Joints-difinition

Definition, Classification and Importance of Joints

by

Joints – Definition and Classification

One of the crucial attributes that distinguish living organisms from non-living is the capability to locomote and move.

  • This feature is vital for survival as living organisms are required to adjust to their environment and accommodate their biological requirements such as food, self-preservation, and mating.
  • Most living organisms have their special systems for mobility and movement.
  • These might consist of basic structures such as cilia, and flagella, or a lot more intricate structures like wings or feet.
  • The significant key elements that assist in locomotion are bones and muscles.
  • In humans and other vertebrates, the bones form a framework called the skeletal system that provides structure and shape.
  • Additionally, these bones allow motion through different kinds of joints.
Table of Contents Hide
Joints

A joint, likewise referred to as an articulation or articular surface, is a connection that is present between bones in the skeletal system. Joints provide the means for movement. The type and characteristics of a joint determine its degree and type of movement. Joints can be categorized based upon structure and function.

Babies start with about 270 bones. Some of these bones fuse together during growth. Adults have about 206 bones. So, the estimated number of joints in the body is between 250 and 350.

The inclusion of sesamoids

Sesamoids are bones embedded in tendons, but not connected to other bones. The patella (kneecap) is the largest sesamoid. These bones differ in number from person to person.

Classification of Joints

The body has 3 primary kinds of joints. They’re categorized by the movement they enable:

Classification-of-Joits

Synarthroses (immovable)

These are fixed or fibrous joints. They’re specified as two or more bones in close contact that have no motion. The bones of the skull are an example.

Types of Fibrous Joints

There are three kinds of fibrous joints:

  • (1)Sutures are immovable joints that link bones of the skull. These joints have actually serrated edges that lock together with fibers of connective tissue.
  • (2) The fibrous expressions between the teeth and the mandible or maxilla are called gomphoses and are also immovable.
  • (3) A syndesmosis is a joint in which a ligament connects two bones, permitting a little motion (amphiarthroses). The distal joint in between the tibia and fibula is an example of a syndesmosis.
Amphiarthroses (slightly movable)

Also called cartilaginous joints, these joints are defined as two or more bones held so securely together that just restricted movement can occur. The vertebrae of the spine are good examples.

Types of Cartilaginous Joints

There are two types of cartilaginous joints:

  • (1) A synchondrosis is an immovable cartilaginous joint. One example is the joint between the first pair of ribs and the sternum.
  • (2) A symphysis includes a compressible fibrocartilaginous pad that connects two bones. This type of joint allows for some motion. The hip bones, linked by the pubic symphysis, and the vertebrae, connected by intervertebral discs, are examples of symphyses.
Diarthroses (freely movable)

Likewise known as synovial joints, these joints have synovial fluid enabling all parts of the joint to efficiently move against each other. These are the most common joints in the human body. Examples include joints like the knee and shoulder.

Types of Synovial Joints

There are six kinds of synovial joints:

(1) Gliding joints move against each other on a single plane. Significant gliding joints include the intervertebral joints and the bones of the wrists and ankles.

(2) Hinge joints move on simply one axis. These joints enable flexion and extension. Significant hinge joints consist of the elbow and finger joints.

(3) A pivot joint provides rotation. At the top of the spine, the atlas and axis form a pivot joint that enables rotation of the head.

(4) A condyloid joint enables circular movement, flexion, and extension. The wrist joint between the radius and the carpal bones is an example of a condyloid joint.

(5) A saddle joint enables flexion, extension, and other movements, but no rotation. In the hand, the thumb’s saddle joint (in between the very first metacarpal and the trapezium) lets the thumb changeover the palm, making it opposable.

Further Reading:  Altruism in Animals [with MCQs]

(6) The ball-and-socket joint is a freely moving joint that can rotate on any axis. The hip and shoulder joints are examples of ball and socket joints.

Importance of Joints

The joints help us to rotate our shoulder, bend our knees and elbows, rotate our neck, and more. A joint is a point where two bones meet to supply a framework that permits movement.

