emmanuelm23

[emmanuelm23]

Up to basketball 🏀, we should understand the basics of this sport; namely the set shot - the skill of shooting the balll in the basket. Here is a proper stance ,execution and follow through of a set shot performed by myself in a gymnasium.

Things to remember when performing the set shot in basketball 🏀

1. Have a proper stance , our feet should be facing the ring and be at shoulder width open.

2. With the dominant hand hold the ball still. It should be on the top of our head (not touching our forehead)

3. The non-dominant hand will hold the ball by the side to give direct it to the ring.

4.Executing the shot, a fluid movement should come from the knee, pass through the hip to finish with the arm force.

5. The last part is to apply a reverse hand when releasing the ball in order for a back spin to occur.

6.This backspin will create and arc going up the ring to enter it clearly.

7.RESTART

[emmanuelm23]

Most muscles are made up of two kinds of muscle fibers that help you move your body:

slow-twitch muscle fibers, which move more slowly but help to keep you moving longer

fast-twitch muscle fibers, which help you move faster, but for shorter periods.

“Twitch” refers to the contraction, or how quickly and often the muscle moves.

FAST TWITCH

Fast twitch muscles support short, quick bursts of energy, such as sprinting or powerlifting. You can see how they’re meant to function when you compare their design and structure to slow twitch muscles.

Fast twitch muscles have very few blood vessels and mitochondria (unlike slow twitch muscles) because they don’t need to fuel quick, intense activities.

This is because fast twitch muscles are anaerobic. They use sources of energy that are already present inside your body, such as glucose, to make adenosine triphosphate (ATP).

Here’s a breakdown of the different types of fast twitch muscles.

Type IIa

Type IIa is the first type of fast twitch muscle. (Keep in mind that Type I muscles are slow twitch. More on that later).

They’re known as oxidative-glycolytic muscles because they can use oxygen and glucose for energy.

These fast twitch muscles have a higher number of mitochondria than the other type, Type IIb. This makes them similar to slow twitch muscles in their ability to use oxygen along with glucose and fat to burn for energy.

And like slow twitch muscles, Type IIa fast twitch muscles are not easily exhausted and can recover from a short, intense workout relatively quickly.

Type IIb

Type IIb is the second type of fast twitch muscle. They’re known as nonoxidative muscles because they don’t use any oxygen for energy. Instead, they rely on glucose to produce the energy needed for activity.

Type IIb muscles also have a much lower number of mitochondria because they don’t need them to produce energy from oxygen like Type I and Type IIa muscles do.

They’re also much larger around than other muscles and become worn out much faster than the other types of muscles despite their capacity for feats of strength.

Fast twitch muscles are optimized for short, intense activities, such as:

sprinting

powerlifting

jumping

strength training

agility training

high-intensity cycling

high-intensity interval training (HIIT)

SLOW TWITCH

Most of the muscles in your body have more than one kind of muscle fiber. But some muscles have more slow-twitch fibers because they have to do the same job for a long time.

For example, the muscles in the back of your lower legs and the muscles in your back are mostly made up of slow-twitch fibers. This is because they have to help you stand and hold your posture for long periods of time.

Fast-twitch fibers wouldn’t be able to do this because they can’t keep working for that long. Muscles that need speed rather than endurance will have more fast-twitch fibers. For example, the muscles in your eyelids that help you blink are all fast-twitch fibers.

Your slow-twitch muscle fibers are working hard whenever you’re doing an activity or exercise that needs muscles to work — or even stay still — for a long time. These include:

sitting up

standing

walking

slow jog

running a marathon

biking

swimming laps

rowing

many yoga positions

some pilates exercises

[emmanuelm23]

PAIR OF MUSCLES

There are common muscles that work together.

One is called agonist and the other antagonist .

AGONIST

Agonist muscles are also called prime movers since they produce most of the force, and control of an action. Agonists cause a movement to occur through their own activation.For example, the triceps brachii contracts, producing a shortening (concentric) contraction, during the up phase of a push-up (elbow extension). During the down phase of a push-up, the same triceps brachii actively controls elbow flexion while producing a lengthening (eccentric) contraction. It is still the agonist, because while resisting gravity during relaxing, the triceps brachii continues to be the prime mover, or controller, of the joint action.

