Download Class XIX Tissues and organ systems I – Epithelial tissues To Grow

Class XIX
Tissues and organ systems I – Epithelial tissues
To Grow and Differentiate:
We need to convert materials from the environment into
components of organism
...what do we need to make?
Structural elements of living organisms are composed of:
1. Nucleic acids (DNA, RNA and their variants)
2. Proteins
3. Fats
4. Carbohydrates
1. Carbon
2. Hydrogen
3. Oxygen
4. Nitrogen
(5. Other elements)
(N,P,F,C)
(N,P,F,C)
(N,P,F,C)
(N,P)
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Option 1: Make your molecules
Option 2: Get your molecules
PLANTS
(make their own protein, fat, carbohydrate and nucleic acids)
ANIMALS
(get most of their own protein, fat, carbohydrate and nucleic acids)
Can not make:
-Essential amino acids (Met, Val, His, Thr, Phe, Leu, Ile, Typ, Lys)
- Essential fatty acids (linoleic acid)
-Require large amounts of minerals
(Calcium, Iron, etc.)
Therefore, animals need to ingest (eat) another living organisms
which make or contains these substances
..once you eat,
you’ll have to digest !
Almost all “polymers” in
nature, need to be
separated into monomers,
if they are to be used for
growth by animals.
Fig. 21.2b (Campbell 5th ed.)
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Fig. 21.4
What “digests” organic molecules?
Detergent
ACID
Enzymes
Fig. 21.11a
(Enzymes: Mouth-saliva; Pancreas)
(Acid: Stomach-acid; Enzymes: Pancreas)
(Enzymes: Pancreas)
(Detergent: Liver-bile; Enzymes: Pancreas)
Table 21.11
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Animals can’t “make” all of their own molecules,
and in addition:
Herbivores: digest all that they ingest effectively
Carnivores: digest some of what they ingest effectively
Fig 21.13a
We use the molecules we digest to make 3 tissue types:
-Ephitelial tissues
(Endoderm derived)
-Connetive tissues and Muscle tissue
(Mesoderm derived)
-Neuronal tissues
(Ectoderm derived)
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1. Epithelial tissues
Fig. 20.4
1. Epithelial tissues
Lumen (or exterior)
symmetrically packed cells
2a. Connective tissues
“binds and supports tissues”
Fig. 20.5
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2a. Connective tissues
Organized as a mass
2b. Muscle tissue
Fig. 20.6
“functions in movement”
2b. Muscle tissue
organized in parallel sheets or “fibers”
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3. Neural tissue
Formed by neurons with branching
extensions; function in transmitting
neural signals
1. Epithelial tissues
L. 17-1
1. Epithelial tissues
stomach
intestine
mouth
bladder
eye
L. 19-8
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1. Epithelial tissues
Intestine epithelium
K+
L. 11-29
1. Epithelial tissues
Stomach epithelium (parietal cells)
L. 11-30
How can we “see” a parietal cell?
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Using antibodies specific for parietal cells we can “see”
these cells utilizing immunohistochemistry
How can we “make” antibodies that recognize
parietal cells?
To be able to study these cells or to be able to make
antibodies to proteins that are specifically found on
“parietal” cells, we have to use “pure” parietal cells.
But since these are normal cells, if we collect cells from the
stomach and try to grow them in the laboratory (in tissue
culture plates) they will dye.
We therefore transfer an “oncogene” into a normal parietal
cell or grow a cell from a “parietal cell cancer”. The cell
then becomes immortal and it grows to form a uniform cell
population. It becomes a “parietal cell-line”
We can make cell-lines from cells of almost any tissue
We can inject this cell into mice, which will make antibodies
to proteins of the parietal cells.
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We can then test the antibody the mouse makes by
Western analysis
(-)
(+)
Labeled antibody
(w. radioactivity or fluorescence)
specific for a protein found in parietal-cells
(-)
We think that the
protein the
antibodies recognize
is a pump protein.
How can we prove
this is the case?
(+)
By “screening” a cDNA library we can identify the gene
encoding the “parietal-cell specific protein” our antibody
recognizes
mRNA
cDNA
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By “screening” a cDNA library we can identify the gene
encoding the “parietal-cell specific protein” our antibody
recognizes
By “screening” a cDNA library we can identify the gene
encoding the “parietal-cell specific protein” our antibody
recognizes
By “screening” a cDNA library we can identify the gene
encoding the “parietal-cell specific protein” our antibody
recognizes
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Once the cell harboring the plasmid is
identified the plasmid can be purified..
..and sequence analyzed
5’-ATGTCGGCTACTGCCTAGCAGGCGC…..
by comparing this sequence to all the known
cDNA sequences at NCBI by BLAST we can
identify which gene product this is..
..or, if the sequence corresponds to a gene whose
function is unknown, then we can make the protein of this
gene and purify it.
Lyse
Centrifugate
Purify protein by chromatography
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perform X-ray crystallography
We can observe the crystal structure of the protein and by
comparing its shape to that of others we can predict the
function of the protein
We can observe the crystal structure of the protein and by
comparing its shape to that of others we can predict the
function of the protein
We can observe the crystal structure of the protein and by
comparing its shape to that of others we can predict the
function of the protein
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Required reading:
Legends and explanations associated with
figures covered in class
1. Stomach contains 0.1M HCl. How does the epithelium
of the stomach protect itself from HCl?
2. We learned how glucose and Na++ are absorbed by the
intestinal epithelial cell. How are aminoacids,
nucleotides, fats and other ions absorbed?
3. What is “transcytosis”?
4. Other than parietal cells, the epithelium of the stomach
contains at least 4 other epithelial cells. What are these
and what are their functions?
5. Even though there is acid in the stomach it does not kill
some bacteria that constitute the “flora” of our gut. The
large intestine, on the other hand, is full of bacteria.
What are these bacteria and what is their function?
6. When patients are given antibiotics, they might develop
diarrhea because the drugs kill bacteria that are
normally present in the large intestine. Why should this
cause diarrhea?
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