Central Nervous System Overview

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Questions and Answers

Which hemisphere is typically dominant for language functions?

Both hemispheres equally

Neither hemisphere

Left hemisphere (correct)

Right hemisphere

What condition may arise from damage to the posterior association area?

Memory loss for recent events

Contralateral neglect (correct)

Impaired language comprehension

Difficulty in emotional regulation

Wernicke's area is primarily involved in which of the following?

Emotional responses

Motor control

Understanding written and spoken language (correct)

Visual-spatial skills

How does the anterior association area contribute to personality?

It influences judgment, reasoning, and social behavior. Signup and view all the answers

What is cerebral dominance typically associated with in terms of handedness?

Left hemisphere dominance in most right-handed individuals Signup and view all the answers

Phineas Gage is a historically significant case because it showed a link between brain injury and which of the following?

Significant personality changes Signup and view all the answers

What role does the limbic association area play in emotional responses?

It assigns emotional significance based on experience. Signup and view all the answers

In terms of neural communication, how do the two hemispheres of the brain interact?

They utilize the corpus callosum for interaction. Signup and view all the answers

What is the primary function of the premotor cortex?

To coordinate complex motor tasks Signup and view all the answers

What characteristic is unique to Broca's area?

It is involved in preparing for speech Signup and view all the answers

What does the primary somatosensory cortex (PSC) primarily process?

Somatic sensory information Signup and view all the answers

What happens when there is damage to the area of the premotor cortex responsible for keyboarding?

Difficulty planning and sequencing finger movements Signup and view all the answers

In which hemisphere of the brain is Broca's area typically located?

Left hemisphere Signup and view all the answers

Which area of the brain integrates and analyzes somatic sensory inputs?

Somatosensory association cortex Signup and view all the answers

What does the frontal eye field control?

Voluntary eye movements Signup and view all the answers

Why is the term 'muscle memory' considered misleading?

Muscles do not have the capacity for memory. Signup and view all the answers

What primarily distinguishes gray matter from white matter in the nervous system?

Gray matter consists mainly of cell bodies and unmyelinated neurons, while white matter is composed of myelinated axons. Signup and view all the answers

Which of the following correctly describes the function of the sympathetic division of the autonomic nervous system?

Facilitates 'fight or flight' responses. Signup and view all the answers

Which structures are part of the diencephalon?

Thalamus, hypothalamus, and epithalamus. Signup and view all the answers

What is the primary function of the cerebral ventricles?

They produce cerebrospinal fluid (CSF) and connect to the central canal of the spinal cord. Signup and view all the answers

What is the role of ependymal cells in relation to the brain's ventricles?

They produce and line the cerebrospinal fluid (CSF). Signup and view all the answers

Which division of the peripheral nervous system is responsible for carrying motor signals from the CNS to skeletal muscles?

Somatic nervous system. Signup and view all the answers

Which structure in the brain plays a key role in language processing?

Wernicke's area. Signup and view all the answers

The basal nuclei are associated with which of the following functions?

Control of voluntary movement. Signup and view all the answers

Study Notes

Central Nervous System (CNS)

The nervous system is a single unit, anatomically divided into two parts:
- Central Nervous System (CNS):
  - Consists of the brain and spinal cord
  - Acts as the integrating and command center
- Peripheral Nervous System (PNS):
  - Includes cranial and spinal nerves
  - Facilitates communication between the CNS and the body

Sensory and Motor Divisions

Sensory division:
- Somatic and visceral fibers carry signals from receptors to the CNS.
Motor division:
- Motor nerve fibers carry signals from the CNS to effectors.
- Somatic nervous system: controls voluntary movements, targeting skeletal muscles.
- Autonomic nervous system: regulates involuntary functions, affecting cardiac muscle, smooth muscle, and glands.
  - Sympathetic division: "fight or flight" response
  - Parasympathetic division: conserves energy during rest

Brain Structure

Complexity of wiring is more important than size
Subdivisions:
- Cerebral hemispheres
- Diencephalon (thalamus, hypothalamus, epithalamus)
- Brain stem (midbrain, pons, medulla)
- Cerebellum

Gray and White Matter

Gray matter:
- Consists of short, nonmyelinated neurons and neuron cell bodies
- Some gray matter is organized into nuclei
- Some is distributed as cortical areas
White matter:
- Primarily myelinated axons
- Some nonmyelinated axons may also be present

Spinal Cord Structure

Central cavity surrounded by gray matter (butterfly shape).
White matter surrounds the gray matter.
Brain displays similar design, but with additional gray matter regions, particularly in the cerebral hemispheres and cerebellum.

