Name: __________________________________________________
Central Nervous System – The Spinal Cord & Brain
Region Structures Description/Location Special areas or parts contained
in this structure?
Function(s)
Protective structures of Spinal Cord & Brain
Dura mater Outermost covering; leathery connective tissue; surrounded by an epidural space in the spinal cord
One layer (periosteal layer) attaches to skull; second layer (meningeal layer) covers brain and continues as dura mater of spinal cord
protects
Arachnoid mater
Middle meningeal layer; “cob webby”
Arachnoid villi – protrude through dura mater – absorbs CSF into venous blood
Threadlike extensions span subarachnoid space (filled with CSF and blood vessels)to attach it to the pia mater
Pia mater Clings tightly to surface of brain and spinal cord
protects
Cerebrospinal fluid
Watery broth similar to blood plasma – contains less protein and more vitamin CFormed by blood of choroid plexus (made by ependymal cells)
Forms and drains at a constant rate so that pressure and volume are maintained; changes in pressure/vol = pathology
Watery cushion that protects
Meninges
The Blood-Brain Barrier
Composed of least permeable capillaries in body
Passes only water, glucose, and essential amino acids. Most wastes, toxins, proteins, and drugs are prevented from passing. But fat soluble chemicals can pass (b/c membrane is fat) – alcohol, nicotine, and anesthetics can affect brain
Region Structures Description/Location Special areas or parts contained
in this
Function(s)
Name: __________________________________________________
structure?Spinal cord – Spinal nerves
Posterior (dorsal) root ganglion and root
Dorsal roots fuse with ventral roots to form spinal nerves on periphery of spinal cord
Have cell bodies and sensory fibers that lead to dorsal horns; If damaged – loss of sensation from a body area
Anterior (ventral) root
Same Contain axons of motor neurons; If damaged – flaccid paralysis of muscle (atrophy)
Spinal cord – Gray matter
Posterior (dorsal) horns
Part of the “H” shape in middle of cord (unmyelinated fiber tracts); two posterior projections of gray matter
Contains interneurons
Anterior (ventral) horns
Part of the “H” shape in middle of cord (unmyelinated fiber tracts); two anterior projections
Contain cell bodies of motor neurons of somatic nervous system
Central canal Oval opening in center of spinal cord surrounded by gray matter
Contains CSF
Spinal cord – White matter
Posterior (dorsal) column
White matter made of myelinated axonal fiber tracts
Has ascending tracts Carries sensory input (touch, position, and pressure) to brain
Lateral column White matter made of myelinated axonal fiber tracts
Has ascending tracts and descending tracts
Carries sensory input (pain and temperature) to brain;Maintains muscle tone and skilled movements (esp. hands)
SpinalcordAnterior (ventral) column
White matter made of myelinated axonal fiber tracts
Has ascending tracts and descending tracts
Carries sensory input (body position) to brain;Maintains tone & trunk muscle movement
Region Structures Description/Location Special areas or parts contained
in this structure?
Function(s)
Name: __________________________________________________
Brain - Cerebral hemispheres (cerebrum)
Cerebral cortex
Superficial layer (2-4 mm thick) of cerebrum that is gray matter (unmyelinated fiber tracts); lots of folds
Has gyri – ridges; sulci – shallow grooves; and fissures – deep grooves (ie. central & longitudinal)
Houses billions of neurons which are involved in speech, memory, logic, emotion, movement
Frontal lobe (“higher order brain”)
Anterior to the central sulcus Premotor area and Primary motor cortex; Prefrontal area; Broca’s area (left side only)
Plans movement and consciously controls skeletal muscle (face, mouth, hands); regulates motivation and emotional behavior/mood; vocalizes words and interprets word meanings
Damage to Broca’s area - inability to produce meaningful language
Parietal lobes Paired lobes on both sides of the longitudinal fissure; separated from frontal lobe by central sulcus; separated from each other by longitudinal fissure
Somatic sensory cortex, Gustatory area; Speech area
Interprets sensory stimuli (pain, temperature, touch, taste); sound out words
Occipital lobe Posterior part of brain Visual cortex Receives and interprets visual stimuli
Temporal lobe Paired lobes under the temporal bones; below lateral fissure
Auditory area; Olfactory area; Wernicke’s area (left side only), Memory area
Interprets characteristics of sound like pitch and rhythm; determines if sound is speech, music, or noise; also, meaning of speech; receives impulses related to smell
Damage to Wernicke’s area – inability to understand language
Name: __________________________________________________
Cerebral white matter
Deep to the cerebral cortex w/ myelinated fiber tracts that run in 3 directions
Association fibers, Commissural fibers (corpus callosum), Projection fibers
Transmit impulses in same hemisphere (Association), across to other hemisphere (commissural), to other areas like spinal cord (projection)
Basal nuclei Islands of gray matter in the white matter area
Corpus striatum – made of caudate nucleus and lenticular nucleus
Receives vol. motor input and provides output to cerebral cortex, thalamus, and hypothalamus; helps maintain muscle tone and posture
Damage to basal nuclei – Parkinson’s and cerebral palsy
Limbic System (“emotional brain”)
Encircling the brain stem on the inner border of cerebrum
Hippocampus, cingulate gyri, amygdala, olfactory bulbs, & mammillary bodies
Governs emotional aspects of behavior, memory, rage, pleasure, and pain as related to survival; responds to olfactory stimulation
Region Structures Description/Location Special areas or parts contained
in this structure?
