Unit 9 & 10 Skeletal and Muscular systems1

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Questions and Answers

Which function of the skeletal system primarily involves supporting soft tissues?

Support (correct)

Blood Cell Production

Protection

Mineral and Fat Storage

Which type of bone cell is responsible for breaking down the bone matrix?

Chondrocytes

Osteoclasts (correct)

Osteocytes

Osteoblasts

What type of bone is characterized by being organized into osteons and making up the majority of the diaphysis in long bones?

Trabecular Bone

Compact Bone (correct)

Spongy Bone

Sesamoid Bone

Which shape classification does the femur belong to?

Long Bone Signup and view all the answers

What is the primary role of collagen in bone tissue?

Provide flexibility and strength Signup and view all the answers

Which of the following bones is classified as a short bone?

Carpals Signup and view all the answers

What type of bone primarily consists of red bone marrow?

Spongy Bone Signup and view all the answers

Which of the following is NOT a part of the axial skeletal system?

Humerus Signup and view all the answers

Which type of tissue is primarily involved in fibrous joints?

Dense irregular connective tissue Signup and view all the answers

What is the primary function of the spine?

Support the head Signup and view all the answers

What type of movement is primarily associated with hinge joints?

Flexion and extension Signup and view all the answers

Which group of ribs are referred to as true ribs?

Ribs 1 to 7 Signup and view all the answers

What type of fracture is characterized by a break that does not disturb the skin?

Closed fracture Signup and view all the answers

Which of the following best describes synovial joints?

Highly movable joints with a capsule that contains synovial fluid Signup and view all the answers

Which part of the skeleton is classified as the appendicular skeleton?

Shoulders and limbs Signup and view all the answers

What is the primary function of the synovial membrane?

To secrete synovial fluid for lubrication Signup and view all the answers

Which synovial joint allows for the greatest range of motion?

Ball-and-socket joint Signup and view all the answers

What is a characteristic of rickets?

Weakened, softer bones Signup and view all the answers

Which classification of joints allows for the most movement?

Freely Movable (Diarthrosis) Signup and view all the answers

What type of joint is characterized by an oval projection fitting into an oval cavity?

Condyloid joint Signup and view all the answers

Which movement decreases the angle between two bones?

Flexion Signup and view all the answers

What is the main role of joints?

Permit movement and provide stability Signup and view all the answers

What type of joint primarily facilitates rotation around a bone's longitudinal axis?

Pivot joint Signup and view all the answers

What do false ribs do?

Articulate indirectly with the sternum Signup and view all the answers

What is the primary characteristic of skeletal muscle?

Striated and multinucleated Signup and view all the answers

Which term describes the end of a muscle attached to the stationary bone?

Origin Signup and view all the answers

What type of muscle is responsible for involuntary movements within the walls of hollow organs?

Smooth muscle Signup and view all the answers

During elbow flexion, which muscle acts as the agonist?

Biceps brachii Signup and view all the answers

What happens to muscle cells during hypertrophy?

They get larger Signup and view all the answers

What is the role of a synergist muscle during movement?

Assists the agonist Signup and view all the answers

Which characteristic is associated with cardiac muscle?

1-3 nuclei and intercalated discs Signup and view all the answers

What is the cytoplasm of a muscle fiber called?

Sarcoplasm Signup and view all the answers

What initiates the release of acetylcholine at the neuromuscular junction?

The arrival of an action potential at the axon terminal Signup and view all the answers

Which structural characteristic defines skeletal muscle fibers?

Multinucleated configuration Signup and view all the answers

In the cross-bridge cycle, what action occurs after calcium binds to troponin?

Tropomyosin moves to expose actin binding sites Signup and view all the answers

What is the major neurotransmitter involved in signaling at the neuromuscular junction?

Acetylcholine Signup and view all the answers

What role do transverse tubules (T tubules) play in skeletal muscle contraction?

Conduct action potentials into the muscle fiber Signup and view all the answers

Which ion is primarily responsible for triggering the release of calcium ions from the sarcoplasmic reticulum during muscle contraction?

Calcium (Ca²⁺) Signup and view all the answers

What event directly results from the binding of acetylcholine to muscle fiber receptors?

Opening of sodium ion channels Signup and view all the answers

What is the consequence of myosin heads performing a power stroke during muscle contraction?

Sliding of thick and thin filaments across each other Signup and view all the answers

Study Notes

Skeletal System Function

Provides support and protection for soft tissues.
Shields vital organs like the brain, heart, and lungs.
Acts as levers for muscles, enabling movement at joints.
Stores minerals like calcium and phosphorus, and fat.
Produces blood cells in red bone marrow.

Bone Tissue Composition

Consists of cells and an extracellular matrix of proteins (collagen) and minerals.
Collagen fibers (25%) and water (25%) provide flexibility and strength.
Minerals provide strength against stress.

Types of Bone

Compact Bone:
- Organized osteons.
- Forms the bulk of long bone diaphysis.
- Provides protection, support, and resistance to stress.
Spongy Bone:
- Also called trabecular bone.
- Less organized structure.
- Found in short, flat, irregular bones, and epiphyses.
- Lighter weight.
- Contains red bone marrow.
- Trabeculae follow lines of stress.

Bone Classification

Long Bones:
- Long, with expanded ends (e.g., femur, humerus).
- Growth occurs at the epiphyseal growth plate.
Short Bones:
- Cube-shaped (e.g., carpals, tarsals).
Sesamoid Bones:
- Small, round bones embedded in tendons (e.g., patella).
Flat Bones:
- Thin, broad surfaces (e.g., ribs, sternum, skull bones).
- Protect internal organs.
Irregular Bones:
- Variety of shapes (e.g., vertebrae, some facial bones).

Axial Skeleton

Consists of 80 bones.
Includes the skull, vertebrae, sternum, and ribs.

Appendicular Skeleton

Attaches upper and lower limbs to the axial skeleton.
Includes 126 bones.
Contains bones of the pectoral girdle, upper limbs, pelvic girdle, and lower limbs.

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