LAB 4 Exam Review

Central Nervous System (CNS)

brain and spinal cord, which are enclosed and protected by the cranium and vertebral column

Peripheral Nervous System (PNS)

nerves and ganglia

nerve

a bundle of nerve fibers (axons) wrapped in fibrous connective tissue

ganglion

knot-like swelling in a nerve where the cell bodies of neurons are concentrated

sensory division

What is the afferent division of the PNS?

motor division

What is the efferent division of the PNS?

The sensory division

carries signals from receptors (sense organs and simple sensory nerve endings) to the CNS

somatic sensory division

carries signals from receptors in the skin, muscles, bones, and joints

visceral sensory division

carries signals mainly from the viscera of the thoracic and abdominal cavities, such as the heart, lungs, stomach, and urinary bladder

The motor division

carries signals from the CNS to gland and muscle cells (effectors) that carry out the body's responses

somatic motor division

carries signals to the skeletal muscles

muscle contraction

voluntary control

somatic reflexes

involuntary control

visceral motor division (autonomic nervous system, ANS)

carries signals to glands, cardiac muscle, and smooth muscle --> visceral reflexes (unconscious)

sympathtic division

tends to arouse the body for action

parasympathetic division

tends to have a calming effect

epineurium

surrounds the entire nerve

Perineurium

surrounds each fascicle

Endoneurium

surrounds each nerve fiber

anterograde transport

movement away from the soma down the axon

retrograde transport

movement up the axon toward the soma

cerebrospinal fluid (CSF)

clear, colorless liquid that fills the ventricles and canals of the CNS and bathes its external surface

oligodendrocytes (CNS)

insulates the nerve fiber from the extracellular fluid (myelin sheath)

ependymal cells (CNS)

resemble a cuboidal epithelium lining the internal cavities of the brain and spinal cord

what does ependymal cells produce?

cerebrospinal fluid

Microglia (CNS)

are small macrophages that develop from white blood cells called monocytes

Astrocytes (CNS)

are the most abundant and constitute over 90% of the tissue in some areas of the brain

astrocytes

What neuroglia forms a supportive framework and the blood-brain barriers

scar tissue

Astrocytes form ----- and fill space formerly occupied by damaged neurons (astrocytosis or sclerosis)

Schwann cells (PNS)

also knowns as neurilemmocytes, envelop nerve fibers of the PNS

myelin

Schwann cells produce ---- similar to the one produced by oligodendrocytes in the CNS

schwann cells

What neuroglia assist in the regeneration of damaged fibers

Satellite cells (PNS)

surrounds the neurosomas in ganglia of the PNS

electrical insulation

Satellite cells provide ___ ____ around the soma

satellite cells

what neuroglia regulate the chemical environment of the neurons

myelin sheath

an insulating layer around a nerve fiber that accelerates the impulse

Oligodendrogytes (CNS) and Schwann cells (PNS)

what makes myelin

20% protein and 80% lipid

Components of the myelin sheath

The cerebrum

- is 83% if the brains volume

corpus callosum

the hemispheres are connected by a thick bundle of nerve fibers called

thalamus

- each side of the brain has this

thalamic nuclei

- nearly all input to the cerebrum passes by way of synapses in the

hypothalamus

- forms the floor and part of the walls of the 3rd ventricle

Epithalamus

very small mass of tissue composed mainly of the pineal gland and habenula (a relay from the limbic system to the midbrain) and a thin rood over the third ventricle

cerebellum

occupies the posterior cranial fossa inferior to the cerebrum, separated from it y the transverse cerebral fissure

vermis

the cerebellum consists of the right and left cerebellar hemispheres connected by a narrow bridge called the

Purkinje cell

the most distinctive neuron in the cerebellum is the

pituitary gland

endocrine gland at the base of the brain

pineal gland

secretes melatonin

midbrain, pons, medulla oblongata

components of the brainstem

foramen magnum

the brainstem ends at the ___ ____and the CNS continues below this as the spinal cord

medulla oblongata

- begins at the foramen magnum of the skull and ends at a groove between the medulla and pons

pons

- measures about 2.5 cm long, appears as a broad anterior bulge rostral to the medulla

longitudinal fissure

between the hemispheres

lateral fissure

between the parietal and temporal lobe

transverse fissure

between the occipital lobe and the cerebellum

gyrus (gyri)

ridges

sulcus (sulci)

depression or groove in the surface of the cerebral cortex; fissure

duramater

- consists of two layers - an outer periosteal layer equivalent to the periosteum of the cranial bones, and an inner meningeal layer

archnoid mater

transparent membrane over the brain surface

pia mater

very thin, that closely follows all the contours of the brain, even dipping into the sulci (not visible without a microscope)

lateral ventricles

form an arc in each cerebral hemisphere

third ventricle

each lateral ventricle is connected to this, inferior to the corpus collosum

fourth ventricle

passes down the core of the midbrain and leads to the, between the pons and cerebellum

spinal cord

- begins at foramen magnum and ends at L1-L2

cervical enlargement

gives rise to nerves of the upper limbs

lumbar enlargement

the issues nerves to the pelvic region and lower limbs

white matter

- consists of bundles of axons

gray matter

- central core of this looks somewhat butterfly of H shaped in cross section

31 pairs of spinal nerves

How many pairs of spinal nerves are there?

8, 12, 5, 5, 1

31 pairs

medullary cone (conus medullaris)

bundle of nerve roots that occupy the vertebral canal from L2 to S5

cauda equina

innervates the pelvic organs and lower limbs

C1- C5

- Cervical Plexus

C5-T1

brachial plexus

T12-L5

lumbar plexus

L4-S5

Sacral plexus

S4-Co1

coccygeal plexus

no plexus, has intercostal nerves instead

Thoracic region plexus

olfactory nerve (I)

- sense of smell

Optic Nerve (II)

- Begins at the retina of the eyes

Oculomotor Never (III)

Trigeminal (V)

Mainly sensory (sensation of the fact)

Facial Nerve (VII)

sensory component: sensation from the anterior 2/3 of the tongue

vestibulocochlear (VIII)

vestibular branch: detect movements that are linear and angular (turning)

Glossopharyngeal (IX)

Sensory: neuros for taste to posterior 1/3 of tongue, sensory neurons of pharynx and eardrum

Vagus Nerve (X)

Sensory: pharynx, external acoustic meatus, diaphragm ,and internal organs of the thoracic and abdominopelvic cavities

Accessory Nerve (XI)

entirely motor and innervates the trapezius and sternocleidomastoid muscles

Hypoglossal Nerve (XII)

entirely motor and innervates the muscles that move the tongue

receptor, sensory neuron, integration center, motor neuron, effector

arc reflex steps

Cataracts

*clouding of the lens*

glaucoma

*elevated pressure*

- consist of a pair of cerebral hemispheres

- a deep median groove, the longitudinal fissure, separates the right and left hemispheres from each other

- plays a key role in motor control

- signals from the cerebellum to the cerebrum

- is involved in the memory and emotional functions of the limbic system (temporal and frontal lobes)

- controls taste, smell, hearing, equilibrium, vision, touch, pain, pressure, heat, and cold

- from the optic chiasm to the mamillary bodies

- is the major control center of the endocrine and autonomic nervous systems ----> homeostatic regulation