Ch. 12: Central Nervous System

Sensation

What the receptors detect

Perception

What we’re consciously aware of

Sensory neurons

AFFerent, ascend towards brain

Motor neurons

EFFerent, descend towards periphery

White matter

• Dense collections of myelinated fibers

• Conduct APs

Gray matter

Mostly neuron cell bodies, unmyelinated fibers, and dendrites

Nucleus/nuclei

Cluster of related cell bodies in CNS

Ganglia/ganglion

Cluster of cell bodies in PNS (Except basal ganglia)

Tract

Bundle of axons/fibers in CNS

Nerve

Bundle of axons/fibers in PNS

Meninges

• made of connective tissue

• Cover and protect CNS

• Protect blood vessels and enclose venous sinuses

• Contain CSF

Meninges order superficial to deep

1. Dura mater (tough)

2. Arachnoid mater (webby)

3. Pia mater (soft)

Cerebrospinal fluid

• Buoyancy - brain floats in it

• Shock absorber

• Distribute nutrients and neuroendocrine substances

• Removal of metabolic wastes

Choroid plexuses

• Contain ependymal cells

• Filter blood plasma into CSF

Blood brain barrier

• Maintain stable environment for brain

• Separates neurons from some bloodborne substances

• Astrocytes have feet that wrap around capillaries very tightly

Ventricles

• One continuous ventricle but named differently

• Lined by neuroglia, contain CSF

Meningitis

• Inflammation of the meninges

• 2 “causes” have vaccines, one doesn’t

Hydrocephalus

• Excessive CSF buildup

Cerebrum

• Frontal lobe

• Temporal lobe

• Parietal lobe

• Occipital lobe

• Also insula and limbic lobes

Cerebrum gray matter

• Cortex over cerebrum and cerebellum, as well as central portion of spinal cord

• Form nuclei deep within the brain

• Perception of info, where voluntary output descends from

White matter

• Bundles of axons form tracts that connect parts of the brain, and ascending and descending tracts of spinal cord

• Clusters of myelinated axons

Functions of cerebral cortex

• Motor: movement, speech, effect

• Sensory: vision, auditory, sensation

• Multimodal association: Associating stimuli with memories; memory, experience, action evaluation

Motor areas

• Primary motor cortex

• Pre motor cortex

• Broca’s area

Primary motor cortex

Skilled and learned voluntary movement, NOT unlearned, involuntary reflexes

Premotor cortex

• Planning motor movements

• Coordinates output from various areas

Broca’s area

• Generally in left hemisphere but slight increase in right hemisphere for lefties

• Controlling and coordinating tongue muscles

• Speech production

Sensory areas (9)

• Primary somatosensory cortex

• Somatosensory association area

• Primary visual cortex

• Visual association area

• Primary auditory cortex

• Auditory association area

• Olfactory cortex

• Gustatory cortex

• Visceral sensory area

Primary sensory cortex

XXX

Somatosensory association area

Helps determine size, texture, and context of stimuli

Primary visual cortex

Receives visual input from retina

Visual association area

Interpreting visual images, look for structure

Primary auditory cortex

Receives stimulus from ears; pitch, volume, location

Auditory association area

Associates sound with meaning

Olfactory cortex

Smell

Gustatory cortex

Taste

Visceral sensory cortex

It exists idk

Multimodal association areas

• Anterior association area

• Posterior association area

• Limbic association area

Anterior association area (AKA prefrontal cortex)

• Intellectual, learning, & executive functions- some personality

• Behavioral inhibition, working memory

Posterior association area

• Faces, patterns, & spatial awareness

Limbic association area

• Emotional nonsense and memories

Homunculus

• How many neurons the brain dedicates to certain regions

• Primary motor cortex and somatosensory cortex are somatotopically organized

Association fibers

Conduct info within a hemisphere, often primary to sensory areas

Commissural fibers

Conduct info to and from both hemispheres

Projection fibers

Connect higher and lower brain areas; afferent or efferent