Introduction of anatomy

CELL

1.INTRODUCTION:-

            Cell it is structural & functional unit of the Body.

2.PARTS OF THE CELL:-

1.      Cell membrane.               2.  Nucleous.

3.    Mitochondria.                   4.  Cytoplasm

5.    Golgi Apparatus.              6.  Endoplasmic Reticulumn.

 7.   Ribosomes                        8. Lysozome.

1.      CYTOPLASM: it is a jelly fluid filled inside the cell structure .

It contains of various structures called Organelles.

1.      Mitochondria:-  it is a small granular structure containing enzyms C  extract energy from nutrients & O₂ in the form of ATP (Adenosin triphosphate )

It helps for  cellular activity.

Mitochondria also called it has ‘Power House of the Cell”

2.      Endoplasmic Reticulum:-

It is a complicated network of tubules and vesicles connected with  the nucleous & the cell membrane

3.      Ribosomes:-

Granules which contain RNA , it responsible for protein synthesis in the cell.

4.      Lysosomes:-

Its contain enzynes that digest & remove particles which  are useless, (or) may be harmfull to the cell. Lysosome also called it has “Suicidal Bags”

 4.Endoplasmic Reticulum:- it is a complicated network of tubules & vesicles connected with  the nucleous & the cell membrane.

It transfer substances from one part of the cell to another & surface are ribosomes.

5.      Goligibody:-

This consists of a series of time vesicles & is especially prominent in secretory cell.

       6.  Centrosome:- it lies close to the nucleous & its mode of 2 centrioles.

It plays a major role in initiating cell divison.

7.Cell membrane:-

It’s a outer part of the body.

It helps to pass the substance into the cell which are necessary.

It prevents the harmfull substances entry into the cell.

Nucleous:-

            It is a major  part of the cell.

 it consist of more compact mass of protoplasm separted from the Cytoplasm by the nuclear membrane.

·         Nuclear  membrane allows substances to escape from the nucleous into the cytoplasm (or) substances to pass into it.

·         Nucleous controls the all activities in the cell its contain special type of portion called nucleoprotein.

·         It controls both chemical reactions occur in the cell & reproduction cell.

·         Chromatin :-it’s a state of non dividing nucleous & appear as a marks of darkly staining material called chromatin.

·         Human cells contains 23 pairs of chromosomes I,e, 46 chromosomes.

Each chromosome consists a chain of smaller units rather like a  string of beds

These small units are called Genes.

·         Each Gene has a Very specific location on a particular chromosome.

                                    FUNCTIONS OF CELL:

·         Irritability: cells has the ability to detect & respond to changes in its environment.

·         Nutrition:- it helps to provide energy & heat growth & response helps for absorption of fluids & dissolved  substances directly through the cell membrane.

·         Respiration: it has the ability to use oxygen combined with  food substance to form co₂ & H₂O  while releasing energy for intracellular activity.

·         Excretion:- it helps for discharge unused & waste materials  through the cell membrane

·         Growth & Reproduction:- its helps for cell growth ie size & Reproduces by dividing into 2 cells.

·         It helps for movement.

·         It produce the enzymes.

                  CELL DIVISION

Introduction:

Cells are the smallest functional units of the body. They are grouped together to from tissues, each of which has a specialized function.(eg) blood, muscle ,bone. Different tissues are grouped together to from organs, e.g heart, stomach, brain. Organs are grouped together to form systems. Each of which performs a particular function that maintains homeostasis and contributed to the health of the individual.

Cell division:

Most body divide by mitosis a process that results in two new genetically identical daughter cells. Formation of gametes ova & Spermatozoa takes play by meiosis and four daughter cells are genetically different from the parent cell and each other.

       The period between cell division is known as interphase towards the end of interphase. The chromation replicates and becomes tightly coiled forming double chromosomes called chromatids in preparation for cell division in human cells there are 46 chromosomes. The two chromotids of each chromosome are joined at the centromere.

