Term 1 Exam: Chapter 3 (Tissues) Objectives Flashcards
What is a tissue?
group of similar cells that usually have a common embryological origin and function together to carry out specialized activites
Define Histology
the science that deals with the study of tissues
What is a Pathologist?
A physician who examines cells and tissues for any changes that might indicate disease
What are the four major families of tissue that make up the human body?
- Epithelial Tissue 2. Connective Tissue 3. Muscular Tissue 4. Nervous Tissue
Where could you find epithelial tissue?
- covers body surfaces; - lines hollow organs, body cavities and ducts; - forms glands
What is the function of Connective tissue?
-Protects and supports the body and its organs; -Binds organs together, -Stores energy reserves as fat -provides immunity (lymph)
What is the function of Muscular tissue?
Generates physical force for movement, thereby creating body heat
What is the function of Nervous Tissue?
Detects changes in a variety of conditions and responds by initiating and transmitting nerve impulses that help control and coordinate body activities
What is a cell junction?
point of contact between neighbouring plasma membranes
There are five major types of cell junction, what are they?
- Tight junction 2. Adherens junction 3. Gap junction 4. Desmosome 5. Hemidesmosome
What is the function of a tight junction? Examples of where it would be found?
- forms a tight seal between cells (such as the epithelial cells that comprise the inner lining of the stomach, intestines and urinary bladder) -Prevent passage of substances between cells
What is the function of an adherens junction? Examples of where it would be found?
-Strongly fasten cells to each other -Found in epithelial surfaces = help resist separation during contractile activity ie lining of intestine
What is the function of a desmosome? Examples of where it would be found?
-Strongly fasten cells to each other; - prevent epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction -Found in outer layer of skin (epidermis) and heart
What is the function of a hemidesmosome? Examples of where it would be found?
Strongly anchor cells to an underlying basement membrane -Found in all epithelial layers
What is the function of a gap junction? Examples of where it would be found?
-Formed by minute, fluid-filled tunnels that permit passage of electrical signals or chemicals (ie ions or small molecules) from one cell to another -Located in some parts of the nervous system, heart muscle, and in the gastrointestinal tract
Compare epithelial and connective tissue. Include 4 points.
- Epithelial tissue contains many, tight-knit cells and little extracellular matrix while connective tissue has an abundance of extracellular matrix btwn widely scattered cells 2. Epithelial tissue is avascular, while connective tissue has numerous blood vessels 3. Epithelial tissue ALWAYS forms surface layers 4. Epithelial tissue is always located adjacent to connective tissue
What relationship between epithelial tissue and connective tissue is important for the survival and function of epithelial tissue?
Because epithelial tissue is avascular, it depends on the blood vessels in connective tissue for oxygen and nutrients and waste disposal (diffusion)
What are 8 General Features of Epithelium (epithelial tissue)?
- covering and lining epithelial cells arranged in continuous sheets in either single or multiple layers 2. Usually closely packed cells with little extracellular matrix between 3. Cells have three surfaces: a) lateral surface b) apical (free) surface c) basal surface (connected to basement membrane) 4. Numerous cell junctions that securely attach neighbouring cells 5. Avascular tissue exchanges materials with adjacent connective tissue via diffusion 6. Innervated (has nerve supply) 7. high capacity for cell division (to replace dead or damaged cells ie skin) 8. Has numerous functions including: a) protection b) filtration c) secretion d) absorption e) excretion
What are the two major types of epithelial tissue?
- Surface Epithelium 2. Glandular Epithelium
What is the structure of surface epithelium?
cells are arranged into one or more layers to form outer coverings and inner linings of the organs, cavities, and ducts of the body
The arrangement of cell layers reflects the function of surface epithelium. What are the three arrangements?
- Simple (unilaminar) epithelium = single layer of cells 2. Stratified (multilaminar) epithelium= two or more layers 3. Pseudostratified epithelium = single layer that appears stratified
Surface epithelial cells may be one of four shapes. What are these shapes?
- Squamous: cells are flattened 2. Cuboidal: Cells are cube-shaped or hexagonal 3. Columnar: cells are tall and cylindrical 4. Transitional: Cells are able to undergo changes in shape caused by distension
The combination of cell shape and arrangement of cell layers leads to 8 Classifications of Epithelial tissue, what are they?
