10-25-13 (BIO 181) Flashcards
1
Q
entry of sound waves
A
outer ear
2
Q
amplification of sound waves (ENDS AT TYMPANIC MEMBRANE)
A
- Middle ear
3
Q
transduction of sound energy
A
- Inner ear
4
Q
- Sound travels in the form of
A
mechanical waves
5
Q
- Amplitude of waves
- Measured in Decibels (dB)
- Lowest detectable range = 0 dB
- Painful damage to the ear = 140 dB
- Normal speech = 60 dB
A
- Loudness
6
Q
- Frequency of waves
- Measured in Hertz (Hz)
- Normal human range = 20 to 20000 Hz
A
• Pitch
7
Q
- Sound waves hit ____ membrane and causes it to vibrate
* Sound waves must then must be amplified
A
tympanic
8
Q
- Vibration of tympanic membrane causes movement of ___ (bones) of the middle ear
- This is the first level of amplification
A
ossicles
9
Q
- Movement of ossicles causes movement of ____ _____
* Second level of amplification
A
oval window
10
Q
• Conversion of sound energy to action potentials occurs in cochlea of inner ear
A
TRANSDUCTION
11
Q
- Cochlea is separated from the middle ear via the ____ and ____ ___
A
Oval and Round windows
12
Q
- Cochlea is a closed structure that is composed of THREE fluid filled compartements
A
- Scala Vestibuli (perilymph)
- Scala Tympani (perilymph)
- Scala Media (endolymph)
13
Q
endolymph has a high concentration of
A
potassium ions
14
Q
- When sound waves hit the oval window, oval window vibrates
- This causes waves to occur in the perilymph of scala vestibuli
- Waves then travel to the scala tympani
- This causes movement of the round window
- Organ of Corti is located within the Scala Media of the cochlea (at the top of Basilar membrane)
- Contains HAIR CELLS
A
sound
15
Q
- Hair cells act as the the Receptor cells for sound
- Contain Stereocilia
• Have tips that are embedded in tectorial membrane
• Oriented short to tall - Surrounded by endolymph
- Stereocilia of hair cells are connected by protein bridges
A
sound
16
Q
- Mechanical stress (from sound) moves protein bridges and causes opening or closing of mechanically gated___ ____
A
K+ channels
17
Q
- Bend to tall stereocilia, channels open → ________ (potassium enters cell)
- Bend to short stereocilia,channels close → _______ (potassium does not leak into cell)
A
depolarization; hyperpolarization
18
Q
- Hair cells synapse on afferent axons of CN VIII
• Axons make up cochlear nerve
• One hair cell per one cochlear nerve fiber - Cochlear nerve enters brainstem
• Synapses with second-order neuron - Second-order neuron project onto the medial geniculate nucleus of thalamus
- Synapse on third-order neuron
- Third-order neuron projects onto auditory cortex
• Cranial Nerve VIII = Vestibulocochlear Nerve - Vestibular nerve branch for equilibrium
- Cochlear nerve branch for hearing
A
Neural Pathways for Sound
19
Q
- Olfactory receptor cells are one of a few neurons in the human body that are replaced continuously
- Receptor cells have cilia that project into the mucus that lines the nasal cavity
- Mucus contains Olfactory binding proteins which transport odorants to the receptor cells
A
Special Senses - Olfaction
Olfactory Receptor Cells
20
Q
- Air-borne chemicals must first dissolve in mucus
- The Olfactory binding proteins deliver olfactants (chemicals) to receptor cells
• Upon binding to the receptor, odorants trigger the production of cAMP (via the activation of a G protein)
• This ultimately causes a depolarization of the receptor cells - Once depolarized, receptors send their axons through the Cribriform plate (base of skull with holes) and towards the brain
A
olfactory signal transduction
21
Q
- Axons of receptor cells comprise CN I, the olfactory nerve
- Olfactory nerve then relays the information directly to the Olfactory Bulb in the brain
- Axons leaving olfactory bulb travel along olfactory tract to reach olfactory cortex
- Olfaction is the only sensory modality that has direct access to the cerebral cortex and DOES NOT have to go through the thalamus before reaching the cerebrum
A
Neural Pathway for Olfaction
22
Q
• Gustation provides information about taste and depends on chemicals in food (and liquids) that bind to ______
A
chemoreceptors
23
Q
- Taste receptors (or gustatory receptors) are distributed on tongue and portions of pharynx and larynx
- Clustered into ___ ____
A
taste buds
24
Q
- Located within epithelial projections (lingual papillae) on the superior surface of tongue
A
taste buds
25
lingual papillae contain 100 taste buds each
• Circumvallate papillae:
26
– lingual papillae contain five taste buds each
• Fungiform papillae:
27
– lingual papillae only provide friction
| – do not contain taste buds
• Filiform papillae:
28
• Taste buds contain
* Basal (stem) cells (regenerate themselves)
* Gustatory cells
• Extend taste hairs through taste pore
• Survive only 10 days before replacement
29
* Due to the presence of H+ in food
| * H+ binds to K+ channels and causes taste receptor cells to depolarize
* Sour
30
