Post on 28-Dec-2015
transcript
There are 3 types of muscles:
• Smooth-cover organs such as digestive system. A wavelike motion in the digestive system which allows food to move is called Peristalsis.
• Cardiac-these are found in the heart and are specialized to keep going and going…
• Skeletal-skeletal muscle fiber is a single cell that contracts in response to stimulation, then they release. They are a thin, elongated cylinder and contain myofibrils for contractions.
Skeletal Muscle, continued…
Skeletal muscle contains 2 types of protein filamentsthick ones=protein Myosin
Thin ones+ protein Actin(alternations create dark and light bands in
muscle)Part of myofibril that extends is called the
sarcomere: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__sarcomere_contraction.html
Skeletal muscle, cont.
– Each skeletal muscle connects by a nerve cell called a Motor Neuron
– At the end of each motor neuron there are tiny vesicles that store chemicals called neurotransmitters that stimulate the muscle to contract
– A muscle fiber usually has a single motor and plate that is densely branched. This allows them to connect to many muscle fibers
– Together, the motor neuron and muscle fibers it controls is called a motor unit
Motor Unit
• Esophagus - food passageway (heartburn is caused by the effects of gastric juice on the esophagus)
• Stomach - secretes gastric juices (pepsin, hydrochloric acid) which digest proteins and creates a paste of food called chyme.
• Pancreas - secretes pancreatic juice which helps digest carbs, fats, and nucleic acids and proteins.