Overview of the Skeletal System

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of marrow is responsible for producing blood cells?

Red marrow (correct)

Yellow marrow

Bone marrow

White marrow

Which cells function in the absorption and clear away of bone matrix?

Chondrocytes

Osteocytes

Osteoclasts (correct)

Osteoblasts

What is the primary inorganic component that gives bone its hardness?

Collagen

Calcium carbonate

Sodium chloride

Hydroxyapatite (correct)

Which type of bone is characterized by a dense structure and provides strength?

Compact bone Signup and view all the answers

Which hormone, released by the kidneys, stimulates the formation of red blood cells?

Erythropoietin Signup and view all the answers

What is a closed (simple) fracture?

A break in the bone that does not penetrate the skin Signup and view all the answers

Which type of fracture is often due to excessive twisting of the bone?

Spiral fracture Signup and view all the answers

What is the first step in the repair of a bone fracture?

A hematoma is formed Signup and view all the answers

What characterizes a comminuted fracture?

The bone is splintered into multiple pieces Signup and view all the answers

Which type of fracture is commonly found in children and is characterized as incomplete?

Greenstick fracture Signup and view all the answers

What is the purpose of reduction in fracture treatment?

Realignment of the fractured bone Signup and view all the answers

What occurs after a fibrocartilage callus is formed in fracture repair?

A bony callus is formed Signup and view all the answers

What is an open (compound) fracture?

A break that penetrates through the skin Signup and view all the answers

What type of bone is mainly homogeneous and found in long bones?

Compact bone Signup and view all the answers

Which component is found in an osteon of compact bone?

Osteocytes Signup and view all the answers

What differentiates spongy bone from compact bone?

Spongy bone contains small needle-like pieces of bone. Signup and view all the answers

What is the primary role of osteoblasts in bone histology?

To form bone matrix by secreting collagen. Signup and view all the answers

Which canals connect blood vessels and nerves between adjacent central canals in compact bone?

Volkman canals Signup and view all the answers

What type of bone formation site is typical in adults?

Spongy bone Signup and view all the answers

What is the main characteristic of trabecular bone?

It is poorly organized and consists of needle-like pieces. Signup and view all the answers

What is the embryonic tissue from which osteoprogenitor cells are derived?

Mesenchyme Signup and view all the answers

What remains cartilaginous until secondary ossification occurs?

Epiphyses Signup and view all the answers

What role do osteoblasts play in bone growth?

They lay down matrix of compact bone. Signup and view all the answers

Which hormones are involved in regulating bone growth?

hGH and sex hormones Signup and view all the answers

How does appositional growth increase the diameter of bones?

By adding new bone on the outer surface. Signup and view all the answers

What happens to cartilage cells during longitudinal bone growth?

They are produced and destroyed. Signup and view all the answers

What type of fracture is characterized by an incomplete fracture of the bone, commonly found in youth?

Greenstick fracture Signup and view all the answers

What is the primary function of osteoclasts?

To reabsorb bone matrix. Signup and view all the answers

Which phase of bone repair involves fibroblasts producing fibrocartilage to fill the gap between broken bone ends?

Fibrocartilage callus formation Signup and view all the answers

At what age is the ossification of most bones typically completed?

By age 25 Signup and view all the answers

What term describes the process of fixing a simple fracture without surgery?

Closed reduction Signup and view all the answers

What process involves the continuous remodeling of bone throughout life?

Bone remodeling and repair Signup and view all the answers

What type of fracture involves bone breaking into multiple pieces?

Comminuted fracture Signup and view all the answers

What is the inorganic component of bone that provides strength and rigidity?

Hydroxyapatite Signup and view all the answers

How long does it typically take for a fracture to heal in adults, excluding long bones or the elderly?

6-8 weeks Signup and view all the answers

Which type of ossification involves the formation of flat bones between layers of connective tissue?

Intramembranous ossification Signup and view all the answers

Which cells are responsible for breaking down bone tissue?

Osteoclasts Signup and view all the answers

What role does parathyroid hormone (PTH) play when blood calcium levels are low?

Stimulates osteoclast activity Signup and view all the answers

Which vitamin is primarily responsible for increasing intestinal absorption of dietary calcium?

Vitamin D Signup and view all the answers

How does calcitonin function in the body when blood calcium levels are high?

Inhibits osteoclast activity Signup and view all the answers

What is the primary effect of human growth hormone (hGH) on bone tissue?

Stimulates cartilage cell reproduction Signup and view all the answers

What contributes to the mineral composition required for bone remodeling?

Calcium and Magnesium Signup and view all the answers

What is the effect of estrogen on bone growth compared to androgens?

Greater effect than androgens Signup and view all the answers

How does exercise influence bone growth?

Thickens bones due to stress Signup and view all the answers

Which mineral is needed for osteoblast activity?

Magnesium Signup and view all the answers

What is the primary function of calcitonin in calcium homeostasis?

