How can we help?

You can also find more resources in our Help Center.

171 terms

hap 10-11 nervous system

The branch of medical science that deals with the nervous system
The two Main divisions of the nervous system
CNS -The Central Nervous System
- consists of the brain and spinal cord - where sensory info is analyzed - generation of thoughts / emotions / impulses for muscle contraction / gland secretion
PNS - The Peripheral Nervous System
- cranial & spinal nerves
- carry impulses to / from CNS
Afferent neurons
transmit impulses toward CNS
Efferent neurons
transmit impulses away from CNS
E for exit
PNS is divided into 2divisions
Somatic Nervous System and the Autonomic Nervous System
Somatic Nervous System SNS
-sensory neurons for special sense receptors and
coetaneous (skin) receptors to CNS
(vision, taste, touch, pain, - voluntary - we are conscious of these)
- motor neurons transmit impulses to skeletal muscle
Autonomic (Automatic) Nervous System ANS
"Auto pilot" sensory neuron from things not aware of - involuntary
- sensor neurons from visceral receptors
- motor neurons to smooth muscle, cardiac, muscles ..and glands (body is aware, you are not ex: digestion of food)
Sympathetic Branch of PNS
expenditure of energy "fight or flight"
everything required to fight
or run for your life
kicks in automatically
Para-sympathetic Branch of PNS
conservation of energy
"feed or breed" all blood goes to digestion / no blood for breeding
Two Main Cell Types of the Nervous System
1. Neurons
2. Neuroglia
helper cells to neurons -
different types and functions
usually multiple dendrites
- Afferent process - transmits impulses toward cell body
"star shaped" (astro-star)(cyte-cell)
metabolism of neurotransmitters-"like acytlcoline"
help to form blood brain barrier in CNS
Produce myelin sheath CNS
Physically support neurons by a gel matrix that they secrete "think of fruit suspended in a Jell-O mold"
myelin sheath
a layer of lipids (fats) & proteins
that surround the axons of some neurons
Derived from (monocytes- a specific type of white blood cell)
"phagocytic"- it eats bacteria & cellular debris CNS
Ependymal Cells
line ventricles of brain and central canal of the spinal chord CNS
Schwann Cells
- produce myelin sheaths in the PNS
Satellite Cells
- support neurons in PNS Ganglia
- a collection of nerve cell bodies found in the PNS
- myelin sheath is a layer of lipids and proteins that surround the axons of some neurons
- insulates the axon - speeds conduction time by arching between the Nodes of Ranvier
- connection between 2 neurons or between a neuron and an effector
Nerve Fiber
- any neuronal process
- usually an axon
bundle of nerve fibers (usually axons) located In the Peripheral Nervous System (PNS)
neuromuscular junction
types of synapses where the effector is "muscle"
neuroglandular junction
types of synapses where the effector is a gland
2 specific types of synapses
1. neuromuscular junction
2. neuroglandular junction
bundle of nerve fibers located in the (CNS)
Multipolar Neurons
- many dendrites - a single axon
- brain / spinal cord (mostly these)
Bipolar Neurons
- single dendrite - single axon
- usually assoc with special senses Rods / black & white
Cones / 3 types / red, blue, green
Unipolar Neurons
- "receptors" - single process
Afferent Neurons
- transmit toward CNS
Efferent Neurons
- transmit (exit) away from CNS
Association Neurons
-also called "Interneurons"
- relay impulses from one neuron to another- 90% of all neurons are Association Neurons
- Communication by neurons
2 basic properties of plasma membranes:
Resting Membrane Potential "RMP"
and Ion Channels
Resting Membrane Potential "RMP"
- an electrical charge / due to a separation of ions on each side of the neurons plasma membrane
-is maintained in part by ion pumps (active transport)
( - ) negatively charged ions inside neurons plasma membrane
( + ) positively charged ions outside neurons plasma membrane
Leakage Channel
- (one way doors) or Channels - always open in the
direction of RPM
Gated Channels
-Channels open or closed based on specific stimulus
the 4 types of gated channels:
Very Chilly Morning Light (picture frost on the gate at sunrise)
voltage, chemically, mechanically, light
Voltage Gated Channel
Channel opens to a response to a change in RMP
Chemically Gated Channel
Channel open or closed based upon a specific chemical (neurotransmitter)
Mechanically Gated Channel
Channel opens in response to pressure or vibration
Light Gated Channel
Channel opens in response to a specific wavelength (or color) of light
- open door in plasma membrane> in which channels open >
cations - / anions +
- has momentum
Move equalibrium of depolarization
-70mv > 0 > 30mv before moving back to -70mv
-Gated channels get closed
(RMP is restored)
-Use leakage channels 1st then ion pumps.
refractory period
The period of time before repolarization.
