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Locomotion and Muscle Physiology
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Locomotion and Muscle Physiology
Locomotion and Muscle Physiology
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1
Question
What distinguishes locomotion from other forms of movement in animals?
Page 1
Answer
Locomotion changes the place or location of the animal. Other movements do not change position.
2
Question
How do locomotory structures relate to structures used in other movements?
Page 1
Answer
Locomotory structures are not different from those affecting other movements. Cilia in Paramoecium aid food movement and locomotion.
3
Question
Why is locomotion generally performed by animals?
Page 1
Answer
For search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions, or escape from enemies/predators.
4
Question
What are the three main types of movements exhibited by cells of the human body?
Page 1
Answer
Amoeboid, ciliary, and muscular movements.
5
Question
What cells exhibit amoeboid movement in the human body?
Page 2
Answer
Specialised cells like macrophages and leucocytes in blood.
6
Question
How is amoeboid movement effected in human cells?
Page 2
Answer
By pseudopodia formed by streaming of protoplasm. Cytoskeletal elements like microfilaments are involved.
7
Question
Where does ciliary movement occur in the human body?
Page 2
Answer
In most internal tubular organs lined by ciliated epithelium.
8
Question
What functions do cilia serve in the trachea and female reproductive tract?
Page 2
Answer
Trachea: remove dust particles and foreign substances with air. Reproductive tract: facilitate passage of ova.
9
Question
What coordinated systems are required for locomotion in multicellular organisms?
Page 2
Answer
Muscular, skeletal, and neural systems.
10
Question
What is muscle tissue's origin and contribution to body weight?
Page 2
Answer
Mesodermal origin. About 40-50 per cent of human adult body weight.
11
Question
What special properties do muscles possess?
Page 2
Answer
Excitability, contractility, extensibility, and elasticity.
12
Question
How are muscles classified based on location?
Page 2
Answer
Skeletal, visceral, and cardiac muscles.
13
Question
What are characteristics of skeletal muscles?
Page 2
Answer
Closely associated with skeletal components. Striped appearance (striated). Voluntary control by nervous system. Involved in locomotory actions and body posture changes.
14
Question
Where are visceral muscles located and what are their properties?
Page 2
Answer
Inner walls of hollow visceral organs like alimentary canal and reproductive tract. Nonstriated (smooth). Involuntary control.
15
Question
How do cardiac muscles differ from skeletal and visceral muscles?
Page 3
Answer
Muscles of heart. Striated appearance. Involuntary nature as nervous system does not control directly. Branched pattern.
16
Question
What encloses the sarcoplasm in a muscle fiber?
Page 3
Answer
Plasma membrane called sarcolemma.
17
Question
Why is a muscle fiber considered a syncytium?
Page 3
Answer
Sarcoplasm contains many nuclei.
18
Question
What is the function of sarcoplasmic reticulum in muscle fibers?
Page 3
Answer
Store house of calcium ions.
19
Question
What are the parallelly arranged filaments in sarcoplasm called?
Page 3
Answer
Myofilaments or myofibrils.
20
Question
What causes the striated appearance of myofibrils?
Page 3
Answer
Alternate dark and light bands due to distribution of actin and myosin.
21
Question
What do light bands in myofibrils contain and what are they called?
Page 3
Answer
Actin. Called I-band or isotropic band.
22
Question
What do dark bands in myofibrils contain and what are they called?
Page 3
Answer
Myosin. Called A-band or anisotropic band.
23
Question
What is the functional unit of contraction in a myofibril?
Page 4
Answer
Portion between two successive Z-lines called sarcomere.
24
Question
In resting state sarcomere, what is the H-zone?
Page 4
Answer
Central part of thick filament not overlapped by thin filaments.
25
Question
What bisects the I-band in sarcomere?
Page 4
Answer
Elastic fibre called Z-line.
26
Question
What holds thick filaments together in the middle of A-band?
Page 4
Answer
Thin fibrous membrane called M-line.
27
Question
How do thin and thick filaments differ in structure?
Page 4
Answer
Both rod-like, parallel to myofibril axis. Actin filaments thinner than myosin filaments.
28
Question
What is each actin filament made of?
Page 5
Answer
Two F (filamentous) actins helically wound. F-actin polymer of G (globular) actins.
29
Question
What proteins run close to F-actins in thin filament?
Page 5
Answer
Two filaments of tropomyosin. Troponin distributed at regular intervals on tropomyosin.
30
Question
What constitutes a thick myosin filament?
Page 5
Answer
Polymerised protein from many monomeric meromyosins.