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Histo Exam CU > Histo Exam 2 > Flashcards

Histo Exam 2 Flashcards

1
Q

Chondroprogenitor cells

A

Mesenchyme progenitor unipotent stem cells that differentiate into chondroblasts as part of appositional growth

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2
Q

Chondroblasts

A

An immature cell that actively produce the components of the extracellular matrix and are involved in appositional growth.

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3
Q

Chondrocyte

A

Are cells that secrete the extracellular matrix on cartilage and becomes embedded in it. Derived from chondroblasts, mature and involved in nourishment and maintenance of the cartilage. Involved in interstitial growth of cartilage.

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4
Q

Perichondrium

A

DRCT covers the outer surface of most cartilage types. Contains and outer fibrous layer made of fibroblasts and capillaries. and an inner cellular layer that contains chondroporogenitor cells

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5
Q

Blood supply of cartilage

A

Avascular. Blood vessels found in DRCT of perichondrium and nutrients must diffuse through ground substance

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6
Q

Lacunae

A

Potential spaces surrounding the cells within the matrix in which they chondrocyte/chondroblast resides.

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7
Q

Isogenous groups

A

Clusters of recently mitotic chondrocytes. Reflects recent mitosis of chondrocytes and interstitial growth

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8
Q

What fiber type is present in all cartilage

A

Type II

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9
Q

Ground substance

A

Non fibrous proteins. Hyaluronic acid, proteoglycans, glycoproteins. High amounts of ground substance draws in high amounts of water to provide turgor

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10
Q

Does supportive CT or CT proper have more ground substance

A

Supportive CT like bone and cartilage has more GS

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11
Q

Territorial matrix

A

Region immediately surrounding lacunae with newly synthesized matrix proteins. Contains a higher amount of ECM.

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12
Q

Inter-territorial matrix

A

A region of older cartilage matrix proteins located between the lacunae. Stains lighter than territorial matrix.

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13
Q

What are the three types of cartilage

A

Hyaline, elastic, and fibrocartilage.

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14
Q

Hyaline cartilage

A

Type II collagen, perichondrium usually present but not on articular surface of synovial joints. Resists compressive forces/flexible support of respiratory system. Provides smooth low friction surface. Located in costal cartilage, trachea, nasal cartilage, articular joint surfaces.

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15
Q

What provides nutrients to synovial joints

A

The synovial membrane that produces the synovial fluid since there is no perichondrium.

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16
Q

Elastic cartilage

A

Always has a perichondrium, provides flexible support and elasticity and found in the pinna, external auditory canal, epiglottis, larynx

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17
Q

Fibrocartilage

A

Type I and II collagen, never has a perichondrium. Type I collagen fibers between rows of cells. Always associated with DRCT and provides tensile strength and resilience for DRCT. Provides protection against compressive, tearing and shearing forces, cushioning, resists deformation and shock absorption. Intervertebral discs (annulus fibrosus), meniscus of knee, covers articulating surface of condyle, articular disc.

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18
Q

Interstitial growth

A

Mitotic division of existing chondrocytes; a single chondrocyte divides to form identical cell clusters within ECM matrix. Interstitial growth diminishes following maturation during early adulthood.

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19
Q

Appositional growth

A

Surface growth—new cartilage stem cells divide and differentiate into chondroblasts along surface. Any type of cartilage that lacks a perichondrium will be unable to undergo appositional growth.

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20
Q

Cartilage repair

A

Limited by vascular supply, limited by age. Higher repair capacity for cartilage containing a perichondrium due to stem cell source. Articular cartilage and fibrocartilage typically requires surgical intervention.

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21
Q

Osteoarthritis

A

Most common chronic non-inflammatory disease caused by progressive loss of cartilage on the articular surface of bones.

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22
Q

Rheumatoid arthritis

A

RA is an autoimmune disease caused by antibodies destroying synovial membranes and leading to chronic inflammation.

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23
Q

What is the histological key difference that distinguishes TMJ from articular knee joint?

A

1) the type of cartilage
2)perichondrium

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24
Q

Which ECM components in TMJ allows the cartilage to function as a shock absorber and resist compression?

