The Cell Theory
Chapter 2
The Cell
 All living things are made of cells.
 Cells are the smallest living unit of life.
 Each cell performs the necessary
functions to sustain life.
 Cells can replicate themselves. Cancer
occurs when cells replicate haphazzardly.
 Cellular function is carried out by
organelles.
 Cellular reactions are mediated
(controlled) by ENZYMES.
 Enzymes speed up chemical reactions.
 All the chemical reactions in the body
make up its METABOLISM.
 There are 10 organelles that you are
responsible for.
Plasma Membrane
 Outer covering of the cell.
 Also called the PLASMALEMMA.
 Separates the intracellular (inside) fluid
and the extracellular (outside) fluid.
 Double layer of lipids (fat) with protein
molecules between the layers.
 Polar Head (like water)
 Non-polar tails (do not like water)
 Proteins within the membrane. They give
support to the membrane and prevent it
from collapsing.
 Carbohydrates are attached to the
integral proteins. These form the
GLYCOCALYX.
 The glycocalyx is a sticky coat that allows
the cell to bind to other cells.
 The glycocalyx also serves as a marker.
i.e.: certain antibiotics recognize the
glycocalyx and attach to the cell.
Functions of the Plasma
Membrane
 Allows entry into the cell (Endocytosis)
Phagocytosis – cell eating
Pinocytosis – cell drinking
Receptor-Mediated - hormones
 Allows movement out of cells
(Exocytosis)
Cytoplasm
 Cytosol is a gel like substance which
holds all the internal cellular organelles.
 Contains ions, water, and enzymes.
THE ORGANELLES
 Perform all the cellular functions.
 “Little Organs”
MITOCHONDRIA
Power plant of the
cell
Produces energy
RIBOSOME
 2 parts that make proteins.
Ribosome
RNA
ENDOPLASMIC
RETICULUM
 Subway system of the cell.
 Network of membrane-walled tubes that
twist through the cytoplasm.
 ROUGH E.R. – have ribosomes
attached.
 SMOOTH E.R. – do not have ribosomes
attached.
GOLGI APPARATUS
 Stacks of disk shaped membranes.
Sort
Package
Process
proteins made in the ER
LYSOSOMES
 Sacs containing digestive enzymes that
can break down almost all types of
biological materials.
PEROXISOMES
 Contain oxidases (use oxygen to
neutralize aggressive compounds known
as free radicals).
 Free radicals can damage cellular
proteins, membranes, and DNA if left to
accumulate.
CYTOSKELETON
 System of complex rods that run
throughout the cytoplasm.
 Microtubules
 Microfilaments
CENTROSOME
 Contains a matrix and an inner pair of
centrioles which are important in cellular
division.
NUCLEUS
Membrane bound organelle which is the
control center for all cellular activity..
Contains DNA – produce instructions for
protein synthesis.
Contain chromosomes
Produce ribsomes in the nucleolus
Specialized Connections Between Cells Desmosome
1Microvilli
2 - Zonula
occludens
3 - Zonula
adherens
4Desmosome
5 - Terminal
Web
6Interdigitation
Related Clinical Terms
 NECROSIS – cellular death due to
disease or injury.
 HYPERTROPHY – increase in size.
i.e. Muscle cells become hypertrophic
in response to exercise.
Rough
Endoplasmic
reticulum
Cell
membrane
Golgi
apparatus
nucleus
Nuclear
membrane
nucleolus
mitochondria
Smooth
Endoplasmic
reticulum
TISSUES
Chapter Four
OBJECTIVES for Tissues
 Be able to list the four basic tissue types
and give examples of each.
 Describe the functions of each tissue
type.
 Describe the cellular components of each
tissue type.
 Describe and identify the morphology of
epithelial tissue types.
Tissues
 Cells do not operate independently.
 Related cells work and operate together
in organized groups.
The bottom line:
Tissues are clubs of cellular organization.