Ventricles of the Brain

Continuous with each other and the central cavity of the spinal cord.
Filled with cerebrospinal fluid (CSF).
Lined with ependymal cells.
Paired lateral ventricles are separated by the septum pellucidum.
Each communicates with a narrow third ventricle.
The third ventricle connects to the fourth ventricle via the cerebral aqueduct.
The fourth ventricle continues with the central canal.
Three apertures connect the ventricles to the subarachnoid space, which surrounds the brain.

Cerebral Hemispheres

Superior part (~83% of brain mass)
Gyri are separated by sulci.
Anatomical landmarks include the longitudinal fissure and a transverse fissure
Lobes (frontal, parietal, occipital, temporal, insular)
- Central sulcus separates precentral/postcentral gyrus.
- Other important sulci include the parieto-occipital and lateral sulci.

Cerebral Cortex (Gray Matter)

Enables perception, communication, memory, understanding, appreciation, and voluntary movements (conscious behavior)
Cell bodies, dendrites, and unmyelinated axons comprise a thin layer (2-4 mm), although convolutions increase the surface area.
Brodmann areas (BA) are numbered based on thickness and histology.
Functional areas include motor, sensory, and association areas.
Each hemisphere handles sensory and motor functions of the opposite (contralateral) side of the body.

Functional Areas

Motor areas:
- Primary motor cortex (BA4): precentral gyrus: controls skeletal muscles (axons project to spinal cord)
- Premotor cortex (BA6): plans and sequences motor movements, sometimes referred to as muscle memory.
- Broca's area (BA44): organizes the sounds that become words.
Frontal eye field (close to BA 8): controls voluntary eye movements.
Sensory areas:
- Primary somatosensory cortex (PSC) (BA1-3) in the postcentral gyrus: receives info from somatic sensory receptors (skin and proprioceptors).
- Includes spatial discrimination.
- Somatosensory association cortex (BA 5-7): integrates sensory input.
Visual areas:
- Primary visual cortex (PVC) in the posterior tip of the occipital lobe.
- Contains map of visual space on retina (contralateral)
- Visual association: surrounds PVC, interprets visual images, recognizes faces, letters.

Auditory areas

Primary auditory cortex processes sound based on pitch, rhythm, and loudness
Auditory association area interprets sound in relation to memory (speech, words, music.

Vestibular cortex

Awareness of balance - posterior part of insula and adjacent parietal cortex (in the lateral sulcus).

Olfactory cortex

Medial aspects of temporal lobes (the uncus)
Important part of the limbic system
Responsible for conscious awareness of odors

Gustatory cortex

Located in insula
Responsible for taste perception

Visceral sensory area

Posterior to gustatory cortex
Processes visceral information

Multimodal Association Areas

Receive input from multiple senses and send output to multiple areas.
Important areas include the anterior association (prefrontal) cortex and the posterior association area.

Anterior Association Area (Prefrontal Cortex):

Complex learning, abstract thinking, personality, working memory, judgment, reasoning, persistence, planning, concern, and conscience.
Dependent on feedback from the social environment for maturation.
Closely linked to the limbic system.

Basal Nuclei

Include the caudate nucleus, putamen, and globus pallidus.
Receive input from the entire cerebral cortex, other subcortical nuclei, and one other to project to the premotor and prefrontal cortices and have influence on muscle movements.
Involved in starting, stopping, and regulating the intensity of movement.
Involve complex cognitive functions through filtering actions.

Disorders of Basal Nuclei

Huntington's disease: Too much movement.
Parkinson's disease: Too little movement.

Diencephalon

Consists of the thalamus and hypothalamus.
Encloses the third ventricle.
Thalamus: two masses of gray matter connected by the interthalamic adhesion.
- Sensory input is organized and routed to appropriate cortical regions.
Hypothalamus: involved in autonomic control, emotional responses, body temperature regulation, hunger, thirst, sleep-wake cycles, endocrine system control via releasing factors and nuclei
- Regulation of the endocrine system.

Epithalamus

Most dorsal part of the diencephalon.
Forms the roof of the third ventricle.
Includes the pineal gland.
The choroid plexus is also part of the epithalamus.

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Description

Explore the structure and function of the Central Nervous System (CNS) in this quiz. Understand how the CNS integrates information and controls voluntary and involuntary actions through its divisions. Test your knowledge on brain structures and their roles in the nervous system.