Chapter 9: Central Nervous System

Flashcards covering CNS structure, CSF, BBB, spinal cord, brainstem, cerebellum, diencephalon, sensory and motor pathways, limbic system, sleep, memory, mood, motivation, personality, and cerebral lateralization.

What are the main components of the CNS?

Neurons and supportive glial cells.

Where do interneurons reside?

Completely within the CNS.

Which neurons link interneurons to peripheral receptors and effectors?

Sensory (afferent) and efferent neurons.

What is gray matter?

Unmyelinated nerve cell bodies, dendrites, and axons.

Contains nuclei and ganglion.

What are nuclei?

Clusters of cell bodies in the CNS (brain and spinal cord).

What is a ganglion?

Cluster of nerve cell bodies outside the CNS.

What is white matter?

Myelinated axons; contains very few neuronal cell bodies.

Contains tracts.

What are tracts?

Bundles of axons that connect different regions of the CNS (equivalent to nerves in the PNS).

What is the choroid plexus?

Specialized region on the walls of the ventricles that transports ions and nutrients from the blood into the cerebrospinal fluid.

What is CSF?

A salty solution secreted into the ventricles; flows through the subarachnoid space to surround and cushion the brain and spinal cord.

How is CSF absorbed?

By arachnoid villi on the arachnoid membrane in the cranium.

What is the primary purpose of CSF?

Physical protection and chemical protection: regulating extracellular environment and removing waste.

What is a key role of CSF in waste removal?

CSF exchanges solutes with CNS interstitial fluid and provides a route to remove wastes.

Where does the spinal cord run?

Through a canal in the vertebral column.

What are the meninges?

Dura mater, arachnoid membrane, pia mater.

What is the dura mater known for?

Thickest membrane; drains blood from the brain through sinuses.

What is the subarachnoid space?

Space between arachnoid and pia containing CSF.

Which membrane adheres to the brain’s surface and contains arteries?

Pia mater.

What is a subdural hematoma?

Blood collecting in the space between the membranes, pressing on brain tissue.

What effect does a herniated disk have?

Compression of spinal nerves.

Which molecules cross the BBB easily?

Small lipid-soluble molecules.

Which brain areas lack the BBB?

Hypothalamic-hypophyseal portal system and vomiting center of the medulla.

What forms the blood-brain barrier (BBB)?

Endothelial cells with tight junctions, surrounded by astrocyte foot processes.

What is a key difference between CSF and plasma regarding proteins and cells?

CSF contains very little protein and no blood cells.

Which ions/concentrations differ in CSF compared to plasma?

CSF has Na+ similar to plasma, K+ lower, and H+ (pH) higher.

What is a spinal tap (lumbar puncture)?

Withdrawal of CSF from the subarachnoid space between the vertebrae at the lower end of the spinal cord.

What does the presence of proteins or blood in CSF suggest?

Infection (e.g., meningitis) or other pathology.

What is the spinal cord’s dorsal root responsible for?

Carrying incoming sensory information.

What is the spinal cord’s ventral root responsible for?

Carrying information from the CNS to muscles and glands.

Where do sensory fibers synapse with interneurons in the spinal cord?

Dorsal horns of the gray matter.

What do the ventral horns contain?

Cell bodies of motor neurons that carry efferent signals to muscles and glands.

What are ascending tracts?

Tracts that carry sensory information to the brain.

What are descending tracts?

Tracts that carry efferent (motor) signals from the brain to the cord.

What are propriospinal tracts?

Tracts that remain within the spinal cord.

What is the reticular formation responsible for?

Arousal, sleep, muscle tone, pain modulation; targeted by anesthesia.

What is the function of the medulla oblongata?

Control of involuntary functions (BP, breathing, swallowing, vomiting); pyramids cross the midline here.

What is the function of the pons?

Relay station for information transfer between the cerebellum and cerebrum; coordinates breathing.

What is the function of the midbrain?

Control of eye movement; relays signals for auditory and visual reflexes.

What is the cerebellum’s main function?

Process sensory information and coordinate the execution of movement; supply sensory input for coordination and balance.

What are the components of the diencephalon?

Thalamus, hypothalamus, pituitary gland, pineal gland.

What is the thalamus’ role?

Relay station and integration of sensory input.

What is the hypothalamus’ role?

Control of homeostasis, hunger, thirst, and endocrine function.

What are the posterior and anterior pituitary glands responsible for?

Posterior pituitary secretes neurohormones; anterior pituitary is an endocrine gland.

What is the pineal gland’s function?

Secretes melatonin.

What is the primary somatic sensory cortex?

Termination points of pathways from skin, musculoskeletal system, and viscera.

What are the somatosensory modalities?

Touch, temperature, pain, itch, and body position (proprioception).

What are the special senses’ cortical areas?

Visual cortex, auditory cortex, olfactory cortex, gustatory cortex.

What are association areas?

Regions that integrate information from sensory and motor areas to guide perception and actions.

What is neural plasticity?

The restructuring of brain networks in response to sensory input and experience.

What happens after sensory information reaches the appropriate cortical area?

Information is processed by association areas to form perception; the brain fills in missing information to create a complete picture.

What is cerebral lateralization (dominance)?

Left hemisphere typically handles language/verbal skills; right hemisphere handles spatial skills; dominance depends on handedness.

What are the four diffuse modulatory systems and their neurotransmitters?

Noradrenergic (norepinephrine), serotonergic (serotonin), dopaminergic (dopamine), cholinergic (acetylcholine).

What are the functions of the noradrenergic system?

