Anatomy-Endterm Flashcards
1
Q
Function of cartilage
A
- Bear mechanical stress
- Shock-absorber
- Essential for growth and development of bone
2
Q
Characteristics of cartilage
A
- Has periosteum that surrounds on all sides of the cartilage
- Made of chondrocytes that are within lacunae
- Ground substance has proteoglycan and hyaluronic acid which absorbs stare so when you touch it, it comes back like a spring
- Avascular and no nerve supply
3
Q
Cartilage development
A
- Mesenchymal cells differentiate into chondroblasts
- Chondroblasts mitotically divide and form isogenic groups
- Chondroblasts secrete the ECM
- ECM captures the chondroblasts and divides them into separate cells called chomdrocytes
4
Q
Chondrocytes
A
Can’t divide and mature cartilage cells
5
Q
Interstitial growth
A
Growth that results from the chondroblasts. It goes along the length
6
Q
Appositional growth
A
Growth that happens in the perichondrium and grows along the width
7
Q
Hyaline cartilage
A
- Contains collagen type II fibrils and ground substance
- Has perichondrium all around it
- Fresh hyaline cartilage is whitish-bluish
- In the embryo:forms the temporary skeleton
- Chondrocytes that are active show basophilia along the lacunae
- Inactive chondrocytes have white spaces which is for glycogen storage and fat droplets
- Matrix calcifies
- Supports structures and is flexible
- Found in articulations cartilage, nasal septum, epiphyseal plate, respiratory passages
8
Q
Articular cartilage
A
Does not have perichondrium . So get nutrients from diffusion of the synovial fluid
9
Q
Epiphyseal plate
A
Doesn’t have perichondrium
10
Q
Perichondrium
A
Dense irregular connective tissue that has vascularity and blood supply and provides it to the avascular cartilage
11
Q
Elastic cartilage
A
- Has elastin and collagen type II fibers
- Matrix doesn’t calcify
- Has perichondrium around it
- Provides support and maintains shape of structure
- Ex: outer part of ear, external auditory canal, epiglottis of larynx
12
Q
Fibrocartilage
A
- Mostly has collagen type I fibrils but also has collagen type II fibrils
- Chondrocytes are arranged by themselves or in isogenous groups in rows
- In between the rows, there are collagen type I fibers
- No perichondrium
- Matric calcifies
- Is acidophilic due to collagen type I
- Function is support and rigidity
- Ex: meniscus, intervertebral disc, pubic symphysis
13
Q
Function of bone
A
- Protection
- Movement
- Creating blood vessels in the bone marrow
- Storing Ca and P
14
Q
Compact bone
A
Composed of longitudinal circular structures called osteons or Haversians
Help resist stress
15
Q
Lamella
A
Concentric rings around the central part. Used to find the age of the bone
Between lamellae are lacunae consisting of osteocytes
16
Q
Cannaliculi
A
Projections of the lacunae that connect with one another to provide nutrients and blood supply.
Filled with extracellular fluid
17
Q
Spongy Bone
A
Does not have osteons. Instead lamellae are arranged in a sheet with spaces in them called trabiculae (help make the bone lighter)
Hematopoeisis occurs in spongy tissue. Each trabiculae has lamina consisting of osteocytes
18
Q
Trabiculae
A
Lines across areas of stress. Blood fills the spaces of the trabiculae and this nourishes osteocytes
19
Q
Osteopenia or progenitor cells
A
Mesenchymal cells that will form osteoblasts
20
Q
Osteoblasts
A
Mitotically active cells that divide and give rise to osteocytes.
Work in teams to make new bone called osteoid
Help deposit calcium and minerals into the bone
Found at the edge of bone
21
Q
Osteoclasts
A
Derived from monocytes
Break down bone and bring calcium from the bone to the bloodstream. So blood Ca levels are regulated by osteoclasts
Found at the edge of bone
22
Q
Osteocytes
A
Mature, non-dividing cells trapped in lacunae
23
Q
Ossification
A
Happens in embryological development from week 6-8
2 types:
- Intramembranous
- Endochondral
24
Q
Intramembranous ossification
A
Mesenchymal tissue is replaced by ossified tissue. Osteoblasts begin to appear and form spongy bone. Spongy bone is remodeled to form compact bone
25
Endochondral ossification
Cartilage provides the framework of the bone. Osteoclasts will begin to digest the cartilage in the diaphysis and osteoblasts will lay down new bone. Blood vessels will begin to emerge and the medullary cavity will hollow out. Blood vessels and osteoblasts will then go to the epiphysis
Cartilage will remain only at the articular surface and epiphyseal plate
26
Primary center of ossification
Diaphysis
27
Secondary center of ossification
Epiphysis
28
Growth of bone
Osteoclasts will eat up a portion of the epiphyseal plate and then osteoblasts will put in new bone
When a person becomes an adult, epiphyseal plate will become epiphyseal line
29
Repair of bone
- Form fracture hemmatoma: clots blood
- Fibrocartilage callus formation: fibroblasts invade the site and form collagen fibers to bring the broken pieces of bone together
- Bony callus formation: osteoblasts will form bone
- Bone remodeling: spongy bone is converted to compact bone
30
Bone takes so long to heal...
