Skeletal, Muscular, and Integumentary Systems Chapter 45 Table of Contents Section 1 The Human Body...

Skeletal, Muscular, and Integumentary SystemsChapter 45

Table of Contents

Section 1 The Human Body Plan

Section 2 Skeletal System

Section 3 Muscular System

Section 4 Integumentary System

Section 1 The Human Body PlanChapter 45

Objectives

• Describe four types of tissues that make up the human body.

• Explain how tissues, organs, and organ systems are organized.

• Summarize the functions of the primary organ systems in the human body.

• Identify the five human body cavities and the organs that each contains.


Body Tissues• All tissues are a collection of

cells that have a similar structure and that work together to perform a particular function.

• Muscle Tissue

– Muscle tissue is composed of cells that can contract in a coordinated fashion.


Body Tissues, continued

• Muscle Tissue, continued

– The human body has three types of muscle tissue: skeletal, smooth, and cardiac.

• Skeletal muscle moves the bones in your trunk, limbs, and face.

• Smooth muscle handles body functions that you cannot control consciously.

• Cardiac muscle, found in your heart, pumps blood through your body.



• Nervous Tissue

– Nervous tissue contains cells, or neurons, that receive andtransmit messages in the form of electrical impulses.

– Neurons are nerve cells that are specialized to receive and send electrical impulses.



• Nervous Tissue, continued

– Nervous tissue can be found throughout the human body and has various functions.

• For example, nervous tissue can be found in the brain and sensory organs and is used to interpret sensory information.



• Epithelial Tissue

– Epithelial tissue is tissue that is composed of a sheet of cells and that covers a body surface or lines a body cavity.

– Epithelial tissue is found in various thicknesses and arrangements, depending on where it is located.



• Epithelial Tissue, continued

– Each epithelial layer

is formed from cells

that are tightly bound

together, often

providing a protective

barrier for these

surfaces.



• Connective Tissue

– Connective tissue is a tissue that has a lot of intracellular substance and that connects and supports other tissues.



• Connective Tissue, continued

– Connective tissues are the most abundant and diverse of the four types of tissue and contain a substance called matrix.

– Matrix is an intracellular substance that gives connective tissue its strength and flexibility and can be solid, semisolid, or liquid.

Chapter 45

Human Body Tissues


Chapter 45

Click below to watch the Visual Concept.

Visual Concept

Body Tissues



Organs and Organ Systems

• An organ consists of various tissues that work together to carry out a specific function.

• Groups of organs interact in an organ system.

• Organ systems work together to function in an efficient, integrated manner.

Chapter 45

Major Organ Systems of the Human Body



Organs and Organ Systems, continued

• Integration of Organ Systems

– An even higher level of organization is the integration of organ systems.

– The integration of organ systems can be described as each organ system having organs associated with it according to that organ’s primary function. This is so the organ system can work more efficiently.

Chapter 45


Visual Concept

Overview of Organ Systems



Body Cavities

• Many organs and organ systems in the human body are housed in compartments called body cavities.

• These cavities protect internal organs from injuries and permit organs to function while remaining securely supported.

• Each human cavity can contains one or more organs.


Body Cavities, continued

– The human body has five main body cavities, including the cranial cavity, the spinal cavity, the thoracic cavity, the abdominal cavity, and the pelvic cavity.

– The cranial cavity is the cavity that contains, supports, and protects the brain.

– The spinal cavity is the cavity that contains, supports, and protects the spinal cord.


Body Cavities, continued

• The thoracic cavity is the cavity that contains, supports, and protects the heart, esophagus, and the organs of the respiratory system.

• The abdominal cavity is the cavity that contains, supports, and protects the digestive system.

• The pelvic cavity is the cavity that contains, supports, and protects the organs of the reproductive and excretory systems.

Chapter 45

Cavities of the Human Body


Chapter 45


Visual Concept

Human Body Cavities


Section 2 Skeletal SystemChapter 45

Objectives

• Distinguish between the axial skeleton and the appendicular skeleton.

• Explain the function and structure of bones.

• Summarize how bones develop and elongate.

