what are the three key functions of the human skeleton

Human skeleton, the internal skeleton that serves as a framework for the body. that the functions of the skeleton are of three different types: support. The two major divisions of the skeleton are the axial skeleton, Sample answer: Functions of the skeletal system include supporting the body. Each bone of the body serves a particular function, and therefore bones vary in This diagram shows the human skeleton and identifies the major bones.

: What are the three key functions of the human skeleton

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What are the three key functions of the human skeleton
What are the three key functions of the human skeleton

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The muscular system consists of various types of muscle that each play a crucial role in the function of the body.

Muscles allow a person to move, speak, and chew. They control heartbeat, breathing, and digestion. Other seemingly unrelated functions, including temperature regulation and vision, also rely on the muscular system.

Keep reading to discover much more about the muscular system and how it controls the body.

How the muscular system works

The muscles account for around 40 percent of a person’s weight with the largest muscle in the body being the gluteus maximus in the buttocks.

The muscular system contains more than 600muscles that work together to enable the full functioning of the body.

There are 3 types of muscles in the body:

Skeletal muscle

Skeletal muscles are the only muscles that can be consciously controlled. They are attached to bones, and contracting the muscles causes movement of those bones.

Any action that a person consciously undertakes involves the use of skeletal muscles. Examples of such activities include running, chewing, and writing.

Smooth muscle

Smooth muscle lines the inside of blood vessels and organs, such as the stomach, and is also known as visceral muscle.

It is the weakest type of muscle but has an essential role in moving food along the digestive tract and maintaining blood circulation through the blood vessels.

Smooth muscle acts involuntarily and cannot be consciously controlled.

Cardiac muscle

Located only in the heart, cardiac muscle pumps blood around the body. Cardiac muscle stimulates its own contractions that form our heartbeat. Signals from the nervous system control the rate of contraction. This type of muscle is strong and acts involuntarily.

Eleven main functions of the muscular system

The main functions of the muscular system are as follows:

1. Mobility

The muscular system’s main function is to allow movement. When muscles contract, they contribute to gross and fine movement.

Gross movement refers to large, coordinated motions and includes:

Fine movement involves smaller movements, such as:

  • writing
  • speaking
  • facial expressions

The smaller skeletal muscles are usually responsible for this type of action.

Most muscle movement of the body is under conscious control. However, some movements are reflexive, such as withdrawing a hand from a source of heat.

2. Stability

Muscle tendons stretch over joints and contribute to joint stability. Muscle tendons in the knee joint and the shoulder joint are crucial in stabilization.

The core muscles are those in the abdomen, back, and pelvis, and they also stabilize the body and assist in tasks, such as lifting weights.

3. Posture

Skeletal muscles help keep the body in the correct position when someone is sitting or standing. This is known as posture.

Good posture relies on strong, flexible muscles. Stiff, weak, or tight muscles contribute to poor posture and misalignment of the body.

Long-term, bad posture leads to joint and muscle pain in the shoulders, back, neck, and elsewhere.

4. Circulation

The heart is a muscle that pumps blood throughout the body. The movement of the heart is outside of conscious control, and it contracts automatically when stimulated by electrical signals.

Smooth muscle in the arteries and veins plays a further role in the circulation of blood around the body. These muscles maintain blood pressure and circulation in the event of blood loss or dehydration.

They expand to increase blood flow during times of intense exercise when the body requires more oxygen.

5. Respiration

Breathing involves the use of the diaphragm muscle.

The diaphragm is a dome-shaped muscle located below the lungs. When the diaphragm contracts, it pushes downward, causing the chest cavity to get bigger. The lungs then fill with air. When the diaphragm muscle relaxes, it pushes air out of the lungs.

When someone wants to breath more deeply, it requires help from other muscles, including those in the abdomen, back, and neck.

6. Digestion

The muscular system allows for movement within the body, for example, during digestion or urination.

Smooth muscles in the gastrointestinal or GI tract control digestion. The GI tract stretches from the mouth to the anus.

Food moves through the digestive system with a wave-like motion called peristalsis. Muscles in the walls of the hollow organs contract and relax to cause this movement, which pushes food through the esophagus into the stomach.

The upper muscle in the stomach relaxes to allow food to enter, while the lower muscles mix food particles with stomach acid and enzymes.

The digested food moves from the stomach to the intestines by peristalsis. From here, more muscles contract to pass the food out of the body as stool.

7. Urination

The urinary system comprises both smooth and skeletal muscles, including those in the:

  • bladder
  • kidneys
  • penis or vagina
  • prostate
  • ureters
  • urethra

The muscles and nerves must work together to hold and release urine from the bladder.

