Skeletal and Muscular Skeletal and Muscular SystemsSystems

Mr. Fox’s 7Mr. Fox’s 7thth Grade Science Grade Science Class.Class.

The Skeletal SystemThe Skeletal System

• A human adult has 206 bones. A human adult has 206 bones. When you are born, you have When you are born, you have between 275 and 305 bones in between 275 and 305 bones in your body. your body.

• Each bone shares the function of Each bone shares the function of the system. the system.

FunctionsFunctions

• 1. provide shape and support1. provide shape and support• 2. enables you to move2. enables you to move• 3. protection of internal organs3. protection of internal organs• 4. produce blood cells4. produce blood cells• 5. stores materials for body 5. stores materials for body

functionsfunctions

Remember!!Remember!!

• Bone is living Bone is living materialmaterial

• It contains blood It contains blood vessels and vessels and nerves, just like nerves, just like other parts of other parts of your body. your body.

Parts of the boneParts of the bone

• Bone Marrow – soft tissue in the Bone Marrow – soft tissue in the center cavity of the skeletal system.center cavity of the skeletal system.

• Cartilage – flexible, elastic, Cartilage – flexible, elastic, connective tissue found in the jointsconnective tissue found in the joints• Cushions the joints, and keeps bones Cushions the joints, and keeps bones

from rubbing together. from rubbing together.

Developing BoneDeveloping Bone

• Ossification – the process of Ossification – the process of forming bones.forming bones.• Osteoblasts form the bonesOsteoblasts form the bones• Osteocystes maintain the cellular Osteocystes maintain the cellular

activity of the bone. activity of the bone. • Osteoclasts break down bones. Osteoclasts break down bones.

Types of JointsTypes of Joints

• 1. Immovable Joint (Fixed Joint) – 1. Immovable Joint (Fixed Joint) – allow little if any movement. Joints allow little if any movement. Joints in your skull, ribs. in your skull, ribs.

Types of JointsTypes of Joints

• Ball and Socket - allows the Ball and Socket - allows the greatest range of motion. Nearly greatest range of motion. Nearly 360 degrees. 360 degrees.

• Shoulder and Hip Joints. Shoulder and Hip Joints.

Types of JointsTypes of Joints

• Hinge Joint – Like a door hinge, Hinge Joint – Like a door hinge, forward and backward movement.forward and backward movement.• Knee and ElbowKnee and Elbow

Types of JointsTypes of Joints

• Pivot (radial) Joint – allows one Pivot (radial) Joint – allows one bone to rotate around the other. bone to rotate around the other. • Lower arm, Lower legLower arm, Lower leg

Types of JointsTypes of Joints

• Sliding Joint – allows one or more Sliding Joint – allows one or more bones to slide over another.bones to slide over another.• Wrist, Ankle Wrist, Ankle

Bone ProblemsBone Problems

• Dislocation – when a bone moves Dislocation – when a bone moves out of place. Usually very painful, out of place. Usually very painful, but easily fixed. but easily fixed.

Bone ProblemsBone Problems

• Break/Fracture – when bones break Break/Fracture – when bones break in places they shouldn’t. in places they shouldn’t. • Always heal back larger so they are Always heal back larger so they are

stronger. stronger.

Bone ProblemsBone Problems

• Osteoporosis – When bones start Osteoporosis – When bones start losing their density, from a lack of losing their density, from a lack of calcium. calcium. • Happens more in womanHappens more in woman

• Arthritis – A generic term describing Arthritis – A generic term describing the inflammation of the joints. Pain, the inflammation of the joints. Pain, stiffness, swelling of the joints.stiffness, swelling of the joints.

MusclesMuscles

• It takes 42 muscles to frown, only It takes 42 muscles to frown, only 16 to smile. Smile more and save 16 to smile. Smile more and save energy. energy.

• Your body has over 600 muscles, Your body has over 600 muscles, nearly 3 times as many as its nearly 3 times as many as its bones. bones.