Since calcium and phosphorus are deposited gradually over a period of months
31
Calcium and phosphorus
Helps harden bone
32
Types of muscle tissue
- Skeletal: allows movement and attached to bone
- Cardiac
- Smooth: found in the walls of hollow contracting organs (blood vessels, urinary bladder, digestive tract)
33
Function of muscle
- Protection
- Movement
- Generating heat through involuntary contraction of skeletal muscles
- Posture
34
Properties of muscle tissue
- Excitability
- Condunctivity
- Elasticity
- Contractability
- Extensibility
35
Histology of skeletal muscle
Is striated, long, multinucleated, voluntary
Has 3 CT coverings: epimysium, perimysium, and endomysium
Cells don’t divide
36
Epimysium
Dense irregular connective tissue that covers fasicles
37
Perimysium
Collagen and elastin fibrous connective tissue in between fasicles
38
Endomysium
Reticular connective tissue in between muscles cells/fibers
39
Fascia
Covering outside of the epimysium
40
Tendon
Cord-like extension of outer fascia that connects a muscle to bone
41
Muscle belly
Portion of muscle in between tendons
42
Musculotendinous junction
Part where the epimysium comes together to form a tendon
43
Aponeurosis
Broad sheet-like extension of pearly-white fibrous tissue of deep outer fascia
44
Raphe
Seam like aponeurosis
45
Skeletal muscle cells
Multinucleated and are striated, voluntary, and don’t divide
Don’t have cellular junction
46
Satellite cells
Stem cells at the edge of skeletal muscle cells that can differentiate into cells when there is an injury
47
Sarcoplasm
Cytoplasm of muscle cells
48
Sarcoplasmic reticulum
ER of muscle cells
49
Sarcolemma
Cell membrane of muscle cells
50
Forming skeletal muscle cells
Hundreds of myoblasts come together and fuse
51
Growth of skeletal muscle cells
Can’t divide so growth is through enlargement of the cell
52
T-tubules
Helps conduct impulses. Leads to Ca release when an AP has been produced. Go into the sarcoplasmic reticulum
53
Role of calcium
- Stored=relaxed
| - Released=contraction
54
Myofibrils
Have a lot in muscle cells. They have thick and thin microfilaments which are responsible for contraction
55
Striation of muscle cells
Have two bands
- Light band (I band)
- Dark band (A band)
56
I band
Is the light band. Has a freak line in the middle called the Z disk
57
A band
Is the dark band. Has a light region in the center called the H zone and a dark line called the M line
Can only see the H zone is relaxed cells, not contracting one
58
Thick myofilament
Made up of myosin.
Each myosin looks like 2 golf heads intertwined together
Extend towards the thin filaments and bind to it
Held in place by the M line
59
Thin myofilament
Made of actin, tropomyosin, and troponin
Held in place by the Z disk
60
Neuromuscular junction
The junction between the skeletal muscle cell and the nerve fiber
61
Cardiac muscle cells
Striated, involuntary, highly branched, single central nucleus
Cells are connected by intercalated discs
Has only endomysium
Has T tubules+sarcoplasmic reticulum
No neuromuscular junction+mitosis
62
Intercalated discs
Contains gap junctions and desmosomes which allows the cells to work in syncytium
63
Smooth muscle cells
Involuntary, small, tapered, central nucleus
Can divide and regenerate
Form 2 sheets: longitudinal+circular
Has only endomysium
No T-tubules and sarcoplasmic reticulum
Has gap junctions and no neuromuscular junction
64
Longitudinal sheets
Wide and short lumen
65
Circular
Long and narrow lumen
66
Regeneration of smooth muscle
Can grow (hypertrophy) and some can divide (hyperplasia)
New fibers can form from stem cells in the blood vessel walls
67
4 classifications of skeletal muscles based on fasicle arrangement
- Parallel
- Convergent
- Pennate
- Circular
68
Parallel classification
Most common classification. These muscles are not that strong
69
Strap-like broad attachment
So basically aponeurosis.