Urinary problems, such as poor bladder control or retention of urine, are caused by damage to the nerves that carry signals to the muscles.

8. Childbirth

Smooth muscles in the uterus expand and contract during childbirth. These movements push the baby through the vagina. Also, the pelvic floor muscles help to guide the baby’s head down the birth canal.

9. Vision

Six skeletal muscles around the eye control its movements. These muscles work quickly and precisely, and allow the eye to:

  • maintain a stable image
  • scan the surrounding area
  • track moving objects

If someone experiences damage to their eye muscles, it can impair their vision.

10. Organ protection

Muscles in the torso protect the internal organs at the front, sides, and back of the body. The bones of the spine and the ribs provide further protection.

Muscles also protect the bones and organs by absorbing shock and reducing friction in the joints.

11. Temperature regulation

Maintaining normal body temperature is an important function of the muscular system. Almost 85 percent of the heat a person generates in their body comes from contracting muscles.

When body heat falls below optimal levels, the skeletal muscles increase their activity to make heat. Shivering is one example of this mechanism. Muscles in the blood vessels also contract to maintain body heat.

Body temperature can be brought back within normal range through the relaxation of smooth muscle in the blood vessels. This action increases blood flow and releases excess heat through the skin.

Five fun facts about the muscular system

  1. Muscles make up approximately 40 percent of total weight.
  2. The heart is the hardest-working muscle in the body. It pumps 5 quarts of blood per minute and 2,000 gallons daily.
  3. The gluteus maximus is the body’s largest muscle. It is in the buttocks and helps humans maintain an upright posture.
  4. The ear contains the smallest muscles in the body alongside the smallest bones. These muscles hold the inner ear together and are connected to the eardrum.
  5. A muscle called the masseter in the jaw is the strongest muscle by weight. It allows the teeth to close with a force of up to 55 pounds on the incisors or 200 pounds on the molars.

New Mexico Orthopaedics is a multi-disciplinary orthopedic clinic located in Albuquerque New Mexico. We have multiple physical therapy clinics located throughout the Albuquerque metro area.

New Mexico Orthopaedics offers a full spectrum of services related to orthopedic care and our expertise ranges from acute conditions ó such as sports injuries and fractures ó to prolonged, chronic care diagnoses, including total joint replacement and spinal disorders.

Because our team of highly-trained physicians specialize in various aspects of the musculoskeletal system, our practice has the capacity to treat any orthopedic condition, and offer related support services, such as physical therapy, WorkLink and much more.

If you need orthopedic care in Albuquerque New Mexico contact New Mexico Orthopaedics at 505-724-4300.

Источник: https://www.nmortho.com/what-are-the-main-functions-of-the-muscular-system/

Skeletal System


The study of bone: "Osteology"

This system in adulthood has 206 bones but at birth 270

The skeleton can be broken into 2 categories:

  • Axial: form the axis of the body and protect major organs
  • Appendicular: upper and lower extremities and bony girdles


Bone is living tissue that provides several key functions. Some are involved in the structure of the human body and some play a role in the function of vital process of life.

Support: rigid framework for soft tissues and organs


  • Skull and Vertebral column: Central Nervous System
  • Ribs: Heart and lungs
  • Pelvic Cavity: The organs found inside the pelvis area (reproductive and digestive organs known as the "pelvic viscera")

Body movement:

Anchoring attachments for most skeletal muscles


  • Red marrow in adults produce white, red blood cells and platelets
  • In infants this is done by spleen and liver
  • Estimated average of 1 million bloods cells produced per second

Mineral storage:

  • Ca (95%), P (90%) Mg, Na, K,
  • Heavy Metals: Pb, U, Sr


Long Bones:

  • Longer than they are wide
  • Function as a lever
  • Most bones of the legs and arms

Short Bones:

  • Cube shaped
  • Found in confined spaces where they transfer forces
  • Examples: Wrists and ankles

Flat Bones:

  • Broad dense surfaces for muscle attachments
  • For protection of underlying organs (cranium, ribs, shoulder girdle)
  • Irregular Bones:

    • Various shapes and many surfaces for muscle attachments
    • Ex. Vertebrae, Pelvis

    Sesamoid Bones

    • is a bone embedded within a tendon or a muscle.
    • Ex. Knee cap (patella) and Adam’s apple in neck (hyoid bone)

    Growth and Maturation

    Bone is a living tissue. It is constantly growing, recycling, and maturing through our lives. There are 3 specific bone cells, each having their own role in the growth and maturation of our skeletal system.


    mature bone cells


    bone-building cells


    bone-destroying cells (growth, healing)

    Need To Know Examples

    These are the bones you are responsible for:

    • carpals
    • Clavicle
    • Cranium
    • Femur
    • Humerus
    • Mandible
    • Metacarpals
    • Metatarsals
    • Patella
    • Pelvis
    • Phalanges
    • Radius
    • Rib cage
    • Sternum
    • Tarsals
    • Tibia
    • Ulna
    • Vertebrae

    Muscular System - Fact

    There are approximately 650 skeletal muscles in the human body.

