Human body cells display three types of movement namely, Amoeboid, Ciliary, and Muscular.

Amoeboid movement is the most ordinary mode of locomotion in eukaryotic (membrane-bound nuclei) cells. It is a crawling-like type of movement accomplished by protuberance of the cytoplasm of the cell that requires the evolution of pseudopodia (false-feet) and posterior uropods. This type of movement has been linked to changes in the action potential.

Ciliary movement happens in most of our intramural tube-shaped organs which are bordered by endothelium. The coordinated movements of the centrosome in the esophagus help us in removing dust particles and some of the foreign substances inhaled along with the atmospheric air.

Muscles move body parts by shrinking and then relaxing. Muscles can tug bones, but they can't push them back to their initial position. Therefore, they work in couples of flexors and extensors.

Muscle is a specialized tissue of mesodermal origin. About 40-50 percent of the body weight of a human adult is put up by muscles. They have special properties like volatility, contractility, expansibility, and stretchiness. Muscles have been classified using different standards, namely placements, appearance, and nature of synchronization of their activities. There are three types of muscles, based on their placements, they are: (i) Skeletal (ii) Visceral, and (iii) Cardiac.

Skeletal muscle, also known as voluntary muscle, is the most ordinary of the three types of muscle in the body. Skeletal muscles are attached to bones by tissues, and they produce all types of movements. They are in skeletal components of the body such as Ribs, bones, hands, legs. It has a Striped, Striated appearance. Responsible for body posture and locomotion action.

Visceral, also known as smooth muscle, is found inside organs such as the stomach and intestines, as well as in the blood vessels. However, the visceral muscle is controlled by the unconscious part of the brain; it is known as involuntary muscle, as it cannot be controlled by the conscious mind. The appearance of these muscles is not-striped, non-striated, spindle shape. It is not under the voluntary control of the nervous system. These muscles are accountable for the transportation of food through the intestines and gametes through the genital tract.

The cardiac muscle also known as the heart muscle or myocardium is an involuntary, striated muscle that composes the main tissue of the wall of the heart. It has a striated and branched appearance. It is not under the voluntary control of the nervous system. Responsible for the regulation of cardiac activities.

Flagella movement helps in:

• Swimming of Spermatozoa
• Maintenance of water current
• Locomotion of protozoa’s ex- Euglena

Characteristics of muscle:

• Origin- Mesodermal
• Constituent- 40-50% of bodyweight (human adult)
• Properties- Excitability, Contractility, Extensibility, Elasticity

Muscle fibre contains:

1. Sarcolemma- It is a plasma membrane lining muscle fibre. For example- encloses Sarcoplasm

2. Sarcoplasm- It has many nuclei, therefore; muscle fibre is syncytium in nature.

3. Sarcoplasmic reticulum- Endoplasmic reticulum of muscle fibre. The storehouse of calcium ions is the example for Sarcoplasmic reticulum.

Muscle fibre features:

1. Myofibrils- It is parallelly arranged in the sarcoplasm. It is also known as Myofilaments. It has an appearance of Striated. It constitutes alternate dark and light bands called myosin and actin respectively.

Structure of contractile protein:

	Actin	Myosin
Colour	Light band	Dark band
Other names	I-band or isotropic bands	A-band or anisotropic band
nature	Thin	Thicker than Actin
Attached with	Firmly attached with ‘Z’ line	Firmly attached with ‘M’ line

Skeletal systems have a significant role in the movement of the body. Human body is made up of 206 bones and a few cartilages. It is assembled into two principal divisions – the axial and the appendicular skeleton. The axial skeleton consists of 80 bones which include three subcategories such as skull, Ribs, and vertebral. Skull has 22 bones, including facial bones which consist of 14 bones. The ribs are a set of twelve paired bones that form the shielding cage of the thorax. They coherent with the vertebral column (spinal column) backward and terminate antecedent as cartilage.

The spine has 33 stacked vertebrae or small bones that form the spinal canal. The spinal canal is a tunnel that chambers the spinal cord and nerves, safeguarding them from injury. Most vertebrae allow movement for a range of motion. The lowest vertebrae (sacrum and coccyx) are fused and don't move.

• Appendicular bones (Bones of limb and girdle): It includes hand and leg bones which include 30 bones each. Hand bones are Lunate.
• Triquetrum.
• Pisiform.
• Capitate.
• Trapezium.
• Trapezoid.
• Hamate.
• Scaphoid.

Leg bones are

• Femur – the bone in the thigh. 
• Patella – the kneecap. 
• Tibia – the shin bone, the larger of the two-leg bones found below the knee cap. 
• Fibula - smallest bone in leg bone, located below the knee cap.

Pectoral bones or the pelvic girdle consist of two bones: the sacrum and the coccyx. The pelvic girdle is formed when hip bones are put together, each made up of ilium, ischium, and pubis. The pectoral girdle is part of the appendicular skeleton which is for the upper limbs. In our human body, the pectoral girdle consists of the scapula and the clavicle.

A joint is a point where two bones connect, it is also a point where bones connect to move body parts.

• Function - helps in locomotion and movement.
• Action – It acts as a fulcrum in movement.
• Classification of joints:

1. Fibrous joint- Present in flat skull bones to form the cranium

    Allows no movement and locomotion

2. Cartilaginous joints- Present in adjacent vertebrae in the vertebral column.

    Allows limited movement

3. Synovial joints- Present between fluid-filled synovial cavities. It allows considerable movement and locomotion

• Myasthenia gravis: Autoimmune disorder influencing neuromuscular junction leading to tiredness, weakening, and immobility of skeletal muscle.
• Muscular dystrophy: Continuous degradation of skeletal muscle mostly due to a genetic disorder.
• Tetany: Rapid contractions in muscle due to low Ca++ in body fluid.
• Arthritis: Swelling of joints.
• Osteoporosis: Age-related disorder distinguished by decreased bone mass and increased chances of fractures. Reduced levels of estrogen are a common cause.
• Gout: Swelling of joints due to accumulation of uric acid crystals.

Q1. What topics are covered in the Chapter 20 locomotion and movement Class 11 Biology NCERT Solutions? 

Ans.

• Different types of movement.
• Muscle.
• Skeleton System.
• Joints.
• Disorders in the Skeleton and Muscular System.

Q2. Explain the Different Types of Movement Exhibited By the Cells of the Human Body.

Ans.

• Muscular movement- It is exhibited by the muscle cells/tissue found inside of the digestive organs, heart, and blood vessels. It is caused by the shrinking of the myofibrils or sarcostyle of the muscle cell.
• Amoeboid movement- It is revealed by the leukocytes or corpuscle of the blood.

Q3. Differences Between Red and White Muscle Fibre.

Ans.

Red Muscle Fibers	White Muscle Fibers
Definition
Red muscles are a kind of muscle fibre which are thick/opaque/heavy with capillaries and are rich in myoglobin and mitochondria.	White muscles are also a kind of muscle fibre, but contain lower numbers of myoglobin and mitochondria.
Mitochondria
More in number (dense)	less in number (sparse)
Sarcoplasmic Reticulum (SR)
Lesser amount of Sarcoplasmic Reticulum (SR) than white muscle.	More number of Sarcoplasmic Reticulum (SR) than red muscle.
Fatigue rate
It can carry out aerobic oxidation without collecting much lactic acid. Hence, it can contract for a longer period of time.	It carries out anaerobic oxidation and accumulates lactic acid much faster than red muscles. Hence, it exhausts after short bursts of contraction.
Contraction rate
Contraction rate is slower	Contraction rate is faster
Examples
Extensor muscles in human body	Eyeball muscle