MCQs about Joints

  • What is the key attribute that distinguishes living organisms from non-living ones in terms of mobility?
    • A. Wings
    • B. Bones and muscles
    • C. Cilia
    • D. Flagella
    • Answer: B
  • How many bones do adults have in their body, and what is the estimated number of joints in the body?
    • A. 270 bones, 250 joints
    • B. 206 bones, 300 joints
    • C. 250 bones, 350 joints
    • D. 206 bones, 250 joints
    • Answer: D
  • What are sesamoids, and where is the largest sesamoid located in the human body?
    • A. Immovable joints, in the skull
    • B. Bones embedded in tendons, in the patella (kneecap)
    • C. Cartilaginous joints, in the spine
    • D. Fibrous joints, in the jaw
    • Answer: B
  • Which type of joint is described as immovable or fibrous and provides an example of bones in close contact with no motion?
    • A. Amphiarthroses
    • B. Synovial joints
    • C. Synarthroses
    • D. Diarthroses
    • Answer: C
  • What are the three kinds of fibrous joints, and what is an example of a syndesmosis?
    • A. Sutures, gomphoses, syndesmosis; distal joint between tibia and fibula
    • B. Synchondrosis, syndesmosis, symphysis; joints of the spine
    • C. Sutures, symphysis, pivot joint; elbow joint
    • D. Syndesmosis, gomphoses, synovial joint; wrist joint
    • Answer: A
  • What is another term for slightly movable joints, and what is a good example of this type of joint in the human body?
    • A. Synovial joints, knee joint
    • B. Amphiarthroses, vertebrae of the spine
    • C. Diarthroses, shoulder joint
    • D. Symphysis, hip joint
    • Answer: B
  • Name the two types of cartilaginous joints and provide an example for each.
    • A. Synchondrosis, elbow joint; symphysis, hip joint
    • B. Synovial joint, knee joint; symphysis, hip joint
    • C. Synchondrosis, ribs and sternum; symphysis, intervertebral discs
    • D. Syndesmosis, tibia and fibula; symphysis, shoulder joint
    • Answer: C
  • What are diarthroses also known as, and which type of joint is the most common in the human body?
    • A. Amphiarthroses, pivot joints
    • B. Synarthroses, fibrous joints
    • C. Diarthroses, synovial joints
    • D. Symphysis, cartilaginous joints
    • Answer: C
  • Name the six types of synovial joints and provide an example for each.
    • A. Hinge joint, hip joint; pivot joint, elbow joint; saddle joint, shoulder joint; ball-and-socket joint, wrist joint; gliding joint, knee joint; condyloid joint, ankle joint
    • B. Gliding joint, intervertebral joints; hinge joint, elbow joint; pivot joint, head joints; condyloid joint, wrist joint; saddle joint, thumb joint; ball-and-socket joint, hip joint
    • C. Hinge joint, finger joints; pivot joint, shoulder joint; saddle joint, ankle joint; ball-and-socket joint, knee joint; gliding joint, wrist joint; condyloid joint, hip joint
    • D. Gliding joint, wrist and ankle bones; hinge joint, elbow joint; pivot joint, neck joints; condyloid joint, knee joint; saddle joint, thumb joint; ball-and-socket joint, hip joint
    • Answer: D
  • How do joints help in terms of movement in the human body?
    • A. By providing structure and shape
    • B. By allowing rotation of the head
    • C. By connecting bones with fibers of connective tissue
    • D. By allowing flexibility and movement at points where two bones meet
    • Answer: D
  • What distinguishes living organisms from non-living ones in terms of mobility, and what provides structure and shape to the human body?
    • A. Muscles; Synovial joints
    • B. Bones and muscles; Skeletal system
    • C. Wings; Fibrous joints