    A muscle can only “act” when it receives signals from the nervous system.

    The release of the signal to control a muscle can be both voluntary (controlled) or involuntary (not controlled) from the nervous system.

    Each muscle attaches to bone at both ends. One end called the origin which is often the proximal location, and the other attachment is the insertion, which is commonly the distal end of the muscle.

    In a muscle contraction, the insertion always moves towards the origin.

    Muscles make up 40% of your total body weight.

    Muscles cannot push, they must always pull.

    Muscular System - Function

    The function of muscle is to attach to bone and when activated contract, thus bringing the bones attached at each end of the muscle together. This is known as a muscular contraction.

    There are three types of muscle contraction, as shown in the diagram (top to bottom):

    • Concentric contraction (shortening)
    • Eccentric contraction (lengthening)
    • Isometric contraction (static)

    Muscular System - Types

    There are 3 types of Muscle Tissue:

    Smooth Muscle

    • long and spindle shaped
    • found in walls of organs with hollow cavities
    • serve to propel material along length of those cavities
    • examples: urinary, respiratory, reproductive ducts, blood vessels, gastrointestinal tract
    • action generally characterized by slow, sustained, rhythmic contractions (like peristalsis)
    • INVOLUNTARY (work without conscious control)

    Cardiac Muscle

    • heart muscle
    • contracts spontaneously, therefore it’s INVOLUNTARY
    • More organized than smooth muscle
    • “pseudo-striated”
    • Avg. Heart rate is approx. 65 bpm

    Skeletal Muscle

    • also called striated
    • long, cylindrical and striped in appearance
    • make up form of body; usually attach to bone via tendons and cross a joint
    • muscular contraction moves one bone at the joint to produce movement
    • characterized by rapid, short- term contraction of great strength
    • under VOLUNTARY control

    Muscular System - Growth and Maturation

    Muscle can either grow or shrink depending on the load that is placed on the muscle.

    Muscle hypertrophy involves an increase in size of skeletal muscle through a growth in size of its cells as a result in an increased demand or load placed on the muscle.

    Muscle atrophy is defined as a decrease in the mass of the muscle which can be a partial or complete wasting away of muscle, This is most commonly experienced when persons suffer some type of loss of demand on the muscle such as an injury, disease or even a lock of gravity (space).

    Reasons for Growth:

    • Overall health
    • Rehabilitation
    • Training
    • Sport related performance

    Muscular System - Growth and Maturation

    You are responsible for researching what movement each muscle performs for each of the following muscles.

    • Abdominals
    • Latissimus Dorsi
    • Pectorals
    • Obliques
    • Sternocleidomastoid
    • Trapezius
    • Deltoids
    • Triceps
    • Biceps Brachii
    • Forearms
    • Gluteals
    • Hamstrings
    • Gastrocnemius
    • Quadriceps
    • Sartorius
    • Tibialis Anterior

    Articular System - Fact

    The articular system deals with joints of the body and the surrounding tissues.

    Components of articular system:

    Ligaments: band of fibrous tissue that connects 2 bones and provides the attachment for the cartilage, fascia and muscle.

    Tendons: connects the muscle to the bone

    Cartilage: fibrous tissue that covers the ends of bones, can withstand great amounts of pressure and tension and provides a cushion for the joint

    Joints are points of contact between 2 or more bones.

    Joints can be classified into 3 types:

    • Cartilaginous joints which are slightly moveable. (ex. Intervertebral disks)
    • Fibrous Joints which are not moveable. (Ex. Sutures of the skull)
    • Synovial joints which are totally moveable and are often sites of movement related injuries. (Ex. Knee, shoulder, etc.)

    Fibrous Joints:

    • Have a thin layer of fibrous periosteum between the 2 bones.

    Cartilagenous Joints:

    • Has either fibrocartilage or hyaline (articular) cartilage between the 2 bones.