Saltatory Conduction
the arcing (or jumping) of action potentials along myelinated axons from one node of Ranvier to the next
speed of conduction along an axon is dependent upon the _______ of the fiber.
The "size" of the fiber.
The larger the fiber the faster the speed.
Stimulus intensity is a function of _____________.
frequency--all impulses are equal in strength, it is the frequency of impulses that create intensity
Name 2 Types of Synapses
Excitatory Postsynaptic Potential - (EPSP)
Inhibitory Postsynaptic Potential - (IPSP)
Excitatory Postsynaptic Potential - (EPSP)
- causes partial postsynaptic polarization of the postsynaptic membrane.
-with each EPSP the postsynaptic membrane is pushed closer to the threshold (summation)
Inhibitory Postsynaptic Potential - (IPSP)
hyperpolarization- the opposite of depolarization.
- at about 6 months of age neurons no longer undergo mitosis ( no new cells are formed )
- a substance that mimics a neurotransmitter example: Caffeine
- a substance that blocks a neurotransmitter example: Novocain
Spinal Cord
- location within the vertebral canal of the vertebral column
- covered by a layer of protective tissue called meninges
Regions/ Layers of Meninges
Epidural Space, Dura mater, Subdural Space, Arachnoid mater, Subarachnoid Space, Pia mater
Dura mater
(dura-tough / mater-mother)
Outermost layer of meninges
Subdural Space
region between duramater and arachnoid-filled with interstitial fluid
Arachnoid mater
(spider legged) - Middle layer- arachnoid villi
Subarachnoid Space
between arachnoid and piamater- filled with cerebrospinal fluid
Pia mater
(pia-little / mater-mother)- Innermost thin membrane on surface of spinal cord
Epidural Space
- filled with fat & other connective tissue outside the duramater
- fast automatic responses - involuntary
- route followed by impulses from origin to destination
Reflex Arc
- Simplest pathway
5 Functional Components of the Reflex Arc
1 Receptor, 2 sensory neuron, 3 integrating center 4 motor neuron 5 effector
- (Unipolar Neuron) - responds to stimulus via EPSPS
Sensory Neuron
- relays impulses from receptor to spinal column
Integrating Center
- located within the CNS
- consists of 1 or more Association Neurons- may relay
impulses to cerebral cortex
Motor Neuron
- "Efferent Neuron" that sends impulse to body part that will respond
- body part that responds
if effector is skeletal muscle
Somatic Reflex -"since you are aware of it" (voluntary muscle)
if effector is visceral
Visceral Reflex -"Cardiac, stomach or gland"
Spinal Nerves-connect to CNS & PNS in 31 pairs
name & # in each set
8 pairs Cervical
12 pairs Thoracic
5 pairs Lumbar
5 pairs Sacral
1 pair Coccyseal
Spinal Nerves typically have 2 points of attachment to the spinal cord called roots; name them:
Anterior Root
Posterior Root
Spinal Nerves are covered by 3 types of protective C.T.- name them:
Epineurium, Perineurium, Endoneurium
protective c.t. - covers whole spinal nerve
protective c.t. -covers bundles of spinal nerve fibers (axons)
protective c.t. - covers individual spinal nerve fibers
receptor is # ______
Effector is #
sensory neuron is #
2 carries impulse from receptor into cell body
Interneuron is #
6 between the sensory neuron and the motor neuron
cell body of sensory neuron #
motor neuron #
4 carries impulse from interneuron out to effector (muscle or gland)
central canal #
white matter #
dorsal area # (not 7)
spinal cord (#7)
gray matter #
ventral #
central canal #
posterior median sulcus #
Anterior funiculus #
Gray commissure #
portion of spinal nerve #
Anterior median fissure #
Posterior funiculus #
dorsal root of spinal nerve #
gray matter #
anterior horn #
lateral funiculus
dorsal root ganglion #
ventral root of spinal nerve
white matter
Posterior horn
Bipolar Neuron
has a single dendrite and a single axon
multipolar neuron
has multiple dendrites and a single axon
unipolar neuron
has a single axon
Schwann cells in PNS and oligodendrocytes in CNS
the neuroglial cells responsible for forming myelin sheaths around axons
The brain stem consists of the
The brain stem
connects the spinal cord to the remainder of the brain
damage to the brain stem
is usually fatal.
the brain stem controls many
essiental functions
autonomic and somatic
the divisions of the periferal nervous system
the parasympathetic branch of the nervous system
deals with activities that are involved in the conservation of energy.
medulla and pons
the 2 parts of the brain involved in controlling respiration
voltage gated channels open in response
to a change in RMP.
the largest portion of the diencephalon
the part of the brain located between the medulla and the mesencephalon
cranial and spinal nerves
what does the periferal nervous systen consist of?