Four Types of Tissues
 1. Epithelial Tissue
 2. Connective Tissue
 3. Muscle Tissue
 4. Nervous Tissue
EPITHELIAL TISSUE
Covers the body surface
or
Lines a body cavity
Epithelial Tissue
 Occurs at the interface of two different
environments.
i.e. The epidermis is between the
inside and the outside of the body.
 Protects the body by detecting harmful
stimuli.
i.e. Receptors for pain are found within
the skin.
 Secretion
release of molecules from the cell
 Absorption
bringing small molecules into the cell.
 Ion transport – moves ions (charged
molecules) across a membrane.
 The epithelium filters fluids that cross the
barrier.
Characteristics of
Epithelial Tissue
1. Cellularity – composed almost entirely of
cells.
2. Specialized Contacts – connects adjacent
cells.

gap junctions, tight junctions, desmosomes
3. Polarity – under surface called the
“basement membrane”.
4. Avascular – lacks blood vessels. Receives
nutrients through the underlying connective
tissue
5. Regeneration – replaces lost/dead
cells quickly.
Shapes of Epithelial
Tissue
 Simple Epithelium – one layer
 Stratified Epithelium – more than one
layer
 Squamous – cells are wider than tall
 Cuboidal – cells are just about as tall as
wide
 Columnar – cells are taller than wide.
An Illustrated View of Epithelial Types
Simple Cuboidal Epithelium
Simple Columnar Epithelium
Pseudostratified Ciliated Columnar Epithelium
Pseudostratified ciliated columnar epithelium with pale goblet
cells. The different levels of nuclei are clearer here. Again, notic
the wavy-looking cilia
Stratified squamous
epithelium with
beginning surface
cornification. This
section is from thin skin,
which has a dry surface
covered with dead cells.
Notice how flat the
surface cells are and
how dark and pyknotic
(degenerative) their
nuclei have become.
Again, notice the distinct
row of basal cells.
CONNECTIVE TISSUE
 Types of connective tissue
Fat
Cartilage
Ligaments and Tendons
Bone
Blood
Collagen
Functions of Connective
Tissue
 1. Support and bind other tissues. (tendons,
ligaments)
 2. Hold body fluids (ground substance).
 3. Defend against infection
- mast cells
- macrophages
- plasma cells
- neutrophils
 4. Store nutrients as fat.
Mesenchyme -embryonic c.t.
with multipotential
cells.
A stretched preparation
of areolar
connective
tissue. The pink
fibers of different
thicknesses are
collagenous (or white)
fibers. The dark, thin,
more tortuous fibers are
elastic (or yellow) fibers.
Most of the nuclei
belong to fibroblasts.
Fat cells -- note
nucleus and rim of
cytoplasm pushed
to one side by the
accumulation of
fat. The lipid itself
has been
dissolved out in
fixation. In the
center of the
picture, in the
space bounded by
the four large fat
cells, there is a
small, round crosscut of a capillary
with a dark,
shrunken red
blood cell inside.
Hyaline cartilage from the trachea
BLOOD - Neutrophil - Erythrocytes
1 – Erythrocyte
2 - Neutrophil
Muscle Tissue
 Brings about body movement.
 Moves by shortening.
 Three Types:
1. skeletal – pulls on long bones. Striated.
2. cardiac – only in the heart.
3. smooth – no visible striations. Found in
walls of hollow visceral organs such as
digestive system, urinary organs, blood
vessels, and uterus. Mostly involuntary.
1 -A Band
2 - Z Line
3 - Intercalated disks
Skeletal Muscle Fibers
1 - Multinucleated skeletal muscle fibers
Smooth Muscle Tissue
1 – Smooth
muscle fibers
2 – Artery
endothelium
3- Artery Lumen
Nerve Tissue
 Uses electrical impulses to transport
information.
 Can Regenerate
Neurons
1 - Glial cells 2 - Neurons
Identify the
Following:
Epidermis
Dermis
Epithelial
Tissue
Hair follicle
Subcutaneous fat
CT
Pore
Arrector Pilae Muscle
Nerve Endings
ALL FOUR TISSUE
TYPES ARE USUALLY
FOUND TOGETHER