Central Nervous System White vs gray matter :: Gray = cell bodies (processing); White = myelinated axons (communication) Primary motor cortex, Broca’s, premotor location :: Frontal lobe Innermost meninge :: Pia mater CSF is formed where :: Choroid plexus (ventricles) Ventral horn destruction causes :: Loss of motor output Same hemisphere fibers :: Association fibers Across hemispheres :: Commissural fibers (corpus callosum) Advantage of convolutions :: Increased surface area → more processing power Grooves :: Sulci Folds :: Gyri Groove dividing hemispheres :: Longitudinal fissure Frontal vs parietal lobe :: Central sulcus Parietal vs temporal :: Lateral sulcus Primary motor cortex :: Voluntary movement Premotor cortex :: Plans movement Primary sensory cortex :: Detects touch Somatosensory association :: Interprets sensation Visual area :: Vision Auditory area :: Hearing Prefrontal cortex :: Decision making/personality Broca’s area :: Speech production Controls temp, hunger, ANS :: Hypothalamus Substantia nigra location :: Midbrain Vital centers (heart, breathing) :: Medulla oblongata Sensory relay center :: Thalamus (gray matter) Basal nuclei function :: Initiate/stop movement, smooth motion Cerebellum role :: Coordination, balance, posture Limbic system location/function :: Around brainstem; emotion + memory RAS meaning/function :: Reticular Activating System; alertness STM → LTM factors :: Repetition, sleep, emotion, meaning CNS protection (4) :: Skull/vertebrae, meninges, CSF, BBB CSF formation/drainage :: Produced in ventricles → circulates → reabsorbed into blood Blood-brain barrier :: Tight capillaries + astrocytes Pyramidal tracts :: Motor pathways; cross at medulla Dorsal vs ventral roots :: Dorsal = sensory; Ventral = motor CSF location :: Subarachnoid space Spinal cord organization :: Gray inside; white outside Anterior vs posterior root signals :: Anterior = motor; Posterior = sensory Cervical/lumbar enlargements :: Serve limbs Spinal cord location :: Vertebral foramen Filum terminale :: Anchors spinal cord ⸻ Sensation & Integration Sensation vs perception :: Sensation = detection; Perception = interpretation Sensory modality :: Type of stimulus Mechanoreceptors :: Touch/pressure Thermoreceptors :: Temperature Chemoreceptors :: Chemicals Nociceptors :: Pain Naked nerve endings :: Free endings (pain/temp) Encapsulated endings :: Wrapped (touch/pressure) 3 steps of sensation :: Stimulus → receptor → signal to brain Meissner’s corpuscles :: Light touch receptors Proprioceptor example :: Muscle spindle; detects stretch/body position Pressure receptor :: Pacinian corpuscle (encapsulated) Thermal receptor distribution :: Uneven Touch receptor distribution :: Uneven Referred pain :: Pain felt elsewhere Pain receptors :: Nociceptors Brain maps based on :: Sensitivity (not size) 3-neuron sensory pathway :: 1st: receptor → spinal cord 2nd: spinal cord → thalamus 3rd: thalamus → cortex Motor pathway neurons :: 2 neurons Upper: brain → spinal cord Lower: spinal cord → muscle Ascending pathways :: Sensory to brain Descending pathways :: Motor from brain

Gray matter

Contains cell bodies and is involved in processing information.

White matter

Consists of myelinated axons and is responsible for communication between brain regions.

Primary motor cortex location

Located in the frontal lobe, involved in voluntary movement.

Broca’s area function

Responsible for speech production.

Pia mater

The innermost layer of the meninges.

Choroid plexus

The structure in the ventricles where cerebrospinal fluid (CSF) is formed.

Ventral horn destruction effect

Leads to loss of motor output.

Association fibers

Connect fibers within the same hemisphere of the brain.

Commissural fibers

Connect fibers across hemispheres; exemplified by the corpus callosum.

Advantage of convolutions in the brain

Increased surface area leading to greater processing power.

Sulci

Grooves in the brain's surface.

Gyri

Folds in the brain's surface.

Longitudinal fissure

A groove that divides the brain into hemispheres.

Central sulcus

Divides the frontal lobe from the parietal lobe.

Lateral sulcus

Divides the parietal lobe from the temporal lobe.

Primary sensory cortex function

Detects touch.

Somatosensory association area function

Interprets sensation.

Visual area function

Responsible for vision.

Auditory area function

Responsible for hearing.

Prefrontal cortex function

Involved in decision-making and personality.

Hypothalamus function

Regulates temperature, hunger, and the autonomic nervous system.

Substantia nigra location

Found in the midbrain.

Medulla oblongata function

Contains vital centers for heart rate and breathing.

Thalamus function

Acts as a sensory relay center.

Basal nuclei function

Initiate and stop movement, and ensure smooth motion.

Cerebellum role

Coordinates balance and posture.

Limbic system location/function

Surrounds the brainstem and is involved in emotions and memory.

Reticular Activating System (RAS) function

Regulates alertness.

Factors for STM to LTM conversion

Repetition, sleep, emotion, and meaning.

CNS protection structures

Skull, vertebrae, meninges, cerebrospinal fluid (CSF), and blood-brain barrier (BBB).

Cerebrospinal fluid (CSF) formation process

Produced in the ventricles, circulates, and is reabsorbed into the blood.

Blood-brain barrier (BBB) composition

Composed of tight capillaries and astrocytes.

Pyramidal tracts function

Motor pathways that cross at the medulla.

Dorsal root function

Sensory input.

Ventral root function

Motor output.

CSF location

Found in the subarachnoid space.

Spinal cord organization

Gray matter is inside; white matter is outside.

Anterior root function

Transmits motor signals.

Posterior root function

Transmits sensory signals.

Cervical/lumbar enlargements purpose

Serve the limbs.

Spinal cord location

Located within the vertebral foramen.

Filum terminale function

Anchors the spinal cord.

Sensation vs perception distinction

Sensation is the detection of stimuli; perception is the interpretation of stimuli.

Sensory modality definition

The type of stimulus detected.

Mechanoreceptors role

Respond to touch and pressure.

Thermoreceptors role

Detect temperature changes.

Chemoreceptors role

Respond to chemical stimuli.

Nociceptors role

Detect and respond to pain.

Naked nerve endings function

Free endings that detect pain and temperature.

Encapsulated endings function

Wrapped nerve endings that detect touch and pressure.

Steps of sensation

Stimulus, receptor, then signal to the brain.

Meissner’s corpuscles role

Receptors for light touch.

Proprioceptor example

Muscle spindle, which detects stretch and body position.

Pressure receptor example

Pacinian corpuscle, which is encapsulated.

Distribution of thermal receptors

Uneven across the body.

Distribution of touch receptors

Uneven across the body.

Referred pain definition

Pain felt in a region other than the site of injury.

3-neuron sensory pathway process

1st: from receptor to spinal cord; 2nd: from spinal cord to thalamus; 3rd: from thalamus to cortex.

Motor pathway neuron count

Contains 2 neurons (upper from brain to spinal cord, lower from spinal cord to muscle).

Ascending pathways role

Transmit sensory information to the brain.

Descending pathways role

Transmit motor commands from the brain.