Muscles

Voluntary muscles.

They contract at will to make movements of the bone possible.
They cover the skeleton.
They also cause movements of overlying tissues, as in the face.

They cause movements of overlying tissues, as in the face, where they create the expression of feelings, as shown by smiles and frowns.

About 42 percent

36 percent

There are three types of muscles.

Striated muscle
Smooth, or unstriated muscle
Heart muscle

Striated muscle reveals patterns when viewed under a microscope. All voluntary muscles are striated.

Smooth, or unstriated, muscle is found in the walls of blood vessels, the alimentary tract and the ducts of glands.

Heart muscle is a specialized type of striated muscle, contracting automatically at a rate regulated by its nerve supply.

A muscle fiber can vary in size from fractions of an inch (several millimetres) to over one foot (30 centimeters).

Skeletal muscle consists of a tough fibrous sheath called fascia, which is usually connected at one or both ends to bundles of white fibrous tissue – a tendon.

It is usually connected at one or both ends to bundles of white fibrous tissue – a tendon.

Tendons anchor muscles to bones and joints

In order to move bones and joints, a muscle must be fixed at its origin, which is nearer the inner aspect of the body and the upper part of a limb.

The other end (the insertion) is attached to a point away from the center of the body and toward the end of a limb.

Some attachments are complex fibrous structures.

When a muscle contracts, the origin remains stationary and the insertion moves.

Yes. Muscles must cross the joint that they move; some pass over more than one joint, for example, the biceps, which passes over the shoulder and the elbow.

When a muscle contracts, it shortens and pulls, but cannot push.

As a contraction passes away, the muscle becomes soft and longer.

However, movement cannot take place unless other muscles, having the opposite action, relax-these paired muscles are called antagonists.

Antagonists

It shortens and pulls, but cannot push.
As a contraction passes away, the muscle becomes soft and longer

From glycogen, the chief carbohydrate, the chief carbohydrate storage material in animals.

Glycogen

Muscle and liver in animals

Glycogen is broken down into carbon dioxide and water with the release of energy through a process of oxidation, in which oxygen is consumed.

During leisurely activity, enough oxygen is available, but during violent exercise, there is often not enough oxygen , and lactic acid is produced instead of carbon dioxide.

During violet exercise, when there is not enough oxygen, lactic acid is produced in stead of carbon dioxide

It gives rise to cramps and fatigue.

(forehead)

(moves shoulder and upper arm)

(bends arm)

(stomach)

(bends and turns leg)

Skeletal muscles move and support the skeleton.

A skeletal muscle links two bones across its connecting joint.

50 percent

640

Superficial muscles.

Deep muscles

In the hollow parts of the body.

Stomach
Intestines
Blood vessels
Bladder

Smooth muscles are arranged in layers with the fibers in each layer running in a different direction

This means that you cannot consciously control this muscle.

These muscles are under the control of autonomic nervous system.

Your strongest muscles are the masseters on each side of your mouth.

They allow you to bite into things with a force of 73kg (160lb).

Masseters

Cardiac muscles cells are striped, like skeletal muscle cells.

Cardiac muscles contract automatically to squeeze the walls of the heart inward

The heart beats nonstop about 100,000 times each day.

It can do this because of the cardiac muscles.

Most of your heart is made of cardiac muscle.

The cardiac muscle never gets tired and never stops working until you die.

A good example of a pair of muscles working together can be seen in the human arm.

Biceps muscle

Triceps muscle.

Antagonistic action of muscles because they are always working in opposite ways.

Contraction of the biceps muscle bends the arm.

Contraction of the triceps muscles straightens the arm.

There are muscles in the legs which work the same way to bend the knees, ankles and toes.

By contracting

Bending and straightening the arm

To bend the arm requires one set of muscles – the biceps –

To contract, while another set – the triceps – relaxes.

Into extensors (muscles that straighten a limb) and

flexors (muscles that bend a limb).

Muscles that straigthten a limb

Muscles that bend a limb

Extensors

Flexors

Voluntary muscle or a skeletal muscle

It is sometimes called striped muscle because this is what it looks like through a microscope.

It is also called voluntary muscle because this is the muscle which you have direct control over when you want to make a movement

You may also be told that it is called Skeletal muscle, this is because it is attached to the skeleton.

On your legs arms etc., you have direct control over these muscles and can make almost any movements which you want to.

These muscles are also found in your face and jaws.

When you smile or frown and when you talk, eat or drink.

Antagonistic muscles

Involuntary muscle

Because you cannot see any stripes when you look at it through the microscope;

Because you cannot make it contract and relax through conscious control.

Automatically

Intestines
Iris of your eye.

Sometimes the muscles squeeze the salivary gland so strongly that it hurts.

When you take a mouthful of food, smooth muscles in your salivary gland squeeze the gland so that saliva squirts into your mouth.

In pairs.

When the circular muscles contract they make the intestines longer (and thinner) and when the longitudinal muscles contract they make the intestines shorter (and fatter).

These muscles move food along the guts (peristalsis) and help to mix food with your digestive juices.

Cardiac muscle

The muscle of your heart is also striped but it is involuntary.

It is called cardiac muscle:

"of the heart".

How fast the blood is pumped around your body

Adrenaline

Vagus nerve

When you are sitting or lying down.

No, they work in pairs

This is because they can contract and relax but cannot push or stretch themselves

Myocardium (my-uh-kar-dee-um).

The thick muscles of the heart contract to pump blood out and then relax to let blood back in after it has circulated through the body.

As the pacemaker of the heart, because it controls the heartbeat.

Striated (stry-ay-tud) muscle

Because the light and dark parts of the muscle fibers make them look striped (striated is a fancy word meaning striped).

True

It means you can control what they do.

Musculoskeletal system
(mus-kyuh-low-skel-uh-tul)

With the help of tendons

Tendons are cords made of tough tissue.

Tendons work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Some of your biggest and most powerful muscles are in your back, near your spine. These muscles help keep you upright and standing tall.

They also give your body the power it needs to lift and push things.

Muscles in your neck and the top part of your back aren't as large, These muscles also hold your head high.

In each of your shoulders

It helps you move your shoulders every which way — from swinging a softball bat to shrugging your shoulders when you're not sure of an answer.

On each side of your upper chest.

Rectus abdominus muscles ( rek-tus ab-dahm-uh-nus), or

abdominals (say: ab-dahm-uh-nulz).

They're often called abs for short.

When you make a muscle in your arm, you tense your biceps muscle.

When you contract your biceps muscle, you can actually see it push up under your skin.

Muscles on the front of your thighs.

Gluteus maximus

They create movement when one (the prime mover) contracts and the other (the antagonist) relaxes.

Quadriceps and hamstrings in the leg

Biceps and triceps in the arm

Acids

Alveoila

Biceps

Bile

Quadriceps and hamstrings in the leg

Biceps and triceps in the arm

Acids

Alveoila

Biceps

Bile

Bladder

Bone marrow

Bronchi

Cartilage

Capillaries

Carbon dioxide

Cardiac

Carpal

Condense

Corneas

Digestion

Diaphragm

Enzyme

Esophagus

Exhale

Hepatic

Humerus

Inhale

Kidney

Liter

Larynx

Lungs

Mandible

Metatarsus

Membrane

Metacarpus

Nasal cavity

Nephrons

Organ

Oxygen

Pancreas

Pancreatic juice

Peristalsis

Pharynx

Phalange

Process

Radius

Respiration

Rib cage

Ribs

Saliva

Starch

Tarsal

Tendons

Trachea

Ulna

Ureter

Vertebrae

Villi