Introduction to the Nervous System Flashcards
(83 cards)
1
Q
What is a neuron?
A
Functional unit of the nervous system
2
Q
What is a Soma?
A
Neuron cell body, nucleated region
3
Q
What are Dendrites?
A
Processes for receiving signals from neighboring neurons
4
Q
What is an Axon?
A
Process for sending signals to neighboring neurons
5
Q
What are Axon Terminals?
A
Site of synaptic signal transmission
6
Q
What is an Axon Hillock?
A
Site of connection between the soma and the axon
7
Q
What is a Myelin Sheath?
A
A Fatty, insulation of the axon, accelerates action potential
propagation
8
Q
What are Oligodendrocytes?
A
-Myelinating cells of the central nervous system (CNS)
-they are progenitor cells in processes of migration, proliferation & differentiation
-are fundamental to myelin formation & critical for myelin regeneration following injury
9
Q
What are Schwann Cells?
A
-Myelinating cells of the peripheral nervous system (PNS)
-provide support and insulation for axons
-are only able to myelinate single axons rather than multiple axons, contrary to oligodendrocytes
10
Q
What is the main function of the nervous system?
A
Initiate, regulate, coordinate, and integrate activity of muscles, organs, and all organ systems
11
Q
What stimuli does the nervous system respond to?
A
Both internal and external stimuli
12
Q
What does the nervous system involve?
A
voluntary and involuntary actions/reactions
13
Q
What are the major divisions of the nervous system?
A
The Central Nervous System (CNS) and Peripheral Nervous System (PNS)
14
Q
What is the CNS composed of?
A
- The Brain and Spinal Cord
-Which are the parts of the nervous system covered by the meninges
15
Q
What is the PNS composed of?
A
-Cranial Nerves: 12 pairs
-Spinal Nerves: 31 pairs
-made up of nerves and ganglia
16
Q
What is the Ganglion (pl. ganglia)?
A
a collection of cell bodies in the PNS
17
Q
What is a Nerve?
A
neuronal axons/processes in the PNS
18
Q
What color are cell bodies?
A
Gray
19
Q
What color are axons?
A
White
20
Q
Where are cell bodies located in the CNS?
A
The Nucleus
21
Q
Where are axons located in the CNS?
A
The Tract
22
Q
Where are cell bodies located in the PNS?
A
The Ganglion
23
Q
Where are axons located in the PNS?
A
The Nerve
24
Q
What are the meninges?
A
Membranes (connective tissue) that cover part of the CNS
25
What are the layers of the meninges?
3 layers:
Pia mater
Arachnoid mater
Dura mater
26
What location is the pia mater?
The innermost layer that’s closely adhered to the brain & spinal cord
27
What location is the arachnoid mater?
The internal layer between the pia and dura mater
28
What location is the dura mater?
The most external mater is the dura mater
29
What space contains CSF?
The subarachnoid space
30
What location is the subarachnoid space?
The space in b/t the pia mater & the arachnoid mater
31
What is the potential space?
It is b/t the dura mater & arachnoid mater, it only exist if a pathological condition occurs such as a subdural hematoma
32
Where is the epidural space?
-It lies b/t the dura mater and the bone
-separates the dura mater from periosteum lining of the bony wall of the vertebral canal
-the epidural space only exist b/t the vertebral canal
33
What is the function of the motor neuron?
Efferent – carrying information away from the CNS
34
Where is the motor neuron cell body located?
The brain, spinal cord, or ganglion
35
What is the motor neuron process of the dendrites?
Carry information to the cell body
36
What is the motor neuron process of the axon?
Carry information away from the cell body
37
What is the function of the sensory neuron?
Afferent – carrying signals towards the CNS
38
Where is the sensory neuron cell body located?
The brain or ganglion
39
What are the peripheral and central processes of the sensory neuron?
These processes are specialized to detect, receive, and transmit information directly to the CNS
40
What is a nerve made up of?
-A bundle of nerve fibers outside the CNS
-There are myelinated and unmyelinated nerve fibers
-They vary in size, number, and amount of myelin they contain
41
What are the three layers of connective tissue that surround the nerve?
Epineurium
Perineurium
Endoneurium
42
What is the Epineurium?
-the outermost layer of a peripheral nerve, composed of collagen fibers, fat, blood vessels, and lymphatics
-It provides structural support, blood supply, and protection from stretching and injury
43
What is the Perineurium?
-the middle layer of protective sheath that surrounds a nerve fascicle, composed of fibroblasts and perineurial cells
-It protects nerve fibers, is a metabolically active diffusion border, and maintains homeostasis of endoneurium
44
What is the Endoneurium?
-the closest layer around the myelin sheath that surrounds individual nerve axons and capillaries in peripheral nerves
-It separates and electrically isolates individual axons, and maintains endoneural fluid pressure
45
What is the vascular supply of the nerve?
Nerves are supplied by blood vessels called “vasa nervorum” that provide nourishment to the nerve fibers and their coverings
46
What is the organization of the CNS and PNS?
The PNS and CNS are anatomically and operationally continuous
47
What is the Anatomical Continuity of the CNS & PNS?
The most fundamental aspect of their anatomical continuity is the direct physical connection between the two systems:
-Spinal nerves of the PNS emerge from and enter the spinal cord, which is part of the CNS. These nerves contain both sensory (afferent) fibers carrying information to the CNS and motor (efferent) fibers carrying commands from the CNS
-Many cranial nerves originate directly from the brain (CNS) and extend to the head, face, and other parts of the body, forming part of the PNS
48
What is the Operational Continuity of the CNS & PNS?
