5th ( summary ) including lab and many points about
glandular epithelium 
# After reading the covering epithelium from book , you must put in mind the table (4-3)
P.84 in your book
NOTES :
# The mesothelium is a membrane that forms the lining of several body cavities:
the pleura (thoracic cavity), peritoneum (abdominal cavity including the mesentery)
and pericardium (heart sac) Mesothelial tissue also surrounds the male internal
reproductive organs (the tunica vaginalis testis) and covers the internal reproductive
organs of women (the tunica serosa uteri)Mesothelium that covers the internal organs is
called visceral mesothelium, while the layer that covers the body walls is called the parietal
mesothelium.  It is a form of simple squamous epithelium .
#The endothelium is the thin layer of cells that lines the interior surface of blood
vessels and lymphatic vessels,[1] forming an interface between
circulating blood or lymph in the lumen and the rest of the vessel wall. The cells that form
the endothelium are called endothelial cells. Endothelial cells in direct contact with blood
are called vascular endothelial cells, whereas those in direct contact with lymph are known
as lymphatic endothelial cells.
Now we will talk about the secretory epithelial and glands 
* * * * * * * * * * *  Read these info before starting ( But when you finish this summary refer
and save them   ) .
# epithelial cells that function to produce and secrete various macro-molecules may occur
in epithelia with other major functions or comprise specialized organs called glands .
# Products to be secreted are generally stored in the cells within small membrane bound
vesicles called secretory glands.
# Exocrine gland is distinguished by the fact that it excretes its essential product by way of
a duct to some environment external to itself, be it either inside the body or on a surface of
the body Examples of exocrine glands include the sweat glands, salivary
glands, mammary glands, and liver.
# Endocrine glands are glands of the endocrine system that secrete their
products, hormones, directly into the blood rather than through a duct. The major glands of
the endocrine system include the pineal gland ,pituitary
gland, pancreas, ovaries, testes, thyroid gland, parathyroid
gland, hypothalamus, gastrointestinal tract and adrenal glands.
______________________________________________ ___________________________
CONCENTRATE OK !!! #
The epithelial tissue is always connected to C.T , and it behaves same C.T behavior " same
behavior of the connective tissue that underlies it "  therefore to change the behavior of
epithelial tissue, we must affect of its C.T  when we affect on the C.T  The connective
tissue will send message to epithelial tissue  the result : the epithelial tissue will change
its type ( for-example from original type to stratified or keratinized )
# If we transfer the epithelial tissue from its original place to another  it takes its
instructions from C.T underlying it   that means it takes the new C.T instructions NOT
old (means NOT C.T of first place  ) << ma feo 29el  >>
BUT if we transfer (the epithelial tissue from its original place to another with its C.T  it
will continue taking its instructions from its C.T << a9eel wa gad3 >>
# When the C.T sends a message to epithelial tissue to change its type in response to many
different factors >>> Fore-example : changing to stratified >>> the epithelial cells will start
to proliferate and differentiate ( increasing their numbers ) .
# # # But usually the C.T send " inductive forces " >>> therefore the basal lamina is
restricted  >>> the cells will increase their numbers and lengthen and they will not be at
straight line  >>> basal lamina will down "toward to C.T " >>> The epithelial cells will form
a clusters because their proliferation 
# Put in mind << in this case if the basal lamina stays straight , it will becomes stratified
(((means without inductive forces ))) >> .
# The continuation of basal lamina that downs toward to C.T >>> the epithelial cells in
centre part on the basal lamina are undifferentiated and degenerated Because lacking of
access the nutrients from C.T and the spaces will form " these spaces are called ducts " 
  >>> But the cells in the peripheral parts will differentiate to be secretory cells
>>>>>>>>>> Therefore we get Exocrine glands   
CONCENTRATE OK !!! #
- uterine glands <<< lined by simple columnar epithelium ( some are ciliated and others are
not  ) >>> are found in the functional layer of the uterine endometrium . Their appearance
varies during the menstrual cycle.
