates info
223
Axon hillock?
region in soma where axon originates
224
Nodes of ranvier?
gaps with no myelin
225
Axon terminal?
synaptic knobs which contain neurotransmitters; contact another neuron or an effector
226
Synapse?
structure that allows neuron to pass an electrical or chemical signal to another neuron (or to an effector)
227
Presynaptic neuron?
synoptic knob containing synaptic vesicles with neurotransmitters
228
Synaptic cleft?
space in between presynaptic and postsynaptic neuron
229
Postsynpatic neuron?
membrane that contains receptors and ligand-gated ion channels that respond to neurotransmitter
230
2 main functions of neurons?
excitability and conductivity
231
What is excitability?
Ability of neuron to be stimulated
232
When a neuron is stimulated, the impulses result in
local potentials or graded potentials
233
2 types of local potentials?
IPSPs (inhibitory postsynaptic potentials) and EPSPs
234
What determines if depolarization of axon hillock leads to axon hillock reaching potential?
summative effect of ISPS and ESPS; if ISPS dominates nothing happens but if ESPS occurs it goes through cycle
235
Absolute refractory period
impossible to stimulate neuron to fire again during AP and shortly after
236
Relative refractory period
very difficult to stimulate neuron to fire again during AP and shortly after
237
Conductivity?
Ability of neurons to carry an AP along the axon; once AP is generated, there is unidirectional wave of propagation of AP mediated by voltage gated Na+ and K+ channels
238
Events at a synapse?
1. AP arrives at axon terminal
2. Ca enters
3. neurotransmitter released and binds to receptor on postsynaptic cell
4. Graded or local potential generated
239
4 main types of neurotransmitters?
acetylcholine, amino acids, monoamines, neuropeptides
240
Effect of epinephrine/norepinephrine?
sympathetic; fight or flight; adrenergic synapses
241
Effect of glutamate?
Main excitatory neurotransmitter in the brain
242
Effect of aspartate
Main excitatory neurotransmitter in the spinal cord
243
Effect of GABA?
Main inhibitory neurotransmitter in the brain
244
Effect of glycine?
Main inhibitory neurotransmitter in the spinal cord
245
Norepinephrine dual effects?
excitatory (raises blood pressure), inhibitory (causes bronchodilation)
246
Serotonin dual effects?
excitatory (mood), inhibitory (sleep, nociception)
247
Dopamine dual effects?
excitatory (reward, motivation), inhibitory (controls motor function)
248
Acetylcholine dual effects?
excitatory (promotes digestion), inhibitory (lowers heart rate)
249
Parkinson's disease?
less dopamine = less inhibitory signals = more stimulation
treatment: dopamine precursor to increase levels
250
Mechanisms that stop signals?
a)presynaptic cell stops releasing neurotransmitter b) reuptake: synaptic knob reabsorbs neurotransmitter by endocytosis
c) neurotransmitter is broken down by an enzyme, ActE or MAO
251
What does learning increase?
Number of dendritic spines
252
Purpose of nerve sensory receptor?
Transduction, conversion of one form of energy into nerve signals
253
What 3 nerves are involved in gustation?
facial nerve (VII), Glossopharyngeal (IX), vagus nerve (X)
254
All pathways go to thalamus first except?
olfactory and equilibrium
255
3 regions of ear?
1. external ear 2. middle ear 3. inner ear
256
What does external ear contain and function?
auricle (pinna) is entrance to auditory/external ear canal which has ceruminous and sebaceous glands --> direct soundwaves to tympanic membrane (eardrum)
257
What does middle ear contain and function?
a. tympanic membrane (eardrum) which seps. external and inner ear; sound waves cause vibration
3 auditory ossicles: malleus, incus, stapes
2 muscles: tensor tympani, stapedius
internal auditory tube: connects middle ear to nasopharynx; equalize air pressure; normally closed but swallowing or yawning opens it
258
What is tympanic reflex?
protective mechanism initiated by loud sounds; causes contraction of these muscles to reduce the amount of motion of ear ossicles; also helps coordinating speech and hearing
259
What does inner ear contain and function?
consists of hollow bony structures filled with endolymph
260
Inner ear contains organs that detect?
equilibrium (semicircular canals and vestibules), hearing (cochlea)
261
Components of semicircular canals?
