Mucles topic 1

Topic 8

Muscular system 1

By Group 3

Diego, Damián, Darío And Enrique

Index

1. What is a muscle

2. Type of muscle acording to the type of fiber that constitute them

3. Type of muscle acording to their shape

4. Mimic muscles

5. Muscle contraction

What is a mucle?

What is a muscle?

Muscles are structures or tissues existing in humans that have the ability to generate movement by contracting and relaxing.​ The tissue that forms muscle is called muscle tissue and is made up of specialized cells called myocytes.

Type of muscle acording to the type of fiber

There are three types of muscles fibers:

Skeletal or striated muscleThis type forms the muscles that are attached to bones, such as those involved in locomotion. These muscles have voluntary contraction, which can be very fast, and they suffer from muscle fatigue.

The term striated refers to the fact that, when viewed under a microscope, we can observe regular alternation.

Cardiac muscleThese forms costitute the main tissues of the wall of the heart muscle or myocardium and these tissues are responsible for bombarding blood through the circulatory system through contraction.it has a striated structure, contracts involuntarily and does not suffer muscle fatigue.

Smooth muscle Consists of thick and thin filaments. This makes up the muscles of the internal organs, or in other words, in the walls of the gastrointestinal tract, airways, the walls of arteries and veins, ureters, urinary bladder, oviducts, uterus, etc.

Type of muscle acording to their shape

Different shapes of muscles

TRIANGULAR SHAPE Triangle-shaped. They cover a wide area and converge into a central tendon.

One example is the pectoralis major muscle.

PARALLELIn this type of muscles, the fascicles are located in a parallel arrangement, along the longitudinal axis of the muscle. There are three types of parallel muscles:

1. Elongated muscles

2. Fusiform muscles

2. Flat muscles

FusiformThey are ovoid in shape with a wider central portion and thinner ends, like the biceps brachii muscle.

ElongatedThey are located on the extremities and allow a great range of movement. For example, the sartorius muscle.

FlatThey are fan-shaped, that is, their fibers emerge from a narrow base, ending with one end much wider than the other. One example is the pectoralis-major muscle.

ORBICULARThey are muscles that form a ring-like structure around an opening or surround an orifice. For example, the orbicular muscles in the eyelids.

PENIFORM MUSCLESIn this type of muscle, the fascicles are short and insert obliquely to a central tendon that runs along the muscle. There are 3 types:

1. UnipeniformThe fascicle inserts on only one side of the tendon, like the extensor digitorum longus muscle.

2. BipeniformThe fascicles insert into the tendon on opposite sides. An example is the rectus femoris muscle in the thigh.

3. MultipeniformIn this type of muscle, all the tips of the muscle are inserted into a big tendon. An example is the deltoid muscle.

Mimic muscles

Orbicular of the lipsThey open and close the mouth

Orbicular of the eyelidThey open and close the eyes

NasalsThey wrinkle the nose

RisoriesThey stretch the lips

FrontalThey raises the eyebrows and wrinkles the forehead

Frontal

BuccinatorsThey puff out their cheeks

muscle contraction

THE MUSCLE PERFORMS TWO MOVEMENTS

MUSCLE CONTRACTION MUSCLE RELAXATION

MOVEMENTS AROUND A JOINT ARE ARCHIEVED BY THE JOINT ACTION OF TWO MUSCLES:

IN CONTRACTION IN RELAXATION

Antagonist muscle: Biceps Agonist muscle: Triceps

Antagonist muscle: TricepsAgonist muscle: Biceps

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