Connective Tissue Lecture Notes PDF

 Presentation September 30, 2024  Connective tissue proper Loose connective tissue Areolar Adipose Reticular Dense connective tissue Regular Irregular  Areolar See a lot of ↓...

 Presentation September 30, 2024  Connective tissue proper Loose connective tissue Areolar Adipose Reticular Dense connective tissue Regular Irregular  Areolar See a lot of ↓ ground substance quite loose shows little specialization. It contains all the cell types and fibers previously described is distributed in a random, web-like fashion. Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes as keep It loose cells you have more room to more which gives you mid support  Adipose tissue very specific consists mostly of fat storage cells, with little extracellular matrix Fat cell elipocyte adipocyte , Lipid #  Reticular Connective Tissue supportive framework of reticular fibers for soft organs such as lymphatic tissue, the spleen, and the liver delicate support  made up Of tendon collagen fibers& muscle Dense Connective Tissue: Regular ligament to bone bone to bone Dense connective tissue contains more collagen fibers than does loose connective tissue. collagenous Fibers Dense regular connective tissue fibers are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fiber orientations. Fibroblasts Ligaments and tendons are made of makeagenous dense regular connective tissue fibers dense not sho is eX ohened - regular ecollagen rmIS as regular de Skin  CHONDRO = cartilage ~ Cartilage The distinctive appearance of cartilage is due to glycosaminoglycans called chondroitin sulfates, which bind with proteins to form proteoglycans. Embedded within the cartilage matrix are chondrocytes, or cartilage cells, and the space they occupy are called lacunae (singular = lacuna). A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. bloenood nodrect vessels Cartilaginous tissue is avascular, thus all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues. #  Types of Cartilage The three main types of cartilage tissue are: 1. hyaline cartilage 2. fibrocartilage 3. elastic cartilage  Hyaline Cartilage the most common type of cartilage under the microscope, tissue samples appear clear /homogenous the surface of hyaline cartilage is smooth strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints end of bone articular cartilage) embryonic skeleton before bone formation nucle a plate (growth plate) embryonic Skeleton chondrocytes growth Cepiphyseal place  Fibrocartilage pink = hyaline Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. Menisci in the knee joint and the intervertebral discs are examples of fibrocartilage.  Elastic Cartilage Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue gives rigid support as well as elasticity. The external ear contains elastic cartilage dark fibers = elastic fibers - ear - epiglottis * answer on exams Is never all of the above Presentation October 04, 2024  Skin-Integumentary Skin * location all on exam The skin is composed of two main layers * on exam3 cornifed protection 1. epidermis, made of a keratinizedwater prevent loss stratified squamous epithelium * know what its made of 2. dermis, mostly made of dense, epithelium irregular connective tissue that houses blood vessels, hair dent Vascular as follicles, and sweat glands Beneath the dermis lies the superficial Fascia hypodermis, which is composed mainly wh of adipose tissue. below Skin filled ↑ lipocytes primarily made of  Thin Epidermis ThICK composed of keratinized, stratified squamous epithelium. made of four or five layers of dead a cel an epithelial cells, depending on its epidermis location in the body. dermis does not have any blood vessels within it (i.e., it is avascular). Can be classified as thin or thick skin Histology of Thick Epidermis: Five Layers TICK Skin - large lot of Keratin where layers of dead theres lots of function cell In body filled wh palm of - soleof veratin - hands feet Thin & variations In both most parts of - Skin  dermis Layers of ① Stratum basale Keratinocytes Stratum Basale divide single layer of mostly basal cells A basal cell is a cuboidal-shaped stem cell that is a precursor of the keratinocytes of ↑ objective is to fill the epidermis. cells with Keratin All of the keratinocytes are produced from this single layer of cells, which are constantly going through mitosis to produce new cells. As new cells are formed, the existing cells are pushed superficially away from the stratum basale. ncuboidal  ② stratum spinosum held by desmosomes Stratum Spinosum spiny in appearance due to the protruding cellcells Shrink processes that join the cells via desmosomes.through preparation desmosomes strengthen the bond between the cells. strong cells neid don't really exist together the “spiny” nature of this layer is an artifact of by ↳ the staining process. desmosomes composed of