Flashcards in Tissue Level (235 #4, 230 #3) Deck (53):
epithelial tissues /epithelium
cover body surfaces and line hollow organs, body cavities and ducts - they also form glands. Allows body to interact with internal and external environment. Cells arranged in sheets in single or multiple layers, held together by many cell junctions. May be covering epithelia, lining epithelia or glandular epithelia. Many cells are tightly packed together and are avascular.
protect and support the body and it's organs. bind organs together, store energy reserves as fat, help provide body with immunity to disease-causing organisms. Consists of relatively few cells and abundant ECM of ground substance and protein fibres. Highly vascular except for cartilage, tendons, ligaments.
cells specialized for contraction and generation of force, also generates heat that warms the body.
detects changes in a variety of conditions inside andoutside the body and responds by generating electrical signals that activate muscular contractions and glandular secretions.
3 functions of epithelial tissues
1) selective barriers that limit or aid the tx of substances in/out of the body.
2) secretory surfaces that release products produced by the cells onto free surfaces.
3) protective surfaces that resist the abrasive influences of the environment.
apical (free) surface
faces the body surface, cavity, lumen or tubular duct - may contain cilia or microvilli.
opposite the apical surface - basal surface of basal layer of epithelial cells anchor to the basement membrane with hemidesmosomes.
layers of epithelial tissue
1) simple (one layer)
2) pseudostratified (appears to be several layers, but is one)
3) stratified (many layers)
shapes of epithelial tissue
1) squamous (flat)
2) cuboidal (square)
3) columnar (rectangular)
4) transitional (variable)
simple squamous epithelium
single layer of flat cells - filtration or diffusion is priority.
Endothelium lines heart and blood vessels.
Mesothelium forms serous membranes that line the thoracic and abdominopelvic cavities and covers the organs within them,
simple cuboidal epithelium
single layer of cube-shaped cells that function in secretion and absorption. Covers the ovaries, kidneys and in eyes and lining some glandular ducts.
nonciliated simple columnar epithelium
a single layer of nonciliated (microvilli'd instead) rectangular cells that lines most of the GI tract and contains cells for absorption/mucous secretion.
ciliated simple columnar epithelium
single layer of ciliated rectangular cells found in a few portions of the upper resp tract where it moes foreign particles trapped in mucous out of resp tract.
ciliated pseudostratified columnar epithelium
contains goblet cells and lines most of the upper resp tract, moves mucous in the resp tract.
nonciliated pseudostratified columnar epithelium
no goblet cells for mucous secretion, instead functions in absorption and protection in the ducts of many glands, the epididymis and part of the male urethra
stratified squamous epithelium
apical layer cells and cells of layers many deep to it are flat - keratinized variety forms the epidermis, non-keratinized variety forms the lining of the mouth
stratified cuboidal epithelium
found in adult sweat glands and in a portion of the male urethra
stratified columnar epithelium
found in a portion of the male urethra and large excretory ducts of some glands, functions in protection and secretion
several layers of cells whose appearance varies on the degree of stretching - urinary bladder.
gland shape classification
single cell or group of epithelial cells adapted for secretion.
1) unicellular (goblet cells) or multicellular (sudoriferous/sweat, sebaceous and salivary)
2) simple (non-branching) or compound (branching)
3) tubular, acinar (rounded secretory portion), or tubuloacinar
exocrine gland classification
1)merocrine - secretions are synthesized on ribosomes attached to rough ER, goes through Golgi and released via exocytosis (salivary)
2) apocrine - accumulate secretions at the apical surface and cell portion pinches off via exocytosis (mammary)
3) holocrine - secretion in cytosol and as cell matures it ruptures & contains lipids from plasma membrane (sebaceous)
Types of Connective Tissue Cells
Mesenchymal cells give rise to cxtive tissue cells. Immature cells = 'blasts', mature cells = 'cytes'.
1) fibroblasts - large flat cells with branches, most numerous cells, present in all types, secrete ECM
2) macrophages - perform phagocytosis
3) plasma cells - secrete antibodies, found esp in GI and resp tracts, but around glands, lymph nodes, spleen and red blood marrow
4) mast cells- secrete histamine, can bind to and ingest bacteria, abundant alongside blood vessels
5) adipocytes - fat storage cells, deep to skin and around organs
6) white blood cells, migrate from blood in response to infection
with fibers make up ECM. Supports and binds cells, stores water, exchanges materials - contains H2O, polysaccharides like hyaluronic acid, chondroitin sulfate (cartilage, for resilience), dermatan sulfate and keratin sulfate (glycosaminoglycans - GAGs). Also contains adhesion proteins - fibronectin.
Embryonic Connective Tissues
1) mesenchyme - forms almost all other connective tissue. Found in embryos and sometimes along adult blood vessels.
2) Mucous - widely scattered fibroblasts in viscous ECM with fine collagen. Found in umbilical cord - supports.
Mature Connective Tissues
5) Liquid (blood, lymph)
Loose Connective Tissue - Areolar
most widely distributed, fibres are arranged randomly with several kinds of cells in semifluid ground sub. Called 'packing material' of body, found around nearly every structure, subQ layer deep to skin - strength, elasticity, support. Lamina propria of mucous membranes.
Loose Connective Tissue - Adipose
adipocytes (derived from fibroblasts) that are triglyceride storages (a large central droplet, with cytoplasm and nucleus pushed off to side). Most is WHITE adipose tissue which is highly vascular, meaning new tissue grows new blood vessels so a fat person has higher BP. BROWN (BAT) is widespread in fetus and infant. Found wherever Aerolar is found, yellow bone marrow, pads around joints and behind eyeball. Reduces heat loss, serves as energy reserve, supports and protects organs.
Loose Connective Tissue - Reticular
fine interlacing network of reticular fibres and cells. Stroma (supporting framework) of liver, spleen, lymph nodes, red bone marrow. around blood vessels and muscles, reticular lamina of basement membrane.
Dense Connective Tissue - Regular
shiny white ECM, mainly regularly arranged collagen fibres with fibroblasts in rows between. Collagen fibres are not living, so damaged tendons/ligaments heal slowly. Forms tendons, ligaments and aponeuroses - tissue withstands pulling along long axis of fibres.
Dense Connective Tissue - Irregular
collagen fibres, irregularly arranged with fibroblasts. Occurs in sheets (fasciae - tissue beneath skin and around muscles/organs), deeper region of dermis, fibrous pericardium, periosteum (bone), joint capsules, membrane capsules around organs and heart valves. Provides tensile strength in many directions.
Dense Connective Tissue - Elastic
predominantly elastic fibres with fibroblasts between fibres. Found in lung tissue, elastic artery walls, trachea, bronchial tubes, vocal cords, susp ligament of penis - Allows stretching of various organs, is strong and can recoil.
Cartilage - Hyaline
ground sub is resiliant gel with fine collagen fibres. Prominent chondrocytesfound in lacunae surrounded by perichondrium - most abundant cartilage in body, ends of long bones, ant ends of ribs, nose, parts of larynx/trachea/bronchi & tubes, embryonic & fetal skeleton. Provides smooth surface for movement in joints. Weakest type of cartilage.
Cartilage - Fibrocartilage
chondrocytes scattered among clearly visible bundles of collagen - no perichondrium. Found in Pubic Symphisis, invertebral discs, menisci. Strongest type of cartilage - strength and rigidity.
surrounds the surface of most cartilage - a covering of dense irregular conective tissue containing blood vessels and nerves, and is the source of new cartilage cells.
there is growth from within the tissue - chondrocytes divide and form new ECM, the cartilage expands like bread rising. Childhood and adolescent growth
growth at the outer surface of the tissue. cells in the inner cellular layer of the perichondrium differentiate into chondroblasts, forms new ECM, etc. Starts later than interstitial and continues through adolescence.
Cartilage - Elastic
chondrocytes in threadlike network of elastic fibres in ECM, perichondrium present. Epiglottis, auricle, eustachian tubes. Provides strength and elasticity, maintains shape.
Bone/Osseus Tissue - Compact
ECM of mineral salts and collagen. Osteocytes are located in lacunae. OSTEON (haversian systems) contains:
1) lamellae - concentric rings of ECM
2) Lacunae - small spaces between lamellae for osteocytes
3) Canaliculi - networkds of little canals that are routes for nutrients to reach osteocytes and allow wastes to leave them
4) Central (haversian) canal - contains blood vessel and nerves.
Bone/Osseus Tissue - Spongy
lacks osteons. consists of columns of bone called trabeculae containing the 4 parets, where between is filled with red blood marrow.
Liquid Connective Tissue - Blood
liquid ECM called blood plasma - pale yellow with nutrients, wastes, enzymes, plasma, proteins. Also contains RED BLOOD CELLS (erythrocytes - tx O2, removes CO2), WHITE blood cells (leukocytes - phagocytosis) and platelets (thrombocytes - blood clotting).
Liquid Connective Tissue - Lymph
extracellular fluid that flows in lymphatic vessels. Similar to blood plasma, but less protein.
flat sheets of pliable tissue that cover or line a part of the body. The majority of membranes consist of an epithelial layer and an underlying connective tissue layer and are called epithelial membranes. The principal epithelial membranes of the body are mucous membranes, serous membranes, and the cutaneous membrane, or skin. Another type of membrane, a synovial membrane, lines joints and contains connective tissue but no epithelium.
mucous membrane or mucosa
lines a body cavity that opens directly to the exterior - entire digestive, respiratory, and reproductive tracts, and much of the urinary tract. lining layer of epithelium and an underlying layer of areolar connective tissue called the lamina propria (supports the epithelium, binds it to the underlying structures, flexibility, protection for underlying structures, holds blood vessels in place
serous membrane/ serosa
lines a body cavity that does not open directly to the exterior (thoracic or abdominal cavities), and it covers the organs that are within the cavity. areolar connective tissue covered by mesothelium (simple squamous epithelium) layer attached to and lining the cavity wall is called the parietal layer, adheres to the organs within the cavity is the visceral layer. secretes serous fluid, a watery lubricant. e.g. pleura, pericardium, peritoneum.
cutaneous membrane or skin
covers the entire surface of the body and consists of a superficial portion called the epidermis (keratinized simple squamous epithelium) and a deeper portion called the dermis (dense irregular connective tissue and areolar connective tissue)
line structures that do not open to the exterior, but lack an epithelium. discontinuous layer of cells called synoviocytes and a layer of connective tissue (areolar and adipose) deep to the synoviocytes. Synovial fluid lubricates and nourishes and contains macrophages that remove microbes and debris.
SKELETAL MUSCLE TISSUE
Long, cylindrical, striated fibers that vary greatly in length,roughly cylindrical, multinucleated cell with nuclei at periphery. voluntary
CARDIAC MUSCLE TISSUE
Branched, striated fibers, only one centrally located nucleus (occasionally two). Attach end to end by transverse thickenings of plasma membrane called intercalated discs , which contain desmosomes (strengthen) and gap junctions (Route for quick conduction of electrical signals). Involuntary (not conscious) control.
SMOOTH MUSCLE TISSUE
involuntary, nonstriated , small spindle‐shaped cell thickest in middle, tapering at each end, and containing a single, centrally located nucleus. Gap junctions connect MOST fibres (not in iris of eye) so they contract in unison.
Neurons (nerve cells), which consist of cell body and processes extending from cell body (one to multiple dendrites and a single axon); and (2) neuroglia, which do not generate or conduct nerve impulses but have other important supporting functions. Dendrites are tapering, highly branched, and usually short cell processes (extensions) -receiving or input portion of a neuron. The axon of a neuron is a single, thin, cylindrical process that may be very long - output portion.
diseases in which antibodies produced by the immune system fail to distinguish what is foreign from what is self and attack the body's own tissues - the most prevalent disorders of connective tissues.
A decrease in the size of cells, with a subsequent decrease in the size of the affected tissue or organ.