NEURONES Flashcards
Neurones are —— cells
Nerve cells
Neurones are said to evolve from?
primitive neuroeffecfor cells
Cns+pns= how many neurones
Cns=how many neurones
How many brain cells
trillions of neurones
100 billion neurones
25 billion brain cells
Brain and spinal cord are continuous with each other at ——-
Foramen magnum
List the 3 layers of meninges that surround brain and spinal cord
Outer dura matter
Middle arachnoid
Inner pia
What fills the subarachnoid space
CSF
Which is more , glial cells or neurons and by how much
Glial cells
10-50 times
Mention 2 unique things found in the soma of a neurone
Nissl bodies
Neurofibrils
What isn’t in the soma of a neurone
Centrosome- they can’t divide
Nissl bodies
Eosinophilic or basophilic
Basophilic
Parts of a neurone where nissl bodies can be found
Soma and dendrites only
Function of nissl bodies
Protein synthesis, they have ribosomes
Nissl bodies have —— appearance after staining
Tigroid appearance
Which part of a neuron can neurofibrils be found?
Every part of a neurone
Nodes of ranvier lack——
Myelin
Size of some Lengthof dendrite Length of axon Size of nodes of ranvier Distance between 2 nodes of ranvier
5-100um Few 100um Few um to 1m 1um 1mm
Mention 2 areas with very long axons
Pyramidal tracts-corticospinal
Peripheral nerves-nerve to limb(like sciatic nerve)
Myelin is a ____-_____
Protein-lipid
- produces myelin in cns
- produces myelin in pns
Oligodendrocytes
Schwann cells
Myelin. Continuous or not continuous
Not continuous
Veins drain nerves through ——?
Cerebrospinal fluid
Speed of myelinated nerve is — times that of unmyelinated nerve
50 times
Neuroglial cells
Excitable or non-excitable
Non-excitable
Common site of tumors in a nervous system
Neuroglial cells
Function of Astrocytes Ependymal cells Oligodendrocytes Microglia cells
Tight junctions to give Blood-brain barrier;regulate the extra cellular composition of the CSF
Form choroid plexus that secrete CSF; they also line the brain ventricles and spinal cord canal
Produce myelin and supportive function
Specialized macrophages
Functions of neuroglial cells of pns
Satellite cells
Schwann cells or neurolemmocytes
Surround cell body or soma
Produce myelin
Schwann can produce myelin to surround how many axons?
Just 1
4 zones of a nerve fiber
Receptor or dendritic zone
Initial segment
Axonal zone
Terminal zone
Pseudounipolar
Bipolar
Multipolar
Soma is attached to the side(cutaneous nerve)
Soma is in the middle (auditory neuron)
Soma is at the dendritic end
Relationship between diameter of a fiber, velocity of conduction, duration of spike, and duration of refractory period
Increase diameter-increase velocity-reduced spike time-reduced refractory period
Which fiber is most,less, and least susceptible to
Cocaine
Pressure
Hypoxia
Cocaine- most(C), less(B), least (A)
Pressure-most(A), less(B), least(C)
Hypoxia- most(B), less(A), least(C)
Which FIBER is for motor-muscle
A gamma
Which fiber is for pain, cold,touch
A delta
Which fiber is for touch, pressure motor
A beta
Which fiber is for proprioception and somatic motor
A alpha
Which fiber is for preganglion autonomic reflexes
B fiber
Gray matter is made up of
Nerve cell bodies and proximal parts of a nerve cell
White matter is made up of
Remaining part of nerve fiber besides the cell body and proximal part
Location of gray and white matter in brain and spinal cord
Brain: white inside;gray outside
Spinal cord: white outside;gray inside
Bundle of nerve fiber is called,
A fasiculus
Each nerve fiber is covered by?
The whole nerve is covered by ,
Endoneurium
Epineurium
Define Axoplasm Axolemma Axis cylinder Neurilemma
Cytoplasm of an axon
Continuation of cell membrane of soma
Axoplasm+axolemma
Covering of axis cylinder
What is responsible for the white color of nerves
Myelin sheath
Unmyelinated and myelinated fibers have Schwann cells
T/F
T
AKA of neurilemma
Sheath of Schwann/ neurilemmal sheath
Nucleus of the internode is located-?