Mitosis:

This is a continuous process involving four distinct stages seen by eight micros copy.

Prophase:

During the stage the chromotids become visible within the nucleolus and the mitotic apparatus appears. This consist of two centrioles separated by the micro tubules mitotic spindle which is formed from microtubules the centrisotes migrate one to each end of the cell & the nuclear envelope disappears.

Metaphase:

The chromatids align on the centre of the spinde, attached by this centromere.

Anaphase:

  The centromere spererte and one of each pair of sister chromaticls migrates to each pole of the spindle as the microtubules that form mitotic spindle contract.

Telophase:

     

The mitotic apparatus disappears the chromosomes uncoil and the nuclease envelope reform. Telophase.the cytoplasm and plasma membrance divide in half forming two identical daughter cells. The orangelles of daughter cells are imcomplete at the end of cell division but they develop as the cell matures during interphase.


                         

  

TISSUES

Definition: the group of cells called  it has Tissue

There are large number of cells which are present in our body in the form of tissue.

Tissue can be classified into 4 types according to the size, shape & function of these cells/.

1.      EPITHELIAL TISSUE

2.      CONNECTIVE TISSUE

3.      MUSCLE TISSUE

4.      NERVOUS TISSUE.

EPITHELIAL TISSUES: these are group of tissues is found covering the body & living cavities hollow organs & tubes.

It is also found in glands.

Functions of epithelial structures:-

1.      Protection of unerling structures.

Eg: dehydration chemical & mechanical Damage

2.      Secretion:

3.      Absorption

·         Epithelical cells are very closely packed & the intercellular substance called the matrix  is minimal.

·         The cells usually lie on a basement memberane

·         Epithetical tissue classified into

·         1. Simple-A single layer of cells

·         Stratified- several layers o cells.

SIMPLE EPITHELIUM:

Simple epithelium consists of a single layer of identical cells & devided int four types.

It is usually found on absorptive (or) secretory surfaces  where the single layer enhance these proceses & not usually on surfaces subject to stress.

The types are named according to the shape of thecells & functions

The more active the tissue, the taller the celles.

SQUAMOUS (PAVEMENT) EPITHELIUM:-

This is composed of a single layer of flattend cells.

The cells  fit closely together like flat stones forming a thin & very smooth membrane.

Diffusion takes place freely through this thin, smooth living of the following structure,

Heart

Blood vessels                         

Lymph vessels                         where it is known as ENDOTHELIUM

Alveoli of the lungs.

CUBOIDAL (CUBICAL  EPITHELIUM :-

-          These are CUBE shaped cells fitting closely together lying on a basement membrane

-          It forms the kidney tubles & is found in some glands.

-          cuboidal epithelium is actively involed in secretion, absorption & excertion.

COLUMNAR EPITHELIUM:-

-          This is formed be a single layer of cells rectangular in shape on a basement membrane.

-          It is found lining the organs of the alimentary tract & consist of a mixtures of cells some absorb the product of digestion & others secrets “ MUCUS”

-          MUCUS: it is a thick sticky substance secrated by specialized columnar cells called “ goblet cells”

CILIATED EPITHELIUM:-

-          Cilia are microscopic hair like processes on the free surface of columner epithelial cells lining certain passage ways,

Eg: uterine tubes & airways where their wave- like motion propels materials one-way.

The uterine tubes the cilia propels ova towards uterus & in the respiratory passages they propel muscus towards the through.

STRATIFIED EPITHELIA :-

-          Stratified epithelia consist of several layers of cells of various shapes:

-          The supertifical layers grow up from below.

-          Basement membranes are usually absent

-          The main function of stratified epithelium is to protect underlying structures from mechanical wear & tear.

It is divided into 2 types:

-          Stratified squamous

-          Transitional epithelium.

STRATIFIED SQUAMOUS EPITHELIUM:-

-          It is composed of a number of  layer of cells of different shapes representing newly formed & mature cells.

-          In the deepest layers the cells are mainly columnar & as they grow towards the surface they become flattened & are then shed.

