The Human Muscular-Skeletal System

Terms of Reference

This report skeletal and muscular systems. It looks at terms of autonomy, the composition of the skeletal and muscular systems and how they work together.

Contents page

Terms of reference          page 2

Research Methodology        page 4

Findings         page 5

1.1 Anatomical Terminology      page 5

1.2 Human Systems        page 6

2 Skeletal system        page 7

2.1 Bones         page 8

2.2 Joints         page 10

2.3 Muscular forces on the skeletal system     page 11

3  Muscular System         page 12 

3.1 Muscle Movement        page 13

Conclusion         page 14

Recommendations        page 15

References         page 16

Research Methodology

Research has been undertaken through sourcing information in different ways to understand the skeletal-muscular system. Reading library books, websites and watching videos has enabled a clear understanding of the subject.

Findings

1.1 Anatomical Terminology

Anatomical terminology describes the movements and points of a human body both externally and internally. See images and table below:

Serario

Description

Arm movements Pouring drink and sipping it

Arm flexion and internal rotation moving anterior through adduction towards the sagittal plane.

Arm move supination lateral to sagittal plane. Arm extension placing carton down.  Arm moves anterior and adduction to sagittal plane. 

Arm flexion moving superior through horizontal plane along vertical axis. Once proximal to the lip’s wrist pronation to sip

Walking upstairs

Flexion hip and knee anterior medial towards medial plane. Foot dorsal flexion reaching step. Once on step right foot planter flexion. Hip and knee extension lateral to straightening leg. Alternative leg repeats process.

Location of nose to belly button

Nose is superior to belly button, anterior along sagittal axis. Belly button is proximal to horizontal plane. Nose is distal from horizontal plane.

Heart location to Liver

proximal superior Medial towards sagittal plane

Heart location to Appendix

left medial distal

Heart location to Lungs

left medial distal

Heart location to Bladder

superior, distal along the sagittal plane

1.2 Human Systems

The body’s a complexed multicellular system organised at different levels starting with cells and ending with the whole body. Like a pyramid each layer links together to form a complete structure.

Over 200 different cells form the foundation. Some are more present than others i.e.  Fibroblasts adipocytes and Leukocytes.

Cells form together to make tissues. There are four basic tissue types: epithelial, muscle, nerve and connective. Each perform specialist roles i.e Muscle tissue contains cells that contract and enable movement.

Similar tissues form together creating organs. Organs systems work together to form the whole body.

The below table shows how the hierarchy of cells, tissues and organs form the circulatory system:

Cells

Tissue

Organ/ structure

Function

Fibroblasts i.e. Collagenous, elastic fibres

Collagen and Endothelium

Veins and Arteries

Creates a network to enable blood and nutrients transfer

myofibrils

Smooth Muscle

Veins and Arteries

Aides pumping of blood through body

myofibrils

Cardiac Muscle

Heart

Pumps transferring blood and nutrients to body

2 Skeletal System
The skeletal system supports shape and form. Protects vital organs (i.e. brain, spinal cord and heart) Provides movement, Store’s nutrients and produces blood cells. It’s composed of connective tissues including bone, cartilage, tendons, and ligaments (Bailey, 2018).

Ligaments and Tendons are both Dense regular connective tissue consisting of Type I collagen (higher in tendons), lipids, elastin (higher in Ligaments),Proteoglycans, fibroblast. The difference in elastin and collagen fibres enables ligaments to support internal organs or hold bones / joints together in proper articulation and Tendons to transmit force to bones.

