SANJEEVANI PUBLIC SCHOOL

NAME - CHETAN SEHGAL

CLASS- IXTH - A5ROLL NO – 7

SUBJECT – SCIENCE

PRESENTATION ON TISSUES

TISSUEINTRODUCTION OF TISSUE

GROUP LEADER NAME – EKTA

MITTAL

WHAT IS TISSUE tissue is a cellular organizational level intermediate between 

cells and a complete organism. a tissue is an ensemble of similar cells and from the same origin, that together carry out a specific function. these are called tissues because of their identical functioning. organs are then formed by the functional grouping together of multiple tissues.

the study of tissue is known as histology or, in connection with disease, histopathology. the classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. in the last couple of decades, developments in electron microscopy, immunofluorescence, and the use of frozen tissue sections have enhanced the detail that can be observed in tissues. with these tools, the classical appearances of tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis.

CONECTIVE TISSUE

"Connective tissue" is a fibrous and most diverse tissue. It is one of the four traditional classes of tissues (the others being epithelial, muscle and nervous tissue). Connective Tissue (CT) is found throughout the body. In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of the body and act as an entity. CT has 3 main components: cells, fibers, and extracellular matrix, all embedded in the body fluids. Fibroblasts are the cells responsible for the production of connective tissue. The interaction of the fibers, the extracellular matrix and the water, together, form the pliable connective tissue as a whole. Connective tissue makes up a variety of physical structures including tendons and the connective framework of fibers in muscles, capsules and ligaments around joints, cartilage, bone, adipose tissue, blood and lymphatic tissue. CT is classified into three subtypes; Embryonic CT, Proper CT, and Special CT. The Proper CT subtype includes dense regular CT, dense irregular CT, and loose CT. The Special CT subtype includes cartilage, bone, adipose tissue, blood, hematopoietic tissue (tissue that makes blood cells) and lymphatic tissue. as well as the most abundant protein in mammals, Type-I collagen, making up about 25% of the total protein content.

1. Functions of Connective Tissue

Functions of connective tissue Storage of energy Protection of organs Providing structural framework for the body Connection of body tissues connects epithelial tissues to the muscle tissues 

Cells are spread through an extracellular fluid. Ground Substance - A clear, colorless, and viscous fluid containing

glycosaminoglycans and proteoglycans to fix the bodywater and the collagen fibers in the intercellular spaces. Ground substance slows the spread of pathogens.

Fibers. Not all types of connective tissues are fibrous though. Examples are adipose tissue and blood. Adipose tissue gives "mechanical cushioning" to our body. Although there is no dense collagen network in adipose tissue, groups of adipose cells are kept together by collagen fibers and collagen sheets in order to keep fat tissue under compression in place (for example the sole of the foot). The matrix of blood is plasma.

Both the ground substance and proteins(fibers) create the matrix for connective tissue.

2. Fiber Types and Characteristics of the Connective Tissue

Tissue Purpose Components Location Collagenous fibers - Alpha polypeptide chains tendon, ligament, skin, cornea, cartilage, bone, blood vessels, gut, and

intervertebral disc. Elastic fibers - elastic microfibrill & elastin extracellular matrix Reticular fibers - - liver, bone marrow, lymphatic organs

TYPES OF FIBERS

3. DISORDERS OF CONNECTIVE TISSUE 

Various connective tissue conditions have been identified; these can be both inherited and environmental.

Marfan syndrome - a genetic disease causing abnormal fibrillin. Scurvy - caused by a dietary deficiency in vitamin C, leading to abnormal collagen. Ehlers-Danlos syndrome - deficient type III collagen- a genetic disease causing

progressive deterioration of collagens, with different EDS types affecting different sites in the body, such as joints, heart valves, organ walls, arterial walls, etc.

Loeys-Dietz syndrome - a genetic disease related to Marfan syndrome, with an emphasis on vascular deterioration.

Pseudoxanthoma elasticum - an autosomal recessive hereditary disease, caused by calcification and fragmentation of elastic fibres, affecting the skin, the eyes and the cardiovascular system.

Systemic lupus erythematosus - a chronic, multisystem, inflammatory disorder of probable autoimmune etiology, occurring predominantly in young women.

Osteogenesis imperfecta (brittle bone disease) - caused by insufficient production of good quality collagen to produce healthy, strong bones.

Fibrodysplasia ossificans progressiva - disease of the connective tissue, caused by a defective gene which turns connective tissue into bone.

Spontaneous pneumothorax - collapsed lung, believed to be related to subtle abnormalities in connective tissue.

Sarcoma - a neoplastic process originating within connective tissue. Hemangiopericytoma - a neoplastic process.

