Locomotion and Movement - Class 11 Biology - Chapter 17 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Locomotion and Movement | NCERT | Biology | Class 11
The rhythmic muscular contraction that pushes food from the esophagus into the stomach is called:
A. peristalsis
B. ingestion
C. digestion
The correct answer is A. peristalsis.
Peristalsis refers to the rhythmic contractions of muscles in the esophagus that facilitate the unidirectional movement of food into the stomach.
Choose the correct option: Statement 1: Locomotion is the movement of an individual from one place to another place. Statement 2: All locomotions are movements, but not all movements are locomotion.
A) Both statements are True. B) Both statements are False. C) Only Statement 1 is True. D) Only Statement 2 is True.
The correct answer is A) Both statements are True.
Statement 1 describes locomotion as the movement of an individual from one place to another. This definition correctly captures the essence of locomotion, which specifically involves spatial displacement from one location to another. Therefore, Statement 1 is True.
Statement 2 claims that all locomotions are movements, but not all movements are locomotion. This statement is also accurate because while locomotion is a specific type of movement involving displacement, other forms of movement (like the contraction of muscles, bending of limbs, or even the beating of the heart) do not necessarily result in a change of position from one place to another. Thus, Statement 2 is True as well.
Each statement individually corrects and supports the claim made in option A, which states that both statements are true.
"I am continuously shaking both of my legs in an oscillating manner, back and forth, while sitting on a chair. Am I said to be in motion or not, and why?"
Motion is a relative concept; it depends on the frame of reference used to observe it. In the scenario described:
With respect to your entire body sitting on the chair (considering the chair and the rest of your body as a reference), you are at rest, as there is no change in position of your body relative to the chair.
However, with respect to your legs, they are in motion because they are oscillating back and forth. Thus, relative to other parts of your body (like your torso or the chair), your legs are moving.
Hence, you personally are mostly at rest (your body excluding the legs), but your legs are clearly in motion due to their oscillatory movement.
How many types of muscle tissue are found?
A. Striated and unstriated
B. Striated and cardiac
C. Cardiac and unstriated
D. Striated, unstriated, and cardiac.
There are three main types of muscle tissues identified in the human body:
Skeletal muscles - These muscles are also known as striated muscles because of their appearance under a microscope.
Cardiac muscle - This type is specific to the heart and is also striated, but it is specialized and structured differently from skeletal muscle.
Smooth muscles - These are found in the walls of hollow organs like intestines and blood vessels and are known as non-striated or unstriated muscles since they do not show the same striations as skeletal or cardiac muscles.
Given this classification, the correct answer to how many types of muscle tissues are found is:
D. Striated, unstriated, and cardiac.
Each type plays a crucial role in the body's function, demonstrating distinct structural and functional characteristics. Thus, option D correctly encompasses all three tissue types found in the human body.
Which of the following muscle types contains peripherally located, multiple nuclei in its cells?
A. skeletal
B. cardiac
C. smooth
D. all of the above
The correct answer is A. skeletal.
Skeletal muscle cells are characterized by having multiple nuclei that are located peripherally within each cell. This is a distinctive feature compared to other muscle cell types.
Which part of the bird helps it to walk on the ground?
Forelimb
Hindlimb
Wings
Muscles
The correct option is B: Hindlimb
The forelimbs of birds are modified into wings. Therefore, the primary mode of locomotion for most bird species is flight, which they achieve with the help of their wings. However, another mode of locomotion for birds is walking on the ground, which is facilitated by their hindlimbs.
The bones in the hindlimbs are specifically adapted to enable a bird to walk and perch effectively.
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Draw the diagram of a sarcomere of skeletal muscle showing different regions.
Here is a diagrammatic representation of a sarcomere in a skeletal muscle, highlighting the different regions:
Key regions to note:
I-band: Contains only actin (thin) filaments.
A-band: Contains both actin and myosin (thick) filaments.
H-zone: Central part of A-band with only myosin (thick) filaments.
Z-line: Defines the boundaries of a sarcomere; actin filaments are anchored here.
M-line: Central line in the H-zone which holds the myosin filaments together.
These regions together form the repeating units of the myofibrils, contributing to the striated appearance of skeletal muscles.
Define sliding filament theory of muscle contraction.
