Test 3 Flashcards
What are the two cells of nervous tissue?
neurons and glia
Which cranial nerve controls the Lateral Ptyregoid?
V. Trigeminal Nerve
What is another name for a neuron’s cell body?
Perikaryon
What is another name for chromatophilic substance?
Nissl bodies
Nissl substance
Membranous organelles located in neuronal cell bodies and dendrites. Rough endoplasmic reticulum making peptide chains. It is not found in either axons or the axon hillock
Lower Motor Neurons are located where?
Brainstem and Spinal Cord
Which neurotransmitter does lower motor neurons use to communicate with the muscles?
Acetylcholine
How many pairs of spinal nerves are their?
31 pairs
Myasthenia gravis
Autoimmune disease that decreases cholinergic receptors. Acetylcholine is inhibited to help with this disease.
Rigor Mortis
stiffening of the body after death, contraction of the muscles.
Oligodendrocytes
- Glia of CNS found in high density in white matter
- produces myelin
Central Canal
Ventricle that contains Cerebral Spinal Fluid in center of spinal cord
Sarcoplasmic reticulum
Stores and sequesters calcium ions in muscle cells; smooth endoplasmic reticulum
Peristalsis
Smooth muscle contraction of tubular internal organs; digestive tract
I-bands
- Region of sarcomere with only actin present
- they shorten when sarcomere contracts
- held by direct attachments to structures called Z lines
Nodes of Ranvier
Unmyelinated regions of axons
tropomyosin
Protein located in grooves of actin that blocks myosin attachment
myosin crossbridges
- They connect to actin and pull actin toward the center, which contracts the sarcomere
- Loaded with ATP
Sliding filament hypothesis
the contraction of sarcomeres; theory of muscle contraction
myosin
proteins(thick & dark) that, with actin, forms the filaments that interact to contract muscle fibers
actin
Protein in a muscle fiber that forms the thin filaments(light) that slide between filaments of the protein myosin, shortening the muscle fibers.
Sarcomeres
the striations form a repeating pater of units along the muscle fiber
A-bands
the second part of the striation pattern, which composes thick myosin filaments overlapping thin actin filaments
ATPases
- an enzyme found in myosin heads
- it catalyzes the breakdown ATP to ADP and a phosphate
Tropomyosin
- rod-shaped and occupy the longitudinal grooves of the actin helix
- Prevents myosin cross bridges from binding/attaching to actin
Troponin
- High affinity for calcium
- attached to actin
Basic process of muscle contraction
Calcium is attached to troponin causing it to change shape and push tropomyosin out of the actin helix. With the removal of tropomyosin the myosin cross bridges can now attach to the actin, which causes the sarcomere to contract
Muscle relaxation
cross bridges have to be loaded with ATP, which allows the cross bridges to disconnect from the actin.
Triads
Region where the actin and myosin filaments overlap
Neuromuscular junction
- axon terminal of lower motor neuron
- synaptic cleft
- motor end plate
Motor end plates
-Where nuclei and mitochondria are abundant and the sarcolemma is extensively folded
Motor unit
controlled by a motor neuron and a muscle fiber
synaptic cleft
a small gap that separates the membrane of the neuron and the membrane of the muscle fiber
Neurotransmitter
Biological messenger molecules that convey neural information
3 ways to terminate a neurotransmitter
1) simple diffusion
2) enzymatic degradation
3) preuptake(pre-synaptic)
synaptic vesicles
tiny vesicles that stores neurotransmitters
dendrites
small cellular processes that receive input
axons
carries information away from the cell in the form of impulses
Schwan cells
- neuroglia that encase the large axons of peripheral neurons in lipid-rich sheaths(PNS)
- make the axons faster; insulates; myelinated
Saltatory conduction
jumps from Node of Ranvier to Node of Ranvier. Only on myelinated axons
Reflexes
- designed to be quick for protection reasons
- efferent information
- lower motor neurons
What makes action potentials different?
Frequency
How many neurons are involved in the patellar knee jerk reflex?
2 its the simplest reflex of the human body
Occulomotor
- comes off the midbrain
- highest cranial nerve
Axon hillock
multipolar neuron, the first part of the axon; makes the action potential
astrocytes
- provide support and hold structures together with abundant cellular processes
- aid metabolism
ependyma
form the inner lining of the central canal that extends downward through the spinal cord
choroid plexuses
- specialized capillaries associated with he ventricles of the brain
- they regulate the composition of the cerebrospinal fluid
myelin
-lipid material that forms a sheath like covering around some axons
Action potentials
Not graded all or nothing
-rapid change in the membrane potential
Receptor potentials
Graded
What is the most important job of the neuronal body?
Summation of EPSP and IPSP to determine whether or not to fire an action potential
Where are upper motor neurons found?
Cerebellum
axonal transport
enzymes required for neurotransmitter synthesis are produced in the cell body and transported to the axon terminals
Membrane potential
the potential difference across the cell membrane
Depolarization
- the membrane becomes more positive than the resting potential
- can be caused by sodium entering
- means the threshold is lowered for an action potential
Hyperpolarization
- if the membrane potential becomes more negative than the resting potential
- the threshold is raised
Which is bigger a mono peptide or a neuropeptide?
Neuropeptide
Name 4 cranial nerves with parasympathetic outputs?
3,7,9,&10
Vagus holds 75% of all parasympathetic fibers