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Colegio Gimnasio Campestre San Sebastián

NOMBRE:_______________________________________________ GRADO: 7TH GRADE

PERIODO: FOURTH AREA: SCIENCE MISS SOPHIE CORZO PÉREZ

Locomotion and bodily movements are characteristic features of the animals. The movements are effected

by various cell organelles such as cilia, flagella and organs like muscles. Muscular movements are more

powerful and energetic. The skeletal muscles apart from their role in smarter movements, provide

beautiful shapes to the body. The inner smooth muscles of the visceral organs make them work like

machines all through the life period. The muscle cells function like small motors to produce the forces

responsible for the movement of the arms, legs, heart and other part of the body. Thus the highly

specialized muscle tissues are responsible for the mechanical processes in the body. Based on structure,

functioning and occurrence three different types of muscle tissues have been identified. They are the

skeletal, visceral and cardiac muscles:

Skeletal muscles or striped muscles : These muscles are attached to the bones. The muscle cells

are long and cylindrical. These voluntary muscles cause body movements.

Visceral muscles or Nonstriated muscles: These are found in the walls of the inner organs such as

blood vessels, stomach and intestine. The muscle cells are spindle shaped. These are involuntary

in nature.

Cardiac muscle : These are found in the wall of the heart. The muscle cells are cylindrical and

branched. The muscles are involuntary in nature.

Questionnaire # 1: MUSCULAR SYSTEM

1. What are characteristics of animals?

2. How muscles are divided?

3. What is the function of muscle cells?

4. What is the function of muscle tissue?

5. Where are the skeletal muscles?

6. What is the size and shape of the skeletal muscles?

7. Where are the visceral muscles?

8. What is the size and shape of the visceral muscles?

9. Where are the cardiac muscles?

10. What is the size and shape of the cardiac muscles?

Quick Check # 1:

Draw in the notebook the muscular system of the face with parts.

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Skeletal muscles.

The skeletal muscles are attached to bones by tendons. The tendons help to transfer the forces

developed by skeletal muscles to the bones. These muscles are covered by sheets of connective tissue

called fascia.

Tendons : These are connective tissue structures showing slight elasticity. They are like cords or straps

strongly attached to bones. The tensile strength of tendons is nearly half that of steel. A tendon having 10

mm diameter can support 600 - 1000 kg.

Fascia : These are assemblages of connective tissues lining skeletal muscles as membranous sheets.

The fascia may be superficial or deep. The superficial fascia is a layer of loose connective tissue found in

between skin and muscles. The deep fascia are collagen fibres found as a tough inelastic sheath around

the musculature. They run between groups of muscles and connect with the bones.

Shapes of muscles

There is a wide variety of shapes and sizes in muscles. Based on general shape and the orientation or

muscle fibres in relation to the direction of pull, they can be grouped into two classes.

Parallel : These muscle fibres are parallel to the line of pull. The muscles may be flat, short,

quadrilateral or long and strap like. The individual fibres run the entire length of the muscle.

Oblique : These muscle fibres are oblique to the line of pull. The muscles may be triangular or

pennate (feather-like). The pennate forms may be unipennate, bipennate, multipennate or

circumpennate. Some muscles have a spiral or twisted arrangement.

Questionnaire # 2: MUSCLES

1. What are tendons?

2. What is the function of tendons?

3. What is fascia?

4. What is superficial fascia?

5. What is deep fascia?

Quick Check # 2:

1. What is the shape and size of the parallel muscles?

2. What is the shape and size of the oblique muscles?

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Distribution of muscles

I. Muscles of the head

There are two groups of muscles. They are craniofacial and masticatory muscles. The craniofacial

muscles are related to eye orbital margins, eyelids, nose, nostrils, lips, cheeks, mouth, pinna, and the

scalp. These muscles are also known as muscles of facial expression. Among these muscles those that

are related to the lip movement are significant. The facial expression is mostly due to lip movement and

positioning of the lips. Such thought related movements are caused by several muscles associated with

lips and the skin around the mouth. Since orbicularis oris and buccinator muscles provide lip movement

for kissing posture they are known as “kissing muscles”. Smiling is accomplished by zygomasticus major

and minor, levator anguli oris and risorius. The muscles of the lips can also provide expressions such as

sneering and frowning. The chin dimples are located between the mentalis muscles

The masticatory (or speech) muscles move the mandible of the lower jaw. The muscles responsible for

this movement are masseter temporalis and pterygoid. Tongue movements are caused by intrinsic and

extrinsic muscles. Swallowing of food is facilitated by several muscles related to the mouth, roof of

pharynx, uvula and other regions.

