Chapter 5: Tissues Flashcards
what are the four types of tissues?
epithelial, connective, muscle, nervous
what are epithelial tissues?
typically tissues lining the body
what are the functions of epithelial cells?
protection, coverage, lining; filters bad, absorbs good, manufactures secretions and excretions
what are characteristics of epithelial cells?
they need to be arranged in a certain way, connect to each other closely, avascular, and some are innervated
how do epithelial face when on an apical surface?
faces the lumen, body cavity, or extremity
how do epithelial face when on a basal surface?
faces basement membrane
how do epithelial cells receive nutrients considering they are avascular?
they receive nutrients through neighboring connective tissue
what are tight epithelial junctions?
plasma membranes attach directly with one another using a protein
what are epithelial desmosomes?
connection plaques extend into the cytoplasm of each cell via tonofilaments
what are epithelial gap junctions?
connexons: channels by which cells share cytoplasm; allows for exchange of ions, nutrients, and electrical signals
What is another name for the basement membrane?
the basal lamina
what does the basement membrane do?
functions as an epithelial cell foundation; provides a support structure; separates epithelial cells from connective tissues underneath
what is the basement membrane made up of?
collagen fibers, produced by epithelial cells
how do epithelial cells receive their nutrients?
through diffusion from the connective tissue across the basement membrane into the cells
what specialized surfaces can epithelial tissue have?
brush boarder, cilia, keratin
what does the brush boarder do for epithelial tissue
increases surface area for absorption
where are brush borders most commonly found?
in the intestine
what does cilia do for epithelial tissues?
move substances across the surface of the cell
where are cilia most commonly found?
on the oviduct or trachea
what does keratin do for epithelial tissues
act as another layer of protection, typically waterproof
where is keratin most commonly found?
in the skin cells
how is one layer of epithelial cells characterized?
as simple
how is more than one layer of epithelial cells characterized?
as stratified
what are the different shapes of epithelial cells?
squamous, cuboidal, columnar, transitional
where do simple squamous epithelial cells live in the body?
linings of cavities in the body
What does simple squamous epithelium do?
allow for easier passage of gas and fluids
What does simple cuboidal epithelium do?
involved with absorption and secretion; hormone production
Where does simple cuboidal epithelium live?
lining the stomach and intestines; ducts
What is simple columnar epithelium do?
involved with absorption and secretion
where is simple columnar epithelium found?
lining intestines and ducts
What cells does columnar epithelium contain
absorptive cell; has microvilli
goblet cell; looks like wine glass, produces protective layer of mucous
What is stratified squamous epithelium?
several layers of squamous cells
where is stratified squamous epithelium found?
areas of high mechanical stress
ex: mouth, esophagus, vagina, rectum
Where do cells form in stratified squamous epithelium?
at basal surface from cuboidal cells
Why are there two layers of cuboidal cells in stratified epithelium?
to provide greater protection to structures underneath the basement membrane
where is stratified cuboidal epithelium found?
in large excretory ducts
ex: mammary glands, salivary glands
What epithelium is found between simple and stratified?
Pseudostratified columnar epithelium
What is different about pseudostratified epithelium?
it is a type of simple epithelium, cells appear to be stratified, often ciliated
Where is pseudostratified epithelium commonly found?
in the respiratory tract
What is transitional epithelium
very stretchy, forming a completely leak-proof membrane
where is transitional epithelium typically found?
in the urinary bladder
what are glands?
made up of cells that manufacture a secretion
what are endocrine glands?
glands that secrete hormones into the bloodstream or lymphatic system
what are exocrine glands?
glands that secrete substances onto nearby surfaces
What are different methods of secretions?
merocrine, apocrine, holocrine
What are different types of secretions?
serous, mucous, mixed
What are merocrine secretions?
exocytosis of vesicles (making of vesicles)
What are apocrine secretions?
when the cell sacrifices its entire apex
what are holocrine secretions?
when the entire cell is sacrificed; it explodes and dies
what is serous secretions made of?
enzymes, super watery
what is mucous secretions made of?
contains glycoproteins, very thick
what is mixed secretions made of?
a combination of serous and mucous secretions
What are the functions of connective tissues?
provides the framework of the body, transports substances, provides healing and protection
What are the three main characteristics of connective tissue?
composed primarily of extracellular matrix, vascularized, most abundant tissue type in the body
What are the 3 main components in connective tissue?
ground substance, extracellular fibers, cells
What is ground substance?
the medium through which cells exchange nutrients and waste with the bloodstream
what are extracellular fibers?
collagenous, reticular, elastic
where do fixed cells remain?
in connective tissue
what does fibroblasts do?
manufactures and secretes fibers and ground substance
what do adipocytes do?
store lipid molecules; acts as cushions for protection
what do macrophages do?
can be fixed or wandering; enters and exits connective tissue providing access for the immune system
what are leukocytes?
white blood cells, engulfs pathogens and produces antibodies
what are mast cells?
responsible for allergic and inflammatory responses; histamine and heprin
what is loose connective tissue?
extracellular matrix organized into a loose weave; like a 3D net
what is areolar connective tissue?
the most abundant connective tissue; contains all 3 fibers, ground substance of hyaluronic acid water mix, and fibroblasts and wandering cells
what is adipose connective tissue?
commonly known as fat, areolar tissue predominantly made up of adipocytes; highly vascularized
what is reticular connective tissue?
same as areolar, just contains reticular fibers; forms a stroma
what is dense connective tissue?
densely packed arrangement of collagen fibers
what is dense regular connective tissue?
tightly packed parallel collagen fibers; relatively avascular; can withstand force in a single direction
what do tendons connect?
muscle to bone
what do ligaments connect?
bone to bone
what is dense irregular connective tissue?
collagen fibers arranged in thick bundles, interwoven randomly, can withstand force in several directions, found in the dermis
what is elastic connective tissue?
primarily made of elastic fibers in parallel and interwoven arrangements, stretchy, found in nuchal ligament
What is specialized connective tissue?
cartilage, bone, blood
what is cartilage?
tougher than dense connective tissue, more flexible than bone, not innervated
where is cartilage found?
within joints and certain structures (ear, nose, vocal cords)
What does cartilage do?
act as a shock absorber, provides protection between bones, provides framework for bones growing in animals
what cell is associated with cartilage?
chondrocyte
what is hyaline cartilage?
collagen fibers, found in articular cartilage and growth plates
what is elastic cartilage?
elastic fibers, found in ear pinna and epiglottis
what is fibrocartilage?
merge of hyaline cartilage and dense connective tissue, found in intervertebral discs, stifle, pelvis symphasis
what is bone?
the most rigid type of connective tissue, heavily vascularized
what is bones’ matrix?
calcium phosphate and calcium carbonate
what cells are associated with the bone?
osteoblasts, osteocytes, osteoclasts
what fibers are in bone?
collagen fibers
what does blood do?
carry nutrients and gases throughout the body
what cells are found in blood?
a variety; erythrocytes, leukocytes, thrombocytes
what is the matrix of blood?
plasma
when are fibers found in blood?
when blood clots
what proteins are arranged into microfilaments in muscle tissue?
actin and myosin
what is special about muscle tissue?
cells can make themselves shorter or longer; strong enough to move tissues around them (blood, bone, soft tissue )
what is special about muscle tissue?
cells can make themselves shorter or longer; strong enough to move tissues around them (blood, bone, soft tissue)
what are the three types of muscle tissue?
skeletal, smooth, and cardiac
What are characteristics of skeletal muscle?
it can be consciously controlled (voluntary movement), has a lot of mitochondria and nuclei, is striated
what are characteristics of smooth muscle?
has small spindle-like cells, nonstriated, involuntary movement
what are characteristics of cardiac muscle?
only exists in the heart, creates a network of branching cells, is striated and involuntary but takes suggestions
What does nervous tissue do?
transmits electrical and chemical signals
what are neurons?
longest cells in the body
what makes up a neuron?
the axon - nucleus; carries signals away from the body
the perikaryon - cell body
the dendrite - receives impulses; carries signals towards body
What are neurological cells?
cells that serve as a support cell to neurons
what do neurological cells do?
isolate the conducting membrane, provide supportive framework, phagocytize waste, supply nutrients
what is inflammation ?
the body’s quick initial response to injury; a way to limit further damage and eliminate harmful agents,
(T/F) all stages of tissue repair occur simotaneously
true
What are the steps within inflammation?
- capillary changes
- plasma enters
- clot formation
- phagocytosis
- capillaries return to normal
what happens during step 1 of inflammation
initial vasoconstriction: reduced hemorrhage;
followed by vasodilation: Increase blood flow to the area;
histamine and heparin are released to increase capillary permeability
what happens during step 2 of inflammation
swelling from fluid entering the area, contains enzymes, antibodies, and other proteins
what happens during step 3 of inflammation
fibrinogen -> fibrin
fibrin forms a net to collect thrombocytes (platelets)
what happens during step 4 of inflammation
WBCs move in to clean up bacteria + foreign material; dying WBCs can form pus
what happens during step 5 of inflammation
histamine and heparin disperse, swelling, redness, and warmth subsides
How does tissue repair?
slowly, starts with granulation tissue, progresses to regeneration of lost tissue or fibrosis
where does granulation tissue form?
beneath a blood clot
when does the formation of granulation tissue start?
as son as injury occurs
hat can slow down the formation of granulation tissue?
infectious agents or foreign material
what results in proud flesh?
abnormal growth of excessive granulation tissue
What is epithelialization?
epithelial cells at the edge of a wound quickly divide
overtime, what is granulated tissue replaced with?
fibrous scar tissue; not very functional but strong, will shrink overtime
what are the different types of wound healing?
first intention and second intention
what is first intention wound healing?
occurs when wound edges are in close contact; no granulation tissue forms; heals in 10-14 days
what is second intention wound healing?
occurs when wound edges do not meet; granulation and scar tissue form; wound contraction occurs; takes longer to heal
