skeletal ststem

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Questions and Answers

What function does the bone matrix serve?

Produces blood cells

Protects internal organs

Stores and releases hormones

Stores and releases minerals (correct)

What type of tissue fills the interior of most bones?

Bone marrow (correct)

Connective tissue

Muscle tissue

Adipose tissue

What is the purpose of red marrow?

To produce blood cells (correct)

To regulate body temperature

To provide structural support

To store fat

What is the function of sesamoid bones?

To protect tendons from compressive forces Signup and view all the answers

What is the main function of the skeletal system?

To provide structural support and protection Signup and view all the answers

What is the shape of a short bone?

Cube-like Signup and view all the answers

What type of bone is the femur?

Long bone Signup and view all the answers

What is a characteristic of flat bones?

They are typically thin and curved Signup and view all the answers

What is the function of yellow marrow?

To store fat for energy Signup and view all the answers

What is the term for the production of blood cells?

Hematopoiesis Signup and view all the answers

What is the primary function of the skeletal system?

To support the body Signup and view all the answers

What is the significance of bones in the skeletal system?

They are dynamic and complex organs Signup and view all the answers

How do bones facilitate movement?

By serving as points of attachment for muscles Signup and view all the answers

What is the role of the vertebral column in the skeletal system?

To protect the spinal cord Signup and view all the answers

What is the function of the bones in the cranium?

To protect the brain Signup and view all the answers

What is the role of bones in storing and releasing minerals and fat?

They store and release minerals and fat Signup and view all the answers

What is the significance of the skeletal system in maintaining homeostasis?

It plays a critical role in maintaining homeostasis Signup and view all the answers

What is the result of not having a skeletal system?

You would be a limp mass of organs, muscle, and skin Signup and view all the answers

What do bones serve as in the skeletal system?

Points of attachment for muscles Signup and view all the answers

What is the relationship between muscles and bones in the skeletal system?

Muscles and bones work together to facilitate movement Signup and view all the answers

What type of bone is the patella?

Sesamoid bone Signup and view all the answers

What is the main function of vertebrae?

To provide support for the weight of the head, neck, and trunk Signup and view all the answers

How many bones are found in the vertebral column?

24 bones Signup and view all the answers

What is a characteristic of cartilage?

It is rich in proteoglycan and elastin fibers Signup and view all the answers

What is the function of lubricin in cartilage?

To play a major role in bio-lubrication and wear protection Signup and view all the answers

What is a joint?

A place where adjacent bones or bone and cartilage come together Signup and view all the answers

What is the function of tendons and ligaments?

To support muscles and joints Signup and view all the answers

What is the axial skeleton?

The part of the skeleton that forms the vertical, central axis of the body Signup and view all the answers

How many bones are found in the axial skeleton of an adult?

80 bones Signup and view all the answers

What is the original number of vertebrae in the vertebral column?

33 vertebrae Signup and view all the answers

What is the primary function of the vertebral column?

To provide support for the weight of the head, neck, and trunk Signup and view all the answers

How many bones are in the vertebral column?

26 bones Signup and view all the answers

What is the name of the curved vertebrae located at the bottom of the spine?

Sacrum Signup and view all the answers

What is the result of the fusion of four small coccygeal vertebrae?

Coccyx Signup and view all the answers

What is the name of the skeleton that includes all bones of the upper and lower limbs?

Appendicular skeleton Signup and view all the answers

How many bones are in the appendicular skeleton of an adult?

126 bones Signup and view all the answers

What is necessary for calcium absorption from the small intestine?

Vitamin D Signup and view all the answers

What is the role of parathyroid hormone (PTH) in bone health?

To stimulate osteoclasts Signup and view all the answers

What is the result of lack of mechanical stress on bones?

Loss of mineral salts and collagen fibers Signup and view all the answers

What is the estimated rate of bone mass loss per month in astronauts during long space missions?

