Chapter 5 Flashcards
4 tissue types?
Epithelial, connective, nervous, muscular
What is an organ?
A structure with discreet boundaries that is composed of 2 or more tissue types
What is histology?
The study of tissues and how they are arranged into organs
What is a tissue?
A group of similar cells and cell products working together to perform a specific role in an organ
How do the 4 tissue types vary from one another?
Types and functions of their cells, characteristics of the matrix, and relative amount of space occupied by cells vs matrix
What is the cell matrix made up of?
Fibrous proteins and a clear gel known as ground substance OR tissue fluid, ECF, interstitial fluid, or tissue gel
What is a longitudinal section (l.s.)?
Tissue cut on its’ long axis
What is a cross section (c.s. or x.s.) or transverse section (t.s.)?
Tissue cut perpendicular to long axis of organ
What is an oblique section?
Tissue cut at an angle between cross and longitudinal sections
How do epithelial tissues look?
Sheets of closely adhering cells, one or more cells thick
Where are epithelial tissues found?
Body surfaces and lining body cavities
Is epithelial tissue vascular or avascular?
Avascular
Functions of epithelial tissue?
Protect deeper tissues from injury and infection, produce and release chemical secretions, excrete wastes, absorb chemicals and nutrients, selectively filter substances, sense stimuli
What is a basement membrane?
A layer between an epithelium and underlying connective tissue. Anchors the 2 together
How close are cells in epithelial tissue?
Very close
Mitosis rate of epithelial tissue?
High
What is the basal surface?
Surface of epithelial cell facing the basement membrane
What is the apical surface?
Surface of epithelial cell that faces away from basement membrane
Structure of simple epithelia?
1 layer of cells, named by shape, all cells touch basement membrane
Structure of stratified epithelia?
More than 1 layer, named by shape of apical cells, some cells rest on top and don’t touch basement membrane
What are the types of epithelia with only one layer of cells?
Simple squamous, simple cuboidal, simple columnar, psuedostratified columnar
How do pseudostratified columnar cells work?
Every cell reaches the basement membrane, but not all cells reach the free surface
What are goblet cells?
Wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia
Stop! Go look at a simple squamous epithelium slide
Done
What does simple squamous epithelium do?
Permits rapid diffusion or transport of substances, secretes serous fluid
Simple squamous epithelium locations?
Alveoli, glomeruli, endothelium, and serosa
Simple cuboidal epithelium functions?
Absorption and secretion, mucus production and movement
Simple cuboidal epithelium locations?
Liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules
Simple columnar epithelium functions?
Absorption and secretion, secretion of mucus
Simple columnar epithelium additional structures?
Oval nuclei in basal half of cell, brush border of microvilli, sometimes ciliated, may possess goblet cells
Simple columnar epithelium locations?
Lining of GI tract, uterus, kidney, and uterine tubes
Pseudostratified epithelium additional structure?
Nuclei at several layers, has cilia and goblet cells
Pseudostratified epithelium functions?
Secretes and propels mucus
Pseudostratified epithelium locations?
Respiratory tract, portions of male urethra
Types of stratified epithelia?
Stratified squamous (common), stratified cuboidal, stratified columnar (rare). And, transitional epithelium
Types of stratified squamous epithelia?
Keratinized and nonkeratinized
Difference between keratinized and nonkeratinized stratified squamous epithelia?
Keratinized - found on skin surface, abrasion resistant
Nonkeratinized - lacks surface layer of dead cells
Functions of keratinized stratified squamous epithelium?
Resists abrasion, retards water loss through skin, resists penetration by pathogenic organisms
Keratinized stratified squamous epithelium locations?
Epidermis. Palms and soles are heavily keratinized
Nonkeratinized stratified squamous epithelium functions?
Resists abrasion and penetration of pathogens
Nonkeratinized stratified squamous epithelium locations?
Tongue, oral mucosa, esophagus, and vagina
Transitional epithelium structure?
Multilayered epithelium w/ surface cells that change from round to flat when stretched
Transitional epithelium function?
Allows for filling of urinary tract
Transitional epithelium locations?
Ureter and urinary bladder
What is connective tissue?
A diverse, abundant type of tissue in which cells occupy less space than matrix. Most cells aren’t in direct contact w/ each other
What does connective tissue do?
Support, connect, and protect organs
Vascularity of connective tissue?
Highly variable. Loose connective tissues have a lot of blood vessels, cartilage has few or no blood vessels
Functions of connective tissue?
Connecting organs, support, physical protection, immune protection, movement, storage, heat production, and transport
What do fibroblasts do?
Produce fibers and ground substance of matrix
What do macrophages do?
Phagocytize foreign material and activate immune system when they sense foreign matter (antigens)
What are leukocytes?
White blood cells
Types of leukocytes?
Neutrophils and lymphocytes
What do neutrophils do?
Attack bacteria
What do lymphocytes do?
React against bacteria, toxins, and other foreign agents
What do plasma cells do?
Synthesize antibodies (proteins)
What do mast cells do?
Secrete heparin and histamine
What do adipocytes do?
Store triglycerides (fat molecules)
What are collagenous fibers?