# Their C.T ( the connective tissue of these glands or of the uterus because they are same )
is composed of two layers ( 1- upper layer is called stratum functionalis 2- lower layer is
called stratum basalis )
# During the menstrual cycle >>> the blood vessels supplying the epithelial cells are
affected by the level of progesterone in the blood ( means the nutrients are affected by
progesterone levels ) >>> when the level of progesterone decreases >>> the smooth
muscles in the uterus contractile >>>> the blood vessels will contract and close >>>
therefore the area supplied by these blood vessels will down because lack of nutrients  

# Note : the area that will down is ( stratum functionalis and epithelium layer )
>>> When the level of progesterone returns normal >>> the epithelial layer and C.T will
return to normal state ( they are regenerated    ) >>> when forming " the complete
covered to the uterus cavity " , the secretory substances that rise to the surface have
yellowish or brownish color   
# Note : Uterus glands by their secretions , they will return the epithelium layer to the
normal state " By regenerations " because their original from the surface and they try to up
the surface    .
# The females know that when the color of secretions is yellowish or brownish (means
away from bloody color ) this sign of the menstrual cycle  .
# Note : if we make a wound about "1cm " in skin of someone ( to test the spontaneously
healing ) >>> usually if we leave the wound without sewing >>> the sweat glands in the
superficial fascia under the wound directly will rise to the surface and close the wound (
remember that these glands always try to rise to the surface >>> and here they heal the
wound because they are originated from epithelium    ) .
# The development of exocrine sweat glands is result of retraction of the basal lamina and
the proliferation of the cells that line over it    ( remember the instructions of the C.T )
   >>> the central part of cells become ducts and peripheral parts become secretory
parts  >>>> and the ducts will reach the secretions to the surface 
# Note :exocrine glands secret mucus ( usually harmful substances such as hydrochloric
acid )  therefore they should be away from the circuit  through the circuit we will find "
the hormonal locally activating substances "  these substances work in local areas to
prepare the cells and save them from the secretion of harmful substances " fa3el 5eer :p "
# this process is very important because the harmful substances such as hydrochloric acid
, if they reach the cells , they will damage them    .
______________________________________________________________________________
The endocrine glands
# Their developments are same to the exocrine glands 
# They lose the connection to their original epithelium and therefore lack ducts  >>> thin
–walled blood vessels adjacent to the endocrine cells absorb their secreted hormone
products for transport in blood to target cells throughout the body   
The differences between the endocrine and exocrine glands
 Endocrine glands have no ducts. They secrete what is called hormone. The hormone is
released in the blood stream and is circulated in the blood where it finds a particular organ,
called target organ, to which goes and influences its physiology.
An exocrine gland has duct, which is the conduit for the release of products produced by it.
The product is discharged in a place where the product of the gland shows its action.
 The amount of blood in the endocrine glands is bigger than in the exocrine ( because the
endocrine secret their substances into the blood circulation as hormones  )
The mixed glands ( such as pancreas )
# example (pancreas gland ) It consists of two part ( endocrine part) producing several
important hormones, including insulin, glucagon , somatostatin, and pancreatic
polypeptide which circulate in the blood ( these endocrine secretions form 1000,000 units
in the pancreas ) .
(exocrine part means pancreas is also a digestive organ, secreting pancreatic
juice containing digestive enzymes that assist digestion and absorption of nutrients in
the small intestine. These enzymes help to further break down the carbohydrates, proteins,
and lipids in the chyme .
# example : testis " mixed gland "  sperms ( exocrine secretions ) #
 interstitial cells of Leydig, are found adjacent to the seminiferous tubulesin the testicle.
They
produce testosterone in the presence of luteinizing hormone (LH) (endocrine secretions ) .
# example : Ovary  ovum is considered exocrine secretion  But ( the Corpus luteum
that secretes progesterone and moderate levels of estradiol and inhibin A ) is considered
endocrine secretions 
Note : in the last examples , each example (gland) contains some cells that considered
exocrine , and contains other cells are considered endocrine  but  in this example (Liver
) , each cell itself is considered exocrine and endocrine at same time 
# example : Liver  each cell of liver is considered endocrine and exocrine at same time .
____________________________________________________________________________
# The classification of exocrine glands according to the structure
Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used
to classify the gland.

The duct portion may be branched (called compound exocrine gland ) or un-branched (called
simple exocrine gland ).

The glandular portion may be tubular or acinar, or may be a mix of the two (called tubuloacinar).
If the glandular portion branches, then the gland is called a branched gland.
_____________________________________________________________
# Exocrine glands are classified as either unicellular or multi-cellular.
1) Unicellular glands are the simplest in structure. In unicellular exocrine glands, the
secretory component consists of single cells distributed among other nonsecretory cells. A
typical example is the goblet cell, a mucus-secreting cell positioned among other columnar
cells .
dGoblet cells are located in the surface lining and glands of the intestines and in certain
passages of the respiratory tract.
# Goblet cells are glandular simple columnar epithelial cells whose function is to secrete gel
forming mucins, which are the major component of mucus. They use
both apocrine and merocrine methods for secretion  these cells consists of two parts ( apical
part that called optea dilated that secrets the mucus –basal part that is called stem that
contains nucleus and this part is stained under L.M )
2 ) Multicellular glands are composed of more than one cell. They exhibit varying
degrees of complexity. Their structural organization allows sub-classification according to
the arrangement of the secretory cells (parenchyma) and the presence or absence of
branching of the duct elements.
The simplest arrangement of a multicellular gland is a cellular sheet in which each
surface cell is a secretory cell. For example, the lining of the stomach and its gastric pits is
a sheet of mucus-secreting cells .

Other multi-cellular glands typically form tubular invaginations from the surface. The end pieces
of the gland contain the secretory cells; the portion of the gland connecting the secretory cells
to the surface serves as a duct. If the duct is unbranched, the gland is called simple; if the duct
is branched, it is called compound. If the secretory portion is shaped like a tube, the gland
is tubular; if it is shaped like a flask, the gland is alveolar or acinar; if the tube ends in a saclike
dilation, the gland is tubuloalveolar. Tubular secretory portions may be straight, branched, or
coiled; alveolar portions may be single or branched. Various combinations of duct and
secretory portion shapes are found in the body.
____________________________________________________________________
# CONCENTRATE OK !
# Note : the clear cells : A cell, especially a neoplastic one, containing abundant glycogen or
other material that is not stained by hematoxylin or eosin, so that the cytoplasm appears clear
histologically
# In the digestive tract , when the scientists studied the tissue , they found the cells that were
not stained with H and E stains  >>> These cells were in different shapes and different shapes
of nucleus and their lengths were different  >>> they were considered as Clear cells 
# To stain these cells , the scientists discovered many substances inside them ( such as
adenosine –peroxidaze – carboxylaze ) , and according to kind of these substances  the
scientists made a stain to study these cells under microscopy 
# After studying these cell , they were called " ABUD cells "
# The Abudoma : oma means cancer  is a tumor originates from the adud cells  part of the
Doctors consider this is risky tumor but others do not   the different opinions about this
tumor refers to these cells are originated from several origins  But the common things
between these cells are : 1) they give Positive in the staining 2) they are clear cells 
# another scientist found the cells that are not contained into the organ   the secretory
substances from them are similar to the secretory substances secreted from nervous system
But the secretion in these cells is into the blood circulation   these cells are called DNES "
diffused neuroendocrine system cells "  these cells are classified as unicellular endocrine
cells  the other name for them is ABUD   
_________________________________________________________________________
# The classification of glands according to " biochemistry scientists " this classification
depends on the secretory substances form the gland 
Serous cells :" watery substances secreted " excrete proteins , often enzymes. Examples
include chief cells and Paneth cells ( they are composed of large cuboidal cells "pyramidal
cells "  their nucleus occupied a basal position  their cytoplasm appears basophilic under
L.M  most of the cytoplasm are granules ) .
 Mucous cells : " viscous substances secreted " excrete mucus. Examples include Brunner's
glands, esophageal glands, and pyloric glands  " with special stain , the apical part of the
cytoplasma appears bony " means with spaces "
## ## ## in the last structure ( the mucus cell appears and in the bottom we recognize serious
cells (‫ ) خلية نصف قمرية‬ this serious cell facilities excretion the substances from the glands ,
supporting the mucus gland and concentration on the antibodies therefore they increase the
Immunity in the area tat secretes the substances .
 Mixed glands excrete both protein and mucus " watery and viscous substances secreted "
Examples include the salivary glands, although the parotid gland is serous , the sublingual
gland is mucous, and the submandibular gland is both serous and mucous. 
# In the mixed gland here  1) seriomucus mixed gland " means the serious substances
secreted are bigger than mucus "  2) mucuserious mixed gland " means the mucus
substances secreted are bigger than the serious "
_____________________________________________________________________
# Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found
in glandular
epithelium as a thin layer above the basement membrane but generally beneath the luminal cells.
 In the Dr. opinion : these cells are security parts surrounding the basal lamina and
fusing the epithelium OR these cells are basal lamina itself 
 Their function : the contraction of these cells leads to evacuate the secretory part  the
removing if these cells leads to delay of the secretory part But it will continue its working 
Sometimes these cells are described as basket cells ( because they have many
processes involved with epithelial cells )
______________________________________________________________________.
# The exocrine glands are named apocrine glands, holocrine glands, or merocrine glands based on
how their products are excreted. #
1) The Merocrine secretion : is the most common method of proteins and involves typical
exocytosis of proteins and involves typical exocytosis of proteins or glycoproteins from
membrane-bound vesicles ( the examples : all the sweat glands in the body ) .
2) The Holocrine secretion : in this process cells accumulate products as they mature and
undergo terminal cell differentiation ,culminating in complete cell disruption with release of
the product and cell debris into the glands lumen  this is best seen in the sebaceous
glands of the skin .
( the examples : Sebaceous glands ) .
Note : these cells work during the fetal life in response to influence of sexual hormones in
the body of the mother  But after the labor " after 3-4 hours , when the sexual hormones
from the body of the mother finished  , these glands stop working , and they return to
work after puberty ( By sexual hormones secretion " - these glands depend on the
presence of sexual hormones    .
# Acne vulgaris (or simply acne) ‫ حب الشباب‬is related to holocrine gland 
# its substances secreted are large to secrete by the exocytosis process .
3) The Apocrine glands : the products here accumulate at cells apical ends, portions of
which are then extruded to release the product together with a bit of cytoplasm and
plasma membrane  this is the mechanism by which droplets of lipid are secreted in the
mammary gland .
( the examples : female breast in the feeding stage  the milk in the breast contains
carbohydrate , proteins and lipids But the substances suckled by infants are surrounded in
the female breast by plasma membrane  this means that milk will contain cells from
plasma membrane O.o  For this ----------->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
‫ال تستطيع الشركات أن تقلّد كل المواد من البروتينات وغيرها في الحليب الصناعي ألنها ال تستطيع تقليد البالزما عشان هيك بيحكو‬
‫حليب األم ال يمكن تقليده‬

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# Apocrine secretion is less damaging to the gland than holocrine secretion (which destroys a cell)
but more damaging than merocrine secretion (exocytosis).
# Notice in these structures how the hair follicle opens to pass sweat from the gland through the
duct to surface part  ( in the lab open the glandular epithelium and see the structures that same
to these 
__
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