Human Skeleton Anatomy

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Questions and Answers

Which type of bone is characterized by a honeycomb structure and is less dense than cortical bone?

Irregular bone

Trabecular bone (correct)

Flat bone

Cortical bone

What is the primary mineral found in bone that contributes to its rigidity?

Hydroxyapatite (correct)

Calcium carbonate

Bone mineral protein

Collagen

How is the adult human skeleton divided by shape?

Flat, cortical, and trabecular bones

Compact, spongy, and irregular bones

Cortical, irregular, and flat bones

Long, flat, and irregular bones (correct)

Why does archaeological bone tend to be brittle after death?

Loss of collagen fibers Signup and view all the answers

What type of bone tissue forms the outer layer of bones and is the thickest in the shafts of long bones?

Cortical bone Signup and view all the answers

What is one of the primary roles of the skeletal system?

Providing a framework to support the body Signup and view all the answers

What characteristic of long bones maximizes strength while minimizing weight?

Tubular form Signup and view all the answers

Which component of bone acts as a reservoir for fat storage?

Medullary cavity Signup and view all the answers

Why are trabecular bones found in the epiphyses?

To withstand and dissipate mechanical forces Signup and view all the answers

What does Wolff's Law state about bone adaptation?

Bone adapts to the strains placed upon it. Signup and view all the answers

What is the main difference between woven bone and lamellar bone?

Woven bone has a more porous structure. Signup and view all the answers

What type of bone primarily comprises the walls of the diaphysis?

Cortical bone Signup and view all the answers

How does bone formation begin?

As woven or primary bone that is later replaced Signup and view all the answers

What is the primary role of osteoblasts in the context of cartilage transformation into bone?

They serve as a framework for bone matrix deposition. Signup and view all the answers

What is formed first during the ossification process?

A thin sleeve of bone around the cartilage model. Signup and view all the answers

During longitudinal growth, what happens to the growth plates of juvenile bones?

They ossify and fuse with the shaft. Signup and view all the answers

How does the process of bone growth in width differ from its longitudinal growth?

Bone is deposited beneath the periosteum and resorbed from the endosteum. Signup and view all the answers

What is the term for the initial center of bone formation?

Primary ossification center. Signup and view all the answers

What is left behind as chondrocytes grow, enlarge, and die?

Spaces in the cartilage. Signup and view all the answers

What happens to the interior of the shaft as the bone grows?

It is hollowed out to form the medullary cavity. Signup and view all the answers

During growth, how is the width of the metaphysis managed?

Bone is deposited on the internal surface of the cortex. Signup and view all the answers

What is the primary role of osteoblasts in bone tissue?

Formation of new bone Signup and view all the answers

Which of the following structures interconnects Haversian channels in the bone?

Volkmann's canals Signup and view all the answers

Which type of ossification primarily forms the clavicle?

Intramembranous ossification Signup and view all the answers

Where are osteocytes located within the bone tissue?

In lacunae Signup and view all the answers

What are interstitial lamellae?

Lamellae found between osteons Signup and view all the answers

Which cell type is primarily responsible for the resorption of bone tissue?

Osteoclasts Signup and view all the answers

The Haversian system consists of interconnected channels primarily oriented in which direction?

Parallel to the long axis of the bone Signup and view all the answers

Which structure provides blood supply to trabecular bone?

Blood vessels within its honeycomb structure Signup and view all the answers

What is the primary function of osteoblasts in intramembranous ossification?

To secrete osteoid Signup and view all the answers

At what stage of prenatal life does ossification of the bony skeleton begin?

Sixth week Signup and view all the answers

Which type of human teeth are primarily designed for crushing and grinding food?

Premolars and molars Signup and view all the answers

What connects a tooth to its surrounding alveolar bone?

Periodontal ligament Signup and view all the answers

How many total teeth are present in adult dentition?

32 Signup and view all the answers

What is the role of osteocytes in bone tissue?

To maintain bone tissue Signup and view all the answers

Which layer of a tooth is the hardest substance in the human body?

Enamel Signup and view all the answers

What is the purpose of the apical foramen in a tooth?

