Class 11 Anthropology Chapter 2 Human Skeleton

Class 11 Anthropology Chapter 2 Human Skeleton As Per New Syllabus. Class 11 Question Answer to each chapter is provided in the list so that you can easily browse throughout different chapters SCERT Class 11 Anthropology Chapter 2 Human Skeleton and select needs one.

Class 11 Anthropology Chapter 2 Human Skeleton

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Human Skeleton

Chapter – 2

EXERCISES

1. How many bones constitute the human skeleton?

Ans: There are 206 bones constitute the human skeleton.

2. Name the bone where foramen magnum is present?

Ans: The bone where foramen magnum is present in the occipital bone.

3. How many bones are there in the human skull?

Ans: There are 22 bones in the human skull.

4. What is suture? Name the bones which are joined by coronal suture.

Ans: Suture is a type of fibrous joint or synarthrosis that only occurs in the skull.

The bone which are joined by coronal suture is the parietal bone.

5. Name the longest and strongest bone of the human skeleton?

Ans: The longest and strongest bone of the human skeleton is femur.

6. Name the bone where auditory meatus is present?

Ans: The bone where auditory meatus is present in the temporal bone.

7. In which bone linea aspera is present?

Ans: Linea aspera is present in the femur.

8. How many bones constitute the vertebral column? What is the shape of the vertebral column?

Ans: There are 33 numbers of bone constitute the vertebral column.

‘S’ is the shape of the vertebral column.

9. Name the parts of a tooth?

Ans: The parts of a tooth are: crown, neck and root.

10. Name the first and second vertebrae of the vertebral column?

Ans: The first vertebrae of the vertebral column is the altas and the second vertebrae of the vertebral column is the axis.

11. How many parietal bones are there in the cranium? Name the bones that are joined by the sagittal suture?

Ans: There are two parietal bones in the cranium.

The bones that are joined by the sagittal suture are:

(a) Lamba.

(b) Bregma.

12. Write the dental formula of permanent teeth?

Ans: The dental formula of permanent teeth:

13. Name the two main parts of human skull?

Ans: The two main parts of human skull are: cranial part and cranium.

14. Name the different parts of the innominate bone?

Ans: The different parts of the innominate bone are: ilium, ischium and pubis.

15. Name the bones that constitute the forearm and the leg?

Ans: The bones that constitute the forearm are radius and ulna.

The bones that constitute the leg are femur, tibia etc.

16. Name the different shaped bones in the human skeleton? Give example.

Ans: The different shaped bones in the human skeleton are:

(a) Long bone: Eg. Femur.

(b) Short bone: Eg. Carpals.

(c) Flat bone: Eg. Ribs.

(d) Irregular bone: Eg. Vertebrae.

(e) Sesamoid bone: Eg. Patella.

17. Write short notes on:

(a) Cranium.

Ans: In the cranium there are eight bones and fourteen bones in the facial part. The skull appears to be one large bone but in reality it consist of twenty two bones that connect together by sutures. A suture is a type of fibrous joint or synarthrosis that only occurs in the skull. The highest point in the skull is called the vertex. The vertex is formed by the frontal bone, two parietal bones and occipital bone of the cranium. The eight of the cranium are- Frontal, two partial bones, two temporal bones, occipital, Sphenoid and Ethmoid; they are all joined together by suture. 

(b) Mandible.

Ans: The mandible forms the lower jaw of the skull and holds the lower teeth. The joint between the mandible and temporal bones is known as temporomandibular joint, forms the only non sutured joint in the skull. Mandible is the largest , strongest and lowest bone in the human facial skeleton. The bone consist of a body which is curved and the forward pointed part gives the structure of the chin. The ramus of the mandible contributes to the lateral portion of the mandible on either sides. The coronoid process is situated anteriorly and condyloid posteriorly at the superior aspect of the ramus. The mandibular notch is located between the two processes. The body ends and the rami begin on either sides at the angle known as gonion angle of the mandible. The alveolar border of the body contains sixteen sockets to hold the root of the teeth. 

(c) Vertebral Column.

Ans: The vertebral column or back bone in the human skeleton extend from the base of the foramen magnum to the peloic girdle. The vertebral column is not a single bone but composed of thirty three bones or vertebrae situated one above the other. In between two vertebrae there are fibro cartilaginous plate called inter vertebral disc which allow slight movement between the vertebrae. Of the thirty three vertebrae twenty four are movable called primary or true vertebrae and the other nine are fixed called false vertebrae. Vertebral body and vertebral arch are the two parts of a typical vertebrae and both enclose together to form the vertebral foramen, through which the spinal cord passes.

The first cervical vertebrae of the vertebral column is the altas and second is the axis. The first seven vertebrae are called cervical vertebrae, next twelve are thoracic vertebrae which form the back of the body. The size of the thoracic vertebrae increases as they descend towards the next five lumbar vertebrae, which are bigger than the thoracic vertebrae. The next five are sacral vertebrae which are separated during childhood by carilage and latter fused to a single bone to form the sacrum. The final region of the vertebral column usually composed of four caudal vertebrae sometimes three or five called coccyx during childhood they form separate bone.

The vertebral column presents four curves and resemble somewhat’s shaped as the cervical curve is convex forward, the thoracic one is concave forward, the lumbar is convex while the pelvic curve is again concave forward.

