Chapter 4 Flashcards
What is tissue
Group of cells that have a common origin in an embryo and function together to carry out specialized atoms
Histology is the science of the study of ______
Tissues
What are the 4 types of tissues
Epithelial, connective, muscular and nervous
Describe the function of epithelial tissue
Covers body surfaces, lines hollow organs, body cavities, ducts and forms glands
Allows body to interact w/ both environments
Describe the function of connective tissue
Protect and support body organs
Binds organs together, stores energy reserve as fats, help provide immunity to disease causing organisms
Describe the function of muscular tissue
Composed of specialized cells for contraction and generates force, generates heat for body
Describe the function of nervous tissue
Detects change in conditions and respond by generating electrical signals (nerve action potentials) that activate contraction and secretions
What are cell junctions ?
Contact points between the plasma membrane of tissue cells
What are the 5 types of cell junctions
Tight junctions
Adherents junctions
Desmosomes
Hemidesmosomes
Gap junctions
What is the structure and function of tight junctions
Structure: weblike strands of transmembrane proteins fused together with outer surface and the plasma membrane, seals off passageways between cells
Function: prevent passage of substances and contents of organs from leaking into the blood and other tissues
What is the structure and function of adherens junctions
Structure: plaque with dense layer of protein inside plasma membrane, attaches to membrane proteins and microfilaments of the cytoskeleton. Transmembrane glycoproteins (called adherins) join cells and insert into the plaque on the opposite side of the plasma membrane and attach aerially cross between cells
Function: help epithelial cell surfaces resist separation during contractile activities
What is the structure and function of desmosomes
Structure: plaques and transmembrane glycoproteins extend into the intracellular space and attach to intermediate filaments (keratin proteins) that extend from one side of the cell across the cytosol to the other side of the cell.
Function: prevent epidermal cells from separating under tension (eg. cardiac muscles during contraction), help cells and tissue stability
What is the structure and function of hemidesmosomes
Structure: transmembrane glycoproteins (integrins) on the inside side of the plasma membrane attach to intermediate filaments (keratin), and attach to laminin on the outside which are present in the basement membrane
Function: anchor cells to the basement membrane
What is the structure and function of gap junctions
Structure: membrane proteins (connexins) form tiny fluid tunnels (connexons) that connect neighbouring cells. The plasma membrane is not fused together, it is separated by an intracellular gap. Ions and small molecules can diffuse from the cytoplasm of one cell to another
Function: transfer nutrients and wastes, allow cells to communicate, enable nerve and muscle impulses to spread rapidly
What are the 3 difference between epithelial tissues and connective tissues
1) number of cells (epithelial are many cells packed together with little or no extracellular matrix , connective have a large extracellular matrix separating cells)
2) blood vessels (epithelial is a vascular, connective had a significant network of vessels)
3) surface (epithelial forms layers and are not covered by other tissues)
What are the 2 types of epithelial tissues
Surface and glandular
What are some general features of epithelial tissue
- covers the lining of surfaces
- form secretion portions of glands
- has to own nerve supply, but is avascular relying on connective tissue blood vessels to bring in nutrients and remove wastes by diffusion
- form boundaries between organs and the body from the external environment meaning it is subjected to physical stress and injury (has high rate of cell division to form/repair itself and replace old/dead cells )
What are the surface structures of epithelium
1- apical (faces the body surface, body cavity, the lumen of an organ, or tubular duct which receives secretions)
2- lateral (faces adjacent cells on either side in tight junctions, adheren junctions, desmosomes or gap junctions)
3- basal (the deepest layer, adhere to extracellular materials like the basement membrane, in hemidesmosomes)
Describe the epithelial tissue structure
Cells arranged into continuous sheets (in single or multiple layers) that are closely packed together by many cell junctions with little intercellular space between adjacent plasma membrane.