Between myelin sheath and neurilemma
Cns have neurilemma
T/F
F. So they use oligodendrocytes
Cohnheim’s areas or fields
In some muscle fibers, some of the myofibrils are arranged in groups
A in A band stands for
I in I band stands for?
Anisotropic band: light gets refracted to different directions
Isotropic band:light is refracted at the same angle
Myosin has - light chains and -heavy chains
4 light; 2 heavy
2 heavy forms the tail
2 light forms each head
There’s myosin head in the H zone
T/F
F.
Who has longer chronaxie Adults or infants Red muscles or pale muscles Cold blooded or warm blooded animals High temperature or low temperature Paralyzed muscle or normal muscle
Infants Pale muscles Cold blooded Low temperature Paralyzed muscle
Differentiate between
Summation, superimposition and beneficial effect
second stimulus is applied during contraction period, or during second half of latent period;one curve
second stimulus falls during relaxation period of first twitch;2 curves;second Is greater
second stimulus falls after the relaxation period of the first curve; 2 curves;second is greater
Tetanus and fatigue in Skeletal Cardiac Smooth Nerve
S: possible;possible
C:not; not
Smooth: possible: not
N:no clue; not
Chemical process of relaxation of skeletal muscle
Active or passive
Active. It’s physical process is passive
Ph changes during contraction of skeletal muscle
Before: slightly alkaline
Start: acidic (atp breaks)
Middle: alkaline(atp forms back)
End: acidic(lactic acid formation
End plate potential
Propagative or non-propagative
Non propagative
Function. And origin of bungarotoxin
Deadly snakes
Blocks acetylcholine receptors
Function of Succinylcholine and Carbamylcholine
Act like ACH and keeps the muscle in a depolarized state
Function of Botulinum Toxin
Prevents release of Ach from the presynaptic terminal
Smooth muscle spike potential doesn’t reach isoelectric base
T/F
T
Muscular dystrophy involves the nervous system
T/F
F. It doesn’t
Describe:
Hypertonicity
Hypotonia
Increased muscle tone;no stretch
Decreased muscle tone;too much stretch
Kernicterus is caused by?
Brain damage by jaundice in infants
Myotonia is ?
Continuous contraction; delayed and slow relaxation
Terminal knobs are usually involved with with what?
Excitatory or inhibitory function
Excitation
Terminal waves or coils or free endings without nerve are usually involved with with what?
Excitatory or inhibitory function
Inhibitory function
3 examples of calcium channel blockers
Nifedipine
Verapamil
Diltaziem
Functions of A alpha fibers
Proprioception and somatic motor functions
Functions of Abeta fibers
Touch, pressure, motor
Which sensory receptor has its own motor supply
Muscle spindle
Function of Agamma fibers
Motor to muscle spindles
Function of Adelta
Pain cold touch
Sympathetic function of C nerve fiber
Post ganglionic sympathetic
Dorsal root function of C nerve fibers
Pain, temperature, some mechanoreceptors, reflex responses
Origin of 1a sensory fibers
Muscle spindle annulospiral ending
Origin of sensory fiber 1b
Golgi tendon organ
Another name for primary and secondary sensory nevers endings are?
Annulospiral; flower-spray spiral
Origin of 111 sensory fibers
Pain and cold receptors, some touch receptors
Origin of IV sensory fibers
Pain, temperature, dorsal rootC receptors
Stretch of muscle annulospiral spindle causes?
Stretch of golgi tendon organ causes?
Contraction
Relaxation
Axons end in ——- that are also a less ——-
Terminal buttons
Axon telodendria
Local responses are graded
T/F
T
Local responses can’t be summated.
T/F
F
AP can be measured with ——
RMP can be measured with ——
ERM or IRM
ERM
Difference between IRM and ERM?
Erm gives an approximate value of the time course
Why is a spark produced at 15mV when generating AP in a nerve cell
The depolarization from 7-15mV is too rapid
In cardiac action potential, what marks the end of phase 2?
Closure of Ca channels
When does SA node depolarize ?
When Ca is entering in cardiac AP
Difference between the repolarization phase in cardiac and skeletal AP
Cardiac-rapid
Skeletal-slow
