BIOL 319 Lab 9 Neurology

cerebrum

largest region of the brain and is divided into right and left cerebral hemispheres (not entirely equal in function) by the longitudinal fissure

longitudinal fissure

deep groove dividing the right and left cerebral hemispheres

lateralization

specialization of cortical functions between the left and right cerebral hemispheres

gyrus

a fold in the cerebral cortex

sulcus

a shallow groove

corpus callosum

white matter that connects the cerebral hemispheres

gray matter of the cerebral cortex

forms the outer convoluted surface of the cerebral hemispheres and the foliated surface of the cerebellum

white matter

lies deep to the cerebral and cerebellar cortices

cortical gray matter

made of multipolar neuron cell bodies and attendant dendrites

pyramidal cells

many of the multipolar neurons of the cortex are classified as this due to the pyramid or triangle shape of their cell bodies

the cerebral cortex can be divided in 5 basic layers

1. molecular layer

2. outer granular layer

3. outer pyramidal cell layer

4. inner granular layer

5. inner pyramidal and polymorphic layer

molecular layer of the cerebral cortex

contains mainly dendrites synapsing with cortical neuron axons

outer granular layer of the cerebral cortex

mostly made up of stellate cells, axons, and dendrites

outer pyramidal cell layer of the cerebral cortex

mostly made up of pyramidal cells that increase in size as you move deeper into the layer

inner granular layer of the cerebral cortex

mostly made of densely packed stellate cells

inner pyramidal and polymorphic layer of the cerebral cortex

mostly composed of large pyramidal cells in the more superficial portion of the layer and a wide variety of cell morphologies in the deepest parts of the layer

diencephalon consists of 3 paired structures

thalamus, hypothalamus, epithalamus

thalamus

a relay station for incoming information (like sensory or integration information) thats destined for higher brain areas like the cerebral cortex

hypothalamus

-the autonomic control center

-center for emotional response

-body temperature regulation

-regulation of food intake

-regulation of water balance and thirst

-regulation of sleep-wake cycles

-control of endocrine system functioning

mammillary bodies

relay stations in the olfactory pathways

infundibulum

a stalk of hypothalamic tissue that connects to the pituitary gland

epithalamus

contains the pineal gland that secretes the hormone melatonin that helps regulate the sleep-wake cycle

pineal gland (or pineal body)

-located in the epithalamus which is the superior-most part of the diencephalon

-under the control of a complex feedback loop with the "suprachiasmatic nucleus (SCN)" of the hypothalamus

-secretes the hormone melatonin that regulates circadian rhythms

melatonin

a hormone that regulates circadian rhythms; an indoleamine derived from tryptophan

cerebellum

-located dorsal to the pons and medulla oblongata

-primarily involved in the coordination of somatic motor function, primarily skeletal muscle contractions

-learned muscle patterns are stored and processed in the cerebellum

-is partitioned into cortical layers: gray matter (divided into 3 layers: molecular layer, intermediate layer, and granular layer) and white matter

molecular layer of the gray matter in the cerebellum

composed largely of unmyelinated fibers and scattered basket cells and stellate cells

intermediate layer of the gray matter in the cerebellum

laden with Purkinje cells

granular layer of the gray matter in the cerebellum

deepest layer; rich in granule cells

brain stem

made up of the medulla oblongata, pons, and midbrain

midbrain

-located between the diencephalon and pons

-associated with inhibiting inappropriate muscle movements and dopamine signals to ease that inhibition to allow for smooth movements

pons

-located between the midbrain and medulla oblongata

-chiefly composed of conduction tracts between higher brain centers and the spinal cord or between the motor cortex and cerebellum

medulla oblongata

most inferior part of the brain stem; has some control over the cardiovascular and respiratory systems

anterior median fissure

marks the dividing line between the mirrored right and left halves of the spinal cord

contralateral

opposite side

ipsilateral

same side

cranial nerve I

-olfactory nerve

-sensory

-tiny sensory nerves of smell which run from the nasal mucosa to the olfactory bulbs

cranial nerve II

-optic nerve

-sensory

-sensory nerve of vision that develops as an outgrowth of the brain, it is really a brain tract

cranial nerve III

-oculomotor nerve

-motor

-this nerve's name means "eye mover" because it supplies four of the six extrinsic muscles (inferior oblique, medial rectus, inferior rectus, superior rectus) that move the eyeball in the orbit

cranial nerve IV

-trochlear nerve

-motor

-this nerve's name means "pulley" and it innervates the superior oblique, and extrinsic eye muscle that loops through a pulley-shaped ligament in the orbit (trochlea)

cranial nerve V

-trigeminal nerve

-sensory and motor

-3 branches spring from this; largest of the cranial nerves; supplies sensory fibers to the face and motor fibers to the chewing muscles

cranial nerve VI

-abducens nerve

-motor

-controls the lateral rectus

cranial nerve VII

-facial nerve

-sensory and motor

-large nerve that innervates muscles of facial expression (among other things)

cranial nerve VIII

-vestibulocochlear nerve

-sensory

-for hearing and balance

cranial nerve IX

-glossopharyngeal nerve

-sensory and motor

-means "tongue and pharynx", revealing the structures it innervates; its primarily sensory to the throat

cranial nerve X

-vagus nerve

-sensory and motor

-the only cranial nerve to extend beyond the head and neck to supply motor and sensory fibers to the visceral body organs of the throat and abdomen

cranial nerve XI

-spinal accessory nerve

-motor

-primarily motor and supplies the trapezius and sternocleidomastoid muscles

cranial nerve XII

-hypoglossal nerve

-motor

-means "under the tongue" and runs inferior to the tongue and innervates muscles of the tongue

meissner's corpuscles

-function as light pressure receptors of the dermis

-located within the dermal papillae just below the epidermal/dermal border

epineurium

surrounds the entire nerve

perineurium

surrounds each fascicle

endoneurium

surrounds each individual axon

myelin sheath

encase axons

schwann cells

myelin sheaths of the PNS that are derived from glial cells

nodes of Ranvier

unmyelinated gaps between schwann cells

saltatory

jumping