ANTAGONIST

Antagonist muscles are simply the muscles that produce an opposing joint torque to the agonist muscles.This torque can aid in controlling a motion. The opposing torque can slow movement down - especially in the case of a ballistic movement. For example, during a very rapid (ballistic) discrete movement of the elbow, such as throwing a dart, the triceps muscles will be activated very briefly and strongly (in a "burst") to rapidly accelerate the extension movement at the elbow, followed almost immediately by a "burst" of activation to the elbow flexor muscles that decelerates the elbow movement to arrive at a quick stop.

Examples of pair muscle: 💪🏼

Agonist. Antagonist

1.Pectorals (pecs) Latissimus dorsi (lats)

2.Anterior deltoids. Posterior deltoids ( back shoulder)

3.Trapezius (traps) Deltoid (delts)

4.Abdominals (abs). Spinal erectors ( lower back)

5.Left external obliques Right exetrnal obliques

6.Quadriceps ( quads) Harmstrings ( hams)

7.Shins Calves

8.Biceps Triceps

9.Forearms flexors Forearms extensors

Antagonistic muscle pairs in action

In the preparation phase, when a footballer prepares to kick a football, their hamstrings contract to flex the knee while the quadriceps lengthens to allow the movement. The hamstrings are the agonist and the quadriceps are the antagonist.

In the contact and recovery phase, the quadriceps contract to extend the knee while the hamstrings lengthen to allow the movement. The quadriceps are the agonist and the hamstrings are now the antagonist.

[emmanuelm23]

FUNCTIONS OF MUSCLES

The muscular system is like a machine that converts chemical energy from food into mechanical energy.

There are 4 known basic functions of muscles :

1) PRIME MOVERS

Skeletal muscles pull on the bones causing movements at the joints.

Skeletal muscles pull on the soft tissues of the face causing facial expressions.

Movement caused by the respiratory muscles enables breathing.

2) SYNERGIST

The synergist in a movement is the muscle(s) that stabilises a joint around which movement is occurring, which in turn helps the agonist function effectively. Synergist muscles also help to create the movement. In the bicep curl the synergist muscles are the brachioradialis and brachialis which assist the biceps to create the movement and stabilise the elbow joint.

3) STABILIZERS

First off, every superficial muscle in your body can act as a stabilizer muscle. It all depends on what exercise or movement you are performing. Certain muscles take on the role of stabilizing during specific exercises, rather than always existing in that persistent state…

Stabilizer muscles are tasked with stabilizing the body and extremities during multiplanar movements, while primary movers are the muscles doing most of the work.

Stabilizer muscles aren’t directly involved in moving the load, they are working to keep certain body parts stable and steady so the primary movers can perform the exercise efficiently, effectively, and safely.

SHOULDER STABILIZER COMPLEX:

The rotator cuff is a group of four muscles that surround the shoulder joint. These rotator cuff muscles help stabilize the shoulder. The muscles of the rotator cuff are supraspinatus, subscapularis, infraspinatus, and teres minor. Their function is crucial to maintaining optimal function and biomechanics of the shoulder joint.

HIP STABILIZER COMPLEX :

The hip stabilizer complex is made up of multiple muscles, but the main one is the gluteus medius. This is the muscle of hip joint that maintains proper biomechanic function of the lower body when walking or running, as to prevent injuries at the ankle, knee and hip. If you have weak hip stabilization, it can lead to poor alignment of the pelvis and cause compensation from other muscles which then creates muscle imbalance.

TRUNK STABILIZER COMPLEX:

The major muscles used for core stability are the pelvic floor muscles, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, and erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm.

4) ANTAGONISTS

Opposite of agonists

➢ Decelerate body segments to control motion and stabilises joints

➢ Can be both productive and counter productive

➢ Restricts desired movements when over active

➢ More prone to injury when underactive

➢ Balance between agonist and antagonist promotes health and good performance( e.g for flexibility training)

[emmanuelm23]

Skeletal muscles are the major portion of the human body. Cyclindrical; several nuclei; appear striped( arrangement of the contracting protein within the cells).It is supplied with motor nerves for movement.It also produces heat for maintaining body temperature constant.It is composed of ;Water-75% ,Solid-25%,Proteins- 20%,actin; 50%myosin,Fats-0.2%,Carbohydrates-1.0%; Glycogen-0.5-1%; Hexose phosphate- 0.05%,Inorganic salts- 1.0-1.5%.