    • D. Cilia; Cartilaginous joints
    • Answer: B
  • How are sesamoids different from other bones, and what is the largest sesamoid in the human body?
    • A. Embedded in muscles, patella (kneecap)
    • B. Connected to other bones, vertebral column
    • C. Immovable, hip joint
    • D. Floating in joints, elbow joint
    • Answer: A
  • Which type of joint allows only limited movement and is also known as cartilaginous joints?
    • A. Amphiarthroses
    • B. Synovial joints
    • C. Synarthroses
    • D. Diarthroses
    • Answer: A
  • What are the characteristics of a synchondrosis, and where is it found in the human body?
    • A. Immovable cartilaginous joint; Joint between the first pair of ribs and the sternum
    • B. Freely movable joint; Wrist joint between radius and carpal bones
    • C. Joint with ligament connection; Distal joint between tibia and fibula
    • D. Compressible fibrocartilaginous pad; Joint between vertebrae connected by intervertebral discs
    • Answer: A
  • Which type of joint is responsible for circular movement, flexion, and extension, and what is an example of this joint in the human body?
    • A. Condyloid joint; Elbow joint
    • B. Saddle joint; Hip joint
    • C. Pivot joint; Head joints
    • D. Hinge joint; Wrist joint between radius and carpal bones
    • Answer: A
  • What is the unique characteristic of a saddle joint, and where is it found in the human body?
    • A. Allows rotation; Knee joint
    • B. Enables circular movement; Wrist joint
    • C. Permits flexion, extension, but no rotation; Thumb’s saddle joint
    • D. Moves on a single plane; Ankle joint
    • Answer: C
  • Which type of joint is freely moving and can rotate on any axis, and provide examples of such joints in the human body?
    • A. Ball-and-socket joint; Knee and elbow joints
    • B. Gliding joint; Intervertebral joints and bones of the wrists
    • C. Hinge joint; Elbow and finger joints
    • D. Saddle joint; Thumb joint and hip joint
    • Answer: A
  • How do joints contribute to the movement in terms of rotating the neck, bending knees and elbows, and more?
    • A. By allowing only limited movement
    • B. By connecting bones with fibers of connective tissue
    • C. By providing a framework for movement
    • D. By forming immovable joints
    • Answer: C
  • What is the primary function of synovial joints, and what substance allows the efficient movement of these joints?
    • A. To provide structure and shape; Synovial fluid
    • B. To form immovable joints; Fibrous tissue
    • C. To connect bones with ligaments; Cartilage
    • D. To allow freely movable joints; Synovial membrane
    • Answer: A
  • Which type of joint is formed by bones in close contact with no motion, and what is a specific example of this joint in the human body?
    • A. Diarthroses; Knee joint
    • B. Synarthroses; Joints of the skull
    • C. Amphiarthroses; Hip joint
    • D. Symphysis; Elbow joint
    • Answer: B
  • What is the significance of joints in terms of survival and biological requirements in living organisms?
    • A. Provide shape to the skeletal system
    • B. Essential for locomotion and movement
    • C. Form synovial fluid for joint lubrication
    • D. Fuse together during growth
    • Answer: B
  • How many bones do babies start with, and what is the estimated number of joints in the adult human body?
    • A. 206 bones, 300 joints
    • B. 270 bones, 250 joints
    • C. 350 bones, 206 joints
    • D. 270 bones, between 250 and 350 joints
    • Answer: D
Further Reading:  Multiple Choice Questions - Phylum Porifera

