Central Nervous System (CNS) Review

A comprehensive set of vocabulary flashcards focusing on key terms and definitions related to the Central Nervous System.

Central Nervous System

Composed of the brain and spinal cord, responsible for behavior, personality, and intellect.

Rostral

Directional term meaning toward the nose/forehead.

Caudal

Directional term meaning toward the tail.

Gray Matter

Outer layer of the brain, composed mainly of neuronal cell bodies and dendrites.

White Matter

Inner layer of the brain, primarily composed of myelinated axons.

Cerebral Cortex

2-4 mm thick layer of gray matter that allows consciousness and higher brain functions.

Gyri

Elevated ridges on the surface of the cerebrum.

Sulci

Shallow grooves that separate gyri on the surface of the cerebrum.

Cerebrum

The largest part of the brain, divided into two hemispheres.

Transverse Cerebral Fissure

Separates the cerebral hemispheres from the cerebellum.

Longitudinal Fissure

Separates the right and left cerebral hemispheres.

Cerebral Hemispheres

Two halves of the cerebrum, making up approximately 80% of total brain mass.

Primary Motor Cortex

Located on the precentral gyrus, initiates voluntary movement.

Primary Somatosensory Cortex

Located on the postcentral gyrus, perception of general somatic sensations.

Occipital Lobe

Lobe of the brain responsible for primary visual processing.

Temporal Lobe

Lobe of the brain responsible for primary auditory processing.

Insula

Fifth lobe of the cerebrum, responsible for taste and balance.

Basal Nuclei

Clusters of neuronal cell bodies in the brain that help control motor activity.

Thalamus

Relay station for sensory information, forms part of the diencephalon.

Hypothalamus

• controls ANS

• regulates sleep/wake cycles

• controls the endocrine system

• regulates body temperature

• controls motivational behavior

• regulates hunger and thirst

Epithalamus

Part of the diencephalon that includes the pineal gland.

Pineal Gland

Secretes melatonin, involved in sleep regulation.

Midbrain

Most rostral part of the brainstem, involved in visual and auditory reflexes.

• superior colliculi: Visual Reflex

• inferior colliculi: auditory reflex

Pons

Links the brainstem with the cerebellum, involved in motor control.

• Fine tunes respiration

• motor axons pass through

Medulla Oblongata

Regulates vital autonomic functions such as heart rate and breathing.

• pyramids: motor and sensory axon crossing midline

• cardiac: vasomotor center

• respiratory center

Cerebellum

• Coordinates body movements

• maintains posture and balance.

• stores motor memories

Cerebrospinal Fluid (CSF)

Fluid that cushions the brain and spinal cord and provides nutrients.

Meninges

Three protective membranes covering the brain and spinal cord.

Dura Mater

Outermost, toughest layer of the meninges.

Arachnoid Mater

Middle layer of the meninges, contains subarachnoid space filled with CSF.

Pia Mater

Innermost layer of the meninges, closely adheres to the brain.

Blood-Brain Barrier (BBB)

Protective barrier that prevents certain substances from entering the brain.

Neuroglia

Supportive cells that maintain homeostasis and protect neurons.

Motor Pathways

Descending tracts that carry motor commands from the brain to the body.

Sensory Pathways

Ascending tracts that carry sensory information from the body to the brain.

Hippocampus

Region of the brain involved in memory consolidation.

Short-term Memory

Temporary storage of information lasting minutes to hours.

Long-term Memory

Permanent storage of information lasting days to years.

Consolidation

The process of transitioning a short-term memory into long-term memory.

Sleep

State of partial unconsciousness with altered brain activity.

we have two types:

REM and NREM

Electroencephalogram (EEG)

Recording of electrical activity in the brain.

Limbic System

Part of the brain involved in emotional responses and memories.

Reticular Formation

Network of neurons that regulates wakefulness and alertness.

Cerebral Aqueduct

Structure that connects the third and fourth ventricles.

Cerebral Nuclei

Clusters of neurons within the cerebral white matter.

Interventricular Foramen

Connects the lateral ventricles to the third ventricle.

Septum Pellucidum

Thin membrane that separates the lateral ventricles.

Vermis

Connective tissue structure that links the two cerebellar hemispheres.

