musculo-skeletal system muscles + bones = locomotion

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Musculo-Skeletal System Muscles + Bones = Locomotion

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Page 1: Musculo-Skeletal System Muscles + Bones = Locomotion

Musculo-Skeletal System

Muscles + Bones = Locomotion

Page 2: Musculo-Skeletal System Muscles + Bones = Locomotion

Muscles

Page 3: Musculo-Skeletal System Muscles + Bones = Locomotion

• When you work out frequently, your muscles get larger. What do you think is happening at the cellular level to increase muscle size?

• Both men and women can increase muscle mass by exercise. Why are men able to increase their muscle mass more than women?

• Exercise that increases muscle mass is a safe way to increase metabolism to help control weight. Why does higher muscle mass increase metabolism?

WORK

TOGETHER

Page 4: Musculo-Skeletal System Muscles + Bones = Locomotion

Why muscles?• Muscle tissue is responsible for

movement and locomotion in animals.

• Muscles rely on contractile fibers to create motion.

• In vertebrate animals and arthropods, muscles attach to a skeletal system to produce locomotion.

Page 5: Musculo-Skeletal System Muscles + Bones = Locomotion

Locomotion• Locomotion is

the result of muscles pulling on skeletal systems, which is why we often study these systems together.

Page 6: Musculo-Skeletal System Muscles + Bones = Locomotion

Types of muscle tissue

•These three types are found in vertebrates:

•Skeletal: striated, voluntary control

•Smooth: involuntary control

•Cardiac: involuntary control

Page 7: Musculo-Skeletal System Muscles + Bones = Locomotion

Smooth muscle• Have contractile

fibers, but lack orderly striations of skeletal muscle.

• Where would you expect smooth muscle (involuntary control) to be found?

Page 8: Musculo-Skeletal System Muscles + Bones = Locomotion

Cardiac muscle• Influenced by

nerves and hormones, but has “electrical” system of its own to initiate and coordinate contractions.

• Where would you expect cardiac muscle to be found?

Page 9: Musculo-Skeletal System Muscles + Bones = Locomotion

Skeletal muscle• Orderly

striations are due to arrangement of contractile fibers.

• Produces locomotion.

• Where would you expect skeletal (voluntary control) muscle to be found?

Page 10: Musculo-Skeletal System Muscles + Bones = Locomotion

Which kind of muscle constricts veins when blood pressure drops suddenly?

1 2 3

76%

21%

2%

1. Smooth2. Skeletal3. Cardiac

Page 11: Musculo-Skeletal System Muscles + Bones = Locomotion

Which kind of muscle contracts during the knee-jerk reflex?

1 2 3

2% 2%

95%

1. Smooth2. Skeletal3. Cardiac

Page 12: Musculo-Skeletal System Muscles + Bones = Locomotion

Muscle fibers• A muscle cell is a

“fiber.”

• Fibers are multinucleated and contain myoglobin. (Similar to hemoglobin – what is its function?)

• Myofibrils contain the contractile fibers.

Page 13: Musculo-Skeletal System Muscles + Bones = Locomotion

Myofibril• The myofibril is

composed of “thick” and “thin” filaments.

• Each of these filaments is made up of strands of protein.

• How might this arrangement of proteins create motion?

Page 14: Musculo-Skeletal System Muscles + Bones = Locomotion

Thick and thin filaments• The thick

filaments, made mostly of myosin, have small “heads” that move.

• The thin filaments have points to which the myosin heads temporarily attach.

Page 15: Musculo-Skeletal System Muscles + Bones = Locomotion

Muscle fiber action

Page 16: Musculo-Skeletal System Muscles + Bones = Locomotion

All or nothing

• Fibers are either “on” (contracted) or “off” (relaxed).

• When lifting light weights, only a few fibers may be “on.” For heavy weights, many more may be “on,” and may take turns to prevent fatigue.

Page 17: Musculo-Skeletal System Muscles + Bones = Locomotion
Page 18: Musculo-Skeletal System Muscles + Bones = Locomotion

Skeletal muscles contract when ___ “walk” along the ___.

1 2 3 4

24%

0%7%

69%1. Actin heads; myosin fibers

2. Myosin heads, actin fibers

3. Sarcomeres, microtubules

4. Microtubles, sarcomeres

Page 19: Musculo-Skeletal System Muscles + Bones = Locomotion

What could happen if a person has a severe calcium

deficiency?

1 2 3 4

16%

5%

16%

63%1. Cross bridges would

not release from actin.