[emmanuelm23]

SKELETAL MUSCLES

Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system that are mostly attached by tendons to bones of the skeleton.The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers.The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres.

Skeletal muscle exhibits a distinctive banding pattern when viewed under the microscope due to the arrangement of two contractile proteins myosin, and actin – that are two of the myofilaments in the myofibrils. The myosin forms the thick filaments, and actin forms the thin filaments, and are arranged in repeating units called sarcomeres. The interaction of both proteins results in muscle contraction.

The sarcomere is attached to other organelles such as the mitochondria by intermediate filaments in the cytoskeleton. The costamere attaches the sarcomere to the sarcolemma.

Every single organelle and macromolecule of a muscle fiber is arranged to ensure that it meets desired functions. The cell membrane is called the sarcolemma with the cytoplasm known as the sarcoplasm. In the sarcoplasm are the myofibrils. The myofibrils are long protein bundles about one micrometer in diameter. Pressed against the inside of the sarcolemma are the unusual flattened myonuclei. Between the myofibrils are the mitochondria.

While the muscle fiber does not have smooth endoplasmic cisternae, it contains sarcoplasmic reticulum. The sarcoplasmic reticulum surrounds the myofibrils and holds a reserve of the calcium ions needed to cause a muscle contraction. Periodically, it has dilated end sacs known as terminal cisternae. These cross the muscle fiber from one side to the other. In between two terminal cisternae is a tubular infolding called a transverse tubule (T tubule). T tubules are the pathways for action potentials to signal the sarcoplasmic reticulum to release calcium, causing a muscle contraction. Together, two terminal cisternae and a transverse tubule form a triad.

Exercise is often recommended as a means of improving motor skills, fitness, muscle and bone strength, and joint function. Exercise has several effects upon muscles, connective tissue, bone, and the nerves that stimulate the muscles. One such effect is muscle hypertrophy, an increase in size of muscle due to an increase in the number of muscle fibers or cross-sectional area of myofibrils. Muscle changes depend on the type of exercise used.

Generally, there are two types of exercise regimes, aerobic and anaerobic. Aerobic exercise (e.g. marathons) involves activities of low intensity but long duration, during which the muscles used are below their maximal contraction strength. Aerobic activities rely on aerobic respiration (i.e. citric acid cycle and electron transport chain) for metabolic energy by consuming fat, protein, carbohydrates, and oxygen. Muscles involved in aerobic exercises contain a higher percentage of Type I (or slow-twitch) muscle fibers, which primarily contain mitochondrial and oxidation enzymes associated with aerobic respiration. On the contrary, anaerobic exercise is associated with exercise or short duration but high intensity (e.g. sprinting and weight lifting). The anaerobic activities predominately use Type II, fast-twitch, muscle fibers.Type II muscle fibers rely on glucogenesis for energy during anaerobic exercise.During anaerobic exercise, type II fibers consume little oxygen, protein and fat, produces large amounts of lactic acid and are fatigable. Many exercises are partially aerobic and anaerobic; for example, soccer and rock climbing.

The presence of lactic acid has an inhibitory effect on ATP generation within the muscle. It can even stop ATP production if the intracellular concentration becomes too high. However, endurance training mitigates the buildup of lactic acid through increased capillarization and myoglobin.This increases the ability to remove waste products, like lactic acid, out of the muscles in order to not impair muscle function. Once moved out of muscles, lactic acid can be used by other muscles or body tissues as a source of energy, or transported to the liver where it is converted back to pyruvate. In addition to increasing the level of lactic acid, strenuous exercise results in the loss of potassium ions in muscle. This may facilitate the recovery of muscle function by protecting against fatigue.

