Histology - 514-4,5,6,7 Flashcards
What does cortical mean?
cortex - around the outside
What does the PDL connect?
The cementum around the tooth to the alveolar bone
What type of collagen is the PDL composed of?
Type I, III, VII
What are the most abundant cells in the PDL?
Fibroblasts
The PDL alveolar attachment is equivalent to what structure in bone?
Periosteum
What cells form new bone after tooth extraction?
PDL fibroblasts > osteoblasts
Do Sharpey’s fibers blend into cementum?
Yes
hard to see on slide
What is the term for alveolar bone directly lining a tooth?
Bundle Bone
refers to Sharpey’s Fibers
What nerve innervates the PDL?
Trigeminal V
What is very tightly related to nerve endings in the PDL?
Collagen fibers
What type of fibers are oxytalan and what do they do?
Elastic.
Absorptive and keep vasculature open in PDL
Name the 5 principal fiber types of the PDL
- Alveolar Crest Group
- Horizontal Group
- Oblique Group
- Apical Group
- Interradicular Group
What is the additional fiber ligament that connects teeth to bone and has “memory”?
Transseptal ligament
Transseptal fibers are part of…
The GL (gingival ligament)
Where is the GL found?
Above the PDL in lamina propria
What are the five fiber bundles found in the GL?
Dentogingival, alveologingival, circular, dentoperiosteal, transseptal
What are the 3 general categories of tooth movement?
Preeruptive, eruptive, posteruptive
What are gubernacular canals?
cords of fibrous tissue creating a path for eruption.
Why is root formation not a cause of eruption?
Think tree
Why does alveolar bone remodeling not explain tooth eruption?
only explains how pathway was cleared
What is the best (however incomplete) model for tooth eruption?
PDL formation as motive force
What side does most of the resorption of deciduous teeth occur on?
Lingual
What side do permanent teeth develop relative to deciduous?
Lingual
What happens when a permanent tooth contacts a deciduous tooth from below?
Resorption happens at the root end of the deciduous tooth
What prefix is everything tooth?
Odonto (as opposed to osteo)
T/F
Odontoclasts are histologically identical to osteoclasts
True
What are 3 reasons for posteruptive tooth movement?
accommodation for growth (age 14-18)
compensation for continued occlusal wear
accommodation for inter proximal wear (mesial drift)
What undergoes hyalinization on the compression side of orthodontic tooth movement?
hyalinization (loss of cells in the PDL)
If forces are too heavy in tooth movement, what occurs?
Odontoclast resorption of dentin.
Is pressure from erupting permanent tooth necessary for deciduous tooth loss?
No, although it does cause resorption on the side being resorbed.
Define synostosis
Bony joint - immovable, and fused by osseous tissue
think left and right mandible
Name four types of joints.
Bony
Fibrous
Cartilaginous
Synovial
The left and right mandible are separated by what kind of joint?
Synostoses / Bony
Name 3 types of fibrous joints.
serrate sutures (cranial)
squamous sutures
plane/butt sutures (palate)
Attachment of a tooth to its socket is a joint called a,
gomphosis
example of sydesmosis
tibia to fibula (movable and fibrous)
Example of synchondrosis
hyaline cartilage from sternum to ribs.
What is an example of a symphysis (cartilaginous joint)?
Pubic symphysis
Intervertebral discs
What are the most freely moveable joints?
Synovial
What articulation makes up the TMJ?
mandibular condyle with the mandibular fossa (glenoid fossa) of the temporal bone
Is there any cartilage on cartilage action in the TMJ?
No - because of articular disk
What is articular cartilage composed of?
coarse collagen fibers (dense fibrous connective tissue)
What is TMJ syndrome caused by?
malocclusion, injury, arthritis
What is a broad term for joint pain/inflammation?
arthritis
In which type of arthritis is articular cartilage worn away?
osteoarthritis
What type of arthritis is an autoimmune response?
Rheumatoid
cells attack joint as if it was a pathogen and degrades cartilage
Is glucosamine/chondroitin an effective means to treat osteoarthritis?
No
Why are tendon sheaths in the hands/feet unique?
They wrap tendons in synovial fluid.
What is a bursa?
saclike extension of a joint capsule that lubricates nearby tendons (think shoulder)
How many muscles in the human body?
About 600
What percentage of body heat is produced by muscle activity?
85%
The _______ blends with tendon to lend more structural integrity.
Periosteum
The dense irregular connective tissue that surrounds a whole muscle is called…
epimysium
What heavier connective tissue does the epimysium blend with?
The deep fascia
What connective tissue surrounds fascicles of muscle cells?
perimysium
What connective tissue surrounds a muscle cell?
Endomysium
Are sharpey’s fibers stronger than tendon?
Yes.
Stress tears tendon before pulling tendon from muscle or bone.
What are the flat, sheet-like tendons under the palm (and scalp and foot)?
aponeuroses
Give examples of fusiform, convergent, and parallel muscles.
bicep, pecs, aaaabs (have tendinous intersections)
What’s an example of a circular muscle?
orbicularis oris
What is a fixator muscle?
Holds origin in place - such as muscle holding scapula during bicep flexion
What neurons activate skeletal muscles?
motor neurons
What is an afferent sensory neuron?
one that propagates signal toward the CNS and brain
What are two types of efferent motor neurons
Somatic
Autonomic
