HUMAN TISSUES BY DR QAZI IMTIAZ RASOOL

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HUMAN TISSUES BY DR QAZI IMTIAZ RASOOL Ex. H.O.D. PHYSIOLOGY GOVERNMENT MEDICAL COLLEGE SRINAGAR KASHMIR INDIA

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بسم الله الرحمن الرحيم:

بسم الله الرحمن الرحيم

Human tissues:

Human tissues DR QAZI IMTIAZ RASOOL

OBJECTIVES:

OBJECTIVES At the end of session, students should able to Define and classify tissue Describe different tissue Recall the function of tissue Indentify clinical application

Why Study Histology?:

Why Study Histology? Knowing the difference between normal and abnormal tissue is the first step in diagnosis and treatment of patients.

Slide 5:

An aggregation of cells and their products of similar structure and embryonic origin that perform a common function Cells group together in the body to form tissue Greatest form teamwork Definition :

Slide 6:

Epithelial = covering Connective = support Muscle = movement Nervous = control Most organs contain all 4 types i.e Skin, our largest organ 4 types tissue

Slide 7:

Greek " Epi " means, “upon," Found above a connective tissue " Theli " meaning "tissue“ 3% - body weight Don’t move, do not send messages Cells - all touching one another Lines the cavities, tubes, ducts, and blood vessels inside the body Epithelial layers are avascular , so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membran e By  tight junctions and  desmosome s General Description Epithelial Tissue

3 Basic Shapes:

3 Basic Shapes Squamous – like scales, or pancakes (“being squashed like a pancake ”) Cuboidal – looks like cubes Columnar – longer and look like columns

Classification of Cell Organization:

Classification of Cell Organization 1.Simple – single layer of cells; typically found where absorption and filtration occur or a single layer of epithelial is needed - simple squamous -simple cuboidal -simple columnar 2.Stratified – layers of cells; common in areas where protection is needed like the skin - stratified squamous -stratified cuboidal -stratified columnar

Slide 10:

Simple epithelium is one cell thick, that is, every cell is in direct contact with underlying basement membrane It is generally found where absorption and filtration occu r

Slide 11:

All epithelial cells rest on a basement membrane, on which epithelium can grow and regenerate after injuries Epithelial tissue is  innervated , but  avascular Thus epithelial tissue must be nourished by substances diffusing from the blood vessels in the underlying tissue The basement membrane acts as a selectively permeable membrane that determines which substances will be able to enter the epithelium

Slide 12:

Glandular Epithelia Glands are specialized epithelial cells that perform secretion illustrate a basic biological principle: that structure closely correlates with function Glandular Epithelium

Confusing Epithelial Tissue:

Confusing Epithelial Tissue Transitional Epithelium – stratified tissue that can’t make up its mind as to whether it is squamous or cuboidal Shape of cells depends upon the amount of stretching (ex: bladder )

Slide 14:

Mucous or mucosa – lining of tubes; moistens and protects from enzymes (stomach, trachea, and vagina) Serous or serosa – outside of organs; lubricates (all thoracic, abdominal and pelvic organs) Cutaneous or skin – body surface; protection Synovial – synovial joints; lines and protects synovial cavities (elbow, knee, hip, etc.) Types of Epithelium MEMBRANES

Functions of epithelium: :

Protection,(i.e. protecting the underlying tissues from tear and wear.) Absorption, Sensation, Secretion (by glandular epithelium). Reabsorbs lubricate structures Contains receptors which respond to stimuli Filters, Excretion (by epithelium of the kidney). Reproduction (by the germinal epithelium of the gonads). Transcellular transport Detection of sensation Functions of epithelium:

Slide 16:

3(actually 2) basic forms of elements:(inter-cellular substance) 1.Cells 2.Extra-cellular matrix 3.Fibers:- a) Collagen (white) fibers, b) Elastic (yellow)fibers c) Reticular (fine collagen) (N.B.: Collagen , colla = glue) Connective Tissue

