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ANIMAL TISSUE

ANIMAL TISSUE
One of the body composers are muscles and bone. Muscle and bone who give shape to animal’s body in composed of different tissues, and it depends on the function and structure. And so does the other composer, each part is consisted of several tissues. Meanwhile, animal tissues consisted of epithelial tissue, connective or supporting tissue, muscular tissue and nervous tissue.
1.      Epithelial tissue
Epithelial tissue is tissues formed by dense cells composed in flat like a membrane that covering outer part or coating the body cavity or an organ. Based on its function, epithelial tissue is divided into protecting epithelium, secretion epithelium, sensory epithelium, and absorption epithelium. Protecting epithelium covers or coats body/duct cavity that relates to body surface. Secretion epithelium produces a substance and secretes it. There are two types of secretion epithelium, namely endocrine and exocrine. The example of endocrine gland are hypophysis and exocrine is sebaceous gland (oil gland). Sensory epithelium can be found around the sense organs, for example in tongue. Absorption epithelium is epithelium that does actively the absorption, for example in the intestine and kidney’s nephron.
Based on the shape of its composer cells, this tissue is divided into flat, dome, and cylindrical epithelium. Based on its amount of layers, this tissue is divided into two, namely simple epithelial tissue and stratified epithelial tissue.
a.      Simple squamous epithelium
Simple squamous epithelium is flattened or rather thin with a nucleus in the middle and merely in the form of cell rows. This kind of epithelium has the function to allow diffusion process and filtration through its selective permeable surface.
b.      Simple cuboidal epithelium
Simple cuboidal epithelium has box-shaped cells with the nucleus in the middle. The functions of the epithelium are secretion and absorption. Simple cuboidal epithelium can be found in glands layer, ovary surface, and inner surface of the lens, pigmented epithelium in retina and kidney tubules.
c.       Simple columnar epithelium
Simple columnar epithelium has long cells like tube with the nucleus in the lower part. The functions of this epithelium are secretion, absorption, protection, and lubricator. Usually, there are cilia and mucous to be found in its surface, for example cylindrical epithelium in oviduct. This epithelium can be found in stomach, intestine (microvillus and villus), digestive glands, gall bladder, digestive tract, upper respiratory system and uterus (womb).
d.      Stratified squamous epithelium
Stratified squamous epithelium has a function as protection. This epithelium can be found in epidermis of vagina, mouth, oesophagus, anus, and distal point of urethra.
e.      Stratified cuboidal epithelium
Stratified cuboidal epithelium has a secretion function. This epithelium can be found in sweat gland and oil gland, epithelium of ovary and testicles.
f.        Stratified columnar epithelium
Stratified columnar epithelium has secretion and movement function. This epithelium can be found in the surface of larynx, nose, soft palate, urethra, secretory tract, saliva gland and mammary gland.
g.      Pseudostratified columnar epithelium
This epithelium has as if two layers, but they only have one layer. This is caused by the cells that undergo unequal development that there are cells which risen and some of them are shortened. The functions of this epithelium are protection, secretion, and substance movement tract through the surface. The pseudostratified columnar epithelium can be found in large excretory tract, male reproductive tract, nasal cavity, and respiratory tract.
h.      Transitional epithelium
Transitional epithelium has cells that can change in shapes form flat to cube-shaped. Under a pressed condition, the cells will be in flat shape. When not depressed, the cells will be in cubes-shape. This epithelium can be found in urine bladder, ureter, urethra, and kidney. If the urine bladder is empty, the epithelial cells are in cube-shaped. Contrarily, if the urine bladder is full, the epithelial cells are flattened.
i.        Glandular epithelium
The function of glandular epithelium are for synthesis process, storage and product secretion. This epithelium can be found in dermal gland, mammary gland, digestive gland, and endocrine gland.

