Anatomy - Outcome 11 Flashcards
What are muscles composed of?
Each muscle is composed of several small fibers held together by a thin membrane like fascia which allows the muscles to be serparated from other structures in the area
Each muscle has an origin and an insertion…
the orgin is usually fixed, or the least movable structure
the insertion is usually attached to the more moveable structure
What percentage do muscles make up of the body’s weight?
40-50%
There are essentially 3 types of muscle tissue:
- cardiac - found in the heart
- smooth - located in the stomach, intestinal walls, blood vessels, urinary tract and ducts
- skeletal - responsible for bodily movements and breathing
Skeletal Muscle
Each skeletal muscle consists of a body and two attachments. The body contains muscular tissue. The attachments are fibrous tissue and attach the muscle at both ends to bones, ligaments, tendons, skin, or sometimes to each other
Depression definition
to lower or closer
Elevation definition
to lift or close
Lateral excursion definition
to move side to side
Mastication definition
to chew and grind
Protrusion definition
to move forward or extend
Retrusion definition
to pull backward or inwards
What is Mastication?
a series of highly coordinated functions that involve the teeth, tongue, muscles of mastication, lips, cheeks, and sailva in the preparation of food for swallowing and digestion
There are three starges of mastication:
- Cutting of food
- Crushing of food into smaller particles
- Grinding of food
When the impulse to massticate food..
When the impulse to masticate food is relayed along with the muscles of mastication, the mucle fibers shorten, pulling toward their origin and thus providing joint action. This reflex action allows the muscles of mastication to play a major role in preparing food for swalloing
The rest position
The teeth are arranged in both arches so that when the muscles of mastication bring the jaws together, the teeth meet in a function relationship known as occlusion, with the upper and lower teeth not quite in contact, but with a space of 2 to 5mm betwween the anterior teeth. This is known as the rest position
The muscles of mastication have the ability to…
Have the ability to move the lower jaw (mandible) from side to side, as well as the ability to protract or retract the mandible
The act of mastication consists of…
Placing food between the anterior teeth and closing until the teeth meet with the lower incisors to the lingual of the upper incisors. Then, with a shearing motion, a piece of food is cut free. The portion is then transfered by the tongue to the posterior teeth and is held in position by the cheeks and positerior teeth to reduce the food to “bits”. After the food has been prepared for swallowing, the tongue propels it against the posterior of the palate and into the pharynx, and down into the stomache
Masseter Muscle - Origin & Insertion
Origin: zygomatic arach (lower boder and medial side) fibers run downard and slightly backward
Insertion: angle of the mandible, lateral side
Temporal Muscle - Origin & Insertion
Origin: Temporal fossa superior to the suture joining the temporal and paretal bones
Insertion: Coronoid process of the mandible
The Medial (Internal) Pterygoid - Origin & Insertion
Origin: pterygoid plate and fossa (part of the sphenoid bone) and maxillary tuberosity
Insertion: angle of the mandible (medial side)