Lab Practical 3 Flashcards
1
Q
gray scale; stimulated in low light
A
rods
2
Q
color; stimulated in high light
A
cones
3
Q
What are the 3 types of cones?
A
- red
- green
- blue
4
Q
The eye is divided into what 2 sections?
A
- anterior
2. posterior
5
Q
contains photoreceptors for vision
A
retina
6
Q
the colored portion of the eye
A
iris
7
Q
this structure changes shape to focus light on the retina
A
lens
8
Q
the opening in the iris through which light passes
A
pupil
9
Q
the iridescent portion of the choroid layer found in “nocturnal” animals
A
tapetum lucidum
10
Q
consists of muscles, which control and shape the lens
A
ciliary body
11
Q
the white of the eye
A
sclera
12
Q
Trace the path of visual information to the brain.
A
object - cornea - pupil - retina - optic nerve - optic chiasma - optic tract - thalamus - occipital lobe
13
Q
Information is divided into what 3 processing systems?
A
- shape
- color
- movement
14
Q
moves eye upward (oculomotor nerve)
A
superior rectus
15
Q
moves eye downward and outward (trochlear nerve)
A
superior oblique
16
Q
moves eye inward (oculomotor nerve)
A
medial rectus
17
Q
moves eye downward (oculomotor nerve)
A
inferior rectus
18
Q
moves eye upward and outward (oculomotor nerve)
A
inferior oblique
19
Q
moves eye outward (abducens nerve)
A
lateral rectus
20
Q
The membranes of neurons at rest are very permeable to ______ but only slightly permeable to ________
A
K+; Na+
21
Q
During depolarization, which gradient(s) move(s) Na+ into the cell?
A
both the electrical and chemical gradients
22
Q
What is the value for the resting membrane potential for most neurons?
A
-70mV
23
Q
The concentrations of which ions is highest outside the axon?
A
Na+ and Cl-
24
Q
What does the neuron use to move ions to compensate for Na+ and K+ leaks?
A
Na+/K+ pump
25
The Na+/K+ pump is a membrane _________ that uses _________ to move Na+ and K+ ions against their electrochemical gradients.
enzyme; active transport
26
To maintain the -70mV membrane potential the Na+/K+ pump continually moves _____ Na+ ions out of the neuron and _____ K+ ions into the neuron.
3;2
27
a transient change in the resting membrane potential from -70mV to +30mV, then back to -70mV
action potential
28
An action potential is caused by the opening of first _____ then ____ voltage-gated channels
Na+;K+
29
What area(s) of the neuron generate local signals that open the voltage-gated channels in the first part of the axon, thus causing an action potential to begin?
dendrites and cell body
30
As the axon hillock depolarizes, voltage gated Na+ channels open and Na+ moves __________ the cell causing further __________.
into; depolarization
31
If depolarization reaches -55mV, an action potential will be generated. What is this -55mV trigger point called?
threshold
32
The action potential is said to be a(n) ________ event
all or none
33
The voltage gated Na+ channels in the neuron have a voltage sensitive gate and a _____ sensitive gate
time
34
At the end of the depolarization phase, voltage gated _____ channels open to help restore the resting membrane potential.
K+
35
At what point in an action potential do the voltage gated K+ channels open? When are the fully activated?
middle of depolarization (0mV)
| once action potential has reached its peak
36
At rest the Na+ channels are ______ and the K+ channels are ________.
closed; closed
37
During depolarization, the Na+ channels are _______ and the K+ channels are ______ then _________
open; closed; open
38
During repolarization, the Na+ channels are ______ then _______ and the K+ channels are _____
inactive; closed; open
39
During hyperpolarization, the Na+ channels are _____ and the K+ channels are _______ then _______
closed; open; closed
40
When threshold is reached, the Na+ channels are ____ and the K+ channels are _______
open; closed
41
Depolarization is caused by the movement of which ion in what direction (in or out)?
sodium; into
42
Repolarization is caused by the movement of which ion in what direction (in or out)?
potassium; out
43
the period during which a neuron cannot generate another action potential, no matter how strong the stimulus
absolute refractory period
44
the period during which an action potential can be generated if depolarized to a point greater than threshold
relative refractory period
45
the speed with which an action potential is propagated
conduction velocity
46
Conduction velocity depends on what 2 factors?
1. diameter
| 2. myelination
47
the areas of bare axon on an otherwise myelinated axon
nodes of ranvier
48
an action potential jumping between the nodes of ranvier
saltitory conduction
49
reflexes that we are not aware of and cannot control; includes pupillary, ciliospinal, and salivary reflexes
autonomic reflexes
50
```
autonomic reflex:
retina ---> receptor
optic nerve ---> afferent fibers
oculomotor nerve ---> efferent impulses to eye
smooth muscle of iris ---> effector
```
pupillary reflex
51
reflexes that involve stimulation of skeletal muscle; includes stretch, crossed extensor, superficial cord, corneal, and gag reflexes
somatic reflexes
52
somatic reflex:
maintains posture, balance, and locomotion; hypoactive in PN damage or ventral horn disease; hyperactive in corticospinal tract lesions; ex. patellar reflex
stretch reflex
53
somatic reflex:
includes abdominal, cremaster, and plantar reflexes; results from pain and temperature changes; initiated by stimulation of receptors in skin and mucosae; depends on functional upper-motor pathways and cord-level reflex arc
superficial cord reflex
54
somatic reflex:
mediated through trigeminal nerve; absence indicates damage to brain stem resulting from compression of brain or other trauma
corneal reflex
55
in a reflex arc, the site of stimulus action
receptor
56
in a reflex arc, sends afferent impulses to the CNS
sensory neuron
57
in a reflex arc, one or more neurons in the CNS
integration center
58
in a reflex arc, sends efferent impulses from the integration center to the effector organ
motor neuron
59
in a reflex arc, responds to efferent impulses characteristically (muscle fibers or glands)
effector
60
response or reflex observed on the opposite side of the body than the side that was stimulated
contralateral response
61
any reflex occurring on the same side stimulated
ipsilateral response
62
react to stimuli or changes within the body and in the external environment
sensory receptors
63
react to touch, pressure, pain, heat, cold, stretch, vibration, and changes in position; distributed throughout the body
general senses
64
include sight, hearing, equilibrium, smell, and taste; small, localized group of receptors
special senses
65
react to stimuli in the external environment; typically found close to body surface; includes simple cutaneous receptors and special senses
exoreceptors
66
respond to stimuli within the body; found in internal visceral organs; includes stretch and chemoreceptors
interoceptors/visceroceptors
67
respond to internal stimuli but are restricted to skeletal muscles, tendons, joints, ligaments, and CT coverings of bone and muscle; provide information on position and degree of stretch
proprioreceptors
68
cutaneous receptors:
respond chiefly to pain and temperature; form merkel (tactile) discs and hair follicle receptors which function as light touch receptors
free (naked) nerve endings
69
cutaneous receptors:
| respond to light touch; located in dermal papillae of hairless skin only
meissner's (tactile) corpuscles
70
cutaneous receptors:
| respond to deep pressure and stretch stimuli
ruffini's corpuscles
71
cutaneous receptors:
| respond to deep pressure when first applied; best suited to monitor high-frequency vibrations
pacinian (lamellated) corpuscles
