Bio 207 Exam 2 Questions With Complete Solutions
Between cones and rods, which ones are responsible for visual
acuity and sensitivity and why? Correct Answers Cones
because they respond to colors and rods don't because they
function at only one wavelength. Cones also have their own
bipolar and ganglionic cells while rods have to share them.
Describe ion gating in axons Correct Answers Changes in
membrane potential are controlled by changes in the flow of
ions through ion channels.
K+ has two types of channels:
Not gated (always open); sometimes called "leaky" K+
channels
Voltage-gated K+ channels; open when a particular membrane
potential is reached
Na+ has only voltage-gated channels that are closed at rest.
The membrane is less permeable to Na+ at rest.
How are action potentials transmitted down an axon? Correct
Answers Na+ ions are conducted to an adjacent area where they
lower the membrane potential to its threshold and then trigger an
action potential. The original active area returns to its rest in
potential and the new active area triggers an action potential in
the adjacent inactive area.
How are the images of moving objects focused? Correct
Answers The contraction of the ciliary muscles allows the eyes
to focus on distant, close, and moving objects
,How do amphetamines work? Correct Answers Amphetamines
work by stimulating norepinephrine pathways in the brain
(associated with arousal).
How do left and right cerebral hemispheres communicate and
what are their functional specialties? Correct Answers They
communicate through the Corpus Callosum, which is a bridge
between the two hemispheres
Left Hemi - language, logic, math, controls right side, Broca's
area and Wernicke's area
Right Hemi - nonverbal (musical, perceptual, art, pictures)
pattern recognition, processes info holistically rather than
individually
How do you distinguish between spatial and temporal
summation? Correct Answers Spatial summation occurs due to
convergence of signals onto a single postsynaptic neuron.
Temporal summation is due to successive waves of
neurotransmitter released from the same neuron.
How do you distinguish sensory deafness from conductive
deafness and what factors can cause conductive deafness?
Correct Answers Conductive deafness - impaired transmission
of sound waves through the middle ear due to excessive fluid
accumulation or immobilization of the stapes due to
ostosclerosis (bone resorption and deposition). This impairment
covers all sound frequencies. Sensory deafness - caused by
nerve damage, usually attributed to exposure to very loud
sounds, may impair hearing of only certain frequencies
, How does acetylcholine (Ach) produce EPSP (Nicotinic Ach
receptors) and IPSP (Muscuranic Ach receptors)? Correct
Answers For EPSP, ACh binds to the nicotine receptor and then
lets in Na+ while K+ escapes. This produces a small EPSP
which may produce a threshold potential leading to an action
potential. For IPSP, the ACh receptor is linked to a K+ channel
through G-protein intermediates. When ACh binds to this
receptor a change in the conformation (shape) of the receptor
occurs, which activates G-protein operated K+ channel. K+
leaves the cell and leads to an IPSP.
How is Acetylcholine (ACh) action terminated? Correct
Answers It is removed by acetylcholinesterase (AChE), which
is located on cleft in post-synaptic membrane.
How is color vision perceived? Correct Answers Trichromatic
Theory: There are three different types of cones, red, green and
blue
How is glaucoma caused? Correct Answers Glaucoma is caused
by the inadequate drainage of aqueous humor, which normally
provides nourishment to the lens and cornea
In Parkinson's and Alzheimer diseases which neurotransmitters
are affected? Correct Answers Parkinson's disease is caused by
the degeneration of motor neurons. Alzheimer's is associated
with loss of cholinergic neurons that synapse on the areas of the
brain responsible for memory.
Between cones and rods, which ones are responsible for visual
acuity and sensitivity and why? Correct Answers Cones
because they respond to colors and rods don't because they
function at only one wavelength. Cones also have their own
bipolar and ganglionic cells while rods have to share them.
Describe ion gating in axons Correct Answers Changes in
membrane potential are controlled by changes in the flow of
ions through ion channels.
K+ has two types of channels:
Not gated (always open); sometimes called "leaky" K+
channels
Voltage-gated K+ channels; open when a particular membrane
potential is reached
Na+ has only voltage-gated channels that are closed at rest.
The membrane is less permeable to Na+ at rest.
How are action potentials transmitted down an axon? Correct
Answers Na+ ions are conducted to an adjacent area where they
lower the membrane potential to its threshold and then trigger an
action potential. The original active area returns to its rest in
potential and the new active area triggers an action potential in
the adjacent inactive area.
How are the images of moving objects focused? Correct
Answers The contraction of the ciliary muscles allows the eyes
to focus on distant, close, and moving objects
,How do amphetamines work? Correct Answers Amphetamines
work by stimulating norepinephrine pathways in the brain
(associated with arousal).
How do left and right cerebral hemispheres communicate and
what are their functional specialties? Correct Answers They
communicate through the Corpus Callosum, which is a bridge
between the two hemispheres
Left Hemi - language, logic, math, controls right side, Broca's
area and Wernicke's area
Right Hemi - nonverbal (musical, perceptual, art, pictures)
pattern recognition, processes info holistically rather than
individually
How do you distinguish between spatial and temporal
summation? Correct Answers Spatial summation occurs due to
convergence of signals onto a single postsynaptic neuron.
Temporal summation is due to successive waves of
neurotransmitter released from the same neuron.
How do you distinguish sensory deafness from conductive
deafness and what factors can cause conductive deafness?
Correct Answers Conductive deafness - impaired transmission
of sound waves through the middle ear due to excessive fluid
accumulation or immobilization of the stapes due to
ostosclerosis (bone resorption and deposition). This impairment
covers all sound frequencies. Sensory deafness - caused by
nerve damage, usually attributed to exposure to very loud
sounds, may impair hearing of only certain frequencies
, How does acetylcholine (Ach) produce EPSP (Nicotinic Ach
receptors) and IPSP (Muscuranic Ach receptors)? Correct
Answers For EPSP, ACh binds to the nicotine receptor and then
lets in Na+ while K+ escapes. This produces a small EPSP
which may produce a threshold potential leading to an action
potential. For IPSP, the ACh receptor is linked to a K+ channel
through G-protein intermediates. When ACh binds to this
receptor a change in the conformation (shape) of the receptor
occurs, which activates G-protein operated K+ channel. K+
leaves the cell and leads to an IPSP.
How is Acetylcholine (ACh) action terminated? Correct
Answers It is removed by acetylcholinesterase (AChE), which
is located on cleft in post-synaptic membrane.
How is color vision perceived? Correct Answers Trichromatic
Theory: There are three different types of cones, red, green and
blue
How is glaucoma caused? Correct Answers Glaucoma is caused
by the inadequate drainage of aqueous humor, which normally
provides nourishment to the lens and cornea
In Parkinson's and Alzheimer diseases which neurotransmitters
are affected? Correct Answers Parkinson's disease is caused by
the degeneration of motor neurons. Alzheimer's is associated
with loss of cholinergic neurons that synapse on the areas of the
brain responsible for memory.