    Synovial Joints: All synovial joints contain these 7 common components:

    • Synovial fluid for joint lubrication & nutrition
    • Articular cartilage to spread out and absorb forces
    • Articular capsule to surround and protect the joint
    • Synovial membrane to produce the fluid for the joint
    • Capsular ligaments to limit excessive joint motion
    • Blood vessels to provide nutrients, permit healing to occur
    • Sensory nerves transmit pain and awareness of position (proprioception)

    Articular System - Function

    The function of the articular system is:

    1. To allow motion of the musculoskeletal system.
    2. To bear weight.
    3. To hold the skeleton together.

    Articular System - Types

    When we think of joints in the human body, we think specifically of synovial joints. There are 6 different types and each one has a specific movement that makes them ideal for their location.

    Gliding joints

    • Articular surfaces are essentially flat
    • Allow only slipping or gliding movements
    • Only examples of nonaxial joint
    • E.g. intercarpal/intertarsal joints, vertebral articular processes

    Hinge joints

    • Cylindrical projections of one bone fits into a trough-shaped surface on another
    • Motion is along a single plane (like a mechanical hinge)
    • Uniaxial joints permit flexion and extension only
    • Examples: elbow and interphalangeal joints

    Pivot Joints

    • Rounded end of one bone protrudes into a "sleeve" or ring, composed of bone (and possibly ligaments) of another
    • uniaxial rotation of one bone around its own long axis
    • Examples: “No” motion of the head via joint between the the 2nd and 3rd vertebra

    Condyloid or Ellipsoidal Joints

    • Oval articular surface of one bone fits into a complementary depression in another
    • Both articular surfaces are oval Biaxial joints permit all angular motions
    • Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

    Saddle Joints

    • Similar to condyloid joints but allow greater movement
    • Each articular surface has both a concave and a convex surface
    • Example: carpometacarpal joint of the thumb

    Ball-and-Socket Joints

    • A spherical or hemispherical head of one bone articulates with a cuplike socket of another
    • Multiaxial joints permit the most freely moving synovial joints
    • Examples: shoulder and hip joints


    • the more stable a joint, the less mobile the joint
    • Ball and socket joint is highly mobile, moving in 3 planes but unstable
    • Ellipsoidal/ Condyloid, Saddle: balance of stability and mobility, moving in 2 planes
    • Hinge joint and pivot joint: highly stable but move only in 1 plane so less mobile

    Articular System - Growth and Maturation

    The older we get the cartilage around the end of our bones and joints, naturally deteriorates. The smooth tissue that cushions joints and helps them move more easily disappears with age. Basically, wearing out the body’s natural shock absorbers.

    In addition, we lose muscle tone and bone strength the older we get thus putting more stress on areas of articulation (joints).

    Articular System - Need to Know Examples

    These are the joints in the body that you need to know and what type of joint they are.

    • Skull
    • Shoulder
    • Intervertebral discs
    • Elbow
    • Wrist
    • Thumb
    • Metacarpophalangeal (knuckle)
    • Ankle
    Источник: https://lah.elearningontario.ca/CMS/public/exported_courses/PSK4U/exported/PSK4UU3/PSK4UU3A3/_ld7.html

    The Human Skeletal System

    The human skeletal system is not quite as simple as the popular children's song suggests. The "head bone" (actually made up of 22 separate bones) is not connected to the "neck bone," but rather to a series of small bones that go all the way down the back. And the "toe bone" is actually made up of several bones that connect to another set of bones that provide structure for the foot. In total, the human skeleton consists of a whopping 206 bones.

    In addition to all those bones, the human skeletal system includes a network of tendons, ligaments and cartilage that connect the bones together. The skeletal system provides the structural support for the human body and protects our organs. Our bones also serve several other vital functions, including producing blood cells and storing and releasing fats and minerals, according to the National Center for Biotechnology Information (NCBI).

    Development and structure of the skeleton

    Infants are born with about 300 separate bones, according to Nemours, a nonprofit children's health provider. As a child grows, some of those bones fuse together until growth stops, typically by the age of 25, leaving the skeleton with 206 bones. 

    Our bones are separated into two categories based on the purpose and location of the bones: The axial skeleton and the appendicular skeleton, according to the SEER program of the National Cancer Institute.

    The axial skeleton contains 80 bones, including the skull, spine and rib cage. It forms the central structure of the skeleton, with the function of protecting the brain, spinal cord, heart and lungs.

    The remaining 126 bones make up the appendicular skeleton; they include the arms, legs, shoulder girdle and pelvic girdle. The lower portion of the appendicular skeleton protects the major organs associated with digestion and reproduction and provides stability when a person is walking or running. The upper portion allows for a greater range of motion when lifting and carrying objects.