* Due to the presence of Na+ in food
* When salty foods are consumed, there is a huge driving force for Na ions to enter taste receptor cells, thereby causing them to depolarize
* Salty
31
* Due to the presence of orgaic molecules that have a structure similar to sucrose
* Binding of these “ligands” causes depolarization of the taste receptor cell
* Sweet
32
* Due to the presence of any nitrogen containing compound
| * Binding of these “ligands” causes depolarization of the taste receptor cell
* Bitter
33
* Release of neurotransmitters by receptor cell
| * Neurotransmitters generate action potentials in afferent fiber
• End Result of Taste Receptor Depolarization
34
* Taste receptor cells communicate to afferent neurons that travel via __________
CN VII, IX, and X
35
* CNs synapse onto to second-order neurons in the _____
brainstem
36
* Second-order neurons project to _____
thalamus
37
* Third-order neurons terminate in the _____ cortex in ____ lobe
gustatory; parietal
38
* Operates under voluntary, conscious control
* Seldom affects long-term survival
* SNS controls skeletal muscles
* Somatic Nervous System (SNS),
39
* Operates without conscious instruction and is involuntary (automatic)
* ANS controls visceral effectors
* Coordinates system functions: cardiovascular, respiratory, digestive, urinary, reproductive
* Autonomic Nervous System (ANS)
40
* Two divisions of the autonomic nervous system providing for a Dual innervation of effector organs
– Sympathetic nervous system
| – Parasympathetic nervous system
41
* Primary function—regulate organs to maintain homeostasis
Dual Innervation of the ANS
42
* Parasympathetic and sympathetic activities tend to ____ each other (and are active during different conditions)
oppose
43
* Most active during times of rest
| * Example – during digestion, slowing heart rate, etc.
• Parasympathetic nervous system
44
* Most active during stress or physical activity
| * Example – fight or flight response
• Sympathetic nervous system
45
• Both divisions of the autonomic nervous system innervate most effector ____
organs
46
```
* Effector organs include:
• Cardiac muscle
• Smooth muscle
• Glands
• Adipose tissue
• Consists of efferent pathways containing two neurons from CNS to effector organs
• Preganglionic neuron
• Postganglionic neuron
```
Anatomy of the ANS
47
• These neurons communicate with each other via synapses in the ____ ganglia
autonomic
48
• Sympathetic:
| * Emerges from ______ region of spinal cord (T1-L2)
thoracolumbar
49
• Parasympathetic:
* Emerges from the brain stem (specifically four out of the twelve cranial nerves) and the ____ region of the spinal cord
sacral
50
* Neurons of the SNS are linked together in the ____ ____
* Short preganglionic neurons to sympathetic chain
* Long postganglionic neurons from chain to effector organs
sympathetic chain
51
* Two exceptions to the general rule of anatomy
* Collateral ganglia— ganglia outside of the sympathetic chain that innervate ____ organs
* Suprarenal medulla-Innervation of the Adrenal medulla
digestive
52
• Preganglionic neuron communicates with postganglionic neuron in ____
ganglia
53
• ____ preganglionic neurons to ganglia near effector organ
Long
54
• ____ post ganglionic neurons from ganglia to effector organs
Short
55
• ______ neurons can originate in brainstem (specifically, some cranial nerves) or sacral spinal cord
Preganglionic
56
* Preganglionic fibers of Cranial nerves III, VII, IX, and X
| * Postgaglionic fibers innervate several target organs
• Cranial nerves (parasympathetic)
57
originate from segments S2-S4
• Preganglonic fibers of Pelvic nerves
• Postganglionic fibers innervate visceral organs in the abdominopelvic cavity
• Sacral Spinal nerves (parasympathetic)
58
• Primary neurotransmitters in the Autonomic Nervous System
• Acetylcholine
– Released by cholinergic neurons
• Norepinephrine and Epinephrin
– Released by adrenergic neurons
59
* Preganglionic neurons of the Sympathetic nervous system
| * Preganglionic AND Postganglionic neurons of the parasympathetic nervous systems
• Acetylcholine is released by:
60
* Postganglionic neurons of the Sympathetic nervous system
• Norepinephrine is released by
61
* Active during quiet, relaxed states
* Active in “rest and digest”
* Increase gastrointestinal activities
* Decrease heart rate and blood pressure
* reduces metabolic rate and promotes digestion
Parasympathetic Activity
62
* Fight-or-flight response
* Prepare for emergency, stress, and exercise
* Increase heart rate and blood pressure
* Decrease gastrointestinal and urinary functions
* increases alertness, metabolic rate, and muscular abilities
* Mobilize energy stores
* Pupillary dilation
Sympathetic Activity
63
* Both branches active
| * But at rest, Parasympathetic nervous system dominates
Tonic Activity at Rest
64
areas of the brain that regulate autonomic function
hypothalamus
pons
medulla oblongata
