Unit 2: Histology Flashcards
(154 cards)
1
Q
Define Tissues
A
collection of cells & cell products; that perform specific limited functions
2
Q
4 Basic Tissue Types;
A
- Muscle
- Nervous
- Connective
- Epithelial
3
Q
Define Epithelial tissue function
A
covers exposed surfaces (lining)
lines internal pathways
forms glands
4
Q
Define Connective Tissue function
A
fills internal spaces- packing materia;
supports other tissues- bone & cartilage
transport materials- blood and lymph
stores energy - adipose tissue- fat
extracellular matrix: non-cellular, non-living parts of CT; can have protein fibers
5
Q
Define muscle tissue function
A
contraction (in blood vessels & organs)- does not put itself back
6
Q
name 3 types of muscle tissue & function
A
skeletal- voluntary
cardiac- found in walls of hollow organs
smooth
7
Q
Define function of neural tissue
A
conducting electrical impulses
8
Q
2 different types of epithelial tissue
A
- epithelial
- glandular
9
Q
Define epithelia
A
layers of cells covering internal or external surfaces
ex. epidermis
10
Q
define glands
A
structures that produce secretion
11
Q
What are the 5 characteristics of epithelia?
A
- Cellularity
- polarity
- attachment
- avascularity
- regeneration
12
Q
Define the characteristic of epithelial: cellularity
A
When cells are closely bound together (so they can regulate what can enter the body) by structures called- cell junctions
other tissue types are separated by ECM
13
Q
Define the characteristic of epithelial: Polarity
A
refers to the presence of structural and functional differences
14
Q
What are the two sides of polarity found in epithelia?
A
apical surface- top surface
basolateral surface- bottom and the sides
- attached to another cell or basement membrane and the sides which contract neighboring cells
15
Q
Define the characteristic of epithelial: Attachment
A
epithelia are anchored to a layer of extracellular material- basal lamina or basement membrane (
16
Q
Define the characteristic of epithelial: Avascularity
A
No blood vessels- must obtain nutrients through diffusion to absorption usually through CT
17
Q
Define the characteristic of epithelial: regeneration
A
the rate of cell division & regeneration is higher than other tissues
- constantly getting rid of top layer- self-cleaning epidermis
new epidermis every 4-6 weeks
epithelial lining: wear and tear
18
Q
List teh 4 functions of epithelial tissue
A
- provide physical protection
- control permeability
- provide sensation
- provide specialized functions
19
Q
How does epithelial tissue provide physical protection?
A
the epidermin prptects the inside of the body from abrasions, microbes, chemicals and dehydration
20
Q
What are some examples of epithelial tissue monitoring permeability?
A
The epithelial lining of intestine, kidneys and lungs monitors what’s going in and out
21
Q
How does the epithelial tissue produce sensation?
A
through highly specialized cells
ex. taste buds, eyes and ears
22
Q
What is an example of epithelial tissue providing highly specialized functions?
A
glandular epithelial tissues
23
Q
List 3 ways in how epithelial cells specialize
A
- moving or pushing materials over the epithelial tissue
- absorption
- secretion
24
Q
Give an example of moving or pushing materials over the epithelial tissue?
A
function of ciliated epithelial
e.g. lining of respiratory passageways to move mucus
25
Define cilia
hair-life orgalles that wave or beat (rhythmic movement)
- cell has 250 cilia that beat in a coordinate manner
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Example of epithelial tissue role in absorption
absorbing nutrients from intestine
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example of epithelial tissue roles in secretion
mucus
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What is absorption and secretion aided by? Define it and what do they do
Microvilli- tiny bumps of cell membrane
increases SA and absorbs more stuff= efficient
ex. lining of small intestine
29
Explain the concept of intracellular connections to epithelial tissue
gives strength to epithelial tissue & help them communicate with each other
30
What does intracellular connections involve ? (2)
1. extensive areas of adjacent cell membranes
2. specialized cell junctions
31
Define cell adhesion molecules
transmembrane proteins that interconnect large areas of adjacent cell membranes
- can bind to each other or the basement membrane
32
Name 3 catgeories of cell junctions
1. tight junction
2. gap junctions
3. desmosomes
a. spot desmosomes
b. hemidesmosomes
33
define cell junctions
specialized areas of the plasma membrane that attach a cell to another cell or to extracellular materials
34
define tight junction
between apical portions of adjacent cells
- bound tightly -->prevents water and other substances from leaking b/w the cells
- useful when epithelium lines a tube e.g. intestine
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define gap junctions
allow rapid communication b/w the 2 connected cells- communication helps coordinate function
e.g. beating of cilila
- found in cells where communication takes place
e.g. heart muscles & contractions fo smooth muscle cells
- 2 neighboring cells held together by channel; proteins
-allow ions and small molecules to pass cell to cell
36
Define desmosomes
ensure stretching or twisting- very stronng
e.g. superficial layers of ski
- skin peels due to it
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define spot desmosomes
ties adjacent cells together
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define hemidesmosomes
attach a cell to extracellular structures such as protein fibers in the basement membrane
39
Define basement membrane
made of layers of proteins that strengthen epithelia
-help form a barrier b/w epithelia & underlying tissue
40
What is classification of epithelia based on?
