Types of Tissues PDF

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1 © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.  Types of Tissues Tissue – a collection of cells of the same type that perform a common function There are 4 major tissue types in the body: 1. Connective tissue – binds and supports body parts 2. Muscular tissue – moves the body and its parts 3. Nervous tissue – conducts nerve impulses 4. Epithelial tissue – covers body surfaces; lines body cavities © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 2  Connective tissue Connective tissue" is a term used for various body tissues that connect, support, and bind other tissues Major functions of connective tissues: 1. Bind other tissues and support organs and the whole body. 2. Protect the body. 3. Insulate sensitive organs such as kidneys. 4. Store fuel (in fat cells). 5. Help transport substances throughout the body.  Connective tissue The three primary constituents of any connective tissue are cells, fibers, and matrix, which is an amorphous extracellular substance A. Connective tissue cells : 2. Fibroblast: This spindle-shaped cell with processes is the main component of connective tissue. The cell is formed like a spindle and has processes. Function: It creates and preserves the matrix and fibers of connective tissue. 3. Immune cells: These are moving blood cells, including mast cells, lymphocytes, and macrophages. Function: They contribute to immunity. 4. Specialized cells: discovered a specific connection. Tissue, including chondrocytes in cartilage, osteocytes in bone, and adipocytes in adipose tissue  B. Connective tissue Fibers 1. Collagen fibers: These fibers are strong and non-stretching. Among all fiber types, they are the most prevalent. Type I collagen protein is present in them. 1. Reticular fibers: These tiny, delicate fibers are what give organs their fiber networks. Have collagen type III protein. They create a network of tiny fibers and are supportive. 2. Elastic fibers: Since they are elastic, they can be stretched and stretched again to a previous length. They have proteins called elastin C. Matrix: The ground substance, the connective tissue matrix, is a thick gel composed of water and other glycoproteins. Its high-water content causes tissues to become hydrated and aids in the diffusion of nutrients, nourishing the tissue. Connective Tissue  Connective Tissue Types There are three main types of connective tissue: 1. Fibrous 2. supportive 3. Fluid © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 8  1. Fibrous connective tissue 1. Loose fibrous connective tissue Loose fibrous connective tissue supports epithelium and many internal organs Areolar, adipose, and reticular connective tissues are the three subtypes of loose connective tissue 1. Areolar connective tissue. It has scant tissue that resembles mesh and an uneven network of collagen and elastic fibers in a sizable amount of matrix (ground material). 2. Adipose connective tissue: The predominant cell type in this tissue is adipocytes or fat cells. 3. Reticular connective tissue: It is not the same as areolar connective tissue since it has fine reticular fibers rather than collagen fibers. 5 1. Fibrous connective tissue 5  1. Fibrous connective tissue A. Dense connective tissue: Dense connective tissues have more fibers. 2. Dense regular C. T.: mostly made up of collagen fibers that are organized uniformly and closely packed 2. Dense irregular C. T Consists mainly of collagen fibers that are organized erratically and closely together 3. Elastic C. T.: It is primarily composed of elastic fibers. 5  1. Fibrous connective tissue A. Dense connective tissue: Dense connective tissues have more fibers. 2. Dense regular C. T.: mostly made up of collagen fibers that are organized uniformly and closely packed 2. Dense irregular C. T Consists mainly of collagen fibers that are organized erratically and closely together 3. Elastic C. T.: It is primarily composed of elastic fibers. 5  Connective Tissues Found in the Knee (Figure 4.2) (all photos): © ED Reschke Jump to long description © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 13  2. Supportive connective Two major types: cartilage and bone tissue Cartilage It is an avascular connective tissue that reinforces the walls of the upper respiratory system, the external ear, and caps bones and extremities at joints. Cartilage cells: The chondrocytes are the mature principal cartilage cells lodged in the lacunae (cavities in the cartilage matrix). Matrix of the cartilage: Cartilage is composed of a rubbery substance called glycosaminoglycan and water. Fibers of the cartilage: Cartilage may contain collagenous or elastic fibers according to its type Hyaline cartilage – fine collagen fibers, found in the tip of the nose, ends of long bones and the fetal skeleton Elastic cartilage – lots of elastic fibers, found in the outer ear Fibrocartilage – strong collagen fibers, found in the disks between vertebrae © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- 14 Hill Education. Cartilage Type  2. Supportive connective Bone tissue □ Rigid connective tissue, matrix is made of collagen and calcium salts □ There are two types of bone tissue: compact and spongy Compact bone makes up the shafts of long bones I. Consists of cylindrical structural units called osteons II. The central canal contains blood vessels and nerves III. Bone cells are located in lacunae Spongy bone is inside the ends of long bones, Lighter than compact bone, but strong © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 16  3. Fluid There are two types ofConnective fluid connective tissue: blood and lymph Blood: Made of a fluid matrix called plasma and cellular components called formed elements. 3 formed elements: I. Red blood cells (erythrocytes) – cells that carry oxygen II. White blood Cell (leukocytes) – cells that fight infection III. Platelets (thrombocytes) – pieces of cells that clot blood Lymph Derived from the fluid surrounding the tissues. Contains white blood cells. Lymphatic vessels absorb excess interstitial fluid and return lymph to the cardiovascular system © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 17 2. Muscular Tissue 1-The muscular tissues are connected to the same nerve bundles. 2-The nerve impulse from the brain tells the muscles to contract. 3-Each muscle cell contains the proteins actin and myosin. These proteins slide past one another when the signal is received for contraction. 4- A single cell contracts up to 70% in length. The entire muscle shortens during contraction 5-Muscular tissues help in the movement of bones, squeeze different organs, or compress chambers © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 19  Properties of Muscular Tissue Properties of Muscular Tissue 1- Contractibility– It is the ability of muscle cells to shorten forcefully. 2- Extensibility– A muscle has the ability to be stretched. 