Muscular System

Functions of the Muscular System

• Move the body• Regulate materials moving

within the body– Size of blood vessels– Pyloric valve in the stomach– Pupil of the eye

• Move food through the digestive tract (smooth muscle)

MUSCLES ARE THE MAIN ORGAN OF THE MUSCULAR SYSTEM!

There are more than 600 skeletal muscles in the human body!

Voluntary Muscles

• Muscles you can control– All skeletal

muscles

Involuntary Muscles

• Muscles you do not consciously control– Smooth muscle in

digestive system– Cardiac (heart

muscle)

– Pupil of the eyes (sphincter muscle)

– Blood vessel walls Smooth muscle

Cardiac Muscle

3 TYPES OF MUSCLE TISSUEMade of 3 kinds of cells

INVOLUNTARY

VOLUNTARY

INVOLUNTARY

When skeletal muscles contract

• Muscles move by contracting. This is the only movement they can make.

• It takes two muscle groups to move a bone, one to contract and move the bone and another to contract and move the bone back to the original position

Contracted

Relaxed

When smooth muscles contract

Thought Question• What are the organs of the

muscular system?– The muscles

• What are the three types of muscle cells?– Skeletal muscle or striated muscle– Smooth muscle– Cardiac muscle

Skeletal muscle with striations – found in muscles that move bones

Smooth muscle- found in digestive tract and blood vessels

Cardiac Muscle – found in the heart

Thought Question• What are the major muscle groups of the

body?– Trapezoids– Deltoids– Pectorals– Biceps brachii– Triceps brachii– Abdominals– Latissimus dorsi– Gluteus maximus– Biceps femorus– Rectus femoris– Gastrocnemius

Thought Question

• What cell organelle corresponds most closely to the muscular system?– The mitochondrion • It burns oxygen and glucose to make

energy for the cell. Skeletal muscle cells have extra mitochondrion in them to help them burn more energy

Thought Question

• How do the muscular and skeletal systems interact to apply forces?–When a muscle contracts, it pulls on

the tendon at the end of the muscle which is attached to the bone.

– The bone is moved like a lever– The opposing muscle group must

then contract to apply the opposite force to move the bone back to the original position

Thought Question

• How can the force done by muscles be calculated?– The force applied by a muscle can

be measured using instruments• Hand grips• Weights • Spring scales

Thought Question

• How do the skeletal and muscular systems interact to transform energy both internally and externally?–Muscle cells burn glucose and oxygen to

transform chemical energy to mechanical and heat energy

–Mechanical force applied by muscles is transferred to bones as motion

– Potential (chemical) to kinetic (mechanical) to kinetic (mechanical)

A

B

C

• Which image shows a voluntary muscle?•Which images show involuntary muscles?•Which images show striated muscles?•Which type of muscles are involved in peristalsis?•Which type of muscle is associated with tendons?•Why do muscle cells have more mitochondrion than other types of cells?

• HERE’S A LITTLE SONG TO HELP YOU REMEMBER!

• http://youtu.be/vvBWnQJHGBs