4. STAINING OF CONNECTIVE TISSUE

For microscopic viewing the majority of the connective tissue staining techniques color tissue fibers in contrasting shades. Collagen may be differentially stained by any of the following techniques:

Van Gieson's stain Masson's Trichrome stain Mallory's Aniline Blue stain Azocarmine stain Krajian's Aniline Blue stain Eosin

MUSCLE TISSUETYPES OF MUSCLE TISSUE (SHOWN AT DIFFERENT MAGNIFICATIONS)

Muscle tissue is one of four basic biological tissues present in animals. It is a soft tissue that composes muscles.

Skeletal muscle or "voluntary muscle" is anchored by tendons (or by aponeuroses at a few places) to bone and is used to effect skeletal movement such as locomotion and in maintaining posture. Though this postural control is generally maintained as an unconscious reflex, the muscles responsible react to conscious control like non-postural muscles. An average adult male is made up of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body mass).

Smooth muscle or "involuntary muscle" is found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, blood vessels, and the arrector pili in the skin (in which it controls erection of body hair). Unlike skeletal muscle, smooth muscle is not under conscious control.

In vertebrates, there is a third muscle tissue recognized: Cardiac muscle is also an "involuntary muscle" but is

more akin in structure to skeletal muscle, and is found only in the heart.

Cardiac and skeletal muscles are "striated" in that they contain sarcomeres and are packed into highly regular arrangements of bundles; smooth muscle has neither. While skeletal muscles are arranged in regular, parallel bundles, cardiac muscle connects at branching, irregular angles (called intercalated discs). Striated muscle contracts and relaxes in short, intense bursts, whereas smooth muscle sustains longer or even near-permanent contractions.

COMPARISON OF TYPES

  smooth muscle cardiac muscle skeletal muscle

Anatomy      

  Neuromuscular junction None None Present

  Fibers fusiform, short (<0,4 mm) branching cylindrical, long (<15 cm)

  Mitochondria few numerous many to few (by type)

  Nuclei 1 1 few

  Sarcomeres none present, max. length 2,6 µm present, max. length 3,7 µm

  Syncytium none (independent cells) none (but functional as such) present

  Sarcoplasmic reticulum little elaborated moderately elaborated highly elaborated

ATPase little moderate abundant

Physiology      

  Self-regulation spontaneous action (slow) yes (rapid) none (requires nerve stimulus)

  Response to stimulus unresponsive "all-or-nothing" "all-or-nothing"

  Action potential yes none yes

  Arbeitsbereich Kraft/Längen-Kurve ist variabel im Anstieg der Kraft/Längen-Kurve am Maximum der Kraft/Längen-Kurve

RESPONSE TO STIMULUS

Type I, slow oxidative, slow twitch, or "red" muscle is dense with capillaries and is rich in mitochondria and myoglobin, giving the muscle tissue its characteristic red color. It can carry more oxygen and sustain aerobic activity.› Type I muscle fiber are sometimes broken down into Type I and

Type Ic categories, as a result of recent research. Type II, fast twitch muscle, has three major kinds that are, in

order of increasing contractile speed› Type IIa, which, like slow muscle, is aerobic, rich in mitochondria

and capillaries and appears red. Type IIx (also known as type IId), which is less dense in

mitochondria and myoglobin. This is the fastest muscle type in humans. It can contract more quickly and with a greater amount of force than oxidative muscle, but can sustain only short, anaerobic bursts of activity before muscle contraction becomes painful (often incorrectly attributed to a build-up of lactic acid). N.B. in some books and articles this muscle in humans was, confusingly, called type IIB.

Skeletal muscleSkeletal muscle is further divided into several

subtypes:

› Type IIb, which is anaerobic, glycolytic, "white" muscle that is even less dense in mitochondria and myoglobin. In small animals like rodents this is the major fast muscle type, explaining the pale color of their flesh.

Cardiac muscle (heart muscle) is a type of involuntary striated muscle found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle. The cells that comprise cardiac muscle, called cardiomyocytes or myocardiocyteal muscle cells, can contain one, two, or very rarely three or four cell nuclei.[1][2] Coordinated contractions of cardiac muscle cells in the heart propel blood out of the atria and ventricles to the blood vessels of the left/body/systemic and right/lungs/pulmonary circulatory systems. This complex of actions makes up the systole of the heart.

Cardiac muscle cells, like all tissues in the body, rely on an ample blood supply to deliver oxygen and nutrients and to remove waste products such as carbon dioxide.

