1. Animal Systems
Muscle System

2. Muscular System
Function-- to move the animal about, to provide movement for the proper functioning of the organs.
Meat production -- muscles are processed into meat; % of the animal’s body is muscle.

4. Three types of muscle

5. Skeletal Muscle
Movement -- movement for the bones of the skeleton and other voluntary movement; composed of long, striated bundles that contract and relax
Tendons -- connect muscles to bones
Red Muscle -- contain many mitochondria; lots of blood; contract for long periods of time

7. Skeletal Muscle
White Muscle -- Fewer mitochondria; contract faster; fatigue faster.

9. Smooth Muscle
Movement -- Controls movements of the internal organs; involuntary; non-striated sheets.
Examples-- Digestive tract, urinary tract

11. Cardiac Muscle
Movement -- muscles that control the heart; striated and arranged in bands; involuntary; amazing
Stamina -- # of times a heart beats in a lifetime?

15. D. List the Three Types of Muscles
Skeletal Muscles
Attached to bones
Voluntary
Striated
The skeleton and the skeletal muscles function together allowing an animal to move.

16. Skeletal Muscle

17. D. List the Three Types of Muscles
In addition to skeletal muscles, other types of muscles include:
Smooth muscles
Found in blood vessels, digestive tracts, and reproductive tracts
Involuntary, Not striated
Cardiac muscles
Are found in the heart.
Involuntary, Striated

18. Smooth Muscle

19. Cardiac Muscle

20. E. Point out how Muscles aid in Movement
Vertebrates move by the actions of muscles on bones.
Muscles generally work in pairs to produce movement:
when one muscle flexes (or contracts) the other relaxes, a process known as antagonism.

21. E. Point out how Muscles aid in Movement
The striations with in the muscle cell are thread-like structures called myofibrils.
Within each myofibril there are dense lines called Z lines.
A sarcomere (or muscle functional unit) extends from Z line to Z line.

23. E. Point out how Muscles aid in Movement
Each sarcomere has thick and thin filaments.
The thick filaments are made of myosin and occupy the center of each sarcomere.
Thin filaments are made of actins and anchor to the Z line.

24. Sarcomere

25. E. Point out how Muscles aid in Movement
Muscles contract by shortening each sarcomere.
The sliding filament model of muscle contraction has thin filaments on each side of the sarcomere sliding past each other until they meet in the middle.
Myosin filaments have club-shaped heads that project toward the actin filaments.

26. Contraction of a Sarcomere

27. E. Point out how Muscles aid in Movement
Myosin heads attach to binding sites on the actin filaments.
The myosin heads swivel toward the center of the sarcomere, detach and then reattach to the nearest active site of the actin filament.
Each cycle of attachment, swiveling, and detachment shortens the sarcomere 1%. Hundreds of such cycles occur each second during muscle contraction.