the light microscope
the microscope produces an enlarged image of an object to be examined , the image becomes magnified as it is transmitted through the lenses , this magnification depends on the power of lenses used .the light microscope is only instrument available for examining cells in their natural state .
magnification power = magnification power × magnification power
of microscope of eye piece of objective lens
part of light microscope:
1. arm
2. eye piece
3. body tube
4. revolving nosepiece
5. low power objective lens of 10×
6. high power objective lens of 40× or 100×
7. oil immersion objective lens of 100×
8. stage
9. clips
10. mechanical stage
11. knobs of mechanical stage
12. condenser
13. coarse adjustment
14. fine adjustment
15. pillar
16. foot
17. lamp
18. switch
lab.2:-
the animal cell
the cell is the structural and functional unit of all living organisms . it is composed of several compartment which include organelles and complex compound . the organelles , means plasma membrane bounded structures , where as complex compounds include several type of macromolecules , sugar , proteins, lipids ,……
_ plasma membrane: separate a cell from its environment , it is a selective permeable membrane composed of bilayer phospholipids with proteins .
mitochondria : it is the site for oxidative generation of energy (atp) .
golgi apparatus : it is the organelles responsible for the production of proteins in out side the cells
endoplasmic reticulum: tow types rough (r.e.r.) which is the site for the synthesis of protein , smooth(s.e.r) site for lipid synthesis.
nucleus:- surrounded by nuclear membrane and contain set of chromosome (genetic material) and control all the cellular activities .
cell cycle
g 1 phase: growth phase
s phase: dna synthesis phase
g 2 phase: growth of cell organelles
m phase: mitosis
c phase: cytokinesis
the shape of animal cells
there are several shape of animal cells:
1. star –shaped such as multipolar nerver cell.
2. cubic – shaped such as simple cuboidal epithelial tissue in the kidney tubules .
3. oval – shaped such (r.b.c.) red blood cell of frog .
4. polygonal – shaped as squamous cell in simple squamous epithelial tissue in lung or inside walls of bloods vessels .
5. biconcave disc – shaped such as erythrocytes (r.b.c.) of human blood .
lab.3:-
epithelial tissue
an epithelium is a sheet like layer of cells with close cell - to- cell contact that covers surfaces and lines cavities . epithelia also often contain glandular cells that function is fluid secretion . where epithelium lines the inner surface of the heart , blood vessels, and lymphatic vessels it is given a special name (endothelium) .
the chief function of an epithelium is protection , but the cells are also variously specialized for secretion , excretion ,absorption , lubrication , and sensory perception .
epithelial tissue may be classified according to the number of layers of cell (simple and stratified) or according to the shape of the cells on the free surface ( squamous , cuboidal , or columnar) .
simple epithelium tissue
simple epithelium is made up of single layer of epithelial cells. it is found where there is not much wear and tear or where diffusion or absorption occurs through a membrane.
1. simple squamous epithelium tissue :composed thin flat cells with round or oval nuclei, found inside walls of blood vessesls (endothelium),the body cavity,and the lungs.
2. simple cuboidal epithelium tissue : lines small ducts and tubules, such as kidney tubules, salivary glands ,and mucous glands.
3. simple columnar epithelium tissue: is found on highly absorptive surface such as lining of the small intestinal, and on secretive surface such as the lining of the stomach.
4. pseudo stratified columnar epithelium tissue: pseudo stratified columnar cells are actually simple epithelium with all the cells resting on a basement membrane. the cells have the appearance of stratified epithelium because they are not all the same height and their nuclei are located at different levels, some cell don’t reach the surface ,pseudo stratified columnar tissue line the trachea and bronchi.
stratified epithelium tissue
composed of two or more layers of cells, it is found where surface cells are being continually sloughed off, it is not adapted for absorption or secretion.
1. stratified squamous epithelium tissue: consist of several layers of cells. found in areas that withstand abrasion like the lining of the mouth ,pharynx ,esophagus anal canal, and vagina.
