NUR 101 Body Structure and
Function
MODULE C: CELLS AND TISSUES
CELLS
CELLS
A.
vary considerably in
size
B.
are microscopic
C.
differ notably in shape
COMPONENTS OF A CELL
CYTOPLASMA
A.
B.
Cytoplasm which contains
specialized organelles and is
surrounded by a plasma
membrane
Organization of cytoplasmic
substances important to life
COMPONENTS OF A CELL
PLASMA MEMBRANE
1. Forms outer boundary of cell
2. Thin, two-layered membrane of
phospholipids containing proteins
3. Is selectively permeable
CYTOPLASM ORGANELLES
Ribosomes
Endoplasmic reticulum (ER)
Golgi apparatus
Mitochondria
Lysosomes
Centrioles
Cilia
Flagella
RIBOSOMES
1. Are very tiny particles found through out
the cell
2. Some are attached to a network of
membranous canals called
endoplasmic reticulum (ER) ,some are
free in the cytoplasm
3. Make enzymes and other protein
compounds -“protein factories”
ENDOPLASMIC RETICULUM (ER):
1. Form a network of connecting sacs and
canals from the nucleus almost to the plasma
membrane.
2. Carry proteins and other substances through
the cytoplasm from one area to another
3. Are both rough and smooth. The rough ER
receives and transports newly made proteins
and smooth ER makes new membrane
GOLGI APPARATUS
1. Tiny flattened sacs stacked near the nucleus.
2. Collect vesicles filled with proteins and other
compounds from the smooth ER
3. Chemically processes the molecules and
packages the material in vesicles that move
from the golgi apparatus to the plasma
membrane and opens to the outside of the
cell “chemical processing and packaging
center”
MITOCHONDRIA
1. Made of two membranous sacs one inside
the other
2. Complex, energy releasing chemical
reactions occur continuously
3. Supply most of the power for cellular work
“power plants”
4. Enzymes within the walls use oxygen to
break down glucose and other nutrients to
release energy required for cellular work
LYSOSOMES
1. Are membranous walled organelles that in
the active state look like small sacs.
2. Contain chemicals (enzymes) that digest food
compounds “ digestive bags”
3. Also digest other substances such as
microbes which protects the cell
4. Can kill the cell if the digesting enzymes
escape from the lysosomes sac into the cell
“suicide bags”
CENTRIOLES
1. Are two rod-shaped structures
2. Lie at right angles to each other
near the nucleus
3. Participate in cell reproduction
CILIA
1. Fine almost hair like extensions on
the exposed or free surfaces of
some cells
2. Are capable of moving in unison in
a wavelike fashion over the surface
of a cell.
Flagella
1. Are single projections extending
from cell surfaces
2. Are much larger than cilia
3. “Tails” of sperm cells only example
of flagella in humans
STRUCTURAL COMPONENTS OF
A CELL
 NUCLEUS
1. Controls cell because it contains the
genetic code- instructions for making
proteins, which in turn determine cell
structure and function
2. Component structures include nuclear
envelop, nucleoplasm, nucleous, and
chromatin granules
3. Chromosomes contain DNA
Movement of Substances
Through Cell Membranes
 PASSIVE TRANSPORT
1. Diffusion
Osmosis
Dialysis
2. Filtration
ACTIVE TRANSPORT
1. Ion pumps
2. Phagocytosis and pinocytosis
Passive Transport Processes
 DIFFUSION
1. is the process by which substances
scatter evenly throughout an available
space without utilizing energy.
