support and movement test 2

• The sarcomere is the basic functional unit of a muscle fiber.
• It spans between two consecutive Z-lines in a myofibril, as depicted in anatomical diagrams.
• Therefore, the correct answer is B, "Z-lines".

• The pectoral girdle, also known as the shoulder girdle, is a complex structure made up of several bones.
• These bones include the clavicle, or collarbone, and the scapula, or shoulder blade.
• Thus, the correct answer is C, "Both".

• The human body is structurally divided into two parts: the axial skeleton and the appendicular skeleton.
• The total number of bones in the axial skeleton is 80, making B the correct answer.

• The mammalian skeleton is primarily divided into two sections: the axial and the appendicular skeleton.
• The appendicular skeleton comprises the bones of the upper limbs (arms), lower limbs (legs), and the girdles (shoulders and pelvis) that connect them to the axial skeleton.
• Therefore, the correct answer is A, "Appendicular skeleton".

• In a contracting muscle, the H-zone disappears, and I-band shortens.
• However, the length of the actin and myosin filaments remains the same.
• This is because the actin filaments slide past the myosin filaments towards the middle of the sarcomere.
• Thus, the correct answer is C, "Remains same".

• A myofibril is a cylindrical organelle that spans the length of the muscle fiber and contains actin and myosin filaments.
• The area from one Z-band to the next Z-band in a myofibril is referred to as a sarcomere.
• Therefore, the correct answer is D, "Sarcomere".

• Muscles in the human body can be categorized into three types: cardiac, skeletal, and smooth.
• Among these, only smooth muscles are non-striated, meaning they do not have stripes.
• Thus, the correct answer is C, "Smooth muscles".

Arthritis is a comprehensive term used in medicine.

It is primarily associated with inflammation that occurs in the joints.

Therefore, the right answer is B, "Inflammation of joints".

The human spine is divided into distinct sections: cervical, thoracic, lumbar, sacral, and coccyx.

The cervical section has 7 vertebrae, and the thoracic section contains 12.

Adding these up gives a total of 19, so option B is correct.

Muscle contraction necessitates a substantial amount of energy.

When the primary energy source is depleted, the body turns to secondary sources.

One such source is Phosphocreatine, also known as creatine phosphate, making option C the correct answer.

The human skull, which protects the brain, is comprised of several bones.

These bones are intricately joined together, allowing for minimal movement.

The total number of bones in the human skull is 22, making option D the correct answer.

Bone formation is a complex process that involves several types of cells.

Osteoblasts are the cells primarily involved in the formation of new bone.

Therefore, the correct answer is A, "Osteoblast".

The human body contains many types of bones, each serving a different function.

The femur, or thigh bone, is the longest and strongest bone in the body.

It connects the hip joint to the knee joint, providing support and movement.

Therefore, the correct answer is A, "Femur".

Cartilage is a flexible connective tissue found in many areas of the human body.

There are three main types: Elastic, Fibro, and Hyaline.

Hyaline cartilage is the most common, found in the nose, respiratory tract, and joints, thereby making option C the correct answer.

A myofibril, a basic rod-like unit of a muscle, is made up of several bands and lines.

The H-zone is specifically located in the central part of the A-band.

Therefore, option A, "In the middle of the 'A-band'" is the correct answer.

Troponin plays a crucial role in the contraction of skeletal and cardiac muscles.

It has three subunits - TnC, TnT, and TnI. TnC binds to calcium ions, TnT to Tropomyosin, and TnI to actin.

Therefore, all the options A, B, and C are correct, making D the correct answer.

The human spine is a complex structure made up of different types of vertebrae.

The coccyx, often referred to as the tailbone, is located at the base of the spine.

It is typically composed of 3 to 5 vertebrae, but in most cases, it contains 4 fused vertebrae, making option D the correct answer.

The vertebral column, or spine, is divided into different regions: cervical, thoracic, lumbar, sacral, and coccyx.

The cervical region is the uppermost part of the spine and contains seven vertebrae.

The first cervical vertebra is called the atlas, thus making option D the correct answer.

Skeletal muscles, responsible for voluntary movements, have a complex structure.

Each muscle has three main parts: the origin (where the muscle attaches to a stable bone), the belly (the bulk of the muscle), and the insertion (where the muscle attaches to a bone that moves).

Therefore, the correct answer is C, "3".

Rigor mortis is a well-known postmortem change, resulting in the stiffening of the body muscles.