Consists of a basal membrane and a reticular lamina as a part of the thin extracellular basement membrane
Describe the basal membrane layer of the basement membrane
The layer that is deeper and secretes epithelial cells. Contains proteins (laminin, collagen, glycoproteins and proteoglycans). The laminin molecules adhere to integrins in hemidesmosomes and attach epithelial cells to the basement membrane
Describe the reticular lamina layer of the basement membrane
Closer to the underlying connective tissues and contains proteins such as collagen produced by connective tissue cells called fibroblasts
What is the function of epithelial tissues
Protect, secrete (mucous, hormones, and enzymes), absorbs (nutrients) and excretes (wastes)
What is the function of the basement membrane of epithelial tissues
Attach and anchor the connective tissue
Form a surface along for epithelial cells to migrate during growth or wound healing
Restrict passage of larger molecules
What’s the difference between endocrine glands and exocrine glands
Endocrine glands: secretions are hormones that enter interstitial fluid and diffuse into the blood
Exocrine glands: secrete into ducts that end up onto a surface that covers/lines epithelium
What are the chances main types of surface epithelium and the difference between them
Simple (single layer and made for exchange of substances ) and stratified (multilayered used for protection )
Surface Simple epithelium functions
A single(for simple) layer used for diffusion, osmosis, filtration, secretion and absorption
What are the 4 types of surface simple epithelium
1) simple squamous (endothelium lines the heart, and vessels of blood and lymph, mesothelioma forms a layer of serous membranes)
2) simple cuboidal
3) simple columnar (non-ciliated and ciliated)
4) pseudostratified columnar (non-ciliated and ciliated)
What is the function of surface stratified epithelium
Has 2 or more layers, that protect underlying tissues where there is significant wear and tear
What are the 4 types of surface stratified epithelium
1) stratified squamous (non-keratinized and keratinized)
2) stratified cuboidal
3) stratified columnar
4) transitional/urothelium (lines the urinary tract)
What are the 2 types of glandular epithelium and what is the main difference between them
Simple (unbranched) and compound (branched)
What are the 5 types of glands of simple glandular epithelium
1) simple tubular (glands of large intestine- secretory part is STRAIGHT, and attached to a single unbranched duct)
2) simple branched tubular (gastric bands- secretory part is BRANCHED and attached to a single unbranched duct)
3) simple coiled tubular (sweat glands- secretory part is COILED and attached to a single unbranched duct)
4) simple acinar (penile urethra gland- secretory portion is ROUNDED and attached to a single unbranched duct)
5) simple branched acinar (sebaceous gland- secretory part is ROUNDED AND BRANCHED and attached to a single unbranched duct)
What are the 3 types of glands of compound glandular epithelium
1) compound tubular (bulbourethral gland- secretory part is TUBULAR and attached to a branched duct)
2) compound acinar (mammary gland- secretory part is ROUNDED and attached to a branched duct)
3) compound tubuloacinar (acinar pancreatic gland- secretory part is TUBULAR AND ROUND and attached to a branched duct)
Exocrine glands classification is differentiated by how secretions are _______, whether the secretion is a ________ of a cell, and consists of an entire glandular cell.
Released
Product
How does the secretory process begin ?
With the ER and Golgi complex working together to form intracellular secretory vesicles that contain the secretory product
What are the 3 types of secretory glands and the secretions that are released for each. How are the secretions released in each
1) Merocrine - secretions are synthesized on rough ER’s ribosomes, and they are processed, sorted, and packaged by the Golgi complex and released from secretory vesicles by exocytosis (salivary and pancreas)
2) apocrine - accumulate secretions at the apical surface of the secreting cell, then pinched off the cell by exocytosis releasing the secretion and the cell repairs and repeats the process (sweat and mammary)
3) Holocrine- accumulate secretion in the cytosol, the cell matures and ruptured releasing the product, the cell then sloughs off and gets replaced (sebaceous)
What are some features of connective tissues
- limited cells and a large amount of extracellular matrix
- contains a ground substance, fibres and some cells
- functions by binding together, supporting and strengthening other body tissues, protects and insulates internal organs, compartmentalizes structures, and serves as a major transport system by blood as connective tissues is very vascular
What is the structure of the extracellular matrix in connective tissue
- consists of protein fibres and ground substance
- very vascular and supplied with nerves
- immature cells (eg. fibroblasts, chondroblasts, osteoblasts) retain capacity for cell division and secrete the extra cellular contents.
