Types of Joints in Anatomy

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Questions and Answers

What is the primary function of muscles?

Stabilizing body posture

Transmitting nerve impulses

Contraction and shortening (correct)

Regulating body temperature

Which type of muscle cells exhibit obvious striations?

Smooth muscle cells

All muscle types

Cardiac muscle cells

Skeletal muscle fibers (correct)

What term describes muscle fibers in terms of their shape?

Cuboidal

Elongated (correct)

Spherical

Fractal

What is the connective sheath surrounding each muscle fiber called?

Endomysium Signup and view all the answers

What is the role of epimysium in skeletal muscles?

To cover the entire muscle Signup and view all the answers

Which type of muscle contraction is voluntary?

Skeletal muscle contraction Signup and view all the answers

Why is connective tissue necessary at each layer of skeletal muscle?

To provide strength and support to the muscle Signup and view all the answers

Skeletal muscle fibers are packaged into which structure?

Fascicles Signup and view all the answers

What type of joint is formed when the bone ends are connected by cartilage?

Cartilaginous Joint Signup and view all the answers

Which of the following is a characteristic of all synovial joints?

Articular cartilage covers the ends of the bones Signup and view all the answers

What is the function of bursae in synovial joints?

Reduce friction between structures Signup and view all the answers

Which type of cartilaginous joint allows for slight movement?

Amphiarthrotic Joint Signup and view all the answers

What protects and encloses the joint cavity in synovial joints?

Fibrous articular capsule Signup and view all the answers

In syndesmoses, the fibers connecting the bones are generally characterized as:

Longer than those of sutures Signup and view all the answers

The type of joint between the first ribs and the sternum is classified as:

Synarthrotic Joint Signup and view all the answers

What is contained within the joint cavity of synovial joints?

Synovial fluid Signup and view all the answers

What is the main purpose of the microfracture surgical technique?

To stimulate the growth of new cartilage Signup and view all the answers

In autologous chondrocyte implantation (ACI), what is the primary step before implantation?

Culturing cartilage cells in a lab Signup and view all the answers

What is the primary function of intercostal muscles?

Elevate the ribs during breathing Signup and view all the answers

Which treatment option is used specifically for complete ligament tears?

Surgical ligament reconstruction Signup and view all the answers

What happens to ATP levels in the body after death in relation to rigor mortis?

ATP production ceases completely Signup and view all the answers

Which type of joint allows for the most movement?

Diarthroses Signup and view all the answers

In the context of the sliding filament theory, what role does ATP play in muscle contraction?

It is required for the detachment of myosin heads from actin filaments Signup and view all the answers

What are fibrous joints primarily characterized by?

Fibrous tissue connections Signup and view all the answers

What technique involves taking healthy cartilage and bone from a non-weight-bearing area of the patient’s knee?

Osteochondral Autograft Transplantation Signup and view all the answers

Where are immovable and slightly movable joints primarily located?

In the axial skeleton Signup and view all the answers

For which type of injuries is a combination of bracing and physical therapy most appropriate?

Minor ligament injuries Signup and view all the answers

Which type of joint is an example of amphiarthrotic movement?

Intervertebral discs Signup and view all the answers

What is NOT a function of joints or articulations?

Facilitating blood circulation Signup and view all the answers

What characterizes rigor mortis as a post-mortem condition?

Stiffening of muscles Signup and view all the answers

Which intercostal muscles are primarily responsible for exhalation?

Internal intercostal muscles Signup and view all the answers

Which classification focuses on the amount of movement allowed by a joint?

Functional classification Signup and view all the answers

What is the primary energy source directly used for muscle activity?

ATP Signup and view all the answers

Which pathway primarily occurs in the mitochondria and requires oxygen?

Aerobic Respiration Signup and view all the answers

What contributes to muscle fatigue during prolonged activity?

Inadequate oxygen supply Signup and view all the answers

What is the result of anaerobic glycolysis when oxygen delivery is insufficient?

Lactic Acid Formation Signup and view all the answers

Which type of muscle contraction results in movement and muscle shortening?

Isotonic Contraction Signup and view all the answers

What is muscle tone primarily characterized by?

Continuous partial contractions of muscle fibers Signup and view all the answers

Which situation typically leads to the buildup of lactic acid?

High intensity activity without enough oxygen Signup and view all the answers

What does the process of direct phosphorylation primarily utilize?

Creatine Phosphate Signup and view all the answers

What describes isometric contractions?

Muscle tension increases but length remains constant Signup and view all the answers

How does inadequate oxygen supply affect muscle activity?

Increases lactic acid production causing fatigue Signup and view all the answers

Study Notes

Joint Types

Syndesmoses are fibrous joints where the connecting fibers are longer than those of sutures, for example, the distal ends connecting tibia and fibula.
Cartilaginous joints connect bone ends with cartilage.
- Amphiarthrotic cartilaginous joints are slightly movable, like the pubic symphysis of the pelvis and intervertebral joints of the spinal column.
- Synarthrotic cartilaginous joints are immovable, like hyaline-cartilage epiphyseal plates of growing long bones and cartilaginous joints between first ribs and sternum.
Synovial joints are freely movable joints where the articulating bone ends are separated by a joint cavity containing synovial fluid.
- They account for all joints in the limbs.
- Characteristics of Synovial Joints:
  - Articular cartilage (hyaline cartilage) covers the ends of the bones.
  - Fibrous articular capsule encloses the joint.
  - Joint cavity contains synovial fluid.
  - Reinforcing ligaments strengthen the fibrous capsule.
- Bursae are flattened fibrous sacs lined with synovial membrane and containing synovial fluid. They are common where ligaments, muscles, skin, tendons, or bones rub together.

