Body Movements
Questions and Answers.
1. What is the skeletal system?
Ans It is the framework of bones which protects and encloses the internal organs and give shape, strength and support to the body.
2. Which are the different types of bones in the skeletal system.
Ans there are 4 types of bones which are-
1. The Skull
2. The Spine
3. The Rib Cage
4. The Limbs (hind and fore limbs)
3. Explain the structure of the skull.
Ans The skull consist of 29 bones. It protects the brain and sensory organs.
Our of 29 bones -
8 are interlocked together and flat.
14 are facial bones enclosing the sensory organs.
6 are ear bones (3 in each ear)
1 in the neck (hyoid bone)
4. Explain the structure of Rib Cage.
Ans There are 12 pairs of ribs in a rib cage. 1-7 pairs are called true ribs. as they are connected to both backbone and the sternum. 8-10 pairs are called False ribs as they are connected to the backbone and 7th pair of rib. 11,12 are called floating ribs as they are only connected to the backbone and not the sternum. It protects the heart and the lungs.
5.Explain the structure of limbs (Forelimbs (arms) and Hind limbs (legs).
Ans Forelimbs- Forelimbs are joined to the shoulder girdle with the ball and socket joint. A Forelimb consist of Humerus, Radius, Ulna, carpals, Metacarpals and Phalanges.
4. Explain the structure of Rib Cage.
Ans There are 12 pairs of ribs in a rib cage. 1-7 pairs are called true ribs. as they are connected to both backbone and the sternum. 8-10 pairs are called False ribs as they are connected to the backbone and 7th pair of rib. 11,12 are called floating ribs as they are only connected to the backbone and not the sternum. It protects the heart and the lungs.
5.Explain the structure of limbs (Forelimbs (arms) and Hind limbs (legs).
Ans Forelimbs- Forelimbs are joined to the shoulder girdle with the ball and socket joint. A Forelimb consist of Humerus, Radius, Ulna, carpals, Metacarpals and Phalanges.
Hind limb
A hind limb consist of Tibia, Fibula, Patella, Tarsals, Metatarsals and Phalanges. Hind limb is joined to the pelvis with a ball and socket joint.
7. What are the function of the skeletal system.
Ans It supports the body and gives definite shape and strength to it.
2. It helps to protect delicate and vital organs like heart, lungs and brain, etc.
3. With the help of muscles it helps in the movement of body parts.
4. It is the storehouse of minerals and the place of formation of Red Blood Cells and White Blood Cells.
8. What are vertebrates and invertebrates?
Ans Vertebrates
Animals which possess a backbone are called vertebrates. eg Human beings, monkey, etc.
Invertebrates
Animals which don't possess a vertebral column are called In vertebrates. eg Earthworm, spider, starfish, etc.
Skeletal system- Axial skeletal system( Spine, Rib cage, Skull) , Appendicular skeletal system( Forelimb, Hind limb, hip and shoulder Girdles)
9. Explain the structure of girdles.
Ans Girdles give support to the bones of the limbs. The Girdle that support the bones of the arm is called shoulder girdle. The shoulder girdle consist of two pairs of bones- One pair of clavicles (collar bone) and one pair of scapulae ( shoulder blade). the girdle into which bones of legs are fitted is called hip girdle (pelvis).
There are 3 bones in the middle ear they are incus, stapes ( smallest bone in the body) and malleus.
Joints
A joint is a place where two or more bones meet. Bones are held together at a joint by a tissue called ligament. the ends of bones are covered with elastic, soft and flexible tissue called cartilage. It act as a shock absorber by preventing bones from rubbing against each other. A fluid called synovial fluid is also present between the joints to lubricate them.
Types of joint
On the bases of the movements joints are of 4 types-
Ball and socket joint
In this type of joint the ball like surface of one boll fits into a cup like hollow socket of another bone. this type of joint allow maximum movement. eg Joints present in the hip and shoulder girdle.
Pivot Joint
This joint the pointed part of one bone fits into the cavity of one bone that is the rounded surface of one bone fits into a ring form such that one bone is able to rotate over the other. Eg Neck joint
Hinge joint
This joint allows back and forth movement similar to the hinges of a door. Eg joints in the knee, finger, elbow and toes.