Ex: satorius and sternohyoid
70
Strap-like with tendinous intersections
Rectus abdominus
71
Strap like with muscle belly
Has a tendon in between muscle
Ex: biceps brachii
72
Convergent muscles
All meet up at one point. They are triangular or fan-shaped
Ex: pectoral is major
73
Pennate
They attach to the intersection at one point (unipennate), two points (bipennate), or many points (multipennate)
Have the highest concentration of fibers and are the most powerful muscles
74
Unipennate
Attaches at one point
Ex: exterior digitorum longus
75
Bipennate
Attaches at two ends
Ex: Rectus femoris
76
Multipennate
Attaches to bone at many sides
Ex: deltoid
77
Circular muscles
Arranged in concentric rings around an external body opening
Ex: orbicularis oris muscle
78
Functional muscle groups
Can be divided into:
- Agonist
- Antagonist
- Synergists
- Fixators
79
Agonists (prime movers)
Muscles that provide the major force for flexion
Ex: biceps brachii in the flexion of the arm
80
Antagonists
Go against the force of the agonist
Ex: triceps brachii in elbow flexion
81
Synergists
Muscles that stabilizes the agonists and antagonists and makes sure it doesn’t rotate
Ex: brachialis in elbow flexion
82
Fixators
Muscles that fix against bone so that the bone doesn’t move as well
Ex: serratous anterior muscle attaches the scapula to the thorax during arm movement
83
Rectus
Fasicles are arranged vertically
Ex: Rectus abdominus
84
Transversus
Fasicles are arranged horizontally
Ex: transverse abdominus
85
Oblique
Fasicles are arranged diagonally
Ex: External oblique
86
Brachium
Arm
87
Frontalis
Near the frontal bone
88
Occipitalis
Located near the occipital bone
89
Externus (superficialis)
Visible at the body’s surface
90
Internal (profundus)
In deep muscles
91
Externalis
Muscles outside organs
92
Internalis
Muscles inside an organ
93
Minumus
Smallest
Ex: gluteus minimus
94
Medius
Middle
Ex: gluteus minimus
95
Maximus
Largest
Ex: gluteus maximus
96
Longus
Longest
Ex: fibularis longus
97
Brevis
Shorter than longus
Ex: fibularis brevis
98
Tertius
Shortest
Ex: fibularis tertius
99
Biceps
2 heads
Ex: biceps brachii and biceps femoris
100
Triceps
3 heads
Ex: triceps brachii
101
Quadriceps
4 heads
Ex: quadriceps femoris
102
Deltoid
Triangular-shapes
103
Serratous
Saw-toothed shape
104
Teres
Round or cylindrical
105
Rhomboidus
Rhomboid shape
106
Trapezius
Trapezoid shapes
107
Flexor
Decreases angle
Ex: flexor carpi radialis
108
Extensor
Increases angle
Ex: extensor carpii ulnaris
109
Abductor
Moving away from midline
Ex: abductor pollicus longus
110
Adductor
Moving towards the midline
Ex: adductor longus
111
Levator
Moves upwards
Ex: levator scapulae
112
Depressor
Moves downwards
Ex: depressor labii inferioris
113
Supinator
Moves palm up
114
Pronator
Moves palm down
Ex: pronator teres
115
Motor fibers
Make up 60% of innervated nerves
Have 3 types:
- Large alpha myelinated efferents which supply extrafusal muscle fibers
- Small gamma unmyelinated efferents which supply intramural muscle fibers
- Fine non-myelinated efferents which supply blood vessels
116
Neuromuscular junction
Axon terminal lies in a trough-like depression
Also has a unique basal lamina that is not in synapses of neurons
117
Basal lamina
Contains acetylcholinesterase which makes sure that only one twitch happens at a time
118
Sensory fibers
Make up 40% of innervated nerves
Have 2 sensory fibers:
- Primary sensory ending (anulospiral ending): in intrafusal fibers and innervated the nucleus
- Secondary sensory endings (flower-spray endings): in intrafusal fibers and innervate areas around the nucleus
119
Muscle spindle
Made up of intrafusal muscle fibers and act as stretch receptors
Help regulate rate and contraction of extrafusal muscles by influencing alpha neurons
120
Head
Superior part of the body that connects to the trunk by the neck
Houses the brain
121
Function of head
- Helps in identity
- Masticulatory devices (chewing)
- Has special sensory organs
- Beginning of food intake
- Respiration
122
Skull