3- Elasticity– The muscles have the ability to recoil back to its original length after being stretched. 4- Excitability– The muscle tissue responds to a stimulus delivered from a motor neuron or hormone. 2. Muscular Tissue Muscular Tissue Moves the Body Specialized to contract, cells are called muscle fibers Three types: skeletal, smooth, and cardi The muscular tissue is of three types: Skeletal Muscle Tissue Smooth Muscle Tissue Cardiac Muscle Tissue © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 21  1. Skeletal muscle These muscles are attached to the skeleton and help in its movement. These muscles are also known as striated muscles because of the presence of alternate patterns of light and dark bands. These light and dark bands are sarcomeres which are highly organized structures of actin, myosin, and proteins. These add to the contractility and extensibility of the muscles. skeletal muscles are voluntary muscles composed of muscle fibers. The cells of these tissues are multinucleated.. They bring about the movement of the organs of the © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 22 body Skeletal Muscle Tissue  2. Smooth muscle 2. Smooth muscle These are non-striated, involuntary muscles controlled by the Autonomous Nervous System. It stimulates the contractility of the digestive, urinary, reproductive systems, blood vessels, and airways. The actin and myosin filaments are very thin and arranged randomly, hence no striations. The cells are spindle-shaped with a single nucleus © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 24  3. Cardiac Muscle These are found only in the heart. These are involuntary muscles and the heart pumps the blood through cardiac contractions. The cells of the cardiac muscles known as the cardiomyocytes are striated. They are single-celled and uninucleated. The ends of the cells are joined and the junctions are called intercalated discs. The cells are attached to each other by desmosomes  3. Nervous Tissue Function Of Nervous Tissue Neurons generate and carry out nerve impulses. They produce electrical signals that are transmitted across distances, they do so by secreting chemical neurotransmitters. Responds to stimuli Carries out communication and integration Provides electrical insulations to nerve cells and removes debris Carries messages from other neurons to the cell body  3. Nervous Tissueor the nerve tissue is the main tissue of our nervous Nervous system. It monitors and regulates the functions of the body. Nervous tissue consists of two cells (neurons and neuroglia) Neuron Has three parts: dendrites, a cell body, and an axon I. Dendrites carry information toward the cell body I. The cell body contains the nucleus and other organelles II. Axon conducts nerve impulses away from the cell body, covered in myelin, a fatty substance Nerves – bundles of axons traveling to and from the brain and spinal cord Neuroglia : Main function is to support and nourish neurons © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 27  4. Epithelial tissue Epithelial tissue consists of layers of tightly interconnected cells that form a protective covering on the body's outer surface and line the internal organs and cavities. The main functions of epithelial tissues are: Epithelial Tissue Functions 1- Protection: As it covers the entire body surface, it is the first line of defence against any kind of mechanical injury, chemical exposure, excessive fluid loss and infections. Ciliary projections present in the nose or upper respiratory tract, trap the dust particles and prevent it from entering the body 2- Absorption: The epithelial lining of the digestive tract absorbs water and nutrients 3- Exchange of substances: Epithelial tissue regulates the exchange of substances between body and external environment as well as the internal exchange between different parts of the body. Everything that enters the body or enters the bloodstream by absorption has to cross the epithelial barrier 4-Sensation: Sensory receptors are present in the epithelial tissue of the nose, eyes and ears, taste bud, etc. that help in transmitting signals from the external stimuli to the brain 5- Secretion: Various glands made up of epithelial cells secrete hormones, enzymes, saliva, mucus, sweat, etc.  4. Epithelial Tissue (epithelium, orProtects plural, epithelia) I. Made of tightly packed cells, Lines body cavities, covers body surfaces, and is found in glands II. Anchored by a basement membrane on one side and is free on the other side III Named for the number of cell layers and the shape of the cells. I. Simple epithelium Single layer of cells II. Stratified epithelium Multiple layers of cells III. Pseudostratified © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 30  Epithelial Tissue (Figure 4.7) a. Classes of epithelium b. Cell shapes Jump to long description © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 31  I. Simple epithelia Comprised of a single layer of cells sitting on a basement membrane, the simple epithelium has four different types 1. Simple squamous epithelium It consists of a single layer of flattened (plate-like) cells. That is, found in the lungs, where it functions in gas exchange 2. Simple cuboidal epithelium Single layer of cube-shaped cells © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 32  3. Simple columnar epithelium: Single layer of column-shaped cells II. Pseudostratified columnar epithelium This simple epithelium type is made up of a single layer of columnar cells with different heights having the look of having multiple layers. Location: Mostly located in the respiratory tract lining, it also covers the epididymis duct © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 33  III. Stratified epithelia Consists of several layers of cells (Fig. 3) resting also on a basement membrane. There are four types of this epithelium 1. Stratified squamous epithelium: Consists of several layers of cells, the most superficial one is squamous in shape, which is actually formed of dying cells. There are two subtypes of this epithelium, keratinized and non-keratinized. Location: The non-keratinized one forms the lining epithelium of the mouth esophagus, and vagina. The keratinized one forms the epidermis of skin. © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 34  III. Stratified epithelia 1. Stratified cuboidal epithelium: Consists of several layers of cells, the most superficial one is cuboidal. Location: Lines the ducts of sweat, salivary, and mammary glands. 2. Stratified columnar epithelium: Consists of several layers of cells, the most superficial one is columnar. Location: Male urethra. Function: Protection and secretion. 3. Transitional epithelium: Consists of multiple layers of epithelial cells the most superficial one is pear shaped. Location: Found in the lining of the ureter and urinary bladder. © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw- Hill Education. 35