2.      Connective or supporting tissue
The connective or supporting tissue is a tissue with fibers to support cells in the tissue. The function of this tissue is supporting other body’s tissues and covering weak organs. The kinds of connective/supporting tissues are among other things, fatty tissue, loose fibrous connective tissue, dense fibrous connective tissue, bone tissue, cartilage tissue, blood tissue, and lymph tissue.
a.      Fatty tissue (adipose)
Fat accumulation in the body can be found in several sites, among other things in the heap, waist, abdomen or arms, usually in women. The function fat accumulation in the body is to keep the body temperature. Other function of fatty tissue is as place to store fat, food reserves, as bearing for protection and isolation to the heat loss. The shape of fatty tissue is loose and composed of polygon or round-shaped fatty cells with thin cell wall.
      Fatty tissue can be found in entire body, namely under the skin layer, around the kidney, in the bearing around the joints and in the marrow of long bone.
b.      Loose fibrous connective tissue
The function of this tissue is surrounding various organs: supporting nervous cells and blood vessel: store the glucose, mineral salts and water: supporting tissue and organs. This tissue has large matrix with considerable cells and fibres attach inside (fibroblast, plasma cell, macrophage and white blood cells). Loose fibrous connective tissue is composed of collagens and elastin. This tissue can be found around and among the organs or covering muscles, blood vessels and nerves.
c.       Dense fibrous connective tissue
The functions of dense fibrous connective tissue are as supporting and protection. Besides, it connects also muscle and bone(tendon), and between bones (ligament). Dense fibrous connective tissue is composed of flexible but inelastic collagen tissue. Dense fibrous connective tissue can be found in fascia, tendon membrane, ligament and tendon.
d.      Bone tissue (osteon)
The function of bone tissue are to form the skeleton that supports the body and protects soft body parts, and binding the skeleton’s muscle. Bone tissue has calcareous intercellular matrix. This is caused by deposit of mineral salts, namely CaCO3 and Ca(PO4)2. Bone tissue undergoes calcification, which is a process of calcium addition to the bone that the bone becomes strong. Based on the matrix of its composer, the bone is divided into two types, compact bone tissue (hard bone) and spongy bone tissue. Compact bone tissue has solid matrix, while spongy bone tissue has porous matrix.
      In bone tissue, mineral substance is stored in bone matrix that forms thin layers called lamella. Lamella is composed concentrically surrounding the Haversian canal, which is an interconnected and prolonged canal. Lamella and haversian canal form a Haversian system.
e.      Cartilage tissue
The function of cartilage tissue are giving strength and supporting embryo’s skeleton and parts of mature skeleton. This tissue has many matrices, elastic and fulfilled with cartilage cells. Cartilage cells positioned in a cavity and its outer part is covered by fibrous. There are three cartilage tissues, namely hyaline cartilage, fibrocartilage, and elastic cartilage.
f.        Blood tissue
The functions of blood tissue are, among other things, to carry food essence to the body cells and transport discharge substances resulted from metabolism out of the cell: transport oxygen and carbon dioxide: fight the disease germs. Blood tissue is characterized by its liquid composition (called plasma) and solid composition that is the blood itself. There are several blood cells: among other things are erythrocytes (red blood cells), leucocytes (white blood cells) and thrombocyte (blood platelets).
g.      Lymphatic tissue
The function of the lymph tissue is to carry protein, fat and other substances from all tissues to the circulatory system. The characteristics of lymph tissues are, among other things, formed from water, glucose, fat and salts, its cellular component is in the form of lymphocyte and granulocyte. Lymphatic fluid plays role in immune system.

3.      Muscular tissue
The function of muscular tissue is to do movement in various parts of the body. Muscular tissue can do contraction because they have long contractile protein that contains smooth fibres called myofibrils. Based on its nature, characteristic and function, muscular tissue is divided into smooth muscle, skeletal (striated) muscle and cardiac muscle.

4.      Nervous tissue
Nervous tissue is consisted of branches nervous. Neurons are capable to react. This capability is included irritability (capability or neurons to respond to the environmental change) and conductivity (capability of neurons to bring nerve impulse or message to the central nervous system). Nervous consisted  of neuron body that composed of cell plasma and nucleus. There are granules in the cell plasma that come from clumps of endoplasmic reticulum called Nissl body. Axon or neurite is protrusion of neuron body with a long size. Axon is covered by axoplasm called myelin sheath. Dendrite is protrusion of neuron body with s short size.
            The collection of neurons will form ganglion. A group of cells with function to give nutrient and materials for the living of neuron is called neuroglia. Neuroglia is consisted of myelin sheath and neurilemma.