Biology presentation

Biology PresentationBy Rithesh Darish, 9-V

The Indian High School, Dubai

Animal tissues Animal tissues can be grouped into four

basic types: 1. Connective Tissue2. Muscular Tissue3. Nervous Tissue4. Epithelial Tissue Multiple tissue types comprise organs

and body structures.

Connective tissuesConnective tissues are fibrous tissues. They

are made up of cells separated by non-living material, which is called extracellular matrix.

Connective tissue gives shape to organs and holds them in place. Both blood and bone are examples of connective tissue.

As the name implies, connective tissue serves a "connecting" function. It supports and binds other tissues. Unlike epithelial tissue, connective tissue typically has cells scattered throughout an extracellular matrix.

The main features of the connective tissue are :-

1. They have cells or fibres (white and yellow).

2. Matrix in which the connective tissues are embedded or suspended. Thus matrix acts as medium.

Connective Tissue Category Tissue Types

1.  Fluid Connective Tissues

Blood and Lymph

2.  Connective Tissue Proper

Loose and Dense Connective Tissues

3.  Supportive Connective Tissues

Cartilage and Bone

Muscular Tissue

Muscle cells form the active contractile tissue of the body known as muscle tissue or muscular tissue. Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs.

Muscle tissue is separated into three distinct categories: visceral or smooth muscle, which is found in the inner linings of organs; skeletal muscle, in which is found attached to bone providing for gross movement; and cardiac muscle which is found in the heart, allowing it to contract and pump blood throughout an organism.

Muscle types are also described as voluntary or involuntary.  These terms imply some muscles are controlled voluntarily while others

are not.  Think about this for a moment!  You can control the muscles moving your fingers but you cannot consciously control contractions of muscles in your heart or stomach.

 Intuitively, you already know cardiac and smooth muscles are involuntary types.  

Skeletal, the muscle type attaching to bones can be consciously controlled and therefore is a voluntary type. The three muscle types we will view are then: 

Skeletal-voluntary muscles attached to skeletal elements and cartilage. 

Cardiac-involuntary muscles making up the myocardium of the heart. Smooth-involuntary muscles in the walls of hollow organs, blood

vessels, and all other body locales where muscles perform work(i.e. think of the eye with its pupillary dilation or constriction).

Some muscles have the ability to contract independently without stimulation by the nervous system. Smooth muscle and cardiac muscle possess this ability, they are subsequently called autorhythmic types!

Nervous TissueNervous tissue includes all cells that provide

communication between other tissue types.  Think of nervous tissue as the

communication network of the body, consisting of a master computer(the brain) linked to multiple sites via complex cabling and wires(the spinal cord and nerves).  

Various sensing devices(receptors) provide input to the computer and when necessary the computer controls machine response(effectors such as muscles or glands).

Epithelial TissueEpithelial tissues form an covering on an

external or internal surfaces of the animals. Epithelial tissue also called protective tissue in animal body . The cells are closely and arranged on a very thin gelatinous basement membrane.

An epithelial tissue maybe composed of one (simple epithelium) or more layers of cells (compound epithelium). The skin, surface layers of the mouth, alimentary canal, lungs etc. are made of epithelial tissues.

It also form a barrier to keep the body system separate.

1. Simple squamous: A single layer of squamous cells that are thin, flat cells that resemble fried eggs. They form the lining of cavities such as the mouth, blood vessels and lungs.

2. Simple cuboidal: One layer of cuboidal cells which are plump cells that are roughly square or cube-like in shape. These cells are found in glands, duct and portions of the kidney tubules.

3. Simple columnar: A single layer of tall, skinny cells (column shaped) that are found in places like the lining of the intestine and gallbladder.

4. Stratified squamous: Many layers of cells are present, the topmost layer is made up of squamous cells. Stratified squamous cells are often described as looking like "piles of tiles." This is the type of epithelium that makes up the skin surface and lining of the mouth, through and esophagus.

5. Stratified columnar: Many layers of cells, the topmost layer is made up of columnar cells. Epithelium of this type is found in the mammary ducts and epididymus.

6. Glandular: Columnar and cuboidal cells often become specialized as gland cells which are capable of secreting substances such as enzymes, hormones, mucus, sweat and saliva. Examples include the salivary, sweat and adrenal glands.

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