A

Type I/II and proteoglycans

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25
Q

What type of cartilages is in the TMJ

A

Fibrocartilage

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26
Q

Osteoprogenitor cell

A

Small flat shaped stem cells capable of mitosis that differentiate into osteoblasts. Located in the CT covering bone surfaces (periosteum). Unipotent

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27
Q

Osteoblasts

A

Located on periphery/free edge of bone. Differentiate from osteoprogenitor cells. Do not undergo mitosis and are nullipotent. Responsible for synthesis of unmineralized bone ECM. Regulate deposition of inorganic minerals that form hydroxyapatite.

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28
Q

Osteocytes

A

Cells entrapped within mineralized bone matrix; reside in lacunae; contain cytoplasmic processes that connect to adjacent osteocytes via gap junctions. Do not undergo mitosis and are nullipotent.

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29
Q

Osteoclasts

A

Large multinucleated cells found on edge of mineralized bone matrix. Don’t undergo mitosis and are nullipotent. Howships lacunae represents sight of active resorption.

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30
Q

Organic osteoid

A

Contributes 30% of total ECM. Of that 30%, 90% is type I collagen fibers. Non-fibrous proteins is about 10%. Contains a higher amount of fibers than GS when compared to ECM cartilage. The collagen fibers provide a scaffold and controls the extent of mineralization.

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31
Q

Inorganic matrix (of bone)

A

Hydroxyapatite (Ca10(PO4)6(OH2)) develops from inorganic calcium and phosphate ions. Bone is 70% inorganic. It is mineralized!

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32
Q

Mineralization

A

1-deposit bone organic matrix (osteoid)
2-mineralize matrix by deposition of inorganic matrix

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33
Q

What does mineralization depend on

A

Presence of Ca2+ ions and phosphate ions. Calcium and phosphate in the blood are hormonal regulated and depend on vitamin D.

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34
Q

Failure to mineralize results in what

A

A decrease in percentage of inorganic matrix=soft bones.

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35
Q

Long bones

A

Cylinder like shape that is longer than the bone is wide. Function to leverage. Femur, tibia, fibula, metatarsals, humerus, ulna, radius, phalanges.

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36
Q

Short bones

A

Cube like shape, approximately equal in length, width, and thickness. Provide stability, support, while allowing for smooth motion. Carpals (wrist), tarsals (ankle/foot).

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37
Q

Flat bones

A

Thin and curved. Points of attachment for muscles, protectors of internal organs. Sternum, ribs, scapulae, cranial bones, facial bones.

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38
Q

Irregular bones

A

Complex shape, protect internal organs, vertebrae, pelvis, sacrum, base of skull.

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39
Q

Sesamoid bones

A

Small and round, embedded in tendons. Protect tendons from compressive force. Patellae, pisiform.

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40
Q

Periosteum

A

DRCT covers outer compact bone

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41
Q

Endosteum

A

LCT lined medullary cavity and trabecular bone surfaces

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42
Q

Marrow cavity

A

Filled with yellow marrow—mainly adipose in adult long bones

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43
Q

Diaphysis

A

Shaft of lone bone. Comprised mainly of compact bone in walls, sparse trabecular bone, large medullary cavity. Provides structural support without increased weight. This is the first region ossified—prior to birth.

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44
Q

Epiphysis

A

Proximal and distal articulating ends of long bone—orientation of trabeculae direct force to shaft. Appears as expanded rounded end (head) and contains a high amount of trabecular bone in adults. Covered on end with articular cartilage, no perichondrium. Second region to ossify during childhood.

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45
Q

Metaphysis

A

Region between shaft and head (neck). In adult, contains high amount of trabecular bone and epiphyseal line—remnant of EGP and compact bone surface.

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46
Q

Physis

A

Epiphyseal growth plate—area of hyaline cartilage present during childhood and adolescence. Hyaline cartilage allows for bone elongation through interstitial growth of cartilage. Last region to ossify

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47
Q

Epiphyseal line

A

Mineralized growth plate

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48
Q

Two layers of compact bone

A

External table- outer thicker layer of compact bone
Internal table- inner more thin layer of compact bone

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49
Q

Periosteum

A

DRCT, covers both surfaces of compact bone

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50
Q

Endosteum

A

LCT, lines medullary cavity and trabecular surfaces

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51
Q

Marrow cavity

A

Found between spaces of the trabecular bone—filled with red marrow

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52
Q

What structures are not present in flat bones

A

Epiphysis, diaphysis, metaphysis

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53
Q

Structures within the periosteum and function of it

A

Site of tendon and ligament attachment and contains blood vessels, osteoprogenitor cells, and fibroblasts.