The sliding filament theory of muscle contraction explains that the contraction of a muscle fiber occurs by the sliding of thin filaments (actin) over thick filaments (myosin). Here are the key steps:
Initiation: Muscle contraction begins with a signal sent by the central nervous system (CNS) via a motor neuron.
Neuromuscular Junction: The signal reaches the neuromuscular junction, releasing the neurotransmitter acetylcholine, which generates an action potential in the muscle fiber.
Calcium Release: The action potential causes the release of calcium ions (Ca²⁺) from the sarcoplasmic reticulum into the sarcoplasm.
Binding: Calcium ions bind to troponin, causing a change that exposes the active binding sites for myosin on the actin filaments.
Cross-Bridge Formation: Myosin heads bind to the exposed sites on actin, forming cross-bridges.
Sliding: Utilizing ATP, myosin heads pivot and pull the actin filaments toward the center of the ‘A’ band, resulting in the shortening of the sarcomere.
Relaxation: Calcium ions are pumped back into the sarcoplasmic reticulum, and the cross-bridges detach, leading to muscle relaxation.
Describe the important steps in muscle contraction.
The important steps in muscle contraction can be summarized as follows:
Initiation by Neural Signal: Muscle contraction is initiated by a signal sent by the central nervous system (CNS) via a motor neuron.
Neuromuscular Junction: The signal reaches the neuromuscular junction or motor-end plate, releasing a neurotransmitter (Acetyl choline), which generates an action potential in the sarcolemma of the muscle fibre.
Release of Calcium Ions: The action potential spreads through the muscle fibre, causing the release of calcium ions ((Ca^{++})) into the sarcoplasm.
Binding of Calcium to Troponin: The increase in (Ca^{++}) levels leads to the binding of calcium with a subunit of troponin on actin filaments. This removes the masking of active sites for myosin on the actin filaments.
Cross Bridge Formation: Utilizing energy from ATP hydrolysis, the myosin head binds to the exposed active sites on actin to form a cross bridge.
Sliding Filaments: The cross bridges pull the attached actin filaments towards the centre of the 'A' band. The 'Z' lines attached to these actins are also pulled inwards, causing the shortening of the sarcomere, i.e., contraction. Notably, the 'I' bands get reduced, whereas the 'A' bands retain their length.
Release and Reset: Myosin releases ADP and (P_i ) and goes back to its relaxed state. A new ATP binds, breaking the cross-bridge. The cycle of cross bridge formation and breakage is repeated for further sliding.
Relaxation: The process continues until (Ca^{++}) ions are pumped back to the sarcoplasmic reticulum, resulting in the re-masking of the actin filaments. This causes the return of the 'Z' lines back to their original position, resulting in relaxation.
The overall process is driven by the sliding filament theory, which explains muscle contraction as the sliding of thin filaments (actin) over thick filaments (myosin).
Write true or false. If false change the statement so that it is true.
(a) Actin is present in thin filament
(b) H-zone of striated muscle fibre represents both thick and thin filaments.
(c) Human skeleton has 206 bones.
(d) There are 11 pairs of ribs in man.
(e) Sternum is present on the ventral side of the body.
(a) True
Actin is present in thin filament.
(b) False
The H-zone of striated muscle fibre represents only thick filaments.
(c) True
Human skeleton has 206 bones.
(d) False
There are 12 pairs of ribs in man.
(e) True
Sternum is present on the ventral side of the body.