NON-KERATINISED STRATIFIED EPITHELIUM”

-          It is found an wet surfaces subject to wear & tear but are protected from drying.

Eg:- the conjuctives of the eyes.

The lining of the month.

The pharynx, the oesphages & the vagina.

KERATINISED STRATIFIED EPITHELIUM:-

-          This is found on dry sufaces  subject to wear and tear I,e skin hair & nails.

-          The surface layer consists of dead epithelial  cells that contain the protein  called keratin.

-          This forms a though relatively water proof  protective layer that prevents drying of the live cells undermeath.

-          The surface layer of skin is rubbed of and replaced from below.

TRANSITIONAL EPITHELIUM:-

This is composed of several layers of pear shapes cells.

It is found living the urinary bladder & allows  for  stretching as the bladder fills.

STRATIFIED COLUMNAR EPITHELIUM :

 It provides protection along portion of the respiratory tract,GIT,Reproductive tracts.

                                       CONNECTIVE TISSUE

Connective tissue/supporting tissue:

It connects between to tissues or organs hence we called it has connective tissue.

These are made up of cells which are found single or in groups of 2 or more,space between the cells is called Matrix. Which is filled with different substances.

Example

1.BONES  & salts of calcium and magnesium with carbonate and phosphate,it helps to make bone rigid and hard.

2.BLOOD  &  plasma

 It helps to make blood fluid.

FUNCTIONS:

1.it provide support and protect the internal organs

2.it helps for transportation of materials

3.it stores energy sources , ex:fats.

4.active defence part.

CLASSIFICATION :-

a.connective tissue proper

b.supporting connective tissue or skeleton tissue

c.fluid connective tissue.

A.CONNECTIVE TISSUE PROPER:-

it refers to connective tissues which with many types of cells and fibers sorrunded by matrix.

Cells of connective tissue :-

Connective tissue cells are found in all organs except blood.

Example :

 Fibroblasts

Fatcells

Macrophages

Leukocytes

Plasma cells

Mast cells.

FIBROBLASTS :-

Fibroblasts are large flat cells with irregular process.

Fibroblasts produce collagen and elastic fibres and a matrix of extracellular material hence called it has reticulin fibres, majorly found in liver, lymphoid tissue and tissue repair (wound healing).

FAT CELLS:-

Fat cells also called it has  Adipocytes.

It mostly occur in singly or in groups of many connective tissue in specially abandent adipose tissue.

It vary in size and shape according to the amount of fat.

MACROPHAGES :-

These are irregular shaped cells with granules in the cytoplasm.

Some are fixed and some attached to the connective tissue fibers.

It plays a important role during defence mechanism i`e helps to digesting cell debris,bacteria and other foreign bodies.

Example :-

1.monocytes in blood

2.phagocytes in alveoli of the lungs

3.kupffer cell in liver sinusoids

Fibroblasts in lymph and spleen

Microglial cells in the brain.

LEUKOCYTES:-(WHITE BLOOD CELL)

It normally found in small numbers but in healthy connective tissue.

It plays a very important role during tissue diffence.

PLASMA CELLS:-

It develops from B-lymphocytes a type of WBC.

They synthesis and secrete specific  defensive antibodies into the blood and tissue.

MAST CELLS :-

These cells are similar to basophil leukocytes

It founds in loose connective tissue.

Example:- liver and spleen blood vessels.

It produce granules it contains heparin,histamine.

It stimulates the secretion of gastric juice and is associated with the development of allergies and hypersensitivity

Heparin prevents the co-agulation of blood.

LOOSE (AREOLAR) CONNECTIVE TISSUE:-

This is the most generalized type of connective tissue

The matrix is semisolid with many fibroblasts and some fat cells.

Mast cells and macrophages widely separated by elastic and collagen fibers.

It is found in almost every part of the body and its provides elasticity and tensile strength.

Example :-

a.under the skin

b.between muscles

c.supporting blood vessels and nerves

d.in the alimentary canal

e.in glands supporting secretory cells. 

