Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

6. Bones & Skeletal Tissue

Microscopic Anatomy of Bones - Bone Cells

Anatomy & Physiology

6. Bones & Skeletal Tissue

Microscopic Anatomy of Bones - Bone Cells

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3:12 minutes

Problem 22

Textbook Question

Noah Beckenstein went to weight-lifting camp in the summer between seventh and eighth grade. He noticed that the camp trainer put tremendous pressure on him and his friends to improve their strength. After an especially vigorous workout, Noah's arm felt extremely sore and weak around the elbow. He went to the camp doctor, who took X rays and then told him that the injury was serious, for the 'end of his upper arm bone was starting to twist off.' What had happened? Could the same thing happen to Noah's 23-year-old sister, Karen, who was also starting a program of weight lifting? Why or why not?

Verified step by step guidance

Step 1: Understand the anatomy of the upper arm and elbow joint. The upper arm bone, known as the humerus, connects to the forearm bones (radius and ulna) at the elbow joint. The distal end of the humerus includes structures like the epicondyles and the trochlea, which are critical for joint stability and muscle attachment.

Step 2: Recognize the condition described in the problem. The phrase 'end of his upper arm bone was starting to twist off' likely refers to an epiphyseal injury. In growing children and adolescents, the ends of long bones have growth plates (epiphyseal plates), which are areas of cartilage that allow the bone to grow. These plates are weaker than the surrounding bone and are susceptible to injury under excessive stress.

Step 3: Explain why Noah is at risk. During adolescence, growth plates are still active and not fully ossified, making them more vulnerable to damage from intense physical activity, such as weight lifting. Excessive strain can cause the growth plate to fracture or separate, leading to serious complications like deformity or impaired growth.

Step 4: Compare Noah's situation to his 23-year-old sister, Karen. By the age of 23, Karen's growth plates would have fully ossified and fused, as bone growth typically ceases after puberty. This means her bones are structurally stronger and less prone to the type of injury Noah experienced. However, she could still sustain other types of injuries, such as tendon or ligament damage, if she overexerts herself during weight lifting.

Step 5: Conclude with preventive measures. For adolescents like Noah, it is crucial to avoid excessive strain on the growth plates by using proper technique, appropriate weights, and allowing adequate rest between workouts. Adults like Karen should also follow safe weight-lifting practices to prevent other types of musculoskeletal injuries.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Muscle Strain and Overuse Injuries

Muscle strain occurs when muscles are overstretched or torn, often due to excessive force or repetitive use. In weight lifting, improper technique or lifting weights that are too heavy can lead to overuse injuries, which may manifest as soreness, weakness, or even more severe conditions like tendon tears or fractures. Understanding the mechanics of muscle strain is crucial for recognizing the risks associated with intense physical training.

Growth Plates and Skeletal Development

Growth plates are areas of developing cartilage tissue near the ends of long bones in children and adolescents. These plates are crucial for bone growth and can be vulnerable to injury, especially during intense physical activities like weight lifting. If an injury occurs to the growth plate, it can lead to long-term complications in bone development, making it essential to consider the age and physical maturity of individuals engaging in such activities.

Age-Related Differences in Injury Risk

Injury risk can vary significantly between adolescents and adults due to differences in physical development, muscle strength, and bone density. While Noah, being younger, may have more vulnerable growth plates, his 23-year-old sister, Karen, has fully developed bones and muscles, which may make her less susceptible to certain types of injuries. However, she can still experience injuries related to overtraining or improper technique, highlighting the importance of safe practices in weight lifting for all ages.

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