Download Chapter 3b

Chapter 3b
Compartmentation:
Cells and Tissues
Golgi Complex
• Membranes surrounded by vesicles
• Protein modification
• Protein packaging into secretory vesicles
Golgi Complex
Vesicle
Lumen
(a)
Figure 3-18a
Golgi Complex
Figure 3-18b
Cytoplasmic Vesicles
• Secretory vesicles
• Released from cell
• Lysosomes
• Digestive enzymes
• Peroxisomes
• Hydrogen peroxide
• Detoxification
• Fatty acid degradation
Cytoplasmic Vesicles
• Lysosomes and peroxisomes
Mitochondrion
Lysosomes
Peroxisomes
Figure 3-19
Nucleus
•
•
•
•
Nuclear envelope
Nuclear pore complex
Chromatin
Nucleoli
• Control RNA synthesis
Nucleus
Nuclear envelope is a
double membrane that
separates the nucleus
from the cytoplasm.
Nucleolus contains
DNA that controls
synthesis of
ribosomal RNA.
Chromatin is DNA
and protein.
Nuclear pores
regulate movement
of material into and
out of the nucleus.
Figure 3-20
Primary Tissue Types
• Epithelial
• Lining and glands
• Connective
• Protection, support and storage
• Muscle
• movements
• Nervous
• Communication, sense internal and external
environment
Histology
• Four types of tissues:
1) Epithelial
1) Lining
2) glands
2) Connective
1) Protection
2) Storage
3) connections
3) Muscle
1) movement
4) Nervous
1) Sense
2) communication
Epithelial Tissues: Cell Junctions and CAMs
• Cell to cell
• Gap junction
• Tight junction
• Anchoring junction
Cell Junctions and CAMs
Table 3-3
Types of Cell-Cell Junctions
Tight junctions prevent
movement between cells.
Claudin and
occludin proteins
Adherens junction
Intercellular space
Desmosomes anchor
cells to each other.
Cytosol
Cell
1
Cell
2
Cell membrane
(a) Tight junction
Figure 3-21a
Types of Cell-Cell Junctions
Tight junctions
prevent movement
between cells.
Adherens junction
Cadherin proteins
Cell membrane
Plaque glycoproteins
Desmosomes anchor
cells to each other.
Cytosol
Intercellular space
Intermediate filament
(b) Desmosome, an anchoring junction
Figure 3-21b
Types of Cell-Cell Junctions
Heart muscle has
gap junctions.
Cytosol
Connexin
proteins
Clusters of
gap junctions
create cytoplasmic
bridges between
adjacent cells.
Intercellular
space
Cell membrane
(c) Gap junction
Figure 3-21c
Cell Junctions and CAMs
• A map of cell junctions
CELL JUNCTIONS
Function
Communicating
Occluding
Location
Cell-cell junctions
Type
Gap junction
Tight junction
Membrane
protein
Connexin
Claudin,
occludin
Cytoskeleton
fiber
Matrix
protein
Anchoring
Actin
Cell-matrix junctions
Adherens junction
Desmosome
Focal adhesion
Cadherin
Actin
Hemidesmosome
Integrin
Intermediate
filaments
Actin
Keratin
(intermediate
filaments)
Fibronectin and
other proteins
Laminin
Figure 3-22
Epithelial Tissue: Structure
• Basal lamina
• Basement membrane
• Cells in contact
• junctions
Epithelial Tissue: Structure
Epithelial cells attach to
the basal lamina using cell
adhesion molecules.
Basal lamina is an acellular
matrix layer that is secreted
by the epithelial cells.
Underlying tissue
Figure 3-23
Epithelial Tissue: Functions based on Layers, Shape
and Features
Table 3-4
Distribution of Epithelia in the Body
Integumentary System
Respiratory
system
Circulatory
system
Digestive
system
Cells
KEY
exchange
Musculoskeletal
system
Urinary
system
secretion
secretory
epithelium
exchange epithelium
Reproductive
system
transporting epithelium
protective epithelium
ciliated epithelium
Figure 3-24
Exchange Epithelia
Capillary epithelium
Blood
Pore
Extracellular fluid
(a) Leaky exchange epithelium allows movement through
gaps between the cells.
Figure 3-25a
Transporting Epithelia
Apical
membrane
Lumen of intestine or kidney
Tight
junction
Basolateral
membrane
Transporting
epithelial
cell
Extracellular fluid
(b) Tight junctions in a transporting epithelium prevent
movement between adjacent cells. Substances must
instead pass through the epithelial cell, crossing two
phospholipid cell membranes as they do so.
Figure 3-25b
Ciliated and Protective Epithelia
Cilia
Microvilli
Golgi apparatus
Nucleus
Mitochondria
Basement membrane
(a) Ciliated epithelium lining the airways
Figure 3-26a
Ciliated and Protective Epithelia
Cilia
Microvilli
(b) Scanning electron micrograph showing
ciliated cells mixed with cells covered with
shorter microvilli
Figure 3-26b
Cilia and smoking
• The following series of slides
illustrate microscopic changes
that happen when a person
smokes. The first slide is
showing an illustrated blow-up
of the normal lining of the
bronchus. On the top we see
the cilia, labeled (H). They are
attached to columnar cells,
labeled (I). The cilia sweep
the mucous produced in the
goblet cells, labeled (J) as well
as mucous coming from
deeper glands within the lungs
and the particulate matter
trapped in the mucous. The
bottom layer of cells, labeled
(L) are the basal cells.
Cilia and smoking
• Below we start to see the
changes that occur as people
begin to smoke. You will see
that the columnar cells are
starting to be crowded out and
displaced by additional layers
of basal cells.
• Not only are fewer cilia present
but the ones that are still
functioning are doing so at a
much lower level of
efficiency. Many chemicals in
tobacco smoke are toxic to
cilia, first slowing them down,
soon paralyzing them all
together and then destroying
them.
Cilia and smoking
•
•
As you see with the cilia actions being
diminished, mucous starts to build up
in the small airways making it harder
for the smoker to breathe and causing
the characteristic smokers cough in
order to clear out the airways.
Eventually though, the ciliated
columnar cells are totally
displaced. As can be seen below
ominous changes have taken
place. Not only is the smoker more
prone to infection from the loss of the
cleansing mechanism of the cilia, but
these abnormal cells (O) are
cancerous squamous cells. These
cells will eventually break through the
basement membrane wall and invade
into underlying lung tissue and often
spread throughout the body long
before the person even knows they
have the disease.
Smoker’s lungs
Secretory Epithelia
• Goblet cells
Mucus
Nucleus
Basal lamina
Golgi
apparatus
Goblet cells secrete mucus
into the lumen of hollow organs
such as the intestine.
Figure 3-27
Secretory Epithelia
Epithelium
• Development of
endocrine and
exocrine glands
from epithelium
Connective
tissue
Exocrine
Endocrine
Duct
Connecting
cells disappear
Exocrine
secretory cells
Endocrine
secretory cells
Blood vessel
Figure 3-28