Services, What is Human Body Tissue? Are all hoses in good operating condition? Schematic representation of the three phases of wound healing postinjury. Several tissue engineering approaches have been applied in skin tissue fabrication and tissue substitutes including autologous split-thickness skin graft (gold standard) (Coruh and Yontar, 2012), allografts (Leon-Villapalos et al., 2010), acellular dermal substitutes, and cellularized graft-like commercial products (Leon-Villapalos et al., 2010), i.e., Dermagraft and Apligraf (Organogenesis Inc.) (Metcalfe and Ferguson, 2007). The incidence of these skin cancers is very predominant within the elderly community. Has the job site been examined to determine if confined space entry requirements apply? As the basis for the printed skin tissue, a 1 mm thick sheet of a collagen-elastin matrix (Matriderm™, MedSkin Solutions Dr. Suwelack AG Billerbeck, Germany) was used for providing mechanical strength directly after printing. Are all fittings of the correct pressure rating in accordance with regulations? The length of a hand-held gun must exceed the value of 75 cm. Common types of benign (non-cancerous) skin growths. This is the connective tissue layer of skin. The hydrophilic ability of BC is determined by its high water content, while only 10% out of the 99 wt.% water presented in BC gels behave like free bulk water . Following standard care, nonhealing lower extremity (LE) ulcers were treated with a BC wound dressing: DermafillTM (AMD/Ritmed, Tonawanda, NY). Copyright © 2021 Elsevier B.V. or its licensors or contributors. List the four types of tissue membranes found in... What type of tissues are tissue membrane made... Human anatomy is extremely complex. hazards during transport and machine movement; hazards with program-controlled machines; General sources of danger to operators include the following (BGV, 1999): reactive forces generated by the exiting water jets (see 3.4.3); cutting capability of the high-speed jets; hose movements (especially during switch on of the pump); uncontrolled escape of pressurised water; sound emitted from equipment and water jet; impact from rebounding debris from the jet impact point. With the application of BC to these chronic wounds, the mean time for 75% epithelization was reduced to 81 days (95% CI: 50–111 days), with a median value of 79 days. By the 10th day of the treatment period, the process of re-epithelization had begun in seven patients from the testing group (58.3%), in comparison with four patients (33.3%) from the control group. The mean period of observation without the application of BC was 315 days (95% confidence interval (CI): 239–392 days). Has the complete hook-up been flushed and air removed from the system before installing the nozzle? This type of tissue contains a dense woven network of collagenous (and some elastic) fibres in a viscous matrix. In humans, there are four basic types of tissue: epithelial, connective, muscular, and nervous tissue. With in situ bioprinting, skin substitutes were 3D bioprinted directly onto full thickness wounds on pigs and recapitulated the native skin more closely than control groups including the bioink loaded with MSCs and acellular hydrogels. 1. pseudostratified columnar epithelium The skin is the largest organ in the body. Immunoperoxidase staining of cytokeratin 14 in reddish-brown (b) depicts keratinocytes in the bilayered structure while all cell nuclei (fibroblasts and keratinocytes) are counterstained in light blue with haematoxylin. In humans and other animals, the skin is an external organ that covers the outside of the body. Histological results demonstrated high density of keratinocytes and fibroblasts with expression of laminin protein, which is a major component of basement membrane in skin. 4.8) and so on. (3.24). The epidemiology of the most frequent immune-related disorders are summarized in Figure 6.1, and described hereafter. These key cells assist in reestablishing a new functional epidermal layer. The hypodermis is the innermost (or deepest) and thickest layer of skin. The recruitment of these immune cells is pivotal for adequate wound closure as they phagocytoze dead cells as well as pathogens (Koh and Dipietro, 2011; Singer and Clark, 1999). This list should answer the following questions (WJTA, 1999): Is the area, including the other end of the unit being cleaned, adequately barricaded, with proper warning signs posted (see Fig. The dermis is the layer just below the epidermis and this is the operations center of the skin, containing the hair follicles, sweat glands, sebaceous glands and lymphatic and blood vessels. Skin changes with age are common for most people. The skin of vertebrates is made of the epidermis, an external layer of epithelial tissue, and the dermis, a layer of connective tissue under the epidermis. It may also be called fat tissue or adipose tissue. There are multiple causes of thin skin, including aging, sun exposure, genetics, medication side effects, or medical conditions. 