2. Muscles would not contract as strongly as they should.

3. Motor neurons would not function properly.

4. ATP would be depleted.

Page 20: Musculo-Skeletal System Muscles + Bones = Locomotion

Slow Twitch, Fast Twitch• Slow-twitch fibers: lots of myoglobin

and mitochondria. What activities would use these fibers?.

• Fast-twitch: less myoglobin, but more able to use glycolysis to quickly produce ATP. What activities would use these fibers?

• Different people have different ratios of these two fibers.

Page 21: Musculo-Skeletal System Muscles + Bones = Locomotion

Fast-twitch fibers

• Fast-twitch fibers are for bursts of strength and speed.

• The tradeoff: Fast-twitch fibers fatigue sooner.

Page 22: Musculo-Skeletal System Muscles + Bones = Locomotion

Slow-twitch fibers

• Slow-twitch fibers are for endurance.

• Trade-off: Slow-twitch fibers cannot supply a lot of power at once.

Page 23: Musculo-Skeletal System Muscles + Bones = Locomotion

A person born with lots of slow-twitch muscle fibers would be

great at:

1 2 3 4

5%0%2%

93%

1. High jump2. Cross-country

skiing3. Power lifting4. Gymnastics

Page 24: Musculo-Skeletal System Muscles + Bones = Locomotion

Working out

• Exercise can build muscle mass. However, because muscle fibers (cells) are large, they rarely divide.

• If muscle cells rarely divide, how do muscles get bigger from exercise?

Page 25: Musculo-Skeletal System Muscles + Bones = Locomotion

Stretching• Stretching exercises

add strength and flexibility by increasing muscle length.

• Again, if muscle cells do not divide, how does a cell get longer from stretching?

• Caution: stretching tendons can weaken joints.

Page 26: Musculo-Skeletal System Muscles + Bones = Locomotion

Try this:• Hold your pen or pencil so that it

casts a shadow on your paper. Line up the tip of the shadow with a point on your paper.

• How still can you hold your hand? Does the point of the shadow move? Muscles generally contract by continuous “twitching” of muscle fibers. This makes it hard to hold your hand completely steady.

Page 27: Musculo-Skeletal System Muscles + Bones = Locomotion

Review these questions:• When you work out frequently, your

muscles get larger. What do you think is happening at the cellular level to increase muscle size?

• Both men and women can increase muscle mass by exercise. Why are men able to increase their muscle mass more than women?

• Exercise that increases muscle mass is a safe way to increase metabolism to help control weight. Why does higher muscle mass increase metabolism?

Page 28: Musculo-Skeletal System Muscles + Bones = Locomotion

Skeletal Systems

Page 29: Musculo-Skeletal System Muscles + Bones = Locomotion

• Is bone living tissue? Why or why not?

• Why do broken bones take so much longer to heal than cuts in the skin?

WORK

TOGETHER

Page 30: Musculo-Skeletal System Muscles + Bones = Locomotion

Types of systems

• Three basic types of skeletal systems in the animal kingdom:

• Hydrostatic

• Exoskeleton

• Endoskeleton

Page 31: Musculo-Skeletal System Muscles + Bones = Locomotion

Hydrostatic skeleton

• Earthworms and sea anemones have a hydrostatic skeleton.

• Circular muscles squeeze the body. Longitudinal muscles shorten the body. How do these actions produce motion in the earthworm?

Page 32: Musculo-Skeletal System Muscles + Bones = Locomotion

Exoskeleton• Arthropods (insects,

spiders, etc) have an external skeleton made of chitin (a carbohydrate).

• Muscles attach to the exoskeleton, which is flexible at the joints.

• What are some advantages and disadvantages of an exoskeleton?

Page 33: Musculo-Skeletal System Muscles + Bones = Locomotion

Endoskeleton• Vertebrates have

an endoskeleton made of cartilage or bone.

• Bone and cartilage are living tissue (connective tissue).

• What are some advantages and disadvantages of an endoskeleton?

Page 34: Musculo-Skeletal System Muscles + Bones = Locomotion

What is an advantage of an exoskeleton over an

endoskeleton?

1 2 3 4

25% 25%25%25%1. Protection for

internal organs.2. Must be shed for

growth.3. Becomes heavy if

it is too large.4. Storage of

minerals.

Page 35: Musculo-Skeletal System Muscles + Bones = Locomotion

What is an advantage of an endoskeleton over an

exoskeleton?