Gliding Joint
This kind of joint allows bones to glide over each other by providing a sliding movement in all direction. eg Joints in the wrist and spine
Dislocation
Sometimes because of careless movement or a bad fall. the bones at the joint slip out of their position this is called dislocation of bones a person who has a dislocated bone may have sprain or damaged ligament.
Muscles
Muscles are attached to bones by a fibre like tissue called tendons. Joints cannot bring about a movement with out he help of bones or muscle.One muscle pulls the bone away from the joint by contracting while the other muscle pulls it back by expanding. Biceps and triceps contract and expand respectively to move our forearm.
Movement in animals
Earthworm
Body of an earthworm is made up of number of segments. Its body is elongated, segmented and doesn’t have bones. It lives in moist soil, water and burrows. It respire through its moist skin. On the lower surface of its body hair like structure called bristle are present. These help it to get grip on the surface or ground when it moves.
10 How do earthworm help us?
Ans Earthworms live in the soil feeding on it. The undigested food is passed out as pallets while earthworms carry on their lives, like this they bring up the fertile soil from the bottom to the upper surface.
2. The earthworm make the soil soft and allow more air to get in. This helps the crops to grow healthier hence, we called them as ‘friends of farmers.’
3.The earthworm help in the decomposition of organic waste by converting it into useful fertilizes for the crop and plants.
Movement in earthworm
An earthworm can move in the soil by repeated contraction and expansion of muscles. Its body secretes a slimy substance that help in the movement. When an earthworm moves, the front end becomes long and thin and the rear end becomes short and thick due to the contraction and expansion of muscles.
Movement in bird
The features that help a bird to fly are-
1. Streamline body shape which reduces air resistance.
2. Hollow bones which makes them light weight.
3. They have wings made up of feathers.
4. They have very strong chest muscles and have large lungs.
Movement in a fish
They have streamline body shape.
Shape of the body reduces water resistance.
Fins play a major role in swimming.
The body of the fish is adapted for swimming in water in the following ways-
1. Streamline, spindle- shape body covered with scale. This body structure offers the least resistance and make their swim easier.
2. Skeleton is made up of thin bones with flexible backbone that help in swimming.
3. The swim bladder is filled with air to make the body buoyant making them to move up and down in water.
4. During swimming the front part of body curves on one side and tail on the opposite side than quickly it turns to its opposite side. This provide a jerk and pushes forward it repeats this for movement in forward direction. The body is balanced and kept steady by paired and unpaired fins.
Locomotion in snakes
The body of a snake is cylindrical, long and with scales. The scales on back are small. On ventral side the scales are big. The body has numerous muscles and vertebrae. The muscles interconnect the vertebrae, ribs and skin. They are also connected by tendons. Snakes slither on land to move by drawing on their belly. They form loops while moving. The forward push of the loops against the surface helps the snakes to move forward.
A hind limb consist of Tibia, Fibula, Patella, Tarsals, Metatarsals and Phalanges. Hind limb is joined to the pelvis with a ball and socket joint.
7. What are the function of the skeletal system.
Ans It supports the body and gives definite shape and strength to it.
2. It helps to protect delicate and vital organs like heart, lungs and brain, etc.
3. With the help of muscles it helps in the movement of body parts.
4. It is the storehouse of minerals and the place of formation of Red Blood Cells and White Blood Cells.
8. What are vertebrates and invertebrates?
Ans Vertebrates
Animals which possess a backbone are called vertebrates. eg Human beings, monkey, etc.
Invertebrates
Animals which don't possess a vertebral column are called In vertebrates. eg Earthworm, spider, starfish, etc.
Skeletal system- Axial skeletal system( Spine, Rib cage, Skull) , Appendicular skeletal system( Forelimb, Hind limb, hip and shoulder Girdles)
9. Explain the structure of girdles.
Ans Girdles give support to the bones of the limbs. The Girdle that support the bones of the arm is called shoulder girdle. The shoulder girdle consist of two pairs of bones- One pair of clavicles (collar bone) and one pair of scapulae ( shoulder blade). the girdle into which bones of legs are fitted is called hip girdle (pelvis).
There are 3 bones in the middle ear they are incus, stapes ( smallest bone in the body) and malleus.
Joints
A joint is a place where two or more bones meet. Bones are held together at a joint by a tissue called ligament. the ends of bones are covered with elastic, soft and flexible tissue called cartilage. It act as a shock absorber by preventing bones from rubbing against each other. A fluid called synovial fluid is also present between the joints to lubricate them.