Delayed onset muscle soreness is pain or discomfort that may be felt one to three days after exercising and generally subsides two to three days later. Once thought to be caused by lactic acid build-up, a more recent theory is that it is caused by tiny tears in the muscle fibers caused by eccentric contraction, or unaccustomed training levels. Since lactic acid disperses fairly rapidly, it could not explain pain experienced days after exercise

[emmanuelm23]

VISCERAL MUSCLES

Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations.[1] It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit muscle, the whole bundle or sheet of smooth muscle cells contracts as a syncytium.

Smooth muscle is found in the walls of hollow organs, including the stomach, intestines, bladder and uterus; in the walls of passageways, such as blood, and lymph vessels, and in the tracts of the respiratory, urinary, and reproductive systems. In the eyes, the ciliary muscle, a type of smooth muscle, dilate and contract the iris and alter the shape of the lens. In the skin, smooth muscle cells such as those of the arrector pili cause hair to stand erect in response to cold temperature or fear.

Most smooth muscle is of the single-unit variety, that is, either the whole muscle contracts or the whole muscle relaxes, but there is multiunit smooth muscle in the trachea, the large elastic arteries, and the iris of the eye. Single unit smooth muscle, however, is most common and lines blood vessels (except large elastic arteries), the urinary tract, and the digestive tract.

However, the terms single- and multi-unit smooth muscle represents an oversimplification. This is due to the fact that smooth muscles for the most part are controlled and influenced by a combination of different neural elements. In addition, it has been observed that most of the time there will be some cell to cell communication and activators/ inhibitors produced locally. This leads to a somewhat coordinated response even in multiunit smooth muscle.

Smooth muscle differs from skeletal muscle and cardiac muscle in terms of structure, function, regulation of contraction, and excitation-contraction coupling. However, smooth muscle tissue tends to demonstrate greater elasticity and function within a larger length-tension curve than striated muscle. This ability to stretch and still maintain contractility is important in organs like the intestines and urinary bladder. Smooth muscle in the gastrointestinal tract is activated by a composite of three types of cells – smooth muscle cells (SMCs), interstitial cells of Cajal (ICCs), and platelet-derived growth factor receptor alpha (PDGFRα) that are electrically coupled and work together as an SIP functional syncytium

Micro anatomy

Smooth muscle cells known as myocytes, are spindle-shaped with a wide middle and tapering ends, and like striated muscle, can tense and relax. In the relaxed state, each cell is 30–200 micrometers in length.There are no myofibrils present but much of the cytoplasm is taken up by the proteins of myosin and actin which together have the capability to contract.

[emmanuelm23]

MYOCARDIUM

Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissue, with the other two being skeletal muscle and smooth muscle. It is involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix.

Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the cell's myofilaments to slide past each other in a process called excitation-contraction coupling. Diseases of the heart muscle known as cardiomyopathies are of major importance. These include ischemic conditions caused by a restricted blood supply to the muscle such as angina, and myocardial infarction.

In summary, 1)cardiac muscles are found in the heart,

2)It contracts involuntarily,

3)have different branch types,

4)has one nucleus each(mitochondrial and myoglobin),

5)has a good blood supply,

6)it’s doesn’t fatigue,

7)have faint striations,

8)is controlled by the CNS (central nervous system)

9)Pacemaker cell- so contraction need no signal from NS

10)Intercalated disc (fold and fit matching fold into each other)- permits electrical impulses to pass swiftly from cells to cells.

MYOCARDIUM FUNCTIONS

Cardiac muscle is characterized as striated muscle because microscopically, it presents a striated appearance essentially identical to that of skeletal muscle; it also shares with skeletal muscle many similar ultrastructural features. Organizationally, striated muscle fibers, whether skeletal or cardiac, are composed of sarcoplasm and a collection of organelles, much like most other cells. However, the most prominent organelles are the particularly abundant parallel myofibrils that are bundles of the contractile proteins of actin (thin) and myosin (thick) filaments. These filaments are arranged into aggregates of repeating units known as sarcomeres, within whose longitudinal boundaries the characteristic ultrastructural features of the contractile unit of striated muscle are noted.

