Biology Science 1

[ M.S. System ] - Muscular System

3 Types of muscles 

1. Cardiac muscle 

2. Skeletal muscle 

3. Smooth muscle 

Structure of Skeletal Muscle

> Multi nucleated 

> Striped appearance 

> Made up of elongated cells called Muscle Fibres 

> Muscle Fibres are bound together by connective tissue into small bundles called fasciculi 

Muscle Attachment 

1. ORIGIN 

> The end where no movement occurs 

2. INSERTION 

> The end where movement occurs 

*Muscle Coordination 

> 2 Types of muscles with opposite functions :

1. Agonists > When muscles contract during movement 

2. Antagonists > When muscles relax during movement 

> Muscle Tone* 

- Steady and partial contraction of muscle fibres 

- Present at all times 

- Keep body posture normal 

*Muscles Activity 

> Over-contraction of muscle will result in muscle fatigue 

> Caused by prolonged or repeated simulation of a muscle :

- Oxygen & glucose used up 

- Accumulation of waste product

> Interfere muscle ability to contract and relax normally 

Functions of Skeletal Muscles

Heat generation from movements aids in maintaining the body temperature 

Muscular contraction produces : 

> skin movement that produces facial expression 

> to maintain posture 

Skeletal movement allows :

> eating, breathing, locomotion ( movement of the arm while walking ) etc. 

Muscles of the Skull 

1. Occipitofrontalis 

2. Temporalis 

3. Obicularis oculi 

4. Orbicularis oris 

5. Masseter 

6. Sternocleidomastoid 

7. Trapezius 

8. Platysma 

Muscles of the Arm 

1. Biceps*

2. Triceps*

3. Deltoid*

4. Pectoralis major* ( chest muscle )

5. Brachialis

6. Latissimus dorsi

 Muscle of the Abdomen 

Functions : Contract the abdominal organs & Flexion of the Vertebral column 

Muscles of Pelvic Floor 

Function : To support weight of abdominal and pelvic organs 

Gluteal muscles

Function : To extend the hip 

Located : From the buttocks 

- END -