16 Questions
What is the function of the 'M' line in the myofibril?
To hold together the thin filaments in the 'I' band
What is the main reason for the striated appearance of the myofibril?
The arrangement of actin and myosin proteins
What is the sarcomere, as mentioned in the text?
The portion of myofibril between two successive 'Z' lines
Which type of muscle fibers contain plenty of mitochondria for ATP production?
Red fibers
What is the role of actin and myosin in muscle fibers?
Myosin generates movement, while actin provides structural support
Which type of muscle fibers depend on anaerobic process for energy?
White fibers
How many cranial bones are there in the human skull?
8
What is the primary role of the skeletal system in the body?
Supporting the body
Which bone is present at the base of the buccal cavity and is included in the skull?
Hyoid bone
How many bones make up the axial skeleton in human beings?
80 bones
How many skeletal elements form the front part of the skull in the facial region?
14
What is the name of the bone that articulates with the occipital condyles?
Atlas
What causes the shortening of the sarcomere during muscle contraction?
Pulling of the actin filaments towards the center of the A band
What is responsible for the accumulation of lactic acid in muscles during repeated activation?
Anaerobic breakdown of glycogen
What is the role of myoglobin in muscles?
Storing oxygen
What leads to the return of 'Z' lines back to their original position, i.e., relaxation?
Pumping of Ca++ ions into the sarcoplasmic cisternae
Study Notes
Muscle Structure and Function
- The 'M' line in the myofibril is where myosin thick filaments are anchored.
- The striated appearance of the myofibril is due to the regular arrangement of sarcomeres.
- A sarcomere is the functional unit of the myofibril, containing actin and myosin filaments.
- Oxidative muscle fibers contain plenty of mitochondria for ATP production.
- Actin and myosin filaments slide past each other, causing muscle contraction.
- Anaerobic muscle fibers depend on anaerobic processes for energy.
Skeletal System
- The human skull consists of 22 cranial bones.
- The primary role of the skeletal system is to provide support and protection for the body.
- The mandible bone is present at the base of the buccal cavity and is part of the skull.
- The axial skeleton in human beings consists of 80 bones.
- The front part of the skull in the facial region is formed by 14 skeletal elements.
- The atlas bone articulates with the occipital condyles.
- During muscle contraction, the shortening of the sarcomere is caused by the sliding of actin and myosin filaments.
- Repeated muscle activation leads to the accumulation of lactic acid in muscles.
- Myoglobin in muscles stores oxygen for later use.
- Muscle relaxation occurs when the 'Z' lines return to their original position, which is caused by the release of calcium ions.
This quiz covers the different types of muscle fibers, namely red and white fibers, and their characteristics. It explains the presence of mitochondria, myoglobin, and the reliance on aerobic or anaerobic processes in these muscle fibers.
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