Human Muscular and Skeletal Systems

The Human Muscular and Skeletal Systems Assignment

Question 1

Our skeleton accounts of around 15% of our total body mass, skeletal muscle and other connective tissues up to 40%.

A) Analyze the overall structure and function of the different parts of the skeletal system, using diagrams to aid your analysis if you wish.

The skeletal system is comprised of 206 bones and this system can be divided into two parts:

1. Axial skeleton system which comprises 80 bones. It is made up of a rib cage, the skull, and the vertebral column or spine (Mukund & Subramaniam, 2020). The function of the axial skeleton is to maintain the upright posture of the individual as it transmits the weight from the upper edges (head and thorax) to the lower edges.
2. Appendicular Skeleton contains 126 bones, approximately and it contains the pelvis, upper limbs, and lower limbs (Zhang, Liu & Zhang, 2021). The function of the appendicular is to provide mobility and flexibility during walking and movement and protect the organs.

As a whole, one of the important functions of the skeleton system is the production of white and red blood cells in the bone marrow. Additionally, another important function of the skeleton muscle is:

1. Protection of internal organs from damage.
2. It gives shape by determining the height, width, and dimension of hands and feet (Kim et al. 2020).
3. It provides balance to the body by keeping the internal organs in the right position.

(Figure 1: Skeleton System of Human)

(Source: Pileggi, Parmar & Harper, 2021)

B) Describe and explain the 5 types of bones, using diagrams to aid you if you wish. Make sure that you explain the purpose of each bone type and give an example of where they are

1. Long Bone: this bone has a cylindrical shape and comprises with diaphysis and two bulky ends which are known as epiphyses. The appendicular skeleton is made up of long bones. The main function of this bone is to enable the movement (Kim et al. 2020). Some examples of long bones are upper limb bones like the humerus, and ulna, lower limb bones like the tibia, fibula, and demur, metacarpals, metatarsals, and phalanges in both figures.
2. Short bones: these bones are cube-shaped and comprise spongy bone and bone marrow, which provide a cuboid shape to the bone. The short bone offers stability and facilitates movement (Mukund & Subramaniam, 2020). Examples of small bones are: Tarsal bones, Carpel bones (lunate, hamate, capitate, and trapezium)
3. Flat bones: these bones are curved in shape and thin, which protect the internal organs like the heart, urogenital organs, and brain from harm and offer a broad surface for the attachment of a muscle (Lattari et al. 2020). Examples of flat bones are scapula ribs, and cranial bones like occipital, frontal, and vomer.
4. Irregular bones: these bones are complex in shape and used to protect the internal organs from harm. 33 vertebrae, pelvic bones, and crania bones are examples of irregular bones
5. Sesamoid bones: these bones are embedded in tendons and used to protect the tendons from regular tears by reducing friction. Examples of sesomoid bones are kneecaps, and pisiform bones located in the carpus.

(Figure 2: Types of bones)

(Source: Pileggi, Parmar & Harper, 2021)

C) Bones for joints to allow different ranges of Complete the table below by: -

1. Explaining the range of movement possible at each type of
2. Giving an example of the type of joint in the

Type of joint	Range of movement	Example of type of joint in the body
Fixed	No Movement	Skull- it is made up of fused bones
Pivot	Rotation around the central axis	Neck and forearm
Hinge	Movement in one plane	Elbow joints
Ball and socket	Rotate and turn in any direction	Shoulder and hips

 

D) Joints are held together by connective tissue including cartilage, ligaments, and Describe and explain the functions of each of these connective tissues within a joint.

Cartilage: Cartilage is flexible connective tissue that is made up of chondrocytes that give cartilage physical stability. The function of cartilage is to provide support and cushion the joints as it helps to maintain certain structures in the body (Pileggi, Parmar & Harper, 2021). Cartilage can be divided into three categories: elastic cartilage, fibrocartilage, and hyaline cartilage.

Ligaments: Ligaments are made up of connective tissues which connect one bone to another. The ligaments are made up of collagen fiber, which provides stability to the joints and prevents the dislocation of bones (Zhang, Liu & Zhang, 2021). Additionally, ligaments provide mobility to the joint. The knees are comprised of four ligaments which help knees to move side by side and backwards or upwards.

Tendons: Tendons are connected to muscle to bone. It is made up of collagen fiber, and within the tendon, three fibers are arranged in parallel bundles which give strength to the structure. The function of the tendon is to provide flexibility and withstand large stress (Mukund & Subramaniam, 2020).

Question 2

The image below shows an athlete during a weight training session.