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54
Q

What type of tissue is the periosteum

A

Dense regular connective tissue

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55
Q

What type of tissue is the endosteum

A

Loose connective tissue

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56
Q

Features of compact bone

A

Located in outer cortex, appears as dense area of bone, comprises 80% of total bone mass. Comprised of numerous osteons surrounded by concentric lamellar appearance

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57
Q

Features of trabecular bone

A

Comprises 20% of total bone mass, located in center region of all bones, marrow cavity is located within the spaces of bone, has rod like lamellar arrangement.

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58
Q

Osteons

A

Represent osteocytes/mineralized tissue arranged in circular pattern around neurovascular channel (HC). They are the the structural units associated with compact bone

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59
Q

Haversian canal

A

Neurovascular channel oriented in the long axis of bone lined with osteoprogenitor cells/osteoblasts. BV in this canal that provides nutrients.

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60
Q

Lacunae

A

Space in bone matrix; contain osteocyte cell body.

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61
Q

Cannaliculi

A

Interconnecting canals in bone which contain the osteocyte dendritic processes. They function to connect osteocytes in adjacent lacunae to each other and connects the osteocytes to the Haversian canals. Cell processes of osteocytes communicate via gap junctions.

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62
Q

Volkmann’s canal

A

Neurovascular canals that interconnect Haversian canals. Oriented perpendicular to Haversian canal.

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63
Q

Extraosteonal lamellae

A

Parallel layers of outer cortical bone located just deep to the periosteum.

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64
Q

Inner circumferential lamellae

A

Dense inner cortical bone located around the circumference of the marrow cavity.

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65
Q

Interstitial lamella

A

Region between osteons—remnants of remodeling

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66
Q

What can you see in decalcified vs dry ground prep

A

In decalcified prep you see living tissue in a dry ground only see inorganic material.

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67
Q

What is the arrangement of trabecular bone

A

Parallel lamellar arrangement

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68
Q

What type of bone is typically affected first by Ca++ homeostasis

A

Trabecular/spongy bone because it has less mass and more surface area

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69
Q

Trabeculae

A

Bony plates aligned along lines of mechanical stress

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70
Q

What structure is not seen in spongy bone

A

Osteons

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71
Q

Intramembranous path

A

Direct ossification associated with skull bones, flat bones of face, scapula and clavicle. Osteoprogenitor—>osteoblast—>deposit ECM matrix which surrounds osteocytes.
Bone appears woven and then remodels into compact and spongy bone.

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72
Q

Endochondral path

A

Indirect ossification that most long bones, short bones and irregular bones undergo.
Chondroprogenitor—>chondroblast—>chondrocyte—>hyaline—>replaced by woven bone—>adult compact and spongy

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73
Q

What cells secrete the osteoid and what happens to those cells after

A

Osteoblasts secrete the osteoid and after it is mineralized the trapped osteoblasts become osteocytes.

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74
Q

In endochondral ossification what product do you start with

A

Start with hyaline cartilage before birth. Eventually becomes epiphyseal growth plate until age 20 or so and then becomes epiphyseal line in adult long bones.

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75
Q

What structure allows long bones to continue to grow during childhood and adolescence

A

Epiphyseal growth plate

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76
Q

What does premature closure/ossification of the EGP yield

A

Short stature

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77
Q

Primary ossification site

A

Diaphysis

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78
Q

Secondary ossification site

A

Epiphysis

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79
Q

Does all hyaline cartilage calcify at some point during endochondral ossification

A

No, a layer of hyaline cartilage remains on articular joint surfaces and is called articular cartilage

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80
Q

Epiphyseal growth plate

A

A region of hyaline cartilage that allows for developing long bones to grow in length along the long axis of the bone

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81
Q

How is growth along the longitudinal axis is the EGP achieved

A

Mitosis of cartilage cells within cartilage matrix

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82
Q

What controls the closure of the growth plate

A

Sex hormones

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83
Q

Achondroplasia

A

Genetic disease causing short limbed dwarfism due to failure of cartilage to grow. This only affects bones that undergo endochondral ossification.

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84
Q

Resting zone

A

Random arrangement of inactive chondroblast

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85
Q

Zone of proliferation

A

Mitotic activity of chondrocytes—rows of isogenic groups

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86
Q

Zone of maturation/hypertrophy

A

Enlarged lacunae chondrocytes mature; no longer mitotic; secrete alkaline phosphatase that facilitate calcification of cartilage matrix.