Transmission electron micrographs in longitudinal section reveal the arrangement of myocardial contractile proteins into the now familiar elements of the sarcomere, displaying similarities and subtle differences between cardiac and skeletal muscle.Transverse tubules of cardiac muscle have diameters 3 to 5 times those of skeletal muscle, and they traverse the sarcoplasm at the level of the Z-line rather than at the A-Band/I-Band junction, as does skeletal muscle. The myocardial sarcoplasmic reticulum is not nearly as elaborate as that of skeletal muscle, and it lacks the continuous terminal cisternae that encircle myofibrils adjacent to and on either side of the transverse tubules. Instead, scattered small expansions of longitudinally oriented elements of the sarcoplasmic reticulum abut the transverse tubules in cardiac muscle. Perhaps most revealing and confirming of functional peculiarities of cardiac muscle, however, are things like the paucity of glycogen storage, the endless rows of huge mitochondria paralleling the longitudinal axis and wedged between adjacent myofibrils, and the details of intercalated disc morphology that provide logic to their function. Confirmed by electron microscopy, but also observable at the level of light microscopy, is the obviously large surface area of myocytes that is exposed to intercellular areolar connective tissue with its contained microvascular elements. This feature is the structural basis for the marvelously enhanced microvascular system of cardiac muscle.

[emmanuelm23]

PROPERTIES OF MUSCLES

Why are muscles so important? All the different types of muscles do have their functions but there are general properties of the muscles that we must know.

Conductibility- conduct action potential.

In physiology, an action potential (AP) occurs when the membrane potential of a specific cell location rapidly rises and falls: this depolarisation then causes adjacent locations to similarly depolarize.

As an action potential (nerve impulse) travels down an axon there is a change in electric polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+) gated ion channels open and close as the membrane reaches its threshold potential. Na+ channels open at the beginning of the action potential, and Na+ moves into the axon, causing depolarization. Repolarization occurs when the K+ channels open and K+ moves out of the axon, creating a change in electric polarity between the outside of the cell and the inside. The impulse travels down the axon in one direction only, to the axon terminal where it signals other neurones.

Irritability- react when stimulated.

It’s stands for the ability of an organism or a specific tissue to react to the environment. In physiology it is the state of being abnormally responsive to slight stimuli, or unduly sensitive. myotatic irritability the ability of a muscle to contract in response to stretching.

Contractibility- muscle can shorten or produce tension.

Contractibility is the ability of muscle cells to forcefully shorten. For instance, in order to flex (decrease the angle of a joint) your elbow you need to contract (shorten) the biceps brachii and other elbow flexor muscles in the anterior arm. Notice that in order to extend your elbow, the posterior arm extensor muscles need to contract. Thus, muscles can only pull, never push.

Relaxation- Return to resting properties after contraction.

Distensibility(dilated)- ability to be stretched by an outer force (muscle is not injured unless stretched beyond its physiological limits)

Elasticity- elongation, return back to its original position.

Elasticity is the ability to recoil or bounce back to the muscle's original length after being stretched.

[emmanuelm23]

MUSCULAR SYSTEM

Since we have covered and understand why the skeleton system is so important it will now help us to understand the greatest portion of the iceberg : THE MUSCULAR SYSTEM.

The muscular system is a system that includes muscle cells and muscle tissues.The human body’s muscular system consists of specific cells called muscle fibers.

There are 600 in the human body and there is no difference between the female muscular system and the male system regarding the number of body muscles. The main muscle groups are chest, back, shoulders, legs, and arms.

In biology;

The muscular system is an organ system responsible for providing strength, keeping up the balance, maintaining posture, allowing movement, and producing heat. It includes all the muscle tissues, such as the skeletal muscle tissues, smooth muscle tissues, and cardiac muscle tissues. The skeletal muscles are muscles attached to the bones and are responsible for the voluntary movements of the body.

There are three types of muscles in the body as follows:

The skeletal muscles: Skeletal muscles are attached to bones by tendons. The musculoskeletal system is the most convenient term to describe this connection. They are voluntary muscles which means that they are under the conscious control of the human. Skeletal muscles are called striated muscles because of the striations (line formations) as seen under the microscope.

Smooth muscles: Smooth muscles are mainly found in the body’s internal structures such as the digestive tract and blood vessels. Unlike skeletal muscles, smooth muscles are involuntary muscles.

