Chapter 4 Flashcards
What is a tissue?
A group of cells that usually have a common origin in an embryo and function together to carry out specialized activities
What are the Four basic types of body tissues?
- Epithelial tissue
- Connective tissue
- Muscular tissue
- Nervous tissue
What are cell junctions and what type of junctions is there?
Contact points between the plasma membranes of tissue cells
- Tight junctions
- Adherents junctions
- Desmosomes
- Hemideamosomes
- Gap junctions
What is the function of tight junctions?
Fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells. Prevent contents of organs from leaking.
What are adherents junctions and their function?
Contain plaque, a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton. Cells join together with caherins
Adherents junctions help epithelial surfaces resist separation during various contractile activities like food moving through intestines
What are desmosomes and their function?
Contain plaque and have transmembrane glycoproteins(Cadherins) that extend into the intercellular space between adjacent cell membranes and attach cells to one another but unlike adherents junction the plaque of desmosomes does not attach to microfilaments
Contributes to stability of cells and tissue common among epidermis, cardiac muscle cells of heart
What are hemidesmosomes and their function?
Resemble desmosomes, but they do not link adjacent cells.
Transmembrane glycoproteins are interims, that attach to intermediate filaments made of keratin inside cell and attach to laminin outside of cell
What are gap junctions and their function?
At the gap junction connections form tiny fluid-filled tunnels called connexons
Gap junctions transfer nutrients and waste in a vascular tissue like the lens and cornea, allow cell tissue to communicate, in an embryo chemical and electrical signals can regulate growth, allow nerve impulses to travel rapidly
What are the differences between epithelial tissue and connective tissue?
- Epithelial tissue is tightly packed with little extra cellular matrix and connective tissue has a large amount of extra cellular matrix
- Epithelial tissue has no blood vessels and connective tissue has a significant network of blood vessels
- Epithelial tissue forms surface layers and is not covered by other tissue other than blood vessel lining where blood passes over
What is epithelial tissue and it’s function?
Consists of cells arranged in continuous sheets, in either single or multiple layers
Epithelial tissue protects,secretes (mucous, hormones, and enzymes), absorbs (nutrients in the gastrointestinal tract), and excretes (various substances in the urinary tract)
The various surfaces of covering and lining epithelial cells often differ in structure and have specialized functions
Is avascular and has its own nerve supply
What is the apical surface of an epithelial cell?
Apical surface faces the body surface, a body cavity, the lumen of an internal organ, or a tubular duct that receives cell secretions
May contain cilia or microvilli
What is the lateral surface of an epithelial cell?
Faces adjacent cells on either side
May contain tight, adherens, desmosomes, gap junctions
What is the basal surface of an epithelial cell?
Opposite the apical surface
They adhere to extra cellular materials such as basement membrane
What is the basement membrane?
A thin extracellular layer that commonly consists of two layers, basal lamina and reticular lamina
Basement membranes form a surface along which epithelial cells migrate during growth or wound healing, restrict passage of larger molecules between epithelium and connective tissue and participate in filtration of blood in the kidneys
What is basal lamina layer of the basement membrane?
Closer to and secreted by the epithelial cells. Laminin molecules in this layer adhere to integrity in hemidesmosomes and attach epithelial cells to the basement membrane
What is the reticular lamina layer of the basement membrane?
Closer to the underlying connective tissue and contains proteins such as collagen produced by connective tissue cells called fibroblasts
How does epithelial tissue exchange substances with connective tissue?
Diffusion
How do epithelial tissues contestant or repair and renew itself?
It has a high rate of cell division
What are the different roles epithelial tissue play in the body?
Protection Filtration Secretion Absorption Excretion
What are the two types of epithelial tissue?
- Covering and lining epithelium/ surface epithelium
2. glandular epithelium
How can you classify epithelial tissue?
- Arrangement of cells in layers
2. Cell shape
What are the different epithelium layers?
- Simple - single layer of cells functions in diffusion, osmosis, filtration, secretion and absorption
- Pseudostrtified - appears to have multiple layers because nuclei are at different levels but is actually simple
- Stratified - consists of two or more layers that protect underlying tissues found in locations with considerable wear and tear
What are the different cell shapes?
Squamous cells
Cuboidal cells
Columnar cells
Transitional cells
Squamous cells
Thin, allowing for rapid passage of substances through them
Cuboidal cell
Tall as they are wide, cube shaped. May have microvilli function for secretion or absorption
Columnar cells
Taller than they are wide, protect underlying tissue. Apical surface can have cilia or microvilli and specialize for secretion and absorption
Transitional cells
Change shape, squamous to cuboidal and back. For organs like the bladder that stretch then collapse.
Types of epithelial tissues: simple epithelium?
A. Simple squamous epithelium 1. Endothelium ( lines heart, blood vessels, lymphatic vessels) 2. Mesothelium (forms epithelial layer of serous membranes) B. Simple cuboidal epithelium C. Simple columnar epithelium 1. Nonciliated (lacks cilia) 2. Ciliated (contains cilia) D. Pseudostratified columnar epithelium 1. Nonciliated (lacks cilia) 2. Ciliated (contains cilia)
Types of epithelial tissue: stratified epithelium?