Cartilage is  composed of chondrocytes  producing high amounts of  collagenous extracellular matrix,  proteoglycan and elastin fibers. There’s three types with varying amounts of collagen and proteoglycan, elastic cartilage (most flexible it, ie ear), hyaline cartilage  (most common with medium flexibility) and fibrocartilage least flexible, located between vertebrae and the knee joint (wikipedia, 2018)

Periosteum consists of Outer, fibrous periosteal layer consisting of dense irregular tissue; collagen (type I), elastin fibers, and fibroblasts. Inner osteogenic layer consists of progenitor cells (develop into osteoblasts). (Modric, n.d.). Covers most bones enables ligaments and tendons to attach at insertion sites. Attaches to bone through sharpies

2.1 Bones

Osteogenesis has different stages depending on the type of bone being created. See below:

Stage

Intramembranous

Endochondral

1

ossification centre appears in the mesenchymal tissue

Periosteum forms around a hyaline cartilage. Cartilage becomes highly vascularised from infiltrating blood vessels changing mesenchymal cells to osteoblasts. Osteoblasts secrete organic fibres onto the outside of the cartilage causing collar formation.

2

Bone template is formed from mesenchymal cells which differentiate into osteoblasts.

Primary ossification centre forms in the middle of the cartilage. Calcification begins at the centre of the cartilage making it impermeable to nutrients, causing deterioration of this area forms the medullary cavity.

3

Secreted osteoid traps osteoblasts, which then become osteocytes

Blood vessels from the periosteum enter the inner cavity of cartilage/bone supplying nutrients, bone forming cells and nerves, causing the bone to elongate.

4

Non-mineralized bone forms around blood vessels forming spongy bone.

Secondary ossification centres form at each end of the bone forming the epiphyseal plates. Epiphyseal plates allow growth after birth

5

mesenchyme tissue condenses around the newly formed bone forming the periosteum

Hyaline cartilage remains at the epiphyseal surface and the epiphyseal plate.

The skeleton consists of 206 bones, divided into two parts (image below)

The Axial Skeleton (80 bones) maintains upright posture, transmits weight between upper and lower extremities i.e. vertebral column, skull. The Appendicular skeleton (126 bones) protects organs and performs motion i.e. limbs and pelvis.

(Wiley, J, ND)

The bone shape depends on the function There are 5 types of bones:

Irregular

Have irregular shapes due to functions in the body. i.e. provides mechanical support and protection.

vertebrae and sacrum

Short

Are approximately cube shaped i.e. similar width, depth and length. Provides stability and support

 Wrist and ankle

Flat

Are thin shaped. Provides protection to organs or extensive surface for muscle attachment (shoulders)

Skull, Ribs and shoulders

Sesamoid

Located where tendons undertake considerable stress, friction and tension. Provides smooth surface for tendons to mover over

Patella

Long

Are longer than they are wide. Provide movement.

legs and arms

2.2 Joints

Joints are classified by the type of material present and level of movement provided. The three primary joints are:

Fibrous fixes bones together. I.e. the skull.

Cartilaginous consist of fibrocartilage and hyaline binding bones together limiting movement. i.e. between intervertebral disks.

Synovial joints are free moving lubricated with synovial fluid reducing friction and wear.  Surrounded by a capsule with a smooth lining of synovial membrane. Is strengthened by ligaments. The six types of synovial joints:

Joint

Motion

Ball and Socket

Enables large movement range. Incudes a ball-shaped surface on one end and a cup-like shape on the other i.e. the shoulder and hip joint.

Condyloid

have an irregular surface. i.e. jaw or distal metacarpals

Hinge

allow movement in one plane without sliding. i.e. the elbow joints.

Gliding

Enables gliding/ sliding movement. i.e. the carpels of the wrist

pivot

one bone rotates around the other. Allows turning motion i.e. atlantoaxial joint

Saddle

two bones fit together like a rider in a saddle. Enable bending motion. i.e. thumb joint.

2.4 Muscular forces on the skeletal system.

Force from muscular contractions pulls on tendons attached to muscles. Tendons transfers the force to the bone via its attachment to the periosteum.  The force must be enough to overcome resistance for movement.

Joints work like levers. A lever consists of a rigid “bar” that pivots around a stationary fulcrum. i.e  fulcrum = joint, bones = levers, skeletal muscles = motion (Jensen, ND)

(Jensen, ND)

The three types of levers:

First-class lever – fulcrum based in the middle. Effort and load at either end. i.e. lifting head off the chest.

Second-class lever – load in the middle. Effort and fulcrum at either end. i.e. standing on tip toes.

