Biology 227 Chapter 12 Review

Questions and Answers

Make a diagram showing the three primary (embryonic) brain vesicles. Name each and then use clinical terminology to name the resulting adult brain regions.

The brain vesicles are the forebrain, midbrain, and hindbrain.

What is the advantage of having a cerebrum that is highly convoluted?

Convolutions increase the cortical surface area, allowing more neurons to occupy the limited space.

What term is used to indicate the grooves on the cerebrum?

Sulci or fissures.

Which groove divides the cerebrum into two hemispheres?

The median longitudinal fissure. Signup and view all the answers

What divides the parietal from the frontal lobe?

The central sulcus. Signup and view all the answers

What divides the parietal from the temporal lobe?

The lateral sulcus. Signup and view all the answers

What is the function of the basal nuclei?

The basal nuclei initiate slow and sustained movement and help coordinate motor activity. Signup and view all the answers

Which basal nuclei form the striatum?

The striatum is formed by the putamen and globus pallidus. Signup and view all the answers

What arches over the diencephalon?

The caudate nucleus arches over the diencephalon. Signup and view all the answers

What does lateralization of cortical functioning mean?

It means certain functions are localized in areas on certain sides of the brain. Signup and view all the answers

Why is the term cerebral dominance a misnomer?

It only indicates which hemisphere excels at language, not overall dominance. Signup and view all the answers

Describe the role of the cerebellum in maintaining smooth, coordinated skeletal muscle activity.

The cerebellum acts like an automatic pilot by initiating and coordinating skeletal muscle activity. Signup and view all the answers

Where is the limbic system located?

On the medial aspect of each cerebral hemisphere. Signup and view all the answers

Which structures make up the limbic system?

The cingulate gyrus, parahippocampal gyrus, hippocampus, hypothalamus, mammillary bodies, septal nuclei, amygdaloid nucleus, anterior thalamic nuclei, and fornix. Signup and view all the answers

What is the function of the reticular activating system (RAS)?

It is our cortical arousal mechanism and helps keep the cerebral cortex alert. Signup and view all the answers

What is an aura?

An aura is a sensory hallucination that occurs just before a seizure. Signup and view all the answers

What is memory consolidation?

It is the process of transferring memories from short-term to long-term memory. Signup and view all the answers

List four ways in which the CNS is protected.

The bony cranium, meninges, cerebrospinal fluid, and blood-brain barrier. Signup and view all the answers

What happens if cerebrospinal fluid does not drain properly?

A condition called hydrocephalus can develop. Signup and view all the answers

How is cerebrospinal fluid formed?

CSF is formed by the choroid plexus through a secretory process. Signup and view all the answers

What is the blood-brain barrier?

It is formed mainly by capillaries with tightly joined endothelial cells. Signup and view all the answers

Define concussion.

A concussion occurs when brain injury is slight and symptoms are mild and transient. Signup and view all the answers

How do the types of motor activity controlled by the direct and indirect systems differ?

The direct pathway regulates fast and skilled movements, while the indirect pathway maintains balance and gross movements. Signup and view all the answers

What is Parkinson's disease?

A disorder caused by the degeneration of neurons in the substantia nigra leading to dopamine deficiency. Signup and view all the answers

What is a myelomeningocele?

A cyst containing parts of the spinal cord, nerve roots, and meninges that protrudes from the spine. Signup and view all the answers

What factors account for brain growth after birth?

Continued myelination of neural tissue. Signup and view all the answers

Describe cerebrovascular accident or CVA.

CVA, or stroke, occurs when blood circulation to a brain area is blocked. Signup and view all the answers

What could cause an enlarged head in infants?

Hydrocephalus is the likely diagnosis. Signup and view all the answers

What brain regions are most likely affected in Parkinson's disease?

Neurons in the substantia nigra. Signup and view all the answers

What is the treatment for Parkinson's disease?