Slide 17:

derived from mesoderm ,in the embryo 2 types: 1. True Connective Tissue 1. Loose Connective Tissue a. Areolar tissue Widely distributed under epithelia b. Adipose tissue Hypodermis, within abdomen, breasts c. Reticular connective tissue Lymphoid organs such as lymph nodes 2. Dense Connective Tissue a. Dense regular connective tissue Tendons and ligaments b.Dense irregular connective tissue Dermis of skin, submucosa of GIT 2 . Specialized Connective Tissue a. Cartilage b. Bone c. Blood . Connective Tissue

Slide 18:

Fibroblasts : Secrete both fibers and ground substance of the matrix (wandering) Macrophages : Phagocytes that develop from Monocytes (wandering or fixed) Plasma Cells : Antibody secreting cells that develop from B Lymphocytes (wandering) Mast Cells : Produce histamine that help dilate small blood vessels in reaction to injury (wandering) Adipocytes : Fat cells that store triglycerides, support, protect and insulate (fixed) True Connective Tissue Cells

Clinical application:

Clinical application 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 coll Sarcoma - a neoplastic process originating within connective tissue

Function of Connective Tissue:

Function of Connective Tissue Connects, binds and supports structures, Tendons , ligaments, etc. Protects & cushions organs and tissues, Insulates (fat) Transports substances (blood).

Slide 21:

3 types 1 Skeletal muscle is attached to bone controlled by conscious effort ( voluntary ).. 2. Smooth muscle tissue lacks 1.Striations, is uninucleate , and consists of spindle-shaped cells . 2 involuntary muscle 3.Cardiac muscle tissue only in the heart consists of branching fibers that are connected to each other with intercalated discs, involuntary muscle striated . Muscle Tissues:

Muscle Tissue:

Muscle Tissue Functions: Movement Locomotion Maintains posture Produces heat Facial expressions Pumps blood Peristalsis

Nervous Tissue:

Nervous Tissue Highly cellular 2 cell types Neurons Functional, signal conducting cells Neuroglia Supporting cells 3/1/2017 23

Slide 24:

How many synapses are in one neuron? 1,000 to 200,000!! TRILLION INTERNEURONS 1-Mar-17 24

Nervous Tissue:

Nervous Tissue Functions : Regulates & controls body functions Generates & transmits nerve impulses Supports, insulates and protects impulse generating neurons.

Tissue Repair (Wound Healing):

Tissue Repair (Wound Healing) 2 ways: Regeneration Replacement of destroyed tissue by the same kind of cells Fibrosis Repair by dense (fibrous) connective tissue (scar tissue) Either of 2 depends on: Type of tissue damaged Severity of the injury Clean cuts (incisions) heal more successfully than ragged tears of the tissue

Events in Tissue Repair:

Events in Tissue Repair Inflammation Capillaries become very permeable Clotting proteins migrate into the area from the bloodstream A clot walls off the injured area Granulation tissue forms Growth of new capillaries Phagocytes dispose of blood clot and fibroblasts Rebuild collagen fibers

Development Aspects of Cells and Tissues:

Development Aspects of Cells and Tissues Growth through cell division continues through puberty Cell populations exposed to friction (such as epithelium) replace l ost cells throughout life Connective tissue remains mitotic and forms repair (scar) tissue With some exceptions, muscle tissue becomes amitotic by the end of puberty Nervous tissue becomes amitotic shortly after birth.

Developmental Aspects of Cells and Tissues:

Developmental Aspects of Cells and Tissues Injury can severely handicap amitotic tissues The cause of aging is unknown , but chemical and physical insults, as well as genetic programming, have been proposed as possible causes Neoplasms , both benign and cancerous, represent abnormal cell masses in which normal controls on cell division are not working Hyperplasia (increase in size) of a tissue or organ may occur when tissue is strongly stimulated or irritated Atrophy (decrease in size) of a tissue or organ occurs when the organ is no longer stimulated normally

Slide 30:

Inherited diseases caused by mutation in gene coding for collagen Repair to damaged tissue is delivered by support of connective tissue Weakness and wasting of muscle is known as atrophy Malignant growth is cancer -Carcinoma : malignant growth of epithelium -Sarcoma : malignant growth of connective tissue Clinical application

Slide 31:

Neoplasia Metaplasia Epithelial cell tumours Carcinoma Adenocarcinoma Bullous pemphigoid First degree burns

Slide 32:

Can You Identify the Classes of Epithelium? A B C D E Quiz!!

SUMMARY:

SUMMARY

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