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87
Q

Zone of calcified cartilage (calcification)

A

Large empty lacunae b/c calcification of cartilage matrix lead to apoptosis of chondrocytes

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88
Q

Zone of ossification/mineralization

A

Osteoblasts continue to deposit bone matrix on calcified cartilage and mineralize bone matrix—> immature (woven)bone

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89
Q

What will always be the product of ossification

A

Woven bone

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90
Q

Primary (woven) bone

A

First bone to appear during development and repair, rapidly deposited, irregular appearance of type I collagen, high number of osteocytes, low mineral content/unmineralized, appears as an open loose spongy arrangement of bone.

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91
Q

Secondary (adult lamellar) bone

A

Found in adult bone following repair/remodeling, layered arrangement of collagen around vascular channel, cells in lacunae deposited in regular intervals, youngest cells closest to vascular channels, high mineral content, collagen and mineralized matrix organized parallel to each other within lamella and collagen fibers organized along lines of stress.

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92
Q

Two structural arrangements of adult lamellar bone

A

Compact and trabecular

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93
Q

What does all bone tissue begin and end as?

A

Begins as primary woven bone and will be replaced by secondary adult lamellar bone.

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94
Q

Appositional growth

A

Bone increases in diameter/thickness due to surface growth along periosteum and endosteal surfaces

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95
Q

Interstitial growth

A

Only occurs in regions of cartilage of the growth plate. Chondrocytes divide and it allows developing bones to increase in length along the long axis

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96
Q

Histological appearance of woven bone

A

Irregular and random arrangement of cells, random collagen fibers, lightly calcified, high in cell number and the bone appears loosely arranged in spicules

97
Q

Adult lamellar bone histological appearance

A

Parallel bundles of collage in thin layers called lamellae, regularly spaced cells that are heavily calcified.

98
Q

Mature compact (cortical) bone histological appearance

A

Parallel lamellae arranged, circumferential lamella densely packed with concentric lamellae, interstitial lamellae

99
Q

Mature (spongy) bone histological appearance

A

Parallel lamellae are interconnected as thin spicules or plates known as trabeculae which are each covered by endosteum.

100
Q

Locations of woven bone

A

Developing and growing bones, first type of bone deposited in fracture repair, forms the hard callus of bone fractures.

101
Q

Adult lamellar bone locations

A

All normal regions of adult bone; deposited during bone remodeling of bone fracture.

102
Q

Locations of compact bone

A

Thick outer region of bones beneath the periosteum. Wall of diaphysis, external/internal tables

103
Q

Locations of trabecular bone

A

Inner region of bones interspersed between marrow cavities; long bone it is in the epiphysis and metaphysis and in flat bones in the dipole.

104
Q

Bone modeling/remodeling occurs when

A

During periods of growth and at points of mechanical stress or following repair. It functions to maintain bone mass or change existing shape

105
Q

Wolffs law

A

every change in bone function is followed by changes in the internal and external structural architecture

106
Q

Environmental stimuli that trigger remodeling/modeling

A

Hormones/growth factors, maintenance of ion homeostasis, mechanical load/force/stress, injury or trauma

107
Q

Possible outcomes of stimuli that trigger bone modeling and remodeling

A

Bone resorption or bone deposition

108
Q

Bone resorption

A

Osteoblasts recruit osteoclasts to resorb bone

109
Q

Bone deposition

A

Osteoblasts deposit bone

110
Q

What runs at various angles and runs along lines of stress

A

Trabeculae and they transmit the stress to cortical bone

111
Q

Where does remodeling occur

A

On the same same surface because remodeling is a balance between deposition and resorption

112
Q

Where does modeling occur

A

Modeling occurs on a different surface to increase bone mass and to change shape of bone

113
Q

Phases of modeling/remodeling

A

Activation-recruitment of osteoblasts
Resorption-degradation of mineralized matrix by osteoclasts via acid phosphatase enzymes
Reversal-cessation of resorption/osteoclasts disappear.
Deposition-OB deposit new bone matrix at site of resorption;leads to reversal line
Resting-bone formation ceases and OB inactive

114
Q

What happens to bones when they do not undergo strain

A

They can undergo disuse atrophy

115
Q

Repair

A

Bone is a stable cell population containing stem cells that may be induced to renew and differentiate