2. transitional epithelium tissue: is a form of stratified epithelium tissue confined to the urinary tract bladder, when relaxed the epithelium appears to be four or five cells thick, when stretched ,it appears only tow or three cells thick ,with the surface cells flattened.
lab.4
the connective tissue
the connective tissue are tissue of mesodermal origin that provide structural and metabolic support for the body . despite the diversity of connective tissue , all are composed of cells and extra cellular fibers embedded in a structureless ground substance (also called matrix) . both the fibers and the ground substance are secreted by the cells.
classification of connective tissues:-
general connective tissue or proper connective tissue:-
i .) dense connective tissue:- distinguished by adundance of fibers in corporated within the matrix:-
a- dense irregular connective tissue:- unarranged fibers such as dermis.
b- dense regular connective tissue :- fibers arranged , white fibers connective tissue (tondon) that join muscle to bone and elastic connective tissue (ligaments)that join bone to bone.
ii .) loose connective tissue:- classified to :-
1- mesenchyme connective tissue
2- areolar connective tissue:- most widespread of all the connective tissue. it is found fastening down the skin it consist of a clear jelly like matrix, various cells ,and all three types of fibers(white, elastic, reticular fibers).
3- mucoid connective tissue
4- adipose connective tissue: specialized for the storage of lipids each cell contains a single lipid dropinglet. the cytoplasm and nucleus have been pushed to one side of the cell by the lipid dropingt.
5- reticular connective tissue.
lab.5
special connective tissue:-
a-) skeletal connective tissue: special type of connective tissue, composed of cells and matrix, the matrix consist of ground substance containing fibers ,cartilage and bone are different chemically as well as structurally.
1- cartilage :it forms the skeleton of early mammalian fetuses but it is gradually replaced in the growing individual by bone, and only remnants of it are encountered in the skeleton after maturity. at that time cartilage is one of the least prevalent constituents of the human body.
· hyaline cartilage :the most common form of cartilage it is found on the ends of long bones and in the nose, trachea and other places, its ground substance is firm but flexible scattered through it lacunae , little cavities each containing at least one cell. the cells secret the ground substance and some collagen fibers.
· fibro cartilage: found in the intervertebral discs , the ground substance contains many inelastic fibers.
· elastic cartilage: found in places such as the external ear , epiglottis , and larynx contains many elastic fibers.
2- compact bone : is the most specialized of supporting connective tissue , it not only supports ,but it also protects vital organs by means of bony frameworks , and it forms the red blood cells and most of white blood cell.
bone matrix is heavily infiltrated with calcium and phosphate salts.
a long bone such as the femur or humerus ,consist of a shaft of compact bone surroundidng a bone marrow cavity .
compact bone is made up of series of oseons ,each one built around a narrow canal containing blood vessels , the bone-forming cells , osteoblasts, become arranged in the matrix around the blood vessels in layers called lamellae .each osteoblasts occupies space called a lacuna .the cell have branching , thus forming tiny channels , called canaliculi through which nourishment can reach the cell from the blood supply.
b-) vascular connective tissue:
blood and lymph are often considered to be connective tissue having a variety of cells types (corpuscles) suspended in fluid matrix (plasma) and flowing within a system of blood vessels .vascular tissue transports nutritive substances, oxygen, and hormones to the tissues and carries away wasts.the cells in blood include erythrocytes, leukocytes and blood platelets.
1. )erythrocytes(red corpuscles) or r.b.c.(red blood cell):-
in the human and other mammals erythrocytes are round,biconcave discs that don’t have nuclei. they average about (7µm ) in diameter but are very thin .oval-shaped erythrocytes with large granular nuclei are found in most other vertebrates.vertebrate red corpuscles are packed with the respiratory pigment hemoglobin ,which function to transport oxygen and carbon dioxide between the lungs and the body tissues.
2. ) leukocytes(white corpuscles) or w.b.c. (white blood cell):-
there are several types of leukocyte in vertebrate blood ,all with large ,darkly,staining nuclei,in human blood they are larger than the red cells in other vertebrate they are smaller .by means of their amoeboid movement they can pass through capillary walls and surround ingest foreign particles and invading organisms(a process called phagocytosis).
monocytes and neutrophil are the most active phagocytes, lumphocytes play a key role in all immuno responses. lwukocytes perform their protective functions outside the blood vessels in connective tissue.the pus that form in and around an infection consists largely of dead white blood cells.
