Introduction to the Skeletal System

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Questions and Answers

What defines long bones from other types of bones?

They have a complex shape that protects internal organs.

They have a shaft that contains the medullary cavity. (correct)

They are generally cube-shaped and have equal length and width.

They consist of spongy bone located between two layers of compact bone.

Which of the following examples represents a short bone?

Cranium of the skull

Carpus of the hand (correct)

Humerus

Tibia

What type of bone is primarily responsible for protecting internal organs due to its complex shape?

Short bones

Flat bones

Irregular bones (correct)

Long bones

What occurs during endochondral ossification?

Cartilage is replaced by bone. Signup and view all the answers

Which of the following bones is classified as a flat bone?

Sternum Signup and view all the answers

Which of the following bones is not included among the bones of the lower limb?

Radius Signup and view all the answers

Which bone is classified as a long bone?

Radius Signup and view all the answers

Which of the following bones is classified as an irregular bone?

Hip Signup and view all the answers

What is the number of thoracic vertebrae?

12 Signup and view all the answers

What are the ribs from 1-7 called, which are attached to the sternum?

True ribs Signup and view all the answers

How many cervical vertebrae are present in the human body?

7 Signup and view all the answers

What type of bone are the vertebrae of the vertebral column classified as?

Irregular Signup and view all the answers

Which of the following bones belongs to the upper limb?

Ulna Signup and view all the answers

What is the primary function of ligaments in the skeletal system?

To connect two bones together Signup and view all the answers

Which type of bone structure provides the hard external layer of bones?

Compact bone Signup and view all the answers

What material primarily comprises the hard intercellular substance found in bone?

Collagen and calcium phosphate Signup and view all the answers

How are tendon and ligament structures different?

Tendons connect muscle to bone while ligaments connect bone to bone. Signup and view all the answers

What is the appearance of spongy bone characterized by?

A spongy appearance due to small holes Signup and view all the answers

Which type of bone develops in dense membranes?

Membranous bone Signup and view all the answers

What type of bone primarily fills the inner spaces with marrow and blood vessels?

Spongy bone Signup and view all the answers

What feature characterizes osteons in compact bone?

They enclose central canals containing blood vessels and nerve fibers. Signup and view all the answers

How many cranial bones are present in the skull?

8 Signup and view all the answers

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

33 Signup and view all the answers

Which of the following best describes the composition of the thoracic cage?

Includes thoracic vertebrae, ribs, and sternum Signup and view all the answers

Which classification correctly identifies the ribs attached to the sternum?

False ribs are 8-10 Signup and view all the answers

Which part of the sternum is located at the top?

Manubrium Signup and view all the answers

Which bones are considered part of the appendicular skeleton?

Pelvic girdle and femur Signup and view all the answers

What function does the skull serve?

Protect the brain and facilitate senses Signup and view all the answers

Which of the following statements is true regarding the lumbar vertebrae?

They are the largest vertebrae Signup and view all the answers

Study Notes

Introduction

The skeletal system is an organ system comprised of bone, cartilage, ligaments, and tendons.
This system works together with the muscular and articular system to grant movement.
Muscles provide support and produce movement.
Joints provide support and bind parts together.

Parts of the Skeletal System

Bones: Make up the skeleton.
Cartilages: Flexible connective tissue.
Ligaments: Connective tissues that attach bones together in joints.
Tendons: Fibrous connective tissues that attach muscles to bones.

The Bone

Bone is a rigid body tissue comprised of cells embedded in hard intercellular material.
The material is made of collagen and calcium phosphate.

Types of Bone

According to Structure

Compact bone (cortical bone): Forms the hard exterior layer of all bones, provides protection and strength and consists of Osteons that each enclose a central canal that holds blood vessels and nerve fibers.
Spongy bone (cancellous bone): Forms the inner layer of all bones, is porous and light and contains marrow and blood vessels.

According to Morphology (Shape)

Long bones: Consist of a proximal end, a shaft with a medullary cavity where red bone marrow and yellow bone marrow are stored, and a distal end.
Short bones: Generally cube-shaped, with equal length and width.
Irregular bones: Vary in shape and structure and often protect internal organs.
Flat bones: Composed of a layer of spongy bone between two thin layers of compact bone.

According to Development

Intramembranous Ossification: Bone develops from fibrous connective tissue membranes.
Endochondral Ossification: Bone is first developed by hyaline cartilage which gets replaced by bone.

The Skeleton

Consists of the Axial Skeleton (80 bones) and the Appendicular Skeleton (126 bones)

Axial Skeleton (80 bones)

Consists of the skull bones, vertebral column, and thoracic cage.

Skull Bones

Protect the brain, entrances to the respiratory system, digestive system, the eyes in the orbital cavity, and the middle and inner ear.
The skull contains 22 bones, 8 cranial bones (cranium) and 14 facial bones.

Cranium of the Skull

Comprised of eight bones: Frontal (2), Parietal (2), Temporal (2), occipital (1), Sphenoid (1), and Ethmoid (1).

Facial Bones

Protect and support the entrances to the digestive and respiratory tracts.
Composed of 14 bones: maxillary (2), mandible (1), nasal (2), vomer (1), inferior nasal conchae (2), zygomatic (2), lacrimal (2), palatine (2).

Vertebral Column

Also called the spine, spinal column, or backbone, composed of vertebrae
It is about 71 cm in males and 61 cm in females.
There are 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacrum (fused), and 4 coccyx (fused).

Thoracic Cage

Consists of 12 thoracic vertebrae, 12 pairs of ribs, and the sternum
Ribs and sternum form the rib cage.

Ribs

Ribs 1-7 are attached to the sternum (true ribs).
Ribs 8-10 are attached to the cartilage of the 7th rib (false ribs)
Ribs 11-12 are floating ribs.

Sternum

Has three parts: Manubrium, body, and xiphoid process.

Appendicular Skeleton (126 bones)

Consists of the upper limb, lower limb, pectoral girdle, and pelvic girdle.

Lower Limb Appendicular Skeleton

Consists of: Pelvic girdle, femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

Common Questions

Flat bones: Sternum, Cranium of the skull, Scapula
Long bones: Femur, Tibia, Radius, Ulna.
Irregular bones: Vertebrae of the vertebral column, Hip bones, Most of the skull bones.
Axial Skeleton: Sternum.
Lower Limb: Radius.
Number of Thoracic Vertebrae: 12
Hollow Spaces inside the Skull surrounding the Nasal Cavity: Paranasal Sinuses.
Number of Cervical Vertebrae: 7.
Ribs 1-7: True Ribs.
Type of Vertebrae: Irregular.
Upper Limb: Ulna.

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Description

Explore the fundamentals of the skeletal system, including its components such as bones, cartilage, ligaments, and tendons. This quiz will test your understanding of the structure and function of bone types. Perfect for students studying anatomy.