PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Very short answer type questions

Question 1.
Give the name of the cells/tissues in human body which:
(i) exhibit amoeboid movement.
(ii) exhibit ciliary movement. [NCERT Exemplar]
Answer:
(i) Macrophages,
(ii) Ciliated, epithelium of trachea.

Question 2.
Which property of muscles is used effectively in muscular movement?
Answer:
Contractile property of muscles.

Question 3.
Give the name of the oxygen-carrying pigment present in skeletal muscle.
Answer:
Myoglobin or muscle hemoglobin.

Question 4.
Label the different components of actin filament in the diagram given below: [NCERT Exemplar]
Answer:

Question 5.
What causes muscle fatigue?
Answer:
Accumulation of lactic acid.

Question 6.
The three tiny bones present in middle ear are called ear ossicles. Write them in correct sequence beginning from eardrum. [NCERT Exemplar]
Answer:
Malleus, incus and stapes.

Question 7.
What is the difference between the matrix of bone and cartilage? [NCERT Exemplar]
Answer:
The matrix of bone is hard due to calcium salts, whereas, the cartilage has slightly pliable matrix due to chondroitin salts.

Question 8.
How many total bones are there in human body? Name the largest and strongest bone.
Answer:
Human body contains 206 bones. Femur is the largest and strongest bone of human body.

Question 9.
Give the name of the cavity in the girdle to which head of femur articulates.
Answer:
Acetabulum.

Question 10.
Give the name of the funny bone.
Answer:
Olecranon process on top of the ulna is called the funny bone.

Question 11.
Give the location of ball and socket joint in a human body. [NCERT Exemplar]
Answer:
Shoulder joint (between pectoral girdle and head of humerus).

Question 12.
What substance is responsible for lubricating the freely movable joint at the shoulder? ,
Answer:
Synovial fluid.

Short answer type questions

Question 1.
Explain anaerobic breakdown of glycogen in muscles and its effect.
Answer:
Anaerobic Breakdown of Glycogen: The reaction time of the fibres can vary in different muscles. Repeated activation of the muscles can lead to the accumulation of lactic acid due to anaerobic breakdown of glycogen in them, causing fatigue.

Question 2.
Describe the structure of the human skull.
Answer:

• The skull is composed of two sets of bones-cranial and facial, that totals to 22 bones.
• Cranial bones are 8 in number. They form the hard protective outer covering, cranium for the brain.
• The facial region is made up of 14 skeletal elements which form thefront part of the skull.
• A single U-shaped bone called hyoid is present at the base of the buccal cavity and it is also included in the skull.
• Each middle ear contains three tiny bones-Malleus, Incus and Stapes, collectively called Ear Ossicles.
• The skull region articulates with the superior region of the vertebral column with the help of two occipital condyles (dicondylic skull).

Question 3.
Explain the structure of the vertebral column of human.
Answer:
Vertebral Column: Our vertebral column is formed by 26 serially arranged units called vertebrae and is dorsally placed. It extends from the base of the skull and constitutes the main framework of the trunk. Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes.
First vertebra is the atlas and it articulates with the occipital condyles.

The vertebral column is differentiated into following regions starting from the skull:

1. cervical (7),
2. thoracic (12),
3. lumbar (5),
4. sacral (1-fused) and
5. coccygeal (1-fused) regions

The number of cervical vertebrae are seven in almost all mammals including human beings. The vertebral column protects the spinal cord, supports the head and serves as the point of attachment for the ribs and musculature of the back. Sternum is a flat bone on the ventral midline of thorax.

Question 4.
Describe the structure of the rib cage of human.
Answer:
Rib Cage: There are 12 pairs of ribs. Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum. It has two articulation surfaces on its dorsal end and is hence called bicephalic.
First seven pairs of ribs are called true ribs. Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage.

The 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage. These are called verte brochondral (false) ribs. Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are, therefore, called floating ribs. Thoracic vertebrae, ribs and sternum together form the rib cage.

Question 5.
Give a description of the appendicular skeleton in human.
Answer:
Appendicular Skeleton: The bones of the limbs alongwith their girdles constitute the appendicular skeleton. Each limb is made of 30 bones.

Bones of Limbs
Fore’ Limb	Hind Limb
Humerus,	Femur,
Radius,	Tibia,
Ulna	Fibula,
Carpals (8)	Tarsals (7)
Metacarpals (5)	Metatarsals (5)
Phalanges (14)	Phalanges (14)
	Patella

Question 6.
Write a short note on disorders of muscular and skeletal systems.
Answer:
Disorders of Muscular System

• Myasthenia gravis: It is an auto-immune disorder, affecting the neuromuscular junction leading to progressive weakening and paralysis of skeletal muscles.
• Muscular dystrophy: It is a genetic disorder resulting in progressive degeneration of skeletal muscles.
• Tetany: It refers to the continued state of contraction or wild contractions of muscles due to low Ca++ in body fluids.

Disorders of Skeletal System:

• Arthritis: Inflammation of joints.
• Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures. Decreased levels of estrogen is a common cause.
• Gout: Inflammation of joints due to accumulation of uric acid crystals.

Long answer type questions

Question 1.
Give answer for the following:
(i) Female pelvis is larger and has a broader front than male pelvis. Why?
(ii) Name the different curves of vertebral column.
(iii) What is a sesamoid bone? Name it.
(iv) Which bones have become modified to form ear ossicles?
Answer:
(i) Female pelvis is larger and has a broader front. This is an adaptation for childbirth.
(ii) Vertebral column forms four curves, i.e., cervical, thoracic, lumbar, and sacral located in the neck, thorax, abdomen, and pelvis respectively.
(iii) A bone embedded within a tendon is called a sesamoid bone, e.g., Patella which covers the knee ventrally.
(iv) Articular bone of lower jaw modifies to be malleus. Quadrate bone of upper jaw becomes incus and hyomandibular gets modified to become stapes.