Question

88
chapter 7 muscular system
1.
2.

1. rhomboideus major
2. deltoid
3. infraspinatus
4. teres minor
5. teres major
6. gluteus maximus
7. latissimus dorsi

10.
11.
12.
13.
14.
15.
16.
17.
18.
19
20
21
22
23
24
h. list the factors that affect a muscle contraction.
stimulus strength
muscle fiber
fatigue
temperature
age

Explanation:

First, identify the unlabeled/incorrectly labeled muscles on the posterior human muscular diagram, then confirm standard factors affecting muscle contraction.

1. Correct muscle labels for unnumbered/incorrect lines:

• 1: Occipitalis (posterior scalp muscle)
• 2: Sternocleidomastoid (posterior neck portion)
• 3: *Correct: Sternocleidomastoid (posterior neck, the handwritten label is misspelled)
• 4: *Correct: Deltoid (shoulder muscle)
• 5: *Correct: Infraspinatus (posterior shoulder muscle)
• 6: *Correct: Teres minor (posterior upper arm muscle, misspelled)
• 7: *Correct: Teres major (posterior upper arm muscle, misspelled)
• 9: *Correct: Latissimus dorsi (posterior back muscle, misspelled)

1. Label the numbered (14-24) muscles:

• 14: Supraspinatus (posterior shoulder, above infraspinatus)
• 15: Infraspinatus (matches handwritten label 5, posterior shoulder)
• 16: Teres minor (matches handwritten label 6, posterior upper arm)
• 17: Triceps brachii (posterior upper arm muscle)
• 18: Gluteus medius (upper buttock, above gluteus maximus)
• 19: Biceps femoris (posterior thigh, hamstring muscle)
• 20: Semitendinosus (posterior thigh, hamstring muscle)
• 21: Semimembranosus (posterior thigh, hamstring muscle)
• 22: Hamstring group (collective term for 19-21)
• 23: Gastrocnemius (calf muscle, upper portion)
• 24: Soleus (calf muscle, under gastrocnemius)
• 11: Biceps femoris (posterior thigh, lateral)
• 12: Gastrocnemius (calf muscle, upper)
• 13: Achilles tendon (connects calf to heel)

1. Validate factors affecting muscle contraction: standard, evidence-based factors include the handwritten points (corrected for clarity) plus additional key factors.

Answer:

Muscle Label Corrections & Completions:

1. Occipitalis
2. Sternocleidomastoid (posterior)
3. Sternocleidomastoid (corrected spelling)
4. Deltoid (correct)
5. Infraspinatus (correct)
6. Teres minor (corrected spelling)
7. Teres major (corrected spelling)
8. Gluteus maximus (correct)
9. Latissimus dorsi (corrected spelling)
10. Adductor magnus (posterior thigh)
11. Biceps femoris
12. Gastrocnemius
13. Achilles tendon
14. Supraspinatus
15. Infraspinatus
16. Teres minor
17. Triceps brachii
18. Gluteus medius
19. Biceps femoris
20. Semitendinosus
21. Semimembranosus
22. Hamstring group (19-21)
23. Gastrocnemius
24. Soleus

Factors Affecting Muscle Contraction:

• Stimulus strength (threshold & recruitment)
• Muscle fiber type (fast-twitch vs slow-twitch)
• Muscle fatigue (lactic acid buildup, energy depletion)
• Muscle temperature (warmer muscles contract more efficiently)
• Age (muscle mass/function declines with age)
• Additional key factors: Muscle length-tension relationship, availability of ATP/oxygen, hormone levels (e.g., testosterone), hydration status