the brain Flashcards
the brains four major regions
cerebral hemispheres, diencephalon (di″en-sef′ah-lon), brain stem, and cerebellum
Q: What are gyri, sulci, and fissures in the cerebrum?
Gyri: Elevated ridges of tissue on the surface of the cerebrum.
Sulci: Shallow grooves that separate the gyri.
Fissures: Deeper grooves that separate large regions of the brain.
The longitudinal fissure separates the cerebral hemispheres.
Other fissures and sulci divide each hemisphere into lobes, named for the cranial bones above them.
Q: What are the three basic regions of each cerebral hemisphere?
Superficial Cortex (Gray Matter): The outer layer of the cerebrum, which appears gray in fresh brain tissue. It is involved in higher functions like thinking, memory, and voluntary movement.
Internal White Matter: The area beneath the cortex, made up of myelinated nerve fibers that carry communication between different brain regions.
Basal Nuclei (Gray Matter): Islands of gray matter deep within the white matter that help control motor activities and coordination.
What is the function of the primary somatic sensory area in the cerebral cortex, and what is the sensory homunculus?
The primary somatic sensory area is located in the parietal lobe, behind the central sulcus, and it is responsible for receiving and interpreting sensory information like pain, temperature, and touch from the body.
The sensory homunculus is a map that shows how much brain tissue is devoted to different parts of the body based on the density of sensory receptors. Areas like the lips and fingertips, which have more sensory receptors, take up more space in this map.
The sensory pathways are crossed: the left side of the brain processes information from the right side of the body, and the right side processes information from the left side.
However, it is important to note that the somatosensory cortex primarily processes the physical aspects of pain, such as:
Where the pain is coming from (e.g., which part of the body).
What type of sensation it is (e.g., sharp, throbbing, burning).
How intense the pain is.
But, the emotional and psychological aspects of pain, such as the distress or discomfort it causes, are processed by other areas, like the limbic system.
The cerebral cortex is the entire outer layer of the cerebrum, while the hemispherical cortex refers to the cortex of a specific hemisphere (left or right) of the brain.
Q: Where are the special sense areas located in the brain?
Visual area: Occipital lobe (posterior part).
Auditory area: Temporal lobe (bordering the lateral sulcus).
Olfactory area: Deep in the temporal lobe.
Where is the primary motor area located and what does it do?
Location: In the frontal lobe, anterior to the central sulcus.
Function: Controls voluntary movements of skeletal muscles.
What is the pyramidal tract and what does it do?
The pyramidal tract (or corticospinal tract) carries motor signals from the primary motor area to the spinal cord for voluntary movement.
The pyramidal tract is crucial for fine, skilled movements, such as writing, typing, or playing an instrument. It is part of the descending motor pathways that allow for precise and controlled muscle actions.
What is the motor homunculus?
The motor homunculus is a visual map that shows the upside-down and crossed representation of the body on the primary motor cortex, with more space dedicated to body areas requiring fine motor control (e.g., face, hands).
What is Broca’s area and what happens if it’s damaged?
Location: In the frontal lobe, at the base of the precentral gyrus.
Function: Helps with speech production.
Damage: Causes difficulty in speaking but not in understanding speech (Broca’s aphasia).
What does the anterior association area in the frontal lobe control?
: It’s involved in higher intellectual reasoning and social behavior, and also helps with language comprehension.
Q: What is the posterior association area and what does it do?
Located in the posterior cortex.
Involved in recognizing patterns, faces, and blending sensory inputs to understand the whole situation.
Contains the speech area to help sound out words.
Sensory Integration: It helps integrate sensory information from multiple sources, such as vision, touch, and hearing, to create a comprehensive understanding of the environment. This allows you to interpret and respond to sensory stimuli more effectively.
Spatial Awareness and Navigation: The posterior association area plays a key role in spatial awareness, which helps you understand where objects are in space relative to your body. It’s crucial for tasks like navigating through the environment, recognizing faces, and understanding movement.
Language Processing: This area contributes to language comprehension, especially the integration of visual and auditory information. It’s linked to areas involved in understanding written and spoken language, such as Wernicke’s area, which is in the left temporal lobe.
Attention and Perception: The posterior association area helps with directing attention to important stimuli and filtering out irrelevant information. It also supports perceptual processing, helping you make sense of complex sensory inputs (e.g., recognizing a face or interpreting a visual scene).