3.) blood platelets:
platelets are disc-shaped ,tiny (2 to3 µm in diameter) ,very fragile, clot promoting bodies found only in mammalian blood.
lab.6
muscle tissue
1. smooth muscle : smooth muscle is also called nonstriated , visceral , or involuntary muscle. it structure is the simplest of the three types of muscle.it is found where slow sustained contractions needed. such as in the digestive tract .it is involuntary action under the unconscious control of the autonomic never system.
smooth muscle cells are long and spindle shaped through rarely longer than 5.0mm .the nucleus is located in the middle , or thickest part of the cell , and the ends of the fober diminish gradually to a fine point .muscle fiber are composed of bundles of slender myofibrils, which in smooth muscle don’t have cross striations , as in skeletal and cardiac muscle .
2. skeletal muscle : skeletal muscle is also known as striated or voluntary muscle. voluntary because it is under conscious cerebral control. it makes up the bulk of the muscular system .skeletal muscle contracts more rapidly than smooth muscle , but it fatigues more easily and is not capable of sustained contraction.
a skeletal muscle fiber is long (1 to 40mm) and cylindric and has blunts ends .each fiber is made up of many myofibrils , all enclosed in a tough membrane called the sarcolemma .each fiber has a number of nuclei located just beneath the sarcolemma. the myofibrils bear light and dark bonds and are so arranged.
the muscle fiber are grouped into bundles are grouped into skeletal muscle .fiber , bundles , and muscles are embedded in connective tissue fascia. the connective tissue of the muscle merges with the fibrous sheet or tendon that holds the muscle . skeletal muscle are richly supplied with blood vessels and nerves.
3. cardiac muscle : is much like skeletal muscle in structure in that it is striated , but it functions more like smooth muscle .it is involuntary muscle well adapted for rhythmic contraction .the fibers are arranged in branching columns interconnected in fine meshwork.the myofibrils are transversely striated as in skeletal muscle , but the nuclei are centrally located , as in smooth muscle .
lab.7
nervous tissue
nerve cell or neuron :- can be classified according to the number of their extensions in to :-
1. unipolar nerve cell :- it has a single extension called "the axon" .this type of nerve cell observed in the early stages of embryonic development.
2. bipolar nerve cell:- it has tow extentions "the axon" and "the dendrite" . this type of nerve cells founf in the retina and olfactory epithelium .
3. pseudounipolar nerve cell:- it has a rounded cell body with a clear central nucleus and a single , large extension which branched in to tow extensions the axon and the dendrite.
4. multipolar nerve cell : there are many extensions extend from the cell body in this type of nerve cell .it has many shapes(star, pyramidal, conoid).the nucleus is clear, large , with an observable "nissl bodies" .
nerve fibers:- there are two types of nerve fibers:-
1. myelinated nerve fibers :- when we examine this type of nerve fibers we will see the axon surrounded by the myeline sheath and along the nerve fiber there are many narrow regions(unsurrounded by the myelin sheath)called "nodes of ranvier" .
2. unmyelinated nerve fibers:- this type of nerve fibers missing the myelin sheath.
spinal cord :- the transverse section of the spinal cord appear rounded or ovoid. the dorsal side divided in to two halve ,right and left by" the dorsal median septum" also the ventral side divided by the "ventral median fissure" .
the center of the spinal cord appears as "h" litter ,this region represent the gray matter which has a dark color ,while the white matter surrounding the gray matter and has a light color.the spinal cord surrounded completely by a fibrous envelop called the "pia mater" .
lab.8
subkingdom and phylum
protozoa
the protozoa (first animals) are the simplest and most primitive animals some of them are even considered as plants . they are mostly microscopic but a few attain a considerable size . they live either singly or in colonies , in sea, fresh water , and damp soil some are parasitic . they are usually defined as ،، unicellular’ ’ animals , but actually a protozoon is not a loose cell moving about and equivalent to one of the cell of the more complex metazoa . it is a complex organism whose protoplasm generally displays but little differentiation , performing , are ،، acellular’’ rather than unicellular , that is , their body is not partitioned into cells . their unique structure necessitates including them in a separate subkingdom , which
comprises only one phylum bearing the same name _protozoa . they are classified into four classes on the basis of the structures they are possess for locomotion : sarcodina (or rhizopoda) , mastigophora (or flagellata) , sporozoa and ciliophora .
a. class sarcodina
the class sarcodina includes forms called pseudopodia . although the gametes and young forms may move by flagella .