116
Q

What bones undergo repair

A

Flat and long

117
Q

Direct repair

A

Occurs if ends stabilized and/or close together or small gap—uses intramembranous ossification

118
Q

Indirect repair

A

Mechanism by most fracture repair—uses cartilaginous callus follows. Follows steps of endochondral ossification due to large gap between fractured ends

119
Q

Four major stages of indirect fracture repair

A

Hematoma formation/inflammation
Fibrocartilaginous callus formation
Bony callus formation
Remodeling of bony callus, deposition of lamellar bone

*no scar in bone since bone is replaced w new bone

120
Q

Anatomical divisions of the nervous system

A

CNS and PNS

121
Q

Functional divisions of the nervous system

A

Somatic nervous system and autonomic nervous system

122
Q

Divisions of the autonomic NS

A

Sympathetic and parasympathetic

123
Q

How do neurons communicate

A

Synapses

124
Q

Neurons

A

Structural and functional cell that is exciteable and receives, processes and transmits info rapidly via electrochemical signals called action potentials

125
Q

Neuroglial cells (glial cells)

A

Supportive cells that provides structural integrity and functional support to allow normal nerve function

126
Q

Key features of glial cells

A

No synapses between cells, function to maintain ionic environment, myelinate nerve fibers, phagocytize debris and they are located in CNS and PNS

127
Q

What germ layer gives rise to the CNS

A

Neural tube

128
Q

Development of CNS

A

Neuroepithelium rapidly proliferate and give rise to neurons and glial cells of the CNS.

129
Q

Neurons and glial cells of the CNS

A

Motor neurons, inter neurons, Astrocytes, oligodendrocytes, and ependymal cells

130
Q

Development of PNS

A

NC cells arise from the lateral edge of the neural plate and give rise to neurons and glial cells of PNS

131
Q

Neurons of the PNS

A

Pseudounipolar, postganglionic sympathetic (motor), postganglionic parasympathetic (motor)

132
Q

Where are pseudounipolar neurons located and what function do they serve

A

They are in the DRG and cranial nerve ganglia. Function to receive info from skin, joints, muscle and other regions about touch, pressure, temp, pain, stretch, proprioception

133
Q

Where are postganglionic sympathetic neurons located

A

Paravertebral and prevertebral ganglia

134
Q

Postganglionic parasympathetic neuron locations

A

Enteric ganglia

135
Q

Glial cells of the PNS

A

Schwann cells and satellite cells

136
Q

Flow of information of a neuron

A

Dendrites, cell body, axon, and terminus then to next neuron or effector tissue (ex:muscle)

137
Q

Dendrites

A

Receptor processes, 1 or more branch extensively in a tree like appearance and are unmyelinated. They receive signals from neurons via a synapse and convey it to the cell body

138
Q

What determines morphological identification of a neuron

A

Number and shape of dendrites

139
Q

Dendritic spines

A

Bud like extensions at the site of synapse and they increase area for synaptic contact

140
Q

Contents of a dendrite

A

Organelles, nissl, and cytoskeletal elements

141
Q

Contents of a cell body

A

Nucleus, cytoplasm, axon hillock

142
Q

What organelle is responsible for neurotransmitter synthesis

A

rER

143
Q

What organelle of the cell body lack Nissl substance

A

Axon hillock and that’s what distinguishes it form dendrites

144
Q

Axon

A

Conveys information away from one cell body to another to another or an effector cell. Has no organelles but the plasma membrane is specialized for impulse conduction

145
Q

Initial segment

A

Between axon hillock and myelin sheath and its the site of action potential generation

146
Q

What cells myelinate axons

A

Schwann cells and oligodendrocytes

147
Q

Synapses

A

Functional points of contact that facilitates communication between neurons or neurons and effector cells. Point of information transfer

148
Q

Morphological classifications of synapses

A

Axodendritic, axosomatic, axoaxonic

149
Q

What is the endpoint of an axon

A

Terminal arbor

150
Q

Terminal bouton

A

Functional point of contact containing mitochondria and neurotransmitter containing vesicles

151
Q

Electrical action potentials

A

Occurs through gap junctions, its faster based on direct flow of ions between adjacent cells and it is bidirectional. These are limited in number in adult humans.

152
Q

Cells that utilize electrical AP

A

Astrocytes, smooth muscle, cardiac and neuroendocrine cells

153
Q

Chemical AP

A

Occurs through neurotransmitter chemicals, most common, unidirectional, can be inhibitory or excitatory

154
Q

What determines if an AP is excitatory or inhibitory

A

Type of NT, amount of NT, type of receptor on effector cells and the amount of receptors expressed

155
Q

Steps involved of chemical synapse

A

Release of NT from presynaptic membrane and diffusion across synaptic cleft
NT binding to specific receptors on postsynaptic membrane that stimulates or inhibits AP generation
An AP on postsynaptic membrane elicits response isn’t he postsynaptic cell
Enzymatic degradation or clearing of NT terminates the signal

156
Q

Functional adaptation of axonal transport

A

Neuron secretory zone is far from cell body. Neurons are critically dependent on highly regulated bi-directional movement of molecules.

157
Q

Anterograde transport

A

Movement of molecules/organelles away from the cell body to the axon terminals via kinesin. Transport in synthesized NT within vesicles to synaptic terminal

158
Q

Retrograde transfer

A

Movement of materials from axon terminals to the cell body by Dynein. Recycle synaptic vesicles

159
Q

Clinical significance of retro and anterograde pathways

A

They are important pathways for some neurotropic viruses (herpes simplex virus, polio,rabies) to invade the PNS or CNS

160
Q

How to classify a neuron

A

Based on number of processes extending from cell body

161
Q

Classification of neurons

A

Based on morphology, function, location, pathway and NT specificity

162
Q

Multipolar neurons

A

One axon, and two or more dendrites. They have cell bodies present in the brain, spinal cord and autonomic ganglia. All motor neurons and interneurons.

163
Q

Functions of multipolar neurons

A

Transmitting somatic and visceral motor impulses from brain to effector organs. Multipolar neurons perform the majority of cognitive processes

164
Q

Bipolar neurons

A

Very rare. Round or oval cell body, one axon and one dendrite, associated with receptors for special senses. Found in sense organs like retina, olfactory epithelium

165
Q

Pseudounipolar neurons

A

Spherical cell body, one axon that divides close to cell body into two long axonal branches. One to periphery and other to CNS. Develops from bipolar neurons and majority are sensory neurons close to CNS

166
Q

What germ layer gives rise to Pseudounipolar neurons

A

neural crest cells

167
Q

Where are the cell bodies of pseudounipolar neurons located

A

Dorsal root ganglia and cranial nerve ganglia

168
Q

Function of Pseudounipolar neurons

A

Sensory neurons both visceral and somatic of the PNS. Receives information from skin, joints, muscles and other body regions

169
Q

Somatic sensory

A

Mostly conscious perception and examples influe touch, pain, pressure, vibration, temperature, and proprioception from skin body wall and limbs.

170
Q

Visceral sensory

A

Mostly unconscious perception. Very few examples in the body such as aortic and carotid bodies. Sense CO2 levels, blood pressure, gut distension from internal organs

171
Q

Special sensory

A

Smell, sight, balance, hearing

172
Q

Motor neurons

A

Convey impulses from CNS or ganglia to effector cells. Also called efferent.

173
Q

Somatic motor

A

Send voluntary impulses to skeletal muscles. Consciously controlled and cell bodies are located in the ventral horn spinal cord (CNS)

174
Q

Visceral motor

A

Transmits involuntary impulses to smooth muscle and cardiac conducting cells and glands. Preganglionic in the lateral horn of SC and postganglionic (autonomic ganglion) located in the PNS

175
Q

Interneurons

A

Integrative neurons and make up 99% of all neurons. Form a communicating and integrating network between sensory and motor neurons. Cell body and all processes located entirely within the CNS. They play a very important role in reflex arcs.

176
Q

Hermetic gingivostomatitis

A

Cold sores or fever blisters that are reoccurring lesions within or around the lips of the oral cavity. The trigeminal sensory neurons become the target of the virus and the virus remains dormant until triggered via stress or illness. Uses retrograde transport.

177
Q

Neuroglia

A

Do not propagate AP’s, only nuclei of glial cells are seen in routine histological sections, functionally interdependent with neurons.

