Musculoskeletal System: Level 3 Biology Written Exam & Answers

This assignment provides detailed answers to questions related to the musculoskeletal system, covering muscle classification, structure, and contraction, as well as bone functions and joint types. It explains the structure of skeletal, cardiac, and smooth muscles and the process of muscle contraction involving calcium ions and actin-myosin binding. The solution identifies antagonistic muscle pairs like biceps-triceps and quadriceps-hamstrings, explaining their coordinated action. It also describes the functions of bones in providing structural support and protecting organs, comparing different bone types (short, long, sesamoid, irregular, and flat) and detailing the structure of a long bone. Furthermore, it elucidates the characteristics of fibrous, cartilaginous, and synovial joints, highlighting the features of synovial joints such as articular cartilage and synovial fluid, and naming six types of synovial joints with their respective movements. Desklib offers a platform where students can access this and many other solved assignments to enhance their learning.

Running head: BIOLOGY ASSIGNMENT
BIOLOGY ASSIGNMENT
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1BIOLOGY ASSIGNMENT
Answer 1
Cardiac muscles are present in the wall of the heart and the appearance of this muscle is
cylindrical and stripped. On the other hand, hollow visceral organs contain smooth muscles in
their wall and it looks spindle- shaped. Skeletal muscles that are attached to the skeleton of
human body, act upon voluntary control.
Answer 2
Muscle contraction is the process, that resulted by several cyclic events in which calcium
ions bring on a change in the troponin structure by revealing its site of binding for myosin which
ultimately binds to the actin sites. This binding further enhances the sliding movement of actin
which ultimately leads to muscle contraction.
Answer 3
Two antagonistic muscle pairs are Biceps-triceps and quadriceps and hamstring muscles.
While walking and running the hamstring contracts itself to flex the knee whereas, it requires the
quadriceps to lengthen so that the movement could be achieved. While picking objects bicep
contracts to bring the object nearer to the individual, in which situation, triceps expands to carry
out the movement, hence works under antagonist nature.
Answer 4
The primary role of bone in the human body in connected with providing the body with
structural support as well as helping the soft-tissues and organs within the human body to attach
to the structural framework, formulated with bones. Further, it also helps to protect important
organs such as heart, liver lungs and so on.

2BIOLOGY ASSIGNMENT
Answer 5
The five types of bones present in the human body are short, long, sesamoid, irregular
and flat. The flat bones are present in the skull, rib cages, pelvis, scapula, and work as a shield to
the internal organs, whereas, long-bones are associated with the formation of hands and legs.
Short bones are located in the joints of hands and legs and help to provide stability and
movement to the structure, whereas irregular bones form complex shapes in the spinal cord. The
bones, embedded within the muscle tendons are known as sesamoid bones and protect the joints
from external and internal stress.
Answer 6
The structure of long bone is consists of a tube-shaped shaft, known as diaphysis and also
two extremities known as the epiphysis. Further, it is a complicated bone structure where the
central medullary cavity is surrounded by bone structure.
Answer 7
The three types of joints are synovial, cartilaginous, as well as fibrous. The fibrous joints
do not have any cavity and hold the structure of the bones together. On the other hand,
cartilaginous bones are surrounded by cartilages that help it to move sequentially. The upper
surface of the synovial joints is covered with articular cartilage, which makes this type of joint as
the most movable joint.
Answer 8
The synovial joints are named as diarthrosis joints that consist of several unique features.
Presence of articular cartilage that helps it to move swiftly within bones, the presence of a joint

3BIOLOGY ASSIGNMENT
cavity, fibrous capsule and presence of synovial membrane with synovial fluid are the primary
characteristics of this joint.
Answer 9
The six types of synovial joints:
• gliding joints
• condyloid joints
• ball and socket joints
• Hinge joints
• Pivot joints
• saddle joints
Answer 10
While the pivot type of synovial joint helps them to move side to side, ball and socket
will help to provide rotator movement to the body. Pivot joints are found in the neck, ball and
socket joints are found throughout the body for rotator movement.