Chapter 4 - Tissue Level Flashcards
Define histology
Study of science that deals with tissues - a group of cells that usually has a common roofing in an embryo and function together to carry out specialized activities
What are the 4 types of body tissues?
Epithelial: covers body surfaces and lines hollow organs, cavities, and ducts
Connective: protects and supports the body and its organs
Muscular: specialized from contraction and generation of forces which generates heat that warms the body
Nervous: detects changes in a variety of conditions inside and outside the body and responds by generating APs that activate contractions and glandular secretions
What are cell junctions? Describe the 5 principal types
Cell junctions are contact points between membranes of tissue cells; 5 important types:
Tight: web-like strands of transmembrane proteins that fuse the outer surfaces of adjacent membranes to seal off passageways between them
Adherens: contain plaque (dense layer of proteins) that attaches to both membrane proteins and microfilaments of cytoskeleton; help resist separation during contraction
Desmosomes: Contain plaque and also have transmembrane glycoproteins that extend into the IC space to attach cells to one another; plaque attaches to cytoskeleton via intermediate filaments
Hemidesmones: Resemble desmosomes but do not link adjacent cells - they anchor cells to a basement membrane
Gap: connexion proteins (fluid-filled tunnels) connect neighbouring cells
Epithelial vs. connective tissues
Epithelial cells lack blood vessels and form surface layers that are always adjacent to blood rich connective tissue
Describe the general features of epithelial tissue, including the various surfaces & their functions
Epithelial tissue (epithelium) consists of cells arranged in continuous sheets that are closely packed and held together by cell junctions
The apical (free surface) faces the body surface, body cavity, the lumen (interior space) of an organ, or a tubular duct
The lateral surface face the adjacent cells on either side
Basal surfaces are opposite of apical - they face deep such as the basement membrane
What is the basement membrane?
A thin EC layer that attaches to and supports the overlying epithelial tissue and forms a surface where cells migrate during growth/healing; restricts passageway between E and C tissues; and filtrates blood
It consists of the basal lamina (closet to basal surface) and the reticular lamina
Covering & lining epithelium vs. Glandular epithelium
These are the 2 division of epithelial cells
Covering & lining: forms the outer covering of skin and internal organs
Glandular: forms the secreting portion of glands
Describe how epithelial tissues are classified (two characteristics)
- Arrangement of cells in layers:
Simple: single layer that rests on basement membrane
Pseudostratified: single layer that rests on basement membrane, however appears to be multiple layers as cells are not level
Stratified epithelium: 2+ layers of cells
- Cell shapes:
Squamous: thin
Cuboidal: cube-like
Columnar: column-like
Transitional cells: change shape from squamous to cuboidal and back
Describe the location and function of each type of epithelium:
Simple:
- Simple squamous
- Simple cuboidal
- Simple columnar (ciliated vs. non-ciliated)
- Pseudostratified columnar (ciliated vs. non-ciliated)
Stratified:
- Stratified squamous (keratinized vs. nonkeratinized)
- Stratified cuboidal
- Stratified columnar
- Transitional
Simple squamous: lines cardiovascular and lymphatic system and forms the serous membrane for filtration, diffusion and secretion
Simple cuboidal: ovary, eye, and kidney tubules for secretion and absorption
Simple columnar
- Noncilitated: found in GI tract for secretion and absorption
- Ciliated: found in reparatory, uterine tract, and ventricles and aids in movement
Pseudostratified columnar:
Ciliated: lines airways of respiratory tract and secretes mucous for trading particles
Nonciliated: lines large ducts of many glands and aids in absorption & protection
Stratified squamous
Keratinized: forms superficial alter of sin to protect against abrasion, water loss, UV, and foreign invasion
Nonkeratinized: lines wet surfaces for first line against microbes
Stratified cuboidal: lines ducts of sweat & esophageal glands for protection and limited secretion and absorption
Stratified columnar: lines urertra and large excretory glands for protection and secretion
Transitional: lines bladders and ureters/urethra and allows for stretching while holding fluids
Define gland - exocrine vs. endocrine
Gland: consist of cells that secrete substances into ducts, onto a surface, or into the blood. There are 2 types:
Endocrine: hormones enter interstitial fluid and diffuse directly into the blood stream without passing though a duct
Exocrine: secrete products into ducts that empty onto the surface of a covering & lining epithelium
Describe the structural classification of exocrine glands (unicellular, multicellular)
Unicellular: single celled glands
Multicellular (common): composed of many cells that form distinctive structured that are categories according to:
- Branched (compound) or unbranched (simple)
- Shape of secretory portion: tubular, acinary (rounded), and tubuloacinary (tubular and rounded parts)
Describe the functional classifications of exocrine glands (merocrine, apocrine, holocrine)
Merocrine: synthesized on ribosomes; processed, sorted, and packaged by the golgi complex and released exocytosis
Apocrine: accumulate secretary product at the apical surface and then pinches off by exocytosis to release its secretion
Holocrine: accumulate secretory product in cytosol and eventually ruptures and becomes the secretory product
What are the 2 basic elements of connective tissue?
Extracellular matrix: material between cells that consist of protein fibers and ground substance
Cells
Describe the following connective tissue cells:
- Fibroblasts
- Macrophages
- Mast cells
- Adipocytes
- Leukocytes
Fibroblasts: large flat cells that migrate through tissues secreting fibers and components of found substance
Macrophages: develop from monocytes and destroy bacteria and debris via phagocytosis
Mast cells: produce histamine which dilates small blood vessels during inflammation and kills bacteria
Adipocytes: stores fat
Leukocytes: WBC (neutrophils or eosphils)
What are the combines of ground substance and protein fibers (3) within the connective tissue ECM?
Ground substance: material that supports cells, binds them together, stores water, and provides a medium for exchange of substances
3 types of fibers:
1) Collagen: strong, flexible bundles of collagen protein
2) Elastin: stretchable but strong
3) Reticular: made of collagen/glycoproteins; provide support in blood vessel walls and form branching networks around cells
Describe the structure, location, and function of each type of embryonic connective tissue:
Mesenchyme
Mucous connective tissue
Mesenchyme: contains irregular mesenchymal cells embedded in semifluid substance that is located under the skin of developing bones and along some blood vessels (adults)
Mucous connective tissue: scattered fibroblast embedded in jelly-like substance that contains collagen and supports the fetus and is found is the umbilical cord
Describe the structure, location, and function of each type of mature loose connective tissue:
Areolar
Adipose
Reticular
Areolar: consists of fibers embedded in semifluid ground substance and found in the subQ layer in every body structure for strength, elasticity, support
Adipose : derived from fibroblasts (adipocytes) that are specialized for storage of triglycerides (fats) and can reduce heat loss, reserve energy, & support/protect organs
Reticular: fine interlacing network of reticular fibre and cells that forms storm of organs; binds smooth muscle tissue; filters worn blood vessels in spleen/lymph nodes
Describe the structure, location, and function of each type of mature dense connective tissue:
Dense regular
Dense irregular
Elastic
Dense regular: made up of bundles of collagen with fibroblasts that forms tendons & ligaments and provides astrong attachment between structures that can withstand tension
Dense irregular: made up of irregularly arranged collagen and few fibroblasts that provides pulling strength in many directions
Elastic: elastic fibers & fibroblasts located in lund, arteries, trachea, airways that allows stretching and recoiling
Define cartilage and discuss its resiliency
Cartilage - dense networking of collagen and elastic fibers firmly embedded in chondroitin sulphate (gel-like ground substance)
Resiliency refers to ability to assume original shape after deformation and is due to chondroitin sulfate
Cells of mature cartilage are called ________
chondrocytes (singly) or lacunae (in groups with spaces)
Describe the 3 types of cartilage
Hyaline (most abundant): contains a resilient gel as ground substance and provides smooth surfaces for movement at joints, flexibility, and support; weakest type of cartilage and can be fractured
Fibrocartilage: has chondrocytes among clearly visible thick bundles of collagen and supports and joins structures together, the strongest type of cartilage
Elastic: has chondrocyte in threadlike network of elastic fibers within EC matrix and provides strength and elasticity; maintains shape of certain structures
Interstitial vs. appositional repair and growth of cartilage
Interstitial: growth from within the tissue (childhood)
Appositional: growth at the outer surface (adolescence)
Describe the 4 parts of an osteon (haversian system)
Lamellae: centric rings of ECM that give bone its hardness and compressive strength
Lacunae: small spaces between lamellae that contain mature bone cells called osteocytes
Cancaliculi: project from lacunae are are networks of canals for osteocytes that provide nutrients and allow waste to leave
Central canal (haversian canal): contains blood cells and nerves
Define a spongy bone
It lacks osteons and consists of columns called trabeculae
Which of the following is not a connective tissue?
A) bone tissue B) blood tissue C) Cartilage D) elastic tissue E) All are examples of connective tissues
E) All are examples of connective tissues
What is blood tissue?
A liquid connective tissue that has an ECM called blood plasma and formed elements (WBC, RBC, platelets)
Describe the function of RBC, WBC, and platelets
RBC: transport oxygen and remove carbo dioxide
WBC: immunity
Platelets: blood clotting
Describe the following epithelial membranes:
Mucous
Serous
Cutaneous
Synovial
Mucous: line body cavities that open to the outside; the connective tissue layer is called the lamina proporia that supports the epithelium
Serous: line cavities that do not open directly to the outside; has two layers:
1) Parietal - attached to lines in the cavity wall and 2) visceral - covers and adheres to organs within cavity
Cutaneous: covers the surface of the body that consists of the epidermis and dermis
Synovial: lines joints
Describe the 3 types of muscular tissue:
Skeletal
Cardiac
Smooth
Skeletal: long, cyndrical striated fibres that are multinucleate that aid in motion, posture, heat production, & protection
Cardiac: branched striated fibers with one centrally located nucleus that are attached to an intercalated disc; functions to pump blood
Smooth: involuntary, non striated
Describe the structural features and functions of nervous tissue (neurons & microglia)
Consists of neurons & microglia:
Neurons covert stimuli into action potentials and function these to other neurons, muscle tissue, or glands
Neuroglia do not generate action potentials but have many supportive functions
What is systemic lupus erythmatosis (SLE)?
A chronic inflammatory disease of connective tissue occurring mostly in non-white women during childbearing age
Connective tissue disorders are most commonly autoimmune diseases
