Test 1 Flashcards
What does the nervous system play a dominant role in?
Coordination, association and integration
What are the parts of the CNS?
Brain and spinal cord
How many nerve trunks are there within the PNS?
86
How many cranial nerve pairs are there?
12
How many spinal nerve pairs are there?
31
Define ganglia
Groups of nervecell bodies within the PNS
Describe the somatic nervous system
Innervates skeletal muscle, has efferent and afferent nerve fibers, involves the CNS and PNS, it is cholinergic, only takes one neuron to get to the target
Define efferent
Goes away from the CNS
Define afferent
Goes toward the CNS
Describe the autonomic nervous system
innervates glandular epithelium, smooth and cardiac muscle, no conscious control, involes the CNS and PNS, has 2 subdivisions, sympathetic and parasympathetic
Describe parasympathetic control
Neurons are located in the CNS and PNS, only nerves that can carry efferent information in this system are cranial nerves 3, 7, 9, 10 and sacral nerves2, 3, 4 (craniosacral subdivision), requires 2 neurons to get to the target, preganglionic must be long and postganglionic must be short, both release ACH (rest and digest)
Describe sympathetic control
(Fight or flight), carry efferent fibers from T1 to L2, also require 2 neurons, the preganglionic must be short and the postganglionic must be long, preganglionic release ACH and postganglionic release norepinephrine, adrenergic system, except where ACH is released at the target are known (sweat glands and arrector pilli muscles)
Compare the sympathetic and parasympathetic nervous system
Have the opposite effect on the target, parasympathetic has a ratio of 1 preganglionic neuron to 2 postganglionic neurons, which makes it slower. The sympathetics have a ratio of 1 preganglionic to 17 postganglionic neurons, which makes it more widespread and less specific. Not everything has both sympathetic and parasympathetic neurons going to it
What is the third subdivision of the nervous system?
The intrinsic system of the gut, causes peristaltic reflexes within the gut, runs from the esophagus to the anus
Write out the diagram of the 3 primary brain vesicles.
See page 9 in notes for answer
Describe the flexures in development
The neural plate forms into the neural groove and the neural groove forms the neural tube
Which part of the embryonic brain is in the ventral side? Dorsal side?
Dorsal- cervical flexure
Ventral- cephalic flexure
How much does the brain weight at birth? When we’re an adult? How much oxygen do they use, respectively?
Baby- 10% of body weight, takes up 50-60% of oxygen
Adult- 2% of body weight, takes up 20% of oxygen
What does the neural tube give rise to?
CNS structures, like neuroepithelial cells
What do neuroepithelial cells give rise to?
Neuroblasts –> neurons
Glioblasts –> astrocytes and oligodendrocytes
Describe glioblast cells
Structural support for CNS, undifferentiated, can go through mitosis, give rise to astrocytes and oligodendrocytes. They are the functional connective tissue of the CNS and there are about 5-10x more glioblast cells than neurons in the adult human.
Describe astrocytes
They are the most numerous cell in the CNS, there are two types, protoplasmic (found in grey matter), and fibrous (found in white matter), they serve as structural support, are a part of the BBB, store what little glucose can be stored in the CNS and play a dominant role in forming scar like tissue after a CNS injurty
Describe oligodendrocytes
Less than astrocytes, but still numerous, two types, perineuronal cells (grey matter, possible nutrient role), interfascicular (white matter, form myelin around axons in CNS)
Describe ependymal cells
Line central canal and ventricles, serve as a leaky barrier, classified as simple cuboidal, secrete CSF.
Name and describe the different glial tumors discussed in class.
Astrocytoma (most common), glioblastoma (most lethal), ependymoma (block CSF from flowing, cause intracranial pressure)
Describe ganglia
Mesodermally derived, their phagocytic function is to clear dead and damaged tissue
Describe the neuroblast
They are along the neural tube, neuroblasts, depend on glial cells to help migrate, radiation and alcohol exposure in the embryonic stages can cause horrible effects to the fetus
Describe and draw out a unipolar cell
see page 15 of notes for picture found in DRG, visceral or somatosensory neuron
Describe and draw a bipolar cell
see page 15 of notes for picture 2 types- golgi type (long axon, descending part of spinal cord), golgi type II (short axon, more numerous)
Describe sensory neurons
Carry information toward the CNS, almost always in the PNS are the cell bodies. Afferent
Describe motor neurons
Carry information away from CNS, all cell bodies within CNS. Efferent
Describe internuncial neurons
Neurons that are entirely within the CNS
Describe commissural neurons
Neurons that are entirely within the CNS that go from one structure to the other exact structure.
Describe projection neurons
Neurons that are entirely within the CNS that go from one structure to a completely different structure
Describe ipsilateral neurons
Neurons that are entirely within the CNS that go from one structure to another on the same side of the CNS
Describe contralateral neurons
Neurons that are entirely within the CNS that go from one structure to another on different sides of the CNS
Describe intrasegmental neurons
Neurons that are entirely within the CNS that are in the spinal cord and begin and end on the same cord level
Describe intersegmental neurons
Neurons that are entirely within the CNS that are in the spinal cord and begin in one segment of the cord and end in a different segment of the cord
Refer to page 17, Figure 6 in the notes. Label each part of the multipolar neuron
:)
What shapes can the parikaryon be?
Round, oval, fusiform, stellae, pyramidal
Axoaxonic
Least common, come straight off the axon
Axodendritic
Axon connects to dendrites
Axosomatic
Axon connects directly to perikaryon
What are Nissl bodies?
Clumps of RER, ribosomes and iron
What is chromatolysis?
when the Nissl bodies respond quickly and appear to dissolve
Microtubules, microfilaments, neurofilaments. Put them in order from smallest to largest.
Microfilaments, neurofilaments, microtubules
What is axoplasmic transport? Describe the two types.
Movement of raw materials within the cell
Slow transport- intracellular movement of protein building blocks, anterograde, low energy, spread related to length
Fast transport- movement of synaptic vesicles, lysosomes and certain proteins, anterograde and retrograde, higher energy, not spread related to length.
Define neuron
the anatomical and functional unit of the nervous system
Define neuron process
an extension of the neuron away from its cell body
Define dendrite
a neuron process conducting an impulse toward the cell body
Define axon
a single neuron process carrying the impulse away from the cell body toward a synaptic or neuromuscular junction
Define hillock
a raised area of the cell body from which an axon arises
Nerve fiber
a dominantly long process of a neuron, usually an axon
Where are neurons ALWAYS myelinated? What cell creates the myelin? How do they form?
PNS, Schwann cell, they form a jelly-like roll
What cell myelinates the neurons in the CNS?
Interfascicular oligodendrocytes
What are the two things that determine the conduction velocity of a neuron?
Myelination, the more there is, the faster there is.
Axon diameter
What are the main differences between the connective tissue covers?
endoneurium is the innermost connective tissue covering and is highly vascularized
perineurium is the middle connective tissue and is elastic
epineurium is the outermost connective tissue covering and is virtually inelastic.
Define commisures
mid line white matter connectors inside the CNS
Define peduncles
a stalk or pillar-like formation of CNS white matter
What are some of the common CNS neurotransmitters?
ACH, NE, Dopamine, Serotonin, GABA, Glycine, Glutamate
What are some of the common neurohormones for the CNS?
ADH, oxytocin, Releasing Factor Neurohormones