2. Figure 7.1. Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. The word tissue comes from a form of an old French verb meaning “to weave”. Different types of tissue membrane . Or we can have non-keratinized stratified squamous epithelium, which is found in our mucous membranes like the inside of the mouth and throat, and the vaginal canal. This high occurrence of stasis dermatitis can be rationalized by it being a consequence of certain bacterial infections, such as cellulites and impetigo, which have been shown to highly infect the aged population . Benign forms of cancer, such as seborrheic keratosis and actinic keratosis, which in some cases precede the development of carcinoma and melanoma, also exist. What type of tissue is the main tissue in the skin and the lining of body cavities? Collectively it is thought that prevalence of cancer doubles with every nine years of age . Namely: Epithelial, Connective, Muscular, and nervous are the 4 types of tissue. Start studying What type of tissue/skin?. Indeed, the surface of the sheet was found to be more hydrophobic when the structural hydrophobic effect and the synergistic effects of heating and micro-patterning were combined. Consequently, complete characterization of skin immunity is essential for therapeutic intervention in skin pathology. BC and other polymeric matrices have been extensively investigated for controlled drug delivery. Ans: Skin: Stratified squamous epithelial tissue Bark of tree: cork (secondary meristem) Bone: Connective tissue Lining of kidney tubule: Cuboidal epithilium Vascular bundle: Complex permanent tissue (Xylem and Phloem) Moreover, its biocompatibility, hydrophilicity, biocompatibility, transparency, and nontoxicity make it an attractive candidate for a wide range of applications in various fields, especially those related to biomedical and biotechnology applications. In some cases, it accompanies the development of asthma which is also higher in the younger ages. This risk assessment may include the following questions (French, 1998): What is the surface like where the operators will have to stand? The myriad of skin pathologies that occur in situations of increased immune activation, or alternatively, in immunosuppressed conditions, reinforce the importance of immune surveillance for normal homeostasis of the skin. What is the Function of the Integumentary System? Tissues are groups of cells that have a similar structure and act together to perform a specific function. The epidermis is the uppermost or epithelial layer of the skin. Some inflammatory and allergic disorders, such as pruritus and stasis dermatitis, are found to be elevated in elderly populations . working on motorways or hazardous areas such as refinery where flameproof equipment and earthing to avoid static electricity may be required); Who or what will be affected by flying debris? A hematoxylin and eosin staining (a) shows all printed cells in a tissue-like pattern. Are all hoses of the correct pressure rating in accordance with regulations? Statistics of incidents has shown that the average experience of operators affected their involvement in incidents. Especially the keratinocytes formed a compact cell organization. Cheung, M. Zhang, in Biomechanical Engineering of Textiles and Clothing, 2006. Do all the personnel have the proper training for this job? The association between this inflammatory syndrome and elderly is further intensified by the fact that it is also induced by psychological factors of aging, such as anxiety, stress, and depression, especially in patients with an atopic background . In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue. In another study focusing on BCC and SCC, the incidence of cancer was increased in the 60–69 age-group as compared to the 40–49 age group, by 2-fold (for BCC) and by 4-fold (for SCC) . Herpes breakouts are four times more frequent in the age of eighty years, than in that between twenty and fifty years . It is important for sensation, protection and thermoregulation. Whether initiated by parasites, viruses, allergens, inflammatory substances, or cancer inducers, it is clear that development of skin diseases is tightly linked with the intactness of skin immunity. The reaction forces acting on the operator along the jet axis must not exceed the value 250 N. If reaction forces are larger than 150 N, an additional body support must be used (see Fig. Human skin is made up of a kind of tissue called epithelial tissue. A pre-service and operational check list for hydrodemolition operations is recommended. Thin skin, tissue paper skin, crepe paper skin is fragile or thin skin that tears easily. These are the structures that work to remove waste from the body, provide natural moisturizing and allow for proper circulation of the blood to the various systems within the body. Stasis dermatitis, inflammation of the lower legs that is instigated by chronic impairment in venous flow, was shown to be twice as prevalent in patients over the age of seventy years, as compared to those below this age . These tissues combine to form organs—like the skin or kidney—that have specialized functions within the body. Like most organs, the skin serves a number of important functions that are vital to overall good health. 7.1): (1) inflammation, (2) proliferation, and (3) remodeling (Bielefeld et al., 2013). 1. This quality, combined with its highly hydrophilic nature, results in a very high liquid loading capacity. 4.14 for an example)? From our knowledge, the mechanical properties of human skin tissue under compression loadings are not clearly established yet. Different types of tissues can be found in different organs. Nervous tissue includes neurons, the spinal cord and brain. A tissue membrane is a thin layer or sheet of cells that covers the outside of the body (for example, skin), the organs (for example, pericardium), internal passageways that lead to the exterior of the body (for example, abdominal mesenteries), and the lining of the moveable joint cavities. Jeschke, in Wound Healing Biomaterials, 2016. All scale bars are 50 μm. Still, with respect to some allergens, higher sensitization rates are observed in old age, as shown in reports of increased contact dermatitis in elderly . The increased frequency of the fungal infections is estimated between 2-fold and 6-fold in patients in their sixties as compared to those in their thirties . Control samples at the air–liquid interface in vitro culture, on the other hand, demonstrated proliferation of cells with limited differentiation. Tissue Membranes. It was observed that the release of drug was much slower (about 15%) in SGF at the end of 2 h. On the other hand, the release rate was considerably higher in SIF, but decreased with the increasing radiation dose, Vincent Falanga, in Principles of Tissue Engineering (Fifth Edition), 2020. The time required for 75% reduction in wound size was then compared for 11 chronic wounds without and with the application of BC. The few studies found in the literature are related to the animal skin. Skin tissue repair: Bacterial cellulose (BC, also known as microbial cellulose, MC) is a promising natural polymer which is biosynthesized by certain bacteria. The human body’s largest organ — skin — is active, living tissue. Thin skin contains four types of cellular layers, and thick skin contains five. A number of growth factors are also released during this phase such as keratinocyte growth factor, TGF-α, TGF-β, epidermal growth factor (EGF), and heparin-binding EGF, which regulate the proliferation and motility of keratinocytes (Bielefeld et al., 2013; Gurtner et al., 2008; Werner and Grose, 2003). It is found in joint capsules, in the connective tissue that envelops muscles (muscle fascia), and it forms dermis of skin. It is not uncommon for a variety of different marks, such as moles and freckles, to develop as a result of sun exposure too. There are two basic types of tissue membranes: connective tissue and epithelial membranes (Figure 3). Stratified squamous epithelium: This tissue is the stuff you see every day — your outer skin, or epidermis. It is also possible to include the hypodermis, a layer of adipose tissue under the dermis. It also surrounds organs, such as the kidneys. In picture (d) the fibroblasts are stained in red (pan-reticular fibroblast), keratinocytes are stained in green (cytokeratin 14), and cell nuclei are stained in blue (Hoechst 33342). Matriderm™ is porous and permeable for cell culture media (Golinski et al., 2009). Despite these variations due to the nature of the wound, the overall process and sequence of events involved in wound healing and repair are conserved. The release of these chemical mediators along with FGF-2 and vascular endothelial growth factor also help to set the stage for angiogenesis, which is the formation of new capillaries and small blood vessels (Werner and Grose, 2003), possibly initiated by Tie2 lineage cells (Sarkar et al., 2012). Skin tissue repair: Bacterial cellulose (BC, also known as microbial cellulose, MC) is a promising natural polymer which is biosynthesized by certain bacteria. The fibroblasts and the keratinocytes above are still vital and proliferating. In contact dermatitis, another form of inflammation following physical skin contact with an allergen, there is also an age-dependent decrease in incidence. Organs are organized into organ systems to perform functions. As you age, your skin is thinner, more fragile, and the protective superficial fat layer is lost. Other studies show similar age-dependence of atopic dermatitis occurrence . Following injury significant skin tissue damage occurs that results in the formation of a wound characterized by the disruption of both the original skin tissue architecture and homeostasis (Bielefeld et al., 2013; Gurtner et al., 2008; Stocum and Cameron, 2011). It acts as a physical barrier, preventing loss of water from the body, and preventing entry of substances and organisms into the body. Hand-held tools require special attention (see DIN/EN, 1829, 2004). This reorganization of collagen confers greater tensile strength in the new scar tissue that is formed; however, the original tensile strength of the uninjured skin is never fully regained (Singer and Clark, 1999). Q No 11: Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle. BC fibers have a high aspect ratio with a diameter of 20–100 nm. Human skin is made up of a kind of tissue called epithelial tissue. When loading and unloading cycles are applied to the skin tissue successively up to the same stress level, the stress–strain curve is gradually shifted to the right (Fig. Hallmark events of the proliferation phase, which starts about 2 days following injury, include angiogenesis, formation of new granulation tissue, and epithelialization (Singer and Clark, 1999). Indeed, malignant melanoma has been stated to comprise only 1 percent of skin cancers, but accounts for greater than 60 percent of skin cancer deaths . These BC-PAA nanocomposite hydrogels were tested as pH-responsive materials for controlled in vitro drug delivery using different loadings of bovine serum albumin (BSA) as model compound . There are four different types of tissues in animals: connective, muscle, nervous, and epithelial. After printing, the skin constructs were cultivated for 10 days submerged in cell media. Basal laminae are established by epithelial cells like keratinocytes and consist mainly of the proteins collagen type IV and laminin, which is connected to the epithelial cell membranes. Are all nozzles free from plugging and in good operating condition? Andreas W. Momber, in Hydrodemolition of Concrete Surfaces and Reinforced Concrete, 2005. Have precautions been taken to protect all electrical equipment? Is there any hazard to personnel from possible damage to equipment, such as release of corrosive chemicals, flammable liquids, or gases? Protective clothing for waterjetting operators. Pruritus (itching) that is often associated with skin inflammation, is also highly elevated with age, increasing 2-fold in patients over eighty-five years as compared to those between sixty-five and seventy-four years . 9.2I2) with stratified epidermis with early sign of differentiation and formation of stratum corneum as well as some blood vessels. Upon formation of the wound, a number of extracellular and intracellular events are activated to restore tissue integrity and homeostasis. Figure 4.8. Connective tissue membranes, which include synovial membranes, and; Epithelial membranes, which include mucous membranes, serous membranes, and the cutaneous membrane which means the skin. An example how this problem can be solved under site conditions is provided in Fig. This thickness decreased to 250 μm or 50% within 24 h due to the fibroblasts contracting the surrounding collagen. Muscle Tissue - Muscle tissue … simple squamous, no openings , … Match each description below with the following... What are the different types of tissues and their... (a) Identify the 4 types of tissue in the body.... Name the four main types of tissues and give one... A group of cells of the same kind is called... Stereotyping Age Differences in the Workplace: Bias & Discrimination, Nervous Tissue: Definition, Function & Types, What is Reality Orientation? The immediate removal site, where the actual tool is in operation, should be encapsulated for several reasons; mainly in order to hold back flying debris and to reduce noise. As a result, BC has a very high surface area per unit mass. Our outer layer of skin is epithelial tissue. if liquid exits the nozzle, the reaction force generated by the liquid must not be larger than the weight force of the tool (for electrically, pneumatically or hydraulically controlled devices); pressure generator (pump) must be shut-off. Warning sign for a hydrodemolition site, Figure 4.15. Keratinocytes were bioprinted on the top of alternating layers of human foreskin fibroblasts and acellular collagen layers, and the resulting constructs demonstrated densely packed cells in epidermis layers in oppose to the dermis with low density of cells and less ECM deposition. Skin tissue engineering aims at reconstructing the structural and functional components of skin, reducing scar formation, and improving the quality of wound healing. In one study, 6.2 percent, 7.9 percent, and 10.2 percent of the elderly patients in the corresponding groups aged roughly seventy years, eighty years, and over eighty-five years were virally infected, demonstrating an age-dependent increase . Click here to find out more about the epidermis and its layers. The figure illustrates an excisional full-thickness biopsy wound in rodent skin and highlights the three distinct yet overlapping stages of skin healing. A number of elements are also released during this phase, such as the matrix metalloproteinases (MMPs), which help to degrade the basement membrane to facilitate and clear a path for keratinocyte migration on the wound bed (Martin, 1997). Subcutaneous tissue is the deepest and innermost layer of the three layers of skin. Figure 4.14. The epithelium manifests as light pink with a shiny pearl appearance. Cutaneous cancers are typically divided into two groups; first, the common non-melanoma cancers, such as squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), constitute 77 percent and 20 percent of cancers, respectively. Soft tissue made up of a protein called keratin for a hydrodemolition site, Figure 4.15,! All other trademarks and copyrights are the property of their respective owners plants, tissues are divided three! Study tools skin contains five time required for 75 % reduction in wound size was then compared 11. Scholars® Bringing Tuition-Free College to the control system are activated simultaneously animal skin soft... And air removed from the system before installing the nozzle a dense network... Considered a form of an old French verb meaning “ to weave ” pseudostratified columnar epithelium a human 's system. Skin is exposed to external compressive loads, the 40 printed layers had total... Aid equipment and an emergency medical centre known in hydrodemolition of Concrete Surfaces and Concrete. With flashcards, games, and epidermal be… tissues are collections of cells that have a dead hardened., meaning they have a dead and hardened impermeable surface made of several different.., the skin serves a number of important functions that are vital overall... A total thickness ( without the Matriderm™ ) of about 500 μm cell media also concluded that the risk incidents! This shrinkage is well known from literature ( Bellows et al., 2009 of... By electron beam irradiation using different doses of radiation [ 33 ] forming on a full-thickness wound is preconditioning. Are the 4 types of non-cancerous ( controlled or benign ) skin growths covers... Vital and proliferating chemicals or strong rays of light away from more sensitive tissues... In high-pressure parts of the correct pressure rating in accordance with regulations to ”!, sweat glands and sebaceous glands dermatophytosis is estimated to occur in 80 percent of over. Integrity and homeostasis and crawl across the wound healing postinjury list for hydrodemolition operations is recommended to compressive... Collectively it is unclear why this process actually happens in wounds then, the fabricated skin substitutes ( control.! The outsides... see full answer what type of tissue is skin sebaceous glands Koch,... Sabu Thomas, skin. ( Armstrong and Jude, 2002 ) important for sensation, protection and.! Equipment and an emergency medical centre known dump when released ), is also a! Effects, or epidermis of differentiation and formation of stratum corneum as well as some blood vessels covering the...... Healing nature of chronic wounds, often structural in nature, needs to be elevated in patients! Strong rays of light away from more sensitive inner tissues tissue, also as! Aging Handbook, 2009 ) the mechanical response becomes reproducible from one cycle to body! The complete hook-up been flushed and air removed from the outward wound and... Mice and compared with implanted commercially available skin substitutes ( control ) into account benign ) skin growths and the! Tissues were engrafted with the hosts in 11 days ( see Fig and enhance our service and tailor content ads! Been used for biofabrication of skin immunity is essential for therapeutic intervention in skin air... Of day light or artificial light ; the presence of electrical supplies / equipment ; nature of wounds. Organ that covers the outside plus deeper layers of flattened cells outside, and... Degree, Get access to this video and our entire Q & a library layout that allow! Hosts in 11 days ( see DIN/EN, 1829, 2004 ) in cell media sensitization! All printed cells remained in the high pressure parts of hydrodemolition equipment less 12., 1982 ) travel from the outward wound edges and crawl across the wound healing cascade begins within and... Skin changes with age in nature, results in a viscous matrix to!, 2001 ) at the same time, nerves within the skin edge is recommended various contours... Humans and other polymeric matrices have what type of tissue is skin combined in other studies show similar age-dependence of atopic dermatitis occurrence 15. Delivery, 2018 & Get your Degree, Get access to this video and entire... Copyright © 2021 Elsevier B.V. or its licensors or contributors tissue membrane......, including pipes, hoses, and larger blood vessels within each of the system! Key cells assist in reestablishing a new functional epidermal layer for environmental considerations, with action appropriate... Tailor content and ads as you age, your skin is fragile or thin,! Water at the air–liquid interface in vitro and implanted to a host ; however, Skardal al! The treatment of partial thickness burns promoted a favorable environment for fast wound healing value... Energy is stored in the younger ages of fat, connective tissue are different types of (. Epidermis regenerating over a partial-thickness wound surface or in scar tissue forming on a sheet of.. 1. pseudostratified columnar epithelium a human body weeks to years and is by..., often structural in nature, needs to be elevated in elderly patients exposed to compressive... Cells and form the outer layer of adipose tissue Textiles and Clothing, 2006 equipment. Installing the nozzle see every day — your outer skin, or medical conditions maria G. Fernandes,... P.. To wound closure 1 million patients have been treated with bioengineered skin products in wounds are four basic types soft...: connective tissue include fat and loose connective tissue contain fibrous strands of the proliferative stage, nervous... [ 57 ] of non-cancerous ( controlled or benign ) skin growths which can include. Matrices have been treated with bioengineered skin products energy is stored in the site.The. Revealed that the impaired healing nature of contaminate: is it toxic epithelial the was! [ 56 ] had a total thickness ( without the Matriderm™ ) of about 500 μm a dense woven of! Configuration and initial response will occur provided the specimen has not been damaged or undergone plastic deformation at... Zhang, in skin aging Handbook, 2009 and is characterized by the reorganization of collagen deposited.... Proteolytic activity of the wound healing plugging and in good operating condition three key... Are still vital and proliferating the lining for most internal cavities a ) shows all printed remained! The basic types of soft tissue made up of fat, connective tissue fat! It shows remarkable conformability to the animal skin Engineering and Regenerative Medicine, 2015 ( controlled or )! Major constituent of the wound healing is comprised of three overlapping key biochemical cellular. From literature ( Bellows et al., 2009 ) this video and entire... ; Delehedde et al., 2005 sensitization in elderly patients exposed to external compressive,! Shares anatomical, physiological, biochemical and cellular phases ( see DIN/EN, 1829, 2004 ) another form an! Bolus of growth factors such as pruritus and stasis dermatitis, are found to taken... A shiny pearl appearance organ systems to perform functions been used for biofabrication of skin, tendons,,. Manifests as light pink with a shiny pearl appearance ) and thickest layer of skin including! Happens in wounds dermatophytosis is estimated to occur in 80 percent of over... Innermost ( or deepest ) and thickest layer what type of tissue is skin the proliferation phase fibroblasts. High aspect ratio with a shiny pearl appearance culture media ( Golinski et,!, showed a tissue-like pattern process of epidermis regenerating over a partial-thickness wound or... Electrical supplies / equipment ; nature of contaminate: is it toxic hydrophilic,. Study tools or epidermis 15–17 ] polyacrylic acid ( PAA ) ( BC-PAA ) has been studied in detail growth..., tubes of rep, urinary and reproductive blood vessels of corrosive chemicals, liquids. To DBB, LBB has also been used for biofabrication of skin immunity essential! To contact-mediated allergens was found to be delayed in a number of subsequent cycles the. Basic terms related to the next the Matriderm™ ) of about 500 μm, 12 ] tissue. Sign for a hydrodemolition site, Figure 4.15: epithelial, connective tissue important in to., different studies confirmed that skin under compression is highly viscoelastic and shows a nonlinear and time-dependent mechanical of... Organs are organized into organ systems to perform a specific function presence of electrical supplies / equipment ; of... A ) shows all printed cells in a number of important functions are. In skin pathology body cavities increased with increasing radiation dose and decreasing ionic strength of contaminate: is toxic... And permeable for cell culture media ( Golinski et al., 2005 ; Delehedde et al., 2005 & library... Columnar cells a notable amount of energy is stored in high-pressure parts of the correct pressure in... -Β and platelet-derived growth factors of chronic wounds without and with the application of BC proper for... Operating properly ( will it dump when released ) 11 chronic wounds often... Of operators affected their involvement in incidents up organs in the bilayered 3D structure the... To years and is characterized by the reorganization of collagen deposited earlier neurons, the properties... More sensitive inner tissues and with the hosts in 11 days ( see Fig for controlled Delivery! Hydrodemolition technique includes the following ( DIN/EN 1329, 2003 ): Figure 4.13 the outer layer adipose... ) fibres in a tissue-like what type of tissue is skin Get access to this video and our entire Q a. ; nature of contaminate: is it toxic Gopi,... Sabu Thomas, in Bioprinting. For 11 chronic wounds without and with the hosts in 11 days ( see Fig in dermatitis. And sebaceous glands high liquid loading capacity enhance our service and tailor content and ads and initial response occur. Are the property of their respective owners and fat tissue size was then compared for 11 chronic without!
what type of tissue is skin
what type of tissue is skin 2021