• List three types of joints and give an example of each.

• Describe a common disorder that affects the skeleton.


The Skeleton

• A skeleton is the bones of a human or animal body that form the framework of the body, support the muscles and organs, and protect the inner organs.

• The variation in size and shape among the bones that make up the skeleton reflects their different roles in the body.

Chapter 45

Human Skeleton



The Skeleton, continued

• The human skeleton is composed of two parts—the axial skeleton and the appendicular skeleton.

• The bones of the arms and legs, along with the scapula, clavicle, and pelvis, make up the appendicular skeleton.

• The bones of the skull, ribs, spine, and sternum form the axial skeleton.

Chapter 45


Visual Concept

Anatomy of a Human Skeletal System



Bone Function and Structure

• The bones that make up the skeleton function in a variety of ways, such as supporting the muscles, protecting internal organs, helping movement, and playing vital roles in important metabolic processes.

• Bones do not make up most of a body’s mass.


Bone Function and Structure, continued

• Long Bone Structure

– A long bone’s surface is covered by a tough membrane called the periosteum.

– Periosteum is a white, double layered membrane that covers the entire surface of bone except for the joint surfaces and is richly supplied with nerve fibers and blood vessels.



• Long Bone Structure, continued

– Under the periosteum is a hard material called compact bone, and this part of the bone gives all bones their strength and rigidity.

– Compact bone is composed of cylinders made of mineral crystals and protein fibers called lamellae.




– Each lamellae is made up of a narrow channel called a Haversian canal, which contains the blood vessels in compact bone.

– Surrounding each Haversian canal are protein fibers and osteocytes.

• Osteocytes are a specific type of bone cell.




– Beneath some compact bone is a network of connective tissue called spongy bone.

– Spongy bone is less dense bone tissue that has many open spaces.

Chapter 45

Structure of Bone




• Bone Marrow

– Bone marrow is a soft tissue inside some bones that can be either red or yellow.

– The type of bone marrow present determines both its composition and function.

Chapter 45


Visual Concept

Parts of a Human Bone - 1 & 2




• Injury and Repair

– Despite their strength, bones will crack or even break if they are subjected to certain situations or are overused.

– A crack or break is referred to as a fracture.

• A fracture is an injury in which the tissue of a bone is broken.


Bone Development

• During fetal development, some bones that were originally cartilage will slowly be replaced by actual bone. This process is called ossification.


Bone Development, continued

• Bone Elongation

– Bones continue to grow after a person’s birth.

– Bone elongation and growth take place near the ends of long bones in an area known as the epiphyseal plate.

• The epiphyseal plate is found at the joint ends of long bones and is composed of cartilage. This area of bone will eventually become mature bone.

Chapter 45


Visual Concept

Human Bone Growth



Joints

• The place where two bones meet is known as a joint.

• Three major kinds of joints are found in the human body—fixed, semimovable, and movable.

• Fixed Joints

– A fixed joint is a joint at which no movement occurs.


Joints, continued

• Semimovable Joints

– A semimovable joint is one that will permit limited movement.

– Cartilage can be involved to help these joints move.


Joints, continued

• Movable Joints

– A movable joint is a joint at which a wide range of motion occurs.

– There are different types of movable joints, including hinge, ball-and-socket, pivot, saddle, and gliding.

– A hinge joint allows limited movement in only one plane.


Joints, continued

• Movable Joints, continued

– A ball-and-socket joint is another type of moveable joint and allows 360 degree movement in 2 planes.

– A pivot joint allows 180 degree movement in only one plane.

– A saddle joint will allow 360 degree movement in only one plane.

– A gliding joint allows bones to slide over one another.


Joints, continued

• Joint Structure

– Joint structure helps movable joints deal with the pressure and stress of everyday life.

– Joints are covered with cartilage and secrete synovial fluid to reduce friction. Joints are also connected with ligaments to aid in joint movement.

– Even with all this protection a joint can still be injured.


Joints, continued

• Joint Structure, continued

– The term arthritis is used to describe disorders that cause painful, swollen joints.