-once the extracellular matrix begins to be produced; immature cells begin to differentiate into mature cells (fibrocyte, chondrocyte, osteocyte) and reduce capacity for cell division that is involved in monitoring and maintaining the extra cellular matrix
What is the structure and function of the ground substance of connective tissue
Structure: between cells and fibres (may be fluid, semi fluid, gelatinous or calcified) containing water and an assortment of organic molecules (complex combination of polysaccharides and proteins)
Function: support cells, bind them, store water, a medium for exchange in substances between the blood and cells. Plays a role in tissue development, migrate, proliferate and change shape and how they carry out metabolic functions
Explain by hyaluronic acid as a ground substance
- viscous and slipper substance that binds cells, lubricators joints, maintain shape (eyeball)
- WBC, spent cells and bacteria produce the enzyme hyalurondase, which breaks down hyaluronic acid making it more liquify
(WBC’s that produce this enzyme help WBC’s move through the connective tissue to reach infection sites & sperm cells that do this allow the sperm to penetrate the oocyte)
What are the main proteins found in ground substance and their function
Adhesion proteins
- link components of the ground substance to one another, and to the surface of the cell
- main adhesion protein is fibrobectin that bind collagen fibres and ground substance together and attach cells to the ground substance
What are the 3 types of fibres in the extracellular matrix or connective tissues and their differences in structure and functions
1) collagen (contains protein collagen that is strong, resistant to pulling and stretching, allows flexibility) occurs in bundles which add strength. — Found in bones, cartilage, tendons, ligaments
2) elastic (contains protein elastin, which is surrounded by a glycoprotein called fibrilin, this fibre branched and joints together forming a fibrous network) provides strength and stability, but also able to stretch and return to its original shape. — found in skin, blood vessels walls and lung tissues
3) reticular (contain the protein collagen and a coating of glycoproteins, produced by fibroblasts) fine bundles, provides strength and support and forms a supportive network around cells in some tissues called stroma for soft organs — spleen and lymph nodes, also in blood vessel walls, forms the basement membrane of tissues
What are the 6 connective tissue cells
- fibroblasts
- macrophages
- plasmocytes
- mastocytes
- adipocytes
- Leukocytes
What is the structure and function of fibroblasts
Structure: large flat cells with branching processes present in general connective tissues
Function: develop monocytes (Type of WBC)
What are the two types of macrophages
Fixed (found in alveolar of lungs, or splenic tissues, residing in particular tissue) and wandering (has ability to travel through tissue and gather at sites of infections/inflammation to carry out phagocytosis)
What is the location of plasmocytes
- found in many places of the body but reside in connective tissues GI and respiratory tracts
What is the function of mastocytes
- involved in body reaction to inflammation, injury or infection
- hinds to and ingests to kill bacteria
Structure and function of adipocytes
- found deep to the skin and around organs of the heart and kidneys
- they are fat cells that store triglycerides
Function of leukocytes
Migrates from the blood into connective tissues with certain responses to certain conditions
- eg neutrophils at infection sites, eosinophils migrate to parasitic invasion sites and responses to allergies
The 5 types of connective tissues and their classifications
-loose (areolar, adipose, reticular)
- dense (regular, irregular and elastic)