Write the difference between :
(a) Actin and Myosin
(b) Red and White muscles
(c) Pectoral and Pelvic girdle
(a) Actin and Myosin
Feature | Actin | Myosin |
---|---|---|
Appearance | Forms thin filaments | Forms thick filaments |
Band Association | Present in light bands (I-bands) | Present in dark bands (A-bands) |
Binding Sites | Has binding sites for myosin | Has ATP binding sites and active sites for actin |
Role | Involved in muscle contraction | Functions as a motor protein for muscle contraction |
(b) Red and White Muscles
Feature | Red Muscles | White Muscles |
---|---|---|
Color | Red due to high myoglobin content | White due to low myoglobin content |
Function | Aerobic; sustained activities like walking | Anaerobic; bursts of powerful movements |
Mitochondria | High number of mitochondria | Fewer mitochondria |
Fatigue | Resist fatigue; slow-twitch | Fatigue quickly; fast-twitch |
(c) Pectoral and Pelvic Girdle
Feature | Pectoral Girdle | Pelvic Girdle |
---|---|---|
Location | Located in the upper part of the thorax | Located in the lower part of the trunk |
Bones Involved | Comprises clavicle (collar bone) and scapula (shoulder blade) | Made up of two coxal bones (ilium, ischium, and pubis) |
Function | Supports the upper limbs and facilitates their movement | Supports the lower limbs and bears the weight of the body |
Articulation | Articulates with the head of the humerus forming the shoulder joint | Articulates with the head of the femur forming the hip joint |
Match Column I with Column II :
Column I | Column II |
---|---|
(a) Smooth muscle | (i) Myoglobin |
(b) Tropomyosin | (ii) Thin filament |
(c) Red muscle | (iii) Sutures |
(d) Skull | (iv) Involuntary |
Column I | Column II |
---|---|
(a) Smooth muscle | (iv) Involuntary |
(b) Tropomyosin | (ii) Thin filament |
(c) Red muscle | (i) Myoglobin |
(d) Skull | (iii) Sutures |
Explanation:
Smooth muscle is involuntary.
Tropomyosin is part of the thin filament in muscle fibers.
Red muscle contains myoglobin, which makes it red.
The skull bones are joined by sutures.
What are the different types of movements exhibited by the cells of human body?
The cells of the human body exhibit three main types of movements:
Amoeboid Movement:
Seen in specialized cells like macrophages and leucocytes.
Effected by pseudopodia formed through the streaming of protoplasm.
Involves cytoskeletal elements like microfilaments.
Ciliary Movement:
Occurs in most internal tubular organs lined by ciliated epithelium.
Coordinated movements of cilia help in functions like removing dust particles in the trachea and facilitating the passage of ova through the female reproductive tract.
Muscular Movement:
Required for movements of limbs, jaws, tongue, etc.
Utilizes the contractile property of muscles for locomotion and various other movements.
Requires a coordinated activity of the muscular, skeletal, and neural systems.
Each type of movement is crucial for different physiological processes in the human body.
How do you distinguish between a skeletal muscle and a cardiac muscle?
To distinguish between skeletal muscle and cardiac muscle, consider the following points:
Location:
Skeletal Muscle: Found attached to skeletal components of the body.
Cardiac Muscle: Found in the heart.
Appearance under Microscope:
Skeletal Muscle: Has a striped (striated) appearance.
Cardiac Muscle: Also has a striated appearance, but the cells are branched.
Control:
Skeletal Muscle: Voluntary, controlled by the nervous system.
Cardiac Muscle: Involuntary, not directly controlled by the nervous system.
Function:
Skeletal Muscle: Primarily involved in locomotory actions and changes in body postures.
Cardiac Muscle: Primarily involved in pumping blood throughout the body.
Cell Structure:
Skeletal Muscle: Cells are multi-nucleated and have long, cylindrical shapes.
Cardiac Muscle: Cells are connected by intercalated discs, which help synchronize heart contractions.
By considering these characteristics, you can accurately distinguish between the two types of muscle.
Name the type of joint between the following:-
(a) atlas/axis
(b) carpal/metacarpal of thumb
(c) between phalanges
(d) femur/acetabulum
(e) between cranial bones
(f) between pubic bones in the pelvic girdle
(a) atlas/axis: Pivot joint
(b) carpal/metacarpal of thumb: Saddle joint
(c) between phalanges: Hinge joint
(d) femur/acetabulum: Ball and socket joint
(e) between cranial bones: Fibrous joint
(f) between pubic bones in the pelvic girdle: Cartilaginous joint
Fill in the blank spaces:
(a) All mammals (except a few) have ____________ cervical vertebra.
(b) The number of phalanges in each limb of human is ____________
(c) Thin filament of myofibril contains 2 ' $\mathrm{F}$ ' actins and two other proteins namely ____________ and . ____________
(d) In a muscle fibre $\mathrm{Ca}^{++}$is stored in ____________
(e) ____________ and ____________ pairs of ribs are called floating ribs.
(f) The human cranium is made of ____________ bones.
(a) All mammals (except a few) have seven cervical vertebra. (b) The number of phalanges in each limb of human is 14. (c) Thin filament of myofibril contains 2 ' F ' actins and two other proteins namely tropomyosin and troponin. (d) In a muscle fibre Ca++ is stored in sarcoplasmic reticulum. (e) 11th and 12th pairs of ribs are called floating ribs. (f) The human cranium is made of 22 bones.
