Questions and Answers
What is the general purpose of the sympathetic nervous system?
Its primary purpose is to stimulate the body's fight-flight-or-freeze response and maintain homeostasis.
Where are sympathetic preganglionic cell bodies located?
In the spine.
Where are sympathetic postganglionic cell bodies located?
In a sympathetic ganglion, next to the spinal cord.
How does the sympathetic nervous system affect the cardiovascular and respiratory systems?
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How does the sympathetic nervous system affect the digestive system?
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What is the general purpose of the parasympathetic nervous system?
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Where are parasympathetic preganglionic cell bodies located?
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Where are parasympathetic postganglionic cell bodies located?
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How does the parasympathetic nervous system affect the cardiovascular and respiratory systems?
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How does the parasympathetic nervous system affect the digestive system?
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Describe how light activates photoreceptors.
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Explain how the optical system of the eye creates an image on the retina.
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What are the functions of rods?
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What are the functions of cones?
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Trace the path of light as it passes through the eye to the retina.
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Explain the process of light adaptation.
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Study Notes
Sympathetic Nervous System
- Stimulates the body's fight-flight-or-freeze response; constantly active to maintain homeostasis
- Preganglionic cell bodies located in the spine
- Postganglionic cell bodies found in sympathetic ganglia next to the spinal cord
- Affects cardiovascular and respiratory systems: increases heart rate, dilates bronchial passages, constricts blood vessels, enhances peristalsis, and raises blood pressure
- Inhibits gastrointestinal secretion and motor activity; causes contraction of sphincters and blood vessels
Parasympathetic Nervous System
- Conserves energy; slows heart rate and increases intestinal and gland activity
- Preganglionic cell bodies found in brain stem or sacral spinal cord
- Postganglionic cell bodies located in ganglia near target organs
- Affects cardiovascular and respiratory systems by slowing both heart and respiratory rates
- Increases intestinal and gland activity, relaxing sphincter muscles
Photoreceptors and Vision
- Light activates photoreceptors by absorbing photons, which changes the cell's membrane potential
- Rods and cones release neurotransmitters when depolarized in the dark; hyperpolarizes bipolar cells, preventing signal transmission to ganglion cells
- Image formation on the retina occurs as light rays converge at the cornea and lens, creating an inverted image
Functions of Rods and Cones
- Rods function in low light; do not process color and have low spatial acuity
- Cones function in bright light; enable color vision (blue, green, red) and high spatial acuity
Visual Processing Pathway
- Light travels through the cornea and lens to focus on the retina
- Retina converts light to electrochemical impulses sent via the optic nerve to the brain
- Output from retina passes through optic chiasm, optic tract to LGN, and then to the primary visual cortex
Light Adaptation Process
- In low light, rods regenerate rhodopsin quickly, maintaining sensitivity to light
- In high light, rhodopsin is rapidly bleached, making some rods nonfunctional; cones then take over
- Automatic adjustment of retinal sensitivity occurs according to light intensity
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Description
Explore the key functions and components of the sympathetic and parasympathetic nervous systems. This quiz covers their roles in maintaining homeostasis, effects on the cardiovascular and respiratory systems, and energy conservation. Test your knowledge on how these systems interact and influence the body's response.