Third-class lever – effort in the middle, fulcrum and load at either end. I.e. bending the Elbow

3 Muscular System

The muscular system enables, motion, movement and produces heat.

The body contains over 600 muscles performing individual roles. There’s three muscle categories, Cardiac, Smooth and skeletal. Each formed differently depending on function

Muscle Type

Description

Location

Smooth

fibres are spindle- shaped and can have a single, usually centrally located nucleus (i.e. single-unit) or can consist of discrete units that function independently of each other. Under the control of the autonomic nervous system

In the walls of hollow organs such as the uterus, bladder and blood vessels

Cardiac

fibres are arranged in an interlocking patter, ensuring each fibre is contacting may others to form a network. The intercalated disk is at the end of each fibre forming a junction between fibres to give strength and ensure they don’t separate. It also allows are nerve impulses to stimulate quickly

Heart

Skeletal

Voluntary muscle and are used for movement. Skeletal muscle fibres are cylindrical shaped and has many nuclei. Muscles varies in shape and size. Hundreds of muscle fibres are grouped together and wrapped in a connective covering called the epimysium. Each fibre contains 4-20 myofibrils containing myofilaments

Arms, legs, face etc

3.1 Muscle Movement

Muscles only contract and must work in pairs or groups. The primary mover is the contracting muscle making the movement. The antagonist is the muscle that opposes the action. The synergist muscle supports I.e. flexion the elbow the biceps are the primary mover and triceps the antagonist. Brachialis the synergist.

Sliding filament Theory

Myofibrils have sarcomeres repeating along its length. Each myofibril contains smaller structures called thick (Myosin) or thin (actin) myofilaments. Muscles contract by:  

nervous impulse enters the neuromuscular junction, releasing Acetylcholine (ATP) causing the depolarisation of the motor end plate. This travels throughout the muscle by transverse tubules, causing Calcium to release from the sarcoplasmic reticulum.

Calcium binds to Troponin and Tropomyosin removing from the Actin. Myosin filaments attach to the Actin, forming a cross-bridge.

The breakdown of ATP releases energy enabling the Myosin to pull the Actin filaments inwards shortening the muscle.

Once the impulse stops the Ca+ pumps back to the Sarcoplasmic Reticulum. The Actin returns to its resting position. The muscle relaxes.

Conclusion

The Human muscular skeletal system, is important in supporting life, enabling movement, motion, protection and blood cell production. Without movement the body could seek food and eat it. Without protection organs are liable to damage and blood cell production helps to support the whole body. 

Recommendations

To develop further knowledge of the muscular skeleton system by reviewing the individual muscles of the skeleton.

References

1.2 Structural Organization of the Human Body

6.4 Bone Formation and Development

TeachPE Ltd, 2017Muscle Contraction & Sliding Filament Theory, accessed 16/10/2018

www.teachpe.com/anatomy/sliding_filament.php

St Georges University, 2006, accessed 23.10.2018 available at: i.pinimg.com/originals/38/4d/b8/384db821c5b96442c2a7faec8fbc593f.jpg

Wiley, J, ND, accessed 23.10.2018 available at: i.pinimg.com/originals/01/7c/b5/017cb599205ddcdcb17f203c912d84c6.png

Lumen, Nd, Development of the skeleton, accessed 18.10.2018 available at: courses.lumenlearning.com/boundless-ap/chapter/development-of-the-skeleton/

Jensen, K, ND, Musculoskeletal System accessed 24.10.2018 available at:  www.biologyreference.com/Mo-Nu/Musculoskeletal-System.html

Modric, J, ND, Periosteum accessed 27.10.2018 available at: www.eheakthstar.com

Wikipedia, 2018, Tendon accessed 27.10.2018 available at: en.wikipedia.org/wiki/Tendon

Wikipedia, 2018, Cartilage, accessed 27.10.2018 available at; en.wikipedia.org/wiki/Cartilage

Woon,c & Moore, C, Nd, Tendons, accessed 27.10.2018 available at; www.orthobullets.com/basic-science/9016/ligaments