Autonomic Nervous System (ANS)

Part of the nervous system that controls involuntary bodily functions.

Four general functions of the Brain Stem

1. Acts as a passage way for all fibers running between the cerebrum and spinal cord

2. It is important in the innervation of the face and head; 10/12 cranial nerves (CN) attach to the brainstem

3. it produces programmed, automatic behaviors necessary for survival

4. it is a major site for integration of auditory and visual reflexes

Ventricles

are fluid-filled cavities within the brain that produce and contain cerebrospinal fluid (CSF), providing cushioning and support.

Lateral ventricles

The largest of the brain's ventricles, which are responsible for producing cerebrospinal fluid and are located in each hemisphere of the brain.

Third ventricle

lies in the diencephalon; it is connected to the lateral ventricles by the interventricular foramen

cerebral aqueduct

is a narrow channel connecting the third and fourth ventricles of the brain, allowing the flow of cerebrospinal fluid.

Fourth ventricle

located between the brainstem and cerebellum, this ventricle connects the cerebral aqueduct with the central canal of the spinal cord.

What protects the brain?

The brain is protected by the skull and three layers of membranes called meninges, along with cerebrospinal fluid that cushions it.

periosteal layer

It is a sublayer of the dura mater it attaches to the periosteum of the skull

meningeal layer

It is the inner sublayer of the dura mater that forms that external covering of the brain

subarachnoid space

The space between the arachnoid mater and pia mater, containing cerebrospinal fluid. It is full of web-like threads that connect the arachnid to the Pia mater

Arachnoid Villi (granulations)

Knob-like structures that project into the superior sagittal sinus. CSF passes through these sinuses

Function of the Cerebrospinal Fluid (CSF)

1. The brain and the spinal cord float in the CSF, which cushions them from hard blows and sudden jolts

2. The CSF also provides nutrients to the brain and spinal cord, helps remove wastes produced by neurons

   1. carries chemical signals between various parts of the CNS

Choroid Plexus

A network of cells in the ventricles of the brain that produces cerebrospinal fluid (CSF). It plays a critical role in the maintenance of the blood-CSF barrier and regulates the composition of CSF.

Choroid Plexus

It is composed of modified ependymal cells in association with capillaries

What does the Blood Brain Barrier (BBB) let through?

The Blood Brain Barrier (BBB) selectively allows certain substances, such as water, glucose, and essential amino acids, to pass through while blocking harmful pathogens and toxins from entering the brain. (Lipid soluble molecules)

The BBB is composed of:

endothelial cells, tight junctions, and astrocytes.

Limbic System

a group of interconnected structures involved in emotions, memory, and learning, including the hippocampus and amygdala.

Fornix

fiber tract that links limbic system regions

Amygdoloid body

Recognizes angry or fearful facial expression, assesses danger, elicits fear response, and stores emotional memories

Cingulate Gyrus

Plays a role in expressing emotions via gestures and resolves mental conflict

Reticular Formation

Network of neurons throughout the brain stem that receives input from various structuresand helps regulate consciousness, alertness, and arousal.

Reticular Activating System (RAS)

Part of the reticular formation that plays a crucial role in controlling wakefulness and the sleep-wake cycle. It filters incoming stimuli to focus attention.

Rapid Eye Movement (REM)

A sleep stage characterized by vivid dreams, rapid movement of the eyes, and increased brain activity.

Non-Rapid Eye Movement

(NREM) sleep stage defined by slower brain waves, reduced eye movement, and no vivid dreams, serving as a restful period that prepares the body for REM sleep.

Memory Trace

neural change responsible for tension or storage of knowledge

Spinal Cord

Part of the CNS, extending from the foramen magnum to the L1 or L2

How many segments does a spinal cord have?

Consist of 31 segments that include cervical, thoracic, lumbar, sacral, and coccygeal regions.

Conus medullaris

The tapered end of the spinal cord, located near the L1 or L2 vertebrae.

cauda equina (“horses tail”)

Collection of nerves at the end of the spinal cord

Functions of the Spinal Cord

1. Responsible for sensory and motor innervation of body inferior to the head

2. provides a 2 way conduction pathway for signals between the body and the brain

3. Major integration center for reflexes