Tiêu đề 3. ELEMENTARY TISSUES OF THE HUMAN BODY.pdf ✅

PHARMD GURU Page 1 ELEMENTARY TISSUES OF THE HUMAN BODY TISSUES:  Tissues of the body consist of large number of cells. They are classified according to size, shape and functions of these cells. There are four main types of tissues are there. They are: 1. Epithelial tissue. 2. Connective tissue. 3. Muscle tissue. 4. Nervous tissue. ELEMENTARY TISSUES OF THE HUMAN BODY: EPITHELIAL, CONNECTIVE, MUSCULAR AND NERVOUS TISSUES-THEIR SUB- TYPES AND CHARACTERISTICS
PHARMD GURU Page 2 1. EPITHELIAL TISSUE: It covers the whole body inside and out. They form the skin, and the inner lining of the body cavities such as the stomach and the intestines. FUNCTIONS:  Can reproduce quickly in case of damage or injury. That's why your skin heals so quickly when you get a cut.  Absorption of nutrients from food,  The secretion of hormones in the glands,  Saliva in the mouth,  Perspiration in the skin, and  Enzymes indigestion. DIFFERENT TYPES OF EPITHELIUM: Epithelial tissue may be: 1. SIMPLE : A single layer of cells. 2. STRATIFIED : Several layers of cells. 1. SIMPLE EPITHELIUM: Consists of single layer of cells and divided into 4 types: (A) SQUAMOUS EPITHELIUM: Composed of single layer of flattened cells. The cells fit closely together like flat stones, forming a thin and very smooth membrane. Diffusion takes place freely through this thin, smooth, inactive lining of the following structures.
PHARMD GURU Page 3 1. Heart. 2. Blood vessels. 3. Lymph vessels. 4. Alveoli of the lungs. (B) CUBOIDAL EPITHELIUM: This consists of cube-shaped cells fitting closely together lying on a basement membrane. It forms the tubules of the kidneys and is found in some glands. Cuboidal epithelium is actively involved in secretion, absorption and excretion. (C) COLUMNAR EPITHELIUM: This is formed by single layer of cells, rectangular in shape. Some absorb the products of digestion and other secretes mucus. Mucus is a thick substance secreted by columnar cells called goblet cells. (D) CILIATED EPITHELIUM: Found by columnar cells which have fine, hair like processes called cilia. The wave like movement of many cilia propels the contents of the tubes, which lie in one direction only.
PHARMD GURU Page 4 This is found lining the uterine tubes and most of the respiratory passages. In uterine tubes the cilia propel ova towards the uterus and in respiratory passages propel mucus towards the throat. 2. STRATIFIED EPITHELIA: Main function of this is, to protect underlying structures from mechanical wear and tear. There are 2 main types: (A) STRATIFIED SQUAMOUS EPITHELIUM: This is composed of a number of layers of cells of different shapes representing newly formed and mature cells. In the deepest layers the cells are mainly columnar and, as they grow towards the surface, they become flattened and are then shed. They are two types: 1. Non‐keratinized stratified epithelium. 2. Keratinized stratified epithelium.
PHARMD GURU Page 5 (B) TRANSITIONAL EPITHELIUM: This is composed of several layers of pear-shaped cells and is found lining the urinary bladder. It allows for stretching as the bladder fills. 2. CONNECTIVE TISSUE:  Connective tissues bind structures together.  Connective tissue includes tendons, ligaments, bone and cartilage. Other types of this tissue store fat, produce blood cells and destroy bacteria. FUNCTIONS OF CONNECTION TISSUE:  Binding and structural support.  Protection.  Transport.  Insulation. CELLS OF CONNECTIVE TISSUE:  Fibroblasts.  Fat cells.  Macrophages.  Leukocytes.  Mast cells. FIBROBLASTS:  These are large flat cells with irregular processes. They produce collagen and elastic fibres and a matrix of extracellular material.  Very fine collagen fibres sometimes called reticulin fibres are found in very active tissue, such as the liver and lymphoid tissue.  Collagen fibres formed during healing shrink as they grow old, sometimes interfering with the function of organ involved and with adjacent structures.