Neuro Anatomy review Flashcards
What is part of the CNS?
Brain
Spinal Cord
What is part of the PNS?
CN and branches
Spinal nerve and branches
What are extensions off of the soma, whose role is to basically receive any and all information coming that neuron’s way?
Dendrites
How do dendrites receive signals from other neurons?
by binding to neurotransmitters released from neighboring neurons
The signals received by the binding of neurotransmitters are interpreted where?
Soma (cell body)
Soma sends the now organized signal inputs straight to where, which is at the start of the neuron’s axon?
Axon hillock
What acts both as an insulator but most importantly as a conductor, it significantly increases the speed at which the action potential runs down the axon?
myelon sheath
With myelin present, how does that AP travel down the axon terminal?
AP jumps down the axon via the nodes of Ranvier
Role of oligodendrocytes?
production and maintenance of myelin
PNS equivalent to oligodendrocytes?
Schwann Cells
1 schwann cell creates how many myelin?
one area on one axon
1 oligodendrocytes creates how many myelin?
produce dozens of myelin internodes on multiple axons
Role of astrocytes? (3)
- Support cells
1. repair damage
2. regulate communication between neurons
3. maintenance of our blood brain barrier, which keeps toxic substances that may be circulating the blood stream from entering our brain
Role of ependymal cells?
- Line ventricle walls
2. Produce CSF
Role of microglia?
“Macrophages of the CNS” - remove foreign bodies
normal resting potential -
-70mV
Graded potential -
up to 15 mV
Depolarization -
positive charge = excites
Hyperpolarization -
negative charge = inhibits
Where is the electrical signal (graded potential) created in the neuron?
Axon hillock
T/F 1 Graded potential is not enough to do anything.
True, little potentials start adding up
What is the threshold for a neuron?
-55mV - Hit that threshold, and an action potential is formed that travels down the axon
Signal conduction if dependent on what 3 things?
- Fiber diameter (bigger the axon the more it can hold)
- Presence of myelin
- Thickness of myelin
How are axons graded by conduction velocity?
Type A, B, C from fastest to slowest
How are axons graded by fiber diameter?
Type I, II, III, IV from biggest to smallest
A/Ia =
- proprioception, stretch
- primary muscle spindle afferents
- motor efferents to extrafusal muscle
A/Ib =
Golgi tendon organ afferents - contractile tension
Ab/II =
- Mechanoreceptors: discriminative touch, pressure, joint rotation
- Secondary muscle spindle afferents (static muscle length)
Ay/II =
- Motor efferents to muscle spindle intrafusal fibers
Ad/III =
- Mechanoreception: touch
- Nociception: discriminative pain
B =
Autonomic preganglionic axons
C/IV =
- Nociception: inflammatory/visceral pain, thermal
- Autonomic postganglionic axons
Somatic nervous system -
- Voluntary movement
- spinal and CN
Autonomic NS -
- Involuntary control or autonomic processes
- Sympathetic and para
How many pairs of spinal nerves?
31:
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
Glutamate is what type of NT?
Excitatory
Gaba is what type of NT?
Inhibitory
Driving NT at the neuromuscular junction (NMJ)?
ACh
Motor unit -
motorneuron and the skeletal muscle fibers innervated by thatmotorneuron’s axonal terminals.
What is the postsynaptic target at the NMJ?
Motor end plate (muscle spindle)
Physical response during sympathetic (fight or flight) response?
Pupil dilation
Increased HR and BP
Blood vessel constriction to non-essential organs
Blood vessel dilation to essential organs
Stimulate liver glycogenolysis, and adipose lipolysis
Inhibit non essential body functions
Physical response during parasympathetic (rest and digest) response?
Pupil constriction
Increase salivation, lacrimation, urination, digestion, defecation
Decreased HR and BP
Decrease airway diameter
Monosynaptic reflexes involve what type of connections?
direct connections between sensory neurons and motor neurons, without any need for neurons in between
ex: spinal reflexes
Spinal reflexes -
- Monosynaptic reflex (DTR)
- normal muscle tone and mediate a number of simple motor responses
- reflex arcs that occur at the level of the spinal cord, without any involvement of the brain
- The brain receives information about the movement after it has been initiated
Polysynaptic reflexes -
- use INTERNEURONS to pass signals from sensory to motor neurons, creating multiple synaptic connections
ex: withdrawal stimulus