Types of joint
On the bases of the movements joints are of 4 types-
Ball and socket joint
In this type of joint the ball like surface of one boll fits into a cup like hollow socket of another bone. this type of joint allow maximum movement. eg Joints present in the hip and shoulder girdle.
Pivot Joint
This joint the pointed part of one bone fits into the cavity of one bone that is the rounded surface of one bone fits into a ring form such that one bone is able to rotate over the other. Eg Neck joint
Hinge joint
This joint allows back and forth movement similar to the hinges of a door. Eg joints in the knee, finger, elbow and toes.
Gliding Joint
This kind of joint allows bones to glide over each other by providing a sliding movement in all direction. eg Joints in the wrist and spine
Dislocation
Sometimes because of careless movement or a bad fall. the bones at the joint slip out of their position this is called dislocation of bones a person who has a dislocated bone may have sprain or damaged ligament.
Muscles
Muscles are attached to bones by a fibre like tissue called tendons. Joints cannot bring about a movement with out he help of bones or muscle.One muscle pulls the bone away from the joint by contracting while the other muscle pulls it back by expanding. Biceps and triceps contract and expand respectively to move our forearm.
Movement in animals
Earthworm
Body of an earthworm is made up of number of segments. Its body is elongated, segmented and doesn’t have bones. It lives in moist soil, water and burrows. It respire through its moist skin. On the lower surface of its body hair like structure called bristle are present. These help it to get grip on the surface or ground when it moves.
10 How do earthworm help us?
Ans Earthworms live in the soil feeding on it. The undigested food is passed out as pallets while earthworms carry on their lives, like this they bring up the fertile soil from the bottom to the upper surface.
2. The earthworm make the soil soft and allow more air to get in. This helps the crops to grow healthier hence, we called them as ‘friends of farmers.’
3.The earthworm help in the decomposition of organic waste by converting it into useful fertilizes for the crop and plants.
Movement in earthworm
An earthworm can move in the soil by repeated contraction and expansion of muscles. Its body secretes a slimy substance that help in the movement. When an earthworm moves, the front end becomes long and thin and the rear end becomes short and thick due to the contraction and expansion of muscles.
Movement in bird
The features that help a bird to fly are-
1. Streamline body shape which reduces air resistance.
2. Hollow bones which makes them light weight.
3. They have wings made up of feathers.
4. They have very strong chest muscles and have large lungs.
Movement in a fish
They have streamline body shape.
Shape of the body reduces water resistance.
Fins play a major role in swimming.
The body of the fish is adapted for swimming in water in the following ways-
1. Streamline, spindle- shape body covered with scale. This body structure offers the least resistance and make their swim easier.
2. Skeleton is made up of thin bones with flexible backbone that help in swimming.
3. The swim bladder is filled with air to make the body buoyant making them to move up and down in water.
4. During swimming the front part of body curves on one side and tail on the opposite side than quickly it turns to its opposite side. This provide a jerk and pushes forward it repeats this for movement in forward direction. The body is balanced and kept steady by paired and unpaired fins.
Locomotion in snakes
The body of a snake is cylindrical, long and with scales. The scales on back are small. On ventral side the scales are big. The body has numerous muscles and vertebrae. The muscles interconnect the vertebrae, ribs and skin. They are also connected by tendons. Snakes slither on land to move by drawing on their belly. They form loops while moving. The forward push of the loops against the surface helps the snakes to move forward.
Movement in a snail
Its body is soft and
unsegmented and it has a shell on its body. They have a pair of eyes and a pair
of tentacles. It fells its foods with tentacles. They move slowly with the help
of its flat muscular foot which produce a mucus. The snail crawls smoothly on
the layer of mucus. The flat muscular foot is present under its belly when a
snail moves. It looks like it’s moving on its belly.
Movement in a cockroach
The body of a cockroach
is divided into head, thorax and abdomen. It has tree pairs of legs and two
pairs of wings. Wings are attached to the breast muscles. The legs help them to
crawl and climb. The wings help them to fly.
11. Fins play a major role in
swimming in fish. Explain.
Ans 1. The Dorsal,
pelvic and anal fins help the fish to balance its body in water and don’t allow
it to topple.
2. The
pectoral fins allow it to stop suddenly or to move slowly in water. These fins
are like oars to push the water.
3. The tail
of a fish acts like a rudder of a boat and helps it to change the direction of
movement.
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