      

DENSE CONNECTIVE TISSUE

This contains more fibres and fewer cells than loose connective tissue.

FIBROUS TISSUE:

This is a dense fibrous connective tissue made up mainly of closely packed bundles of collagen fibres, with very little matrix,and very few cells lying in rows between the bundles of fibres and developed from fibroblasts.

1.       Forming ligaments, which bind bones together.

2.       As an outer protective covering for bone,called PERIOSTEUM

3.       As an outer protective covering of some organs, eg,the kidneys,lymphnodes and the brain

4.       Forming muscle sheaths called MUSCLE FASCIA,which extend beyond the muscle to become the tendon that attaches the muscle to bone.

ELASTIC TISSUES :

Elastic tissue is capable of considerable extension and recoil.

There are few cells and the matrix consists mainly of masses of elastic fibres secreted by fibroblasts.

It is found in organs where stretching or alteration of shape is required ,e.g in large blood vessel walls,the trachea and bronchi, and the lungs.

LYMPHOID TISSUE

This tissue ,also known as reticular tissue,has a semisolid matrix with fine branching reticullin fibres.

It contains reticular cells and white blood cells (monocytes and lymphocytes).

Lymphoid tissue is found in lymph nodes  and all organs of the  lymphatic system.


                                     

LOOSE (AREOLAR) CONNECTIVE TISSUE .

This is the most generalized type of connective tissue.

The matrix is semisolid with many fibroblasts and some fat cells.

Mast cells and macrophages widely separated by elastic and collagen fibres.

It is found in almost every part of the body and its provide elasticity and tensile strength.

Example :

Under the skin .

Between muscles

Supporting blood vessels and nerves

In the alimentary canal

In glands supporting secretory cells.

ADIPOSE TISSUE 

Adipose tissue consists of fat cells(adipocytes),containing large fat globules,in a matrix of areolar tissue.

There are 2 types of adipose tissue.

1.white adipose tissue

2.brown adipose tissue

WHITE ADIPOSE TISSUE :

This makes upto 20 to 25% of body weight in well developed adults.

It is found supporting the kidneys and the eyes,between muscle fibres and under the skin,where it acts as thermal insulator.

BROWN ADIPOSE TISSUE:

It is presents relatively small quantities in  the newborn.

The incidence of brown fat,through present in human embryos, is rare in adults.

It is belived that embryonioc brown fat is gradually converted  into the white variety.

It produces less energy and considerably more heat than other fat.

      

MEMBRANES:

It is a pliable sheet like structure acting as a boundary,lining or partition in an organism.

 Types of membranes:

1.       Epithelial membranes.

2.       Mucous membrane .

3.       Serous membrane.

4.       Synovial membrane.

EPITHELIAL MEMBRANES:-

These membranes are sheets of epithelial tissue and supporting connective tissue that cover or line many internal structures or cavities.

MUCUS MEMBRANES:-

 MUCOSA.

The membrane surface consists of epithelial cells some of which produce a secretion called MUCUS.

Mucus it’s a slimy tenacious fluid and moist slippery surface.

Mucus protects the lining membrane from drying and mechanical and chemical injury.

In respiratory tract traps inhaled foreign particles,preventing them from entering the alveoli of the lungs.

SEROUS MEMBRANE:-

Serous membranes or serosa secrete serous watery fluid.

It consist of a double layer of loose areolar connective tissue lined by simple squamous epithelium.

It contains 2 layers.

1)      Parietal layer lines cavity.

2)      Visceral layer surrounds organs.

2 layers separated by serous fluid.

Cites of serous membrane:-

1)      Pleura lining the thoracic cavity surrounding the lungs.

2)      Pericardium lining the pericardial cavity surrounding the heart.

3)      Peritoneum lining the abdominal cavity surrounding the abdominal cavity.

The serous fluid between the visceral and parietal layers enables an organ to glide freely within the cavity without being damaged by friction between adjacent organs.