eight to 10 layers of keratinocytes, formed as a result of cell division in the stratum -- basale  ③ stratum granulosum Stratum Granulosum Granular appearance The cells (three to five layers deep) become flatter, their cell membranes thicken, and they generate large amounts of the keratin filaments, which is fibrous, and keratohyalin granules · significantentual formation ara keratohyalin granules binds keratin filamentsveratin together to form keratin  Lamellar Bodies rele a ased get Cells of granulosum contain and secrete lamellar bodies (placing made prod lipids and proteins) into the extracellular space. This results in the formation of preventsfrom the hydrophobic lipid envelope watermoving in responsible for the skin's barrier + too much properties. evaporation a fromcoming  e cells are dead above stratum granulosum and filled wh Stratum Lucidum Keratin thick skin only present in translucent layer of the epidermis located just above the stratum granulosum found only in the thick skin The keratinocytes are dead and flattened Contains eleiden (an intermediate form of keratin), a clear protein rich in lipids, derived from keratohyalin,  Stratum Corneum has most variability in thickness The stratum corneum is the most superficial layer of the epidermis The increased keratinization (also called cornification) of the cells in this layer gives it its name. In thick skin, there are usually 15 to 30 layers of cells in the stratum corneum. far from any blood supply This dry,&dead layer helps prevent the penetration of microbes and the dehydration of underlying tissues, and provides a mechanical protection against abrasion. Cells in this layer are shed periodically and are replaced by cells pushed up from the stratum granulosum (or stratum lucidum in the case of the palms and soles of feet). The entire layer is replaced during a period of about 4 weeks. callus caused by thickening Of A stratum corneum hypodermis ↓ superficial to deep fasad articular carriage made of hyaline cartilage Presentation October 07, 2024  Dermis The dermis might be considered the “core” of the integumentary system (derma- = “skin”), Distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). vascular Contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. Made of two layers of connective tissue  appearance Layers of Dermis gooda ent wavyds ↑ Papillary Layer Immediately below dermis The papillary layer is made of loose, areolar connective tissue. This superficial layer of the dermis projects into the stratum loose connective basale of the epidermis to form finger-like dermal papillae tissue usually under epithelium Reticular Layer Underlying the papillary layer is the much thicker reticular most of layer, composed of dense, irregular connective tissue. dermis- Elastic fibers provide some elasticity to the skin E Collagen fibers provide structure and tensile strength P'stuff Is collagen  Hypodermis The hypodermis (also called the subcutaneous layer or superficial fascia) is a layer directly below the dermis and serves to connect the skin to the underlying tissue. It is not strictly a part of the skin, the border between the hypodermis and made dermis can be difficult to distinguish. mostly consists of well-vascularized, loose, areolar connective tissue and adipose tissue, which aposea functions as a mode of fat storage and provides insulation and cushioning for the integument.  Pigmentation The color of skin is influenced by a number of pigments: melanin carotene hemoglobin  Melanin Melanin is a complex polymer that originates from the amino acid tyrosine. Types in skin  Eumelanin – varying degrees of brown to black  gives color to skin  absorbs harmful UV rays and protects against cellular damage from UV light exposure  Typically, all humans have the same number of melanocytes. However, the amount of melanin produced by these melanocytes varies.  Melanin produced by cells called melanocytes melanocytes are found throughout the stratum basale of the epidermis. melanin is transferred into the keratinocytes via a cellular granules called a melanosome gives skin its color and also helps protect the living cells of the epidermis from ultraviolet (UV) radiation damage. in -deepbasal ePh dermis In layer Melanocytes (melanosomes  Melanosomes membrane-bound spherical to elliptical granules within a melanocyte functions in the storage, and transport of melanin transfer melanin from melanocytes to keratinocytes in skin to form perinuclear melanin caps /form umbrella covering nucleus  Melanin Melanin occurs in two primary forms. black and brown associatedsome hairs red color - Pheomelanin is a reddish-yellow pigment Dark-skinned individuals produce more melanin than those with pale skin. genetics has a lot to do w/ It Exposure to the UV rays increases melanin production Protects the DNA of epidermal cells from UV ray damage Too much