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
Trypotophin
an amino acid that is modified to make serotonin
What are classic neurotransmitters made from and where are they synthesized?
A single amino acid and are synthesized in the axon terminal
Neuropeptides are synthesized where?
perikaryal and dendrites;
What is the difference between classic neurotransmitters and neuropeptides
- classic are fast, onset, but quickly end
- neuropeptides don’t act quickly but have a longer life
Which part of a neuron has the lowest threshold?
Axon hillock
What is neuromodulation?
Raises or lowers the threshold
GABA
- classic neurotransmitter
- IPSP
- Most prevalent inhibitory of neurotransmitters in the CNS
- interneurons
Glutamate
- classic neurotransmitter
- EPSP
- most important for excitation
- amino acid
What are two types of neuropeptides
enkephalins and endorphins
absolute refectory period
- first in the refractory period of an axon
- not responsive no action potentials
relative refractory period
- second in the refractory period of an axon
- re-establishes resting potential
Synaptic Potentials
- enable one neuron to affect the other
- EPSP/IPSP
- graded/non-regenerative
EPSP(Excitatory Postsynaptic Potential)
- opens the sodium ion channels, which depolarizes the membrane possibly triggering an action potential
- Glutamate
IPSP(Inhibitory Postsynaptic Potential)
- Increases membrane permeability to potassium ions, which diffuse outward hyperpolarizing the membrane
- GABA
enkephalins
Generally inhibitory; reduce pain by inhibiting substance P release (CNS)
glutamate
Generally excitatory (CNS)
monoamine oxidase
- inactivates the monamine neurotransmitters epinephrine and norepinephrine after reuptake
- It is found in the mitochondria in the synaptic knob
serotonin
-Primarily inhibitory; leads to sleepiness; action is blocked by LSD, enhanced by selective serotonin reuptake inhibitor antidepressant drug(CNS)
tryptophan
-Serotonin
Dopamin
Creates a sense of well-being; deficiency in some brain areas associated with Parkinson disease (CNS)
Endorphins
Any group of neuropeptides synthesized in the pituitary gland and hypothalamus that suppress pain
Two parts of the ANS(Autonomic Nervous System)
Sympathetic & Parasympathetic
Sympathetic division
thoracolumbar output(spinal nerves) -fight or flight
Parasympathetic division
Craniosacral output(cranial nerves) -"rest and digest"
Vagul response
This happens when the vagus shuts the body down which is why we pass out
Which division has postganglionic neurons closer to the target organs?
Parasympathetic
Meninges
- located between the bones and the soft tissues of the nervous system
- they have three layers the dura mater, arachnoid mater, and the pia mater
ascending and descending tracts of spinal cord
- ascending tracts of the spinal cord are afferent information dealing with sensory neurons
- descending tracts of the spinal cord deal with efferent information and motor neurons
Peripheral Nervous system
Consists of Cranial and spinal nerves
Sensory receptors
- the ends of neurons in the pos provide the sensory function of the nervous system
- they gather information by detecting changes inside and outside of the body
autonomic nervous system
communicates instructions from the cns that control viscera, and thus causes involuntary subconscious actions; heart and various glands
interneurons
- they lie within the brain or spinal cord
- relay information from one part of the brain or spinal cord to another
projecting neurons
-broadly defined, projection neurons are neurons whose axons extend from the neuronal cell body within the central nervous system to one or more distant regions of the CNS.
Olfactory bulbs
-extensions of the cerebral cortex just beneath the frontal lobes
Optic chiasm
X-shaped structure on the underside of the brain formed by optic nerve fibers that cross over
Hypothalamus
- Part of the brain located below the thalamus and forming the floor of the third ventricle
- ANS: controlling our emotional side
Pituitary gland
-Endocrine gland attached to the base of the brain that consists of anterior and posterior lobes; the hypophysis
midbrain
-small region of the brainstem between the diencephalon and the pons
pons
-Part of the brainstem above the medulla oblongata and below the midbrain
cerebellum
- communicates with other parts of the CNS by tracts; integrates sensory information concerning the position of body parts; coordinates muscle activities and maintains posture
- Comparator
Medulla Oblongata
Part of the brainstem between the pons and the spinal cord
Tentorium cerebelli
- separates the occipital lobes of the cerebrum from the cerebellum
- it is a dural fold in the dural jacket
Somatic nervous system
-communicates voluntary instructions originating in the CNS to skeletal muscles, causing contractions
Which layer of the meninges is the most superficial?
