Topic 38 - Muscle tissue – general features. Types of muscle tissue

Muscle tissue – general features. Types of muscle tissue

General features:

• Muscle tissue is the 4th basic type of tissue
• Composed of cells that optimise the universal cell property of contractility
• All muscle cells are of mesodermal origin and differentiate by a gradual process of cell lengthening with abundant synthesis of myofibrillar proteins actin and myosin
• Cytoplasm of muscle cells is called sarcoplasm
• SER is called the sarcoplasmic reticulum
• Muscle cell membrane and its external lamina is called the sarcolemma
• Unit of muscle tissue is muscle fibre
• Muscle cells are elongated and this shape functions well for contraction
• Myofibrils are thread-like contractile structures in these cells
• Myofibrils are composed of myofilaments of the contractile proteins actin and myosin

Properties of muscle tissue:

• Conductivity – the ability of a muscle to conduct electrical impulses across the membrane
• Contractibility – the ability of a muscle to shorten and produce energy
• Elasticity – ability of a muscle to return to its original length without damage
• Irritability – ability of muscle to respond to stimulus

Functions of muscle tissue:

• Movement of the body as a whole
• Body posture stabilisation
• Volume regulation of internal organs – sphincters
• Movement of substances within living organisation – blood, lymph, air, food, fluids, urine, sperm
• Heat production – involuntary
• Contractions of the skeletal muscles (trembling)

There are 3 types of muscle tissue:

1. 1. Skeletal muscle
2. 2. Cardiac muscle
3. 3. Smooth muscle