3 canals filled with endolymph; which contain crust ampullaris with hair cells; gelatinous cap (capula)
fnc: detect rotary mvmnts in 3 planes
262
Components of the vestibule?
has two chambers: saccule (anterior) and utricle (posterior); the macula sacculi and utriculi contain hair cells with stereocilia covered by gelatinous cap with otoliths
263
What does vestibule detect?
orientation of the head(when it's stationary); linear acceleration
264
What is cochlea?
spiral shaped structure containing 3 fluid-filled chambers: Scala vestibuli (superior, contains oval window), Scala media (contains organ of corti), Scala tympani (inferior, contains round window)
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What is organ of corti?
spiral organ that contains hair cells that lie on a basilar membrane and are covered by a tectorial membrane
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What's the hearing pathway?
1. sound waves enter auditory canal and cause vibration of tympanic membrane
2. vibration of auditory ossicles: hammer, anvil, stapes
3. increased pressure in perilymph causes vibration of oval window
4. mvmnt of endolymph causes mvmnt of the basilar membrane and the hair cells of the organ of corti
5. stereocilia on the hair cells bend --> action potential for hearing starts
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The nerve signals produced in the Organ of Corti are carried by what nerve?
by cochlear nerve which joins vestibular nerve to form vestibulocochlear nerve
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What is loudness?
perception of sound intensity
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What is conductive deafness?
blockage of auditory canal; damaged tympanic membrane; otitis media; otosclerosis (fusion of auditory ossicles that prevents their free vibration)
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What is sensorineural deafness?
damage of hair cells or other hearing NS elements
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They eye is divided into...
1. anterior segment (filled with aqueous humour) subdivided by anterior and posterior chamber
2. posterior segment (filled by vitreous humour)
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Optical components?
transparent elements that admit light, refract light rays, and focus images on retina: cornea, aqueous humour, lens, vitreous humour
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3 layers of the eye?
1. fibrous tunic (sclera, cornea)
2. vascular tunic: iris, dilator pupillae, sphincter pupillae; ciliary body (secretes aqueous humour)
3. neural tunic: part of diencephelon
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What cells does retina contain?
rods, cones, ganglion cells, bipolar cells
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Important elements of fundoscopy (eye exam)?
blood vessels; macula lutea (fovea centralis --> site of sharpest vision); optic disc (blindspot)
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Accessory structures of the orbit?
1. eyelids (palpebrae): block foreign objects, help with sleep, blink to moisten --> consists of obicularis oculi muscle and tarsal plate
2. tarsal glands secrete oil that reduces tear evaporation
3. lacrimal glands: produce tears to wash and lubricate eye, deliver O2 and nutrients, prevent infections
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How do tears flow?
through lacrimal punctum to canaliculi to lacrimal sac then into nasolacrimal duct emptying into nasal cavity
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Six extrinsic muscles?
lateral rectus, medial rectus, superior rectus, inferior rectus, inferior oblique, superior oblique
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Strabismus?
Misalignment of the eyes often due to an imbalance of the extraocular muscles
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What three reflexes are required for
near-point vision?
a) convergence of eyes
b) constriction of pupil
c) accommodation of lens
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Focal point?
the closest an object can be to the eyes and still come into focus
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Stereoscopic vision
depth perception
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Glaucoma?
increase of intraocular pressure due to obstruction in the outflow of aqueous humour --> blindness
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Cataracts?
clouding of the lens; induced by diabetes, smoking, drugs, UV light, and certain viruses
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Myopia?
myopic eye is longer than normal; as result light ray focuses in front of retina instead of on it
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Hyperopia?
hyperopic eye is shorter than usual so light focuses behind retina
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Astigmatism?
blurred vision due to unequal curvatures of the lens or cornea; distorts vision for both near and far objects
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Two optic nerves combine to form what?
optic chiasm which splits to form optic tracts
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