- supportive (cartilage — hyaline, fibrocartilage, elastic cartilage)
- bone (compact, spongy)
- liquid (blood and lymph)
Describe the differences between the two embryonic connective tissues
1) mesenchyme (found under skin and along embryo developing bones)
— irregular shaped cells, embedded in a SEMIFLUID ground substance with RETICULAR fibres
— forms all other types of connective tissues
2) mucoid (found in the umbilical cord)
— scattered fibroblasts that are embedded in a VISCOUS jellylike ground substance containing COLLAGEN fibres
— main function is support
Explain the structure, location and function of areolar loos connective tissue
Structure: consists of all fibre types arranged randomly and cells embedded in a semifluid ground substance
Location: in and around body structures (packing material), deep subcutaneous layer, superficial papillary dermis, lamina propria of mucus, and around blood vessels nerves and body organs
Function: strength, stability, support
Structure, location and function of adipose connective tissue
Structure: derived from fibroblasts (adipocytes) specialized for storage of triglycerides (fats), large, centrally located droplet cells that fill up with a single large triglycerides and the cytoplasm and nucleus push the droplet into the periphery of the cell, increasing the tissue weight and makes more blood vessels form
Location: subcutaneous layer deep to the skin, around the heart and kidneys, yellow bone marrow, padding around joints and behind the eyeball
Function: decreases heat loss, an energy reserve, supports and protects organs.
What is the function of brown adipose tissues
Has a rich blood supply causing a darker color, found more in newborns, generating heat for maintenance of body temperature, the source of stem cells (repair, and replaces damaged tissues)
Structure, location and function of reticular connective tissues
Structure: fine, interlacing network of reticular fibres (collagen) and reticular cells
Location: supportive network stroma of the liver, spleen, lymph nodes, red bone marrow, reticular lamina of basement membranes around blood vessels and muscles
Function: forms the stroma of organs, binds smooth muscle tissue cells, filter and remove worn out blood cells in the spleen, and microbes in lymph nodes
Structure, location and function of dense regular connective tissues
Structure: shiny white extracellular matrix of collagen fibres arranged in bundles with fibroblasts in rows between them
Location: forms tendons, most ligaments, and aponeuroses
Function: provide strong attachments between structures and withstands tension and pulling along the axis of fibres
Structure, location and function of dense irregular connective tissue
Structure: made of collagen fibres irregularly arranged with a few fibroblasts
Location: in sheets of fasciae, deep region of dermis, fibrous pericardium, the periosteum of bone, the perichondrium of cartilage, joint capsules, membrane capsules, and around organs (kidney, liver, testes, lymph nodes, and heart valves)
Function: provides tensile strength
Structure, location and function of elastic dense connective tissue
Structure: elastic fibres with fibroblasts between them
Location: lung tissues, artery walls, trachea, bronchial tubes, vocal cords, suspensory ligaments of penis, and between some vertebral ligaments
Function: all stretching of organs, strong, and can recoil to original shape, important for breathing of lungs and beating of heart
Structure and function of cartilage
Structure: a dense network of collagen fibres firmly embedded in chondroitin sulfate, has a gel like ground substance. Has few cells and a large extracellular network like connective tissues, but no nerves or blood vessels. It secretes antiangiogenesis factor that goes against blood vessel growth.