Cardiac muscles: Cardiac muscles are specialized cells; they are found in the heart only. Like smooth muscles, skeletal muscles are involuntary muscles that cannot be controlled by our consciousness.

[emmanuelm23]

VERTEBRAL COLUMN

(ver-TEE-brul KAH-lum) The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone.

The human vertebral column consists of of 24 articulating(slightly movable) and 9 fused vertebrae in the sacrum and coccyx.

-Cervical spine (7 vertebrae)

-Thoracic spine (12 vertebrae)

-Lumbar spine (5 vertebrae)

-Sacrum( 5 fused vertebrae)

-Coccyx (4 fused vertebrae)

The vetebral column has 3 main functions :

• it protects the spinal cord (nerves that relay information to and from the brain)

• it support the body weight by transferring the weight downwards to the pelvis.

• the slightly moveable joints present between the bones allow movements in all directions such as bending forward and backward.

[emmanuelm23]

LIGAMENTS, TENDONS AND CARTILAGES

Ligaments, tendons and cartilages have as main purpose to bring mobility, strengthen and protect the joints. It can also increase flexibility and provide a greater range of movement.

Ligaments

Ligaments can be defined as bands of tough elastic tissue around your joints. Bones are connected together ,a supportive assist to your joints ,and limitate their range of movements.

Tendons

Tendons are strong chords compared to a rope, its connects the muscle to the bone.

When you contract (squeeze) your muscle, your tendon pulls the attached bone, causing it to move. Tendons essentially work as levers to move your bones as your muscles contract and expand.

Tendons are stiffer than muscles and have great strength. For instance, the flexor tendons in your foot can handle more than eight times your body weight.

Cartilages

Cartilages can be defined as the main type of connective tissue among the body. It has some structural and functional functions and can be found in our joints, bones, spine, lungs, ears and nose

Cartilage is a strong and smooth substance made up of “chondrocytes,” or specialized cartilage cells, that produce a matrix of collagen, proteoglycans (a special type of protein) and other non-collagenous proteins. These materials help cartilage attract water and give it its shape and specific properties.

There are three main types of cartilage: elastic cartilage, fibrocartilage and hyaline cartilage.

Elastic Cartilage

Elastic cartilage is present in the ear, nose and parts of the lungs. It is a highly flexible formulation of cartilage.

Fibrocartilage

Fibrocartilage is found in the menisci of the knee and the discs of the spine. It is far less flexible than elastic cartilage.

Hyaline Cartilage

Hyaline cartilage is found at the ends of bones – lining the joints of the body – as well as the septum of the nose and part of the breathing tube.

[emmanuelm23]

JOINTS PROBLEMS

Joint problems appear to be the common disease among youngsters and young athletes. There are main reasons why after or in between training, joints may be altered.

Joints problems can be inflammation such as pain,swelling, redness and heat. This condition of inflammation is called Arthritis. A specific form of arthritis causes the articular cartilage to wear away. This is called osteoarthritis.

The joint is affected by many diseases. They often cause joint pain and make your joints stiff, red, or swollen. They may appear to be chronicle.The act on the long term. Many of them do not recover completely .Common diseases are:

•Sjögren's Syndrome

•Arthritis

•Lupus

There are some ways to keep our joints healthy.

Getting enough physical activity is one of the most important things you can do to prevent or slow joint disorders. Activity will henceforward strengthens the muscles around your joints and helps them work better.

When you play sports, wear the right equipment to protect your joints, such as knee pads. If you already have joint problems, ask your provider what type of activities are best for you.

[emmanuelm23]

JOINTS (2nd part SYNOVIAL JOINTS)

Coming to Synovial joints, as being taught in the previous post, this type of joints are considered to be freely movable. Furthermore this type of joint tends to be the most important term in physical education. They can be detected where there is the presence of synovial fluid which in fact acts like a lubricant among the joints.

For example : The shoulder joint.

There are commonly 6 types of synovial joints, each of them have different characteristics and functions.

1. Ball and Socket joints -

The ball shaped end of one bones fits into a hollow in the other allowing greatest range of movement. In other words The distal bone is capable of motion around an indefinite number of axes, which have one common center. This enables the joint to move in many directions.