- Simple squamous epithelium 2. Simple cuboidal epithelium 3. Simple Columnar Epithelium 4. Pseudostratified Columnar Epithelium 5. Stratified Squamous Epithelium 6. Stratified Cuboidal Epithelium 7. Stratified columnar epithelium 8. Transitional epithelium (urothelium)
Where would you find Simple squamous epithelium? What is the main function?
Single layer of flat cells: -Located in areas subject to little wear and tear -Adapted for diffusion (alveoli of lung) and filtration (blood filtration in kidneys)
Where would you find Simple cuboidal epithelium? What is it adapted for?
-Adapted for secretion and absorption -lines kidney tubules and smaller ducts of many glands
Where would you find simple columnar epithelium? What are some adaptations in these locations?
- found in upper respiratory passageways (has cilia in this location to move materials past cells) - Found in small intestine (has microvilli to increase efficiency of absorption)
What is the function of Pseudostratified columnar epithelium and an example of where it would be found?
-Functions in secretion or movement of materials by ciliary action -Found in upper respiratory passageways
What is the function of Stratified squamous epithelium and an example of where it would be found?
-Provides protection in areas subject to wear and tear -Found in outer layer of skin and lining of mouth
What is the function of stratified cuboidal epithelium and an example of where it would be found?
Rare type -Functions in protection -Found in ducts of sweat glands
What is the function stratified columnar epithelium and an example of where it would be found?
Rare Type -Functions in protection and secretion -Found in large ducts of some glands
What is an important feature of transitional epithelium? Provide an example of where it would be found.
Contains cells that may undergo changes in shape and therefore are located in areas subject to stretching -Example: urinary bladder
What is Glandular Epithelium?
Specialized epithelial cells organized to form glands that secrete substances into ducts, onto a surface or into the blood
What are the two categories of glandular epithelium?
Endocrine Glands Exocrine Glands
What are endocrine glands? Provide an example.
-Ductless -Secrete HORMONES which diffuse through interstitial fluid into the blood Eg: Thyroid gland, adrenal glands
What are exocrine glands? Provide an example.
Secrete substances into ducts -Structurally classified into unicellular and multicellular example: sweat glands, salivary glands
How are Exocrine Glands Classified? Label the chart
What is an example of a merocrine or eccrine gland?
Salivary Gland
What is an example of an apocrine gland?
Mammary glands
What is an example of a holocrine gland?
Sebaceous gland
What are 6 functions of connective tissue?
- Binds together, supports and strengthens other tissues
- portects and insulates internal organs
- compartmentalizes certain structures (eg skeletal muscles)
- blood is a connective tissue that transports substances
- Adipose (fat) tissue stores energy reserves
- Connective tissue is the main source of immune response (lymphatic)
What are four general features of connective tissue?
- composed of cells separated by an extracellular matrix that consists of ground substance and fibers
- Not usually located on free surfaces
- has a rich blood supply (except cartilage and tendons)
- Has a nerve supply (except in cartilage)
What are three characteristics of connective tissue?
- derived from mesenchyme
- immature cells have names that end with -blast (eg osteoblast)
- mature cells have names that end in -cyte (eg osteocyte)
What are 6 notable examples of connective tissue cells?
- fibroblasts
- macrophages
- plasma cells
- mast cells
- adipocytes
- leukocytes
What is important to note about immature connective tissue cells?
They retain the capacity for cell division and secrete the matrix
What is important to note about mature connective tissue cells?
reduced capacity for cell division and matrix secretion;
-major role is maintenance of the matrix
What does connective tissue extracellular matrix consist of?
- ground substance
- protein fibers
What is ground substance?
may be fluid, semifluid, gelatinous, or calcified and is composed of numerous polysaccharides (glycosaminoglycans) and proteins (proteoglycans)
What are three types of protein fibres found in the extracellular matrix of connective tissue?
- collagen fibres - provide strength and flexibility to the tissue
- elastic fibres - provide strength and elasticity
- reticular fibres - provide support and strength
What are two types of Embryonic Connective Tissue?