This process involves the actin and myosin proteins within the muscle cells.

It primarily occurs due to the unavailability of ATP, which is required to break the link between actin and myosin. Thus, option B is the correct answer.

Muscles and bones are linked together in the human body, forming the musculoskeletal system.

This connection is made possible by certain structures like ligaments, tendons, and connective tissues.

Specifically, tendons are the structures that attach muscles to bones at both ends, making option B the correct answer.

• The human body contains various types of joints, each allowing a certain degree of movement.
• The extent of motion varies among hinge, cartilaginous, fibrous, and ball and socket joints.
• The ball and socket joint exhibits the greatest flexibility and range of motion, thereby making D the correct answer.

• The human skeletal system is an internal framework that provides structure, support, and protection to our bodies.
• At birth, the body comprises around 270 bones. However, some of these bones fuse together as one grows, resulting in a decreased total number of bones in adulthood.
• The correct total number of bones in the adult human body is 206, therefore, option A is the correct answer.

• The human body contains various types of joints, each allowing a certain degree of movement.
• The extent of motion varies among hinge, cartilaginous, fibrous, and ball and socket joints.
• The ball and socket joint exhibits the greatest flexibility and range of motion, thereby making D the correct answer.

• The human skeletal system is an internal framework that provides structure, support, and protection to our bodies.
• At birth, the body comprises around 270 bones. However, some of these bones fuse together as one grows, resulting in a decreased total number of bones in adulthood.
• The correct total number of bones in the adult human body is 206, therefore, option A is the correct answer.

• Muscle fibers, also known as myocytes, contain several myofibrils.
• These myofibrils are made up of repeating protein structures, organized into thick and thin filaments, known as Myofilaments.
• This repeating unit is called a sarcomere, making option A the correct answer.

• The human skeletal system is divided into two major parts: the axial and appendicular skeleton.
• The axial skeleton includes the bones of the head and trunk, such as the skull, rib cage, and vertebral column.
• Among the given options, the ribs are part of the axial skeleton, making option B the correct answer.

• Muscle contraction, as explained by the sliding filament theory, involves complex interactions between actin and myosin filaments within the muscle fibers.
• The I bands, composed of actin filaments, are known to contract or shorten when muscle fibers are stimulated.
• Hence, the correct choice would be 'A. I-bands shorten'.

• The vertebral column, also known as the spine, is a complex structure composed of individually named vertebrae.
• Towards the end of the spine, the last four vertebrae fuse together to form a structure known as the coccyx.
• Therefore, the correct answer is 'C. Coccyx'.

• Bones serve as the structural framework for our bodies, and various structures work together to maintain the connectivity between them.
• Ligaments are the specific structures that perform the function of holding bones together.
• Thus, the correct response is 'C. Ligaments'.

The human body is composed of several muscular structures, each serving specific functions.

These muscles not only enable movement but also contribute to our body shape and regulation of body temperature.

Among the given choices, the most accurate approximation of muscles in the human body is around 650, making option D the correct answer.

The facial skeleton is made up of 14 bones, some of which are paired while others are unpaired.

Among the listed options, the vomer is an unpaired facial bone, making option D the correct answer.

The human vertebral column, often referred to as the spine, is a complex structure offering support and flexibility.

It is composed of individually named vertebrae, which are not paired but singular units.

The total number of vertebrae that make up the human vertebral column is 33, therefore option A is the correct answer.

The bone matrix is a sturdy framework that provides strength to the bone structure.

Certain substances contribute to the hardening of this matrix, allowing it to provide effective support.

Among the available options, calcium phosphate is the substance that hardens the bone matrix, making the correct response 'D. Calcium phosphate'.

The human body comprises various types of joints, each having a unique structure and function.

Ball and socket joints are a specific type that allow for a wider range of movement.

Among the provided options, the shoulder is an example of a ball and socket joint, marking 'C. Shoulder' as the correct answer.

Muscle contraction is a complex process involving the release and binding of various ions and proteins.

Specifically, during this process, calcium ions are released and attach to a particular protein.

In this context, calcium ions attach to the troponin protein, making 'D. Troponin' the right answer.

Muscle cells, also known as muscle fibrils, have a unique structure characterized by specific components.

The sarcolemma, which is the cell membrane of a muscle cell, folds inwards to form a particular structure.

In this context, the inward folds form a system of tubes called Transverse Tubules, so 'D. Transverse Tubules' is the correct answer.