1% to 2% per month Signup and view all the answers

Study Notes

Functions of the Skeletal System

Supports the body
Facilitates movement
Protects internal organs
Stores and releases minerals and fat
Produces blood cells

Supporting the Body

Bones and cartilage compose the scaffold that supports the rest of the body
Without the skeletal system, the body would be a limp mass of organs, muscle, and skin

Facilitating Movement

Bones facilitate movement by serving as points of attachment for muscles
Bones act as levers and joints serve as fulcrums
Unless a muscle spans a joint and contracts, a bone is not going to move

Protecting Internal Organs

Bones protect internal organs from injury by covering or surrounding them
Examples include the ribs protecting the lungs and heart, and the bones of the vertebral column protecting the spinal cord

Storing and Releasing Minerals and Fat

Bone tissue performs several critical functions on a metabolic level
Bone matrix acts as a reservoir for several minerals essential to the body, especially calcium and phosphorus
These minerals can be released back into the bloodstream to maintain levels needed to support physiological processes
Calcium ions are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses
Bone also serves as a site for fat storage

Producing Blood Cells

Bone is also the site for blood cell production
The softer connective tissue that fills the interior of most bones is referred to as bone marrow
There are two types of bone marrow: yellow marrow and red marrow
Red marrow is where hematopoiesis—the production of blood cells—takes place
Red blood cells, white blood cells, and platelets are all produced in the red marrow

Organs of the Skeletal System

Bones
Cartilage
Joints
Ligaments and tendons

Bones

Bone, or osseous tissue, is a hard, dense connective tissue that forms most of the adult skeleton
The skeletal system is the body system composed of bones and cartilage and performs several critical functions for the human body

Types of Bones

Long bones
Short bones
Flat bones
Irregular bones
Sesamoid bones

Long Bones

A long bone is one that is cylindrical in shape, being longer than it is wide
Long bones function as levers; they move when muscles contract

Short Bones

A short bone is one that is cube-like in shape, being approximately equal in length, width, and thickness
Short bones provide stability and support as well as some limited motion

Flat Bones

The term “flat bone” is somewhat of a misnomer because, although a flat bone is typically thin, it is also often curved
Examples include the cranial bones, the scapulae, the sternum, and the ribs
Flat bones serve as points of attachment for muscles and often protect internal organs

Irregular Bones

An irregular bone is one that does not have any easily characterized shape and therefore does not fit any other classification
Examples include the vertebrae that support the spinal cord and protect it from compressive forces
Many facial bones, particularly the ones containing sinuses, are classified as irregular bones

Sesamoid Bones

A sesamoid bone is a small, round bone that, as the name suggests, is shaped like a sesame seed
These bones form in tendons where a great deal of pressure is generated in a joint
Sesamoid bones protect tendons by helping them overcome compressive forces
Sesamoid bones are typically found in tendons associated with the feet, hands, and knees

The Vertebrae

Provides support for the weight of the head, neck, and the trunk
Protects the spinal cord
Maintains an upright body position
Consists of 26 bones

Cartilage

Cartilage is composed of specialized cells called chondrocytes that produce a large amount of collagenous extracellular matrix, abundant ground substance that is rich in proteoglycan and elastin fibers
Cartilage does not contain blood vessels or nerves

Joints

A joint, also called an articulation, is any place where adjacent bones or bone and cartilage come together to form a connection
Joints are classified both structurally and functionally

Ligaments and Tendons

A ligament is the fibrous connective tissue that connects bones to other bones
A tendon connects muscle to bone
They are all made of connective tissue
Tendons and ligaments function is to support muscles and joints

The Axial Skeleton

The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back
It serves to protect the brain, spinal cord, heart, and lungs
It also serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip joints to move their corresponding limbs

The Appendicular Skeleton

The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones that attach each limb to the axial skeleton
There are 126 bones in the appendicular skeleton of an adult

Factors Affecting Bone Growth and Maintenance

Heredity
Nutrition
Hormones
Exercise or stress

Heredity

Genetic factors play a significant role in determining bone mass

Nutrition and Bone Tissue

Calcium is a critical component of bone, especially in the form of calcium phosphate and calcium carbonate
Vitamin D is essential for calcium absorption

Hormones

The skeletal system is no exception, as multiple hormones modulate and support bone health
Two hormones that affect the osteoclasts are parathyroid hormone (PTH) and calcitonin

Exercise and Bone Tissue

Lack of mechanical stress causes bones to lose mineral salts and collagen fibers, and thus strength
Mechanical stress stimulates the deposition of mineral salts and collagen fibers
Resistance training is especially important to slow down the eventual bone loss due to aging and for preventing osteoporosis

Disorders of the Skeletal System

Arthritis
Bursitis
Gout
Osteomyelitis
Osteoporosis
Rickets
Tumors
Scurvy
Fractures

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