Chapter 5 Tissues BMS - Williams, smith, Fitzgerald - book notes PDF

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Williams, smith, Fitzgerald - book notes...

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Chapter 5 / Tissues The human body has 4 types of tissues:  Epithelial - covers the body, lines all the cavities, and composes the glands.  Connective - connects the structures of the body, provides structural support, and holding organs together. STRETCHY & STRONG! Maintains body’s integrity.  Muscle - provides movement and heat  Nervous - responds to the environment by detecting, processing, and coordinating information Epithelial Tissues  Composed of cells laid together in sheets- strong cell to cell attachments hold the cells together. o One side of the cell is oriented towards the surface of the tissue either the body cavity or external environment — may have cilia or microvilli (small hair like folds of the cell membrane that increases the cells surface area for absorption) o The other side is joined to deeper connective tissue at the basement membrane.  This layer is an acellular membrane, composed of collection of polysaccharides and proteins that help to cement the epithelial tissue to the underlying structure  Epithelium tissue is recognized by the number of cell layer, and the shape of the cells in the upper layer. o There are total of eight basic types of epithelium….  Six of them are identified by number of cells and their shapes.  Transitional and Pseudostrafied are named for the types of cell found in them.  Simple Epithelium – one layer of cells, usually functions as a diffusion or absorption membrane.  Lining of blood vessels and respiratory membrane of your lungs.  Stratified Epithelium – many layers of cells and is designed for protection.

Found in outer layer of skin, and ducts of salivary glands.  Squamous Epithelium – flattened cells, fried egg like, they are thin enough cells that form a membrane through which compounds can move via diffusion.  Cuboidal and Columnar Epithelium – usually plumper and composed mucous membranes in which the cells secrete mucus and other compounds. o Glands are composed of epithelial tissue, and classified by how they secrete and release.  Glands that secrete into ducts are exocrine.  Salivary glands, and sweat glands o Each secretes its products into a duct that directs the secretion to the surface of the gland.  Glands that secrete into extracellular fluid surrounding the gland are endocrine. They have no ducts.  They secrete hormones that are then picked up by the bloodstream and carried throughout the body. o Adrenal, thyroid, and pituitary glands Connective Tissue  Connects bodily structures. It binds, supports, and anchors the body and is the most abundant type of tissue in the body.  Composed of cells suspended in a non-cellular matrix (the matrix or ground substance is secreted by connective tissue cells, and determines the characterizes of the con. tissue).  All connective tissue includes cells that produce protein fibers ( fibroblasts), cells that store fat (adipocytes), and cells that patrol the tissue for invaders (macrophages). o Each type has specialized cells that produce specific matrix. They can be liquid, gel-like, or solid. 

 The ground substance for all connective tissue is collagen and elastin ( flexibility, stretch and recoil). o Collagen is one of the main components of all connective tissue, and consequently is the most abundant protein in the animal kingdom. o The classification of connective tissue is either soft connective tissue or specialized connective tissue. o Soft- skin, tendons, blood vessels. o Specialized- cartilage, bone, blood, and lymph.  Soft Connective Tissue o Has a matrix that is composed of semifluid substance. o Also, contains fibroblasts that secrete fibers and white blood cells that fight infections. The fibers in the matrix can be either loosely arranged or densely packed.  Loose connective tissue is also called areolar connective tissue.  Dense connective tissue includes dense irregular tissue of the dermis of the skin, where the collagen fibers are arranged in a network, and the dense regular tissues of tendons, where the collagen fibers are aligned to resist tearing.  Elastic connective tissue is made up of freely branching elastic fibers with fibroblasts in the space between the fibers.

 Cartilage o Unique connective tissue because is avascular (has no blood vessels). o Chondrocytes are cartilaginous cells, they secrete a gel like matrix that eventually surrounds and imprisons them, segregating them from direct contact with one another or any nutrient supply.  Cartilage heals slowly because nutrients must diffuse through the matrix to the chondrocytes; nutrients cannot reach the cell directly via bloodstream.  Each chondrocyte resides in a small ‘ lake’ within the matrix called the lacuna.  Osteoarthritis a disease in the joint is hard to treat because cartilage is avascular and does not respond to medication quickly.

 Hyaline cartilage is the most common type of cartilage.  Contains many collagen fibers and looks crystal blue in living tissue. Covers ends of bones, allowing them to slide against one another without damage. Also, found in your nose and trachea (main trunk of the respiratory tree).  During development, most of the skeleton is modeled in hyaline cartilage, then it is ossified and turned into bone.  Elastic cartilage is the 2nd type of cartilage.  Contains many elastic fibers in the matrix, allows the ear to bend and return to original shape.  The Epiglottis (large leap shaped piece of cartilage that lies over the top of the larynx) prevents food and liquid from entering the respiratory tract also contains elastic cartilage. o When you swallow the epiglottis bends to cover the opening of the trachea, afterwards it snaps back to its original position, allowing air to flow thought the windpipe.  Fibrocartilage is the 3rd type of cartilage.  The matrix is packed with collagen fibers, so it is found where extra strength is needed. It cushions your knee bones and disks between the vertebrae.  Bone is like steel - reinforced concrete. o Hard, mineralized tissue found in the skeleton, which is defining characteristics of vertebrates. o Bone cells secrete and osteoid (stage of bone matrix before it calcifies) substances that eventually hardens and surrounds the cells in an ossified matrix.  This osteoid ground substance contains protein, water, calcium, and phosphorous salts.  Once the matrix ossifies, the osteocytes (cells) remain in contact with one another through small channels called canaliculi.