178
Q

Neuroglia function

A

Physically support/protection for neurons
Insulation for nerve cell bodies and processes that facilitates rapid transmission of nerve impulses
Repair of neuronal injury
Regulation of internal fluid environment of CNS
Clearance of NT form synaptic cleft
Metabolic exchange between vascular system and neurons

179
Q

CNS glia

A

Atrocytes, oligodendrocytes, ependymal cells, microglia

180
Q

PNS glia

A

Satellite cells, Schwann cells, macrophages/phagocytosis cells

181
Q

Two types of astrocytes

A

Protoplasmic and fibrous

182
Q

Protoplasmic astrocytes

A

Prevalent in gray matter, numerous short branching processes

183
Q

Fibrous astrocytes

A

Prevalent in white matter and have fewer processes that are relatively straight

184
Q

End feet

A

Astrocytes processes end expansions. Cover myelinated axons at nodes of ranvier and at synapse. Line subpial surface of CNS forming glia limitans. Lines BV’s forming blood brain barrier.

185
Q

Blood brain barrier

A

Highly selective, formed by tight junction of endothelium surrounded by a basement membrane and astrocytes end feet.

186
Q

Function of astrocytes

A

Modulate ionic composition by clearing K+ following action potential. Remove NT from synaptic, move metabolites and waste to and from neurons.

187
Q

Ependymal cells

A

Epithelial like lining of ventricles of brain and spinal(central) canal. Single layer of cuboidal columnar wit no basement membrane. Modified ependymal cells are associated with capillaries that produce CSF.

188
Q

Apical surface modifications of ependymal cells

A

Cilia and microvilli. Cilia circulates CSF and microvilli absorb it.

189
Q

What structure produces CSF

A

Choroid plexus

190
Q

Microglia

A

Phagocytosis cells derived from granulocyte/monocyte progenitors. Small elongated nuclei with short twisted processes.

191
Q

Satellite cells

A

Cells surrounding neuronal cell bodies in ganglia. They maintain micro environment around neuronal cell bodies in ganglia, providing insulation and facilities metabolic exchange.

192
Q

Satellite cells of DRG

A

No synapses, pseudounipolar, arranged in clusters and myelinated. Satellite cells completely surround cell bodies

193
Q

Satellite cells around parasympathetic and sympathetic ganglia

A

Satellite cell incompletely surrounds cell bodies.

194
Q

Schwann cells

A

Produces and maintains myelin sheath in PNS, supports one myelinated and many unmyelinated axons. AIDS in cleaning up debris and axonal regeneration. Basement membrane is present.

195
Q

Myelin sheath

A

Insulates axons and concentrates ion channels at nodes of ranvier. Results in increased nerve conduction. Absent at the axon hillock, nodes of ranvier and axon terminals.

196
Q

Myelin formation

A

Schwann cell plasma membrane surrounds axon and wraps around axon in a spiraling motion forming multiple layers. Cytoplasm in squeezed out of inner layers and stabilized by myelin specific proteins.

197
Q

What permits transport in myelin formation

A

Schmidt-lantern clefts

198
Q

Nodes of ranvier

A

Represents junction between two adjacent Schwann cells. Site of concentrated ion channels that facilitate saltatory conduction.

199
Q

Oligodendrocyte

A

Produces and maintains myelin in CNS, gives off multiple tongue-like processes that can myelinate one or many nearby axons. They express myelin specific proteins to maintain myelin layers. Aligned in rows.

200
Q

Gillian-Barre syndrome

A

Acute demyelination disease of the PNS considered an autoimmune disease following viral or bacterial infection, immune system attacks the myelin specific proteins of Schwann cells.

201
Q

Multiple sclerosis

A

Chronic demyelinating disease of the CNS. Immune system attack the myelin specific proteins of oligodendrocytes.

202
Q

Functional overview of CNS

A

Integrate, process and coordinate sensory input. Execute motor responses. Regulation of homeostatic mechanism. Execute reflexes from the body and organs.

203
Q

Anatomical divisions of the CNS

A

Grey and white matter

204
Q

Gray matter

A

Contains neuronal cell bodies, axons, dendrites and CNS glia. Site of synaps. Outmost covering of the cerebral cortex and it contains nuclei.

205
Q

Nuclei

A

Islands or clusters of grey matter within the cerebrum, cerebellum and brain stem that are functionally and spatially related neuronal cell bodies.

206
Q

White matter

A

Forms inner core of CNS. Contains axons, CNS glia, and BV’s. Contains tracts or fasiculi.

207
Q

Tracts

A

Bundle of parallel axons that form motor and sensory tracts and connect neighboring and distant nuclei. They are functionally related.

