CELL AND TISSUE

PRESENTED BY

VIVEK DEV

CELLS

CELLS The cell is the basic structural, functional, and

biological unit of all known living organisms. They are often called the "building blocks of life” Mostly cells are microscopic (an average sized

cell is only one fifth the size of the smallest dot you can make on a sheet of paper with a sharp pencil)

Although they are minute, cells act as complex factories to carryout thefunctions of life.

CELL STRUCTURE

Cell membraneCytoplasmNucleusEndoplasmic reticulum (E.R)Golgi apparatusMitochondriaLysosomesPlasmidVacuoleRibosomeCentrioles

CELL MEMBRANE The cell membrane (also known as the plasma

membrane or cytoplasmic membrane) is a biological membrane that separates the interior of all cells from the outside environment.

It is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells.

The basic function of the cell membrane is to protect the cell from its surroundings.

The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix and other cells to hold them together to form tissues.

CYTOPLASM

Basically cytoplasm is the substance that fills the cell.

It is a jelly-like substance and it is made up of eighty percent water and is usually clear and colourless.

It serves as a molecular soup, it is in the cytoplasm where all the cellular organelles are suspended and are bound together by a lipid bilayer membrane.

The peripheral zone of cytoplasm is thick and jelly-like substance, known as the plasmogel. The surrounding area of the nuclear zone is thin and liquefied in nature and is known as the plasmosol

The cytoskeleton of the cytoplasm provides shape to the cell and it also facilitates movement. It forms a framework for the movement of organelles around the cytoplasm - most of the organelles are attached to the cytoskeleton.

NUCLEUS

The nucleus is a membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction.

It is the command center of a eukaryotic cell and is commonly the most prominent organelle in a cell.

The nucleus is the largest cellular organelle in animal cells. In mammalian cells, the average diameter of the nucleus is approximately 6 micrometres (µm), which occupies about 10% of the total cell volume

 The viscous liquid within it is called nucleoplasm. It appears as a dense, roughly spherical or irregular organelle.

The nucleus controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes).

ENDOPLASMIC RETICULUM (E.R)

E R is a type of organelle in the eukaryotic cells that forms an interconnected network of flattened, membrane-enclosed sacs or tube-like structures known as cisternae.

 The membranes of the ER are continuous with the outer nuclear membrane

It is of two types; smooth ER(absence of ribosome at outer surface)and rough ER (presence of ribosome at outer surface)

GOLGI APPARATUS

The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells

The Golgi apparatus is a major collection and dispatch station of protein products received from the endoplasmic reticulum

A major function is the modifying, sorting and packaging of proteins for secretion

. It is also involved in the transport of lipids around the cell, and the creation of lysosomes

. The sacs or folds of the Golgi apparatus are called cisternae

MITOCHONDRIA

The mitochondrion (plural mitochondria) is a double membrane-bound organelle found in all eukaryotic organisms, although some cells in some organisms may lack them (e.g. Red blood cells)

The main job of mitochondria is to perform cellular respiration. This means it takes in nutrients from the cell, breaks it down, and turns it into energy

This energy is then in turn used by the cell to carry out various functions

Also known as power house of cell  because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.

The number of mitochondria in a cell can vary widely by organism, tissue, and cell type. For instance, red blood cells have no mitochondria, whereas liver cells can have more than 2000

LYSOSOMES

A lysosome is a membrane-bounded organelle found in most animal cells.

They are spherical vesicles which contain hydrolytic enzymes that can break down virtually all kinds of biomolecules.

It is One of the key organelles involved in digestion and waste removal as hey contain digestive enzymes.

the interior of the lysosomes is acidic compared to the slightly basic cytosol

PLASMID

A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently

They are most commonly found in bacteria as small circular, double-stranded DNA molecules; however, plasmids are sometimes present in eukaryotic organisms

plasmids often carry genes that may benefit the survival of the organism, for example antibiotic resistance

plasmids usually are very small and contain only additional genes that may be useful to the organism under certain situations or particular conditions

. Plasmids are much used in the laboratory manipulation of genes.