- Mesenchyme
- Mucous Connective Tissue
What is Mesenchyme?
Type of embryonic Connective tissue
-Gives rise to almost all other types of connective tissue
What is Mucous Connective Tissue?
A type of embryonic Connective tissue.
-Found primarily in the umbilical cord of the fetus
What are the three main types of Mature Connective tissue and their subcategories?
What is connective tissue proper?
Flexible and contains a viscous ground substance with abundant fibres
What is Loose Connective Tissue?
Sub category of CT Proper:
- Has loosely arranged fibers in the matrix
What is areolar connective tissue?
Include:
- Cell examples
- Types of fibres
- Type of ground substance
- example Location
- function
Type of Loose Connective tissue (subcategory of CT Proper)
- Has several types of cells: ie fibrolasts, macrophages etc
- Has All THREE types of fibers
- Ground substance is semifluid
- Located in subcutaneous layer of skin, blood vessels, etc
- Provides strength, elasticity, and support
What is Adipose tissue?
Include:
- Type of cell
- example Location
- function (hint there are two types of adipose)
Type of Loose CT (subcat of CT Proper)
- contains adipocytes that store triglycerides
- located in subq layer, around organs, etc
- WHITE Adipose: insulates, stores energy reserves, supports and protects various organs
- BROWN Adipose: generates heat in the newborn and is an excellent source of stem cells
What is Reticular connective tissue?
Include:
- Type of cell
- Types of fibres
- function
- Contains reticular fibers and reticular cells
- binds together cells of smooth muscle tissue, forms stroma of organs etc
What is Dense Connective Tissue? Types?
- Type of Connective Tissue Proper
- has densely arranged fibres in the matrix
- Dense regular connective tissue
- Dense irregular connective tissue
- Elastic Connective Tissue
What is Dense regular connective tissue?
Include:
- Type(s) of cells
- Type(s) of fibres
- example of where it could be found
- function
Type of Dense CT (sub cat of CT Proper)
- Contains rows of fibroblasts between numerous parallel bundles of collagen fibers
- forms tendons and most ligaments
- provides strong attachment between various structures
What is Dense irregular connective tissue?
Include:
- Type(s) of cells
- Type(s) of fibres
- example of where it could be found
- function
Type of Dense CT (sub cat of CT Proper)
- contains fibroblasts scattered among randomly oriented (irregularly arranged) collagen fibres
- located in dermis, periosteum, heart valves etc
- provides strength
What is Elastic Connective Tissue?
Include:
- Type(s) of cells
- Type(s) of fibres
- example of where it could be found
- function
Type of Dense Connective Tissue (subcat of CT Proper)
- Contains fibroblasts scattered among elastic fibers
- located in walls of elastic arteries, lung tissue etc
- provides elasticity and strength
What is Supporting Connective Tissue?
Type of Mature Connective Tissue:
- includes cartilage and bone that protects and supports soft tissues of the body
What is Cartilage tissue? What are the three types?
Type of Supporting CT
- Contains chondrocytes embedded in the lacunae of a gelatinous matrix that includes collagen fibers and elastic fibres
- avascular (heals slowly)
- Lacks nerves
- Usually covered by a perichondrium
- Hyaline Cartilage
- Fibrocartilage
- Elastic Cartilage
What is Hyaline Cartilage tissue?
Include:
- Type(s) of fibres
- example of where it could be found
- function
Type of Cartilage (sub cat of Supporting CT)
- has fine collagen fibres that are not visible with ordinary staining techniques
- located on ends of long bones, nose, trachea etc
- is most abundant (but weakest) type of cartilage
- provides flexibility and support; at joints it reduces friction and absorbs shock
What is Fibrocartilage tissue?
Include:
- Type(s) of fibres
- example of where it could be found
- function
Type of Cartilage Tissue (Subcat of Supporting CT)
- Contains visible bundles of collagen fibres, making it the strongest type of cartilage
- lacks perichondrium
- located in intervertebral discs, knee menisci etc
- provides strength and rigidity as well as flexibilty and support
What is Elastic Cartilage tissue?
Include:
- Type(s) of fibres
- example of where it could be found
- function
Type of cartilage tissue (subcat of Supporting CT)
- contains network of elastic fibers
- located in epiglottis, external ear etc
- maintains shape and provides strength and elasticity
What is bone tissue? What are the two following sub categories?
Subcategory of Supporting CT
- aka osseous
- contains osteocytes embedded in lacunae (with canaliculi) of a rigid, calcified matrix that includes collagen fibres
- Compact bone
- Spongy Bone
What is Compact Bone?
Include:
- composition
Type of Bone tissue (subcat of Supporting CT)
- composed of osteons (Haversian systems) in which there are concentric rings of matrix called lamellae
- each osteon containes a central (haversian) canal
What is spongy bone?
Type of Bone tissue (Subcat of Supporting CT)
- consists of tabeculae
- spaces between trabeculae contain red bone marrow
- bone supports, protects, helps generate movement, stores minerals and houses red marrow and yellow marrow
What is Liquid Connective Tissue? What are two subcategores?
Type of Mature Connective Tissue.
- includes
- blood
- lymph
What is Blood?
Include:
- Type(s) of cells
- Type of Matrix
- functions of cells
Type of Liquid Connective Tissue
- consists of a liquid matrix called plasma in which formed elements are suspended
- Formed elements include:
- erythrocytes (red blood cells): transport CO2 and O2
- leukocytes (white blood cells): phagocytosis, immunity, and allergic reactions
- thrombocytes (platelets) - blood-clotting
What is Lymph?
Type of Liquid Connective tissue
- interstitial fluid that flows in lymphatic vessels
What are epithelial membranes? What the principal epithelial membranes (3)?
consists of an epithelial layer and an underlying connective tissue layer
- Mucous Membrane (mucosa)
- Serous Membrane (serosa)
- Cutaneous Membrane (skin)
What is the mucous membrane?
Include:
- Example location
- Function(s)
- Name of Connective tissue layer
- lines a cavity that opens to the exterior (e.g. gastrointestinal tract, repiratory tract etc)
- Forms a barrier against entry of microbes
- Secretes mucus to prevent dehydration and trap pathogens
- Has a connective tissue layer called lamina propria
What is the Serous membrane?
Include:
- layers of the serous membrane
- Function(s)
- 3 Examples Serous Membrane and where they are located
has a
- Parietal layer: lines a body cavity that doesn’t open to exterior
- Visceral layer: covers organs inside the aforementioned cavities (lungs/stomach)
- epithelial layer secretes a lubricating serous fluid that reduces friction between the organs and the walls of the cavities
- Examples:
- Peritoneum
- Pericardium
- Pleura
What are the Synovial Membranes?
Include function(s), location and important terms.
Type of membrane that lack an epithelial layer
- Lines joint cavities, bursae and tendon sheaths
- Synoviocyes secrete components of a lubricating synovial fluid that reduces friction during movements
What is Muscular Tissue?
What are the three major types?
Tissue that consists of cells, usually called muscle fibres (myocytes) that are specialized to contract and therefore provide motion, maintain posture, provide protection and generate heat
- Skeletal muscle tissue
- Smooth Muscle Tissue
- Cardiac Muscle Tissue
What is Skeletal muscle tissue?
Attached to bones and consists of long, cylidrical cells that are striated and multinucleate
-Under Voluntary control
What is Cardiac Muscle Tissue?
Forms most of the wall of the heart and consists of striated, branching cells connected by intercalated discs
- under involuntary control
- single nucleate
What is Smooth muscle tissue?
Located primarily in the walls of hollow internal organs (ie stomach, blood vessels etc)
- Consists of non-striated spindle shaped cells
- Usually under involuntary control
What two major types of cells does Nervous Tissue consist of?
- Neurons
- Neuroglia
What are Neurons?
What are the different parts of a neuron?
-Cells of nervous tissue
- Detect stimuli
- convert stimuli into Nerve Action Potentials (Nerve impulses)
- conduct these messages to other neurons, muscle fibres or glands
- Consists of:
- Cell body - contains nucleus
- branched processes called dendrites (recieve stimuli)
- Axon - conducts nerve impulses away from cell body
What is Neurglia?
Nervous tissue cell
- Provide protection and support to the neurons