(d) Ribs.

Ans: In the human skeleton there are twelve pairs of ribs, twelve each on right and left side of the sternum. The first seven set of ribs are attached to the vertebral column at the back and at the front with the sternum individually by carilage called true ribs. The next three set of ribs are connected to the thoracic vertebrae and collectively by carilage with the sternum at the front called false ribs. The last two set of ribs are only connected to the thoracic vertebrae but din not have an anterior attachment with sternum and remain free called floating ribs. The ribs forms a protective rib cage that protects the lungs, heart and other organs of the thoracic cavity.

(e) Femur.

Ans: The femur or thigh bone is the largest and strongest bone present between the hip and knee joint of the human skeleton. It consists of a proximal end, shaft and distal end. The proximal end comprises of a rough spherical head, neck, greater trochanter on the lateral side and lesser trochanter on the medical side and between the two trochanters is the intertrochanteric line. The distal end is broad and present the medial condyle and medial epicondyle in the medial aspect and lateral condyle and lateral epicondyle to the lateral aspect. In between the two condyles there is the patellar surface on the anterior aspect and pastewriorly is the intercondyler fossa. The shaft of the femur shows a forward convexity. On the posterior surface of the shaft is a rough ridge called linea aspera which is the site of attachment of muscles and distally is the triangular popliteal surface.

(f) Norma frontalis.

Ans: The Norma frontalis is more or less oval and wider above than below. From this aspect of the skull Frontal, nasal, zygomatic, mandible, maxilla vomer, lacrimal, orbits, rhinion, glabella, nadion, frontonasal suture, intra nasal suture, inter maxillary suture, fronto maxillary suture, zygomatic maxillary suture, fronto maxillary suture, nasomaxillary suture, frontozygomatic suture are seen.

(g) Norma lateralis.

Ans: The Norma lateralis of the skull presents the frontal parietal, nasal, lacrimal, temporal, zygomatic, maxilla, mandible, coronal suture, temporal suture, occipital suture etc.

(h) Humerus.

Ans: In the human skeleton, the bone of the arm is the humerus. It is long bone with three parts- proximal extremity, distal extremity and the shaft. The proximal extremity consists of head, neck, greater tuberosity, lesser tuberosity and between the two tuberosities is a deep groove called the bicipital groove. The hemispherical and smooth head of the humerus articulates with the glenoid cavity of the scapula. The distal end of the humerus is broad and flattened with medial and lateral epicondyle projecting on either sides. At the medial partion of the distal end is the trochlea, and lateral to it is the capitulum. A slight depression above the capitulum is the radial fossa and above the trochlea is the coronoid fossa in the anterior surface and olecranon fossa in the posterior surface. A rough elevation on the middle of the shaft is the deltoid tuberosity.

(i) Pelvic girdle.

Ans: The pelvic girdle is formed by two in nominate bones joined posteriorly to the sacrum of the vertebral column and anteriorly at the public symphysis. Each innominate bone comprises of three parts namely ilium, ischium and pubis. They fuse together to form a cup shaped socket on the anterolateral side of the innominate called the acetabulum where the head of the femur articulates. The expanded, fan shaped ilium includes the upper part of the acetabulum. The ischium is the part of innominate below and behind along with the lower part of acetabulum. The pubis is the most anterior portion of the innominate bone. The thick, curved area at the top of the ilium is the iliac crest. The obturator foramen created by ischium and pubis through which nerves and blood vessels pass.

(j) Human teeth.

Ans: Human teeth are made up of hard substances which helps to break down items of food by cutting and crushing them for preparing the food to swallow and digest. Human develop two sets of teeth; The first set is primary or deciduous or milk teeth. They start to appear around six to seven month of age. All primary teeth are later replaced with their permanent counterparts. Some babies are born with one or more visible teeth called natal teeth and the teeth that erupt during the first month of life are neonatal teeth. 

Among primary teeth, ten are found in maxilla and ten in the mandible far a total of twenty, where in each jaw there are four incisors, two canines and four molars. Premolar teeth is not present in primary dentation. On both sides of gits centrally located incisors there is one canine and after the canine there are two molars on each side.

(k) Hand.

Ans: The human hand consists of twenty seven bones arranged in three groups that include the carpus, metacarpus and phalanges. The carpus consist of eight carpel bones which include navicular, lunate, triquetral, pisiform, trapezium, trapezoid, capitate and hamate organized into two rows. The distal end of the radius bone of the forearm articulates with navicular and lunate bones of the carpus which help in the movement of the wrist. The metacarpus comprises of five bones. The bones of the phalanges are fourteen in number. Each finger has three phalanges except for the thumb which has two phalanges.

(l) Foot.

Ans: The human foot consist of twenty six bones divided in three groups that include the tarsus, metatarsus and phalanges. The tarsus consist of seven tarsal bones which are talus, calcaneum, medial cuneiform, lateral cuneiform, intermediate cuneiform, cuboid and navicular. The talus articulates with the tibia and fibula to form the ankle joint. The metatarsus comprises of five metatarsal bones. The bones of the phalanges are fourteen in number. Lateral four toes  are made up of three phalanges while the big toe comprises of two phalanges.