 Blood and Lymph communicates with the entire body. o Blood and lymph are considered fluid connective tissues because their matrix is not solid.

 Blood is composed of specialized cells that are carried in the fluid matrix, or plasma (clear, yellowish fluid portion of blood).  Main function of blood is to transport nutrients, gases, hormones, and wastes. o Lymph is another fluid connective tissue, derived from interstitial fluid (fluid that fills the space between cells of tissues).  Includes cells as well as proteins and other compounds in its fluid matrix.  Fat and its job. o Adipose tissue contains fat cells, that are specialized for lipid storage.  Its matrix is a soft network of fibers holding the cells together and binding them to surrounding tissues.  Cellulite ‘bumps’ on the skin indicates where the adipose matrix is connected to the skin.  The adipose cells within the fibrous matrix can expand within the swelling of fat droplets they contain, whereas the matrix fibers cannot stretch as far.  The different stretching capacities of these two components of adipose tissue form dimples on the skin.  Muscle tissue. o Function of muscle tissue is to contract, as it contracts, the cells get shorter, and it generates force and often movement. o The three types of muscle tissue are skeletal, smooth, and cardiac.  Skeletal – Voluntary muscles… are striated.  Highly organized, cells laying parallel to each other, like a cable. When stimulated, they contract in unison.  Moves your limbs and stabilizes your trunks, including your bicep brachii and rectus abdominus.  The tissue is composed of long, multinucleate cells with visible striations. The cells of skeletal muscles extend the length of the muscle and are arranged in parallel groups called fascicles.  Smooth – non-voluntary… non-striated.  Lines the hollow organs such as blood vessels and digestive tracts.  Short, cylindrical cells that taper at both ends and have only one nucleus.

Cardiac –  Has short branched striated cells, with one nucleus at the center.  Specialized communication junctions called intercalated discs facilitates the heartbeat by transmitting the signal to contract. o Intercalated discs are gap junctions where the closely-knit cell membranes help spread the contraction impulses while also binding together.  Nervous Tissue o “irritable” meaning it responds to change in the environment. o Contains two categories of cells- neurons and neuroglia.  Neuroglia- supporting cells of nervous tissue. They do not send or receive electric impulses. They improve nutrient flow to neurons, provide physical support, remove debris, and provide electrical insulation.  Nerves- are clusters of neurons and their projections, sheathed in connective tissue.  Part of the peripheral nervous system  Sensory nerves conduct sensory messages from the body’s sensory organs to the spinal cord, which routes the info to the brain.  Motor nerves carry impulse that cause muscular movement or glandular secretion form the spinal cord to the muscles and glands.  The brain and spinal cord contains neurons that receive the integrate info and stimulate motor neurons to fire.  Part of the central nervous system. 

Organization of an organism. Atom  Molecule  Organelle  Cell  Tissue  Organ  Organ System  Organism

 11 Organ Systems in the human body o Integumentary (protecting and covering) o Skeletal (supporting) o Muscular (mobilizing and providing heat) o Nervous (sensing and responding) o Cardiovascular (transporting fluids and oxygen) o Respiratory (regulate gas exchange) o Urinary (maintain fluid balance) o Endocrine (regulate sequential growth and development) o Digestive (obtain nutrient) o Lymphatic (providing immunity) o Reproductive (continuing the species)

 Body Cavities o We have two body cavities. One is the dorsal cavity; contains brain and spinal cord. The ventral cavity; contains most of our internal organs. o Dorsal Cavity  Cranial Cavity – formed by cranial bones and contain brain.  Vertebral Cavity – formed by vertebral column and contains spinal cord and the beginning of spinal nerves. o Ventral Cavity  Thoracic Cavity – chest cavity; contains pleural and pericardial cavities and mediastinum.  Pleural Cavity – each surrounds a lung; the serous membrane of the plural cavities is called the pleura.  Pericardial Cavity – surrounds the heart, the serous membrane of the pericardial cavity is called pericardium.  Mediastinum – central portion of thoracic cavity between the lungs, extends from sternum to vertebral column and from neck to diaphragm; contains heart, thymus, esophagus, trachea, and several large blood vessels.  Abdominopelvic Cavity – subdivided into abdominal and pelvic cavities.

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 Abdominal Cavity – contains stomach, spleen, liver, gallbladder, small intestine, and most of large intestine; the serous membrane of the abdominal cavity is called peritoneum.  Pelvic Cavity – contains urinary bladder, portions of large intestine, and internal organs of reproduction Proximal / distal – opposite terms meaning near the core of the body vs farther from the core. Superior / inferior – opposite terms meaning above and below. Lateral / medial – opposite term meaning found near the side and found near the middle. Mediastinum – broad area between the lungs. Meninges – three protective membranes that cover the brain and spinal cord....