Combination drug therapy including L-dopa and carbidopa. Signup and view all the answers

Study Notes

Brain Structure and Function

Early development of the brain includes three primary embryonic vesicles which give rise to adult brain regions.
The highly convoluted cerebrum increases cortical surface area, allowing for more neurons.
The grooves in the brain are called sulci or fissures; outward folds are termed gyri.
The median longitudinal fissure divides the cerebrum into left and right hemispheres; the central sulcus separates the frontal and parietal lobes.

Cerebral Hemispheres

The right hemisphere is associated with visual-spatial and creative abilities, while the left is more analytical.
Major functional areas include:
- Primary motor cortex: controls voluntary movements.
- Premotor cortex: manages learned motor skills.
- Somatosensory cortex: processes sensory information from the body.
- Visual and auditory areas: responsible for processing visual and auditory information.
- Prefrontal cortex: involved in thought elaboration, personality, and planning.
- Wernicke's area: language comprehension.
- Broca's area: motor function of speech.

Lateralization and Cerebral Dominance

Lateralization refers to specific functions localized to one side of the brain.
Cerebral dominance inaccurately implies one hemisphere is superior; both hemispheres communicate and integrate functions.

Basal Nuclei and Cerebellum

Basal nuclei are involved in movement coordination and control, including the striatum formed by putamen and globus pallidus.
Cerebellum maintains smooth and coordinated muscle activity, functioning like an automatic pilot through initiation and coordination.

Limbic System

Located on the medial aspect of the cerebral hemispheres, includes structures like the hippocampus and amygdala.
Plays a vital role in emotions and behavior.

Reticular Formation and Sleep

The reticular formation spans the medulla, pons, and midbrain; the reticular activating system (RAS) maintains cortical arousal.
REM sleep occupies about 25% of adult sleep time, with variations in stage depth as age increases.

Memory and CNS Protection

Short-term memory has limited capacity and duration; long-term memory has almost unlimited storage.
Memory consolidation transfers memories from STM to LTM.
CNS is protected by the bony cranium, meninges, cerebrospinal fluid (CSF), and the blood-brain barrier.

CSF Management

CSF forms in the choroid plexus and drains via arachnoid villi; improper drainage can lead to hydrocephalus, especially detrimental in adults due to cranial confines.

Concussion and Contusion

A concussion is a mild brain injury; a contusion indicates significant tissue damage.
Severe brain stem injury can impair consciousness due to RAS damage.

Spinal Cord Anatomy and Motor Control

The spinal cord extends from the skull to lumbar vertebrae and consists of gray and white matter with distinct spinal roots.
Direct pathways affect fine motor control, while indirect pathways handle balance and gross movement.

Paralysis Types

Spastic paralysis arises from upper motor neuron damage, whereas flaccid paralysis results from lower motor neuron damage.
Paraplegia affects lower limbs, hemiplegia affects one side, and quadriplegia affects all four limbs due to spinal cord injuries in various locations.

Cerebrovascular Accident (CVA)

A CVA results in blocked blood circulation, causing brain tissue death; can lead to paralysis, sensory deficits, and cognitive impairments.

Brain Development and Aging

Postnatal brain growth is primarily due to continued myelination; aging is associated with decreased brain weight and volume.

Myelomeningocele Delivery Consideration

C-section is preferred for myelomeningocele to avoid risks during vaginal delivery that could harm the cyst.

Neuroanatomy and Behavior Changes

Damage to the frontal lobes, especially the prefrontal cortex, can dramatically alter personality and behavior.

Complications of Paralysis

Complications like urinary infections, bedsores, and muscular spasms stem from loss of voluntary control and sensory input, while reflex arcs remain active.

Meningitis Diagnosis

A lumbar puncture is performed below L2 to access the subarachnoid space for cerebrospinal fluid analysis to detect infections.

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Description

Prepare for your Biology 227 exam with this comprehensive review focusing on Chapter 12. The flashcards cover key concepts such as brain vesicles, cerebrum structure, and critical terminology for adult brain regions. Use these to solidify your understanding of embryonic development and brain anatomy.