• Rheumatoid arthritis develops when the immune system begins to attack body tissues, and joints become stiff and deformed.

• Osteoarthritis is a degenerative joint disease in which the cartilage covering the surface of bone becomes thinner and rougher.

Chapter 45

Types of Joints


Chapter 45


Visual Concept

Types of Joints


Section 3 Muscular SystemChapter 45

Objectives

• Distinguish between the three types of muscle tissues.

• Describe the structure of skeletal muscle fibers.

• Explain how skeletal muscles contract.

• Describe how muscles move bones.

• Explain the process in which a muscle becomes fatigued.


Muscle Types

• A muscle is an organ that can contract in a coordinated fashion and includes muscle tissue, blood vessels, nerves, and connective tissue.

• Their ability to contract and relax not only enables the body to move, but also provides the force that pushes substances, such as blood and food, through the body.

• The human body has three types of muscle tissues: skeletal, smooth, and cardiac.


Muscle Types, continued

• Skeletal muscles consciously control the moving parts of the body and are often referred to as voluntary muscles.

• Skeletal muscles are made up of muscle fibers.

– Muscle fibers consist of multinucleated elongated cells with light and dark stripes. These stripes are called striations.



• Muscle fibers are grouped into bundles called fascicles.

• Groups of fascicles are bound together by connective tissue to form a muscle.

• The connective tissue in skeletal muscle cells can unite to form tendons.



• Smooth muscles are spindle-shaped, have a single nucleus, and interlace to form sheets.

• Smooth muscle lacks striations, and the connective tissue that surrounds it cannot form tendons.

• Smooth muscle forms the walls of the stomach, intestines, blood vessels, and other internal organs. Because most of its movements cannot be consciously controlled, smooth muscle is referred to as involuntary muscle.



• Cardiac muscle makes up the walls of the heart.

• Cardiac muscle shares some characteristics with both skeletal muscle and smooth muscle.

– As with skeletal muscle, cardiac muscle tissue is striated; as with smooth muscle, it is involuntary and each cell has one nucleus.

Chapter 45

Three Types of Muscle Tissue


Chapter 45


Visual Concept

Anatomy of the Human Muscular System



Muscle Structure

• A skeletal muscle fiber is a single, multinucleated muscle cell.

• Although muscle fibers make up most muscle tissue, a large amount of connective tissue, blood vessels, and nerves are also present.

• Connective tissue covers and supports each muscle fiber and reinforces the muscle as a whole.


Muscle Structure, continued

• Each skeletal muscle fiber has a nerve ending that controls its activity.

• Muscles produce large amounts of metabolic waste that must be removed through veins.

• A skeletal muscle fiber contains bundles of structures called myofibrils.

– A myofibril is a threadlike structure that contains two types of protein.



• Each myofibril is made up of two types of protein filaments—thick ones and thin ones.

• The thick filaments are mostly made of the protein myosin, which is also the most abundant protein in muscle tissue.

• The thin filaments are made of the protein actin, which is the protein that functions in the contraction and relaxation of muscles.



• Since actin filaments are the main protein in contraction and relaxation, actin filaments are anchored at their endpoints and create a structure called the Z line.

• The region from one Z line to the next is called a sarcomere. This unit is the basic unit of contraction for skeletal and cardiac muscle.

Chapter 45

Skeletal Muscle



Muscular Contraction

• When a nerve impulse stimulates a muscle to contract, the myosin filaments’ heads attach to points on the actin filaments.

• The myosin heads then bend inward, pulling the actin with them.

• The myosin heads then let the actin go, bend back into their original position, attach to a new point on the actin filament, and pull again.


Muscular Contraction, continued

• The action just described shortens the sarcomere, and when all the sarcomeres of a muscle fiber are shortened, the muscle fibers (and thus the muscle) contract.

• Muscle contraction requires energy, which is supplied by ATP.

• Because myosin heads must attach and detach a number of times during a single muscle contraction, muscle cells must have a continuous supply of ATP.

Chapter 45

Contraction of a Muscle


Chapter 45


Visual Concept

Muscle Contraction



Muscular Contraction, continued

• Muscle contraction is an all-or-none response—either the fibers contract or they remain relaxed.

