Tissues

Describe the attachment of epithelia to the basal lamina

Epithelia lack blood vessels (avascular) so they need to stay firmly attached to the underlying connective tissue for nourishment

Differentiate merocrine glands from apocrine glands.

Merocrine glands: cells secrete their substances by exocytosis for example, sweat glands and the salivary glands Apocrine glands: A portion of the plasma membrane buds off the cell, containing the secretion e.i goblet cells

Describe and differentiate the different types of cartilage

The three types of cartilage are hyaline cartilage, elastic cartilage and fibrocartilage. Hyaline cartilage is the most abundant type of cartilage and can be found lining bones in joints and inside the bones. Elastic cartilage is found in the pinna of the ear and several tubes, like the auditory canals and the larynx. Fibrocartilage is found in areas requiring tough support or great tensile strength, like intervertebral discs and sites where ligaments and tendons connect to bones.

Define Tissue

Tissues are collections of cells and cell products that perform specific, limited functions

Transitional Epithelium

Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage Appearance changes as stretching occurs Situated in regions of the urinary system (e.g. urinary bladder)

describe the different types of fasciae found in the body

superficial fascia: found in virtually all regions of the body. It is mainly loose areolar connective tissue and adipose deep (or muscle) fascia: Dense fibrous CT, surrounds the muscles, bones, nerves and blood vessels of the body visceral (or parietal) suspends the organs within their cavities and wraps them in layers of connective tissue

Describe how connective tissue establishes the framework of the body

Support- Bones cartilage Protection- Blood and lymphatic Bind together other body tissues;

Briefly describe the 3 types of muscle tissue and how they are controlled

The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control. Skeletal muscle fibers occur in muscles which are attached to the skeleton. They are striated in appearance and are under voluntary control

Define and describe the membranes (visceral/parietal) of the body

The cutaneous membrane is skin. Skin consists of a layer of stratified squamous epithelium (epidermis) firmly attached to a thick layer of dense connective tissue (dermis). It differs from other membranes because it is exposed to air and is dry. The serous membranes (or serosae) consist of simple squamous epithelium (a mesothelium) supported by a layer of connective tissue (areolar). These moist membranes line the closed, internal divisions of the ventral body cavity. The three types of serous membranes are: 1) the pleura, lining the pleural cavities and covering the lungs; 2) the peritoneum, lining the peritoneal cavity and covering the abdominal organs; and 3) the pericardium, lining the pericardial cavity and covering the heart. The mucous membranes (or mucosae) consist of epithelial tissue (usually stratified squamous or simple columnar epithelia) on a layer of loose connective tissue called the lamina propria (from the Latin, meaning "one's own layer"). The mucosae line the body cavities that open to the exterior, such as the digestive, respiratory, reproductive, and urinary tracts. These membranes are kept moist by bodily secretions. Synovial membranes are composed of connective tissue. They surround the cavity of joints, filling the space with the synovial fluid that they make. The synovial fluid lubricates the ends of the bones allowing them to move freely

Briefly define what ground substance is

The intercellular material in which the cells and fibers of connective tissue are embedded

Identify the 4 main tissues of the body and briefly describe their role

Epithelial tissue: -Covers exposed surfaces -Lines internal passage ways -Forms glands Connective tissue: -Fills internal spaces -Supports other tissues -Transports materials -Stores energy Muscle tissue: -Specialized for contraction -Skeletal muscle -Heart muscle contracts and relaxes to help move blood along -Walls of hollow organs to help move things along Neural tissue: -Transmits impulses and forms nerves -Carries electrical signals from one part of the body to another

4 functions of epithelial tissues

Functions of epithelial tissues: -Provide physical protection -Control permeability -Provide sensation -Produce specialized secretions

Briefly define and describe the following: tight junction, gap junction and desmosome.

Gap junctions—allow rapid communication Held together by channel proteins (junctional proteins, connexons) Allow ions to pass Coordinate contractions in heart muscle Occluding (Tight) junctions—between two plasma membranes Adhesion belt attaches to terminal web Prevents passage of water and solutes Isolates wastes in the lumen Desmosome At a desmosome the opposing plasma membranes are locked together The desmosomes are very strong and resist stretching and twisting

Identify the function and location of a goblet cell

Goblet cells are glandular simple columnar epithelial cells, they are found inside the trachea, bronchus, bronchioles, small intestines and colon. Their function is to secrete mucin, which dissolves in water to form mucus

Briefly describe 3 factors that help maintain the integrity of the epithelia

Intercellular connections Attachment to basal lamina Epithelial maintenance and repair

Briefly describe the modes of secretion under the following headings: merocrine, apocrine and holocrine.

Merocrine secretion Is produced in Golgi apparatus Is released by vesicles (exocytosis) For example, sweat glands Apocrine secretion Is produced in Golgi apparatus Is released by shedding cytoplasm For example, mammary gland Holocrine secretion Is released by cells bursting, killing gland cells Gland cells replaced by stem cells For example, sebaceous gland

Describe the basic structure and role of neural tissue

Nervous tissue is made up of different types of nerve cells, all of which have an axon, the long stem like part of the cell that sends action potential signals to the next cell. Nervous tissue is specialized to react to stimuli and to conduct impulses to various organs in the body which bring about a response to the stimulus

Describe the relationship between form and function for each type of epithelium.

Simple squamous epithelium: -Absorption and secretion -Where a slick, slippery surface is needed to reduce friction eg: lining of the ventral body cavities, lining of the heart and blood vessels, inside the eye Stratified squamous epithelium: -Located where mechanical or chemical stresses are severe -Protects against attacks -Keratin protein adds strength and water resistance Simple cuboidal epithelium: Glands, ducts, portions of kidney tubules; thyroid gland -Secretion and absorption Stratified cuboidal epithelia: -Sweat ducts and mammary ducts Protection, secretion, absorption Transitional Epithelium: -Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage -Appearance changes as stretching occurs -Situated in regions of the urinary system (e.g. urinary bladder) Simple columnar epithelium: -Lining of stomach, intestine, gallbladder, uterine tubes and collecting ducts of kidneys -Protection, absorption and secretion Pseudostratified columnar epithelium: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract -Cilia movement -Protection, secretion Stratified columnar epithelium: -Protection -Small areas of the pharynx, epiglottis, anus, mammary gland, salivary glad ducts, and urethra Mesothelium (middle) -Lines body cavities -These have a special name because they do not communicate with the outside world Endothelium: -Lines heart and blood vessels Glandular Epithelia: -Endocrine glands Release hormones: (endocrine secretions) into interstitial fluid They then enter the bloodstream for distribution to the body no ducts (their secretions are not released into ducts Exocrine glands Produce exocrine secretions: -They go onto epithelial surfaces -Travel through ducts eg: perspiration on skin, tears in the eyes, milk produced by mammary glands

Identify the 3 main cell shapes of epithelial cells, where each is typically found and relate the location to the function of the cell type.

Squamous epithelia: thin and flat Cuboidal epithelia: square shaped Columnar epithelia: tall, slender rectangles Location: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys) Function: Protection, secretion, absorption

List and define the types of loose and dense connective tissue

Types of Dense CT 1. Dense regular connective tissue attaches muscle to bone and with the cells organized in one direction so that it pulls in one direction, like a tendon that connects to the bicep. It is made primarily of parallel collagen fibers, a few elastic fibers and the major cell type is the fibroblast. Ligament-tendon-Aponeurosis 2. Dense irregular connective tissue are like capsules for organs and joints that wrap around them. Irregular allows for movement in different directions, like the shoulder or under the skin or the fibrous capsule of an organ or joint. It's made primarily of irregularly arranged collagen fibers, some elastic and the major cell type is the fibroblast. gastrointestional tract- dermis 3. Elastic connective tissue has the ability to receive a relatively large amount of blood all at once with a lot of pressure. The aorta for example has to expand and recoil RIGHT AWAY because the next heart beat is on the way. It's just like a dense regular connective tissue but with a high proportion of elastic fibers instead Types of Loose CT 1. Areolar connective tissue is soft and gel like with some elasticity and holds interstitial fluid which carries and delivers nutrients or waste. It helps facilitate the passage of these molecules for the most part. This is also where so many of our defenses wait. Macrophages, mast cells and white blood cells gather here. It wraps and cushions organs and is widely distributed under epithelia of the body. This contains all 3 fiber types in its matrix secreted by fibroblasts. 2. Adipose (fat) tissue are required to protect your organs and help maintain your body temperature. For example, lots of this is found in woman's breasts and under our skin. 3. Reticular connective tissue forms the soft internal skeleton of something. The spleen and lymphoid organs for example, is full of these because it acts like a filter that catches all sorts of things. found around the liver, the kidney, the spleen, and lymph nodes, as well as in bone marrow

Briefly discuss the 3 types of fibers that occur in connective tissue

•Collagenous Fibers white protein fibers that constitute much of the intercellular substance and the connective tissue of the body. Collagenous fibers contain collagen. They are often arranged in bundles that strengthen the tissues in which they are imbedded. •Elastic Fibers Elastic fibers are made of elastin and are stretchable.Are bundles of proteins (elastin) found in extracellular matrix of connective tissue and produced by fibroblasts and smooth muscle cells in arteries. •Reticular Fibers Reticular fibers join connective tissues to other tissues