Nervous System

CNS

Central Nervous System, consisting of the brain and spinal cord.

PNS

Peripheral Nervous System, includes cranial and spinal nerves.

12

number of cranial nerves

31

number of pairs of spinal nerves

fight or flight (cardiac muscles, smooth muscles, and glands)

what does the sympathetic division dictate

conserve energy, promotes “housekeeping” functions during rest, resting and digesting,

Parasympathetic division does what

muscles, glands, and adipose

what structures have motor nerve fibers

Involuntary muscle (adipose, certain endocrine glands)

Enteric nervous system controls what

Meninges

Connective tissue membranes surrounding the brain and spinal cord.

Cranial Nerves

12 paired sets of PNS nerves emerging from the brain stem.

Spinal Nerves

31 pairs of mixed nerves that emerge from the spinal cord.

Mnemonic for 12 cranial nerves

Some

say

marry

money

but

my

brother

says

big

brains

make

more

Somatic Division

Controls voluntary muscles (skeletal muscles).

Autonomic Division

Controls involuntary muscles, glands, and adipose tissue.

Parasympathetic

Subdivision of the ANS responsible for "rest and digest" functions.

Sympathetic

Subdivision of the ANS responsible for "fight or flight" responses.

Homeostasis

Regulation and control of bodily functions.

Sensory Input

Detection of environmental changes and stimuli.

Integration

Processing of information sent to the CNS by the PNS.

Control

Efferent output to effectors via PNS motor neurons.

Mental Activities

Functions such as thinking, learning, and memory, behavior.

Thermoreceptors

Receptors that detect changes in temperature.

Nociceptors

Free nerve endings-Receptors that detect potentially harmful stimuli, such as pain, itching.

Mechanoreceptors

Receptors that detect pressure, e.g., Pacinian corpuscles, Merkel discs.

Chemoreceptors

Receptors that detect chemical stimuli, e.g., taste cells.

Photoreceptors

Receptors that detect light, found in the retina.

Nerves

Bundles of axons in the nervous system.

Ganglia

Collections of neuron cell bodies in the PNS.

Plexuses

Networks of nerves dedicated to specific body areas.

Sensory Neurons

Unipolar neurons that detect stimuli and synapse with interneurons.

Motor Neurons

Multipolar neurons that synapse with effectors.

Interneurons

Association neurons that relay information between sensory and motor neurons.

Unipolar Neurons

Neurons with one cytoplasmic process; typically sensory neurons.

Bipolar Neurons

Neurons with two cytoplasmic processes; often found in special senses.

Multipolar Neurons

Neurons with multiple dendrites and one axon; typically motor neurons.

ANS

Autonomic Nervous System, controls involuntary bodily functions.

Reflex Arcs

Pathways that mediate reflex actions.

Efferent Neurons

Motor neurons that carry signals away from the CNS.

Effectors

Muscles, glands, and adipose tissues that respond to motor neuron signals.

Neuroglial Cells

Supportive and protective non-conductive cells in the nervous system.

Oligodendrocytes

CNS cells that produce the myelin sheath.

Astrocytes

Abundant CNS glial cells that connect neurons to blood vessels.

Microglial Cells

Phagocytic cells in the CNS that protect against invaders.

Ependymal Cells

Glial cells that help produce and circulate cerebrospinal fluid (CSF).

Schwann Cells

produce myelin sheath of white matter axons of PNS neurons

Satellite cells

protective and supportive glial cells. Very abundant around cell bodies of sensory neurons in PNS ganglia

Myelin Sheath

Insulative covering around axons that speeds up nerve impulse conduction.

CNS

In what system do oligodendrocytes form the myelin sheath

PNS

In what system do Schwaan cells form the myelin sheath

Nodes of Ranvier

Gaps in the myelin sheath that facilitate faster nerve impulse conduction.

Saltatory Conduction

To skip or jump- nerve impulses that jump because of nodes of ranvier

continuous conduction

impulses on axons that are non-myelinated- no jumping and eventually die off on long axons

Cranial Nerves

Nerves that emerge directly from the brain, some sensory, some motor.

mnemonic for names of cranial nerve

Oh, Oh, oh, to touch and feel a very glossy Volkswagen…ah heaven!

Olfactory (I) nerve

smell-sensory

Optic (II) nerve

vision-sensory

Oculomotor (III) nerve

mvmnt of eyeballs and eyelids-motor

Trochlear (IV) nerve

eyeball mvmnt-motor (somatic)

Trigeminal (V) nerve

3 branches- innervation of face and mouth- largest cranial nerve- ophthalmic, maxillary, and mandibular- both

Abducens (VI) nerve

lateral mvmnt of eyeballs-motor

Facial (VII) nerve

5 braches- temporal, zygomatic, buccal, mandibular, cervical-innervation of face and neck-both

Auditory / Vestibulocochlear (VIII) nerve

two branches: auditory (hearing)
and vestibular (equilibrium)-Sensory

Glossopharyngeal (IX) nerve

innervation of the tongue and throat- both

Vagus (X) nerve

longest of the cranial nerves – extends into the thoracic and part of the abdominal regions-Both

-Senses changes in blood chemistry and other metabolic conditions
related to sympathetic and parasympathetic conditions
-Motor output to the heart, mostly parasympathetically to slow heart
rate

Slow/stop

overstimulation of vagus nerve can cause heart to do what

Accessory (spinal) (XI) nerve

located more posterior than the rest of the of
the cranial nerves, very close to the beginning of the of the spinal cord- Motor-functions in innervating the sternocleidomastoid and
trapezius muscles

Hypoglossal (XII) nerve

(“under the tongue”) innervation of the tongue-motor

Brainstem

Connects the spinal cord to the brain and integrates survival reflexes.

Cerebellum

Part of the brain responsible for balance and coordination.

Midbrain

produces dopamine and important for fine motor skills

Pons

relay center between ANS and PNS

Diencephalon

Contains the thalamus, epithalamus, and hypothalamus( regulates ANS functions, endocrine system, temp. reg., and thirst center)

Cerebrum

Responsible for conscious thought and control of body functions.

Ventricles

Cavities in the brain that contain cerebrospinal fluid (CSF).

Choroid plexus

modified capillaries in lateral ventricles of brain. Main source of spinal fluid.

Serves as barrier separating blood from CSF

3rd ventricle

. Cerebral aqueduct – delivers cerebrospinal fld (CSF) to the ventricles and
spinal cord central canal

By midbrain

4th ventricle

Central canal of the spinal cord – CSF – interstitial fluid – “outside” of and
in between cells

Functions of Medulla Obligata

respiratory centers

Cardio center

cont. w spinal cord

ascending and descending tracts of CNS- myelinated (white matter) -some gray matter

blood vessel diameter

swallowing

hiccups, coughing, sneezing

Functions of pons

monitor blood chemistry, blood pressure, O2, and CO2.