To allow nerves and blood vessels to enter the pulp chamber Signup and view all the answers

Study Notes

Human Skeleton

The adult human skeleton consists of 206 bones, including small bones known as sesamoid bones in the tendons of the hands and feet.
Bones are classified by their shape: long bones found in limbs, flat bones, and irregular bones like vertebrae
Bones are made of: 64% mineral, 26% organic material, 10% water
Organic material is primarily collagen fibres.
Mineral portion of bone is calcium phosphate, which gives bone rigidity
Two different types of bone tissue: cortical bone and trabecular bone
- Cortical bone is solid and dense
- Trabecular bone is less dense with a honeycomb structure
The outer surface of bone is coated with a membrane called the periosteum.
The inner cavity of long bones where marrow is located is lined with a membrane called the endosteum.
Functions of bones:
- Provide a framework to support the body
- Bear ridges for the attachment of muscles and tendons
- Form surfaces for joints
- Protect vital organs.
- Store fats
- Provide blood-forming marrow
- Act as a bank of mineral salts.

Bone Structure

Long bone morphology maximizes strength and minimizes weight.
The medullary cavity within the shaft provides space for bone marrow and fat storage.
The metaphyses (neck portion) support the epiphyses (rounded tips of long bones).
Epiphyses are mostly made of trabecular bone, which withstands mechanical forces on joints.
Epiphyses are sites of red blood cell production in juveniles.
The large surface area of the epiphyses facilitates mineral exchange.
Diaphysis (bone shaft) walls are composed of cortical bone for strength and rigidity.
Bone is a living tissue that adapts to strain through Wolff's Law.
Woven bone is a temporary, coarser, more porous bone tissue that is later replaced by lamellar bone (more compact type).
Lamellar bone is composed of layered lamellae, arranged in concentric layers around Haversian channels.
Haversian canals run parallel to the long bone axis and are connected by Volkmann's canals.
Interstitial lamellae are found between osteons, and circumferential lamellae surround the bone's outer and inner surfaces.
Trabecular bone lacks Haversian systems and receives blood supply through a network of vessels.

Bone Cells

Three main types of bone cells:
- Osteoblasts: form new bone
- Osteocytes: maintain bone tissue
- Osteoclasts: resorb bone tissue

Bone Formation

Osteoblasts produce an organic matrix (osteoid) which is then mineralized.
Osteocytes are located within the bone tissue and maintain bone tissue.
Osteoclasts resorb bone tissue through acidic dissolution and enzymatic degradation.
Bone develops from an embryonic tissue called mesenchyme.
Two main types of ossification:
- Endochondral ossification: bone develops from a cartilage model, most bones formed this way.
- Intramembranous ossification: bone forms directly from mesenchyme, found in clavicle, mandible, and skull bones.

Endochondral Ossification

Mesenchymal cells differentiate into chondrocytes, which form cartilage.
Cartilage cells grow, enlarge, and die, leaving spaces.
Blood vessels invade the area, bringing osteoblasts and osteoclasts.
Osteoblasts use the cartilage framework to lay down bone matrix.
A sleeve of bone forms around the center of the cartilage model and calcifies.
This process continues as the bone grows in length and width.
The initial center of bone formation is the primary ossification center.
Secondary ossification centers (epiphyses) appear at long-bone ends, connected to the shaft by growth plates.
Growth plates ossify, uniting the epiphysis with the shaft.
Long bone growth in width is achieved by bone deposition on the outer surface and resorption on the inner surface.

Intramembranous Ossification

Mesenchymal cells differentiate into osteoblasts within a fibrous membrane.
Osteoblasts secrete osteoid, which then mineralizes.
Osteoblasts become trapped and differentiate into osteocytes.
Bone expands outward as more osteoblasts form, creating a trabecular network, which later becomes compact bone.
Ossification of the bony skeleton begins in the sixth week of prenatal life.
Skeletal growth is complete by about 25 years of age.

Human Teeth

Teeth are classified into four types:
- Incisors: for cutting
- Canines: for puncturing and tearing
- Premolars: for crushing and grinding
- Molars: for crushing and grinding
Humans develop two sets of teeth: deciduous (milk) teeth, and permanent (adult) teeth.
Deciduous dentition: 20 teeth total
Adult dentition: 32 teeth total
Each tooth consists of a crown (above gum), root(s) in the jaw, and a neck where the crown and root meet.
Teeth are attached to the jaw by the periodontal ligament, containing connective tissue fibres, blood vessels, and nerves.
The apical foramen is an opening at the root tip for nerves, blood vessels, and other tissues.

Tooth Structure

Teeth consist of:
- Enamel: outermost layer
- Cementum: layer covering the root
- Dentine: the bulk of the tooth, surrounding the pulp cavity and root canal.
Dental pulp: soft tissue within the tooth, contains nerves and blood vessels.

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Description

Test your knowledge about the human skeleton! This quiz covers the structure, types, and functions of bones, providing important insights into their anatomy and biology. Discover details about bone composition and classification as well.