Anatomy Lecture Final Term 2 (quizzes)

Terms in this set (81)

Wernicke's area
Correct! The Wernicke's area is a region of the cerebral cortex encompassing parts of the parietal, occipital and temporal lobes. When language is spoken, the sounds travel to the primary auditory cortex in the temporal lobe and then are relayed to the auditory association areas; in the association areas the sounds are identified as language (instead of music). When written words are read, the visual information is sent to the primary visual cortex in the occipital lobe and then relayed to the nearby association area; here, the visual information is interpreted as the shapes that make words. From these regions of the brain, information is then sent to the Wernicke's area. When the information is relayed to the Wernicke's area, you become fully able to comprehend that which you saw or heard. If a response is required, you will form the response here, but to speak it, you need to send information to the Broca's area.
The Broca's area is the motor speech association area of the premotor cortex (frontal lobe, just anterior to the precentral gyrus). To speak, the motor signals are formulated here and then sent to the appropriate neurons of the precentral gyrus; the neurons in the precentral gyrus control your tongue, pharyngeal muscles and respiratory muscles to form words. In short, Broca's is the motor planning area for speech, not the interpretive area*.
The thalamus is important as a relay station for sensory and motor information.
The prefrontal cortex influences your appreciation of consequences, personality, reasoning and judgement. Although these may seem like qualities for appropriate conversation, damage to them will not influence your ability to understand spoken or written language.*

*In some cases, when words or text are very complex and ambiguous, the Broca's area and other regions of the frontal lobe can become engaged to comprehend the language. This is the amazing concept about the brain, many overlapping functions and an exception to every rule! This question with the given options is not a great test question.
Decreased muscle force production of the right upper limb

Right! The brachial plexus contains neurons that innervate the upper limb. In a brachial plexus, multiple spinal nerves mix and mingle so that axons from each spinal nerve find their way into many different nerves. These "new" nerves then serve structures in the upper limb (either muscles or regions of skin).

In this question, the ventral root of C6 is damaged. The ventral root contains motor neurons that innervate skeletal muscle. If these motor neurons are damaged, the muscle cells served by the axons emerging from C6 will not be able to contract and contribute to force production. However, because each whole muscle is served by many axons from many different spinal nerves, the whole muscle (and limb) will still have neural activation and be able to produce some force, although less muscle cells can be activated and thus less overall force production.
There will not be loss of sensation because the ventral root is damaged which only contains motor neurons. The sensory neurons travel in the dorsal root and are still able to conduct sensory information.
Breathing is a combined function of the diaphragm and rib movement. The diaphragm is innervated by the phrenic nerve from the cervical plexus. The ribs are served by nerves from thoracic spinal nerves. C6 does not contribute to the phrenic nerve. Even if it did, the phrenic nerve has axons from multiple spinal nerves and will still be able to function should one spinal root be damaged.
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Correct! You inherently know this - think of a very bad odor, like rotting food or cigarette smoke. You can detect these odors although very little of them many be present. It is similar for the chemical they put in natural gas that is piped into your home. These odorants trigger the olfactory receptors to generate action potentials when just a few molecules are present (although with natural gas, 1 in 1000 people cannot detect that odor). Sometimes we can adapt to these noxious fumes - like smokers who gradually destroy their olfactory receptors with the toxins in cigarette smoke (not true adaptation, but the same effect), or decreased production of the receptors on the receptor cells for that odorant/tastant or our brain activates GABA secreting neurons in the olfactory pathway to inhibit signal transmission - but for others, we cannot adapt.

Other odorants/tastants require more of the molecules to be present to initiate an effect in the receptor cells. Because these modalities are mediated by a chemically gated channel, you can think of the odorant/tastant like we think of neurotransmitters on a postsynaptic cell. Bigger graded potentials are generated when there are more receptors for the neurotransmitter or the neurotransmitter is present for longer. Odorants/tastants that bind for long periods or find more receptors can have a big effect despite have few molecules present. The other factors that affect an odorant's ability to trigger awareness is the odorant's ability to dissolve in your nasal mucosa and find the olfactory receptor cells. If you have a very dry nose or an overly mucous filled nose (stuff nose), odorants cannot reach the receptors.
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