Dura mater
The cerebellum is ____ to the brain stem?
Dorsal
Which occurs second int he refractory period of an axon?
relative refractory period
Descending tracts in the spinal cord are what?
Motor
T/F Hyperpolarization causes the membrane potential to become less negative?
False
T/F both unmyelinated and myelinated axons exhibit saltatory conduction
False
T/F The sympathetic division of ANS is known as “the fight or flight” response.
True
List one region/ part of the brains stem.
pons, medulla oblongata, midbrain
List one example of a neuropeptide
Endorphin, enkephalins, Substance P
What sensation is processed in the olfactory bulbs?
Smell
Which cranial nerves are only sensory?
1,2,8
What connects the hippocampus to the hypothalamus?
Fornix
What does hippocampus relate to?
memories
CN1 Olfactory Nerve
- only sensory
- receptors only found in nasal cavity
- goes into the olfactory bulbs then into the white matter tracts(olfactory tracts) that go into the cerebrum
Thalamus
- largest part of the diencephalon
- processes all sensations except for smell
Thalamic commisure
bridge that allows the two lobs to communicate and is only found in some people
Hypothalamus
- controls the ANS
- controls endocrine glands-makes a lot of hormones
- controls the pituitary gland
- center for desires= hunger, thirst, and sexual desires
Pineal gland
- melatonin is produced here
- biological clock - circadian rhythms
What is part of the diencephalon
thalamus, 3rd ventricle, hypothalamus, pineal gland, pituitary gland, optic chiasm, optic nerves2
What is the function of the superior colliculi?
gaze- directs eyes, neck, head to look at interesting things in our environment
What is the function of the inferior colliculi?
Only deals with sound, CN8, goes to thalamus, processes auditory information
In the brain stem where is sensory information processed?
Dorsal
In the brain stem where is motor information processed?
Ventral
What are the superior colliculi and inferior colliculi apart of?
midbrain
What connects the 3rd ventricle to the 4th?
Cerebral Aqueduct
Sternocleidomastoid
spinal accessory 11 and cervical spinal nerves 2-3. The origin and insertion can be flipped
Trapezius
- spinal accessory 11
- very superficial
- lies on top of rhomboid major
How many pairs of cervical spinal nerves are there?
8
What is the most superficial muscle in the body?
platysma
Which two muscles can flip flop origin and insertion?
pectoralis minor and sternocleidomastoid
What is going to establish the resting membrane potential?
Sodium and Potassium pump
What is the most prevalent ion in a cell?
Potassium
What is the most prevalent ion outside of a cell?
Sodium
What ion causes depolarization?
Sodium
Whats the most important ion for neuronal communication?
Sodium
EPSP+IPSP=?
Summation, which determines whether to fire an action potential
What are the three major groups of neurons based off of structural differences?
Multipolar, Bipolar, & Unipolar Neuron
Where can Multipolar neurons usually be found?
outside the brain and spinal cord
Where can Bipolar neurons usually be found?
specialized parts of the eye, nose, and ears
Where can Unipolar neurons usually be found?
ganglia
What are the three classifications of neurons based off of their functional differences
Sensory neuron, interneuron, and motor neuron
Sensory neurons are usually classified as what structure of neuron?
unipolar
What is the structure of an interneuron classified as?
multipolar
What structure is a motor neuron classified as?
multipolar
What are the four types of CNS neuroglia?
astrocytes, oligodendrocytes, microlgia, ependyma
What are the two types of neuroglia of the PNS?
Schwann cells and satellite cells