The heart changes its shape and size during each beat and friction.

SYNOVIAL MEMBRANE :-

This membrane lines the cavities of movable joints and surrounds tendons that could be injured by rubbing against bones.

Example : over the wrist joint.

Synovial membranes secretes clear, sticky,oily.synovial fluid, which lubricates and nourishes the joints.

     

                GLANDS

Glands are groups of epithelial cells that produce specialised  secretions.

Glands that discharge their secretion onto the epithelial surface of hollow organs,either directly or through a duct,are called EXOCRINE GLANDS.

Secretions of exocrine glands include mucus,saliva,digestive juices and earwax.

Exocrine glands vary considerably in size,shape and complexity.

Other glands discharge their secretions into blood and lymph,these are called ENDOCRINE GLANDS (Ductless gland) and their secretions are hormones.

Functions

1.keeps a surface moist.

2. provides lubricant for frictional surfaces.

3. enzymes for digestion

4. hormones for control and regulation of body functions


        CAVITIES OF THE BODY.

Cavities of the body classified into

1.cranial cavity

2.thoracic cavity

3.abdominal cavity

4.pelvic cavity.

              CRANIAL CAVITY.

The cranial cavity contains the brain,and its boundaries are formed by the bones of the skull.

Anteriorly:frontal bone.

Laterally:2 Temporal bones.

Posteriorly:1 occipital bone.

Superiorly:2 parietal bones.

Inferiorly:1 sphenoid and 1 ethmoid bone and parts of the frontal,temporal and occipital bone.

      THORACIC CAVITY:

This cavity is situated in the upper part of the trunk.

Its boundaries are formed by a bony frame work and supporting muscles.

Antgeriorly: the sternum and costal cartilages of the ribs.

Laterally:12 pairs of ribs and the intercostals muscles.

Posteriorly: the thoracic vertebrae.

Superiorly:the structures forming from thr root of the neck.

Inferiorly:the diaphragm, a dome shaped muscle.

Thoracic cavity contains

1.the trachea,2 bronchi, 2 lungs.

2.the heart,aorta,superior vene cava, numerous other blood vessels.

3.the oesophagus.

4.lymph vessels and lymph nodes.

5. nerves

6. the mediastenium is the name given to the space between the lungs including the structures found there ,such as the heart,oesophagus and blood vessels.

         ABDOMINAL CAVITY:

This is the largest cavity in the body and is in oval shape.

It is situated in the main part of the trunk and its boundaries.

Superiorly: the diaphragm, which separates it from the thoracic cavity.

Anteriorly:the muscles forming the anterior abdominal wall.

Posteriorly :the lumbar vertebrae and muscles forming the posterior abdominal wall.

Laterally:the lower ribs and parts of the muscles of the abdominal wall.

Inferiorly : it is continous with the pelvic cavity.

The abdominal  cavity is divided  into the nine regions.

This facilitates the description of the portions of the organs and structures.

Other structures include

1.the spleen

2. 2kidneys and the upper part of the ureters

3.2Adrenal glands.

4.Blood vessels, lymph vessels, nerves cavities of the body

5.lymph nodes.

            PELVIC CAVITY.

The pelvic cavity is roughly funnel shaped and extends from the lower end of the abdominal cavity.

The boundaries are

Superiorly : it is contains with the abdominal cavity.

Anteriorly :the pubic bones.

Posteriorly :the Sacrum and coccyx.

Laterally :the innominate bones.

Inferiorly : the muscles of the pelvic floor.

Pelvic cavity contains,

The pelvic cavity contains the following structures.

1.sigmoid colon ,rectum and anus.

2.some loops of the small intestine.

3.urinary bladder ,lower parts of the ureters and the urethra .

In female: reproductive organs.

The uterus,uterine tubes,ovaries and vagina.

Male reproductive organs:

Prostate gland,seminal vesicles,spermatic cords, deferent ducts (vas deferens), ejaculatory ducts and the urethra.