A. Stratified squamous epithelium 1. Nonkeratinized (lacks keratin) 2. Keratinized (contains keratin) B. Stratified cuboidal epithelium C. Stratified columnar epithelium D. Transitional epithelium or urothelium (lines most of urinary tract)
Location and function of simple squamous epithelium?
Lines cardiovascular and lymphatic system where it’s known as a endothelium
Forms the epithelial layer of serous membranes where it’s called mesothelium
Air sacs of lungs, capsule of kidneys, eardrum
Filtration, diffusion, secretion, not good for wear and tear
Simple cuboidal epithelium location and function?
Surface of ovary, anterior surface of lens of eye, pigmented surface of retina, kidney tubules and smaller ducts, secreting portion of thyroid and pancreas
Secretion and absorption
Nonciliated simple columnar epithelium?
Gastrointestinal tract, ducts of glands, gallbladder
Secretion and absorption
Ciliated columnar epithelium
Lines bronchioles, uterine tubes, uterus, paranasal sinuses, central canal of spinal chord, ventricles of brain
Cilia move in unison to expel mucous or particles towards throat or from ovaries
Nonciliated pseudostratified columnar epithelium
Lines epididymis large ducts of glands and male urethra
Absorption and secretion
Ciliated pseudostratified columnar epithelium location and function?
Lines airways of upper respiratory tract
Secrets mucous that traps foreign particles and cilia sweeps away mucous for elimination from the body
Stratified squamous epithelium location and function?
keratonized variety forms superficial layer of skin; non keratinized variety lines wet surfaces like mouth and esophagus and covers tongue
Protection against abrasions, water loss, ultraviolet radiation, foreign invasion, first line of defence from microbes
Stratified cuboidal epithelium location and function?
Ducts of adult sweat glands and esophageal glands part of male urethra
Protection; limited secretion and absorption
Stratified columnar epithelium location function?
Part of urethra, large excretory ducts of some glands like esophageal small areas in anal mucous membrane part of conjunctiva eye
Protection and secretion
Transitional epithelium location and function?
Lines urinary bladder and portions of ureters and urethra
Allows urinary organs to stretch and maintain protective lining while holding fluids and not rupturing
Glandular epithelium function?
Secretion
What is a gland?
Consists of epithelium that secrets substances into ducts, onto surface, or eventually into the blood if there is no ducts
What are the two types of glands?
Endocrine gland
Exocrine gland
What kinds of secretions come from endocrine glands?
Hormones
Because endocrine glands use the bloodstream they have far reaching effects
Where do exocrine glands secrete?
Use ducts to empty on surface of skin
Limited effects
What are the structural classifications of exocrine glands?
- Unicellular-single-celled glands
- Multicellular glands-makes up most exocrine glands, composed of many cells that form a distinctive microscopic structure or macroscopic organ.
How are multicellular glands categorized? And what are some examples?
- Wether their ducts are branched or unbranched
- Shape of the secretory portions of the gland
Sweat, oil, and salivary glands
What are the different types of multicellular exocrine glands and how do you differentiate them?
- simple gland-does not branch
- Compound gland-branches
- Tubular gland - tubular secretory parts
- Acinar glands - rounded secretory portions also alveolar glands
- Tubuloacinar glands - have both tubular and more rounded secretory parts
Structural classification scheme for multicellular exocrine glands: simple glands
A. Simple tubular B. Simple branches tubular C. Simple coiled tubular D. Simple acinar E. Simple branched acinar All simple glands attach to a single unbranched duct
Structural classification scheme for compound glands
A. Compound tubular
B. Compound acinar
C. Compound tubuloacinar
All counting glands attach to a branched duct
How do Merocrine glands secrete?
Most exocrine glands are merocrine glands
Secretions are released from the cell in secretory vesicles via exocytosis
How do apocrine glands secrete their product?
Portion of the cell pinches off by exocytosis from the rest of the cell to release the secreation
How do holocrine glands secrete their product?
Accumulate a secretory product in their cytosine as the secretory cell matures, it ruptures and becomes the secretory product.
Functions of connective tissue?
- Binds, supports, and strengthens other tissue
- Protects and insulates internal organs
- Compartmentalism’s structures such as skeletal muscles
- Major transport system within the body
- Primary location of stored energy
- Main source of immune responses
What are the two basic elements of connective tissue?
Extracellular matrix
Cells
What is a connective tissues extracellular matrix? And what are the major components?
Material located between its widely spaced cells
- Ground substance
- Fibers
What are the different types of connective tissue cells?
- Fibroblasts
- Macrophages
- Plasma cells
- Mast cells
- Adipocytes
- Leukocytes
What are fibroblasts?
Large, flat cells with branching processes. Present in all general connective tissue, usually most numerous.
What are macrophages?
A type of white blood cell
What are plasma cells?
Most plasma cells reside in connective tissue of the gastrointestinal and respiratory tract
What are mast cells?