based off of cell shape
# of layers
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What are 3 epithelia cell shapes? w/ description & ex
squamos- thin and flat
cuboidal- squarish
columnar- tall slender rectangle
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What are the 2 # of layers for epithelia? w/ description & ex
stratified- several layers of cells ex. callus
simple- a single layer of cells ex. oxygen diffusion
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What is simple epithelium good for? w/ ex.
where substances need to be absorbed through the epithelium
e.g. lining of lungs, lining of intestines
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What is stratified epithelia good for? w/ ex
good for areas that need protection from wear and tear & friction
e.gi epidermis, lining of thorat
45
Define germinative cells
type of stem cells that epithelial cells grow from; located near the basement membrane
46
Defne glands
collection of epithelial cells that produces secretion
47
Define endocrine glands
secretes chemical messengers called hormones which get released into bodily fluids
- ductless glands
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Define exocrine glands
release secretions into ducts that open onto an epithelial surface
- ducts empty onto the skin surface or an epithelium lining
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Examples of exocrine glands
perspiration fo skin, tears, mucus, milk--> mammary glands, saliva, enzymes entering the digestive tract
50
List the 3 modes of secretion
1. merocrine secretion
2. apocrine secretion
3. holocrine secretion
51
Describe merocrine secretion
most common form of secretion
product packaged into secretory vesicles & released from the vesicles by exocytosis
52
Describe apocrine secretion
"apo" apical portion of the cell (top)
products is released when the apical portion of the cell pinches off and breaks down
some cytoplasm is lost w. the secretory product
- the cell can regenerate a new apical region & start over r
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Example of apocrine secretion
cells of mammary glands release milk this way
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How would you differentiate between apocrine secretion and merocrine secretion?
You would look for cytoplasm to differentiate from merocrine
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Describe holocrine secretion
product is released when the cells burst which kills the gland cell; destroys the whole gland cell
- gland cell gets replaced with division of stem cells (germinative cells)
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Ex of holocrine secretion
cells of sebaceous gland--> sebum; oil glands in skin
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list 2 TYPES of secretions
1. serous secretions
2. Mucus glands
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Describe serous secretions
watery solutions that contain proteins- enzymes
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ex of serous secretions
gastric chief cells
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describe mucous secretions
the gland cells secretes molecules called mucins--> which mix w. water to form mucus
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ex. of mucuous secretions
various digestive glands produce mucus
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Function of mucus
protect the digestive tract from harsh digestive juices
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Goblet cells define
the only unicellular exocrine glands; secretes mucins
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define mesenchyme
what ct arrise from an embryonic tissue
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what are 3 characteristic of CT?
1. specialized cells
2. extracellular protein fibers
3. fluid extracellular ground substance
--> extracellular matrix
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difference between CT and ET
Et lines passageways that lead to the outside worlds
Ct is always inside
ET is avascular
CT is vascular (except cartilage)
both has sensory receptors
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define ground substance
thicker and stickier than normal ECM fluid
68
Define matrix & describe
noncellular non-living parts of CT
-made of protein fibers & ground substance
- made by CT cells
Makes ups most of the tissue volume
martix differs with different Ct
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list 3 classifications of CT
1. connective tissue proper (CTP)
2. Fluid connective tissue
3. Supporting CT
70
define CTP
connect & protect
what tendons and ligaments are made out of
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define and give an ex. of fluid connective tissue
2- blood & lymph
transport things in body
watery matric w/ dissolved porteins --> can be transformed into solid form for blood clotting
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give ex. of supporting ct
bone and cartilage
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List 7 cells of CTP
fibroblast, adipocytes, mesenchymal cells, macrophages, mast cells, melanocytes, and lymphocytes
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Define fibroblast
most common cell type in CTP
- produce ground substance & extracellular protein fibers - a lot of protein fibers is collagen
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define adipocytes
store energy in form of lipid molecule
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define mesenchymal cells
stem cells, can divide to make fibroblasts, adipocytes, or other CT cells
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define macrophage and identify 2 types & define
white blood cell (WBC); engulf & destroy pathogens and other stuff, dead cells
free macrophages- move like amoeba
fixed macrophage
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define mast cells
trigger local inflammation by releasing chemicals
e.g. histamines
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define melanocytes
produce melanin- brown pigmentation in skin
specifically around nuclei to protect the DNA
- UV rays make vitamin D
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define lymphocyte
WBC's --> specific defenses
basis for immunity and vaccines; include T- cells and B-cells
plasma cells aka plasma B- cells make antibodies
81
List 3 fibers in CTP
1. collagen fibers
2. reticular fibers
3. elastic fibers
82
define collagen fibers and e.g
| what are they a major component of?
give e.g.
major component of tendons and ligaments
gives strength to many tissues
e.g. skin bones
83
define reticular fibers
forms a branched network to support structure of organs
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define elastic fibers
similar to collagen fibers - made of protein elastin --> stretches and bounces back to original state
-rare compared to collagen fibers
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e.g. of elastic fiber
ligaments that interconnect the vertebrae
86
list the 2 categories of CTP
1. loose CT
2. Dense CT
87
Define loose CT
more ground substance
fewer protein fibers e.g. adipose tissue
the packaging of material of the body - fills in the spaces cushioning the body
87
list the 3 types of loose CT
1. areolar tissue
2. adipose tissue
3. reticular tissue
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define areolar tissue
least specialized & most generic type of tissue
viscous (thick) ground substance
- has some elastic fibers
- holds blood vessels and capillary beds
89
e.g. of areolar tissue
find under the skin; subcutaneous layer
90
Define adipose tisue
adipocytes; store fat, insulation & slowly heat loss
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What happens to adipocytes during fat loss or gain?
expand and shrink based off fat loss and gain
(same thing with muscle cells)
don't divide
92
define reticular tissue
reticular fibers; complex 3D network
provides support & maintains the shape of organs
93
e.g. of reticular tissue
spleen, liver, lymph nodes, bone marrow
94
Define Dense CT & e.g.
more fibers
less ground substance
e.g. what tendons and ligaments are made out of
-tightly packet w/ collagen and/or collagen fibers
95
list 3 categories of dense CT
1. Dense regular CT
2. dense irregular CT
3. elastci tissue
96
define dense regular CT
tightly packed parallel collagen fibers
-> has strength to withstand forces coming from one direction
- good for tendons and ligaments- stresses on these structures come from predictable directions
97
define tendons
attach muscles to bones
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define ligaments
attach bones ot bones
ligaments stabilize position for organs
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define aponeuroses
made up of broad, flat sheets of dense regular CT
-also attach muscles to bones
100
define dense irregular CT & e.g.
interwoven networks of collagen fibers; no organized pattern;strength in all directions
e.g. skin (leather)
forms capsules & sheaths that surrounds organs
101
define periosteum
around bones
102
define perichondrium
around cartilages
103
define elastic tissue & e.g.
dense regular CT dominated by elastic fibers (instead of collagen)
e.g. in the elastic ligaments that connect vertebrae
104
What is the plasma?
matrix of the blood
105
3 types of blood cells
RBCs
WBCs
platelets
106
define RBCs
| how much do they take up the volume of blood?
erythrocytes; make up approximately 1/2 volume of blood
carry CO2 in blood
107
define WBCs
leukocytes
- 20 different types; various immune function
108
define platelet
not cells; cell fragments
sticky- good for blood clotting
109
define lymph
a fluid collected from interstitial space ( space b/w cell in tissues)
flows through lymphatic vessels & closely monitored by immune system
eventually becomes part of blood plasma when it returns to large veins near the heart
110
list 3 major subdivisions of ECF (extracellular fluid)
1. plasma
2. interstitial fluid
3. lympth
111
what is the origin of interstitial fluid?
when blood flows through capillaries blood pressure forces water & small solutes through the walls of capillaries
112
define interstitial fluid
bathes cells in tissues
113
where does lymph end up?
2 large lymphatic vessels located under the clavicle (collarbone)
goes to subclavian veins- goes to blood & becomes plasma
114
Calcified define?
Bone made rigid by calcium & other minerals
115
define cartilage
ground substances is very thick gel material
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Where are chondrocytes located?
lacuna- a scooped out area w/in the thick gel matrix
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describe cartilage
avascular (unusual for tissues) & heats poorly
gets O2 and nutrients by slow diffusion through the thick, dense matrix
118
list 3 types of cartilage
1. hyalin cartilage
2. elastic cartilages
3. fibro cartilage
119
define hyaline cartilage
glossy; the most common type
tough yet somewhat flexible
120
e.g. of hyaline cartilage
trachea and nasal
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define elastic cartilage
supporting but bends easily
found in the external ear
ear- pinna or auricles
epigottis- flap that covers the larynx
122
define fibrocartilage
very tough- the toughest cartilage
- prevents bone ot bone contact
123
e.g. of fibrocartilage
in knee joints, in the intervertebral discs- cartilage b/w the vertebrae
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2 types of growth of cartilage
interstitial growth
appositional growth
125
define interstitial growth
cell division & additional matrix from within the interior of the cartilage
- womb & throughout childhood
126
define appositional growth
cell division & additional matricx around the outside surface
- used to repair damaged cartilage in adulthood
127
what is bone also called?
osseous tissue
128
what is 2/3 of the bone matrix?
mineral portion; calcium salts
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what is 1/3 of the bone matrix?
collagen fibers- bone can bend before fracturing; resists shattering
130
Where are bone cells called and where do they reside"?
osteocytes ; small chambers called lacunae (same as chondrocytes)
131
How are osteocytes arranged?
arranged in circular layers around central canals- contain small blood vessels w/in the bone matrix
132
define canaliculi
bone cells access the blood supply through small channels that run through bone matrix
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Role & description of tissue membranes
line or cover bone sufaces
- consist of an epithelial layer w/ a supporting layer of CT underneath - areolar tissue
134
Nam the 4 types of tissue membranes
1. mucous membranes
2. serous membranes
3. the cutaneous membrane
4. synovial membrane
135
define mucous membranes,
lines passageways that connect to the outside world and keeps the surface moist w/ mucus
136
e.g. of mucous membranes lining___
digestive, respiratory, urinary, repro tratcs
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What is mucous produced by>
goblet cells or multicellular glands
138
How does mucous membrane facilitate absorption?
by absorbing O2 in the lungs
139
define serous membranes
line sealed internal areas of the ventral body cavity
thin, transparent but strong
140
what does serous membranes produce and what does it do?
produce a slippery fluid= transudate
- minimizes wear and tear in ventral cavity
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define the cutaneous membrane
skin- covers body surface
stratified-squamous epithelial- epidermis
142
What is below the epidermis?
dense irregular Ct & areolar tissue= dermis
143
Differences between the cutaneous membrane and the other membranes
skin is thick, somewhat waterproof, and relatively dry
144
Define synovial membranes & what does it produce
line moving joint cavities
produce synovial fluid-> lubricates and protects the ends of bone in joints
145
Why do bone cells heal faster than cartilage?
because it has access to bone supply unlike cartilage
146
Define fasciae and function
CT layers and wrappings which support and surround organs
maintain the position of roagsn
provides routes for blood vessels, lymphatics, and nerves
147
Name 3 types of fascia
1. superficial fascia
2. deep fascia
3. subserous fascia
148
define superficial fascia
aka hypodermis aka subcutaneous layer
layer of fat below the skin; separates the skin from underlying tissues & organs
149
Why do injection go in this layer?
there are no muscles or tendons
it is squishy fat loaded w/ blood vessels
150
what is superficial fascia made up of?
areolar and adipose tissue
151
Define deep fascia
made up of dense irregular CT- tough capsules around organs, bones, tendons, ligaments, cartilages and muscles
152
What function does deep fascia do?
its leathery wrapping paper
does a lot of the framework (more collagen)
does not hold the structure
protects and holds in place
153
Define subserous fascia
made up of areolar tissue; separate deep fascia from the serous membranes (lines body cavities)
