Cell Anatomy
Membrane Physiology
Passive and Active Transport
DNA replication
Mitosis
Protein Synthesis
Cells and Tissues
Chapter 3
Cell Diversity
Structure – Function Relationships!
Cells that connect body parts
• Fibroblast – This cell secretes cable like fibers,
it has abundant rough ER and a large golgi
apparatus to make and secrete the protein
building blocks of these fibers.
Fibroblast
Cells that cover and line body
organs:
• Epithelial cell – They have a hexagonal shape.
This shape allows them to pack together in
sheets. They also have abundant intermediate
filaments which resist tearing
Epithelial Cells
Cells that move organs and
body parts
• Skeletal and smooth muscle cells are
elongated and filled with contractile filaments
so they can shorten forcefully and move bones
or change the size of internal organs
Smooth/Skeletal Muscle
Cells that store nutrients
• Fat cells have a large spherical shape due to
the lipid droplet in its cytoplasm
Fat Cells
Cells that fight disease
• Macrophage have long pseudopods which it
can extend to reach through tissue to
infection sites. It also contains many
lysosomes to digest the infectious
microorganisms it takes up.
macrophage
Cells that gather information
and control body function
• Nerve Cells have long projections that receive
and transmit messages.
Nerve Cell
Cells of reproduction
• Oocytes contain many copies of all organelles
for distribution to the daughter cells that arise
when the cell divides.
• Sperm are long and streamlined with a
flagellum so they are built for swimming
sperm/oocyte
Tissues
• As a fertilized eggs divides the millions of cells
that result become specialized for specific
functions, creating a division of labor in the
body.
• Groups of cells that are similar in their
structure and function are called tissues.
Tissues
Epithelial Tissue
Connective Tissue
Muscle Tissue
Nervous TIssue
EPITHELIAL TISSUE
• Makes up the lining, covering and glandular
tissue of the body.
• Primary functions include protection,
absorption, filtration and secretion.
Special Characteristics of
Epithelium
• Cells fit closely together and are bound by cell junctions
• They have one free edge exposed to either the exterior
of the body or the body cavity. (apical surface)
• The lower surface rests on a basement membrane- a
structure-less material secreted by the cells.
• The cells do not have their own blood supply. They
depend on diffusion from connective tissue capillaries.
Classification of Epithelium
1. Simple Epithelium
one layer of cells – usual functions include
absorption, secretion and filtration
a. Simple Squamous Epithelium – usually
forms membranes where filtration or rapid
exchange of substances occurs (air sacs in the
lungs – capillaries)
Classification of Epithelium
1. Simple Epithelium
one layer of cells – usual functions include
absorption, secretion and filtration
b. Simple Cuboidal Epithelium – common
in glands and ducts
Classification of Epithelium
1. Simple Epithelium
one layer of cells – usual functions include
absorption, secretion and filtration
c. Simple Columnar Epithelium – houses
goblet cells. Lines the entire length of the
digestive tract.
Classification of Epithelium
2. Stratified Epithelium
two or more layers of cells – primary function is
to protect
a. Stratified Squamous Epithelium – the
most common type, usually several layers of
cells. The cells at the free edge are squamous,
whereas those close to the basement
membrane are cuboidal or columnar. Found in
areas that receive a good deal of abuse or
friction.
Classification of Epithelium
2. Stratified Epithelium
two or more layers of cells – primary function is
to protect
b. Stratified Cuboidal/ Stratified
Columnar – both fairly rare in the body, mainly
found in the ducts of large glands.
Classification of Epithelium
2. Stratified Epithelium
two or more layers of cells – primary function is
to protect
c. Transitional Epithelium – highly
modified stratified squamous epithelium that
forms the lining of the urinary system organs.
They have the ability to slide past one another
and change shape allowing the organs to
stretch.
Classification of Epithelium
2. Stratified Epithelium
two or more layers of cells – primary function is to
protect
d. Glandular Epithelium - makes up glands.
Glands can make and secrete products.
The products are called secretions and contain
protein in a aqueous solution.
Endocrine glands secrete directly into the blood stream
(hormones)
Exocrine glands secrete into ducts which go to the epithelial
surface (sweat)
CONNECTIVE TISSUE
• It is the most abundant and widely distributed
tissue in the body.
• It connects body parts.
Common Characteristics of
Connective Tissue
• Most commonly it is well vascularized,
however some types have very little blood
supply.
• Although connective tissues can be made up
of many different cell types, they all have
varying amounts of a non living substance
called the extracellular matrix.
Extracellular Matrix
• Cells that make up connective tissue make
extracellular matrix and secrete it to their
exterior. It has two man parts
• 1. a ground substance (mainly water and some
adhesion proteins)
• 2. large charged polysaccharide molecules
(more polysaccharides leads to harder
consistency) with different amounts and types
of fibers deposited in it.
Extracellular Matrix
• Because you can have such a broad variety in
the number of cells that the matrix is
surrounding, and the rigidity of the matrix
itself, connective tissue comes in a wide range
structures
• Mostly cells with a soft matrix
• Very few cells with large amounts of hard
matrix
Extracellular Matrix
Types of Connective Tissue
All composed of cells surrounded by a matrix.
The major difference reflect the number and
types of fibers in the matrix
Bone
Cartilage
Dense Connective
Loose Connective
Blood
Bone
• Bone cells sitting in cavities called lacunae.
• Surrounded by a very hard matrix that
contains Ca salts and a large amount of
collagen fibers.
Cartilage
less hard and more flexible than bone
1. Hyaline Cartilage – abundant collagen fibers
and a rubbery matrix – between the ribs and
breastbone. (most widespread)
2. Fibrocartilage – disks between the vertebrae
3. Elastic Cartilage - ears
Dense Connective Tissue
A matrix of mainly collagen fibers, with rows of
fibroblasts crowded in between forming strong
ropelike structures
• Tendons- skeletal muscle to bone
• Ligaments – connect bones to bones at the
joints
• Lower layers of the skin
Loose Connective Tissue
Softer tissues with more cells and fewer fibers
• Areolar Tissue- pliable tissue that cushions and
protects the body organs. “Packs” organs
together in the proper positions with a fluid,
loose network of fibers
• Adipose Tissue – forms the subcutaneous tissue
beneath the skin, insulates, and stores fuel.
• Reticular Tissue forms the stroma in lymphnoid
organs
Blood
• Vascular Tissue – blood cells surrounded by a
fluid matrix called plasma.
• Transport vehicle for the cardiovascular
system.
MUSCLE TISSUE
• Tissues that are highly specialized to contract,
or shorten
• 3 types
Skeletal Muscle
• Skeletal muscle tissue is packaged by
connective tissue sheets into organs called
skeletal muscles.
• The cells are long, cylindrical, and
multinucleate. They have stripes called
striations.
• They are involved in voluntary movement
Cardiac Muscle
• Only found in the heart
• The tissue has striations, but individual cells
are branching and each only have one
nucleus.
• The branching cells fit together at intercalated
disks that contain gap junctions. These
junctions allow ions to pass freely from cell to
cell resulting in rapid conduction of electrical
impulse across the heart.
Gap Junctions
Smooth Muscle
• This muscle has no striations. Cells have one
nucleus and are pointed at the ends.
• It is found in the walls of hollow organs,
stomach, bladder, blood vessels, uterus…
• It contracts at a slower rate in order to move
substances through the organ along a specific
pathway.
NERVOUS TISSUE
• The cells are neurons whose major functions
are irritability and conductivity.
• Along with supporting cells to insulate,
support and protect the neurons, nervous
tissue makes up the brain, spinal cord, and
nerves.
Tissue Injuries and Repair
• The restoration of homeostasis after a tissue
has been injured involves two related
processes…. Inflammation and Regeneration
Inflammation
• Immediately after an injury, the area is
isolated while damaged cells, tissue
components, and any dangerous
microorganisms are cleaned up.
• Familiar symptoms of inflammation include,
swelling, redness, warmth and pain.
Regeneration
• Second, damaged tissues are replaced or
repaired.
The two phases overlap, isolation establishes a
framework that guides the cells responsible for
reconstruction, and repairs are underway before
cleanup operations have ended.
Impact, abrasion, distortion,
infection, chemical irritation…..
• Certain stimuli kill cells, damage fibers, or
injures the tissue in some way. When this
happens, the chemical composition of
interstitial fluid is altered. The damaged cells
release prostaglandins, proteins, and K+ ions
• Necrosis occurs due to lysosomal enzymes.
Inflammation
• Tissue changes trigger the connective tissue to
stimulate mast cells which in turn release a
variety of chemicals
Inflammation
• Tissue changes trigger the connective tissue to
stimulate mast cells which in turn release a
variety of chemicals
• This stimulates changes in circulation, blood
vessel dilation (redness and heat)
Inflammation
• Tissue changes trigger the connective tissue to
stimulate mast cells which in turn release a
variety of chemicals
• This stimulates changes in circulation, blood
vessel dilation (redness and heat)
• Abnormal tissue conditions and mast cell
chemicals stimulate sensory nerve endings
(pain)
Inflammation
• Tissue changes trigger the connective tissue to
stimulate mast cells which in turn release a
variety of chemicals
• This stimulates changes in circulation, blood
vessel dilation (redness and heat)
• Abnormal tissue conditions and mast cell
chemicals stimulate sensory nerve endings (pain)
• The epithelial cells in capillaries become more
permeable, allowing plasma and blood proteins
diffuse into the injured area. (swelling)
• With the increase in blood flow you have an
increase in the supply of oxygen and nutrients
to the site, and an increase in the removal of
wastes.
• Phagocytic white blood cells assist in defense
and cleanup.
• Both debris and bacteria are engulfed and
removed.
Regeneration
• With cleanup well underway, fibroblasts move
into the necrotic area and lay down a network
of collagen fibers that stabilizes the injury site.