Collections of specialized cells and cell products that perform a relatively limited number of functions
TISSUES
The study of tissues....
HISTOLOGY
The types of tissues (and their percentage)
1. Neural (2%)
2. Epithelial (3%)
3. Connective (45%)
4. Muscle (50%)
Tissue which carres information from one part of the body to another in the form of electrical impulses.
Neural Tissue
Tissue that covers exposed surfaces, lines internal passageways and chambers and forms glands
Epithelial tissue
Tissue that is specialized for contraction and includes the skeletal muscles of the body, the muscle of the heart and the muscular walls of hollow organs.
Muscle Tissue
Tissue which fills internal spaces, provides structural support for other tissues, transports materials within the body and stores energy reserves.
Connective Tissue
Epithelial Tissue:
Epithelia
layers of cells that cover internal or external surfaces
Epithelial Tissue:
Glands
structures made of cells that produce fluid secretions
4 Basic Functions of Epithelila Tissue
1. Protection
2. Transport
3. Secretion
4. Provide Sensation
Epithelial Tissue:
Epithelial:
1. Anything that has communication with the outside world: Body surface and lining of involutions
-skin, G.I.tract, respiratory tract, urogenital tracts
2. Lining of cavities and blood vessels and exocrine glands
-endothelium, mesothelium
Characteristics of Epithelia:
Glands- Structiure made of cells that produce secretions
Epithelia + Glands =
epithelial tissues
The term that refers to the presence of structural and functional differences between the exposed and attached surfaces
POLARITY
4 Characteristics of Epithelial
1. Polarity
2. Avascular
3. Regenerative
4. Cell attachment
Structure that produce fluid secretions
Glands
Characteristics of Epithelia:
2. Avascular
They lack blood vessels therefore obtain nutrients by diffustion or absorption across the exposed (apical) or attached (basal) epithelial surface
Characteristics of Epithelia:
1. Polarity
EXTRACELLULAR:
Apical- Where the cell is exposed to an internal/external enviroment
..... Cilia-(sweep debris) i.e. Respiratoy tract
..... Microvilli- (increase surface area 20 times) i.e. digestive tract
Lateral- contacts neighboring cells
Basal- contacts "underlying stuff"
Basolateral= lower sides and bottom
Characteristics of Epithelia:
3. Regenerative
Replace lost or damaged
Continual division of stem cells
Characteristics of Epithelia:
4. Cell Attachment: to neighboring cells and to underlying stuff via:
A. Intercellular cement: hyaluronic acid
B. Cell Adhesion Molecules (CAM)
C. Cell Juctions: tight, adheresn, gap junctions, and desmosomes (button & hemi)
Cilia or Microvilli? Urinary Tract
Microvilli ( Remember: Microvilli is abudant on surfaces where absorption or secretion takes place)
LUMEN- the central space within a duct or other internal passageway (the apcial surface of the epithelial cells are exposed to the lumen)
What is the underlying STUFF?
Basal Lamina
What are the 2 layers of the Basal Lamina?
1. Lamina lucida
2. Lamina densa
T/F Basement membrane is referred to as a intracellular matrix
False... its referred to as a EXTRAcellular matrix
Composed of protein fibers made by both above epithelial cells and underlying fibroblast of reticular lamina connective tissue
Basal Lamina
What is the basement membrane composed of?
1. Basal lamina (which includes lamina lucida and lamina densa)
and
2. Reticular Lamina (connective tissues)
Is the basal lamina the same as the basement membrane?
NO... basal lamina is part of the basement membrane but it is also comprised of the reticular lamina
Transmembrane proteins that tie the cytoskeleton to :
a. the cytoskeleton of neighboring celss
b. proteins in the underlying extracellular matrix
Cell Adhesion Molecules (CAM)
Cell Adhesion Molecules (CAMs)
Transmembrane proteins that tie the cytoskeleton (actin, microtubules) to:
a. cytoskeleton of neighboring cells
b. proteins in the underlying extracellular matrix
Can also serve as receptors
Contribute to cell junctions
CAM Classifcation:
Cadherins- link cytoskeletons of neighboring cells
Integrins- Link the cytoskeleton to proteins in matrix
Selectins- transient cell-cell binding in bloodstream
Where on the cell are tight junctions found?
Lateral Surfaces (remember they attach a cell to another one)
Cell Junctions:
TIGHT JUNCTIONS:
Cell membranes of adjacent cells are tightly stitched together via interlocking proteins
-NO passage of H2O or solutes between cells - depends on the junctional proteins
Limits movement of integral proteins
What limits movement of integral proteins?
Tight Junctions
What type of cell junctions are found in the blood brain barrier?
Tight junctions
The 4 Types of Cell Junctions:
1. Tight Junctions
2. Adherens Junctions (aka adahesion belt)
3. Gap Junctions
4. Desmosomes
Type of cell junction that is usually found in epithelial tissue below a tight junction
Adherens junction
Specialized areas of the cell membrane that attach a cell to another cell and/or extracellular materials
Cell Junctions
The type of tissue that covers exposed surfaces and lines internal passageways and body cavities is:
C. epithelial
Interlocking channel proteins that hold adjacent cells together at gap junctions.
Connexons
What type of cell junctions are essential for coordination of muscle cell contractions?
Gap Junctions
Epithelial Tissue are classified by
1. Shape (flat vs. cubes vs columns)
2. # of layers (one vs. many)
Epithelial Tissue: # of layers
1. Simple - 1 layer
---Protection is not the priority (located inside the body)
---Important of diffusion of "vitals" (lungs, blood vessels)
2. Stratified- several layers of cells
---PROTECTION is PRIORITY (body surface)
Simple or Stratified? Blood Vessels?
Simple
Simple or Stratified? Surface of the skin?
Stratified (remember PROTECTION is priority)
What is the most delicate type of epithelium type?
Simple Squamous
The simple squamous epithelium lining the inner surface of the heart and all blood vessels
Endothelium
The simple squamous epithelium that lines the ventral body cavity
Mesothelium
What type of cell?
Simple Cuboidal
what type of epithelia cell?
Stratified Cuboidal
What are the 3 types of Columnar Epithelial Types?
1. Simple
2. Pseudostratified
3. Stratified
What type of epithelium cell?
Stratified Columnar Epithelium
Pseudostratified Columnar Epithelium
Simple Columnar Epithelium
Simple Squamous Epithelium
Stratified Squamous Epithelium
Provides limited protection and occurs where secretion or absoprtion takes place (i.e. glands, ducts)
simple cuboidal epthelium
Epithelium that tolerates repeated cycles of stretching/recoil (i.e. bladder)
transitional (its name is transitional because it changes as stretching occurs)
Trasitional epithelia in the bladder looks stratified when empty but when full it looks _______________
simple
2 Types of Glandular Epithelia
1. Exocrine Glands
2. Endocrine Glands
Another name for ductless glands
Endocrine glands
Glandular Epithelia:
1. Endocrine Glands ("ductless") - release secretions into interstitial fluids--> blood stream
-Secretions=Hormones
-Thyroid and Pituitary
2. Exocrine Glands- release secretions into ducts that open onto epithelial surfaces
-enzymes entering digestive tract, sweat, milk, tears
What type of Cell Junction? Lateral surfaces of cells that require rapid intercellular communication
GAP junctions
What type of Cell junctions? Cells subject to mechanical stress
Desmosomes
Cell Junctions: Desmosomes
Concentration of CAM + intermediate filaments of cytoskeleton
Dense Area
Cell Junctions: Tight Junctions
Cell membranes of adjacent cells are tightly stiched togehter via interlocking proteins
No passage of H2O or solutes between cells- depends on the junctional proteins
Limits movement of integral proteins
Location: Lateral surfaces
ie) Digestive Tract, Blood Brain Barrier
Cell Junctions: Adherens Junctions
Ususually found in epithelial tissue, beow a tight junction- an adhesion belt encircles neighboring cell together
Adhesion belt- Cadherins (CAM) connect a web of cytoplasmic actin n
cell #1 to a web of cytoplasmic actin in cell #2- actin of adjacent
cells is connected-cells can work togetherLocation: Lateral Surfacesie) Cardiac muscle, digestive tract
Cell Junctions: Gap Junctions
Allow for movement of small molecules and ions into adjacent cells and between cell membranes (via the GAP)
Connexons- interlocking channel proteins that hold adjacent cells togehter at gap junctions
-open to form a hydrophilic pore & allow passage of ions & small molecules
Location: Lateral surfaces of cells that require rapid intercellular communication
What are the 3 MAIN components of Connective Tissue Proper?
1. Cells
2. Ground Substance
3. Fibers
Connective Tissue Proper: Components
CELLS
Fibroblast-most abudant main source of ground substance and fibers
Messenchymal cells- Connective Tissue Stem Cells
Adipocytes- Energy storage, insulation
Melanocytes- make & store melanin
Immune Cells- Lymphocytes, macrophages
What is the name for connective tissue stem cells?
Mesenchymal Cells
Which of the following is a fat cell found in connective tissue?
C. Adipocytes
Which of the following connective tissue cells synthesizes and stores melanin?
E. Melanocytes
2 types of Immune Cells
Lymphocytes and Macrophages
Connective Tissue Proper: Ground Substance
composed of PROTEOGLYCANS
Proteoglycans= proteins + glycosaminoglycans
**composition of proteoglycans is varied in each connective tissue type**
Connective Tissue Proper: Components
Ground Substance
Viscous: impedes movement
Water soluble: diffusion of O2
Fills spaces between cells and cells& fibers
________________ fills the spaces between cells and surrounds connective tissue fibers
Ground Substance
Connective Tissue Proper: Components
Fibers
-Collagen
-Elastic
-Reticular
Connective Tissue Proper: GROUND SUBSTANCE
Types of Glycosaminoglycans:
1. Hyaluronic Acid: Intercellular cement. Aggregates proteins (la brea tar pits for microbes)
2. Chondroitin Sulfate- found in cartilage
3. Dermatan Sulfate- found in dermis
4. Keratan Sulfate- found in cornea
Which of the following is found in cartilage?
D. Chondroitin Sulfate
Which of the following is found in dermis?
D. Dematan Sulfate
Which of the following is found in cornea?
C. Keratan Sulfate
Which of the following aggregates proteins (an intercellular cement)?
B. Hyaluronic Acid
Connective Tissue Proper: FIBERS
Collagen
-Most abundant protein in body
----35% of all protein
----40 different types of collagen molecules
-Most abundant fiber
----Long, straight, unbranched
----Resistant to undirectional stress
----Braided like rope= stronger than steel
----Key to strength of ligaments and tendons
Which of the following fiber is long, straight, and unbranched?
C. Collagen Fibers
Which of the following is is braided like a rope and is stronger than steel?
B. Collagen Fibers
Connective Tissue Proper: Fibers
Elastic Fibers
-Contain the protein elastin
---Branch and wavy fibers
---Stretches and returns to original shape
ie) vessels, alveoli, tendon, ligaments
Connective Tissue Proper: Fibers
Reticular Fibers
-Contain same protein subunits as collagen but different arrangement
-Synthesized by reticular cells (aka fibroblasts)
-Resist forces applied from many directoins
-Form an interwoven network called stroma
Common location/function: stabilize the functional cells (parenchyma) of organs, the position of b.v. & nerves within organs. Component of reticular tissue
Reticular Fibers form an interwoven network called ___________
Stroma
Parenchyma
functional cells of organs
Connective Tissue Proper: Loose vs. Dense
Detemined by the amount and types of cells & fibers
Loose- fibers creat loose, open framework (found in areolar, adipose and reticular tissue)
Dense- Fibers densely packed ( dense regular, dense irregular, and elastic)
Support cells
Interconnect cells
Organ Protection
Energy storage
Fluid connective Tissue: Blood vs. Lymph Blood---> Circulatory System
Cells :
----Red Blood Cells: Transport O2 ----Platelets: Clotting
-----White Blood Cells: Immune
Fluid connective Tissue: Blood vs. Lymph Lymph---> Lymphatic System
-Matrix: lymph (+soluble fibers)
-Cells
------White blood cells (lymphocytes) hang out in lymph nodes & monitor the body for infection
Which of the following cells found in blood protects us from infection and disease?
B. White Blood Cells
Which of the following cells found in blood transports oxygen?
D. Red Blood Cells
Which of the following cells found in blood seals breaks in the endothelial lining?
A. Platelets ( REMEMBER: CLOTTING=sealing)
the 4 types of MEMBRANES:
1. Mucous
2. Synovial
3. Cutaneous
4. Serous
Epithelium + Connective Tissue=
Membrane
Which of the following membranes lines the passageways that communicate with the outsie digestive, respiratory or urogenital?
D. Mucous
Synovial Membranes:
Decrease friction between artculating bones (joints)
- Lubricated by synovial fluid
Which of the following membranes covers the exterior of body surface?
B. Cutaneous (aka SKIN) -its THICK, DRY and WATER resistant
Serous Membrane:
Lines "sealed" body cavities and covers organs to minimize friction
-lubricated by transudate
Transudate lubricates which of the following membranes?
B. Serous
Membrane Transport: OSMOSIS
- The concentration of individual ions IS NOT equal actroos the membrane (ie. more Na+ outside the cell)
- TOTAL CONCENTRATION (mol/L) of ALL ions/molecules intracellular equals the TOTAL CONCENTRATION of ALL ions/molecules extracellular
Membrane Transport: OSMOSIS
- Cell membrane is freelypermeable to water
- Cell membrane is only selectively permeable to solutes
-Solutes have a concentration gradient, therefore a gradeint also exists for water
-Water follows solutes and dilutes them so that the total solute concentration (mol/L) is equal inside and outside of the cell
What happens when theres is more solutes on the outside of the cell?
Water leaves the cell to dilute them and make the total solute concentation equal inside and outside
Membrane Transport: Osmosis:
Osmosis: Diffusion of H2O across cell membrane via aquaporins
Osmolarity: total SOLUTE concentration in an aqueous solution
What influences the movement of water in/out of the cell?
Unequal osmolarity across the membrane (aka solute gradient)
Total solute concentration in an aqueous solution
Osmolarity
Diffusion of water across cell membrane via aquaporins
Osmosis
OSMOSIS:
Water MOVES:
Most dilute---> most concentrated solution
Lowest (solute)---> highest (solute)
Low solute potential---> High Solute potential
Lower Osmolarity ---> higher Osmolarity
High water potential ---> low water potential
Purest water --->less pure water
WHERE SODIUM GOES, so goes Water
Water moves: CHOOSE THE CORRECT ONE
D. Most dilute---> Most concentrated solution
The pressure created by water when it moves across a membrane to dilute a solute of high concentration.
Osmotic Pressure
Osmotic Pressure: the pressure created by water when it moves across a membrane to dilute a solute of high concentration
-pressure of water required o maintain molarity equilibrium
-develops in the solution that originally contained the HIGH of solute
-the # of soulute particles or concentration of solute (osmolarity of the solution) determines the osmotic pressure
-opposed by hydrostatic pressure
What kind of pressure opposes osmotic pressure?
Hydrostatic pressure
What determines the osmotic pressure?
The # of solute particles or concentration of solute (osmolarity of the solution)
TONICITY: how osmolarity effects a cell
Isotonic Solution
Solutions have similar osmolarity
Hypotonic Solution
Extracellular fluid has lower (hypo) osmolarity (water moves into the cell wehre omolarity is higher).... cells will lyse
Hypertonic Solution
extracellular fluids has higher (hyper) osmolarity (water moves out of cell to where osmolarity is higher) cells will creanate
