Movement is a broader term that encompasses all types of motion, including cellular movements and the movement of body parts.
Types of Movement:
- Cellular Movement:
- Amoeboid movement: Seen in cells like white blood cells, it involves the formation of pseudopodia.
- Ciliary movement: Seen in cells like sperm and cilia in the respiratory tract.
- Muscular Movement:
- Skeletal muscles: Attached to bones, voluntary movement.
- Cardiac muscle: Involuntary, found in the heart.
- Smooth muscles: Involuntary, found in the walls of organs.
Skeletal System:
- Functions: Supports the body, protects organs, provides attachment points for muscles, produces blood cells, and stores minerals.
- Bones: Made of bone tissue, which contains calcium and phosphorus.
- Joints: Allow for movement between bones.
- Types of Joints: Immovable (fixed), slightly movable (cartilaginous), and freely movable (synovial).
Muscular System:
- Types of Muscle Fibers: Slow-twitch (red fibers, endurance) and fast-twitch (white fibers, power).
- Muscle Contraction: The sliding filament theory explains how muscles contract, involving the interaction of actin and myosin filaments.
- Muscle Disorders: Muscular dystrophy, myasthenia gravis.
Nervous System:
- Role: Controls movement by sending signals to muscles.
- Neuromuscular Junction: The junction between a nerve fiber and a muscle fiber.
- Neurotransmitters: Chemical messengers that transmit signals across the neuromuscular junction.
Coordination of Movement:
- Brain: Controls voluntary movements.
- Spinal Cord: Coordinates involuntary movements and reflexes.
- Cerebellum: Maintains balance and coordination.
Factors Affecting Locomotion:
- Skeletal System: The structure and strength of bones and joints.
- Muscular System: The size, strength, and endurance of muscles.
- Nervous System: The efficiency of nerve signals and coordination.
- Environmental Factors: Terrain, obstacles, and weather conditions.
Exercise
1. Draw the diagram of a sarcomere of skeletal muscle showing different regions
Ans :
2. Define sliding filament theory of muscle contraction.
Ans : Sliding Filament Theory is the most widely accepted explanation for how muscles contract. It proposes that muscle contraction occurs due to the sliding of thin (actin) filaments over thick (myosin) filaments within a sarcomere, the basic unit of muscle contraction.
3. Describe the important steps in muscle contraction.
Ans :
Muscle contraction is a complex process involving the interaction of several proteins and the release of calcium ions. Here are the main steps:
- Nerve Impulse: A nerve impulse travels down a motor neuron and reaches the neuromuscular junction, where it stimulates the release of acetylcholine (ACh).
- Acetylcholine Binding: ACh binds to receptors on the muscle fiber membrane, causing it to depolarize.
- Calcium Ion Release: Depolarization triggers the release of calcium ions from the sarcoplasmic reticulum (SR) into the sarcoplasm.
- Calcium Binding: Calcium ions bind to troponin, a protein associated with the actin filaments.
- Tropomyosin Movement: The binding of calcium ions causes tropomyosin, another protein associated with actin, to move, exposing the actin binding sites.
- Cross-Bridge Formation: Myosin heads bind to the exposed actin binding sites, forming cross-bridges.
- Power Stroke: The myosin heads exert a force and rotate, pulling the actin filaments towards the center of the sarcomere. This action shortens the sarcomere and causes the muscle to contract.
- Cross-Bridge Detachment: The myosin heads detach from the actin filaments and reattach to new binding sites, repeating the process.
- Muscle Relaxation: When the nerve impulse stops, calcium ions are reabsorbed into the SR, causing tropomyosin to cover the actin binding sites again. The cross-bridges detach, and the muscle relaxes.
4. 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.
Ans :
(a) True
(b) False
(c) True
(d) True
(e) True
5. Write the difference between :
(a) Actin and Myosin
(b) Red and White muscles
(c) Pectoral and Pelvic girdle
Ans :
(a) Actin and Myosin
| Feature | Actin | Myosin |
| Type of Filament | Thin filament | Thick filament |
| Role in Muscle Contraction | Sliding over myosin filaments | Binding to actin filaments and generating force |
| Structure | Composed of actin monomers | Composed of myosin heavy chains and myosin light chains |
| Location | Found in the I-band of a sarcomere | Found in the A-band of a sarcomere |
(b) Red and White muscles
| Feature | Red Muscle Fibers | White Muscle Fibers |
| Color | Red | White |
| Myoglobin Content | High | Low |
| Mitochondria | Abundant | Fewer |
| Contraction Type | Slow-twitch (endurance) | Fast-twitch (power) |
| Examples | Muscles used for endurance activities (e.g., marathon running) | Muscles used for explosive activities (e.g., sprinting) |
(c) Pectoral and Pelvic girdle
| Feature | Pectoral Girdle | Pelvic Girdle |
| Location | Upper chest | Lower back |
| Bones | Clavicle (collarbone) and scapula (shoulder blade) | Ilium, ischium, and pubis |
| Attachments | Attaches the upper limbs to the axial skeleton | Attaches the lower limbs to the axial skeleton |
| Function | Provides support for the upper limbs and allows for a wide range of movement | Provides support for the lower limbs and transmits weight to the legs |
6. 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
Ans :
(a) Smooth muscle – (iv) Involuntary
(b) Tropomyosin – (ii) Thin filament
(c) Red muscle – (i) Myoglobin
(d) Skull – (iii) Sutures
7. What are the different types of movements exhibited by the cells of human body?
Ans :
Human cells exhibit various types of movement, including:
- Amoeboid movement: This involves the formation of temporary extensions called pseudopodia, allowing cells to crawl and migrate. Examples include white blood cells and some cancer cells.
- Ciliary movement: Cilia are hair-like structures that beat rhythmically to propel cells or substances.
- Flagellar movement: Flagella are longer and more whip-like structures that also propel cells. Sperm cells are a prime example of cells with flagella.
- Brownian motion: This is a random movement of particles caused by the collision of molecules. It is seen in cells suspended in a fluid.
8.How do you distinguish between a skeletal muscle and a cardiac muscle?
Ans :
| Feature | Skeletal Muscle | Cardiac Muscle |
| Location | Attached to bones | Found only in the walls of the heart |
| Control | Voluntary (can be consciously controlled) | Involuntary (not under conscious control) |
| Structure | Striated (has a striped appearance) | Striated (has a striped appearance) |
| Cells | Multinucleated (has multiple nuclei) | Mononucleated (has a single nucleus) |
| Contraction | Can contract forcefully and rapidly | Contracts rhythmically and forcefully |
| Energy Source | Primarily aerobic respiration | Both aerobic and anaerobic respiration |
| Regeneration | Limited ability to regenerate | Cannot regenerate after injury |
9. 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
Ans :
(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: Sutures
(f) Between pubic bones in the pelvic girdle: Symphysis pubis
10. 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 ‘F’ actins and two other proteins namely __________ and __________.
(d) In a muscle fibre Ca++ is stored in __________
(e) __________ and __________ pairs of ribs are called floating ribs.
(f) The human cranium is made of __________ bones.
Ans :
(a) 7
(b) 14.
(c) troponin and tropomyosin.
(d) sarcoplasmic reticulum.
(e) 11 and 12
(f) 8