1 2 3 4

25% 25%25%25%1. Provides external

protection.2. Grows as the

organism grows.3. Provides a point

of attachment for muscles.

4. Made of protein.

Page 36: Musculo-Skeletal System Muscles + Bones = Locomotion

Functions of the endoskeleton

• Support and protection for the body.

• Locomotion (in concert with muscles).

• Produce blood cells in bone marrow.

• Store calcium and phosphorous.

• Store energy in yellow marrow.

Page 37: Musculo-Skeletal System Muscles + Bones = Locomotion

Cartilage

• Cartilage tissue consists of chondrocytes (cartilage cells) in a matrix of collagen protein.

• Cartilage is tough, flexible material that pads joints and is found in the nose and ears.

Page 38: Musculo-Skeletal System Muscles + Bones = Locomotion

Bone tissue• Bone is made up of

bone cells in a matrix of collagen and minerals.

• Three types of bone cells: osteocytes, osteoblasts, and osteoclasts.

• Looking at this arrangement, can you see why bone and cartilage take a long time to heal?

Page 39: Musculo-Skeletal System Muscles + Bones = Locomotion

• Bones may made up of:

• Compact bone tissue.

• Spongy bone (location of red marrow)

• Marrow cavity (location of yellow marrow)

Bones

Page 40: Musculo-Skeletal System Muscles + Bones = Locomotion

Healing fractures

Page 41: Musculo-Skeletal System Muscles + Bones = Locomotion

Osteoporosis• Osteoporosis is loss

of bone mass, leading to brittle bones.

• Age, lack of calcium and Vitamin D, sedentary lifestyle, multiple pregnancies, menopause, alcohol, and smoking contribute to osteoporosis.

Page 42: Musculo-Skeletal System Muscles + Bones = Locomotion

Review these questions:

• Is bone living tissue? Why or why not?

• Why do broken bones take so much longer to heal than cuts in the skin?

Page 43: Musculo-Skeletal System Muscles + Bones = Locomotion

Locomotion

Page 44: Musculo-Skeletal System Muscles + Bones = Locomotion

Motion in Vertebrates

• Motion and locomotion are produced by muscles pulling on bones.

• Joints in the skeleton allow for parts of the body to flex and extend, allowing for motion. Ligaments attach bones to bones at the joints.

• Muscles attach to bones by tendons. Origin is on a bone that remains stationary. Insertion is on a bone that moves.

Page 45: Musculo-Skeletal System Muscles + Bones = Locomotion

Hinge joint

• A hinge joint allows flexing and extending along one plane.

• Pairs of muscles work opposite one another to create motion.

Page 46: Musculo-Skeletal System Muscles + Bones = Locomotion

Ball and socket joint

• A ball and socket arrangement allows rotational movement.

• Multiple pairs of muscles allow movement in a range of directions.

Page 47: Musculo-Skeletal System Muscles + Bones = Locomotion

Gliding joints

• In gliding joints, bones slide past one another.

• Gliding joints allow twisting motion.

Page 48: Musculo-Skeletal System Muscles + Bones = Locomotion

Movement• Flexion: decreases angle of a joint.

• Extension: increases angle of a joint.

• Abduction: movement away from midline.

• Adduction: movement toward midline.

• Rotation: turning around an axis.

Page 49: Musculo-Skeletal System Muscles + Bones = Locomotion

• The knee is a hinge joint. Find another hinge joint in the body. What muscles move it?

• The hip is a ball and socket joint. Find another ball and socket joint in the body. What muscles move it?

• The wrist is a gliding joint. Find another gliding joint in the body. What muscles move it?

WORK

TOGETHER

Page 50: Musculo-Skeletal System Muscles + Bones = Locomotion

• Give examples of joints and movements that demonstrate:

• Flexion

• Extension

• Abduction

• Adduction

• Rotation

WORK

TOGETHER

Page 51: Musculo-Skeletal System Muscles + Bones = Locomotion

Name that muscle!• For each of the following slides:

• Name the muscle or muscle group, if you can.

• State what kind of movement it produces.

• Locate the bone (or bones) that it moves.

• Which muscles produce the opposite movement?

Page 52: Musculo-Skeletal System Muscles + Bones = Locomotion

WORK

TOGETHER

Page 53: Musculo-Skeletal System Muscles + Bones = Locomotion

WORK

TOGETHER

Page 54: Musculo-Skeletal System Muscles + Bones = Locomotion

One last question:

• In what ways do muscles and the skeletal system help maintain homeostasis? Discuss and list as many ways as you can think of.