melanin can interfere with the production of tanning-making melanin vitamin D: important nutrient for immunity and calcium freckles-making blotches absorption. of melanin  Hairs hair originate in an epidermal penetration of the dermis called the hair follicle. the hair bulb forms the base of the hair follicle and includes a layer of mitotically active basal cells called is signal the hair matrix. vascular here Sends very loose issue to matux ecoma The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and lessthe - epidermatterms nerve endings from the dermis makes hair matrx cells-divide-push follicle upwards and eventually become Keratinized to roof + shaft  Arrector Pili Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, works better making the external hair shaft “stand up.” in animals The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps smooth musce and even more obvious in animals ↓ involuntary connects at angle + when it contracts makes hair stand  Glands > - make product enhe gladse product on sureare located Two Types 1. Suderiferous (Sweat) 1. Eccrine 2. Apocrine 2. Sebaceous  Sweat Glands - Eccrine An eccrine sweat gland is type of gland that produces a hypotonic sweat for thermoregulation. abundant on the palms of the hand, the soles of the feet, and the forehead They are coiled glands with the duct rising up to not a pore on the skin surface. associated [ W/ exocytosis hair follicle Utilizes merocrine secretion composed mostly of water, with some salt and associated some antibodies hypotonic evaporation + wh hair follicles certain areas In phmary function = themoregulation # under arms, genital region  Sweat Gland - Apocrine associated with hair follicles in hairy areas, such as armpits and genital regions. larger than eccrine sweat glands with the duct normally emptying into the hair follicle. contains protein, lipid, other organic get ena do compounds. likes It the sweat thicker and subject to bacterial decomposition and subsequent smell. release of this sweat is under both nervous and hormonal control  most Skin is important Sebaceous Glands ↳ more prone to cracking sebaceous glands are associated with hair follicles. excrete sebum, a mixture of lipids, onto the skin surface, thereby naturally lubricating the dry and dead layer of keratinized cells of the stratum corneum, keeping it pliable. The fatty acids of sebum also have antibacterial properties Uses holocrine secretion ~ I whole cells becomes parto f sebumporta Skinba,as Histology of Sebaceous Gland O  - llgaments +tendons ↓ dense regular connective tissue strongest penchonanuma cartilage Surround Presentation October 09, 2024  Bone Cells Although bone cells compose a small amount of the bone volume, they are crucial to the function of bones. Four types of cells are found within bone tissue:- -make > something (bone) 1. osteoblasts, -bone 2. osteocytes, more mature bone > - 3. osteogenic cells, phmitare > - cells that 4. osteoclasts form osteoblasts  Bone Cells and Tissue The osteoblast is the bone cell responsible for forming new bone and is found in the growing portions of bone, including the periosteum and endosteum. Osteoblasts synthesize and secrete the collagen matrix and calcium salts. As the secreted matrix surrounding the osteoblast calcifies, the osteoblast become trapped within it and becomes as an osteocyte, the primary cell of mature bone. Each osteocyte is located in a space called a lacuna and is surrounded by bone tissue. costeoblasts bony me ↑ lacuna ye  Osteocytes Osteocytes make up 90–95% of cells in bone tissue in contrast to osteoclasts and osteoblasts making up ~5% (40).... Residing within the lacuna of the mineralized bone matrix osteocytes form dendritic processes Lospocytes that extend out from their cell bodies reside here in into spaces known as canaliculi.  remodel Osteoclast -get > - - removes bone more calcium The cell responsible for bone resorption, or breakdown, and calcium release is 'breaking down bone the osteoclast. They are found on bone surfaces, are not completely multinucleated, and originate from surrounded - only & multi nucleated bone - cell monocytes and macrophages, by bone much larger that Is Osteoclasts are continually breaking down old bone while osteoblasts are continually forming new bone. Osteoblasts The dynamic nature of bone means that new tissue is constantly formed, and old, injured, or unnecessary bone is dissolved. M  Osteogenic Cells < primative Osteogenic cells are the only bone cells that divide. Osteogenic cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bones. harder to identify bes look like other phmative cell  Summary Osteogenic cells are the only bone cells that divide. Osteogenic cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bones. Osteoblasts synthesize and secrete a collagen matrix and calcium salts. When the area surrounding an osteoblast calcifies, the osteoblast becomes trapped and transforms into an osteocyte, the most common and mature type of bone cell. Osteoclasts, the cells that break down and reabsorb bone, stem from monocytes and macrophages rather than osteogenic cells.. There is a continual balance between osteoblasts generating new bone and osteoclasts breaking down bone.  