II. Muscles of the Neck region.

The movements of the neck region are caused by cervical, suprahyoid, infrahyoid and vertebral muscles.

III. Muscles of the Trunk region.

The muscles of the vertebral column help to bend and rotate the body. These are strong back muscles

that help the trunk to maintain erect posture. The most prominent muscles of this region are the erector

spinae, longissimus and spinalis.

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Four important thoracic muscle groups are associated with the process of breathing. While the process of

inspiration is due to scalene and external intercostal muscles, the expiration is performed due to internal

intercostals and transverse thoracis. Major breathing movement is due to diaphragm, a curved

musculofibrous sheet that separates thoracic and abdominal cavities.

Abdominal muscles can aid in forced expiration, vomitting, defaecation, urination and childbirth.

The inferior opening of the pelvic bone is covered by pelvic diaphragm muscles. Below these muscles

perineum is pressent. The perineum and other “subfloor” muscles form the urogenital diaphragm. Pelvic

and urogenital diaphragm may get strecthed in pregnancy due to weight of the foetus. However by specific

exercises they can be strengthened.

Questionnaire # 3: DISTRIBUTION OF MUSCLES:

1. Where are the craniofacial muscles?

2. What is the function of the muscles of facial expression?

3. Where are the masticatory muscles?

4. What is the function of the masticatory muscles?

5. What are the most prominent muscles in the trunk?

6. What is the function of the abdominal muscles?

Quick Check # 3:

Draw in the notebook the muscular system of the trunk with parts.

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IV. Muscles of the upper limb.

The hands are attached to the pectoral girdle and to the vertebral column by large conspicuous muscles

such as trapezius, rhomboid major and minor, levator scapulae and lattissimus dorsi.

The trapezius is a flat, triangular muscle. It extends over the back of the neck and upper thorax. It

maintains the level and poise of the shoulder. It helps to rotate the scapula forward, so that the arm can be

raised above the head. It helps to bend the neck backwards and laterally.

Latissimus dorsi is a large flat triangular muscle. It is a conspicuous muscle stretching over the lumbar

region and lower thorax. This muscle is useful in adduction, extension and medial rotation of the humerus.

It helps in the backward swinging of the arm. By raising the arm above the head it helps to pull the trunk

upwards and forwards. It is useful in violent expiratory activities such as coughing or sneezing. It helps in

deep inspiration.

Serratus anterior and pectoralis major connect the ribs to the scapula. Pectoralis major extends from the

upper thorax and abdomen to act on the humerus. It is a fan shaped muscle. It spreads between the

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clavicle and the 7th costal cartilage in the front of the chest. It helps to swing the extended arm forward

and medially. It helps in climbing. It is active in deep inspiration.

The muscles of the upper arm are the coracobrachialis, biceps, triceps and brachialis. The

coracobrachialis arises from the coracoid bone in the shoulder and ends in the humerus of the upper arm.

It helps to move the arm forward and medially. The biceps brachii is a large fusiform muscle. It has two

proximal heads for attachement. They are connected to the coracoid and shoulder joint. The lower head

ends in the radius of the lower arm. It is a powerful muscle causing flexing of the hand. The triceps arises

by three heads from scapula and upper part of humerus on the posterior side. The wrist, hand and finger

movements are caused by several extrinsic and intrinsic hand muscles. A detailed study of them could be

made in higher classes.

V. Muscles of the lower limb.

Thigh movements are caused by anterior, postereolateral

and deep muscles. The anterior muscles are the iliacus

and psoas major which help to flex the thigh. The gluteus

maximus form the mass of the buttocks region. Leg

movement is caused by the anterior thigh muscles,

quadriceps femoris and sartorius. The sartorius is the

longest muscle of the body. It runs from the hip to the

knee. Muscle movement of ankle foot and toe are caused

by several groups of extrinsic and intrinsic muscles. A

detailed study of them could be made in higher classes.

Questionnaire #4: UPPER AND LOWER LIMB

1. Where are the hands attached?

2. Where the trapezius extend?

3. What is the function of the trapezius?

4. Where the latissimus dorsi stretch?

5. What is the function of the latissimus dorsi?

6. What are the muscles that make up the upper

arm?

7. What muscles cause movements of the thigh?

8. What muscles cause the movement of the leg?

9. What muscles cause movements of the ankle,

feet and toes?

Quick Check # 4:

Draw in the notebook the muscular system of the upper and lower limb with parts.

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ASPECTS TO EVALUATE

YES

NO

I didn’t have any difficulty along the development of the worksheet.

I developed all the activities in order and dedication.

I felt myself comfortable doing all the activities.

I reinforced and acquired new knowledge to the activities planned in the

worksheet.