Function: supports body tissues and forms the network in newborns
What are the two cells of mature cartilage and their structures
Chondrocytes (in groups or single spaces of the matrix - lacunae)
Perichondrium (has a dense irregular connective tissue that covers and surrounds the surface of most cartilage and contains blood vessels and nerves) - source of new cartilage cells
Two types of cartilage growth
Interstitial and appositional
What is the differences of interstitial growth and appositional growth
Interstitial:
— occurs within the tissues
— rapid increase in size because of division of existing CHONDROCYTES,
— the continuous deposition of high amounts of extracellular matrix by the chondrocytes (which synthesize new matrix and push away from eachother causing cartilage to expand from within)
Appositional:
— occurs at the outer surface
— cells of the inner cellular layer of perichondrium differentiate into CHONDROBLASTS and surround with extracellular matrix to become Chondrocytes
— the matrix then accumulated beneath the perichondrium, growing in width
The structure, location and function of hyaline cartilage
Structure: resilient GEL GROUND SUBSTANCE, with prominent chondrocytes in lacunae surrounded by the PERICHONDRIUM
Location: and the ends of long bones, anterior ends of the ribs, nose, parts of larynx, trachea, bronchi, and bronchial tubes, embryonic and fetal skeleton
Function: provides a smooth surface for movement at joints, and flexibility and support (weakest type)
Structure, location and function of fibrocartilage
Structure: has chondrocytes among THICK BUNDLES of COLLAGEN FIBRES within the extracellular matrix NO PERICHONDRIUM
Location: pubis symphysis, intervertebral discs, menisci, portion of tendons that insert into cartilage
Function: support and join structures together, strengthen and rigidity (very strong)
Structure, location and function of elastic cartilage
Structure: chondrocytes in THREADLIKE NETWORK of ELASTIC FIBRES within the extracellular matrix with a PRESENT PERICHONDRIUM
Location: epiglottis, auricle, and Eustachian tubes
Function: provides strength and elasticity, maintains shape of certain structures
General features of bone tissues
- contains cartilage, joints and bones
- support soft tissues, protect delicate structures, and works with muscles to generate movement
- stores calcium and phosphorous
- house red bone marrow that produces blood cells, and contains yellow bone marrow that stores triglycerides
- bones and organs are composed of connective tissues
Structure, location and function of compact bone tissue
Structure: consist of OSTEONS (havarien system), containing LAMELLAE (rings of extra cellular matrix with MINERAL SALTS - calcium and phosphates) that provide the “hardness and strength”. Also contains COLLAGEN FIBRES, and LACUNAE (spaces between lamellae that have osteocytes- mature bone cells), a CANALCULI (network of processes of osteocytes that provide routes for nutrients to the reach the osteocytes and wastes to exit) and a CENTRAL CANAL (contain blood vessels and nerves)
Location: shafts of long bones, and a part of many bones of the body
Function: support, protection, storage, house blood forming tissues, enable movement with muscles
Structure, location and function of spongy bone tissues
Structure: has NO OSTEONS, consist of Solomon’s of bone (TRABECULAE), contain LAMELLAE, OSTEOCYTES, LACUNAE, and CANALCULI. Has spaces between the trabecular filled with red bone marrow
Location: ends of long bones and on many other types of bones of the body
Function: support, protect, storage, house blood forming tissue, serve as lever and act with muscle tissues to enable movement
Structure, location and function of blood
Structure; blood plasma (pale yellow fluid with water, nutrients, wastes, enzymes, proteins, hormones, gases, and ions) and forms elements (erythrocytes RBC, leukocytes WBC, thrombocytes PLATLETS)
Location: within blood vessels
Function: RBC transport O2&CO2, WBC carry on phagocytosis and mediate allergic reactions, and immune system responses, platelets are essential for blood clotting
Extracellular fluid that flows in _____ vessels, consisting of several types of cells in a clear liquid extracellular matrix
Lymph
What is a membrane
Flat sheet of tissue that covers/lines a part of the body
What are the two types of membranes
Epithelial and synovial
What are the 3 types of epithelial membranes
mucous, serous and cutaneous
Differences between mucous, serous and cutaneous membrane structures
- MUCOUS line cavities that open directly to the exterior, SEROUS lines cavities that do not open directly to the exterior, and CUTANEOUS covers body surfaces like deep and superficial skin