• The force of a muscle contraction is determined by the number of muscle fibers that are stimulated.

– As more fibers are activated, the force of the contraction increases.


Muscular Movement of Bones

• Muscles are attached to the outer membrane of bone, the periosteum, either directly or by a tough fibrous cord of connective tissue called a tendon.

• The point where the muscle attaches to the stationary bone is called the origin.

• The point where the muscle attaches to the moving bone is called the insertion.


Muscular Movement of Bones, continued

• Most skeletal muscles are arranged in opposing pairs, and muscles move bones by pulling them.

• The muscle that bends a joint is known as a flexor.

• A muscle that straightens a joint is known as an extensor.

• In order for smooth movement, one muscle in a pair must contract while the opposing muscle relaxes.

Chapter 45

Opposing Muscles in the Arm


Chapter 45


Visual Concept

Muscular Movement and Bones



Muscle Fatigue

• Muscle cells store glycogen, which provides muscles with energy.

• During prolonged and vigorous exertion and when glucose has been used up, fat molecules are utilized for energy.

• When energy availability fails to keep pace with its use, muscle fatigue sets in. Muscle fatigue is the physiological inability of a muscle to contract, and is a result of a relative depletion of ATP.


Muscle Fatigue, continued

• Oxygen Debt

– When the level of oxygen coming into the body is not enough to meet the demands of energy production, an oxygen debt is established.

• Oxygen debt is the extra amount of oxygen that must be taken in by the body to replenish the muscles’ oxygen reserves and to allow for the breakdown of lactic acid within the muscles.

Section 4 Integumentary SystemChapter 45

Objectives

• Describe the functions of the skin.

• Distinguish between the two layers that form skin.

• Identify two types of glands found in the skin, and describe their functions.

• Describe the structure of nails.

• Describe the structure of hair.


Skin

• Skin is composed of two layers the epidermis and the dermis.

• Epidermis

– The epidermis is the outer layer of skin and is composed of flattened epithelial cells.

– The cells of the epidermis are filled with a protein called keratin, which gives skin its rough, leathery texture and its waterproof quality.


Skin, continued

• Epidermis, continued

– The color of skin is mainly determined by a brown pigment called melanin, which is produced by cells in the lower layers of the epidermis.

• The amount of melanin produced in skin depends on two factors: heredity and the length of time the skin is exposed to ultraviolet radiation.


Skin, continued

• Dermis

– The dermis is the inner layer of skin and is composed of living cells and other specialized structures.

– These specialized cells help the skin protect the body as much as possible.


Skin, continued

• Glands

– The skin contains exocrine glands, which are glands that release secretions through ducts. The main exocrine glands present in the skin are sweat glands and oil glands.

– Sweat glands are distributed throughout the body and release excess water salts and urea. Sweat glands also help regulate the bodies temperature.


Skin, continued

• Glands, continued

– Oil glands are excretory glands that secret a substance called sebum. Oil glands are also called sebaceous glands.

– Sebum is an oily secretion that prevents excess water loss, softens hair and skin, and protects the body by being mildly toxic to some bacteria.

• Acne occurs when the ducts of oil glands become clogged with excessive amounts of sebum, dead cells, and bacteria.

Chapter 45

Structure of Skin


Chapter 45


Visual Concept

Parts of the Skin



Nails

• Nails help protect the fingers and toes by forming nail roots under skin folds at the base and sides of the nail.

• Nails are also made primarily of keratin and rest on a bed of tissue filled with blood vessels.

• Nails can be an indicator of some kinds of diseases due to their composition and location.

Chapter 45


Visual Concept

Cross Section of Fingernail



Hair

• Hair protects and insulates the body and is produced by hair follicles, which are clusters of cells at the base of deep dermal pits.

• Hair is composed of keratin and is kept soft by the oil glands associated with the hair follicle.

• Hair color is the result of the presence of the pigment melanin in the hair shaft.

Skeletal, Muscular, and Integumentary Systems Chapter 45 Table of Contents Section 1 The Human Body...

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