Skeletal and Muscular Systems Mr. Fox’s 7 th Grade Science Class.

The Skeletal System A human adult has 206 bones. When you are born, you have between 275 and 305 bones in your body.A human adult has 206 bones. When you are born, you have between 275 and 305 bones in your body. Each bone shares the function of the system.Each bone shares the function of the system.

Functions 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 functions5. stores materials for body functions

Remember!! Bone is living materialBone is living material It contains blood vessels and nerves, just like other parts of your body.It contains blood vessels and nerves, just like other parts of your body.

Parts of the bone Bone Marrow – soft tissue in the center cavity of the skeletal system.Bone Marrow – soft tissue in the center cavity of the skeletal system. Cartilage – flexible, elastic, connective tissue found in the jointsCartilage – flexible, elastic, connective tissue found in the joints Cushions the joints, and keeps bones from rubbing together.Cushions the joints, and keeps bones from rubbing together.

Developing Bone Ossification – the process of forming bones.Ossification – the process of forming bones. Osteoblasts form the bonesOsteoblasts form the bones Osteocystes maintain the cellular activity of the bone.Osteocystes maintain the cellular activity of the bone. Osteoclasts break down bones.Osteoclasts break down bones.

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

Types of Joints Ball and Socket - allows the greatest range of motion. Nearly 360 degrees.Ball and Socket - allows the greatest range of motion. Nearly 360 degrees. Shoulder and Hip Joints.Shoulder and Hip Joints.

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

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

Types of Joints Sliding Joint – allows one or more bones to slide over another.Sliding Joint – allows one or more bones to slide over another. Wrist, AnkleWrist, Ankle

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

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

Bone Problems Osteoporosis – When bones start losing their density, from a lack of calcium.Osteoporosis – When bones start losing their density, from a lack of calcium. Happens more in womanHappens more in woman Arthritis – A generic term describing the inflammation of the joints. Pain, stiffness, swelling of the joints.Arthritis – A generic term describing the inflammation of the joints. Pain, stiffness, swelling of the joints.

Muscles It takes 42 muscles to frown, only 16 to smile. Smile more and save energy.It takes 42 muscles to frown, only 16 to smile. Smile more and save energy. Your body has over 600 muscles, nearly 3 times as many as its bones.Your body has over 600 muscles, nearly 3 times as many as its bones.

Muscle Action Two types of muscle action:Two types of muscle action: Involuntary – muscles you cannot control, heartbeat, breathing, digestionInvoluntary – muscles you cannot control, heartbeat, breathing, digestion Voluntary - muscles you control, smiling movingVoluntary - muscles you control, smiling moving

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

Skeletal Muscle

Types of Skeletal Muscle Ligament – skeletal muscles that hold bones together at joints.Ligament – skeletal muscles that hold bones together at joints. Tendons – skeletal muscles that connect muscle to bone.Tendons – skeletal muscles that connect muscle to bone. Regular Muscle – Muscles that do most of the work in moving the bones.Regular Muscle – Muscles that do most of the work in moving the bones.

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

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

Muscle at work Muscles can only contract, not extend.Muscles can only contract, not extend. Must work in pairs.Must work in pairs. One muscle contracts the other muscle in the pair returns to its original state.One muscle contracts the other muscle in the pair returns to its original state.

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

myosin actin myosinactin

Skin!!!

The Skin Everyone… your epidermis is showing!Everyone… your epidermis is showing! The skin is the largest organ in the body! And the most visible.The skin is the largest organ in the body! And the most visible.

Functions 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 Skin Epidermis – top layers of skin, no blood vessels or nerves, surface cells are dead, skin pigment (melanin) is found in the lower epidermis Epidermis – top layers of skin, no blood vessels or nerves, surface cells are dead, skin pigment (melanin) is found in the lower epidermis Dermis – lower layers of skin, contains blood vessels, nerves, sweat glands, hair follicles, oil glands, and hair. Dermis – lower layers of skin, contains blood vessels, nerves, sweat glands, hair follicles, oil glands, and hair.

Skin Diseases Eczema – a disease of reoccurring skin rashes and dryness. (very common not deadly) Eczema – a disease of reoccurring skin rashes and dryness. (very common not deadly) Acne – (PIMPLES!!!!!) More or less the changed of the hair follicles and sebaceous glands cause it. Acne – (PIMPLES!!!!!) More or less the changed of the hair follicles and sebaceous glands cause it.

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

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

Homework Finish the chapter one review. Get ready for a bone and muscle test next week.Finish the chapter one review. Get ready for a bone and muscle test next week. Laury is awesomeLaury is awesome