 

Cardiac Muscle

Smooth Muscle Smooth muscle is an involuntary non-striated muscle. It is divided

into two sub-groups; the single-unit (unitary) and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by gap junctions to neighboring cells such that the whole bundle or sheet contracts as a syncytium (i.e., a multinucleate mass of cytoplasm that is not separated into cells). Multiunit smooth muscle tissues innervate individual cells; as such, they allow for fine control and gradual responses, much like motor unit recruitment in skeletal muscle.

Smooth muscle is found within the walls of blood vessels (such smooth muscle specifically being termed vascular smooth muscle) such as in the tunica media layer of large (aorta) and small arteries, arterioles and veins. Smooth muscle is also found in lymphatic vessels, theurinary bladder, uterus (termed uterine smooth muscle), male and female reproductive tracts, gastrointestinal tract, respiratory tract, arrector pili of skin, the ciliary muscle, and iris of the eye. The structure and function is basically the same in smooth muscle cells in different organs, but the inducing stimuli differ substantially, in order to perform individual effects in the body at individual times. In addition, theglomeruli of the kidneys contain smooth muscle-like cells called mesangial cells.

QUESTION

ANSWERS

  1. What are muscle tissues? How is the function of this tissue related to the typical characteristics of its cells?

= Muscle tissues are tissues made of cells able to perform contractions and thus to generate movement.

The function of the muscle tissue is to pull bones (skeletal striated muscle), to contract and move viscera and vessels (smooth muscle) and to make the heart to beat (cardiac striated muscle). The muscle cells have internal structures called sarcomeres where there are myosin and actin molecules disposed to create contraction and distension (movement).

2. What is the typical biological function of the connective tissues? How is

this function associated to the main features of its cells? = The typical function of the connective tissues is to fill empty spaces

among other body tissues. This function is related to the great capability of the cells of the

connective tissue to secrete substances that constitute extracellular material, like collagen and elastic fibers, creating a significant spacing between these cells.(There are other important biological features of the connective tissues, such as substance transportation, defense of the organism, etc.)

3. Of which type of tissue are cartilages and bones made? = Bones and cartilages, tissues with great amount of intercellular

material, are formed of connective tissue.

4. Are the cells of the connective tissue far or near to the others?

= The relative great spacing between cells is a typical feature of the connective tissue. There are much intercellular material generally secreted by the tissue cells.

5. What are the general functions of the connective tissues? = The main functions of the connective tissues are:

supporting and filling of spaces; cellular nutrition; energetic storage (fats); hematopoiesis (formation of blood, blood cells and blood components); immune defense (specialized cells).

6. What is connective tissue proper? = The name connective tissue proper is used to designate

the connective tissue that fills interstitial spaces as opposed to the specialized connective tissues (blood, bones, cartilage, adipose tissue, etc.). The connective tissue proper secretes collagen, elastin and reticular fibers.

 

7. What are the main cells of the connective tissue proper? What is the name given to the intercellular material that surround these cells?

= The main cells of the connective tissue proper are the fibroblasts, cells that secrete the intercellular material. These cells are the majority of cells of the tissue. Fibroblasts later are transformed into fibrocytes, mature cells with restricted secretory role.

The intercellular substance that fills the interstice is called interstitial matrix, or just matrix.

Cell Tissue - Image Diversity: fibroblast fibrocyte interstitial matrix

8. What are the three types of protein fibers of the connective tissue proper?

= The matrix of the connective tissue proper is made of collagen fibers, elastic fibers and reticular fibers.

Cell Tissue - Image Diversity: collagen fibers elastic fibers reticular fibers

  9. What is the function of the collagen fibers of the connective tissue? = There are different collagen types. The main function of these

proteins is to keep the shape and the structural rigidity of the tissue. (Collagen is the most abundant protein of the human body.)

 

10. Of which substance do elastic fibers of the connective tissue are made? What are some functions of these fibers?

= The elastic fibers are made of a protein called elastin. Elastic fibers abound in artery walls, helping the maintenance of the

arterial blood pressure in these vessels. They are also present in the lungs, providing them with elasticity (some respiratory diseases are caused by destruction of these fibers). In many other organs and tissues the elastic fibers are found in the interstitial matrix.

  11. What are the reticular fibers of the connective tissue and where can

they be found? = The reticular fibers are very delicate interstitial fibers made of a special

type of collagen known as collagen type III. They can be found in many organs and tissues such as in lymphnodes, in the spleen, in the liver, in blood vessels and also covering muscle fibers.

12. What are diseases of the connective tissue? What are some of them? = Diseases of the connective tissue are hereditary or acquired

diseases(many of autoimmune cause) characterized by deficiency in structure or function of components of the connective tissue, for example, deficiencies of collagen, elastin, etc. Some of such diseases are lupus, dermatomyositis, cheloid, scleroderma, mixed connective tissue disease, mucinosis and Marfan's syndrome.

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