Unit 1: Bone Anatomy and Functions

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Questions and Answers

At what age is the anterior fontanelle usually fully ossified?

6-12 months old

2-3 months old

12-18 months old (correct)

18-24 months old

How many separate vertebrae make up the vertebral column excluding the sacrum and coccyx?

24 (correct)

What is the primary reason the skull bones do not fuse at an early stage?

To facilitate bone healing processes

To allow for moulding of the baby’s head during childbirth (correct)

To accommodate rapid brain growth

To prevent infection during childbirth

Which part of the skull is responsible for protecting the delicate structures of the inner ear?

Temporal bone Signup and view all the answers

What denotes the identification of each vertebra in terms of its region and position?

A letter for the region followed by a number Signup and view all the answers

What is one of the primary functions of bones in the human body?

Providing structural support Signup and view all the answers

Which type of bone is primarily characterized by having a diaphysis and two epiphyses?

Long bones Signup and view all the answers

What mineral is primarily stored in bones and is essential for maintaining blood calcium levels?

Calcium phosphate Signup and view all the answers

Which of the following bones is an example of a short bone?

Carpals Signup and view all the answers

What type of cells are responsible for the breakdown of bone tissue?

Osteoclasts Signup and view all the answers

Where is red bone marrow primarily located in the human body?

In the spongy bone of short and irregular bones Signup and view all the answers

What is the role of the periosteum in bone structure?

Protecting the bone and containing bone-forming cells Signup and view all the answers

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

Patella Signup and view all the answers

Which vertebrae are the smallest in the human body?

Cervical vertebrae Signup and view all the answers

What is the primary function of the intervertebral discs?

To act as shock absorbers Signup and view all the answers

How many thoracic vertebrae are there in the human body?

12 Signup and view all the answers

What are the lowest two pairs of ribs referred to as?

Floating ribs Signup and view all the answers

Which bones form the shoulder girdle?

Two clavicles and two scapulae Signup and view all the answers

What is the connective tissue that attaches ribs to the sternum called?

Cartilage Signup and view all the answers

Which vertebrae are the largest in the human body?

Lumbar vertebrae Signup and view all the answers

What forms the anterior part of the thoracic cage?

Sternum Signup and view all the answers

What is the primary component of bone that constitutes 65% of its composition?

Calcium phosphate Signup and view all the answers

Which type of bone cell is responsible for monitoring and maintaining bone tissue?

Osteocyte Signup and view all the answers

What term describes the bones forming the central bony core of the body?

Axial skeleton Signup and view all the answers

Which of the following bones is not part of the cranium?

Zygomatic bone Signup and view all the answers

Which bone is longer than the radius?

Ulna Signup and view all the answers

What is the primary function of osteoclasts in bone tissue?

Breaking down bone Signup and view all the answers

What is the correct order of the carpal bones in the proximal row from outside inwards?

Scaphoid, Lunate, Triquetrum, Pisiform Signup and view all the answers

How many bones form the skeleton of the face, excluding the frontal bone?

13 Signup and view all the answers

Which of the following correctly describes the pelvic girdle?

Formed by the hip bones, sacrum, and coccyx Signup and view all the answers

Fontanelles in the skull are areas of incomplete ossification, primarily found in which age group?

Infants Signup and view all the answers

Which types of bones are included in the appendicular skeleton?

Shoulder and pelvic girdles Signup and view all the answers

Which bone is not part of the innominate bones of the hip?

Femur Signup and view all the answers

What is a unique feature of the female pelvis compared to the male pelvis?

Rounder and roomier structure Signup and view all the answers

Which of the following statements about the phalanges is correct?

They articulate with the metacarpal bones and each other Signup and view all the answers

What joint is formed by the head of the femur and the acetabulum?

Hip joint Signup and view all the answers

How many bones make up the metacarpal region of the hand?

5 Signup and view all the answers

Study Notes

Overview of Bone

Bone is a metabolically active connective tissue providing structural support, facilitating movement, and protecting vital organs.
The adult human skeleton comprises 206 bones.
Functions of bone include:
- Providing the body framework
- Attachment for muscles and tendons
- Enabling movement through joints
- Protecting cranial, thoracic, and pelvic organs
- Haemopoiesis: blood cell production in red bone marrow
- Mineral storage, especially calcium phosphate for blood calcium maintenance

Types of Bones

Bones are classified into five categories:
- Long Bones: Longer than wide; examples include femur, tibia, and fibula.
- Short Bones: Cube-like; e.g., carpals in the wrist.
- Irregular Bones: Various shapes; e.g., vertebrae and some skull bones.
- Flat Bones: Thin and flat; e.g., sternum, ribs, most skull bones.
- Sesamoid Bones: Embedded in tendons; e.g., patella (kneecap).

Bone Structure

Long Bones:
- Composed of a diaphysis (shaft) and two epiphyses (ends).
- Diaphysis mainly contains compact bone and a central medullary canal with yellow bone marrow.
- Epiphyses covered with compact bone, containing spongy bone inside.
- Separated by epiphyseal cartilages that ossify after growth.
- Surrounded by periosteum, with outer fibrous and inner osteogenic layers.
Short, Irregular, Flat, and Sesamoid Bones:
- Thin outer compact bone with an inner layer of spongy bone containing red marrow.
- Enclosed by periosteum, except cranial bone interiors covered by dura mater.

Composition of Bone

Made of 65% inorganic material (calcium salts, primarily calcium phosphate) providing hardness.
Remaining 35% is organic material (osteoid, mainly collagen) contributing strength and flexibility.
Cellular component of bone is less than 2% of total mass.

Bone Cells

Osteoblasts: Bone-forming cells that deposit inorganic salts and osteoid.
Osteocytes: Mature bone cells maintaining bone tissue.
Osteoclasts: Bone-resorbing cells breaking down bone and releasing calcium and phosphate.

Classification Based on Location

Bones divided into two groups:
- Axial Skeleton: Skull, vertebral column, ribs, sternum.
- Appendicular Skeleton: Shoulder and pelvic girdles, limb bones.

Axial Skeleton

Skull: Composed of cranium and facial bones.
- Cranium protects the brain, consists of flat and irregular bones.
- Important bones include frontal, parietal (2), temporal (2), occipital, sphenoid, and ethmoid bones.
- Facial skeleton consists of 13 bones, including zygomatic, maxilla, nasal, and mandible.
Vertebral Column: Comprises 26 bones, including cervical (7), thoracic (12), lumbar (5), sacrum, and coccyx.
- Functions to protect spinal cord, provide movement, and support the trunk.
Thoracic Cage: Made of the sternum, 12 pairs of ribs, and thoracic vertebrae.
- Ribs articulate with the vertebrae posteriorly, and true ribs connect directly to the sternum.

Appendicular Skeleton

Shoulder Girdle: Includes 2 clavicles and 2 scapulae, providing body connectivity.
Upper Limb:
- Humerus (upper arm), ulna and radius (forearm), carpal bones (wrist), metacarpal bones (hand), and phalanges (finger bones).
Pelvic Girdle: Basin-shaped structure formed by hip bones, sacrum, and coccyx.
- Hip bones are formed by ilium, ischium, and pubis.
- Differences in male and female pelvises accommodate childbirth.
Lower Limb:
- Includes femur (thigh), tibia (medial lower leg), fibula (lateral lower leg), and patella (knee cap).
- The femur is the longest and heaviest bone, transmitting body weight to the foot.

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Description

Explore the essential roles of bone as a living connective tissue. This quiz covers the structure of the human skeleton, its 206 bones, and key functions such as support, movement, and protection of vital organs. Test your understanding of how bones connect with muscles and joints for body movement.