Chapter 12 and 13 Exam #3 Flashcards
compare and contrast the nervous system and the endocrine system
the nervous system directs immediate responses to stimuli and provides and interprets sensory information about external conditions; the endocrine system directs long-term changes in the activities of other organ system, adjusts metabolic activity and energy used by the body and controls many structural and functional changes during development
nervous system uses electrical signals and neurotransmitters to change cells and the endocrine system uses hormones to change cells
what are the different divisions of the spinal cord and what structures do they contain?
The central nervous system contains the brain and spinal cord. The peripheral nervous system contains everything else.
what are the functions of the division of the nervous system?
the cns is responsible for integrating, processing, and coordinating sensory data and motor commands. the pns delivers sensory information to the CNS and carries motor commands to peripheral tissues and systems.
how are the different divisions of the nervous system used?
the sensory division of the pns detects stimuli inside and outside the body. it sends the information to the brain in the CNS. the brain makes the decision and then activates the motor division of the PNS. the motor division activates the effector tissues.
what is the effector tissues
adipose tissue, glands, muscles
somatic sensory division
soma- body; bones, joints, superficial skin.
visceral sensory division
viscera- organs; organ pain and internal pain.
visceral motor division
smooth muscle, cardiac muscle, glands, adipose tissues; involuntary/ automatic muscle tissue. autonomic nervous system
somatic motor division
skeletal muscle tissue; the somatic motor division is the voluntary muscle tissue.
autonomic nervous system
parasympathetic vs sympathetic; rest and digest vs fight or flight.
sympathetic: dilate pupil. inhibit salvation, relax bronchi, accelerates heart, inhibit digestive activity, stimulate glucose release by liver (ATP), secretion of epinephrine and norepinephrine from kidney, relaxes bladder, contracts rectum
describe the general characteristics of neurons
the cell body (neurosoma), lots of dendrites, a single axon, and telodendria
cell body (neurosoma)
large centrally located nucleus with prominent nucleolus. organelles produce energy and synthesize. nissl bodies give the soma a grey coloring (grey matter)
dendrite
dendr=tree, ite=little; highly branched structures that participate in synapses; detect stimuli from other neurons. the more branching= the more information= better decisions; represent 80-90% of neuron surface area
axon
very long (up to 1 meter) cytoplasmic process; generally unbranches but may have axon collaterals. generate action potentials. first segment known as the initial segment will arise from thicker region of soma called the axon hillock; initial segment + axon hillock = trigger zone. axoplasm participates in axoplasmic transport; anterograde flow = soma to axon; retrograde flow = axon to soma.
telodendria
the terminal end of the axon is highly branches into telodendria to terminate as axon terminals (synaptic knobs) which are small bulbous structures full of neurotransmitters
sketch the major anatomical structures of a neuron
O<I———<;
body-dendrites-axonhillock-axon in between dashes and dashes are myelin sheath-ends are the telondria branching and the dots are the synaptic knobs
structural classifications of neurons
multipolar neuron: lots of dendrites attached to the cell body; most common
bipolar neuron: one dendrite and one axon attached to cell body; in places with senses
unipolar neuron: one single process but a dendrite going in and one axon going out. first order neuron
anaxonic: have more than two processes but no axons and only dendrites
functional classifications of neurons
sensory neurons (afferent): detect stimuli
interneurons: make decisions; 90% of all neurons
motor neurons (efferent): activate effector tissue
glial cells in CNS
astrocytes, oligodendrocytes, ependymal cells, microglial cells
glial cells in pns
satellite cells and schwann cells
what are glial cells
supporting cell sin the pns and cns
astrocytes
most numerous; form blood brain barrier using perivascular feet - seals gaps in blood vessels to filter what goes in and out of brain; structural framework; repair damaged nervous tissue
ependymal cells
produce and maintain cerebrospinal fluid; simple cuboidal E.T. ciliated
oligodendtrocytes
myelinate axons in CNS
microglial cells
phagocytic macrophages - large eaters; looks for cellular waste and pathogens
satellite cells
surround cell bodies; regulate interstitial fluid around the neuron
schwann cells
myelinate axon in PNS;
what is the basic structure of myelin
made from plasma membrane of the myelinating cell; 80% lipids and 20% proteins; myelination process begins about week 14 of fetal development and continues throught adolescence; corresponds with nervous system development
internode - segment of myelinated axons
node of ranvier - gaps of unmyelinated axons
myelination process in PNS
schwann cells physically wrap around the axon and makes lots of layers. squeezes cytoplasm out as it wraps. outermost layer is called the neurilemma; with nucleus and cellular machinery
myelination process in CNS
one oligodendrocyte will myelinate several internodes at once. sends out processes out and wrap from the outside in, no neurilemma
what are the functions of the myelin sheath
insulates the axon; separating the axon from the surrounding extracellular fluid.
increases conduction speed; conduction speed is how fast a signal can travel down an axon.
the larger the diameter the faster we send the signal and if its myelinated its faster; small, unmyelinated: .5-2m/s; large myelinated fibers: up to 120 m/s
4 types of membrane channels
leak or nongated channel (always open), chemically gated, voltage gated, mechanically gated,
multiple sclerosis
autoimmune disease; oligodendrocytes and myelin sheath in CNS deteriorate; the myelin is replaced by scar tissue; the scar tissues interferes with the transmission of signals in the nerves. symptoms: double/blurred vision, tremors, numbness, weakness and the paralysis - legs then arms
what is the charge of the resting membrane potential of a neuron
-70 mVl the inner surface of the plasma membrane is negatively charged with respect to the exterior
ICF is full of potassium ions and large anionic proteins = negative charge
ECF is full of sodium ions = positive charge
potassium ion gradients
at normal resting potential, an electrical gradient opposes the chemical gradient for potassium ions. the net electrochemical gradient tends to force potassium ions out of the cell.
sodium ion gradients
at normal resting potential, chemical and electrical gradients combine to drive sodium ions into the cell.
sodium-potassium pump
pumps 3 sodium ions out and 2 potassium ions in with every pump; requires 1 molecule fo ATP;
graded (local) potential
local stimulus that spreads a short distance usually in the dendrites and soma;
concentration gradient
icf is high in potassium ions and these ions tend to move through potassium leak channels; ecf is high in sodium ions so they move into the cell through sodium leak channels.
electrical gradient
there are more positive charges outside the plasma membrane and negatively charged protein molecules within the cytosol cannot cross the plasma membrane so there are more negative charges on the cytosol side of the plasma membrane.
excitatory post-synaptic potentials
brings postsynaptic cell closer to threshold
inhibitory post-synaptic potential
take the postsynaptic cell farther from threshold
3 characteristics of action potential
- all or none principle: if threshold is reached an action potential is formed
- non-decremental: the last action potential formed has the same strength as the first - doesn’t lose strength as it travels along the axon
- irreversible: once an action potential is created it can’t be stopped by non-pathological means