Tough, flexible, and stretch-resistant protein fibers. Make up tendons, ligaments, and deep layer of skin
What are reticular fibers?
Thin collagen fibers coated with glycoprotein. Form framework of spleen and lymph nodes
What are elastic fibers?
Thinner than collagenous fibers, they branch and rejoin each other. Made of protein called elastin. Allows stretch and recoil
What is the matrix made up of?
Glycosaminoglycans (GAGs), proteoglycans, adhesive glycoproteins
Types of loose connective tissue?
Areolar and reticular
Types of dense connective tissue?
Dense regular connective and dense irregular connective
How does loose connective tissue generally look?
Gel-like ground substance between cells
How does dense connective tissue generally look?
Fibers filling spaces between cells
What is areolar tissue?
Loosely organized fibers, abundant blood vessels, a lot of seemingly empty space. Possess all 6 cell types, fibers in random directions. Found almost everywhere in body
How does areolar tissue look?
Like a bunch of strings with clumps in them. Loosely organized fibers, abundant blood vessels. Underlies epithelia, in serous membranes, between muscles
How does reticular tissue look?
Squiggly with dots. Mesh of reticular fibers and fibroblasts. Forms supportive stroma for lymphatic organs.
How does dense regular connective tissue look?
Densely packed, parallel collagen fibers. Squiggly. Nuclei in the middle. Compressed fibroblast nuclei. Make up tendons and ligaments
How does dense irregular connective tissue look?
A lot of like swirls all around each other. Densely packed, randomly arranged, collagen fibers and few visible cells. Withstands unpredictable stresses. Deepest layer of skin, capsules around organs
What are adipocytes?
Cells that store fat
What is adipose tissue (fat)?
Tissue in which adipocytes are the dominant cell type
What fills the space between adipocytes?
Areolar tissue, reticular tissue, and blood capillaries
What is white fat?
The only fat adults have, it provides thermal insulation and cushions organs and contributes to body contours
What is brown fat?
Only in fetuses, infants, and children. Color is from blood vessels and enzymes. Generates heat
How does adipose tissue look?
Like a net with a bunch of holes and some blood vessels where the “net” meets
What is cartilage?
Stiff connective tissue w/ flexible matrix
What are chondroblasts?
Cartilage cells that produce the matrix that will trap them
What are chondrocytes?
Cartilage cells that are trapped in lacunae (cavities)
What is the perichondrium?
A sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage
How does cartilage receive materials?
No blood vessels, gets nutrients and removes waste via diffusion
Types of cartilage?
Hyaline cartilage, fibrocartilage, and elastic cartilage
How does hyaline cartilage look?
Clear, glassy. FIne collagen fibers.
What does hyaline cartilage do?
Ease joint movement, hold airway open, move vocal chords, grow young long bones
Hyaline cartilage location?
Articular cartilage, costal cartilage, trachea, larynx, fetal skeleton
Elastic cartilage appearance?
Has an abundance of elastic fibers and is covered w/ perichondrium
What does elastic cartilage do?
Provide flexible, elastic support
Elastic cartilage locations?
External ear and epiglottis
Fibrocartilage appearance?
Cartilage w/ long, coarse bundles of collagen fibers. KInd of oval-ish, but some clumps too
Fibrocartilage function?
Resists compression and absorbs shock
Fibrocartilage locations?
Pubic symphysis, menisci, intervertebral discs
What type of tissue is bone?
Calcified connective tissue
Types of osseous tisse?
Spongy bone and compact bone
How does spongy bone look?
Porous. Delicate struts called trabeculae, covered by compact bone, found in heads of long bones and in middle of flat bones
How does compact bone look?
Dense, no visible spaces. More complex arrangement, cells and matrix surround vertical blood vessels. Like a lot of rings/cylinders
What are central canals?
In dense bone, vertical shafts that have blood vessels and nerves
What are concentric lamellae?
Onion-like layers around central canals in compact bone
What are osteons?
The central canal and its surrounding lamellae
What are osteocytes?
Mature bone cells within lacunae. The clumps on the rings
What are canaliculi?
Delicate canals radiating from each lacuna to its’ neighbors, allowing osteocytes to contact each other
What are lacunae?
Cavities
What is the periosteum?
Tough fibrous connective tissue covering whole bone
What kind of tissue is blood?
Fluid connective tissue
Purpose of blood?
Transport cells and dissolved matter like nutrients, ions, gases, and waste, from place to place
What is plasma?
The blood’s ground substance
What are erythrocytes?
Red blood cells that transport O2 and CO2
What are leukocytes?
White blood cells that defend against infection and disease
What are platelets?
Cell fragments involved in clotting
Define excitability
Ability to respond to stimuli by changing membrane potential
What is membrane potential?
Electrical charge difference that occurs across cell membrane
What happens w/ excitability in nerve cells?
Changes in voltage result in rapid transmission of signals to other cells
What happens w/ excitability in muscle cells?
Change in voltage results in contraction, shortening of the cell
What does nervous tissue do?
Specialized for communication by electrical and chemical signals
What do neurons do?
Detect stimuli, respond quickly, transmit coded info rapidly to other cells
What do neuroglia do?
Protect and assist neurons. More numerous than neurons
What is a neurosoma?
Cell body of neuron; houses nucleus and other organelles and controls protein synthesis
What are dendrites?
Short, branched processes on neuron. Receive signals from other cells and transmit messages to neurosoma
What are axons?
Long thing on neuron, sends outgoing signals to other cells
What is muscle tissue?
Elongated cells that are specialized to contract in response to stimulation. Exert physical forces on other tissues and organs
What does muscle tissue do?
Create movements, help w/ digestion, eliminate waste, help w/ breathing, help w/ blood circulation
Types of muscle tissue?
Skeletal, cardiac, and smooth
How does skeletal muscle look?
Long, striated tubes with oval nuclei.
Where is skeletal tissue and is it voluntary?
Attached to bone, voluntary
How does cardiac tissue look?
Short little rectangular fibers w/ nucleus in gap. Branched, meet at ends. Striated
Where is cardiac tissue found and is it voluntary?
Around the heart, and involuntary
How does smooth muscle look?
Diamond shaped kind of, with oval nuclei. Not striated
Where is smooth muscle located and is it voluntary?
In organs, and it is involuntary
What are cell junctions?
Connections between 2 cells
What do cell junctions allow?
Communication between cells, resisting of mechanical stress, and control over what moves between gaps
What is a tight junction?
A linkage between 2 adjacent cells by transmembrane cell-adhesion proteins. Seals off intercellular space
What is a desmosome?
A patch that holds cells together. Not continuous, substances pass them. Keeps cells from pulling apart.
What are hemidesmosomes?
Half desmosomes that anchor basal cells of an epithelium to underlying basement membrane
What are hemidesmosomes?
Half desmosomes that anchor basal cells of an epithelium to underlying basement membrane
What are gap junctions?
Formed by ring-like connexons, they let ions, nutrients, and solutes pass between cells
How do connexons look?
6 transmembrane proteins arranged like segments of an orange around a water-filled pore
What is a gland?
A cell or organ that secretes substances for use elsewhere in the body, or releases them for elimination from the body
What is a secretion?
Product useful to the body
What is an excretion?
A waste product
What are exocrine glands?
Glands that secrete things to the epithelium using a duct
What are endocrine glands?
Things that secrete hormones directly into the blood
What are serous glands?
Glands that make thin, watery secretions. Ex: sweat, milk, tears, digestive tissues
What are mucous glands?
Glands that make the glycoprotein mucin, which absorbs water to form mucus
What are mixed glands?
Glands w/ both serous and mucous cell types that produce a mixture of those 2 secretions
What is merocrine secretion?
Eccrine glands. Use vesicles that release secretion by exocytosis
What is apocrine secretion?
Lipid droplet covered by membrane and cytoplasm buds from cell surface
What is holocrine secretion?
Cells accumulate a product until they disintegrate
What is the cutaneous membrane?
Largest membrane in the body. External membrane. Epidermis and dermis
What is the mucous membrane?
Internal membrane, lines passages that open to external environment
What is the serous membrane?
Internal membrane, covers organs and lines walls of body cavities. Produces serous fluid
Sublayers of mucous membrane?
Epithelium, lamina propria, muscularis mucosa
Serous membrane structure?
Simple squamous epithelium resting on layer of areolar tissue
What is hyperplasia?
Growth through cell multiplication
What is hypertrophy?
Enlargement of preexisting cells (muscle and fat growth)
What is neoplasia?
Development of a tumor
What is differentiation?
Development of more specialized form and function by unspecialized tissue
What are stem cells?
Undifferentiated cells that are not yet performing a specialized function. Can mature into different types of cells
What are embryonic stem cells?
Pluripotent - can develop into any type of cell in the embryo
What are adult stem cells?
Stem cells in mature organs. Can be multipotent - can become different cell types, or can be unipotent - can only turn into 1 cell type
Define regeneration
Replacement of dead or damaged cells by same type of cell as before. Restores normal function
Define fibrosis
Replacement of damaged cells w/ scar tissue. Holds organs together, does not restore function
Stages of healing a wound?
1 - severed vessels bleed into cut. blood plasma comes in carrying antibodies and clotting proteins
2 - scab formation. blood clot and macrophages prevent infection
3 - granulation tissue forms. new capillaries sprout. clot is removed and new collagen comes in
4 - connective tissue undergoes fibrosis. epithelium regenerates
What is tissue engineering?
Artificial production of tissues and organs in a lab for implantation in human body
What is atrophy?
Shrinkage of a tissue through loss in cell size or number
Types of atrophy?
Senile and disuse
What is necrosis?
Pathological tissue death due to trauma, toxins, or infections
What is infarction necrosis?
Sudden death of tissue when blood supply is cut off
What is gangrene necrosis?
Necrosis due to insufficient blood supply (usually bc of infection)
What is apoptosis?
Programmed cell death. Occurs when they’re done w their purpose and their best option is to get out of the way
What process takes out cells in apoptosis?
Macrophages phagocytize them. The extracellular suicide signal binds receptor protein in plasma membrane called Fas, which activates endonuclease to chop up DNA and protease to destroy proteins