Skeleton of the head that is divided into the viscerocranium and neurocranium
Has sutures that are mostly fibrous joints. Only movable joint is the temporimandibular joint
123
Neurocranium
Houses the brain. Consist of the skull cap (calvaria) and cranial base
124
Skull cap (calvaria)
- Frontal
- Parietal
- Occipital
125
Cranial base
- Temporal
- Sphenoidal
- Ethmoidal
126
Viscerocranium
Houses the other organs of the face. Made of 15 bones including
- Maxilla
- Mandible
- Orbit
- Vomer
- Zygomatic
127
Superior aspect of cranium
Has the frontal, parietal, and occipital bones
Has three sutures: sagittal, coronal, and lamboid
Formen: parietal emissary foremen
Landmarks: lambda, bregma
128
Lateral aspect of cranium
Bones: frontal, parietal, occipital, temporal
Landmarks: asterion (occipital bone), pterion (parietal bone), mastoid process
Sutures: coronal and lamboid
Foramen: mastoid emissary foramen
129
Fasciae aspect of cranium
Bones: frontal, temporal, zygomatic, mandible, maxilla, lacrimal
Sutures: intermaxillary and internasal
Landmarks nasion (connecting internal suture to something else)
Foramen: infraorbital, mental, supraorbital
Cavities: nasal and orbital
130
Posterior aspect of cranium
Bones: occipital, parietal
Sutures: sagittal and lamboid
Landmarks: lambda
131
Basal view of cranium
Divided into anterior, middle, and posterior parts
132
Anterior basal part
- Hard palate: roof of the oral cavity and divided into palatine process of maxilla and horizontal process of palatine bone
- Posterior nasal aperture
133
Middle part of basal part
- Infratemporal and pharyngeal regions
| - Temporal, sphenoid, and basal part of occipital bone
134
Posterior basal part
- Foramen magnum
| - Occipital bone
135
Incisive foramen
Located in the palatine process of the maxilla
Has the nasopalatine nerve and greater palatine artery
136
Greater and lesser palatine foramen
Located in the horizontal process of palatine bone
Greater and lesser palatine vessels pass through it
137
Foramen ovale
Located in sphenoid bone
Contains:
- Mandibular nerve
- Accessory meningeal artery
- Lesser petrosal nerve
- Emissary vein
138
Jugular foramen
Located in temporal bone
Contains 9,10,11 cranial nerves and sigmoid sinus
139
Carotid canal
Located anterior to jugular foramen
Contains internal carotid artery
140
Stylomastoid foramen
Located lateral to jugular foramen
Contains facial nerve and 7 cranial nerve
141
Mastoid foramen
Located in the mastoid process
Contains emissary vein
142
Hypoglossal canal
Near the condyles of the occipital bone
Contains the hypoglossal nerve
143
Formen magnum
Contains the medulla oblongata
144
Cranial fossa
Divided up into anterior, posterior, and middle parts
145
Anterior cranial fossa
- Orbital plate of frontal bone
- Cristal galli
- Cribiform plate of ethmoid bone
146
Middle cranial fossa
- Pitutary fossa
- Petrus part of temporal bone
- Foramen ovale
- Foramen rotundum
- Optic canal
- Superior orbital fissure
147
Posterior cranial fossa
- Basilar part of occipital bone
- Squamous part of occipital bone
- Formen magnum
- Groove for sigmoid sinus
148
Walls of cranial cavity
Divided into anterior, middle, and posterior regions
149
Anterior wall of cranial cavity
- Orbital plate of frontal bone
| - Cribiform plate of ethmoid bone
150
Middle wall of cranial fossa
- Sphenoid
| - Temporal bone
151
Posterior wall of cranial cavity
-Occipital and temporal bone
152
Lateral wall of cranial cavity
- Frontal
- Parietal
- Temporal
- Occipital
153
Anterior and posterior ethmoidal foramen
Anterior and posterior ethmoidal nerves and vessels
154
Cribiform foramen
Olfactory nerves
155
Optic canal
Optic nerve and ophthalmic artery
156
Foreman rotundum
3 cranial nerve
157
Formen spinosum
- Middle meningeal vessel
| - Nervous spinosus
158
Internal acoustic meatus
7 and 8 cranial nerve
159
Dural folds
Double layers of the meningeal part of the dura matter that form pouches
Include:
- Falx cerebelli
- Falx cerebri
- Tentorium cerebelli
160
Dura matter
Made of 2 layers
- Endostinal: more superficial
- Meningeal: more deep
