Neuroscience: Central Nervous System Tracts

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Questions and Answers

Which nerve from the sacral plexus is primarily responsible for supplying the foot?

Tibial nerve (correct)

Femoral nerve

Radial nerve

Fibular nerve

What characterizes visceral reflexes compared to somatic reflexes?

Require higher brain functions for execution

Control skeletal muscles only

Involve voluntary muscle activation

Control smooth and cardiac muscles, and glands (correct)

What is a common cause of sciatic nerve injury?

Trauma from sports injuries

Herniated intervertebral disc or osteoarthritis (correct)

Chemical exposure

Excessive exercise

Which type of reflex involves the highest complexity and speed?

Polysynaptic reflexes Signup and view all the answers

Which component of the muscle spindle is responsible for adjusting the sensitivity of the spindle?

Gamma motor neuron Signup and view all the answers

The term 'wrist drop' is associated with injury to which nerve?

Radial nerve Signup and view all the answers

Which statement correctly describes the characteristics of muscle cells?

All muscle cells have contractility and elasticity. Signup and view all the answers

What describes the stretch (myotatic) reflex?

Causes contraction when a muscle is stretched to maintain balance Signup and view all the answers

Which nerve supplies the medial and anterior compartments of the leg?

Femoral nerve Signup and view all the answers

What is a primary function of beta-3 adrenergic receptors?

Lipolysis in adipocytes. Signup and view all the answers

Which of the following is NOT a function of skeletal muscle tissue?

Support the vascular system. Signup and view all the answers

Which neurotransmitter is released by the autonomic nervous system alongside acetylcholine and norepinephrine?

Substance P. Signup and view all the answers

What role do the arrector muscles play in the autonomic nervous system?

They are affected only by sympathetic fibers. Signup and view all the answers

What is a characteristic feature of muscle spindles?

They contain sensory endings that respond to stretch. Signup and view all the answers

Which is a common outcome of decreased blood flow as controlled by the autonomic nervous system?

Decreased glandular secretion. Signup and view all the answers

What is a key characteristic of polysynaptic reflexes?

They require multiple interneurons to connect sensory and motor pathways. Signup and view all the answers

What is the primary motor function of the Accessory Nerves (XI)?

Neck and upper back movement Signup and view all the answers

Which of the following nervous functions is NOT associated with the Glossopharyngeal Nerves (IX)?

Facial expression control Signup and view all the answers

What role does the coccygeal ligament play in the spinal cord?

Anchors the spinal cord to prevent longitudinal movement Signup and view all the answers

Which structure is primarily responsible for detecting changes in muscle length?

Muscle spindles Signup and view all the answers

In the context of spinal reflexes, which characteristic defines a polysynaptic reflex?

Allows for multiple routes of neural communication Signup and view all the answers

Which of the following components is NOT a part of the gray matter in the spinal cord?

Myelinated axons Signup and view all the answers

During the epidural block procedure, which type of anesthesia is administered?

Epidural anesthesia Signup and view all the answers

From which region does the lumbosacral enlargement provide nerves?

Pelvic region and lower limbs Signup and view all the answers

Study Notes

Tracts in the Central Nervous System (CNS)

Tracts are bundles of nerve fibers in the CNS.
Three types: projection, commissural, and association tracts.
Projection tracts extend vertically between the cerebrum and lower brain/spinal cord centers.
Commissural tracts cross from one cerebral hemisphere to the other, allowing communication between the two sides of the cerebrum. Most pass through the corpus callosum.
Association tracts connect different regions within the same cerebral hemisphere. Long association fibers connect different lobes, while short association fibers connect gyri within a lobe.

Disconnection Syndrome

Cutting the corpus callosum (to treat severe epilepsy) can cause a disconnection syndrome.
Each hemisphere becomes aware of the other, but the hemispheres are disconnected from each other.
For example, an item held in the left hand might not be able to be verbally identified.

Language Areas in the Brain

Posterior speech area (Wernicke area): Usually in the left hemisphere, responsible for recognizing spoken and written language. Located posterior to the lateral sulcus.
Motor language area (Broca area): Usually in the left hemisphere, controls the muscles of the larynx, tongue, cheeks, and lips for speaking and hand movements for signing. Located in the inferior prefrontal cortex.
Aphasia is a disorder of language. It can be caused by lesions of the Wernicke or Broca areas.
- Nonfluent aphasia: approximated words, difficulty with specific word formation, but can produce similar sounding substitutes.
- Fluent aphasia: words are made up , nonsensical, or gibberish

Hemisphere Differences

Left hemisphere is usually the categorical hemisphere and is specialized for spoken and written language, in 96% of right-handed people and 70% of left-handed people.

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Description

Explore the types of tracts in the central nervous system, including projection, commissural, and association tracts. Learn about the implications of cutting the corpus callosum and how it leads to disconnection syndrome. Additionally, understand the role of language areas in the brain.