Muscle ActionMuscle Action

• Two types of muscle action:Two types of muscle action:• Involuntary – muscles you cannot Involuntary – muscles you cannot

control, heartbeat, breathing, control, heartbeat, breathing, digestiondigestion

• Voluntary - muscles you control, Voluntary - muscles you control, smiling movingsmiling moving

Types of MusclesTypes of Muscles

• Skeletal Muscles - muscles that Skeletal Muscles - muscles that are attached to your bones, are attached to your bones, provide the force needed to move. provide the force needed to move. • Striated fibers that tire quickly.Striated fibers that tire quickly.• Work in pairs to move bones, can only Work in pairs to move bones, can only

pull or contract. pull or contract.

Skeletal MuscleSkeletal Muscle

Types of Skeletal Types of Skeletal MuscleMuscle

• Ligament – skeletal muscles that Ligament – skeletal muscles that hold bones together at joints.hold bones together at joints.

• Tendons – skeletal muscles that Tendons – skeletal muscles that connect muscle to bone.connect muscle to bone.

• Regular Muscle – Muscles that do Regular Muscle – Muscles that do most of the work in moving the most of the work in moving the bones. bones.

Types of MuscleTypes of Muscle

• Smooth Muscle – often line the Smooth Muscle – often line the interior of body organs, stomach, interior of body organs, stomach, intestines, not striated, are intestines, not striated, are involuntary, do not tire easily.involuntary, do not tire easily.

Types of MuscleTypes of Muscle

• Cardiac Muscle – Heart muscle, Cardiac Muscle – Heart muscle, striated but involuntary, does not striated but involuntary, does not tire! tire!

Muscle at workMuscle at work

• Muscles can only contract, not Muscles can only contract, not extend. extend.

• Must work in pairs.Must work in pairs.• One muscle contracts the other One muscle contracts the other

muscle in the pair returns to its muscle in the pair returns to its original state.original state.

How on the muscle How on the muscle levellevel

• A muscle contracts when ATP A muscle contracts when ATP causes thin filaments (actin) in causes thin filaments (actin) in muscles fibers to slide over thick muscles fibers to slide over thick filaments (myosin). filaments (myosin).

myosin

actin

myosin actin

Skin!!! Skin!!!

The SkinThe Skin

• Everyone… your epidermis is Everyone… your epidermis is showing! showing!

• The skin is the largest organ in the The skin is the largest organ in the body! And the most visible.body! And the most visible.

Functions of the skinFunctions of the skin

• Major functions of the skin: Major functions of the skin: • Reduces water lossReduces water loss• Protection from injury and infectionProtection from injury and infection• Regulates body temp. Regulates body temp. • Eliminates wasteEliminates waste• Sense the environmentSense the environment• Produces vitamin D from sunlightProduces vitamin D from sunlight

Structure of the SkinStructure of the Skin

• EpidermisEpidermis – top layers of skin, no – top layers of skin, no blood vessels or nerves, surface cells blood vessels or nerves, surface cells are dead, skin pigment (melanin) is are dead, skin pigment (melanin) is found in the lower epidermisfound in the lower epidermis

• DermisDermis – lower layers of skin, – lower layers of skin, contains blood vessels, nerves, contains blood vessels, nerves, sweat glands, hair follicles, oil sweat glands, hair follicles, oil glands, and hair.glands, and hair.

Skin DiseasesSkin Diseases

• Eczema – a disease of reoccurring Eczema – a disease of reoccurring skin rashes and dryness. (very skin rashes and dryness. (very common not deadly) common not deadly)

• Acne – (PIMPLES!!!!!) More or less Acne – (PIMPLES!!!!!) More or less the changed of the hair follicles the changed of the hair follicles and sebaceous glands cause it. and sebaceous glands cause it.

• Tinea pedis – Athlete’s Foot. Is Tinea pedis – Athlete’s Foot. Is typically caused by mold! Up to typically caused by mold! Up to 15% of the U.S. population may 15% of the U.S. population may have tinea pedis.have tinea pedis.

CancerCancer

• Skin cancer – one of the many Skin cancer – one of the many forms of cancer, this one caused forms of cancer, this one caused from over exposure to UV light, from over exposure to UV light, and many other things. and many other things.

HomeworkHomework

• Finish the chapter one review. Get Finish the chapter one review. Get ready for a bone and muscle test ready for a bone and muscle test next week. next week.

• Laury is awesomeLaury is awesome