161
Dural venous sinus
- Superior and inferior sagittal sinus
- Sigmoid sinus
- Transverse sinus
- Staight sinus
162
Scalp
Soft tissue covering cranium
Borders:
- Posterior: superior nuchal line of occipital bone
- Lateral: superior temporal line
- Anterior: supraorbital margin
163
Layers of scalp
- Skin: is thin and has many sweat and sebaceous glands and hair follicles and is very vascular so heals quickly
- Dense connective tissue: subcutaneous tissue that binds to skin
- Aponeurosis: strong tendinous sheet that covers the skull
- Loose CT: sponge like CT that allows free movement and blood to accumulate when there’s injury
- Periosteal: bone
164
Subcutaneous muscle
Binds to skin and not muscle which is why we can do fascial expressions
Develops from the 2nd pharyngeal arch in the mesoderm and is innervated by motor branches of the fascial nerve
165
Muscles of scalp
Occipitofrontalis muscle
166
Muscles of eye
Orbicularis oculli
167
Muscles of nose
- Nasalis
| - Levator labii superioris alaeque nasi
168
Muscles of mouth
- Orbicularis oris
- Buccinator
- Levator labii superioris
- Depressor labii inferioris
- Zygomatic major and minor
169
Muscles of ear
-Auricularis superior, posterior, and anterior
170
Muscles of neck
Platsyma
171
External carotid artery
Gives rise to:
- Fascial: superior labial, inferior labial, lateral nasal, nasal branches
- Maxillary: mental and infraorbital
- Occipital
- Posterior auricular
- Superficial temporal
172
Internal carotid
Gives rise to ophthalmic artery
173
Arteries in front of ear
- Branches of ophthalmic: supraorbital and supratrochlear
| - Branches from external carotid: superficial temporal
174
Arteries behind ear
Branches from external carotid: posterior auricular, occipital
175
Angular vein
Formed from supraorbital and supratrochlear
176
Fascial veins
Continuation of angular
Recieves external nasal and superior+inferior labial
177
Retromandibular vein
Formed from superficial temporal and maxillary
Divides into anterior and posterior divisions
178
Common fascial vein
Formed from fascial and anterior of retromandibular
Drains into internal carotid
179
External jugular vein
Posterior division of retromandibular and posterior auricular
Drains into subclavian vein
180
Internal jugular vein
Continuation of sigmoid sinus
181
Superior and inferior ophthalmic veins
Drains into cavernous sinus
182
Trigeminal nerves (5th cranial)
- Opthalmic division: supratrochlear and supraorbital
- Maxilla: infraorbital
- Mandible: superficial temporal and mental
183
Dorsal rami of spinal nerves
- Greatre occipital (C2)
| - 3rd occipital (C3)
184
Cervical plexus
- Lesser occipital (C2,3)
| - Greater auricular (C2,3)
185
Sensory in front of ear
- Supratrochlear
- Surpraorbital
- Zygimaticotemporal
- Auriculotempotal
186
Motor in front of ear
Fascial nerve (temporal branch)
187
Sensory behind the ear
-Dorsal rami of spinal nerves
188
Behind the ear motor
Posterior auricular branch of fascial nerve
189
Superficial ring of lymph nodes
- Occipital
- Mastoid
- Parotid
- Buccal
190
Deep cervical lymph nodes
Located along internal jugular vein
Superior and inferior nodes: jugulodigastric and jugulo-omohyoid
Jugular lymphatic duct: drains into junction of internal jugular and subclavian vein
191
Nervous system
Made of the central and peripheral nervous systems
192
Peripheral nervous system
Transmits information from and to the nervous system by efferent and afferent neurons respectively
193
Function of nervous system
- Reception of information from external and internal environment
- Integrate and analyze incoming information
- Generate new info
- Conduct signal time efferent tissue
194
Neurons
Star-shaped cells that transmit electrical signal
195
Support cells
Also called glial cells and are not excitable and surround neuron
196
Characteristic of neurons
- Longevity
- Can’t divide
- High metabolic rate
197
Parts of neuron
- Cell body
- Axon
- Dendrite
198
Axons
Long and thin and transmit information from cell
199
Electrical impulses are always...