- MUCOUS contains a lining layer of epithelium (goblet cells secrete mucous and slippery fluids to prevent drying) and underlying connective tissue layer that is areolar (lamina propria) that supports the epithelium and has tight junctions connective cells so materials don’t leaked through, and goblet cells
- SEROUS consist of areolar connective tissue covered by mesothelium. The mesothelium secretes serous fluid, a watery lubricant that allows organs to glide. Has 2 layers- parietal (attached and likes cavity walls) and visceral (sticks to organs within the cavity)
- CUTANEOUS, has 2 layers; an epidermis (keratinized stratified squamous epithelium) and dermis (dense irregular connective tissue and areolar tissue)
Difference in mucous, serous, and cutaneous membrane functions
MUCOUS- body defence mechanisms (barrier to microbes, and other pathogens so they have a difficult time penetrating), trap particles in respiratory tract, and lubricate foods of GI tract, allows flexibility of the membrane, provide protection, hold vessels in place, provide a vascular source for epithelium, O2 and nutrients diffuse from the lamina propria to the epithelium, and CO2 from the epithelium to the lamina propria
SEROUS- allows organs to glide
CUTANEOUS- protect underlying tissues
Synovial membrane structure, location and functions
Structures: lines cavities of free moving joints, contains connective tissue, but no epithelial membranes due to lack of epithelium. Composed of discontinuous layer of cells (synoviocytes) which are close to the synovial cavity (space between bones), and a layer of connective tissue (areolar and adipose) deep to the synoviocytes.
Location: free moving jojnts
Function: the synoviocytes secrete synovial fluid to lubricator and nourish the cartilage covering the bones at movable joints and contain macrophages that remove microbes and debris from the joint cavity
Features of muscle tissue
- consist of elongated cells (muscle fibres and myocytes) that use ATP to generate force
- produce body movement, maintain posture, generate heat and provide protection
What are the 3 types of muscle tissues
Skeletal, cardiac and smooth
Structure, location and function and mode of control of skeletal muscle tissue
Structure: long, cylindrical, striated fibres that vary in length, multinucleated
Location: attached to bones by tendons
Function: motion, posture, heat production, and protection
Mode of control: contract/relax by conscious control
Structure, location, function and mode of control of cardiac muscle tissues
Structure: branched, striated fibres, and an single central nucleus. Attached end to end by intercalated discs (transverse thickenings of the plasma membrane) contain desmosomes (strengthens the tissues and holds the fibres together for contraction) and gap junctions (provide routes for quick conduction during electrical signals)
Location: heart wall
Function: pump blood to all parts of the body
Mode of control: involuntary, not a conscious control
Structure, location, function, and mode of control of smooth muscles
Structure: nonstriated fibres, small spindle shaped cell that is thick in the middle, contain a single nucleus. Has gap junctions (connect individual fibres)
Location: eye iris, walls of hollow organs (blood vessels, airways of lungs, stomach, intestine, gall bladder, uterus)
Function: motion (constrict blood vessels and airways, propel food through GI tract, contract bladder or uterus)
Mode of control: usually involuntary in area with no gap junctions (eyes) can produce contraction on smooth muscle fibres individually
General features of nervous tissue
- consist of neurons and neuroglia
- neurons are nerve cells which are sensitive to stimuli, convert stimuli into electrical signals (nerve action potentials) and conduct to other neurons, muscle tissues or glands
Structure of a neuron
Cell body: nucleus to other organelles
Dendrites: taper, branched, short cell extensions, the site of receiving input
Axon: single, thin, cylindrical, long, the input portion, conducts nerve impulse towards another neuron or tissues
What is electrical excitability
The neurons and muscle fibres are “excitable cells” as the exhibit electrical excitability meaning they respond to certain stimuli by producing electrical signals (action potential)
Action potentials travel along the _______ _____ of a neuron/muscle fibre to the presence of a specific __________ ion channel
Plasma membrane
Voltage gated
What’s the difference for an action potential when it forms in a neuron of a muscle fibre
Neuron: the neuron releases chemicals called neurotransmitters allowing neurons to communicate with one another or to muscle fibres or glands
Muscle fibre: the muscle fibre contracts, resulting in movement, food propulsion, etc.