 

FAQs: Definition, Classification, and Importance of Joints

  1. Why are bones and muscles considered significant for locomotion and movement in living organisms?
    • Living organisms need to adjust to their environment and fulfill biological requirements such as food, self-preservation, and mating. Bones and muscles aid in mobility.
  2. What is the role of joints in the skeletal system?
    • Joints provide the means for movement, allowing bones to articulate and facilitating various types of motion.
  3. How many bones do babies start with, and how does this number change in adults?
    • Babies start with about 270 bones, and some of these bones fuse together during growth, resulting in adults having approximately 206 bones.
  4. What are sesamoids, and where is the largest sesamoid located in the human body?
    • Sesamoids are bones embedded in tendons, and the largest sesamoid is the patella (kneecap).
  5. Can the number of sesamoids vary from person to person?
    • Yes, the number of sesamoids can differ from person to person.
  6. How are synarthroses (immovable) joints defined, and can you provide an example?
    • Synarthroses are fixed or fibrous joints, and an example is the close contact of bones in the skull, which allows no motion.
  7. What are the three types of fibrous joints, and can you explain a syndesmosis?
    • The three types are sutures, gomphoses, and syndesmosis. Syndesmosis is a joint where a ligament connects two bones, permitting slight motion, as seen in the distal joint between the tibia and fibula.
  8. What characterizes amphiarthroses (slightly movable) joints, and can you provide an example?
    • Amphiarthroses, also known as cartilaginous joints, allow limited movement due to a secure connection between two or more bones. An example is the vertebrae of the spine.
  9. Name the two types of cartilaginous joints and provide examples for each.
    • Synchondrosis, an immovable joint like the first pair of ribs and the sternum; symphysis, a joint with a compressible fibrocartilaginous pad like the pubic symphysis and intervertebral discs.
  10. What is the distinguishing feature of diarthroses (freely movable) joints, and can you provide examples of synovial joints?
    • Diarthroses, or synovial joints, have synovial fluid allowing efficient movement. Examples include the knee and shoulder joints.
  11. List the six types of synovial joints and provide examples for each.
    • Gliding joints (intervertebral joints, wrists, and ankles), hinge joints (elbow, finger joints), pivot joint (atlas and axis for head rotation), condyloid joint (wrist), saddle joint (thumb), and ball-and-socket joint (hip, shoulder).
  12. How do joints contribute to the movement of the human body, and why are they considered essential?
    • Joints allow rotation, bending, and various movements, providing a framework that permits movement, making them essential for daily activities and survival.
Further Reading:  Glycoproteins Definition, Lysosomal Metabolic Process and Functions

Summary: Definition, Classification, and Importance of Joints

The tutorial on the Definition, Classification, and Importance of Joints provides a comprehensive understanding of the crucial role joints play in the human skeletal system and overall mobility. It begins by highlighting the significance of locomotion in living organisms and the key elements involved, namely bones and muscles.

Overview

The tutorial delves into the concept of joints, also known as articulations or articular surfaces, which serve as connections between bones. The classification of joints based on structure and function is explored, accompanied by insights into the skeletal system’s evolution from infancy to adulthood.

Inclusion of Sesamoids

The tutorial discusses the inclusion of sesamoids, bones embedded in tendons, and their variation in number among individuals.

Classification of Joints

The classification of joints includes:

  • Synarthroses (immovable): Fixed or fibrous joints, exemplified by the bones of the skull.
  • Types of Fibrous Joints: Exploring sutures, gomphoses, and syndesmosis.
  • Amphiarthroses (slightly movable): Also known as cartilaginous joints, illustrated by the vertebrae of the spine.
  • Types of Cartilaginous Joints: Synchondrosis and symphysis, exemplified by joints like the first pair of ribs and the sternum.
  • Diarthroses (freely movable): Known as synovial joints, common in the human body, including examples like the knee and shoulder.

Types of Synovial Joints

The tutorial details six types of synovial joints:

  1. Gliding joints
  2. Hinge joints
  3. Pivot joints
  4. Condyloid joints
  5. Saddle joints
  6. Ball-and-socket joints

Importance of Joints

The importance of joints in facilitating various movements, including shoulder rotation, knee and elbow bending, and neck rotation, is emphasized. Joints act as pivotal meeting points between bones, providing a framework for movement essential for daily activities and survival.

Conclusion

In conclusion, this tutorial serves as a comprehensive guide to understanding the definition, classification, and importance of joints, shedding light on the intricate mechanisms that enable human mobility and the vital role joints play in maintaining a functional and adaptable skeletal system.

You may also like to learn: