NURS 207 (N01) Tissue-Epithelial & Connective Tissues (Sept 19, 2024) PDF

NURS 207 (N01) Tissue level of organization Tissues: Epithelial and connective tissues Reading materials (textbook): Tortora, 16th ed., Ch. 4 September 19, 2024 Dr. P. Lee  Objectives 1) Name the four ba...

NURS 207 (N01) Tissue level of organization Tissues: Epithelial and connective tissues Reading materials (textbook): Tortora, 16th ed., Ch. 4 September 19, 2024 Dr. P. Lee  Objectives 1) Name the four basic types of tissues that make up the human body 2) State the characteristics of each the four type of tissues 3) Describe the classification and features of epithelial, connective, muscular, and nervous tissues 4) State the main differences between epithelial and connective tissues  Tissues (colony of aggregated cells) Diversity of cells Diversity of tissues Four basic types of tissues: ✓ The structural variation of various tissues are usually related to their physiological functional  Four basic types of tissues 1) Epithelial tissue Sheets of cells form surface lining that cover our body, hollow organs, body cavity, and ducts Forms the barrier between our internal and external environment Can also function as glands for secretion 2) Connective tissue Compose of cells and extracellular matrix → Extracellular matrix are mixture of protein fibers and ground substance → Ground substance is one component of connective tissues that binds the cells together  Four basic types of tissues 3) Muscle tissue Can contract and generate either tension or force Heat is generated during the muscle contraction Are excitable cells (exhibit electrical excitability) Nucleus Skeletal muscle Muscle fiber (cell) Striations Nucleus Muscle fiber Cardiac muscle Intercalated disk Striations Nucleus Smooth muscle Muscle fiber  Four basic types of tissues 4) Nervous tissue Can response to stimulus (or stimuli) by generating and conducting an electrical impulse (action potential) Action potential generated can be transmitted to target tissue → An response will be elicited by the target tissue ▪ Response is proportional to the initial stimulation ▪ Can either be excitatory or inhibitory ▪ To coordinate body activities  Four basic types of tissues 4) Nervous tissue Composed of excitable cells (electrical excitability) → Nervous system can be sub-divided into 2 systems Central nervous Peripheral nervous system (PNS) – 3 subunits system (CNS) Autonomic nervous system Somatic Nervous System (involuntary control) (skeletal muscles) Enteric nervous system (gut)  Epithelial tissue Continuous sheets of cells that form the protective barrier for our body systems → Can be single or multiple layers → With tight junctions between neighboring cells, limiting the diffusion of solutes and fluids around the epithelial cells → With various shapes and forms as well as function → Has its own nerve supply → Avascular (no capillary blood supply) ▪ Nutrient supply and waste removal rely on its neighboring connective tissues though diffusion  Classification of epithelial tissue 2 general types according to their function a) Covering and lining epithelium → Single layer → Multiple layers  Classification of epithelial tissue b) Glandular epithelium → With the secreting cells within the lining structure (i.e. function as secretion gland) e.g.) Intestine e.g.) Upper airway ✓ With microvilli to increase ✓ With cilia to remove the surface area for absorption debris ✓ And goblet cell for mucus ✓ With goblet cell for secretion mucus secretion  Classification of epithelial tissue Two general types according to their arrangement of cells into layers and their shape of the cells: 1) Arrangement (3 subtypes) a) Simple epithelium → Single layer → Capable of transporting both the solvent and solutes by diffusion and osmosis → Also associated with absorption (from external environment to body compartment) and secretion (from body compartment to external environment)  Classification of epithelial tissue b) Pseudostratified epithelium Nuclei → Also a single layer epithelium → With cell nuclei located at different levels of the tissue → May contain microvilli and cilia on the apical surface (surface facing external) ✓ Also may contain goblet cell for mucus secretion  Classification of epithelial tissue c) Stratified epithelium → With two or more layer of cells → Function for protecting underlying tissues from wear and tear (e.g. skin)  Classification of epithelial tissue 2) Shape of the cells (4 subtypes) a) Squamous cells → Thin and flat → Allow easy passage for substance passing through them b) Cuboidal cells → Wide and shape like cubes → May contain microvilli and function in either secretion or absorption  Classification of epithelial tissue c) Columnar cells → Shape like a columns which is tall, but not much in width → May also contain microvilli or cilia and function in either secretion or absorption d) Transitional cells → Type of stratified epithelium with shape may change, depending on the physiological condition → Shape can be altered when they are being stretched and then collapsed back and forth (e.g. epithelial lining of the bladder)  Connective tissue Most abundant and widely distributed in the body with various forms and functions With 2 main components: 1) Cells  Connective tissue 2) Extracellular matrix (protein fibers and ground substance) that surround the cells  Various functions of connective tissue 1) Protect → Protect against intruders e.g.) Macrophages as an effective type of phagocyte 2) Support → Structural support e.g.) Osteocytes as the major cell type in bone  Various functions of connective tissue 3) Connection and bind → Form a matrix that hold the organs in place e.g.) attaching epithelial tissues to underlining tissues (binding the skin and muscle loosely together) or) Tendon (muscle to bone), ligament (bone to bone) 4) Transport → Transport of nutrients and gases e.g.) Blood plasma 5) Immunity → Protect the body from invaders e.g.) leukocytes (white blood cells)  Common features of connective tissue All connective tissue compose of cells and extracellular matrix Extracellular matrix forms a medium that surround the cells → Could be soft (adipose tissues) or hard (bone) Extracellular matrix has 2 components: → Extracellular fibers and ground substance Usually is highly vascular, except: → Cartilage (avascular – no blood supply) → Tendons (poor blood supply) Usually with nerves (except cartilage)  Various types of cells in connective tissue 1) Fibroblasts → Present in all the general connective tissues → Move through the connective tissue and secrete intracellular fibers and ground substance within the matrix 2) Macrophages → Type of phagocytes that develop from monocytes → Perform phagocytosis at sites of infection or inflammation  Various types of cells in connective tissue 3) Plasma cells → Type of white blood cells that produce antibodies → Part of the immune system 4) Mast cells → Type of blood cells involve in inflammatory response → Can bind to, ingest, and kill bacteria 5) Adipocytes → Fat tissues → Energy storage  Various types of cells in connective tissue 6) Leukocytes → White blood cells → Part of the immune system 7) Osteocytes → Involved in bone formation → With very dense extracellular matrix 5) Chondrocytes → Found in cartilage → Produce and maintain the cartilaginous matrix  Various types of fibers in extracellular matrix within the connective tissue Function to strengthen and support connective tissues (3 kinds) 1) Collagen fibers → Strong and resist pulling or stretching → Often occur in parallel bundles 2) Elastic fibers → Form a fibrous network within a connective tissue → With ability to return to their original shape after being stretched, a property called elasticity  Various types of fibers in extracellular matrix within the connective tissue 3) Reticular fibers → Form a meshwork of thin stranded fibers → Provide support to tissues such as spleen, lymphatic system, liver etc.  Ground substance in extracellular matrix within the connective tissue Ground substance is extracellular substance of connective tissue between the cells and fibers → Contains water and a variety of large organic molecules → may be fluid, semifluid, gelatinous, or calcified → Compose of a mixture of polysaccharides and proteins ▪ The mixture of polysaccharides is collectively referred to as glycosaminoglycans (GAGs) → Provide a medium for exchange between blood and cells  Classification of connective tissue 2 main types: → Embryonic connective tissue → Mature connective tissue 1) Embryonic connective tissue → With mesenchyme and mucous connective tissue ▪ Mesenchyme are found primarily under skin and along the developing bones of embryo ▪ Mucous connective tissue found mainly in umbilical cord of fetus  Classification of connective tissue 2) Mature connective tissue a) Loose connective tissue → With fewer fiber proteins (especially collagen fibers) in the extracellular matrix → Mostly in the form of areola connective tissue → Mainly for bind and support b) Dense connective tissue → With more fiber proteins in the form of collagen and are more densely packed → Forms the supportive framework  Classification of connective tissue 2) Mature connective tissue c) Cartilage → Consists of a dense network of collagen fibers and elastic fibers → Strength of cartilage is due to its collagen fibers d) Bone tissue → Extracellular matrix consist calcium and phosphates which give bone its hardness and compressive strength → With collagen fibers, which give bone its tensile strength  Classification of connective tissue 2) Mature connective tissue e) Liquid connective tissue → Has a liquid as its extracellular matrix → e.g.) Blood is the liquid connective tissues has a liquid extracellular matrix called blood plasma and formed elements which are red and white blood cells  Sample questions 1) Which type of epithelial tissue forms the skin? a) Simple squamous epithelium b) Stratified epithelium c) Simple columnar epithelium d) Simple cuboidal epithelium 2) Which type of epithelial tissue lines the airways and intestine that is able to secrete mucus? Select the best answer. a) Ciliated glandular epithelium b) Ciliated simple columnar epithelium c) Non-ciliated pseudostratified epithelium d) Non-ciliated simple columnar epithelium  Sample questions 3) In which area would transitional epithelial cells be found? a) Lining of the airways b) Outer layer of skin c) Lining of the urinary bladder d) all of these choices are correct 4) The extracellular matrix of connective tissue consists of: a) enzymes and membranous organelles b) plasma membranes and ground substance c) calcified crystals of minerals and enzymes d) protein fibers and ground substance  Sample questions 5) The extracellular matrix of blood is: a) plasma b) red blood cells c) white blood cells d) connecting fiber find inside the blood vessels 6) Which of the following is a good example of dense connecting tissue? a) adipose tissue b) blood plasma c) heart muscle d) bone  Answer to sample questions 1) b 2) a 3) c 4) d 5) a 6) d