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Comprehensive Notes on Locomotion and Movement for Class 11 Students
Introduction to Locomotion and Movement
Understanding Movement and Locomotion
Movement is a fundamental feature of all living organisms. It can be observed in plants and animals in various forms. For instance, the streaming of protoplasm in Amoeba or the movement of tentacles in some aquatic organisms. Voluntary movements like walking, running, flying, and swimming are termed as locomotion. All locomotions are movements, but not all movements result in locomotion.
Types of Movement in Organisms
Amoeboid Movement
Amoeboid movement is exhibited by certain cells in our body like macrophages and leucocytes. It involves the formation of pseudopodia, facilitated by the streaming of protoplasm.
Ciliary Movement
Ciliary movement is observed in our internal tubular organs lined by ciliated epithelium. For example, cilia in the trachea move dust particles out of the respiratory tract, and the passage of ova through the female reproductive tract is aided by ciliary action.
Muscular Movement
Muscular movement is crucial for the movement of limbs, jaws, and other parts of the body. Muscle contraction enables these movements and involves complex coordination between muscular, skeletal, and neural systems.
The Muscle System
Types of Muscles
-
Skeletal Muscles:
- Striated in appearance.
- Under voluntary control.
- Assist in body postures and locomotion.
-
Visceral Muscles:
- Smooth and unstriated.
- Involuntary control.
- Found in inner walls of hollow organs.
-
Cardiac Muscles:
- Striated and branched.
- Involuntary.
- Make up the heart muscle.
Structure of Skeletal Muscle
Each organised skeletal muscle is composed of muscle bundles or fascicles. Each bundle consists of muscle fibres, which are lined by the sarcolemma and contain sarcoplasm. Muscle fibres are syncytial, containing multiple nuclei.
Mechanism of Muscle Contraction
Structure of Contractile Proteins
Actin filaments (thin) and Myosin filaments (thick) are the primary proteins involved in muscle contraction. Troponin and tropomyosin are other essential proteins that regulate the binding of these filaments.
Sliding Filament Theory
Muscle contraction is explained by the sliding filament theory. This theory states that the actin filaments slide over the myosin filaments during contraction, facilitated by ATP and calcium ions.
graph TD;
CNS -->|Signal| Motor_Neuron;
Motor_Neuron -->|Neurotransmitter Release| Muscle_Fiber;
Muscle_Fiber -->|Calcium Release| Actin_Myosin_Binding;
Actin_Myosin_Binding --> Contraction;
Muscle Fatigue
Repeated activities can lead to muscle fatigue, caused by the accumulation of lactic acid due to anaerobic respiration.
Skeletal System
The skeletal system consists of bones and cartilages, crucial for body movement and support. It is divided into two main parts:
Components of the Skeletal System
- Axial Skeleton: Includes the skull, vertebral column, ribs, and sternum.
- Appendicular Skeleton: Comprises limb bones and girdles.
Role of Bones and Cartilages
Bones provide structure and protection, and allow for movement when connected with muscles via tendons. Cartilages, though pliable, support and enable flexibility in certain parts of the skeleton.
Joints and Their Types
Joints are connections between bones allowing for various types of movement:
Classification of Joints
- Fibrous Joints: Immovable, found in the skull.
- Cartilaginous Joints: Slightly movable, such as the joints between vertebrae.
- Synovial Joints: Highly movable and include different types like ball and socket, hinge, pivot, and saddle joints.
Disorders of the Muscular and Skeletal Systems
Common Disorders
- Myasthenia Gravis: Autoimmune disorder affecting neuromuscular junctions.
- Muscular Dystrophy: Genetic disorder leading to degeneration of skeletal muscles.
- Tetany: Muscle spasms caused by low calcium.
- Arthritis: Inflammation of joints.
- Osteoporosis: Decreased bone mass, increasing fracture risk.
- Gout: Joint inflammation due to uric acid crystals.
Conclusion
Understanding locomotion and movement involves exploring various types of muscle and skeletal interactions. This knowledge is fundamental in comprehending how living organisms move, adapt, and function effectively. Such insights are crucial for Class 11 students in their biology curriculum, providing them with a comprehensive perspective on the biomechanics of movement.
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