A&P Central Nervous System

Cerebrum and Diencephalon

midbrain of brainstem

brainstem and cerebellum

• Includes the brain and spinal cord• Act as the integration centers of the nervous system

Largest brain region, divided into two hemispheres by longitudinal fissure• hemisphere is associated with the opposites side of the body (contralateral)• Location of the conscious mind, including awareness, communication, memory, and voluntary movements• Folding forms elevated ridges called gyri and grooves called sulci• contains Cerebral cortex & Gray matter

the outer layer of gray matter of cerebrum

nervous tissue containing neuron somas, dendrites, and neuroglia

1.Frontal2.Paretal

3.Temporal

4.Occipital

5.Insula

primary motor cortex - voluntary movements of skeletal muscles; Broca’s area – motor control of speech

cerebrum

primary somatosensory cortex – receives info from receptors in skin, muscles, joints

cerebrum

primary auditory cortex and olfactory cortex processing senses ofhearing and smell

cerebrum

primary visual cortex- processing sense of sight

gustatory cortex – processing sense of taste; vestibular cortex – processing balance; visceral sensory area – receives info from organ receptors

nervous tissue containing bundles of myelinated axons (tracts)

• Deep to the gray matter of the cortex• Functions as lines of communication

cerebral white matter that connect gyri/lobes within a hemisphere

cerebral white matter that connect the two hemispheres

ex.- Corpus callosum

connect cerebrum to spinal cord

ex.- Decussation of pyramids – the crossing of tracts in the brainstem, leading to contralateral control

clusters of gray matter located within the cerebral white matter• Function in the starting, stopping, and monitoring of voluntary muscle movements• Coordinates subconscious muscle movements, e.g. rhythm of leg and arm swing movements during walking• Also includes the Amygdala which regulates mood

region of the forebrain that is surrounded by the cerebrum. Includes the paired Thalamus, Hypothalamus, and Epithalamus

Thalamus

Hypothalamus

Epithalamus

paired egg-shaped nuclei• ‘gateway to the cerebral cortex’• Directs sensory impulses to the appropriate area of the cerebral cortex

area of nuclei below the thalamus• Regulates homeostasis, including body temp, hunger, thirst, hormone levels,emotions, and sleep-wake cycles• The pituitary glands hangs from, and is influenced by, the hypothalamus

largely composed of the Pineal Gland, secretes melatonin hormonethat regulates sleep-wake cycles

‘stalk’ of brain forming connection to the spinal cord• Includes the midbrain, pons, and medulla oblongata

midbrain

pons

medulla oblongata

Midbrain – region at the top of the brainstem

contains cerebral peduncles & tectal plate

contain tracts connecting the cerebral hemispheres to the spinal cord

- Superior colliculi – visual reflex center, coordinating head and eye movements- Inferior colliculi – auditory reflex center, coordinating sound location and startling

region at the center of the brainstem, bulging anteriorly• Contains tracts running to and from the spinal cord• Function - contains nuclei that help regulate breathing,smoothing out the transitions between inspiration andexpiration

the inferior region of the brainstem• Contains tracts running to and from the spinal cord, including the deccusation of pyramids• Cardiovascular center – nuclei regulating heart rate and blood pressure• Respiratory centers – nuclei regulating rate and depth of breathing• Other centers – nuclei regulating vomiting, sneezing, hiccups, and coughing

Cerebellum – second largest brain region (11% of mass) sitting beneath the occipital lobe•Divided into 2 hemispheres•Outer cortex of gray matter and inner branching white matter called the Arbor Vitae•Provides the coordination and fine tuning for precise, controlled muscle movements•Alcohol impairs this region, affecting ones gait, posture, and balance

a ‘functional system’ of the brain, including structures of the cerebrum and diencephalon, that regulates emotions.

-Hippocampus - forms memories

-Amygdala - processes feelings of fear, happiness, & sadness

-Includes olfactory structures assoc. smells w/ memories & emotions

A ‘functional system’ of the brain, including structures of themidbrain and brainstem, that regulates alertness and consciousness.•Includes the Reticular Activating System (RAS) which uses sensory stimuli to wake us from sleep

three layers of connective tissue membrane surrounding the brain and spinal cord

1.Covering and protecting CNS structures, esp. preventing movement2.Division of skull and brain into major regions3.Enclosing cerebrospinal fluid – providing buoyancy4.Enclosing blood – acting like veins

1.Dura mater2. Arachnoid mater3. Pia mater

thickest, outermost membrane• Dural septum – region of dura mater folding between major brainregions• Dural sinus – space created by dura mater that encloses blood(acting like a vein)

middle membrane• Subarachnoid space – deep to the arachnoid mater, enclosingcerebrospinal fluid (CSF)

innermost layer that clings to outer brain surface

CNS structures producing and enclosing cerebrospinal fluid(CSF)

hollow spaces in the brain filled with CSF, continuous with central canal of spinal cord and subarachnoid space

plasma-derived fluid that circulates through the ventricles and subarachnoid space (constantly replenished). Provides nourishmentto CNS tissues and buoyancy for the CNS structures.

structures in ventricles that produce the CSF

projections of arachnoid mater into dural sinuses, recycles CSF back into blood

buildup of CSF when drainage is blocked

brain capillaries are the least permeable in the body

region of CNS enclosed within the vertebral column

white matter tracts carry impulses to and from the brain. Internal graymatter performs nervous integration.

cone-shaped region at inferior end of spinal cord (near L1 vert.)

“horse tail” – bundle of spinal roots inferior to the end of the spinal cord

a sampling of CSF from the subarachnoid space.

• Surrounded by all three layers of meninges• Outer white matter surrounds inner gray matter• Spinal nerves branch laterally at each intervertebral space

divided into posterior, anterior, and lateral white columns

divided into dorsal, ventral, and lateral horns

hollow passage in SC for circulation of CSF

anterior branch of spinal cord containing motor fibers

posterior branch of spinal cord containing sensory fibers

enlargement containing somas of sensory neurons

fusion of dorsal and ventral roots, containing sensory and motor fibers