Movement & Its Types | Biology Class 11 - NEET PDF Download

Body Movement

Movement is the change in the position of a body part with respect to the whole body. It is one of the significant features of all living beings. The blinking of the eyes, breathing, eating are all examples of movement. So we can say that every second some or the other part of our body exhibits some or other kind of movements.
The human body movements get polished as we grow in age. The movement starts from crawling and with the increase in age the person starts walking leading to the movement of the whole organism.
These movements are possible because of joints. Joints are points in our body where two or more parts of our skeleton are connected together. Different joints help our body carry out different activities and movements.

Types of Joints

• All bones in our body form a framework and provide shape to our body. This framework is called a skeleton.
• Our hand is made up of several small bones called Carpals.
• Chest bones and backbone together form the ribcage. We have 12 ribs on each side of our chest. Our backbone consists of 33 small, disk-like bones called vertebrae. Rib Cage protects the internal parts of our body and provides a definite structure.
• Bones in the shoulder are called shoulder bones and bones in the abdominal region are called pelvic bones.
• Skull is made up of many bones which are fused together. It protects our brain. Cartilages are also part of our skeletal system and joints of the body. Unlike bones, they are soft and flexible.
• Muscles are subjected to contraction and relaxation and work in pairs.

Locomotion

There are different types of locomotory movements in different organisms like paramecium have cilia which help in capturing food and also in locomotion. Hydra has tentacles for capturing prey and for locomotion. We use our limbs for different types of body movements. Locomotion is necessary for food, shelter etc.

Amoeboid Movements

Some of our internal tubular organs exhibit ciliary movement. Cilia are present in our trachea which helps in removing foreign particles, dust etc. The movement of ova in the female reproductive tract is also a type of ciliary movement.

Whenever we move, our limbs are involved. They are the muscular movements. In locomotion and other types of body movements in humans, the contractile property of the muscles is used.

Movements involve perfect coordination of the muscular, skeletal and neural system. There are a variety of muscles and joints involved in movements.

Cilia

Definition: Cilia are minute hair-like projections on the outer surface of a eukaryotic cell.

What are Cilia?
Cilia are small, slender, hair-like structures present on the surface of all mammalian cells. They are primitive in nature and could be single or many.
Cilia play a major role in locomotion. They are also involved in mechanoreception. The organisms that possess cilia are known as ciliates. They use their cilia for feeding and movement.
Cilia

Flagella

• Archaeal flagella are nonhomologous.
• Bacterial flagella are a coiled, thread-like structure, sharp bent, consisting of a rotary motor at its base and are composed of the protein flagellin.  A shaft exists between a hook and a basal body passing through the protein rings in the cell membrane. 
• Eukaryotic flagella are complicated cellular projections that pummel backwards and forward and are found in protist cells, gametes of plants, and animals. It is made up of a protein called tubulin.

The diagram of a sperm representing Flagella Structure at the posterior endFlagella Function
Flagella performs the following functions:

1. They help an organism in movement.
2. They act as sensory organs to detect temperature and pH changes.
3. Few eukaryotes use flagellum to increase reproduction rates.
4. Recent researches have proved that flagella are also used as a secretory organelle. For eg., in Chlamydomonas

Cilia and Flagella
Let us have a look at the important characteristics of cilia and flagella to understand how each one is different from the other.

A comparative diagram of Cilia and Flagella

Cilia

• Grouped into the category of protozoans, class Ciliata, in the Ciliated epithelium of the Metazoa and other classes.
• It is usually present on the outer body surface such as larva of certain Mollusca, Annelida, and Nemertines, thus helping in locomotion.
• It has similar structures and function as that of flagella, but cilium is shorter and movement is quite different.
• They are present in large numbers.
• Cilia exhibit beating motion.
• Cilia often cover the entire cell. They fuse into some protozoans to form cirri.

