Chapter 8
8.1
8.2
8.3
8.4
kahoots ch 8. 1-3
The brain and spinal cord comprise the
central nervous system
the part of the peripheral nervous system that brings information to the central nervous system is the
afferent division
most neurons in the brain are
multipolar
the cytoplasmic extensions that, together with the cell body provide the main receptive surfaces for neurons are the
dendrites
the largest and most numerous of the glial cells in the central nervous system are the
astrocytes
the myelin sheaths that surround the axons of some of the neurons in the CNS are formed by
oligodendrocytes
small phagocutic cells that are especially obvious in damaged tissue in the CNS are the
microglia
Most neurons lack centrioles. this observation explains
Aggregations of ribosomes in neurons are referred to as
Nissl Bodies
Neurons that have one axon and one dendrite with the soma between them are called
bipolar
why these neurons cannot regenerate
The polarization of a nerve fiber refers to having the
potassium ions inside the cell and sodium outside the cell
saltatory conduction
is faster than conduction on an unmyelinated axon
Opening of sodium channels in the membrane of a neuon results in
Depolarization
When a neuron is at rest, which ion passes through its membrane most easily
potassium
The all or none principle states that
All stimuli great enough to bring the membrane to threshold will produce identical action potentials
8.4-8.6
Synaptic knobs occur at the ends of
dendrites
Neurotransmitters are released from the
synaptic terminals/knobs
which type of synapse dominates the nervous system
chemical
the ion needed to initiate the release of acetylcholine into the synaptic cleft is
calcium
Adrenergic synapses release the neurtransmitter
norepinephrine
which of the following lists the part of a reflex arc in the correct order
receptor, sensory neuron, interneuron, motor neuron, effector
Series of evens that occur at a typical cholinergic synapse
2,1,6,7,4,3,5
The specialized membranes that protect the spinal cord are termed
spinal meninges
Blood vessels sevicing the spinal cord are found in the
pia mater
The dural sinuses are located in the
dura mater
what contains a delicate network of collagen and elastin fibers through which cerebrospinal fluid circulates
subarachnoid space
Diffusion across the arachnoid villi returns excess CSF to
Venous circulation
The projection of gray matter toward the outer surface of the spinal cord are called
horns
Masses of myelinated nerve fibers appear
white
8.5-8.6
Axons crossing from one side of the spinal cord to the other within the gray matter are found in the
gray commissures
The white matter of the spinal cord contains
bundles of axons that share common origins destinations and functions
Enlargements of the spinal cord occur
in segments of the spinal cord that control the limbs
The entire spinal cord is divided into __ segments
31
The horns of the spinal cord contain
nerve cell bodies
The posterior horns of the spinal cord contain
sensory nuclei
Gray matter in the spinal cord is mostly
interneurons
If the dorsal roof of a spinal nerve is severed
incoming sensory information would be disrupted
Central nervous system = brain & spinal cord
A resting neurons cell membrane is said to be polarized = electrically charged
DEF: potential Difference = the difference in electrical charge between 2 points
K: high inside Na: High outside Cl: High outside
The RMP of a nerve cell is measured to be 70-MV or millivolts
More negative = Hyperpolarization Less negative = depolarization
Na+ channels results in paid depolarization
DEF Nerve impulse (NI) The popagation of action potentials
Refractory Period
The period following a NI when a threshold stimulus cannot produce another NI
All or Nothing Response
if a nerve cell responds at all, it repsonds completely
Summation - many subthreshold stimuli received one after another may allow threshold potential to be reached
Synapse
the junction between two neruons where a nerve impulse is transmitted
Most typical NT is Acetylcholine (ACh)
Chapter 8
8.5
8.6
8.7
8.8
Meniges
The membranes around the brain and spinal cord
Dura matter
outtermost membrane that is attached to the inner periosteum
Arachoid mater
middle layer
Pia
inner layer that clings to brain surface
Very thin
Thin-net like membrane
Tough white fibrous CT
Spinal cord
The space between the dura matter and the bone is called the Epidural Space
Secretion and Circulation of CSF
Specialized capillaries in chorid plexuses
Total volume in above spaces = 150 mL
Functions
mechanical protection
Chemical Protection
Length = about 17 inches
start = foramen magnum
Contains 31 segment (31 pairs of spinal nerves)
Cauch Equinn ( Horses tail)
Cross- sectional Anatomy of spinal cord
- Gray matter or "Butterfly"
bundles of (interneuron) cell bodies
a Central Canal
b. Gray commissure
c. anterior median fissure
White matter = myelinated axons
posterior or white column
lateral or white column
anterior or white column
provide 2- way system of communication
ascending tracts
locating in the posterior columns
descending tracts
lacted in the anterior impulses from brain to effectors
peripheal nervous system - nerves that extend from the brain and spinal cord
Sensory inpot functions
PNS:
Sensory recptors
Integrative functions
CNS
Motor Function
A motor impulse is carried on a motor neuron
Muscles
glades
Cell
The structurral & functional unit of the nervous system
Cell body = central portion of neuron
Dendrites
many per neuron
short and branched
receptive portion of a neruon
Axon
one per neuron
long thin process
carry impulses away from cell body
Axons in CNS
Myelin is produced by an oligodendrocyte
A bundle of myelinated nerve fibers
White matter
PNS + nerve
CNS = Thact column
Ganglin
huclesis
Cell body injury = death of neuron
Neuroglial Cells = accessory cells of nervous system
Oligondenocyte
looks like eyeball
Astrocytes
star -shaped
microglia
looks like a spider
Ependymal Cells
Epithelial - like layer
Sensory Neurons
afferemt neurons
Sematic receptors
Interneurons association
Link other neurons together
Multipolar neurons
bipolar neurons
Unipolar neurons
Two main components of the nervous system
CNS & PNS
two main compnents of the CNS
Brain & spinal cord
two main components of the PNS
Somatic & autonomic
two main components of the ENS
sensory motor
Two main components of the ANS
Sympathetic & Parastmpathetic
Three types of neurons
uni, bi, multi polar
four types of neuroglia cells in the CNS
ependymal, astrocytes, microglial, oligodendrocytes
two types of neuroglia cells in the PNS
Schwann Cells & Satellite cells