Lecture 9

Question 1

How do skeletal muscles cause movement at synovial joints?

Answer 1

By attaching to bones via tendons and shortening to create movement.

Question 2

What determines the function of a muscle?

Answer 2

The length, number, and arrangement of muscle fibers.

Question 3

What are the three classes of levers in the body?

Answer 3

First-class (stabilizes joint position), second-class (overcomes heavy loads), and third-class (large range of movement and speed).

Question 4

What are the three types of muscle contractions?

Answer 4

Concentric (muscle shortens), eccentric (muscle lengthens), and isometric (muscle length stays the same).

Question 5

What are the roles of agonist, antagonist, stabilizer, and neutralizer muscles?

Answer 5

Agonist creates movement, antagonist opposes movement, stabilizer holds a joint still, neutralizer prevents unwanted movement.

Question 6

What is the origin, insertion, and movement of the biceps brachii?

Answer 6

Origin: Scapula. Insertion: Radial tuberosity. Movement: Flexion at the shoulder and elbow, supination at the radioulnar joints.

Question 7

What is the origin, insertion, and movement of the triceps brachii?

Answer 7

Origin: Scapula and humerus. Insertion: Olecranon process of ulna. Movement: Extension at the shoulder and elbow.

Question 8

What is the origin, insertion, and movement of the deltoid muscle?

Answer 8

Origin: Scapula and clavicle. Insertion: Deltoid tuberosity. Movement: Shoulder flexion (anterior fibers), abduction (lateral fibers), and extension (posterior fibers).

Question 9

What is the origin, insertion, and movement of the iliopsoas?

Answer 9

Origin: Iliac fossa and lumbar vertebrae. Insertion: Femur. Movement: Hip flexion.

Question 10

What is the origin, insertion, and movement of the gluteus maximus?

Answer 10

Origin: Ilium and sacrum. Insertion: Femur. Movement: Hip extension.

Question 11

What is the origin, insertion, and movement of the quadriceps femoris?

Answer 11

Origin: Ilium (rectus femoris) and femur (vastus muscles). Insertion: Tibial tuberosity. Movement: Hip flexion (rectus femoris) and knee extension.

Question 12

What is the origin, insertion, and movement of the hamstrings?

Answer 12

Origin: Ischium and femur (biceps femoris). Insertion: Tibia (semimembranosus and semitendinosus) and fibula (biceps femoris). Movement: Hip extension and knee flexion/rotation.

Question 13

What is the origin, insertion, and movement of the tibialis anterior?

Answer 13

Origin: Tibia. Insertion: Tarsals. Movement: Ankle dorsiflexion.

Question 14

What is the origin, insertion, and movement of the triceps surae (gastrocnemius and soleus)?

Answer 14

Origin: Femur condyles (gastrocnemius) and tibia/fibula (soleus). Insertion: Calcaneus via Achilles tendon. Movement: Knee flexion (gastrocnemius) and ankle plantarflexion.