Attention, arousal, sleep-wake cycles, learning, memory, anxiety, pain, mood.

What are the functions of the serotonergic system?

Sleep-wake cycle, mood and emotional behaviors (and pain/locomotion in lower nuclei).

What are the functions of the dopaminergic system?

Motor control and reward centers linked to addictive behaviors.

What are the functions of the cholinergic system?

Sleep-wake cycles, arousal, learning, memory, and sensory information passing through the thalamus.

What limbic system structures are included?

Amygdala, hippocampus, and cingulate gyrus.

What is the amygdala’s role?

Emotion and memory.

What is the hippocampus’ role?

Learning and memory.

What is the cingulate gyrus’ role?

Emotion.

What characterizes mood disorders academically?

Mood disturbances reflect CNS changes; abnormal neurotransmitter signaling; depression includes sleep/appetite changes and mood/ libido alterations; antidepressants alter synaptic transmission.

What are drives and their properties?

Drives create increased CNS arousal, goal-oriented behavior, and coordination of disparate behaviors to achieve a goal; they work with autonomic and endocrine responses.

What shapes personality?

Combination of experience and inheritance; schizophrenia has genetic and environmental influences.

What is associative learning?

Two stimuli become associated; you learn what to do and not to do.

What is non-associative learning?

Habituation (decreased response with repetition) and sensitization (increased response to certain stimuli).

What is short-term memory?

Temporary memory that fades unless rehearsed; involves working memory.

What is long-term memory?

Holds vast amounts of information; consolidation converts short-term memory to long-term memory.

What is reflexive (implicit) memory?

Autonomic memory that does not require conscious processing.

What is declarative (explicit) memory?

Memory requiring conscious attention for recall.

What are the stages of sleep and their features?

Slow-wave sleep (SWS) and rapid eye movement (REM) sleep; REM involves dreaming and sleep paralysis; sleep disorders include insomnia, sleep apnea, and somnambulism; Stage 4 is deep sleep with memory consolidation.

What controls circadian rhythms?

Suprachiasmatic nucleus of the hypothalamus; melatonin helps regulate rhythms and can be disrupted by shift work and jet lag.

What are the functions of the cholinergic system?

Sleep-wake cycles, arousal, learning, memory, and sensory information passing through the thalamus.

What limbic system structures are included?

Amygdala, hippocampus, and cingulate gyrus.

What is the amygdala’s role?

Emotion and memory.

What is the hippocampus’ role?

Learning and memory.

What is the cingulate gyrus’ role?

Emotion.

What characterizes mood disorders academically?

Mood disturbances reflect CNS changes; abnormal neurotransmitter signaling; depression includes sleep/appetite changes and mood/ libido alterations; antidepressants alter synaptic transmission.

What are drives and their properties?

Drives create increased CNS arousal, goal-oriented behavior, and coordination of disparate behaviors to achieve a goal; they work with autonomic and endocrine responses.

What shapes personality?

Combination of experience and inheritance; schizophrenia has genetic and environmental influences.

What is associative learning?

Two stimuli become associated; you learn what to do and not to do.

What is non-associative learning?

Habituation (decreased response with repetition) and sensitization (increased response to certain stimuli).

What is short-term memory?

Temporary memory that fades unless rehearsed; involves working memory.

What is long-term memory?

Holds vast amounts of information; consolidation converts short-term memory to long-term memory.

What is reflexive (implicit) memory?

Autonomic memory that does not require conscious processing.

What is declarative (explicit) memory?

Memory requiring conscious attention for recall.

What are the stages of sleep and their features?

Slow-wave sleep (SWS) and rapid eye movement (REM) sleep; REM involves dreaming and sleep paralysis; sleep disorders include insomnia, sleep apnea, and somnambulism; Stage 4 is deep sleep with memory consolidation.

What controls circadian rhythms?

Suprachiasmatic nucleus of the hypothalamus; melatonin helps regulate rhythms and can be disrupted by shift work and jet lag.

How does the CSF provide physical protection?

Buoyancy of CSF reduce the weight of the brain nearly 30-fold

Lighter weight means less pressure on the blood vessels attached to the CNS.

Protective padding when there is a blow to the head, CSF must be compressed before the brain can hit the inside of the cranium.

What are the oxygen and glucose needs of the brain?

The brain receives 15% of the blood pumped by the heart and 50% of the glucose.

How is dopamine correlate to Parkinson’s?

Dopamine is a neurotransmitter that plays a crucial role in regulating movement, and in Parkinson's disease, there is a significant loss of dopamine-producing neurons in the brain, leading to motor symptoms such as tremors and stiffness.

What are the components of the brain stem?

Reticular formation

Medulla Oblongata

Pons

Midbrain

What are the components of the Diencephelon?

Thalamus

Hypothalammus

Pituitary gland

Pineal gland

What are the componenets of the primary somatic sensory cortex?

Touch (mechanoreceptors)

Temperature (termoreceptors)

Pain (nociceptors)

Itch (proprioceptors)

What are the areas of the cerebral cortex?

Sensory area

Motor area

Association area

What is the sensory area of the cerebral cortex?

The sensory area receives sensory input and translates it into perception (awareness)

What is the motor area of the cerebral cortex?

directs skeletal muscle movement

What is the association area of the cerebral cortex?

Integrates information from sensory and motor areas can direct voluntary behavior

What is cerebral lateralization?

Left or right brain dominant

What are receptors in the spinal cord?

Nociception,

What are receptors in the medulla?

Fine touch, proprioception, vibration