Q2-Masticatory Dynamics Flashcards
Carnivores have; teeth with (high/low) cusps TMJ restricted \_\_\_\_\_\_\_ TMJ at level of \_\_\_\_\_ \_\_\_\_ emphasis of \_\_\_\_\_\_ muscle zygomatic arch is (narrow/wide)
high mobility tooth row (generates force) temporalis narrow
Carnivores have a primarily (vertical/horizontal) TMJ movement
vertical (generates a lot of force)
Herbivores have; teeth with (low/high) cusps TMJ \_\_\_\_\_ mobile TMJ \_\_\_\_ \_\_\_\_ tooth row emphasis on \_\_\_\_\_\_\_/\_\_\_\_ \_\_\_\_ muscles zygomatic arch (narrow/wide)
low/flat highly elevated above masseter/medial pterygoid wide
The load of the TMJ will be generally (higher/lower) when the resultant is more distant from the bite point
higher
True or False
The human TMJ is loaded during chewing
False; a recent paper suggests that human TMJs are not loaded during chewing
The importance of human TMJ loading is that the minimization of TMJ loading is believed to reduce the likelihood of ____ _____ ____
degenerative joint diseases
This style of teeth involves the last upper premolar and first lower molar specially adapted for tearing flesh
carnassial teeth
The force generated by a muscle (is/is not) directly proportional to the cross-sectional area of all its fibers
IS (i.e. large muscles generate more force and power)
Individual muscle fibers are capable of shortening to ___-___ their length
one-half (therefore longer muscles can produce a large range of movement)
Muscles that have fibers running the entire length of the muscle belly are referred to as _____ muscles
strap
Muscles that have many fibers that do not extend to the entire length of the muscle belly and are located within tendons planes are referred to as ______ muscles
pennate
These muscles work to close the jaw (3)
masseter (both heads)
temporalis
medial pterygoid
These muscles work to open the jaw (2)
lateral pterygoid (both heads) digastrics (both bellies)
The main difference between jaw openers and jaw closers is…..
jaw openers are strap muscles and jaw closers are pennate muscles
The fulcrum of the jaw muscle-joint lever system is the…..
axis of cervical spine
The jaw muscle-joint lever system is a ____ class lever
first
The ____ class lever is the most efficent
first
Lever efficiency depends of ____ and ______
d1 and d2
D1 is the distance between the fulcrum and (weight/power) and D2 is the distance between the fulcrum and (weight/power)
D1 = weight D2 = power
A (lower/higher) D1/D2 ratio is more efficient
lower
Mastication is a ____ class lever system
second
The weight of a second class lever system is between the _______ and ____ ____
fulcrum and applied force
The fulcrum in the second class lever system is the ______ _____
opposing TMJ
Biting is a _____ class lever system
third
The fulcrum of a third class lever system is the ____; and force is applies between the ____ and ______
TMJ
fulcrum and weight
Third class lever produces (rapid/slow), (high/low) force jaw movements
rapid
low
The mechanical advantage along the mandible _______ with the distance from the TMJ
increases; that is the MA is lower close to the joint
Jaw-closing muscles express multiple types of myosin when impart differences in _________ velocity and _____ generation
shortening
power
Fibers with (high/low) speed and power are (more/less) economical
high
less
Muscle fibers that express (fast/slow) types of myosin are found (close/further) from the joint
fast
close