SCB 203 - Lecture Quiz 3A

Lectures 10-15

True or false: Autonomic motor neurons do not directly innervate target cells.

True

Which neurons are involved in an autonomic motor pathway?

A preganglionic and postganglionic neuron

True or false: The two neurons of the autonomic nervous system synapse in the autonomic ganglion in the PNS.

True

Which neurotransmitters are released by the autonomic nervous system?

Acetylcholine (ACh) and norepinephrine (NE)

True or false: The autonomic nervous system controls vital functions such as heart rate, blood pressure, and digestive and urinary processes.

True

True or false: The autonomic nervous system operates without conscious control.

True

Which does the autonomic nervous system function through?

Visceral reflex arcs

Which regions of the spinal cord do preganglionic neurons of the sympathetic nervous system originate in?

Thoracic and lumbar spinal cord (Thoracolumbar division)

Which is the name for the location of sympathetic postganglionic cell bodies?

Sympathetic chain ganglia

Which is the location of sympathetic chain ganglia?

Near the spinal cord along the vertebral column

Which regions of the spinal cord do preganglionic neurons of the parasympathetic nervous system originate in?

Cranial nerves of the brainstem and sacral spinal cord (Craniosacral division)

Which is the location of postganglionic neurons of the parasympathetic nervous system?

Ganglia near or within the target organs

Which neurotransmitter do both divisions of the autonomic nervous system release from preganglionic axons?

Acetylcholine (ACh)

Which receptor does ACh bind to on postganglionic neurons?

Nicotinic receptors

Which neurotransmitter do parasympathetic postganglionic neurons release?

Acetylcholine (ACh)

Which receptors does parasympathetic postganglionic ACh bind to on target cells?

Muscarinic receptors

Which neurotransmitters do most sympathetic postganglionic neurons release?

Norepinephrine (NE) or epinephrine (E) (adrenergic fibers)

Which receptors do NE and E bind to on sympathetic target cells?

Adrenergic receptors

True or false: Some sympathetic postganglionic neurons release ACh, which binds to muscarinic receptors (cholinergic fibers)​.

True

Which cranial nerves are associated with the parasympathetic nervous system?

Oculomotor (III), Facial (VII), Glossopharyngeal (IX), and Vagus (X)

Which sacral nerves are associated with the parasympathetic nervous system?

S2–S4 which form the pelvic splanchnic nerves

Parasympathetic branches form plexuses in and synapse in:

Terminal ganglia near target organs

Which is an autoimmune disorder that attacks the myelin sheath around CNS axons?

Multiple Sclerosis

Which is a disorder associated with the degeneration of α-motor neuron cell bodies in the anterior horn of the spinal cord and upper motor neurons of the cerebral cortex​?

Lou Gehrig’s Disease (ALS)

Which is the correct order of the process of sensation?

1. Stimulus is detected by sensory receptors of the PNS

2. The signal is transmitted by PNS sensory neurons to the CNS

3. The signal is integrated and interpreted by CNS neurons​

Which are general senses?

Touch, temperature, and pain

Which detects the general senses?

Receptive endings of sensory neurons

Which transmits the general senses?

Spinal and cranial nerves

Which are special senses?

Light, sound, head movement, smell, and taste

Which detects the special senses?

Specialized cells, except for in olfaction

Which transmits the special senses?

Cranial nerves

True or false: All senses are detected by specialized cells.

False, olfaction receptors are neurons

Which refers to the conversion of a stimulus into electrical signals?

Sensory transduction

Which is the correct order of the events of sensory transduction?

1. Ion channels are closed at rest

2. Mechanically gated Na⁺ channels open, causing receptor potential

3. If the threshold is reached, voltage-gated Na⁺ channels open, triggering an action potential​.

True or false: Ion channels of sensory receptors are closed at rest.

True

Which type of ion channels open during transduction to cause receptor potential?

Mechanically gated Na⁺ channels

Which triggers the action potential in sensory transduction?

Opening of voltage-gated Na⁺ channels

Which location of stimuli do exteroceptors detect?

External stimuli like light, texture, and temperature

Which location of stimuli do interoceptors detect?

Internal stimuli like blood pressure and organ stretch

Which type of stimuli do mechanoreceptors detect?

Physical deformation

Which type of stimuli do thermoreceptors detect?

Thermal stimuli

Which type of stimuli do chemoreceptors detect?

Chemical stimuli

Which type of stimuli do photoreceptors detect?

Light stimuli

Which type of stimuli do nociceptors detect?

Pain

Which type of adapting receptors respond quickly but stop signaling during continuous stimulation?

Rapidly adapting receptors

Which is an example of a rapidly adapting receptor?

Lamellated (Pacinian) corpuscles

Which type of adapting receptors maintain signaling during continuous stimulus?

Slowly adapting receptors

Which is an example of a slowly adapting receptor?

Ruffini endings

Which describes when light rays from distant objects are nearly parallel and focus on the retina with minimal lens refraction?

Emmetropic state

Which describes when the lens rounds up to increase refraction for focusing on nearby objects?

Accommodation

Which structure performs most of the eye’s refraction?

Cornea

Which structure adds more refraction in focusing light, especially during accommodation?

Lens

Which describes how the shape of the lens changes during distant vision?