1.amoeba
amoeba lives in freshwater ponds and the backwater of rivers among decaying vegetable matter in which bacteria abound , securing its food from these bacteria and other microscopic organisms . while still some other are parasitic . amoeba moves by pseudopodia . reproduces asexually by binary fission . and under unfavourable conditions it encysts.
* amoeba is quite irregular in shape constantly with the formation and withdrawal of broad irregular processes called –pseudopodia- .the animal usually progresses in the direction of its pseudopodia (amoeboid movement) which also are used in searching for and capturing food .
* body .in the form of a translucent mass of protoplasm distinguishable into an outer thin clear –ectoplasm- (the analogue of the skin) and an inner granular more fluid mass, the –endoplasm-.
* in the endoplasm distinguish -food vacuoles- in which micro-organic on which amoeba feeds are found and digested nucleus, plate-like and more refractive than the rest of the endoplasm ,with an endosome and can better be seen in a stained preparation contractile vacuole ,one sometimes more.as a clear spherical structure filled with a clear fluid which bursts out at regular intervals and reforms, this ridding off the animal from excess water(osmo
b. class mastigophora
this class includes forms which move by flagella, either one or more.and have a definite form because of the presence of a firm pellicle(although some may develop pseudopodia) .two sub-classes are recognized according to the method of feeding :phytomastigina usually feed holophytically ,and zoomastigina which are either holozoic or parasitic.
1.euglena
euglena is one of the phytomastigina which appears in ponds and stagnant water in enormous numbers ,producing the green colcuration of the water. euglena moves by a whip-like process of the ectoplasm called the flagellum and by the contraction of its body(euglenoid movement). it is holophytic ,although it is able to live as a saprophyte. it reproduces asexually by long-itudinal binary fission and is able to form a cyst.
general body form ,fusuform ,pointed posteriorly, with a long delicate flagellum coming out from the blunt anterior end. movement is by twisting the body spirally ,by its contraction and expansion in the direction of movement ,and by the flagellum beating right and left.
body differentiated into an outer thin ectoplasm toughened by an outer firm pellicle, and an inner much larger endoplasm .this contains numerous chloroplast .green bodies containing cloropgyll (aids in carbohydrate synthesis),either scattered singly or connected together
paramylum granules which contain a reserve of a starch-like carbohydrate nucleus ,a spherical body with an endosome and a stigma or eye-spot at the anterior end (sensitive to light ).
gullet ,through which the flagellum passes out reservoir at base of gullet base of flagellum split into two ,each division connected to a tiny basal granule or blepharoplast embedded in the ectoplasm (the two control movement of flagellum ) contractile vacuole formed of a main vacuole surrounded by a circlet of small vacuoles which discharged into the main and this into the reservoir.
d- class ciliophora
there are the most specialized protozoa .they move by means of cilia at least at some stage of development and have a definite body form .most of them are free-living but some are parasitic.
1.paramecium
several species of paramecium occur in great abundance in freshwater ponds ,where decaying organic matter is found ,feeding on bacteria and this matter. p. bursaria contains zoochlorellae which help in synthetising food and thus can withstand starvation for a long time . paramecia reproduce by binary fission and by conjugation in which two individuals conjugate and after complex nuclear divisions give rise to 8 new individuals some of them ,full of vigour, will give rise to better generations.