208
Q

Spinal cord

A

Made of grey and white matter.

209
Q

Somatic motor neurons

A

Terminate in skeletal muscle in the body and have cell bodies in the ventral/anterior horn of the spinal cord.

210
Q

Visceral motor

A

Relay info to ganglion neurons in the PNS which then terminate on glands, smooth and cardiac muscle, and BV’s. Cell body is located in the lateral horn of the SC

211
Q

Integrative/relay or interneurons

A

Form a chain of interconnecting neurons from spinal cord to cerebral cortex. Cell body in dorsal horn of spinal cord.

212
Q

Organization of PNS

A

Consists of peripheral nerves with specialized nerve endings and ganglia (motor and sensory) containing neuronal cell bodies outside the CNS.

213
Q

Functional divisions of the PNS

A

Somatic nervous system and autonomic nervous system.

214
Q

Somatic nervous system

A

Provides sensory and motor innervation to all parts of the body except cardiac muscle, smooth muscle and glands. Sensory division transmits touch, pain, temp. Motor division only innervates skeletal muscle.

215
Q

Autonomic nervous system

A

Associated with involuntary visceral motor and accompanying sensory function to glands and organs. Sympathetic division is accompanied by visceral pain fibers and parasympathetic is accompanied by visceral afferent reflex fibers.

216
Q

Peripheral nerve

A

Consists of nerve fibers that carry sensory and motor information between the organs and tissues of the body and brain/spinal cord.

217
Q

Peripheral nerve, nerve fiber

A

Consists of axon, myelin adn Schwann cell held together by CT. peripheral nerve fibers can be myelinated or unmyelinated. Consists of spinal, cranial and named peripheral nerves.

218
Q

Endoneurium

A

Loose CT that surrounds nerve fibers. Collagen type III fibrils interlink adjacent nerve fibers into fascicles.

219
Q

Perineurium

A

Squamous perineurial cells ensheath fascicles forming 2-6 layers of specialized CT.

220
Q

What creates the blood-nerve barrier

A

Perineurial cell barrier

221
Q

Blood nerve barrier

A

An active diffusion barrier between capillaries and nerve fibers.

222
Q

Epineurium

A

Dense irregular CT that surrounds and binds nerve fascicles into a common nerve. Primarily type I collagen.

223
Q

Sympathetic division of autonomic NS function

A

Energy expending/fight or flight

224
Q

Parasympathetic division of autonomic NS function

A

Energy conserving/rest and digest

225
Q

What neurotransmitters are used in sympathetic vs parasympathetic neurons.

A

Sympathetic- acetylcholine, norepinephrine, epinephrine
Parasympathetic-acetylcholine

226
Q

Another name for sympathetic division

A

Thoracolumbar

227
Q

Another name for parasympathetic division

A

Craniosacral

228
Q

Pre and post ganglionic lengths of sympathetic neurons

A

Pre is short because ganglia are close to SC and the post is long.

229
Q

Choroid plexus

A

Produces cerebrospinal fluid

230
Q

What kind of capillaries are in the choroid plexus

A

Fenestrated capillaries

231
Q

What maintains the blood CSF barrier and how

A

Ependymal cells via tight junctions

232
Q

What cells secrete CSF

A

Ependymal cells through selective active transport mechanism

233
Q

Meninges

A

Membranous CT coverings of the CNS. They protect the brain and spinal cord, provide supportive framework for vessels and enclose fluid filled cavities (subarachnoid space)

234
Q

Dura mater

A

DRCT composed of elongated fibroblasts and high concentration of collagen. Outer most layer

235
Q

Arachnoid mater

A

Large fibroblasts closely Apposed and attached by tight junctions. Devoid of collagen, arachnoid trabeculae bridge arachnoid space. Middle layer.

236
Q

Pia mater

A

Composed of epithelium, collagen type I, elastic and reticular fibers. Directly covers the surface of the brain and spinal cord.

237
Q

What structures do you pass through when doing a lumbar puncture

A

Skin, subcutaneous, supraspinous ligament, interspinous ligament, ligamentous flavum, epidural space, dura mater, arachnoid mater, subarachnoid space to CSF

238
Q

Fibrocartilage always lacks a perichondrium except in one joint, what is it?

A

TMJ. It has a perichondrium and a Fibrocartilage covering as opposed to hyaline

Histo Exam CU (3 decks)

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