Nervous System: The Brain — Overview, Development, and Gray & White Matter

Question-and-answer flashcards covering brain anatomy, development (neurulation and vesicles), gray vs white matter, PNS components, higher-order functions, EEG, sleep, memory, emotion, and language.

What are the four major brain regions?

Cerebrum, diencephalon, brainstem, and cerebellum.

How many hemispheres and lobes does the cerebrum have per hemisphere?

Two hemispheres; five lobes per hemisphere (frontal, parietal, temporal, occipital, and insular).

What are gyri, sulci, and fissures?

Gyri are ridges on the brain surface; sulci are depressions between ridges; fissures are deep sulci.

In brain orientation, what do anterior and posterior correspond to?

Anterior = rostral; posterior = caudal.

When does neurulation begin?

In the third week of embryonic development.

What forms the neural tube and what induces it?

The thick neural plate forms; the notochord beneath induces the neural plate to form the neural tube.

What is the neural crest’s role during neurulation?

The tips of neural folds become neural crest cells, which separate from the neural folds.

What are neuropores?

Openings at the cranial and caudal ends of the neural tube that close by the end of the 4th week.

What vitamins reduce the risk of neural tube defects?

Vitamin B12 and folate during pregnancy.

What is anencephaly?

Substantial or complete absence of a brain; the infant dies soon after birth.

What is spina bifida cystica?

Almost no formation of the vertebral arch; a large cyst in the back; often causes paralysis of the lower limbs.

What is spina bifida occulta?

Partial defect of the bony arch; less serious; more common.

What are the primary brain vesicles and their names?

Prosencephalon (forebrain), Mesencephalon (midbrain), Rhombencephalon (hindbrain).

Which primary brain vesicle becomes the forebrain?

Prosencephalon.

What does the telencephalon become?

The cerebrum.

What does the diencephalon become?

The thalamus, hypothalamus, and epithalamus.

What does the mesencephalon become?

The midbrain.

What does the metencephalon become?

The pons and cerebellum.

What does the myelencephalon become?

The medulla oblongata.

What happens to brain development between weeks 13 and 26?

The telencephalon envelops the diencephalon and surface folds develop.

By birth, what is true about gyri and sulci?

Most gyri and sulci are present by birth.

What is gray matter, and what is it made of?

Gray matter is composed of neuron cell bodies, dendrites, and unmyelinated axons; the cortex is gray matter.

What is a nucleus in the CNS?

A region of gray matter (cluster of cell bodies) near the surface or deep within the brain.

What is white matter, and what is it composed of?

White matter consists of myelinated axons organized in bundles called tracts; peduncles connect brain regions; funiculi are spinal cord subdivisions.

What are ganglia, nerves, and nerve plexuses?

Ganglia are aggregates of neuron cell bodies in the PNS; nerves are bundles of axons; a nerve plexus is a network of nerves.

Define a pathway in the nervous system.

A sequence of two or more neurons that connects the CNS to the body.

What are higher-order brain functions and where do they occur?

Learning, memory, and reasoning; occur within the cortex of the cerebrum and involve multiple brain regions; both conscious and subconscious processing.

What is an EEG and which waves are associated with wakefulness vs sleep?

An EEG records brain activity via head electrodes; alpha and beta waves are common in wakefulness; delta and theta waves are common in sleep.

What are REM and non-REM sleep?

Non-REM sleep involves slower EEG frequencies and makes up about 75% of sleep; REM sleep features rapid eye movements, brain activity, and dreams, making up about 25% of sleep.

How does sleep duration vary by age?

Infants: 17–18 hours; Teens: 8.5–9.5 hours; Adults: 7–8 hours.

What is cognition and which brain areas are involved?

Cognition is the mental processes of awareness, knowledge, perception, memory, and thinking; association areas of the cerebrum and especially the frontal lobe are important.

Describe sensory memory, short-term memory, and long-term memory.

Sensory memory lasts seconds; short-term memory has about seven items capacity and seconds-to-hours duration; long-term memory can be encoded from short-term memory with repetition and may last indefinitely.

Which brain regions are involved in emotion and language?

Emotion is interpreted by the limbic system and expression is controlled by the prefrontal cortex; language involves Wernicke’s area (interpretation) and Broca’s area (motor speech) with the primary motor cortex executing speech.

What are Wernicke’s area and Broca’s area responsible for?

Wernicke’s area interprets language; Broca’s area initiates the speech motor program; primary motor cortex signals motor neurons to produce speech.