Lecture 2: Skeletal System & Joints

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Questions and Answers

What type of ossification occurs to form bones that provide urgent support or protection?

Endochondral ossification

Membranous ossification (correct)

Cartilagenous ossification

Intramembranous ossification

Which of the following is NOT a type of bone shape according to the classifications mentioned?

Dendritic bones (correct)

Short bones

Long bones

Flat bones

Which of the following statements accurately describes cartilage?

It is harder and more rigid than bone.

It is the only type of tissue in the skeletal system.

It forms the temporary skeleton of developing fetuses. (correct)

It is not present in adult humans.

Which type of bone is characterized by its spongy appearance and is found at the ends of long bones?

Cancellous bone Signup and view all the answers

What identifies a pneumatic bone?

Contains air spaces or sinuses Signup and view all the answers

What joint classification allows movement in two axes?

Biaxial synovial joint Signup and view all the answers

Which characteristic is NOT associated with synovial joints?

Infusion of synovial fluid into the bloodstream Signup and view all the answers

What type of joint is found at the base of the thumb?

Saddle joint Signup and view all the answers

Which factor does NOT contribute to the stability of a joint?

Environment temperature Signup and view all the answers

What type of synovial joint allows for simple sliding movements?

Plane synovial joint Signup and view all the answers

How many total bones are there in the axial skeleton?

80 Signup and view all the answers

Which type of joint allows for the most movement?

Synovial joint Signup and view all the answers

What is the primary function of the skeleton in relation to body movement?

Allowing movement Signup and view all the answers

What type of joint is defined by its limited mobility and includes structures like sutures?

Fibrous joint Signup and view all the answers

Which part of the skeleton houses the majority of the bones associated with the upper limb?

Appendicular skeleton Signup and view all the answers

Which of the following is included in the components of cartilaginous joints?

Hyaline cartilage Signup and view all the answers

What bones are primarily involved in the pelvic girdle?

Two hip bones Signup and view all the answers

Which bone marking is specifically associated with the ends of long bones?

Condyles Signup and view all the answers

Study Notes

Lecture 2: Skeletal System & Joints

The skeletal system is composed of cartilage and bones.
Cartilage is softer and less rigid than bone, forming a temporary skeleton in the developing fetus.
Cartilage is retained in certain areas throughout life, including the external ear, costal cartilage, air passages, and articular surfaces of most bones.
Bone is a hard, living tissue made of osteocytes, fibers, and matrix, with calcification of the extracellular matrix.
Bone tissue has different cell types: osteocytes (maintain bone tissue), osteoblasts (form bone matrix), osteogenic cells (stem cells), and osteoclasts (resorbs bone).

Types of Bone

Bones can be categorized by their shape, development, form, and location in the body.
Compact (ivory) bone forms the outer layer of all bones and the shafts of long bones. It's dense and hard.
Spongy (cancellous) bone is found inside the hard bone and the ends of long bones. It's porous and less dense.

Development of Bones

Membranous ossification: This process occurs in bones that need support or protection for vital organs like the skull.
Cartilaginous ossification: A model of the future bone is first formed in cartilage, then ossifies into bone in two steps.

Shapes of Bones

Long bones: Found in limbs (e.g., femur, tibia, humerus, radius). They have a shaft and two expanded ends.
Short bones: Subjected to pressure (e.g., carpal and tarsal bones).
Flat bones: (e.g., skull, ribs, sternum, scapula).
Irregular bones: Not easily grouped by shape (e.g., vertebrae).
Pneumatic bones: Contain air spaces called sinuses (e.g., frontal and maxillary bones).
Sesamoid bones: Small bones embedded in tendons (e.g., patella).

Parts of the Skeleton

Axial skeleton: Forms the central axis of the body (80 bones), includes skull, hyoid, vertebrae, sternum, and ribs.
Appendicular skeleton: (126 bones) includes upper and lower limbs.

Function of the Skeleton

Supports the body
Gives shape to the body
Allows for movement
Forms blood cells in bone marrow
Stores calcium and phosphorus
Protects vital organs (e.g., cranium for brain, vertebral column for spinal cord)

Bone Markings

Bone markings include elevations (e.g., linear, rounded, pointed), depressions, elongated/rounded/on edge structures, perforations (e.g., foramen, meatus, canal), heads, and condyles/trochlea.

Joints

A joint is where two or more bones are articulated.
Fibrous joints: Bones are joined by fibrous tissue. Movement is limited or absent.
- Sutures in the skull
- Syndesmosis (e.g., tibiofibular joint)
- Gomphoses (e.g., teeth in sockets)
Cartilaginous joints: Bones are connected by cartilage. Movement is limited.
- Primary cartilaginous joints (hyaline cartilage, temporary)
- Secondary cartilaginous joints (fibrocartilage, permanent)
Synovial joints: Bones are separated by a fluid-filled cavity. Movement is freely mobile. Different types of synovial joints exist (planar, hinge, pivot, condyloid, ellipsoid, saddle, ball and socket) allowing for different degrees of movement and action.

Stability of the Joint

Depends on the shape and size of articulating surfaces, ligaments, and surrounding muscles.

Summary

Differences between cartilage and bone
Classification of bones by form, development, and shape
Parts and functions of the skeleton
Types of joints
Characteristics and classification of synovial joints
Stability of joints

Questions

What type of joint is at the base of the thumb? Saddle joint
Which of the following is retained cartilage throughout life? Costal cartilage
All are examples of long bones EXCEPT: b. Scapula

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Description

This quiz covers the composition and functions of the skeletal system, including the roles of cartilage and bone. It also examines the types of bone tissue, their characteristics, and their development. Test your knowledge on the anatomy and physiology of the human skeletal framework.