The basics: on tissues
Tissue-is a group of cells with similar structure and function, plus 

the extra cellular substances located between the cells.
Histology- The microscope study of tissue structure.
4 basic tissue types:
	Epithelial, connective, muscular, and nervous.
Epithelium- covers surfaces of the body or forms glands. 
Most epithelial have a 
Free Surface, - which is “not in contact with other cells, 
and a 
Basement Membrane,  -which attaches the epithelial cells to underlying 

tissue.
	The basement membrane, is a mixture of carbohydrates and proteins 

secreted by epithelial cells and cells of the underlying tissue.
Epithelia are classified according to the number of cell layers and their 

shape.
Simple Epithelium- consists of a single layer of cells.
Stratified Epithelium- consists of more layer of epithelial cells, some 

sit on top of each other.
Categories of epithelium based on cell shape are:
	Squamous-  flat
	Cuboidal- Cube like
	Columnar-  Tall and thin
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Simple squamous epithelium-  single layer of flat like cells.  Mostly used 

for Respiratory passage because of the thin structure. Simple squamous 

epithelium cells are found in nasal cavities, or trachea, lungs, also 

used on alveoli, because of their thin structure, simple squamous 

epithelium allows oxygen to come in the body, and carbon dioxide to be 

breathed out.


Simple Cuboidal epithelium- a single layer of a cube like cells. These cells 

have a greater volume, and contain more organelles, than simple squamous

epithelium. The organelles produce carrier molecules, and ATP, for 

facilitated diffusion, and active transport, so it can be regulated. Used 

in the kidneys , waste is excreted from the cells, (Urine) and the 

nutrients are absorbed.
Simple columnar epithelium- a single layer of cells, that are tall and thin, 

They are able to complete complex functions. For example in the layer of

the intestine, the epithelium produce an enzyme to carry out digestion. 

They then absorb the nutrients by either facilitated diffusion, active 

transport or diffusion.



	Stratified Squamous Epithelium- Is many layers of different types of 

cells. 

The very deepest layer are Cuboidal, or columnar; which are able to 

multiply, and push 	up the cells to the top layer, while the bottom 
layers are being created. Such as, skin, if the top layer of the tissue 

gets rubbed off, the bottom layers can replace it. Skin protects 

against abrasion this way.


Pseudostratified columnar epithelium- “Pseudo-Fake”  Consists of one 
layer of epithelium that appears to be more than one and all the cells are 

attached to the basement membrane. Some cells reach the free surface  

while others do not, creating the false impression of more than one layer. 

It is found in respiratory passages, such as the nasal cavity, trachea 

or bronchi.
Transitional Epithelium- A special type of stratified epithelium that is able 

to greatly stretch. In the outstretched state, consists of  5 more or

layers of cuboidal, or columnar cells that are dome shaped on the free 

surface. When they are stretched become more cuboidal or squamous shaped 

and the number of cell layers decreases. It is found in organisms that 

tend to be ‘stretchy’ such as the urinary bladder.
     Mucus- protects the lining of the stomach from 

the acids produced in the stomach. 

If the Mucus is not produced, this can result in an ulceration of the 

stomach lining in the epithelial cells. Simple columnar cells line the

 wall of the stomach.



Free Cell Surfaces
Smooth surfaces reduce friction. For example, the lining of the blood vessels 


is simple squamous epithelium, the free cell surface is smooth to prevent 
friction, for easier blood flow.



Microvilli - Cylindrical extensions of the free surface of  a cell. They serve 

the purpose to provide more surface area. They are found on cells that are

 involved in absorption or secretion (such as the lining of the small 

intestine.



Cilia- Propel materials along the surface of the cells. The nasal cavity and 

trachea are lined with pseudostratified columnar ciliated epithelium.



Goblet cells- Intermixed with the ciliated cells, are these specialized mucus 

producing cells.


(the nose) as the ciliated cells stimulate movement of mucus, the entrapped 

particles move along with the cilia pushing them to the back of the throat,

 where it is all swallowed. The swallowing of mucus helps keep the respiratory 
passages clean.
	


Cell Connections
Epithelial cells are connected in several ways.

Tight Junctions- bind adjacent cells together and form permeability 

 barriers. they prevent passage of materials between cells. Found in 

the intestines. It’s easier to regulate materials this way. 

“selective permeability”



Desmosomes-  Mechanical links that bind cells together. Used in stratified 

squamous. Found being subjected to stress.  
Gap Junctions- Small channels connected between cells, allow cells to 

regulate and communicate among each other.


GLANDS
Gland- a single cell ore multi cellular structure that secretes substances 

onto a surface, into a cavity or into the blood. 

Exocrine- glands with ducts
     Simple- with ducts that have no branches

     Compound- with ducts that have many branches

           Tubular- or expanded into a sac like structure called

           an acinus (Acinus or Alveolus) 




Endocrine have no ducts and empty their secretions directly into he 

blood. These secretions called hormones, are carried by the blood to 

other parts of the body.

A) unicellular (goblet cells in mucous membranes)

B)Simple tubular (sweat glands and stomach glands)

C) simple acinar or alveolar end in a saclike structure (Sebaceous glands)

D) Compound tubular (duodenal glands)

E) compound acinar or alveolar (pancreas)



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Connective Tissue

Connective tissue- joins together other tissues.

Extracellular Matrix- 
	1) protein
	2) ground substance consisting of non fibrous protein and other molecules
	(Ground substances: shapeless background against which cells and collagen 

fibers are seen in a light microscope.
    
3) fluid


3 types of Protein fibers:
    
1) collagen fibers- resemble microscopic ropes flexible and resistant

 stretching.

	2) Reticular fibers- very fine short collagen fibers that branch to form a 
supporting network.
	3) Elastic Fibers- have a structure similar to coiled metal bed springs, 

after being stretched, elastic fibers, have the ability to recoil to their o

riginal shape.  “Hint: bed coils”



Proteoglycans- resemble the limbs of  pine trees with proteins forming the branches 

and polysaccharides forming the pine needles. this structure enables proteoglycans 

to trap large quantities of water between the polysaccharides.


Blast Cells- Produce the matrix

Cyte cells- maintain it.

Clast cells- break it down for remodeling. 
     
(for example osteoblasts form bone, osteocytes maintain bone, and osteoclasts 
break down bown)



Immunity

Macrophages- are large cells capable of moving about and ingesting foreign 

substances.

Mast cells- are non-motile cells that release chemicals promoting inflammation



CLASSIFICATION:
Dense connective tissue- has an extracellular matrix consisting mostly of collagen

 fibers.
	Fibroblasts- which are responsible for the production of the collagen fiber.
 		(IE. tendons, ligaments, dermis (Hypodermis) some structures have 

elastic fibers IE: vocal chords)
	
Areolar (loose)- In areolar tissues protein fibers are widely scattered, there 

is loose packing around organs, glands, muscles and nerves
	Adipose Tissue:  has a matrix with protein fibers, not really connective 

tissue, structurally similar, stores energy and pads and protects.
	Cartilage: composed of cartilage cells, chondrocytes, located in spaces 

called lacunae within an extensive matrix.
	A) collagen gives cartilage flexibility and strength. Proteoglycans trap 

water and help cartilage to spring back. Cartilage provides support springs 

back when stretched, does not heal quickly.



Types of cartilage:
	1) Hyline- most abundant, found on the ends of bones, between ribs and 

sternum.
	2) Fibro cartilage- more collagen then hyline. 
Resistant to compression to pulling and tearing found in between vertebrae.
	3) elastic cartilage- elastic fibers, collagen and proteoglycans






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Test Questions




1) Distinguish between ontogeny recapitulates philogeny and form follows function.
 Relate form follows function to one of the e-tissues.




2) What is the difference between parietal and visceral?




3) List the eleven systems of the human body and give two organs and two 
functions of each.




4) Define the following cell organelles:

Ribosome:
Smooth E.R.:
Lysosome:
Cell Membrane:
Golgi Apparatus:
Mitochondria:
Vesicle:
Nucleus:

5) What is the difference between active and passive transport?




6) Draw and label the five glands. Also, give the location where these 
glands might be found.




7)Describe a proteoglycan and discuss how its structure is related to its 
function.




8)Define the following:



Blast:
Cyte:
Clast:
Macrophage:
Mast:

9) Describe each of the four connective tissues mentioned in class.



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Power point Review! IF you have power point you can view this file 

for a short review over the eleven systems of the body. 
Click here (Anatomy_Presentation.ppt) 
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