The ciliary body relaxes and suspensory ligaments tighten to flatten the lens

Which describes how the shape of the lens changes during near vision?

The ciliary body contracts and suspensory ligaments loosen to round the lens

Which condition is caused by stiffening of the lens, reducing accommodation, with age?

Presbyopia

Which condition is caused by an eyeball that is too short or a cornea that is too flat?

Hyperopia (farsightedness)

Which is the location of the image focused in hyperopia (farsightedness)?

Behind the retina

Which type of lens corrects hyperopia?

Convex

Which condition is caused by an eyeball that is too long or a cornea that is too curved?

Myopia (nearsightedness)

Which is the location of the image focused in myopia (nearsightedness)?

In front of the retina

Which type of lens corrects myopia (nearsightedness)?

Concave

Which condition is caused by irregular curvature of the cornea or lens, leading to uneven refraction?

Astigmatism

Which are the CNS regions associated with the special sense vision?

Information travels to the primary visual cortex via the optic nerve

Which are the CNS regions associated with the special sense hearing in the auditory pathway?

Cochlear nerve → Vestibulocochlear nerve → Cochlear nucleus (medulla-pons junction) → Superior olivary nucleus (pons) → Inferior colliculus (midbrain) → Medial geniculate nucleus (thalamus) → Primary auditory cortex (temporal lobe)​

Which are the CNS regions associated with the special sense equilibrium in vestibular sensation?

Travels through the vestibulocochlear nerve and targets vestibular nuclei in the brainstem, thalamus, cerebellum, spinal cord, and oculomotor control nuclei​

Which are the CNS regions associated with the special sense olfaction?

Olfactory bulb → Primary olfactory cortex (temporal lobe)

True or false: The olfactory pathway synapses in the thalamus.

False

Which are the additional CNS regions associated with the integration of the special senses olfaction and gustation?

Amygdala, Hippocampus, Hypothalamus, and Frontal lobe

Which are the CNS regions associated with the special sense gustation?

Signals are carried via the Facial nerve (VII), Glossopharyngeal nerve (IX), and Vagus nerve (X) to brainstem nuclei

Which are the layers of the retina?

Outer pigmented epithelium and inner neural layer

Which types of cells are found in the inner neural layer of the retina?

Photoreceptors and neurons

Which are the cylindrical outer segments of photoreceptors?

Rods

Which are the conical outer segments of photoreceptors?

Cones

Which pigment do rods contain?

Rhodopsin (opsin + retinal)

Which pigment do cones contain?

Iodopsin (photopsin + retinal)

Which photoreceptor functions best in dim light?

Rods

Which photoreceptor functions best in bright light and color vision?

Cones

Which photoreceptor is highly concentrated in the fovea centralis​ of the retina?

Cones

Which state is rhodopsin in in darkness?

Intact as opsin + cis-retinal

Which is the correct order of transduction of photoreceptors in the dark?

cGMP keeps Na⁺ channels open → depolarization → continuous neurotransmitter release

Which molecule keeps Na⁺ channels open in dark-adapted photoreceptors?

cGMP

Which is the result of Na⁺ channels being open in the dark?

Depolarization and continuous neurotransmitter release

Which is the correct order of transduction of photoreceptors in the light?

Retinal changes to trans-retinal → rhodopsin bleaches → activates transducin → activates PDE → cGMP → GMP → Na⁺ channels close → hyperpolarization → neurotransmitter release reduced

Which happens to retinal in light?

It converts to trans-retinal

Which happens when rhodopsin is bleached by light?

It activates transducin

Which is activated by transducin?

Phosphodiesterase (PDE)

Which describes the role of PDE in phototransduction?

Converts cGMP to GMP

Which happens when cGMP levels fall?

Na⁺ channels close

Which is caused by the closing of Na⁺ channels?

Hyperpolarization and reduced neurotransmitter release

Which describes transduction in photoreceptors as they adapt to darkness?

Rods regenerate rhodopsin slowly, taking up to 40 minutes

Which describes transduction in photoreceptors as they adapt to light?

Rods are quickly bleached and cones adapt within minutes

Which describes how photoreceptors synapse for image processing in the retina?

Synapses with bipolar cells → retinal ganglion cells

Which describes how the fovea centralis synapses for image processing in the retina?

Synapses with each cone → 2 bipolar cells → 1 ganglion cell → sharp vision

Which cells modulate signals between photoreceptors and bipolar cells?

Horizontal cells

Which cells modulate signals along the dendrites of ganglion cells​?

Amacrine cells

Which cells do photoreceptors synapse with?

Bipolar cells

Which cells do bipolar cells synapse with?

Retinal ganglion cells

Which describes how cones connect to bipolar and ganglion cells in the fovea centralis?

Each cone connects to 2 bipolar cells and 1 ganglion cell

Which regions of the central nervous system does visual stimuli travel to? 

Sent from photoreceptors of the retina through the optic nerve and to the brain for conscious awareness and interpretation

Which is the correct order of the transmission of sound in the inner ear?

Sound waves are funneled into the auditory canal → strike the tympanic membrane → ossicles → oval window → generate waves in the perilymph of the scala vestibuli and endolymph of the cochlear duct → basilar membrane vibrates for hearing​