This video consists of animal tissues chapter in simple and clear way. which helps students to understand easily.
Animal cells with the same structure and function are grouped together to form tissues. There are four types of animal tissues: epithelial tissue, connective tissue, muscle tissue and nervous tissue.Epithelial tissues are formed by cells that cover surfaces (e.g. skin) and line tubes and cavities (e.g. digestive organs, blood vessels, kidney tubules and airways). Epithelial tissue usually consists of a single layer of cells, however in certain cases there may be more than one layer. All epithelial tissues are free surfaces attached to the underlying layers of a basement membrane.
There are different types of epithelial tissue which are named according to the number of layers they form and the shape of the individual cells that make up those layers. Simple epithelium refers to a single layer of cells. Stratified epithelium refers to two or more layers of cells. Squamous epithelium refers to flattened cells, cuboidal epithelium refers to cells that are cube-shaped and columnar epithelium refers to vertically elongated cells. Ciliated epithelium refers to epithelial cells that contain many tiny hair-like projections.
General functions of epithelial tissue
Provides a barrier between the external environment and the organ it covers.
Specialised to function in secretion and absorption.
Protects organisms from microorganisms, injury, and fluid loss.
Excretes waste products such as sweat from the skin.Skeletal and cardiac muscle are striated. Striated muscle cells are striped, with regular patterns of proteins responsible for contraction. Striated muscle contracts and relaxes in short bursts, whereas smooth muscle contracts for longer.
1. Skeletal muscle is a voluntary muscle. It is striated in appearance. Skeletal muscle tissue has regularly arranged bundles. It is anchored by tendons and is used to effect skeletal muscle movement, such as locomotion, and maintain posture. The muscles have a reflex action but can also respond to conscious control.
2. Smooth muscle is an involuntary, non-striated muscle with tapered ends. It is found within the walls of blood vessels such as arteries and veins. Smooth muscle is also found in the digestive system, urinary tract and in the trachea. It is responsible for involuntary rhythmic contractions of peristalsis, required for moving food down the alimentary canal, and for the dilation and construction of blood vessels to control blood pressure.
3. Cardiac muscle is the major tissue making up the heart. It is an involuntary muscle that is striated in appearance. However, unlike skeletal muscle, cardiac muscle connects at branching, irregular angles. The connected branches help with coordinated contractions of the heart
0 Comments