Examples of this form of articulation are found in the hip, where the round head of the femur (ball) rests in the cup-like acetabulum (socket) of the pelvis; and in the shoulder joint, where the rounded upper extremity of the humerus (ball) rests in the cup-like glenoid fossa (socket) of the shoulder blade. (The shoulder also includes a sternoclavicular joint.)

2. Hinge -

The joint can swing close and open until it is straight allowing movement of bending and straightening. Hinge joints are complex and contain many muscles and tissues. Osteoarthritis and trauma can cause pain and dysfunction in various parts of these joints.

In a hinge joint, protective cartilage covers the bones, and a thick gel called synovial fluid lubricates them, allowing them to move without rubbing against one another. All hinge joints also contain muscles, ligaments, and other tissues that stabilize the joint.

Hinge joints are more stable than ball-and-socket joints, which include the shoulder and hip joints. However, ball-and-socket joints allow a greater range of movement along more than one plane.

Examples of this joint would be the elbow, knee, finger joints (interphalangeal joints), toe joints (interphalangeal joints) and ankles (tibiotalar joint).

3. Pivot -

A ring on one bone fits over a peg on the other allowing rotation. The pivot joint is exemplified by the joint between the atlas and the axis (first and second cervical vertebrae), directly under the skull, which allows for turning of the head from side to side. Pivot joints also provide for the twisting movement of the bones of the forearm (radius and ulna) against the upper arm, a movement used, for instance, in unscrewing the lid of a jar.

Examples of this type of joint will be the neck, your wrist, and your elbow.

4. Condyloid -

(also called condylar, ellipsoidal, or bicondylar) is a bump in one bone sits in the hollow formed by another bone or bones. It can be also defined as an ovoid articular surface, or condyle that is received into an elliptical cavity. This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction.

Examples of this type of joint would be in the elbow, wrist joints, carpals of the wrist, and at the base of the index finger.

5. Gliding -

Articulating surfaces are almost flat and of similar size. The flat surfaces can glide over each other, giving a limited movement in all directions. The basic structure of synovial joints provides flexibility to gliding joints while limiting their movements in order to prevent injury.

Examples of this type of joint would be the inter-metacarpal joints and the acromioclavicular joint.

6. Saddle -

End of one bone is saddle shaped and the other bone glides on it. Movement is back and forward and from side to side. In other words is a type of synovial joint in which the opposing surfaces are reciprocally concave and convex.

Example of this type of joint would be present in the thumb, the thorax, the middle ear, and the heel.

[emmanuelm23]

JOINTS

Now that we know that we, animals, have bones in our system and understand its functions without the connection of these bones like a lego we wouldn’t be at least move or held all the bones in an exact place.

This is the role of the joints. Joints can be defined as the place where two or more bones come and connect together in the body.

Joints for instance have different types and functions namely :

- Fibrous or fixed or immovable joints

- Cartilaginous or slightly Movable joints

-Synovial or Freely movable joints

Note : SYNOVIAL JOINTS WILL BE ELABORATE IN THE NEXT POST

Fibrous or fixed or immovable joints

As the name of the joint can tell this joint is considered to have no movement around the bones.

Many of the joints in your skull are fixed. There are eight bones that fuse together to form the cranium. The joints between these bones do not allow movement, which helps protect the brain.

Cartilaginous or slightly Movable joints

Only a slight movement is possible in this type of joint. The ends of the bones concerned, are held together by strong cord called ligaments and joined by cartilage.

Movement is only possible by compression on the pad of cartilage which provides stability and_possesses shock absorption properties. An example is the joints between the vertebrae.

Slightly movable joints are called amphiarthroses. The singular form is amphiarthrosis. In this type of joint, the bones are connected by hyaline cartilage or fibrocartilage. The ribs connected to the sternum by costal cartilages are slightly movable joints connected by hyaline cartilage.

Synovial or Freely movable joints

Synovial joints allow for movement. Where the bones meet to form a synovial joint, the bones' surfaces are covered with a thin layer of strong, smooth articular cartilage. A very thin layer of slippery, viscous joint fluid, called synovial fluid, separates and lubricates the two cartilage-covered bone surfaces.

