Tissue

Group of cells having similar characteristics and function combined together to form specific function in body are known as tissue.

OR

Group of Cells combined together to form Tissue .

Classification of tissue :

(1)Epithelial Tissue

Simple and Stratified

Simple Epithelial Tissue

• Squamous Epithelium

• Cuboidal Epithelium

• Columnar Epithelium

• Ciliated Epithelium

Stratified Epithelium Tissue

(1) Stratified Squamous Epithelium Tissue:

• Keratinized Tissue

• Non Keratinized Tissue

(2) Transitional Epithelium Tissue

(2)Connective Tissue :

▪ Loose Connective Tissue

▪ Dense Connective Tissue

▪ Fibrous Tissue

▪ Elastic Tissue

▪ Lymphoid Tissue

▪ Adipose Tissue

(3)Muscle Tissue :

• Skeleton Muscles

• Smooth Muscles

• Cardiac Muscles

(4)Nervous Tissue :

• Excitable Cells

• Non Excitable Cells

Simple Epithelium Tissue :

Simple Epithelium Tissue is divided into four types

(1)Squamous Epithelium:

Simple layer of cells are present on basement membrane.

Appearance - flat cells Found in body parts :

• Heart

• Blood vessels

• Lymphatic vessels

• Pleura of lungs

(2)Cuboidal Epithelium :

▪ Single layer of cells are found on basement membrane

▪ Appearance – Cube shaped Cells

▪ Found in body parts :

▪ Kidney Tubules ▪ Glands

(3)Columnar Epithelium :

▪ Single layer of cells are found on the basement membrane.

▪ These cells are rectangular in shape.

▪ Columnar Epithelium consists of mucus secreting cells known as goblet cells.

▪ Found in stomach, intestine, uterus.

(4)Ciliated Epithelium :

▪ Ciliated Epithelium is composed Of Cilia.

▪ Cilia are hair like projections, which help in movement .

▪ Found in Uterine tube and respiratory tract in trachea, lungs and in reproductive organs such as ovum .

(2) Stratified Epithelium

(1)Stratified Squamous Epithelium :

Keratinized Tissue :

▪ Keratinized Tissue Is made up of keratin protein, which protects the tissue from wear and tear.

▪ Found in nails and hairs .

Non keratinized tissue :

These tissue provides softness to body part

▪ They are found in wet areas of body such as mouth, vagina, Pharynx and oesophagus .

(2)Transitional Epithelium :

▪ Multiple layers of cell are present on the basement membrane.

▪ The cells can vary in shape and size.

▪ The cells are almost Pear in shape.

▪ Found in uterus

▪ Urethra

▪ Urinary Bladder

Function of Epithelial tissue :

▪ Protection : covers the body cavities and give protection from wearing and tearing.

▪ Absorption and secretion.

Connective Tissue :

▪ Connective tissue is the most abundant tissue found in body, approximately 60 to 70 percent.

▪ Found in almost all body part.

Cells of connective Tissue :

(1)Fat Cells :

▪ These cells are present in adipose tissue, also known as adipocytes

. (2)Macrophages :

▪ Macrophages are irregular in shape.

▪ They are involved in defense mechanism of body.

▪ Phagocytosis involve the engulfing of foreign body as a food by the macrophages.

▪ Macrophages are found in different body parts.

▪ They are known by different names, according to the site of the Body.

▪ In a liver Kupffer cells

▪ In blood monocyte

▪ In lymph node fibroblast

(3)Fibroblast Cells :

Fibroblast Cells produce elastic and collagen fiber.

Fibroblast cells are found in liver and lymphoid system.

They are involved in wound healing.

(4) Mast Cells :

Mast Cell structure is similar to Basophils cells.

They are found in liver blood vessels, spleen and lymphoid tissue

Mast cells produce two substance histamine and heparin.

Histamine is involved in hypersensitive reaction.

Heparin is produced as an anticoagulant.