    Bones are further classified by their shape: long, short, flat, irregular or sesamoid, according to SEER. 

    • Long bones are found in the arms, legs, fingers and toes. These bones are longer than they are wide and are cylindrical. They move when the muscles around them contract, and they are the most mobile parts of the skeleton.
    • Short bones are found in the wrists and ankles and are about equal in their length, width and thickness. 
    • Flat bones make up the skull, shoulder blades, sternum and ribs. These curved, thin bones protect internal organs and provide an anchor for muscles.
    • Irregular bones are those in the spinal cord and face, which, because of their unique dimension, don't fit in any of the other shape categories.
    • Sesamoid bones are found in the hands, wrists, feet, ears and knees. These small, round bones are embedded in tendons and protect them from the great pressure and force they encounter.

    There are some variations between male and female skeletons. For example, the female pelvis is typically more broad, thin, and round than the male pelvis, according to the National Museum of Natural History. [Image Gallery: The BioDigital Human]

    Three main types of material make up every bone in your body: compact bone, spongy bone and bone marrow, according to the School of Life Sciences at Arizona State University.

    Approximately 80% of every bone is compact bone, which is the hardest and strongest type of bone and is what allows the body to support its weight. Compact bone makes up the outer layers of the bone and protects the inner parts of the bones where many vital functions occur, such as bone marrow production. Compact bone consists primarily of cells called osteocytes. Microscopic passages in between the cells to allow nerves and blood vessels to pass through.

    About 20% of each bone is spongy bone, which is filled with large holes and passages. Most often found toward the ends of individual bones, the spongy bone material is filled with bone marrow, nerves and blood vessels. 

    Two types of bone marrow fill the pores in spongy bone. Approximately half is red bone marrow, which is found mainly within flat bones such as shoulder blades and ribs. This is where all red and white blood cells and platelets (cells that help a cut stop bleeding) are made. Infant's bones contain all red bone marrow to produce enough blood cells to keep up with the youngsters' growth. 

    The other half of marrow is yellow bone marrow, which is found in long bones, such as thigh bones, and consists primarily of fat. Blood vessels run through both types of bone marrow to deliver nutrients and remove waste from the bones.

    There are four main types of cells within bones: Osteoblasts, osteocytes, osteoclasts and lining cells, according to the NCBI.

    Osteoblasts are cells that create new or repair existing bone material as the bones grow or break. The cells create a flexible material called osteoid and then fortify it with minerals to harden and strengthen it. When osteoblasts successfully finish their job, they retire to become osteocytes or lining cells.

    Osteocytes, found in the compact bone, are responsible for exchanging minerals and communicating with other cells in the vicinity. They are formed from old osteoblasts that have gotten stuck in the center of bones.

    Osteoclasts break down existing bone material and reabsorb it. These cells often work with osteoblasts to heal and reshape bone after a break (the osteoclasts break down the extra callus formed by the healing process) to make room for new blood vessels and nerves and to make bones thicker and stronger.

    Lining cells are flat bone cells that completely cover the outside surface of bones. Their primary function is controlling the movement of minerals, cells and other materials into and out of the bones.

    Diseases of the skeletal system

    As with any part of the human body, bones are susceptible to injury and disease.

    Some of the most common diseases that can affect the skeletal system include:

    • Osteoporosis is a disease that causes the density and strength of bones to decrease because bone loss occurs faster than bone growth. It can be caused by genetics or unhealthy lifestyle habits (such as lack of calcium or vitamin D, and heavy smoking or drinking with little exercise).
    • Leukemia is a type of cancer that starts in the bone marrow and the lymphatic system, according to the Mayo Clinic. Several types of leukemia affect various blood cells and other systems of the body.
    • Osteoarthritis is a disease that causes the breakdown of the cartilage that protects the ends of bones in joints. This lack of cartilage leads to bone-on-bone rubbing, which can cause significant pain, damage to the bones and connective tissues, inflammation of the surrounding tissue and restricted motion, according to the Mayo Clinic

    Additional resources:

    This article was updated on Oct. 18, 2021, by Live Science contributor Ben Biggs. 

    This article is for informational purposes only, and is not meant to offer medical advice. 

    Kim Ann Zimmermann is a contributor to Live Science. She holds a bachelor’s degree in communications from Glassboro State College.
    Источник: https://www.livescience.com/22537-skeletal-system.html
    SEER Training, training.seer.cancer.gov/anatomy/skeletal/. 
    Источник: https://www.thoughtco.com/skeletal-system-373584