One direction
200
Cell body
All protein production happens here since Nissl body (endoplasmic reticulum) is here
201
Nuclei
Clusters of cell body in CNS
202
Ganglia
Cluster if cell bodies in PNS
203
Nissl stain
Won’t show up in the axons or dendrites
204
Dendrites
Extension from cell body and receives information
205
Strength of axon
Due to cytoskeleton
206
Anterograde transport
Carries proteins to axon
207
Retrograde transport
Brings back proteins to cell body
208
Action potential
Generated at axon hillock. Ca enters and allows neurotransmitter to be released
209
Telodendria
Unmyleinated ends of the axon. Have support cells around it for support
210
Bouton
Bulb at end of telodendria that helps release neurotransmitter
211
Synapse
Junction from one neuron to another cell or neuron
212
Neuromuscular synapse
Between neuron and muscle
Always use acetylcholine
213
Neuroglandular
Between one neuron and a gland
214
Presynaptic neuron
Transmits the impulse
215
Postsynaptic neuron
Recieves the impulse
216
Electric synapses
Occurs between two dendrites through gap junctions
Rare in the CNS and PNS
Allows groups of cells to work together as a single unit
217
Chemical synapses
Between an axon and a dendrite and chemicals are released
218
Excitatory ion channel synapse
Opens Na channels allowing depolarization
Ex: glutamate, aspartate, acetylcholine
219
Inhibitory ion channel synapse
Allows chlorine to enter leading to hyperpolarization
Ex: glycine and GABA
220
Axodendritic
Between axon and dendrite
Most common type
221
Axosomatic
Between axon and cell body
222
Axoaxonic
Between axon and axon
Less common
223
Dendrosomatic
Between dendrite and cell body
224
Unipolar or pseudounipolar
Has only one process from cell body
One process divides into 2: one receiving and one giving information
Unipolar neurons used to be bipolar
225
Bipolar
Has 2 process
Found in rare neurons in special sensory organs (eye)
226
Multipolar
Has many dendritic processs and common axon
Very common
227
Sensory neurons
Also known as afferent neurons. Are unipolar neurons that go to dorsal root of spinal chord. Some are bipolar
Cell body is located in ganglia (dorsal root)
228
Motor neurons
Efferent neurons that are multipolar. Cell bodies are located in ventral root in spinal chord
229
Interneuron
Connects the motor and sensory neurons together
Is short and most and multipolar
230
Types of inter neurons
In cerebellum: purkinje cells, stelate cells, basket cells
In cerebrum (cerebral cortex): pyramidal cells
231
Glial cells in CNS
- Astrocytes
- Ependymal cells
- Microglia
- Oligodendrocytes
232
Astrocytes
Most abundant cells that are star-shaped
Helps reuptake protein back to cell body (retrograde), recycles and reuses neurotransmitter, part of blood-brain barrier, produces molecules necessary for growth
233
Blood-brain barrier
Prevents the passage of large macromolecules and pathogens between the blood and brain
-Made of Astrocytes and endothelial cells lining the blood
234
Microglia
Smallest cell and least abundant
Derived from monocytes and are the macro phases of CNS
Found only in areas of inflammation
235
Ependymal cells
Line the central canal of spinal chord and brain
Have cilia
Produce cerebrospinal fluid and help circulate it
236
Oligodendrocytes
Produces the myelin sheath in CNS.
Wraps around many axons
237
Glial cells in PNS
- Satellite cells
| - Schwann cells
238
Satellite cells
Surround neuron cell bodies for support
239
Schwann cells
Wraps around axons to form myelin sheath. One cell for one axon
240
Nerves
Composed of only axons without dendrites and cell body
Carry sensory or motor fibers
241
3 connective tissues that surround neurons
- Epineurium
- Perineurium
- Endoneurium
242
Epineurium
Thick connective tissue that surrounds fascicles
243
Perimysium
Dense irregular connective tissue that surrounds a fascicle
244
Endoneirium
Thin connective tissue that surround each neuron after the myelin sheath
245
Myelin sheath
Forms an insulating layer and prevents leakage of the electrical current
246
Cell bodies of sympathetic ganglia
Smaller than sensory neurons and have satellite cells surrounding them
247
Repair of neurons
When neuron is damaged, nucleus will go to the periphery and Schwann cells will proliferate to put the two halves back together
If this doesn’t happen, leads to traumatic neuroma