A) Explain the class of lever system in use when the performer moves from standing onto her

When a performer moves from standing onto her toes, it involves the use of a second-class lever system. In this lever system, the load is located between the fulcrum and the effort. The weight at the toes acts as the fulcrum, and the calf muscle supplies the upward effort and here the body weight acts as the downward load (Boyce & Schoenfeld, 2022). In this process, the gastrocnemius muscle plays an important role, in terms of contraction this muscle provides an upliftment energy of the heel, and the Achilles tendon pulls the heel to raise the entire body upward. This mechanism falls under the example of a second-class level mechanism in the human body.

Explain why this gives the athlete mechanical advantage. You may use diagrams to aid your explanation if you wish.

Considering the mechanism of the second-class lever system, it can be stated that this mechanism provides mechanical advantages to the athlete by allowing the calf muscle to generate greater force to uplift the body without much effort. Thus, the athlete can get flexibility and efficacy in the movement (Boyce & Schoenfeld, 2022). More specifically, it can be stated that the effort arm is larger than the load arm which provides mechanical advantages with relatively small efforts.

(Figure 3: Second-class lever)

(Source: Ulbrich et al. 2020)

B) Explain two different examples of levers in a sporting situation of your choice. These must be different classes of levers to the lever system explained in part (a).

Two examples of different classes of lever in athletic scenarios are:

1. First-class lever: A common example of the first-class lever in sports is the neck while raising the head in football. The neck muscle provides the effort, therefore it is the fulcrum, and the weight of the head can be defined as load (Ulbrich et al. 2020).
2. Third-class lever: Biceps can be considered as an example of a third-class lever system. Here the fulcrum is the elbow joint and effort comes from the contraction of biceps and resistance comes from the forearm can be considered as the weight required to hold something (Lattari et al. 2020).

(Figure 4: Different types of levers)

(Source: Lattari et al. 2020)

Question 3

The image below shows the muscular system whilst running.

Complete the table below by:

A) Identifying the muscles labelled A, B and C in the image
B) Outline the role of each

	a) Muscle	b) Role of Muscle
A	Biceps	The location of the biceps is in the front of the upper arm. It is responsible for flexing the elbow and rotation of the forearm (Mukund & Subramaniam, 2020). It also stabilises the arm and shoulder while running.
B	Hamstrings	It locates at the back of the thigh and between the knees and hips. It helps in hip extension and flexion of the knee. It also helps in thigh extension and helps to move the upper leg backward during running.
C	Calf muscles	During running, the calf muscles are located at the back of the lower leg, and are responsible for plantar flexion, which helps to move the feet away from the field. It also helps to stabilise the ankle and foot while running (Glancy & Balaban, 2021) .

C) Explain the structure of striated (skeletal muscle) and compare the muscle structure in areas of the body that move frequently to those that move less frequently.

Striated muscle is made up of long, and cylindrical muscle fibers and located in various parts of the body, including the neck, hands, feet, and tongue. The Striated muscle or skeletal muscle can be defined as the tissue that helps the muscle to be attached to the bone. It is voluntary and facilitates the voluntary movement of the bones (Powers et al. 2021). On the other hand, cardiac muscle is involuntary and found at the walls of the heart. Both the skeletal muscle and cardiac muscle have a striated appearance due to the presence of myofibrils (Morris, Zawieja & Moore Jr, 2021). Unlike the striated muscle, smooth muscles are involuntary in movement and its arrangement in the cell facilitates the relaxation and contraction of the muscle and provide elasticity.

(Figure 5: Structure of Skeletal, Striated Muscle)

(Source: Sasikumari, 2020)

D) Use the sliding muscle filament theory to explain the molecular mechanisms behind muscle contraction in these types of You may use diagrams to help you if you wish.

The sliding filament theory- this theory was propounded by A.F. Huxley and R. Niedegerke (1954). According to their observation, in one zone, the repeated sarcomere has formed an arrangement that can be referred to as “A Band”, which is constant in length during the contraction (Zhuge et al. 2020). The I band is rich in thinner filament which is made up of actin and myosin. According to the theory, sliding of actin and myosin can generate muscle tension, and actin located at the adjacent end of the sarcomere forms the “z-disc-like structure”, which can be called a Z-band (Saxton, Tariq & Bordoni, 2023).  Considering this theory, it can be stated that in muscle contraction, the thin filament of action slides over the myosin, and this sliding facilitates the formation of a cross-bridge structure. In this structure, myosin heads undergo through a power stroke which causes the filament to slide over and cause shortening of the sarcomere and muscle fiber. During this time, the myosin filament is attached to the “M-line” at the center of the sarcomere whereas the actin filament is anchored to the “Z-line” at the end of the sarcomere and undergoes through conformational changes (Dong, Ma,  & Guo, 2020).