Involved in the inflammatory response, the body’s reaction to injury or infection can also bind to, ingest, and kill bacteria
What are adipocytes?
Fat cells, connective tissue cells that store fat. Found deep to the skin and around organs like heart and kidneys
What are leukocytes?
White blood cells, in certain responses these migrate from blood into connective tissue
What is ground substance?
Component of a connective tissue between cells and fibers
Supports cells, binds them together, stores water, provides medium for exchange
What is hyaluronic acid?
Viscous, slippery substance that binds cells together, lubricates joints, and helps maintain the shape of the eyeballs.
What is chondroitin sulfate?
Provides support and adhesiveness in cartilage, bone, skin, and blood vessels.
What’s the main adhesion protein of connective tissue?
Fibronectin
What are the three fibers embedded in the extracellular matrix between the cells?
Collagen fibers
Elastic fibers
Reticular fibers
What is the function of fibers?
Strengthen and support connective tissue
What is collagen fiber?
Very strong and resist pulling or stretching,not stiff, allows tissue flexibility
What is elastic fibers?
Smaller than collagen, branch and join together to make a network within connective tissue. Strong but can stretch 150% of relaxed length
Reticular fibers?
Collagen arranged in fine bundles, provide support in the walls of blood vessels and form network around cells in some tissues
What is stroma?
Supporting framework (formed by the reticular connective tissue) of many soft organs like spleen and lymph nodes also help form basement membrane
Embryonic connective tissue
Found in embryo
Two types:
Mesenchyme
Mucous connective tissue
Mature connective tissues?
Connective tissue proper
Supporting connective tissue
Liquid connective tissue
Connective tissue proper
Flexible with viscous ground substance and abundant fibers 1. Loose connective tissue A. Areolar B. Adipose C. Reticular 2. Dense connective tissue A. Dense regular connective tissue B. Dense irregular connective tissue C. Elastic connective tissue
Supporting connective tissue
1. Cartilage A. Hyaline B. Fibrocartilage C. Elastic cartilage 2. Bone tissue A. Compact bone B. Spongy bone
Liquid connective tissue
- Blood
2. Lymph
Chondrocytes
Mature cartilage cells that occur single or in multiples in the lacunae
Perichondriun
Dense irregular connective tissue surrounding most cartilage and contains blood vessels and nerves and makes new cartilage cells
Three types of cartilage?
Hyaline cartilage
Elastic cartilage
Fibrocartilage
What are the two basic patterns of cartilage growth?
Interstitial growth - growth from within the tissue
Appositional growth - growth at out surface of tissue
How is bone tissue classified?
Compact or spongy
What’s the basic unit of compact bone?
Osteon
What are the four parts of the osteon?
- Lamellae - responsible for compact nature
- Lacunae - small spaces that contain osteocytes
- Canaliculi - projects from lacunae, providing routes for nutrients to reach osteocytes
- Central canal - contains blood vessels and nerves
Spongy bone
Lacks osteons and consists of column of bones called trabeculae
Red blood cells
Transport o2 and remove carbon dioxide
White blood cells
Involve in phagocytosis, immunity, and allergic reactions
Platlets
Participate in blood clotting
Lymph
Extracellular fluid that flows in lymphatic vessels
Membranes
Flat sheet of pliable tissue that cover or line a part of the body
Epithelial membrane
Epithelial layer and underlying connective tissue layer
Mucous membrane
Epithelial membrane that lines a body cavity that opens directly to the exterior such as
Digestive
Respiratory
Reproductive
Lamina propria
Connective tissue layer of a mucous membrane is Areolar connective tissue, supports epithelial tissue, binds it to underlying structures, allows flexibility
Serous membrane
Lines body cavity that doesn’t open to exterior directly. Two layers:
Parietal
Visceral
Cutaneous membrane
Skin that covers the entire surface
Superficial portion is epidermis
Deeper portion is dermis
Synovial membranes
Lines cavity’s of freely moving joints
Composed of layers of cells called synoviocytes
Muscular tissue
Elongated cells called muscle fibers or myocytes
Three types of muscular tissue?
Skeletal
Cardiac
Smooth
Skeletal muscle tissue location and function?
Usually attached to bones by tendons
Voluntary
Motion, posture, heat production, protection
Cardiac muscle tissue location and function?
Branched striated fibers, attach by intercalated discs, involuntary movement
Heart wall
Pumps blood to body
Smooth muscle tissue location and function?
Non striated fibers, contains single, centrally located nucleus, involuntary movement
Iris of eyes, walls of hollow internal structures such as blood vessels, airways to lungs, stomach, intestines, gallbladder, urinary bladder, uterus
Function: motion
Two principle cells of nervous tissue?
Neurone and neuralgia
Neurons
Convert stimuli into electrical signals called nerve action potentiak
Dendrites
Major receiving or input portion of a neuron
Axon
Output portion of a neuron, conducting nerve impulses toward another neuron or to some other tissue
Excitable cells
Neurons and muscle fibers because they exhibit electrical excitability
