BPK 105 Chapter Notes - Chapter 4-6: Sympathetic Nervous System, Glycogen, Thyroid
2 Jul 2018
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Module 4:
8. Define reflex. Draw a diagram of a reflex arc that would result in muscle contraction following
the stimulation of a pain receptor in the skin. What type of reflex is this? Label the five
components of the reflex arc in your diagram and the components of the spinal cord. [8 marks]
10. Describe the roles of the cerebellum and basal nuclei in the control and modification of
movement. [5 marks]
The basal nuclei and cerebellum both take part in motor functions. The basal nuclei is
made up of a group of functionally related nuclei. The corpus striatum (found deep within the
cerebrum and substantia nigra (darkly pigmented cells in the midbrain) are the two primary
nuclei. The basal nuclei play a key role in planning, organizing, as well as coordinating motor
movements and posture. The basal nuclei are linked by complex neural circuits alone with the
thalamus and cerebral cortex that together create feedback loops such as stimulatory (promote
muscle activity) and inhibitory circuits (inhibit muscle activity in antagonist muscles to promote
the process of stimulatory circuits). The cerebellum is responsible for keeping balance and
muscle tone as well as organizing fine motor movement. (VanPutte pg 21-219).
Module 5:
4. What is the role of mucus in the detection of smell? Describe the pathway from odorant
molecule binding to a receptor to the olfactory bulb. What happens after you have been
exposed to an odorant for a long time? [5 marks]
Mucus found on the surface of the epithelium is where airborne odorants dissolved into
and bind to receptor molecules. This binding initiates an action potential which are sent by
sensory neurons to the olfactory cortex in the cerebrum. The olfactory neurons contain
axons which form the olfactory nerves which go through the formamina of the cribriform
plate and enter the olfactory bulb where they synapse with interneurons that transfer action
potentials to the olfactory tracts to the brain. Prolong exposure to an odor causes feedback
loops in the olfactory bulb and olfactory cortex to inhibit action potentials being sent which
causes an adaptation to a given odor by decreasing sensitivity at the receptors. (VanPutte
pg. 243-244).
7 Describe the effect of light on rhodopsin. How is light changed into an electrical signal?
(please see the study guide in Canvas for more detail) [4 marks]
Rhodopsin is a photosensitive pigment found in rod cells that contains a colourless
protein called opsin that combined chemically with retinal, a yellow pigment. When light
strikes the rod it causes the retinal to change shape, which causes the opsin to change
shape. The opsin molecule separates from the retinal and causes the rhodopsin to activate
and the membrane to change its permeability to sodium ion and alter the membrane
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Document Summary
Draw a diagram of a reflex arc that would result in muscle contraction following the stimulation of a pain receptor in the skin. Label the five components of the reflex arc in your diagram and the components of the spinal cord. [8 marks: describe the roles of the cerebellum and basal nuclei in the control and modification of movement. The basal nuclei and cerebellum both take part in motor functions. The basal nuclei is made up of a group of functionally related nuclei. The corpus striatum (found deep within the cerebrum and substantia nigra (darkly pigmented cells in the midbrain) are the two primary nuclei. The basal nuclei play a key role in planning, organizing, as well as coordinating motor movements and posture. The cerebellum is responsible for keeping balance and muscle tone as well as organizing fine motor movement. (vanputte pg 21-219). Describe the pathway from odorant molecule binding to a receptor to the olfactory bulb.