[emmanuelm23]

The bone tissue

Hence we do want to know what the bones are made of.

For sure the bones form parts of body and also about 15% of a person's total body weight. Indeed now you can trust someone when they say that their bones are heavy.

The bone is for now connective tissue at its hardest state in a human. It is made up of Collagen fibres filled with minerals mainly of calcium and salt.

Hence there are 3 types of bone tissues, including:

Compact tissue

Harder outer tissue (Subchondral tissue)

Cancellous tissue

Compact tissue and its function

Compact bone (or cortical bone) forms the hard external layer of all bones and surrounds the medullary cavity, or bone marrow.

It provides protection and strength to bones. Compact bone tissue consists of units called osteons or Haversian systems.

Therefore, compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions.

Subchondral tissue and its function

This is the smooth tissue at the ends of bones, which is covered with another type of tissue called cartilage. Cartilage is a specialized, rubbery connective tissue.

Unlike other tissues within the joint, subchondral bone is highly responsive to loading, with the ability to respond quickly to training and injury. The forces incurred by the articular cartilage are transmitted to the subchondral bone across the calcified cartilage layer, which is uniquely adapted to distribute forces and minimize shear stresses on the articular cartilage layer through an undulating association with subchondral bone.

Cancellous tissue and its function

Spongy bone or cancellous bone forms the inner layer of all bones. Spongy bone tissue does not contain osteons that constitute compact bone tissue.

It consists of trabeculae, which are lamellae that are arranged as rods or plates. Red bone marrow is found between the trabuculae. Blood vessels within this tissue deliver nutrients to osteocytes and remove waste. The red bone marrow of the femur and the interior of other large bones, such as the ilium, forms blood cells.

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Moving on,there are now different types of bone present in the skeleton system. These specific bones have for instance different sizes, quality and functions.

They are namely :

The flat bones

The long bones

The short bones

The irregular bones

The flat bone and its function

These bones are tough and can withstand hard impact. They provide a big surface for muscles attachment and protect delicate organs. Examples: the cranium protects the brain.

There are flat bones in the skull (occipital, parietal, frontal, nasal, lacrimal, and vomer), the thoracic cage (sternum and ribs), and the pelvis (ilium, ischium, and pubis). The function of flat bones is to protect internal organs such as the brain, heart, and pelvic organs. Flat bones are somewhat flattened, and can provide protection, like a shield; flat bones can also provide large areas of attachment for muscles.

The Long bones and its function

They are important for a large range of movements and produce blood cells. Examples: the femur and the humerus.

The long bones, longer than they are wide, include the femur (the longest bone in the body) as well as relatively small bones in the fingers. Long bones function to support the weight of the body and facilitate movement. Long bones are mostly located in the appendicular skeleton and include bones in the lower limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the upper limbs (the humerus, radius, ulna, metacarpals, and phalanges).

The short bones and its functions

They are small and compact. They are designed for strength, refined movements and weight bearing. Examples: the carpals of the wrist.

The Short bones are about as long as they are wide. Located in the wrist and ankle joints, short bones provide stability and some movement. The carpals in the wrist (scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid, and trapezium) and the tarsals in the ankles (calcaneus, talus, navicular, cuboid, lateral cuneiform, intermediate cuneiform, and medial cuneiform) are examples of short bones.

The irregular bones and its function

These bones have complex shapes compared to other types. They work together, act like a shock absorber and provide protection and support, Example: the vertebrae protect the spinal cord.

Irregular bones vary in shape and structure and therefore do not fit into any other category (flat, short, long, or sesamoid). They often have a fairly complex shape, which helps protect internal organs. For example, the vertebrae, irregular bones of the vertebral column, protect the spinal cord. The irregular bones of the pelvis (pubis, ilium, and ischium) protect organs in the pelvic cavity.

There is another type of bone that must be considered.

The sesamoid bone

Sesamoid bones are bones embedded in tendons. These small, round bones are commonly found in the tendons of the hands, knees, and feet. Sesamoid bones function to protect tendons from stress and wear. The patella, commonly referred to as the kneecap, is an example of a sesamoid bone.