The nervous system functions as a unified whole, with the PNS acting as the communication relay between the CNS and the rest of the body:
-The PNS gathers sensory information from the internal and external environments (e.g., touch, temperature, pain, sight, sound, internal organ states) and transmits it via afferent (sensory) nerves to the CNS for processing and interpretation
-The CNS processes this information and generates appropriate responses. These commands are then sent via efferent (motor) nerves of the PNS to muscles and glands, leading to actions (e.g., muscle contraction, gland secretion)
49
What are the options for nerves?
Nerves are either spinal, cranial, or derivatives of them
50
What is the spinal cord composed of?
gray matter and white matter
51
What does the gray matter contain?
cell bodies of neurons
52
What does the white matter contain?
bundles of axons
53
What are the Spinal Cord regions?
Anterior = ventral
Posterior = dorsal
54
What is the purpose of the Anterior Spinal Cord?
-This region will be associated primarily with MOTOR function
-Efferent (From) information
55
What is the purpose of the Posterior Spinal Cord?
-This region will be associated primarily with SENSORY function
-Afferent (To) information
56
Where are Cell bodies of motor neurons are located?
In the ventral portion of the gray matter
57
Where are Cell bodies of sensory neurons are located?
Outside of the spinal cord (just lateral to it) in structures called dorsal root ganglia
58
How does afferent information enter the spinal cord?
All afferent information that enters the spinal cord will enter via the dorsal horn
59
How does efferent information exit the spinal cord?
All efferent information exits the spinal cord via the ventral horn
60
What is each spinal nerve made up of?
-Ventral (anterior) root: axons of motor neurons
-Dorsal (posterior) root: centrally directed processes of sensory neurons
61
What does each dorsal root have?
Each dorsal root has an associated dorsal root ganglion
62
Is there a ventral route ganglion?
You only have a dorsal route ganglion, there is no ventral route ganglion
63
What are characteristics of spinal nerves?
Spinal nerves are very short; divide almost immediately into two branches which are the dorsal & ventral ramus
64
What is the function of the dorsal ramus?
-It supplies motor and sensory innervation of the skin and muscles of the back
-Remains separate from one another
65
What is the function of the ventral ramus?
-It supplies motor and sensory innervation of the ventral and lateral skin and muscles of the trunk and limbs
-Those distributed to the trunk remain separate
-Those pertaining to the limbs merge with one or more adjacent rami to form plexuses
66
Differences of the dorsal & ventral rami?
-Dorsal and ventral rami differ in their size and destination
-Ventral Ramus has a wider area for which it is responsible for innervating than the dorsal ramus does
67
Similarities of the dorsal & ventral rami?
-they both have the SAME component fibers
-they both have both motor and sensory innervation
68
What are the plexuses of the ventral ramus?
Cervical plexus
Brachial plexus
Lumbar plexus
Sacral plexus
69
What is the cervical plexus?
a network of nerves formed by the anterior rami of spinal nerves C1-C5 that supply the neck, thorax, and scalp
70
What does the cervical plexus innervate?
-Lesser occipital nerve (C2, 3): skin of the neck and the scalp posterosuperior to the clavicle
-Great auricular nerve (C2,3): skin over the parotid gland, the posterior aspect of the auricle, and an area of skin extending from the angle of the mandible to the mastoid process
-Transverse cervical nerve (C2,3): skin covering the anterior triangle of the neck
-Supraclavicular nerves (C3,4): skin over the neck and shoulder
-Ansa cervicalis (C1-3): infrahyoid muscles
-Phrenic nerve (C3-5): diaphragm, mediastinal pleura, pericardium of the heart
71
What are the sensory branches of the cervical plexus? Remember Mneumonic: Let's Go To Sleep
Lesser occipital nerve, Great auricular nerve, Transverse cervical nerve, Supraclavicular nerves
72
What are the motor branches of the cervical plexus? Remember Mneumonic: MAP
Muscular branches (sternocleidomastoid, prevertebral and levator scapulae), Ansa Cervicalis, Phrenic nerve
73
What is the Brachial plexus?
-a network of nerves that innervates the upper limb
-this plexus arises from the anterior rami of spinal nerves C5-T1 that undergo several mergers and splits into trunks, divisions, and terminal branches
74
What are the terminal branches of the brachial plexus responsible for?
motor and sensory innervation of the upper limb, and they include the musculocutaneous, axillary, radial, median and ulnar nerves (terminal branches)
75
What are the roots of the Brachial Plexus?
C5, C6, C7, C8, T1
76
What are the trunks of the Brachial Plexus?
Superior trunk
Middle trunk
Inferior trunk
77
What are the three anterior divisions of the Brachial Plexus?
- Anterior division of superior trunk
- Anterior division of middle trunk
- Anterior division of inferior trunk
78
What are the three posterior divisions of the Brachial Plexus?
- Posterior division of superior trunk
- Posterior division of middle trunk
- Posterior division of inferior trunk
79
What are the cords of the Brachial Plexus?
Lateral
Medial
Posterior
80
What is the organization of the Brachial Plexus? Remember Mneumonic!
Rugby Teams Don't Cover Bruises'
(standing for: Roots, Trunks, Divisions, Cords, Branches
81
What are the Lateral cord branches of the Brachial Plexus? Remember Mneumonic!
Rugby players are Long Legged Movers'
(standing for: Lateral pectoral nerve, Lateral root of median nerve, Musculocutaneous nerve)
82
What are the medial cord branches of the Brachial Plexus? Remember Mneumonic!
Rugby players Make Many Moves Using Muscles'
(standing for: Medial cutaneous brachial nerve, Medial cutaneous antebrachial nerve, Medial pectoral nerve, Ulnar nerve, Median root of median nerve)
83