(Figure 6: Sliding Muscle Filament theory)

(Source: Dong, Ma & Guo, 2020)

E) Other than skeletal muscles, there are two other types of muscles in your body. Outline these muscle types, their structure, and their

Apart from the skeletal muscle, there is cardiac muscle and smooth muscle. The Cardiac muscle is accountable for the pumping in and out of the blood throughout the body. The movement of this muscle is involuntary and cardiac muscle is striated, and has a unique branching structure that can allow the cardiac muscle to pump in and out of the blood throughout the body simultaneously (Sasikumari, 2020).

On the other hand, Smooth muscles are located at the walls of the internal organs like the stomach, intestine, and blood vessels. Like Cardiac Muscle, Smooth muscle is also involuntary, but it is not striated. The shape of Smooth Muscle is spindle-like and arranged in a layer which can allow the muscle to contract and relax in a coordinated way (Saxton, Tariq & Bordoni, 2023). 

Question 4 

The above X-ray image shows a gymnast. Many gymnasts begin training at a very young age and this can impact bone development in both positive and negative ways.

A) Explain how bones grow and develop and suggest how training as a gymnast can affect bones whilst physically training and living on a calorie restricted You may use diagrams to help you if you wish.

The process involving the growth and development of bone is known as ossification. The osteogenesis mainly occurs in two ways: intramembranous and endochondral.

The Intramembranous process facilitates the formation of primitive connective tissues. this process is also followed for the formation of flat bones in the skull, jaw, and clavicle (Salhotra et al. 2020). These bones are shaped flat during the formation and comprise with membrane-like layers of connective tissues that foster the blood supply. Therefore the processes involved are:

1. The ossification center appears at the mesenchymal tissue
2. The existing mesenchymal cells form the template for bone formation.
3. The osteoblasts secrete the extracellular matric and remove the calcium ion from blood and then it is deposited within the tissues which causes the hardening of the tissue., this process is known as mineralization (Miyazaki et al. 2022)
4. The non-mineralised bone forms round the blood vessels that in turn facilitate the development of spongy bines, and the mesenchyma tissues are started to condense to, the periosteum or bone covering.

On the other hand, the endochondrial process uses the hyaline cartilage for the formation of long bones.

1. The first ossification center forms in the middle of the cartilage. At that time calcification started at the center of the cartilage which makes the area nutrient-rich.
2. Secondary ossification centers are developed at each end of the long bones which form the epiphyseal plates.

Training as a gymnast has positive as well as negative impacts on bone health. Gymnasium is related to the repetitive loading of bones which stimulates bone growth and density. On the other hand, a calorie-restricted diet can risk the onset of osteoporosis, a condition that can be defined by low bone density and the onset of fracture in the bone (Eckers, Fischer & Tscholl, 2020). On the other hand, calorie restriction can cause a reduction in the level of testosterone and estrone hormone in blood which play important roles in the formation and maintenance of bone.  Therefore, to maintain bone health during the training period for gymnasts, it should be important to consume a balanced diet that is rich in nutrients for bone growth and development.

B) Gymnasts can, from time to time, injure bones. Explain how bones repair when You may use diagrams to help you if you wish.

The first step of repairment of a fractured bone is the formation of the blood clot at the site of injury, which in turn can help to stabilise the bone and facilitate the mending processes. At that time, the body started the disposition of Calcium on the blood clots which turns into the soft callus. From this time, osteoblast and osteoclast are started to form (Bonazza et al. 2022). The osteoblast is the large cell that is responsible for the creation and laying down of minerals in bone, both at the time of the first formation of bone and later when the bone starts to change its structure throughout life (remodeling) (Makovitch & Eng, 2020). Osteoclast refers to the cells that are responsible for the breakdown and reabsorption of the bone tissues. The healing process takes several days or weeks or even several months based on the severity of the injuries or fractures. During this time, the bones started to reshape and strengthen through remodeling (Gissi et al. 2020). It involves the removal of the old bone tissues by the osteoclasts and the deposition of the new bone tissues by the osteoblasts.

(Figure 8: Bone Injuries for Gymnasts)

(Source: Gissi et al. 2020)

C) Wear and tear on bones and joints are common in high-intensity and repetitive sports training. As athletes grow older or possibly become ill, this becomes a bigger problem. Explain the effects of old age and disease on

In old age, the bone joints are affected by the sudden changes in connective tissues and cartilage. The cartilage inside the joint becomes thinner and components of the cartilage which can also be known as proteoglycans become changed, which makes the joints more prone to fracture or damage (Makovitch & Eng, 2020). Additionally, in old age, the connective tissues within the ligaments and tendons start to become rigid and brittle, which makes the joint stiff and fragmented. Loss of muscle, which can be termed as sarcopenia starts at the age of 30 and remains throughout life. In this process, the number of muscle tissues and the size of the muscle fibers started to decrease and cause loss of muscle mass and strength (Gissi et al. 2020). Some diseases like rheumatoid arthritis and osteoporosis cause inflammation at joints and reduce bone density, which in turn alleviates the fracture in the bone.