Compact and Spong Bone Two basic structural bone types. compact bones Spongy bone Most bones contain compact and spongy osseous tissue, but their distribution and concentration vary based on the bone’s overall function. The differences between compact and spongy bone are best explored via their histology.  Compact and Spongy Bone Compact Bone Compact bone is the denser, stronger of the Osteon/haversion m blood vessels , surrounded by bone etc as Istorgara two types of bone tissue to lent It can be found under the periosteum and in the lamellae diaphyses of long bones, used of where it provides support central canal-centerston makescompateng ground and protection. section of compact bone what compact be - osteocyles ↑ eriosteum - dense Irregular connective +issue placed brin lamellae circumferential lamellae-circular layer of bone that completely surround bone central canal  Microscopic Structure of Compact Bone The microscopic structural unit of compact bone is called an osteon, or Haversian system. Each osteon is composed of concentric rings of calcified matrix called lamellae (singular = lamella). connective tissue Running down the center of each osteon is the central canal, or Haversian canal, which contains blood vessels, nerves, and lymphatic vessels. If you break bone , It will bleed bone = Vascular Osteon (histology)  Canaliculi The osteocytes are located inside spaces called lacunae (singular = lacuna), found at the borders of adjacent lamellae. -nutuents + info hom centraa little channels run from central canal to lacuna Canaliculi connect with the canaliculi of other lacunae and eventually with the central canal. This system allows nutrients to be transported  Spongy Bone Spongy bone, also known as cancellous bone or a trabecular bone, is a very porous type of bone found in animals. surr Still o unded highly vascularized and contains red bone marrow. usually located at the ends of the long bones (the epiphyses), with the harder compact bone surrounding it. * consists of plates (trabeculae)* flied witharrow bone canaliculi connect to the adjacent cavities, instead usually lighter space between of a central haversian canal, to receive their blood , which contain RBC supply. red color-active no haversian in trabecullae-see WBC system components but don't organize themselves  z. endosteum Spongy Bone cover trabeculae loose connective tissue Trabeculae are covered by the endosteum Trabecula forms along lines of stress to direct forces out to the more solid compact bone providing strength to the bone. Spaces of the trabeculated network make bones lighter so that muscles can move them more easily. Spaces in many spongy bones contain red marrow (hematopoiesis occurs).  Chemical Composition of Bone Bone is made up of: organic component – 40% z flexibility Consists of: Cells Osteod-maten all e cels hylauronic acid Collagen and GAGs (chondroitin sulfate (CS) and small amounts of hyaluronic acid. inorganic fro component – 60% enter z comes calcification erage m -major inorgan Hardness * Calcium Phosphate combined with hydroxyl (OH) to form hydroxyapatite Interstitial and Appositional Growth of Cartilage Cartilage can grow in two ways: Interstitial growth - chondrocytes grow and divide and lay down more matrix inside the existing cartilage. Appositional growth - new surface layers of matrix are added to the pre-existing matrix by new chondroblasts from the perichondrium.  Bone Formation 1. Endochondral requires initial In endochondral ossification, bone develops by replacing hyaline hyaline cartilage. cartilage cartilage does not become bone. cartilage serves as a template to be completely replaced by new bone. 2. Intramembranous Ossification some don't start as cartilage In Intramembranous ossification a cartilage model is not used melanin cell projects by covering theucleus Presentation October 11, 2024  Gross Anatomy of a Long Bone A long bone has two parts: the diaphysis and the epiphysis. The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. internala The epiphysis is the wider section at each end of the bone (plural = epiphyses), dontharassop growing Each epiphysis meets the diaphysis at the metaphysis, the narrow area that contains the epiphyseal plate (growth plate), a layer ofuhyaline cartilage in a growing bone. When the bone stops growing (approximately 18–21 years), the cartilage is replaced by osseous tissue and the epiphyseal plate becomes an epiphyseal line.  