PSL300 - CNS & Senses Questions With Complete Solutions
Accommodation Correct Answers - Rounding of lens in order
to increase refraction and focus on an object that is coming
closer
- Change in lens shape by contraction of cilliary muscles
- *Near point of accommodation*: closest point lens can focus
- An unconscious reflex
- Accommodation weakens as we age
Adequate stimulus Correct Answers A form of stimulus energy
that a receptor is most responsive to. (Although if there is
sufficient stimulus of another form, the receptors will often
respond as well.)
Angle of incidence Correct Answers - The angle at which
incoming light rays approaches a surface relative to a
perpendicular line from the surface
- Will affect the degree of refraction -- at some angles, light will
bend more, at others, light may not bend at all
- Changing shape of lens can alter the angle of incidence to
affect refraction
Anterior chamber Correct Answers Space in front of lens, filled
with *aqueous humour*, a plasma-like liquid.
Autonomic nervous systems Correct Answers In charge of
bodily functions of internal organs not consciously-controlled,
e.g. breathing & heart rate. Part of PNS.
Has several hundred million neurons.
,Axon tracts Correct Answers - Found in white matter of spinal
cord
- *Ascending tracts*: carry sensory signal to brain, mostly
dorsal (incoming sensory signals at dorsal horn)
- *Descending tracts*: carry signal from brain, mostly ventral
(where signals leave CNS)
- *Propriospinal tracts*: signals staying in spinal cord
Basal ganglia Correct Answers - Nuclei (clusters of neurons)
around centre of cerebrum
- Help control voluntary movement
Bipolar cells Correct Answers - Second layer of neurons on the
retina
- Synapse onto retinal ganglion cells and each is synapsed by
numerous photoreceptors
- Are not excited by photons
- 2 types:
1) *Light-on bipolar cells*: active in light
2) *Light-off bipolar cells*: active in darkness
Blind spot Correct Answers - Hole in retina where optic nerves
leave the eyeball
- Has no photoreceptors thus light hitting this spot on retina will
not be sensed
- No blind spots in regular vision because two eyes compensate
for blind spots in one another and brain fills in the blind spots
Brain Correct Answers 6 components:
1) Cerebrum
2) Cerebellum
3) Diencephalon
, 4) Midbrain
5) Pons
6) Medulla
Brain lobes Correct Answers 4 in each hemisphere:
1) Frontal
2) Temporal
3) Parietal
4) Occiptal
Brain stem Correct Answers - Medulla + pons + midbrain
- Feeds into cranial nerves III to XII
- Involved in autonomic functions (e.g. breathing, swallowing,
blood pressure regulation, vomiting)
Central nervous system Correct Answers - Brain + spinal cord
- Most neurons in body are in CNS (brain ≈ 86 bn, spinal cord ≈
1 bn)
- Filled with grey and white matter
Cerebral lateralization Correct Answers Left and right
hemispheres of cerebrum, although mostly quite similar, do have
unique functions.
Cerebrum Correct Answers - Largest part of the brain,
responsible for all voluntary activities of the body
- 2 hemispheres, connected by the corpus callosum
- Cortex (grey matter) + white matter + basal ganglia + corpus
callosum
Chemoreceptors Correct Answers - Receptors that respond to
ions and molecules
Accommodation Correct Answers - Rounding of lens in order
to increase refraction and focus on an object that is coming
closer
- Change in lens shape by contraction of cilliary muscles
- *Near point of accommodation*: closest point lens can focus
- An unconscious reflex
- Accommodation weakens as we age
Adequate stimulus Correct Answers A form of stimulus energy
that a receptor is most responsive to. (Although if there is
sufficient stimulus of another form, the receptors will often
respond as well.)
Angle of incidence Correct Answers - The angle at which
incoming light rays approaches a surface relative to a
perpendicular line from the surface
- Will affect the degree of refraction -- at some angles, light will
bend more, at others, light may not bend at all
- Changing shape of lens can alter the angle of incidence to
affect refraction
Anterior chamber Correct Answers Space in front of lens, filled
with *aqueous humour*, a plasma-like liquid.
Autonomic nervous systems Correct Answers In charge of
bodily functions of internal organs not consciously-controlled,
e.g. breathing & heart rate. Part of PNS.
Has several hundred million neurons.
,Axon tracts Correct Answers - Found in white matter of spinal
cord
- *Ascending tracts*: carry sensory signal to brain, mostly
dorsal (incoming sensory signals at dorsal horn)
- *Descending tracts*: carry signal from brain, mostly ventral
(where signals leave CNS)
- *Propriospinal tracts*: signals staying in spinal cord
Basal ganglia Correct Answers - Nuclei (clusters of neurons)
around centre of cerebrum
- Help control voluntary movement
Bipolar cells Correct Answers - Second layer of neurons on the
retina
- Synapse onto retinal ganglion cells and each is synapsed by
numerous photoreceptors
- Are not excited by photons
- 2 types:
1) *Light-on bipolar cells*: active in light
2) *Light-off bipolar cells*: active in darkness
Blind spot Correct Answers - Hole in retina where optic nerves
leave the eyeball
- Has no photoreceptors thus light hitting this spot on retina will
not be sensed
- No blind spots in regular vision because two eyes compensate
for blind spots in one another and brain fills in the blind spots
Brain Correct Answers 6 components:
1) Cerebrum
2) Cerebellum
3) Diencephalon
, 4) Midbrain
5) Pons
6) Medulla
Brain lobes Correct Answers 4 in each hemisphere:
1) Frontal
2) Temporal
3) Parietal
4) Occiptal
Brain stem Correct Answers - Medulla + pons + midbrain
- Feeds into cranial nerves III to XII
- Involved in autonomic functions (e.g. breathing, swallowing,
blood pressure regulation, vomiting)
Central nervous system Correct Answers - Brain + spinal cord
- Most neurons in body are in CNS (brain ≈ 86 bn, spinal cord ≈
1 bn)
- Filled with grey and white matter
Cerebral lateralization Correct Answers Left and right
hemispheres of cerebrum, although mostly quite similar, do have
unique functions.
Cerebrum Correct Answers - Largest part of the brain,
responsible for all voluntary activities of the body
- 2 hemispheres, connected by the corpus callosum
- Cortex (grey matter) + white matter + basal ganglia + corpus
callosum
Chemoreceptors Correct Answers - Receptors that respond to
ions and molecules