Muscles

Muscle function is primarily contraction/shortening.
Muscles are responsible for essentially all body movement.
Similarities between skeletal and smooth muscle cells:
- Elongated shape, referred to as muscle fibers.
- Contain two types of myofilaments.
- "Myo-" means muscle.
Skeletal muscle fibers are packaged into organs called skeletal muscles:
- Attached to bones or skin (facial muscles).
- Long, cylindrical, multinucleate cells with striations.
- Voluntary contraction (only muscle under conscious control).
- No rhythmic contraction, range from slow to fast.

Connective Tissues in Skeletal Muscles

Connective tissue wrappings provide strength and support to skeletal muscles.
- Endomysium encloses each muscle fiber.
- Perimysium wraps sheathed fibers together to form fascicles.
- Epimysium covers the entire muscle and blends into tendons or aponeuroses.

Energy for Muscle Contractions

ATP is the only energy source that can be used directly to power muscle activity.
Three pathways for ATP regeneration:
- Direct Phosphorylation of ADP by creatine phosphate:
  - Creatine phosphate (CP) is a high-energy molecule found in muscle fibers.
  - When ATP is depleted, CP transfers a phosphate group to ADP.
- Aerobic Respiration:
  - Occurs in mitochondria.
  - Breaks down glucose into carbon dioxide and water.
  - Slow process that requires continuous oxygen and nutrients, high ATP yield.
- Anaerobic glycolysis and lactic acid formation:
  - Initial steps of glucose breakdown occur in the cytosol (glycolysis).
  - Produces small amounts of ATP.
  - If oxygen is insufficient, pyruvic acid is converted to lactic acid.
  - Lactic acid can cause muscle soreness.
  - Produces much less ATP than aerobic respiration, but is faster.

Muscle Fatigue

Muscle fatigue occurs when a muscle is unable to contract even though it is still being stimulated.
Causes of muscle fatigue:
- Oxygen debt: The muscle is not receiving enough oxygen to meet its demands.
- Lactic acid buildup: Increasing acidity and lack of ATP cause the muscle to stop contracting.

Types of Muscle Contractions

Isotonic contractions: Muscle shortens and movement occurs (bending knee, smiling).
Isometric contractions: Muscle tension increases, but no movement occurs (lifting a heavy object).

Muscle Tone

Muscle tone is continuous partial contractions of a muscle.
Even when relaxed, some fibers are contracting, keeping the muscle firm and healthy.

Muscle Rules

Antagonistic muscles: Oppose or reverse the action of another muscle.
Synergistic muscles: Assist the prime mover by adding extra force to a movement.
Fixator muscles: Stabilize the origin of a prime mover to prevent movement.

Intercostal Muscles

Three layers: external, internal, innermost intercostal muscles.
Origin (O): Ribs 1-11.
Insertion (I): Ribs 2-12.
Action (A): Raise the ribs, expand the chest cavity during breathing.

Joints

All bones in the body form at least one joint with another bone.
Functions of joints:
- Hold bones together.
- Allow mobility to the skeleton.

Classification of Joints

Functional classification: Based on the amount of movement allowed.
- Synarthroses: Immovable joints.
- Amphiarthroses: Slightly movable joints.
- Diarthroses: Freely movable joints.
Structural classification: Based on the type of tissue that connects the bones.
- Fibrous joints: Bones are united by fibrous tissue (immovable).
- Cartilaginous joints: Bones are united by cartilage (slightly movable).
- Synovial joints: Bones are separated by a joint cavity containing synovial fluid (freely movable).

Fibrous Joints

Sutures of the skull are examples of fibrous joints.
- Bone edges interlock and are bound by connective tissue fibers.
- No movement allowed.
Microfracture is a surgical technique to stimulate cartilage growth.
Autologous Chondrocyte Implantation (ACI) involves culturing cartilage cells and implanting them back into the damaged area.
Osteochondral Autograft Transplantation (OAT) involves transplanting healthy cartilage and underlying bone from a non-weight-bearing area.

Ligament Repair

Surgical Ligament Reconstruction: Damaged ligament is replaced with a graft.
Ligament Repair (Direct Suturing): Partial tears are sutured back together.
Bracing and Rehabilitation: Bracing and physical therapy is often used for minor injuries.

Rigor Mortis and the Sliding Filament Theory

Rigor mortis: Stiffening of muscles after death.
Mechanism of Rigor Mortis:
- ATP depletion: ATP production ceases, and myosin heads cannot detach from actin filaments.
- Myosin binding: Without ATP, myosin remains bound to actin, resulting in muscle stiffness.
- Muscle relaxation: Muscle relaxation requires ATP to detach myosin heads.
- Cellular breakdown: Eventually, muscle proteins break down, and rigor mortis resolves.
The sliding filament theory explains how muscle contraction occurs through the interaction of actin and myosin filaments.

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Description

Explore the various types of joints in human anatomy, including syndesmoses, cartilaginous, and synovial joints. This quiz covers their characteristics, movements, and examples to deepen your understanding of how our bodies are structured. Test your knowledge on joint classifications and their functions.