Cells (Cytology) – Ch. 2 – Complete Version
Human Anatomy lecture
I. Introduction
A. The body has 3 major structural components
 cells
 intercellular material – fibers and crystals
 body fluids
 extracellular fluid (ECF)
- interstitial fluid – between cells
- plasma – within blood vessels
- lymph – within lymph vessels
 intracellular fluid (ICF) – cytosol
B. Cells are the unit of structure and function
1. responsible for formation of intercellular materials and fluids
2. wide range of sizes
- RBC  8m (micrometer = 1/millionth meter)
- ovum  140
- neuron > 1meter long
3. wide range of shapes  Know Fig. 2.3
squamous
cuboidal
columnar
polygonal
stellate
spheroid
discoid
fusiform
fibrous
4. more than 100 trillion in the body and more than 200 types
C. Even at cellular level, structure is related to function (Remember Rule #1?)
Ex.: skeletal muscle cells  single long cell contracts more efficiently than
multiple shorter cells
D. Cells have 4 major components
1. plasma membrane
2. cytosol
3. organelles
= cytoplasm (except nucleus)
4. inclusions
II. Plasma membrane  Fig. 2.6
A. Structure described by fluid-mosaic model – “protein icebergs floating in a
phospholipid sea”
B. Plasma membrane is constantly changing: segments added/ removed
proteins added/ removed
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C. Functions
1. defines cell boundary
2. selective permeability – controls passage of materials in/out of cell
D. Extensions aid in absorption, movement, & sensory processes  Fig. 2.15
1. microvilli
2. cilia
3. flagella
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III. Organelles – Fig. 2.5 & 2.17
Match the following descriptions with the appropriate organelle.
__________ single, elongated projection of plasma membrane containing 9 pairs of
microtubules; capable of moving entire cell
__________ membranous sac containing digestive enzymes that break down microbes &
molecules
__________ surrounded by double membrane; contains genes and controls cellular activities
__________ includes three types of protein filaments (microtubules, microfilaments, and
intermediate filaments) that give the cell shape and enable coordinated
movements of organelles
__________ non-membranous site of protein synthesis; may be free in cytosol or attached to
endoplasmic reticulum
__________ consists of pericentriolar area and centriole pair; organizes microtubules
__________ double-membrane sac that is the site of most ATP production
__________ numerous, short motile projections of plasma membrane capable of moving
substances along surface of cell
__________ membrane-bounded channel network that provides surface area for many cellular
chemical reactions; synthesizes lipids and detoxifies certain molecules
__________
membranous sac containing enzymes that use oxygen to oxidize potentially toxic
substances
__________ stack of disc-shaped membrane-enclosed cisterns; packages proteins and lipids for
export and forms lysosomes
__________
dark-stained intranuclear mass composed of protein & RNA; site of ribosome
assembly
__________ short, non-motile extensions of plasma membrane that increase the surface are for
absorption/secretion
nucleus
endoplasmic reticulum(ER)
lysosome
mitochondria
microvilli
ribosome
Golgi complex
peroxisome
cytoskeleton
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cilia
nucleolus
centrosome
flagellum
IV. Inclusions
A. Not membrane-bound, nor defined shape, nor permanent
B. Clumps of chemical substances produced by cells for storage or export
Ex: fat, glycogen, or melanin
or
C. Foreign bodies (dust, viruses, bacteria)
V. Cytosol (intracellular fluid - ICF)
A. Water: 75-90%
B. Proteins: 15-20%
C. Carbohydrates, lipids, and ions
RESULT: A clear gel-like state of variable solidity (Jell-O is only 2% protein)
D. Many cellular metabolic reactions occur here
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