Function(s)
Brain - Diencephalon
Epithalamus Forms the roof of the third ventricle; highest part of the diencephalon
Pineal gland (“pine cone”),Choroid plexus of third ventricle
Pineal gland secretes melatonin (promotes sleepiness, sets timing of body’s biological clock); in sheep, contributes to seasonal breeding capabilityChoroid plexus have capillaries (covered by ependymal cells) that form CSF from blood plasma
Thalamus(80% of diencephalon)
Forms the superior part of the lateral walls of the third ventricle; encloses the third ventricle; below somatic sensory area
Interthalamic adhesion crosses the third ventricle to join the right and left portions of thalamus
Relays sensory impulses from the spinal cord to the sensory cortex (pleasant and unpleasant sensations: pain, temperature, pressure, emotions/memory, maybe cognitive function)
Hypothalamus (major regulator of
Forms the inferior part of the lateral walls and floor of the third ventricle; “under the thalamus,” autonomic nervous sys center
Mammillary bodies,Infundibulum (attaches to pituitary gland which secretes GH, LH, and
Relay reflexes related to sense of smell; controls Autonomic Nervous Sys (heart rate, digestive and bladder function); Produces hormones (oxytocin and ADH)
Name: __________________________________________________
homeostasis) FSH) and controls pituitary gland; with limbic system, regulates feelings of rage, pain, and pleasure; regulates hunger and thirst; controls body temperature; establishes daily patterns of sleep
Brain – Brain Stem
Reticular formation
Gray matter in the larger portion of the brain stem
Reticular Activating System (RAS)
Regulates cyclical motor functions – respiration, walking, and chewing; RAS maintains consciousness and awakening from sleep
Damage to reticular formation - comaMidbrain Extends from pons to
diencephalon (about 2.5 cm); Colliculi; Cerebral peduncles; Cerebral aqueduct pass through connecting third ventricle to fourth ventricle;Nuclei of origin for cranial nerves III and IV
Colliculi = respond to visual stimuli (visual reflexes) and auditory stimuli; Cerebral peduncles = convey ascending and descending impulses from cerebral cortex to pons, medulla, and spinal cord
Pons (“bridge”)
Superior to medulla and anterior to the cerebellum (about 2.5 cm long)
Nuclei of origin for cranial nerves V, VI, VII, and VIII
Connects spinal cord and medulla to the midbrain; also helps control breathing, swallowing, balance, chewing, and salivation
Medulla oblongata
Begins at the foramen magnum and extends upward to pons (about 3 cm long); inferiorly, it merges with brain stem
Pyramids – involved in conscious control of muscles; Nuclei of origin for cranial nerves VIII, IX, X, XI, and XII
Regulates vital visceral activities, such as rate and force of heartbeat & diameter of blood vessels (bp), breathing, swallowing, vomiting, coughing, sneezing, and hiccuping
Brain – Cerebellum
Brain
Cerebellum Posterior to medulla and pons; inferior to the posterior portion of cerebrum (separated by transverse fissure); shaped like a butterfly – vermis is constricted area
Cerebellar cortex (gray matter), arbor vitae (white matter)
Provides precise timing for skeletal muscle activity, controls balance and equilibrium, and regulates posture
Name: __________________________________________________
Name: __________________________________________________
Name: __________________________________________________
Name: __________________________________________________
Name: __________________________________________________
Name: __________________________________________________
Name: __________________________________________________