Inhibit bone reabsorption Signup and view all the answers

What is a common consequence of Vitamin D deficiency?

Rickets in children Signup and view all the answers

Study Notes

Skeletal System Overview

The skeletal system is a complex structure, composed of bones, cartilage, and ligaments.
It provides support, protection, movement, and mineral storage.

Functions of Bone Tissue

Support: Legs and pelvis support body weight; the atlas (first cervical vertebra) supports the skull.
Protection: The skull protects the brain, eyes, and ears; the rib cage and shoulder girdle protect the heart and lungs; the pelvic girdle protects lower abdominal organs and reproductive organs.
Movement: Skeletal muscles attach to bones via tendons, enabling movement. Muscles use bones to work in opposition to cause movement.

Mineral Homeostasis

Bones store minerals, including calcium phosphate, magnesium, sodium, potassium, and carbonate ions.
Bones also store potentially harmful minerals like lead, radium, and strontium.
Yellow bone marrow in long bone shafts serves as an energy storage site (fat). This yellow marrow can revert back to red marrow if blood cells are needed.

Hematopoiesis

Blood cell formation occurs within the red marrow of certain bones.
In children, red marrow is primarily in the medullary cavities of long bones.
In adults, red marrow is primarily in spongy bone of the skull, ribs, sternum, clavicles, vertebrae, and hip bones.

Bone Classification by Shape

Long Bones: Typically longer than wide, with a shaft and heads at both ends. Examples: femur, humerus, and all limb bones (except wrist and ankle).
Short Bones: Generally cube-shaped. Examples: carpals (wrist) and tarsals (ankle).
Flat Bones: Thin layers of compact bone around a layer of spongy bone; usually curved. Examples: skull, ribs, sternum, and scapula.
Irregular Bones: Irregular shape that does not fit into other classifications. Examples: vertebrae, hip bones, and auditory ossicles.
Sesamoid Bones: Round bones embedded within tendons adjacent to joints. Example: patella.

Bone Structure - Gross Anatomy

Diaphysis: The shaft of a long bone, consisting of a medullary cavity filled with marrow and surrounded by a thick collar of compact bone.
Epiphyses: The expanded ends of a long bone, primarily spongy bone, and surrounded by a thin layer of compact bone.
Epiphyseal Plate: An area of hyaline cartilage at the junction of the epiphyses and diaphysis, allowing for lengthwise growth in long bones.
Epiphyseal Line: The remnant of the epiphyseal plate in mature bones.
Periosteum: Tough, dense fibrous connective tissue that covers the outer surfaces of bones, containing osteogenic cells (allowing for osteoblast formation and bone repair). It's supplied with blood vessels and nerves, and serves as an insertion point for tendons and ligaments.
Endosteum: Thin, inner lining of the medullary cavity, containing osteoblasts and osteoclasts for bone growth and repair.
Articular Cartilage: Hyaline cartilage covering the external surfaces of the epiphyses; reducing friction at joint surfaces.
Sharpey's Fibers: Fibers that secure the periosteum to the underlying bone.
Medullary Cavity: The hollow central region of the diaphysis that holds marrow.
Nutrient Arteries: Blood vessels that supply bone cells with nutrients and enter the bone tissue through the nutrient foramen in compact bone.

Bone Fractures and Repair

Fracture: A break in a bone.
Types: Simple/closed (does not break skin), Compound/open (penetrates the skin) and other fractures based on shape.
Treatment: Reduction (realignement) and immobilization (e.g., closed reduction - bones to normal position, open reduction - surgery); treatment time varies depending on the type of fracture (6-8 weeks).
Major Steps of Repair: Hematoma formation, Fibrocartilage callus formation, Bony callus formation and remodelling.

Bone Development and Growth

Embryonic Skeleton: Initially composed of hyaline cartilage.
Ossification (beginning during gestation): Intramembranous (flat bones between connective tissue sheets) and endochondral (bone starts as hyaline cartilage) processes.
Longitudinal Growth: Lengthening at epiphyseal plates due to cartilage growth and replacement by bone.
Appositional Growth: Thickening of bones via activity of periosteal osteoblasts laying down matrix of compact bone (outer surface) and osteoclasts destroying bone matrix on the endosteal surface.

Bone Remodeling and Repair

Bone remodeling occurs throughout life, involving continuous actions of osteoblasts and osteoclasts.
Hormonal regulation (calcitonin, parathyroid hormone) is crucial for maintaining bone calcium homeostasis.
Necessary minerals and vitamins (Vitamin D, Magnesium, Calcium and Vitamins B12, A and C) also promote bone remodeling and repair.
Exercise also contributes towards increasing bone growth.

Bone Growth Control

Bone growth is controlled by hormones, like human growth hormone (hGH) and sex hormones (estrogen and testosterone).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the complex structure of the skeletal system, including its functions and components. Learn about the critical roles of bones in support, protection, and movement, as well as their importance in mineral homeostasis. This quiz will enhance your understanding of how the skeletal system contributes to overall health.