VACUOLE

A vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protest, animal and bacterial cells

Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution

Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these.

It has no basic shape or size; its structure varies according to the needs of the cell.

It is surrounded by a membrane and functions to hold materials and wastes

. It also functions to maintain the proper pressure within the plant cells to provide structure and support for the growing plant

RIBOSOME

The ribosome is a complex molecular machine, found within all living cells, that serves as the site of biological protein synthesis

Ribosomes link amino acids together in the order specified by messenger RNA(mRNA) molecules.

Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum

CENTRIOLE

a centriole is a cylindrical cell structure composed mainly of a protein called tubulin that is found in most eukaryotic cells.

Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis

The position of the centriole determines the position of the nucleus and plays a crucial role in the spatial arrangement of the cell.

The main function of the centriole is to help with cell division in animal cells

MITOTIC CELL DIVISION

INTERPHASE

Interphase is the phase of the cell cycle in which a typical cell spends most of its life.

During this phase, the cell copies its DNA in preparation for mitosis

There are three phases in interphase G (Gap 1), in which the cell grows and

functions normally. During this time, a high amount of protein synthesis occurs and the cell grows (to about double its original size) - more organelles are produced and the volume of the cytoplasm increases.

Synthesis (S), in which the cell duplicates its DNA

G2 (Gap 2), in which the cell resumes its growth in preparation for division. The mitochondria divide and the cell continues to grow until mitosis begins

PROPHASE

In this phase, the chromosomes condense and thicken

Each duplicated chromosome appear as two identical sister chromatids

The mitotic spindle begins to form.

METAPHASE

In metaphase, the centromeres of the chromosomes convene themselves on the metaphase plate 

ANAPHASE

The spindle fibers begin to contract

This starts to pull the sister chromatids spart

At the end of anaphase a complete set of daughter chromosomes is found in each pole

TELLOPHASE AND CYTOKINESIS

During telophase, the effects of prophase and prometaphase   (the nuclear membrane and nucleolus disintegrating) are reversed.

Two daughter nuclei form in each daughter cell

The chromosomes reach the poles as the nuclear membranes re-form around each set of chromatids, the nucleoli also reappear

TISSUE

TISSUE  tissue is a cellular organizational level

intermediate between cells and a complete organ.  is an ensemble of similar cells from the same

origin that together carry out a specific function. The study of tissue is known as histology

TYPES OF TISSUE

CONNECTIVE TISSUE

CONNECTIVE TISSUE PROPER

LOOSE

DENSE

FLUID CONNECTIVE

TISSUE

BLOOD

LYMPH

SUPPORTING CONNECTIVE

TISSUE

CARTILAJE

BONE

MUSCLE TISSUE

SMOOTH MUSCLESKELETA

L MUSCLECARDIAC MUSCLE

EPITHELIAL TISSUE

SQUAMOUS EPITHELIUM

CUBOIDAL EPITHELIUM

COLUMNAR EPITHELIUM

TRANSITIONAL EPITHELIUM

NERVOUS TISSUE

EPITHELIAL TISSUE  Epithelial tissues line the cavities and surfaces

of blood vessels and organs throughout the body.

1.

EPITHELIAL TISSUESQUAMOUS EPITHELIUM

It has surface whose outermost (apical) layer consists of thin, flat cells.

 they may be composed of one layer of cells, in which case it is referred to as simple squamous epithelium, or it may possess multiple layers, referred to then as stratified squamous epithelium.

squamous epithelial cells have a polygonal appearance when viewed from above

CUBOIDAL EPITHELIUM cuboidal epithelia are epithelial cells having

a cube-like shape; that is, their width is approximately equal to their height.

They may exist in single layers (simple cuboidal epithelium) or multiple layers (stratified cuboidal epithelium) depending on their location (and thus function) in the body.

EPITHELIAL TISSUE

COLUMNAR EPITHELIUM

Columnar epithelial cells are epithelial cells whose height are at least four times their width.

