There   are   four   types   of   tissues   found   in   animals namely   epithelial   tissue,   connective   tissue,   muscle   tissue,   and  nervous   tissue.

Epithelial tissue

Epithelial tissue shields the surface of all internal as well as external organs. All layers and organs in the body are lined by a group of tissues which are commonly referred to as epithelium. This animal tissue is highly permeable as it plays a significant role in the exchange of substances across the cells and helps in maintaining the osmoregulation. Depending on the number of layers, the epithelium is divided into two types viz.simple epithelium and compound epithelium. The main functions of epithelial tissue include protection, secretion, sensation, and absorption. They act as a protective barrier against injury and invasion of pathogens like viruses, bacteria, etc. Some epithelial also secrete substances like digestive juices or absorb nutrients and prevents water loss from the body.

Connective tissue

Connective tissue supports in connecting or separating other tissues or organs of the body as the name suggests. A fibrous connective tissue is strong and is found in areas like ligaments, which basically connects bones to one another. Connective tissues happen to be the most abundant tissues of complex animals as they include cartilage, bone, adipose, and blood. All connective tissues except blood tend to secrete structural proteins called collagen or elastin. There are different types of connective tissues like Loose Connective tissue, Dense Connective tissue, and Specialized Connective tissue.

Muscular tissue

This animal tissue is again divided into three types which are cardiac, smooth, and skeletal. Skeletal is a voluntary type which is made by the contraction of skeletal parts. The smooth tissue found in walls of blood vessels and internal organs are an involuntary type. The last type viz. cardiac muscle is found only in the walls of the heart and it is also involuntary in nature.

The neural or nerve tissues happen to exert control over the body’s responses to changing conditions. Neurons, the excitable cells are the units of the neural system. It is comprised of specialized cells which receive stimuli and conduct the impulses to and from different parts of the body. Its functions include processing and transferring information.

Nervous   tissue   is   specialized   for   communication   and   composes   the   brain,   spinal   cord,   and   peripheral  nerves.   The   tissue   consists   of   two   major   cell   types:    neurons   and   glial   cells.      Neurons   communicate   with  each   other   via   electrical   and   chemical   signals.   They   have   nucleated   cell   bodies   and   two   types   of  elongated   cellular   processes:    dendrites   –   which   receive   signals,   and   axons   –   which   send   signals.  Glial   cells   are   the   support   cells   of   nervous   tissue.      There   are   several   different   types   with   various  functions,   including   maintaining   proper   ion   concentrations   in   the   fluid   surrounding   neurons,   generating  myelin   (an   insulating   material   that   surrounds   some   axons),   and   cleaning   up   debris.

Hello Aspirant!

There are four types of animal tissue , their function is given below  "-

• epithelial tissue :- It's function  include secretion, selective absorption, protection, transcellular transport, and sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue , through the basement membrane.
• connective tissue :- The primary functions of connective tissues include transportation of nutrients and metabolites through direct diffusion between organs and connective tissue proper.
• muscle tissue :- It helps in movement and the maintenance of posture and body position.
• nervous tissues:-The primary function of nervous tissue is to receive stimuli and send the impulse to the spinal cord and brain .

Thankyou