Flagella

• These are present in protozoans, choanocyte cells of Metazoa and in other classes- in plants, in gamete cells, and in algae.
• They are fairly long.
• They are fewer in number.
• It exhibits a coiled motion.
• They are usually found at one end of the cell.
• Flagella usually do not fuse.

Muscular System

What is the Muscular System?
The muscular system is an organ system, involved majorly in the movement of the body. There are nearly 700 muscles that are connected to the bones of the skeletal system, which roughly half make up the human’s body weight. Every muscle is a different organ made of blood vessels, skeletal muscle tissue, nerves, and tendons. Muscle tissues are found in the heart, blood vessels, and digestive system.
There are three kinds of muscle tissues, namely cardiac, visceral and skeletal:

1. Cardiac Muscle: This muscle is present only in the Heart and responsible for supplying blood all over the body. It is also an involuntary muscle since it cannot be controlled. When the brain signals adapt the rate of contraction, the cardiac muscle triggers by itself to contract. The natural pace of the heart is composed of cardiac muscle tissue and triggers other cardiac muscle cells to shrink.
   The cardiac muscle cells are straight which reveals that they seem to have dark and light stripes when seen under a microscope. The protein fibres arrangement within the cells is responsible for these dark and light stripes.
2. Visceral Muscle: These muscles are found in the organs like intestines, blood vessels, and stomach. It is the weakest of all muscle tissues and causes contraction of organs to pass substances through the organ. It is said to be an involuntary muscle because it cannot be controlled directly by the conscious mind, but controlled by the unconscious part of the brain. It is also known as a smooth muscle since it has a uniform and a smooth appearance when observed under the microscope.
3. Skeletal Muscle: It is the voluntary muscle tissue that can be controlled in conscious condition. All physical actions that a human performs (e.g. walking, writing) needs skeletal muscle. The skeletal muscle is responsible for moving the body parts that are connected to the bone.
   Skeletal muscles from many ancestor cells combine themselves together to produce a straight, long fibre. These skeletal muscles are strong just like cardiac muscles. The name is derived from the known fact that these are connected to the skeleton in one region at least.

Old NCERT Syllabus

Types of Body Movements
The body movements in humans are of the following types:

• Flexion
• Lateral Flexion
• Dorsiflexion
• Plantarflexion
• Extension
• Hyperextension
• Abduction
• Adduction
• Transverse Abduction
• Transverse Adduction
• Rotation Lateral Rotation
• Medial Rotation
• Supination
• Pronation Protraction
• Retraction
• Elevation
• Depression
• Reversion
• Eversion
• Opposition

Body Movement In Other Animals
1. Body Movement In Earthworm

• Earthworms do not have bones but are made up of several rings joined end to end.
• It is able to shorten and extend its body with the help of muscles.
• It is able to move through the soil as a result of repeated contractions and expansions 
• Excretes a slimy substance which aids its movement.
• It has many tiny bristles projecting out which are connected with muscles enabling them to get a good grip.

2. Body Movement In Snail
The outer skeleton is called the shell. It is not made up of bones and does not help in movement. The body consists of a head and a thick structure projecting out of the shell, which is the foot. It is made up of strong muscles. Their motion is wavy.
3. Body Movement In Cockroach

• They have three pairs of legs and can walk, climb, fly. The body is covered with a hard exoskeleton. The exoskeleton is made up of a number of plates joined together.
• They have 2 pairs of wings attached to the body. They have muscles too which helps them move when they fly.

4. Body Movement In Fish
The tail and head of a fish are smaller as compared to the middle portion. They are said to have a streamlined body which allows the fish to gain motion and swim.
5. Body Movement In Birds
The hollow bones and the strong muscular system helps the birds during flight. A bird flaps its wings while flying.