 Columnar epithelia are divided into simple (or unilayered), and stratified (or multi-layered)

They are found in the inner lining of the intestine. They secrete digestive enzymes and absorb digested food.

TRANSITIONAL EPITHELIUM

Transitional epithelium is a type of tissue consisting of multiple layers of epithelial cells which can contract and expand.

 This tissue structure type is found in urothelium, including that of the urinary bladder, the ureters, and the superior urethra and gland ducts of the prostate.

They also functions as barrier between the lumen, or inside hollow space, of the tract that it lines and the bloodstream.

CONNECTIVE TISSUE The different types of connective tissue maintain the form of organs

throughout the body Connective tissues provide a matrix that supports and physically connects

other tissues and cells together in organs

CONNECTIVE TISSUECONNECTIVE TISSUE PROPER it is categorised into two:1) Loose:

includes areolar tissue, reticular tissue, and adipose tissue 

It holds organs in place and attaches epithelial tissue to other underlying tissues

It may be found in tissue sections from almost every part of the body

2) DENSE: also called dense fibrous tissue  is a type of connective tissue with

fibers as its main matrix element forms strong, rope-like structures such

as tendons and ligament

FLUID CONNECTIVE TISSUEIt is categorised into two:

1) BLOOD Blood is considered a connective tissue for

two basic reasons: (1) embryologically, it has the same origin (mesodermal) as do the other connective tissue types and (2) blood connects the body systems

The cell found in greatest abundance in blood is the erythrocyte, responsible for transporting oxygen to body tissues

2) LYMPH Lymph is a clear fluid that is similar to

plasma but contains less protein It flows through lymphatic vessels

throughout the body and includes chemicals and cells whose composition varies according to location within the body.

SUPPORTING CONNECTIVE TISSUEIt is categorised into two:

CONNECTIVE TISSUE

1) CARTILAJE Cartilage is a resilient and

smooth elastic tissue, covering and protecting the ends of the long bones at joints, and is a structural component of the rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs, and many more other body components

 It is not as hard and rigid as bone, but it is stiffer and less flexible than muscle

2) BONE Bone tissue is the major

structural and supportive connective tissue of the body

Bone tissue forms the rigid part of the bones that make up the skeleton.

Supports muscles, organs, and soft tissues.

It is formed by cells, called osteoblasts

MUSCLE TISSUE Muscle tissue is a soft tissue that composes muscles in animal

bodies, and gives rise to muscles' ability to contract  It is formed during embryonic development through a process

known as myogenesis Muscle tissue varies with function and location in the body

MUSCLE TISSUESMOOTH MUSCLE

Smooth muscle is an involuntary non-striated muscle

Smooth muscle is found within the walls of blood vessels

 Smooth muscle is also found in lymphatic vessels, the urinary bladder, uterus, male and female reproductive tracts, gastrointestinal tract, respiratory tract, the ciliary muscle, and iris of the eye

SKELETAL MUSCLE It is a form of striated muscle

tissue which is under the voluntary control of the somatic nervous system

Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons

Muscle fibres, or muscle cells, are formed from the fusion of developmental myoblasts in a process known as myogenesis

MUSCLE TISSUECARDIAC MUSCLE

Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium

These three types of muscle all form in the process of myogenesis

The myocardium is the muscle tissue of the heart, and forms a thick middle layer between the outer epicardium layer and the inner endocardium layer.

Cardiac muscle cells, unlike most other tissues in the body, rely on an available blood and electrical supply to deliver oxygen and nutrients and remove waste products such as carbon dioxide

NERVOUS TISSUE

Nervous tissue or nerve tissue is the main tissue component of the two parts of the nervous system; the brain and spinal cord of the central nervous system (CNS), and the branching peripheral nerves of the peripheral nervous system (PNS), which regulates and controls bodily functions and activity

The function of nervous tissue is to form the communication network of the nervous system by conducting electric signals across tissue

 It is composed of neurons, or nerve cells, which receive and transmit impulses

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