Nervous System
What are the embryonic origins of the nervous tissues?
Ectoderm germ layer
what is a reflex arc ?
when a stimulus triggers a sensory neuron to the cns and then a motor neuron responds Example: touching a hot plate and removing your hand
How does the rabies virus infect and damage the CNS?
Enters the peripheral nerve as viral coat protein binds to a neuron membrane receptor
retrograde transport moves the virus to the CNS
spreads to other organs
Treatment: wash wound, antiviral agents, vaccine , once progressed too far , hard to treat
Name the major support cells of the CNS and PNS. What are their functions?
What is a ganglion and a neural plexus?
CNS- astrocytes(BBB), microglial cells, ependymal cells and oligodendrocytes
PNS- schwann cells (help support neuron function by increasing speed of impulse propagation) and satellite cells
Gangalion - collection of cell bodies, axons bundled together
neural plexus- network of spinal nerves, creates major nerves in the body
Describe Neuromuscular Junction
1)ap arrives at nerve terminus
2) NT diffuses across synapse
3) NT is removed from synaspe
4) muscle depolarizes travles along t tubules
5)calcuim binds to troponin
6) contraction cycle begins
7) cacluim pumps return the ion to storage
8) tropomyosin reverts back to shape
9) muscle relaxes
Stem cells of nervous tissue give rise to what two basic types of cells. What do the neural tube and the neural crest cell form?
neurons and neuroglia
Neural tube form brain and spinal cord
neural crest form the skull and face
How do the following membrane structures function in the depolarization/repolarization
of the nerve cell - leak channels, ligand-gated channels, voltage-gated channels,
sodium/potassium ATP pumps? Include in your understanding of the process the various ions involved.
Depolarization- stimulus cause this to reach threshold (-55), sodium rushes in, and it reaches +30
Repolarization- sodium channel becomes inactivated, potassium rushes in (+30), the reversal of polarization takes place and passes back down pass threshold of -55 and hits the resting stage of -70.
Hyperpolarization happens when its below -70, potassium still present and sodium channel is at rest.
leak channels-needs connection to work, allows for sodium and potassuim to move across the cell
Ligand- NT binds to open channel, sodium is present
Voltage chnnel- closed until it reaches +30 , potassuim is present
Describe how the pre and post synaptic nerves work together and how they are regulated in action potential transmission.
pre and post synaptic cell can be affected
spatial and temporal
neurotransmitters can be positive and negative
pathway structure
Describe the circuitry and function of reflex arcs, including stretch, tendon and
flexor/crossed extensor.
Function of reflex arc is triggered by stimulus to send signals to cns to react to that stimulus
Stretch - portion of muscle, causes muscle contraction, determine body positions
Tendon- located in tendon, relax attached muscle, contracts antagonist muscle
Crossed - one leg withdraws, one leg is extended
contraction cycle
1) myosin heads hydrolyze atp to adp
2)myosin and actin binds
3) power stroke
4) new atp binds to relaxed myosin heads
Induction of the neural tube along the anterior posterior tissue is due to its close
proximity to which embryonic germ layer?
ectoderm
What factors can increase the speed of the nerve signal passing down the axon?
salfactory is faster than continous conduction, it increase nerve diamter which increases speed
Saltatory conduction- faster process, jumps node to node
continous conduction- makes it way down myelin sheath, slow process than saltatory
The brain and spinal cord are covered with three layers of connective tissue, name them.
dura mater-outer, pia mater- inner , arachnoid mater- middle
Describe the process of nerve cell differentiation along the brain/spine length.
•Stem Cells
–Ectodermal (neurons, most neuralglial cells)
–Mesodermal (microglia, connective tissue, blood vessels)
•Neural Tube
–Brain (Regions and Ventricles)
–Spinal Cord
–
•Neural Crest
–Ganglia
Peripheral Nerve
Disease or Defect
Rhadsarcoma, Als , Myas.Gravis,
hydrocheplus, alzehmiers, parkinsons
Describe the parts of the nerve cell – dendrite, cell body and axon. Cell bodies of
neurons are located where for the CNS and the PNS?
Dendrites- receive signals from neuron
cell body-houses the nucleus, lysosomes, mitochondria and golgi complex
axon- sends signals to other neurons, muscle fibers, or gland cell
CNS- cell bodies are located in the brain, spinal cord
PNS- all other location on the body
. What are some examples of different types of neurotransmitters? What is an agonist and
an antagonist?
Neurotransmitters- acetylcholine, glutamate, asparate, gamma acid, norepinephirine, epiriephrine,dopamine,serotinin etc
Agonist- nicotine
antagonist- curate
What are the spaces in between, particularly where does one find the blood and the
cerebrospinal fluid? How does the cerebrospinal fluid form, circulate and return to the
blood? See pages 530-535 of chapter 14
CSF is found in between four ventricles. lateral ( hemispheres of cerebrum, third ventricle ( near hypthalmus and thalamus), fourth (9 brai stem and cerebellum) and septum pellucidum
CSF is formed in the choroid plexus which flows to the third ventricle, passes midbrain and to the fourth ventricle. after reaching the FV, csf travels to the subarachnoid space, after it travels to the spinal cord. Its absorbed in the blood by arachnoid granulation.
too much csf? hydroceplhalus
How is the brain blood barrier established and how can it be broken?
BBB helps restrict movement of substances between the blood and interstial fluid of the CNS. it can be broken by trauma, toxins and inflammation
Proteins , Location on sarcomere , type of protein, function
Myosin and Actin are contractile proteins, They are located in the sarcomere of myofibrils, they generate force(muscle contraction)
troponin and tropomyosin are regulatory proteins. They help regulate muscle protein by switching it on and off , They are located on the actin filament.
Titin- Dystrophin are structural proteins to remain structure in the body system.
What general types of cells and tissues are organized in space between the surface of the
brain and the internal fluid-filled ventricles?
3 types of mater which is protective covering
Dura mater- tough fibrous outer layer
Pia mater- innermost layer, covered with blood vessels, bound to tissue, mesh of collagen fibers
arachnoid mater- middle layer , inner layer of this mater called superarachnoid space houses the CSF which cushions the brain and spinal cord
CSF circulates throughout and around the CNS and works continously with interstial fluid. When circulating removes metabolic waste from tissue and into blood stream.The choriod plexus plays a huge role.
For the receptor of the neurotransmitter acetylcholine, two general categories exist – nicotinic and muscarinic. How does cell signaling work for each of these types? Know examples of agonists and antagonists for each. If someone is poisoned by mushrooms with too much muscarine, how could they be treated?
Nicotinic Receptors- contains close cation channel, binds to acetyl. (NT)
Muscarinic Receptor- came from mushrooms, psychdelic, bind to acetyl. Antagonist of this receptor is atropine
If someone is poisoned by mushrooms, they would experience sweating, perspiration, lacrimation.treatment would be atropine
What are afferent and efferent tracts of nerves? How are the gray and white matter
arranged in the spine – including sensory vs motor, and somatic vs autonomic processing
centers? Distinguish between where the tracts enter and exit the spine and where the
processing centers are located.
Afferent (somatic)- go towards brain , mainly SENSORY
Efferent(somatic)- go away from brain , mainly MOTOR
Gray and white matter are arranged in the spine differently than brain, gray mater is on the inside and surrounded by white matter.