Gross Anatomy of a Long Bone (Continued) The hollow region in the diaphysis is called the medullary cavity, which is filled with yellow marrow. The walls of the diaphysis are composed of compact alwaysnaMom bone. a The epiphysis (plural is filled with spongy bone.- Covering the epiphysis is articular (hyaline) cartilage - hyaline cartilage forms articular cartilage  Endosteum and Periosteum The medullary cavity is lined by a delicate membrane called the endosteum (end- =covers“inside”; oste-of= “bone”). Loose aredit trabeculae spongy bone The outer surface of the bone is covered with a fibrous , membrane called the periosteum (peri- = “around” or “surrounding”). ↳aroundbeearct contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments also attach to bones at the periosteum. VASCULAR The periosteum covers the entire outer surface except at joints. In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.  Bone Formation 1. Endochondral In endochondral ossification, bone develops by replacing hyaline cartilage. embryonic cartilage does not become bone. most bones are endochondral cartilage cartilage serves as a template to be completely replaced by new bone. 2. Intramembranous Ossification In Intramembranous ossification a cartilage model is not used Interstitial and Appositional Growth of Cartilage Cartilage can grow in two ways: Interstitial growth - chondrocytes grow and divide and lay down more matrix inside the existing cartilage. Appositional growth - new surface layers of matrix are added to the pre-existing matrix by new chondroblasts from the perichondrium. laying something on top of something  endroblasts afreventat Endochondral Bone Formation - - into mesenchymal cells ~ at about 6 to 8 weeks mesenchymal cells mesenchyme differentiate into chondroblasts that form ↓ connective the hyaline cartilage model of the bones. early tissue which Perichondrium surrounds the cartilage contain stem cells model that takes the shape of the future bone and grows by both interstitial and appositional growth. have mesenchymal cells that will create The perichondrium produces a thin collarOsteo its Monavas - of bone around the shaft of the cartilage / chondrocytes tes model and is referred to as periosteum ↓ messenchyal enlarge bis formed a to cells bone around create It chondroblasts  Endochondral Bone Formation (Continued) The chondrocytes in the center of the cartilage model become larger (hypertrophy) and the surrounding cartilage matrix becomes calcified. These chondrocytes undergo programmed death leaving behind cavities within the cartilage matrix.  Endochondral Bone Formation (Continued) Blood vessels and osteoblasts and osteoclasts from the periosteum (periosteal buds) migrate into the cavities within the calcified cartilage matrix. The calcified cartilage breaks down but before doing so provides a surface on which osteoblasts can produce spongy bone. things happening This then becomes a primary ossification at same time center.  Endochondral Bone Formation (Continued) As osteogenesis continues in the primary ossification center, a cavity results as the bone is remodeled. This central cavity is called the marrow medullary cavity. Further growth involves an increase in both he length and diameter of the bone. (pumanly through appositional growth  Secondary Center of Ossification Secondary atossification end of bone centers appear in the epiphyses in a manner similar to that described above for the primary ossification center. forms more spongy bone This occurs shortly after birth  Remaining Cartilage By the time the fetal skeleton is fully formed, cartilage only remains at the uyaline joint surface as articular cartilage and between the diaphysis and epiphysis as the epiphyseal plate The epiphyseal plate is responsible for the longitudinal growth of bones. at ends of bones particular cartilage was there from ocartilage beginning of bone formation  Grow in Length The epiphyseal plate is the area of growth in a long bone. n length It is a layer of hyaline cartilage where ossification occurs in immature bones. On the epiphyseal side of plate, cartilage is formed. On the diaphyseal side, cartilage is ossified, and the diaphysis grows in length. The epiphyseal plate is composed of four zones  epiphysa Growth in length continued 1. reserve zone: is the region closest to the epiphyseal end and contains hyaline cartilage. much 2. proliferative zone: is the next layer toward the as diaphysis and contains stacks of slightly larger adding alsroving start dividing chondrocytes. chondrocytes bes stacking onto each other grow grow 3. Hypertrophy zone: contain chondrocytes that are while maintaining larger than those in the proliferative zone. size of growth 4. zone of calcification/resorption: the zone closest to plate the diaphysis becomes calcified. The bone increases in length as long as the rate of cartilage production equals the rate by which it is replaced by bone.