2. movement is from high concentration
to low concentration
3. specialized examples diffusion :
osmosis and dialysis
Passive Transport Processes
FILTRATION
1. is the movement of water and solutes
through a membrane caused by
hydrostatic pressure
2. move water and solutes from an area
with higher hydrostatic pressure to an
area with lower hydrostatic pressure
3. is the process responsible for urine
formation
Active Transport Processes
 ION PUMP
1. is a protein structure in the cell
membrane called a carrier
2. uses energy from ATP (adenosine
triphosphate) to move ions across cell
membranes against the concentration
gradient (lower concentration to higher
concentration)
3. is specific to particular ions
Active Transport Processes
 PHAGOCYTOSIS – is the movement of cells
or other large particles into the cell by trapping
it in a section of plasma membrane. The
material then fuses with lysosomes and is
destroyed
 PINOCYTOSIS- is the movement of fluid and
dissolved molecules into the cell by trapping
them in a section of plasma membrane that
pinches off inside the cell
Movement of Substances
Through Cell Membranes
 TONICITY
 Isotonic is a solution containing an equal
level of NACL as a living red blood cell
 Hypotonic is a solution containing a lower
level of NACL than is found in a living red
blood cell
 Hypertonic is a solution containing a higher
level of NACL than is found in a living red
blood cell
DNA STRUCTURE
1. Large molecule shaped like a spiral staircase
2. Sugar (deoxyribose) and phosphate units
comprise the sides of the molecule
3. base pairs (adenine-thymine or guaninecytosine) compose “steps”
4. Gene is a specific sequence of base pairs
within a DNA molecules
5. Genes dictate formation of enzymes and
other proteins by ribosomes thereby indirectly
determining a cell’s structure and function,
genes are heredity determinants
GENETIC CODE
 The coded or stored information in each
gene controls protein and enzyme
production, enzymes facilitate cellular
chemical reactions, and cellular chemical
reactions determine cell structure and
function and thereby heredity.
 DNA with its genetic code is contained in
the nucleus of the cell.
Protein synthesis
 The process of transferring genetic information from
the nucleus into the cytoplasm requires the completion
of two steps:
 Transcription is the formation of a messenger RNA
(mRNA) from a particular DNA gene sequence. mRNA
then passes from the nucleus to the cytoplasm
 Translation is the synthesis of protein by ribosomes
utilizing the information contained in the mRNA
molecule to direct choice and sequence of amino acids
to form a protein strand and molecule
CELL REPRODUCTION
 DNA REPLICATION is a process by which
each half of a DNA molecule becomes a whole
molecule identical to the original DNA
molecule; precedes mitosis
 MITOSIS Is a process in cell division that
distributes identical chromosomes (DNA
molecules) to each new cell formed when the
original cell divides. It enables cells to
reproduce their own kind, Makes heredity
possible
CELL REPRODUCTION
 PHASES OF CELL DIVISION (MITOSIS)
Prophase
Metaphase
Anaphase
Telophase
PROPHASE : First Phase
1. Chromatin granules become organized
2. Chromosomes (pair of linked
chromatids) appear
3. Centrioles move away from the nucleus
4. Nuclear envelope disappears, freeing
genetic material
5. Spindle fibers appear
METAPHASE : Second Phase
1. Chromosomes align across center of
cell
2. Spindle fibers attach themselves to
each chromatid
ANAPHASE : Third Phase
1. Centromeres break apart
2. Separated chromatids now called
chromosomes
3. Chromosomes are pulled to opposite
ends of cell
4. Cleavage furrow develops at end of
anaphase
TELOPHASE : Fourth Phase
1. Completed cell division
2. Two Nuclei and nuclear envelopes
appear
3. Cytoplasm is divided (cytokinesis)
4. Two fully functional cells, each having
identical genetic characteristics are
formed
TYPES of TISSUE




EPITHELIAL
CONNECTIVE
MUSCLE
NERVOUS
EPITHELIAL TISSUE
Types of Epithelial Tissue
1. Simple squamous
2. Stratified squamous
3. Simple columnar
4. Stratified transitional
5. Pseudostratified
6. Simple cuboidal
CONNECTIVE TISSUE
Types of Connective Tissue
1. Areolar
2. Adipose
3. Dense fibrous
4. Bone
5. Cartilage
6. Blood
7. Hemopoietic
MUSCLE TISSUE
 There are three kinds of muscle tissue:
 Skeletal (striated voluntary) – Long threadlike
cells with multiple nuclei and striations
 Cardiac (striated involuntary) Branching
interconnected cylinders with faint striations
 Smooth (non- striated involuntary visceral)
threadlike cells with single nuclei and no
striations
NERVOUS TISSUE
1. Consists of two kinds of cells : Neurons the
functional or conducting units and Glia (
neuroglia) the connecting and supporting
cells
2. Is characterized by a cell body and two types
of processes: one axon which transmits a
nerve impulse away from cell body and one
or more dendrites which carry impulses
toward the cell body