functions of the nervous system
receive sensory input, integrate info, control muscles, maintain homeostasis, establish and maintain mental activity.
what are the two divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS)
What are the 2 functional subdivisions of the PNS?
sensory division or afferent division (toward) and motor division efferent (away)
how is the motor division divided
somatic nervous system, autonomic nervous system (ANS) and enteric nervous system (ENS)
central nervous system (cns)
includes the brain and spinal cord
peripheral nervous system (pns)
nervous tissue outside of the cns (nerves and ganglia)
detects enviromental stimuls (internal or external) sends that info to cns for response, reaction or reflexes
autonomics nervous system
includes nerves that control structures automatically or involuntary.
somatic nervous system
includes nerves that voluntarily (conscious) control skeletal muscle fibers
an electrically charged cell that connects with other neurons to form networks in the CNS & PNS
short,branching cytoplasmic extensions of the neuron body
long cell process extending from the neuron cell body.
area where the axon leaves the neuron cell body
what is it called when an axon branches?
it forms a collateral axon
neural tissue which supports, protects and insulates neurons
major supporting tissue in the CNS
blood brain barrier
blood vessels that selectively let certain substances enter the brain tissue and keep other substances out
cells that line fluid filled cavities in the CNS and spinal cord. assist in producing and circulating CSF
protects the CNS by engulfing invading microbes
Involved in production of insulating covering-myelin sheaths around axons in CNS. They CANNOT regenerate new nerve fiber
forms myelin sheaths around axons in PNS. They can regenerate nerve fiber.
structural support of neurons. Exchanges between capillaries and neurons
substance released at axon terminal end
neurotransmitter found in neuromuscular junction of skeletal muscle.
rest in indentations of the oligodendrocytes in the CNS and schwann cells in the PNS
when acetylcholine binds to sodium membrane receptors & opens membrane channels, the sodium rushes into the cell & causes cell to become depolarized. A nerve impulse is a wave of ATP
resting membrane potential
a resting unstimulated neuron has a greater concentration of sodium outside the cell than in.
what is the BRAINSTEM made up of?
medulla oblongata, pons & midbrain.
action of the medulla oblongata
helps regulate heart rate & breathing.
Why would a brainstem stroke be so deadly?
all nerve impulses from brain that go to body must go thru brainstem. It also controls breathing, BP, & heart rate. you could become hemiplegic, paralyzed, or comatose. Death.
the posterior part of the forebrain, made up of the thalmus, epithalamus and hypothalamus.
control of body temperature, hunger and thirst.
cerebellum is involved in balance, muscle tone and fine motor movement.
is the largest part of the brain consisting of 2 hemispheres & including the cortex & nerve tracks. Made up of 4 lobes: frontal, parietal, occipital & temporal
gray outer matter region of the cerebral hemispheres. It enables us to communicate, perceive, remember, all qualities having to do with consciousness
what are the grooves & ridges of the brain called?
Gyrus, Sulcus, Fissure
outward elevated ridge of tissue
a shallow groove
a deep groove or cleft
how many cranial nerves?
olfactory bulb nerves
optic nerve controls
move face and teeth muscles to chew (s) sensory (m) muscle
hearing and balance (s)
cranial nerve extend beyond head and neck
inflammation of the 7th (VII) cranial nerve, or facial nerve
what childhood sickness lies dormant in the dorsal root ganglia?
what 2 sicknesses does herpes zoster cause?
chicken pox and shingles
what common disease sets up in the transgeminal nerve?
herpes simplex I
what disease hides in the dorsal sacral nerve
herpes simplex II
can herpes simplex I become a STD?
How many pairs of spinal nerves are there?
31 pairs in 3 plexuses
stimulates the diaphragm-wind knocked out of you
stimulates muscles in posterior arm and forearm
stimulates 2 anterior forearm muscles and hand muscles, known as the funny bone
sciatic nerve runs through which hip muscle?
cerebrospinal fluid (CSF) is produced by what?
choroid plexuses of each of the 4 ventricles
pathway-choroid plexuses TO CSF from lateral ventricle flowing to the 3rd ventricle TO the cerebral aqueduct THEN to the 4th ventricle CSF exits the 4th ventricle through its walls & enters subarachnoid space then flows through Subarachnoid space TO arachnoid granulations in superior sagittal sinus, where it enters the venous circulation
the direction of CSF flow
what is meninges made of?
3 connective membranes: Dura Mater, Arachnoid Mater, Pia Mater
How are the 3 meninges membranes attached
dura mater: tightly attached to skull. Arachnoid mater: is a thin and wispy layer. Pia Mater: is attached to the surface of the brain.
sarcomeres shorten when muscles contract the actin & myosin filaments SLIDE past each other & myosin heads bind briefly to the actin (forming cross bridges) & swivel. when crossbridges are broken & actin and myosin return to their original positions and muscles relax
cell membranes that are wrapped around the axon many times with their cell membranes
impulses begin at the sensor
dendrites convey the impulses to where nucleus is
areas of CNS with myelin are called
neuron spaces between the myelin sheaths are called
nodes of ranvier
where white blood cells attack the myelin mistaking it for a similar virus
bundles of neurons, axons in the pns form
bundles of neurons in the cns form
they are the source of CNS cancers
posterior (dorsal) root ganglion
sensory cell bodies are located in the
a group of nerve cell bodies located in the pns
tiny non myelinated neurons found in the gray matter of the spinal cord
nerve impulse stops at a space that separates the sensory axon from the dendrites of the motor neuron
is the meeting between a neuron and an effector
is a structure that will put the nerve signal "into effect"
anterior (ventral) root
the motor neuron axon leaves the anterior spinal cord gray matter and joins the nerve
the response to impulse conduction over reflex arc is called
a sensory neuron alerts a motor neuron to tell the quadriceps to contract, or shorten this is called
puttin your finger on a stove implements another reflex arc called
self propagating wave of electrical disturbance that travels along the surface of a neuron's plasma membrane
action potentials, ATP
nerve impulses are also know as
if the traveling impulse encounters a section of membrane covered with myelin, it "jumps" the myelin and actually speeds up the conduction
neuron before the synapse is called
neuron after the synapse is called
presynaptic neurons axons terminate in bulges where chemicals are stored inside called
chemical inside the knobs are enclosed in sacs called
endorphins and inkephalins
are released at brain and spinal cord synapses in the pain conduction pathway
is the lowest part of the brain and includes in order above the spinal cord: the medulla, pons and midbrain
all three have an area that determines the alertness level of the brain