Types of Cilia

1. Motile Cilia
   These are found in large numbers on the surface of the cell. In humans, these are found in the respiratory epithelium of the respiratory tract. Here, they function by clearing the mucus and dust out of the lungs.
2. Non-motile Cilia
   Primary Cilia are non-motile cilia that were first discovered in 1898. These structures were long believed to be vestigial organelles. However, recent researches presented the biological roles of primary cilia that they function as a sensory cellular antenna that coordinates a large number of cellular signalling pathways. Apart from these, they also help in:
   (i) Proper urine flow by signalling the kidney cells.
   (ii) They act as mechanoreceptors or sensory receptors.
   (iii) The cilia function by permitting the transfer of important particles from one side of the light-sensitive cells to another in the retina.

Cilia Structure
Cilia are made up of microtubules coated by the plasma membrane. Each cilium comprises nine pairs of microtubules that form the outside ring and two central microtubules. This structure is called an axoneme. The nine outer pairs are made up of motor proteins called dynein. These are large and flexible that allows the cilia to move.
Cilia are attached to the cell at the basal body that is made up of microtubules arranged in nine triplets. They are very minute structures ranging from 0.25μm in diameter to 20μm in length.

Cilia Function
The important functions performed by cilia involve locomotion and sensory functions. They play a major role in cell cycle and replication and also in the development of humans and animals.
Multiple cilia move in a rhythmic motion that keeps the internal passageways free from mucus or any foreign agent.
A few non-motile cilia act as an antenna that receives sensory information for the cells and processes these signals from the surrounding fluids. E.g. the cilia present in the kidney bend forcefully as the urine passes.  This sends signals to the cells that the urine is flowing.
The non-motile cilia found in the photoreceptors of retina help in the transport of molecules from one end to the other.

Cilia Disorders

• Ciliopathies: It is a genetic disorder of the cilia structures – the basal bodies or of cilia function. Dysfunction or defects in primary and motile cilia are known to cause numerous distressing genetic disorders known as ciliopathies.
• Primary Ciliary Dyskinesia: It is an autosomal recessive disorder in which the cilia do not function normally. This condition prevents the clearing of mucus from the lungs, ears and sinuses.

Cilia Facts

• The organelle cilia are found in eukaryotic cells.
• They can be of two types – motile cilia and non-motile cilia.
• The non-motile cilia are known as primary cilia and act as sensory organelles.
• Cilia are structurally identical to flagella.
• Microorganisms such as paramecium contain cilia for locomotion.

Bacterial Flagella Structure

• Basal body
• Hook
• Filament

1. Basal Body: It is attached to the cell membrane and cytoplasmic membrane. It consists of rings surrounded by a pair of proteins called MotB. The rings include:
   (i) L-ring: Outer ring anchored in the lipopolysaccharide layer and found in gram +ve bacteria.
   (ii) P-ring: Anchored in the peptidoglycan layer.
   (iii) C-ring: Anchored in the cytoplasm.
   (iv) M-S ring: Anchored in the cytoplasmic membrane.
2. Hook: It is a broader area present at the base of the filament.
   Connects filament to the motor protein in the base.
   The hook length is greater in gram +ve bacteria.
3. Filament: Thin hair-like structure arising from the hook.

Types of Flagella
There are four different types of flagella:

1. Monotrichous: A single flagellum at one end or the other. These are known as polar flagellum and can rotate clockwise and anti-clockwise. The clockwise movement moves the organism forward while the anti-clockwise movement pulls it backwards.
2. Peritrichous: Several flagella attached all over the organism. These are not polar flagella because they are found all over the organism. These flagella rota anti-clockwise and form a bundle that moves the organism in one direction. If some of the flagella break and start rotating clockwise, the organism does not move in any direction and begins tumbling.
3. Lophotrichous: Several flagella at one end of the organism or the other. These are known as polar flagellum and can rotate clockwise and anti-clockwise. The clockwise movement moves the organism forward while the anti-clockwise movement pulls it backwards.
4. Amphitrichous: Single flagellum on both the ends of the organism. These are known as polar flagellum and can rotate clockwise and anti-clockwise. The clockwise movement moves the organism forward while the anti-clockwise movement pulls it backwards.