ectoplasm and endoplasm ,food vacuoles, 2 contractile vacuoles , oral grove on the right side of the anterior edge. it leads to a channel-like vestibule that extends diagonally across the animal to the left posterior half and ends with the mouth .this opens into a small gullet which is a mere cleft in the endoplasm .note the numerous cilia covering the whole surface of the body.they resemble flagella but are much shorter ,and grater in number. the cilia in the vestibule are somewhat longer ,denser arranged in rows and almost adhere sidewise so as to form something like a membrane whose wave-like undulations (so erroneously described as an undulating membrane) help to propel food into the gullet.
in the ectoplasm distinguish 4 zones .an outer thin .but firm( pellicle), which has a characteristic surface pattern of hexagonal depressions from each of which a cilium comes out a second zone contains the basal granules of the cilia and fine contractile myonemes connecting these granules together athird one contains numerous spindle-shape bodies perpendicular to the surface and called the trichosysts (defensive in function) and lastly a thichk zone , innermost ,which contains the two contractile vacuoles , one anterior and one posterior . watch the vacuoles and notice how each is increased in size by the flowing into it of a number of radiating narrow canals or vacuoles that arise in the surrounding endoplasm . this process takes place at short regular intervals , and the vacuoles are said to pulsate . count the number of times the vacuoles distends and discharges its contents on to the surface of the body per minute .
- in the stained preparation identify in the endoplasm two nuclei , a large oval mega or macronucleus ( concerned with vegetative functions) and a small micronucleus (concerned with reproduction) situated alongside with the former . also look out for the other above mentioned details .
lab.9
frog body :-
as in other higher vertebrates ,the frog body may be divided into a head ,a short neck ,and a trunk . the flat head contains the brain ,mouth , eyes , ears and nose .a short ,almost rigid neck permits only limited head movement .the stubby trunk forms walls for a single body cavity,the coelom.
man’s internal organs are housed in one of three distinct hollow cavities –the chest,the abdomen,and the pelvis.
there is no such partition in the frog’s coelom.
all the frog’s internal organs-including the heart,the lungs,and all organs of digestion are held in this single hollow space.
the skeleton and muscles
the frog’s body is supported and protected by a bony framework called the skeleton.
the skull is flat ,expect for an expanded area that encases the small brain.only nine vertebrae make up the frog’s backbone ,or vertebral column.the human backbone has 24 vertebrae .the frog has no ribs .the frog does not have a tail .only a spike like bone.
the shoulders and front legs of the frog are somewhat similar to man’s shoulders and arms .the frog has one "forearm" bone,the radioulna . man has two forearm bones ,the radius and the ulna .both frog and man have one "upper arm" bone, the humerus.
the hind legs of the frog are highly specialized for leaping. the single "shinbone" is the tibiofibula .man has two lower leg bones, the tibia and the fibula. in man and in the frog, the femur is the single upper leg(thigh) bone. a third division of the frog’s leg consist of two elongated anklebones, or tarsals. these are the astragalus and the calcaneus. the astragalus corresponds to the human talus. the calcaneus in the human skeleton is the heel bone.
the circulatory system
there are two upper chambers of the heart,the right atrium and the left atrium .the frog heart, however ,has only one lower chamber, a single ventricle. in man ,the lower heart chamber is divided into two compartments, the right ventricle and the left ventricle.
the skin and respiratory system
the frog is covered by a soft ,thin,moist skin composed of two layers, an outer epidermis and an inner dermis.the skin does not merely protect the frog but helps in respiration .the frog does not breath through its skin alone .adult frogs have paired ,simple,saclike lungs.
the digestive and excretory system
the frog’s mouth is where digestion begins. it is equipped with feeble, practically useless teeth. there are present only in the upper jaw. the frog’s tongue is highly specialized. normally, the tip of its tongue is folded backward toward the throat. from this position the frog can flick it out rapidly to grasp any passing prey. to better hold this prey, the tongue is sticky.
food passes from the frog’s mouth into the stomach by way of the esophagus. from the stomach, the food moves into the small intestine, where most of the digestion occurs. large digestive glands, the liver and the pancreas, are attached to the digestive system by ducts.
lipid wastes from the kidneys travel by way of the ureters to the urinary bladder.solid wastes from the large intestine pass into the cloaca . both liquid and solid waste material leave the body by way of the cloaca and the cloacal vent.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .