Transcript Anatomy and Physiology - Effingham County Schools

Anatomy and Physiology
Cell Structure
Structure
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Cell (plasma) membrane - The
selectively permeable outer boundary
of a cell consisting of a phospholipids
bilayer embedded with proteins.
Nucleus - Cellular organelle that is
enclosed by a double layer, porous
membrane, and contains DNA.
Cytoplasm - The entire contents inside
of a cell excluding the cell membrane
and nucleus. Cytosol - liquid portion
Cell Structure
• Shape differs according to cell function.
Cell Membrane
• Encloses the cell.
• Internal cell
membrane forms
membrane of nucleus
and organelles.
• Composed mainly of
phospholipids and
protein.
• Described as being a
fluid mosaic model.
• Lipid layer
Lipid Layer
• Heads are made of
phosphate groups
and are considered
hydrophilic = water
loving.
• Tails are made of
lipid molecules and
are considered
hydrophobic = water
fearing.
Lipid Layer
• Proteins are
embedded on and in
the lipid layer.
• Some are attached
to the surface,
inner layer, and all
the way through.
Function of the Cell Membrane
• Receives information from other cells.
• Transportation of molecules into and
out of cells.
• Recognizes cells as belonging to a
particular person.
– Tissue typing for transplants.
Organelles
• Endoplasmic Reticulum
– Network of tunnels
throughout the
cytoplasm of the cell.
– Miniature circulatory
system for the cell.
• 2 Types
– Smooth (SER)
• Synthesizes lipids
– Rough (RER) - has
ribosomes
• Synthesizes proteins
Organelles
• Ribosomes
– Function to make
proteins for the
cell.
• 2 Locations
– Free floating in the
cytoplasm.
– Attached to
endoplasmic
reticulum.
Organelles
• Golgi Apparatus
– AKA Golgi Body or
Golgi Complex
– Consists of tiny sacs
stacked on top of
one another.
– Synthesizes large
carbohydrates and
combines with
proteins=glycoprotein
– Transport vesicles
form, carrying
substances to
different parts of
the cell.
Organelles
• Mitochondria
– “Powerhouse of the
cell”
– Consists of a double
membrane wall.
– Inner membrane
folds into
extentions-cristae
– This is the site of
cellular respiration
for production of
ATP - cellular
energy molecule.
Organelles
• Mitochondria
continued…
• The more work a
cell completes, the
more mitochondria.
– Ex. Muscle cells
Organelles
• Lysosomes
– “Suicide bags or
garbage disposals”
– Contain enzymes
that break down cell
parts.
– Destroy bacteria
when it enters the
body.
• White blood cells
engulf bacteria and
lysosomes destroy
them.
Organelles
• Peroxisomes
– Located in all
human cells but
most abundant in
liver cells.
– Among many
functions, it
helps in the
detoxification of
alcohol.
Organelles
• Centrioles
– Appear as two
dots located near
the nucleus.
– Forms spindle
fibers during cell
division
(mitosis/meiosis).
Organelles
• Cell Fibers
– Made of proteins
• Form a 3-D lattice
which helps support
the cell.
(cytoskeleton)
– Serves as the
muscle of the cell.
• Ex.- microfilaments
and microtubules.
Organelles
• Nucleus
– Largest cell
structure.
– Contains DNA.
– The center of
the nucleus
contains the
nucleolus.
• Nucleolus
manufactures
ribosomes.
Inclusions
• Lifeless chemicals
• In a cell temporarily
• Store
– Nutrients - glycogen and lipids
– Pigments - ex. Melanin
• http://www.wiley.com/legacy/college/boyer
/0470003790/animations/cell_structure/c
ell_structure.htm