Most of the neurons in the CNS and most motor neurons are -----polar neurons
reflexes are fast _______responses
chloroid plexuses form
cerebrospinal fluid
To seperate the brainstem from the rest of the brain, I would need to make a cut
above the mesencephalon(top of brain stem) and below the diancephalon(inferior part of the brain)
neuroglia also serves as
the major supporting tissue in the cns
After plasma goes through the endothelio cells a second filtration of plasma by neuroglia results in
the formation of the blood-brain barrier
refractory period
the period of time during which a neuron cannot generate another action potential
postsynaptic membrane
in an excitatory postsyaptic potential the _________ becomes partially depolarized
mechanically gated
a specific type gated ion channel thar responds to pressure or vibrations.
In RMP ther is a build up of ______
"inside" the plasma membrane.
are located in the medulla
centers to regulate reflexes such as breathing, swallowing, vomiting, coughing, and sneezing
Symptoms of irregular body temperature, intense thirst, lack of appetite, might indicate a disfunction of what part of the brain
bundle of nerve fibers
lobes of the cerebrum
occipital, temporal, frontal,parietal
Afferent neurons send impulses
toward the CNS
Leakage channels
ion channels that are always open
After passing through the intervetebral foramem spinal nerves branch. These branches are called _______________.
3 types of Rami
1. Dorsal Ramus
2. Ventral Ramus
3. Meningeal Branch
Dorsal Ramus
- controls dorsal (back) structures
Ventral Ramus
-controls ventral (front) structures
Meningeal Branch
- re-enters the intervetebral canal and serves the vertebra & the meninges
- form networks, or "Plexuses",
Ventra rami plexuses
1. Cervical Plexus., Cindy .,
2. Brachial Plexus. , Brady.,
3. Lumbar Plexus., Loves,.
4. Sacral Plexus., Singing...,
Cranial Meninges
Brain is covered, / protected, by _______..,(Same setup. as spinal meninges Dura mater,
Arachnoid mater,. Pia mater)
Cerebrospinal Fluid (C.S.F.).
,- "double -filtered plasma"
that is filtered by endothelial cells. and neuroglia cells ..(the second filtration causes the blood-brain barrier.)
circulates through ventricles of the brain to the subarachnoid space....
.- provides mechanical shock protection for the brain....
.- acts as blood of CNS....
.- provides nutrients...
.- removes wastes....
Chloroid Plexuses
(networks of Ependymal Cells which produce CSF are called____________. This production of CFS creates a positive pressure
arachnoid villi
CSF flows from ventricles through a series of aperatures, aquaducts and foramen to the subarachnoid space where it is absorbed by the________ which creates a negative pressure.
list in asending order the various parts of the brain
5...Diencephalon 4....Mid-Brain-(Mesencephalon)
3...Reticular Formation 2 ...Pons 1... Medula Oblongata
Thalamus and the Hypothalamus
2 parts of the Diencephalon
largest part of the brain
the cerebrum is separated into lobes by fissures called________.
Frontal, Parietal, Temporal, Occipital
the lobes of the Cerebrum are named for skull bones directly above them, name them:
Cerebral Cortex
outer 2-4 mm
- seat of intelligence
- spoken or written language, create,
compose, memory, calculate
- gray matter
Basal Ganglia & Limbic System
2 Components of Cerebrum
Basal Ganglia
coordinate gross muscle movements & coordination
helps regulate muscle tone (Tonus)
Limbic System
- controls emotional aspects of behavior related to survival ex: fear, sorrow, sex, docility, rage,
aggression, affection
Electroencephalogram (EEG
-Neurons of brain produce detectable electric activity
An instrament used to detect electrical brain activity is called________________.
Alpha Waves
- present when awake ,
absent while sleeping
Beta Waves
- present when nervous system is active ("thinking")
Theta Waves
- emotional, stress, fear, crying
Delta Waves
- present while in deep sleep
"in infants" also while awake in 1st yr
Left hemisphere- (Men are more left hemisphere)
- controls right side of the body
- also in control of calculations,
reasoning, spoken or written language
Right hemisphere
- controls left side of the body
- musical / artistic, awareness,
Insight, & imagination
- - 2nd Largest portion of the brain
- shaped like a cauliflower
-controls skeletal musclemovements
used in skilled activities, coordination,
posture, & balance