Types Of Connective tissue :

(1)Loose Connective Tissue :

▪ Mast cells, macrophages, and fat cells are distributed in body.

All These Cells are interconnected with each other through a semi solid mass of Matrix, and are loosely arranged.

▪ They provide strength and elasticity to body parts.

▪ Present in muscles, nerves, blood vessels, elementary canal, and skin.

(2) Dense Connective Tissue :

(1) Fibrous Tissue :

▪ Fiber are arranged in the form of bundle with very little matrix present between them.

▪ Few cells are present in fibrous tissue.

▪ Fiber are more commonly found.

▪ Fibrous tissue form tendons and ligaments in body.

▪ Cover the outer part of organs such as kidney, bone, lymph node, etc.

(2) Elastic Tissue :

▪ Elastic tissue has a property of extension and recoiling.

▪ It provides elasticity to body organs.

▪ Found in myocardium

▪ Blood cells

▪ Trachea

▪ Vocal cord

(3) Lymphoid Tissue :

▪ It contains white Blood cells and Reticular cells.

▪ Lymphoid tissue is found in :

▪ Spleen

▪ Lymphatic tissue

▪ Lymphatic vessels

▪ Liver

▪ Kidney

(4) Adipose Tissue :

(1) White Adipose Tissue :

▪ White Adipose Tissue is found in Adult body.

▪ The Amount of White Adipose Tissue present depends upon the amount of intake of energy and expenditure of energy.

▪ Found under the Skin, Between muscles

▪ In Kidneys

▪ Under Eyes

(2) Brown Adipose Tissue :

▪ Brown adipose tissue is found in neonates.

▪ Brown adipose tissue, when metabolized it produces more heat and less calories.

▪ It maintains the body temperature of neonates and prevent from hypothermia.

(3) MUSCLE Tissue :

(1) Skeleton Muscles :

▪ These type of muscles are attached to bones.

▪ These muscles are under our voluntary control.

▪ Skeletal muscle fiber contain light and dark bands.

These fibers are arranged in alternating manner.

▪ Skeleton muscle function :

▪ Helps in producing body movements.

▪ Help in maintaining body posture.

▪ Help in providing flexibility to joints.

▪ Help in maintaining body temperature.

(2) Smooth Muscle Fiber :

▪ These are Non Striated muscles.

▪ They are not under our voluntary control.

▪ Smooth Muscles help in contraction

and Relaxation of blood vessels and organs .

▪ Smooth muscles are found in :

▪ Heart

▪ Blood vessels

▪ Urinary system

▪ Uterus

Ureter

▪ Respiratory tract

▪ Alimentary canal

(3) Cardiac Muscle Fiber:

▪ Cardiac muscles are also known as non striated muscles.

▪ They are involuntary muscles.

▪ Cardiac muscles are specialized muscle tissue present in

heart and blood vessels.

▪ These muscles help in contraction of myocardium

and helps in maintaining normal heart functioning.

▪ Cardiac muscles are present in larger blood vessels.

Example, Aorta and Pulmonary artery.

(4) Nervous Tissue :

(1)Excitable Cells :

▪ Nervous tissue is composed of neurons.

▪ The Neurons are the Cell which carry electrical

signals from the sensory organ to the brain.

▪ Helps in sensory and motor function.

▪ Excitable neurons receive and conduct nerve impulses to brain.

(2) Non Excitable Cells :

▪ Non excitable cells do not conduct nerve impulses.

▪ They are known as Glial Cells.

▪ They provide nourishment to excitable Cells.

Function of Tissue in Body :

▪ Connective Tissue provides support and stability to the body organs.

▪ Muscle tissue helps in movement and maintain the posture and alignment of body.

▪ Epithelial tissues secrete saliva, enzymes, mucus, sweat and other substances.

▪ Connective tissue help in storing the fat in body.

▪ Connective tissue help in repairing the other body tissues.

▪ Nervous tissue control and coordinate the activities of body.