Cell Structure and Function
I.
Introductory
a. Physiology = The study of biological function.... how the organism as a whole
accomplishes particular tasks essential for life
b. Organization of the Body
i. Cells, Tissues, Organs, Systems
ii. 4 Primary Tissues
1. Muscle Tissue
a. Skeletal
i. Voluntary
ii. Striated
iii. Myofibers
iv. graded contraction
v. tendons to bone
b. cardiac
i. involuntary
ii. striated
iii. intercalated disks
iv. whole heart contractions
c. smooth
i. involuntary
ii. no striations
iii. whole contraction
iv. digestive tract, lungs, blood vessels,
reproductive tissues
2. Nervous Tissue
a. Know the general schematic of a neuron (including some
or cell body, axon, dendrite, Node of Ranvier – Chapter
4 is a good place for this, particularly Fig. 4-11).
b. Functional unit = neuron
c. Functions in
i. muscle contraction
ii. gland secretion
d. Glia are the supportive, non-conductive cells that
surround the neuron.
3. Epithelial Tissue
a. Types are classified according to cellular shape
i. squamous – cheeks, capillaries, air sacs in lung
ii. cuboidal – reproductive tissues, kidney,
pancreas
iii. columnar – digestive
iv. ciliated columnar – uterine tubules, respiratory
cilia, transportive roles.
b. 2 major functions
i. membranes
1. keratinized or noncornified
2. junctional complexes (closely packed)
3. basement membranes (attached to
specialized polysaccaride/protein layer)
ii. glands - 2 types
1. exocrine (outside)
a. duct
b. secrete chemicals to outside
II.
2. endocrine (within)
a. ductless
b. secrete chemicals, such as
hormones, into the bloodstream
4. Connective Tissue - 4 types
a. connective tissue proper
i. loose = dermis of skin, collagen fibers. Space for
nerves, blood vessels, etc.
ii. dense = packed collagen
1. irregular = meshwork
2. regular = parallel fibers (i.e., tendons &
ligaments)
b. cartilage
i. chondrocytes (gristle)
ii. precursor to bone
c. bone - Haversian System
i. be familiar with terms such as osteoblast,
osteoclast, lacuna, lamellae, canaliculi, osteon
unit. See the book for more information,
including p. 703 and Fig. 19-20.
d. Blood
i. plasma - 46-50% of blood is plasma.
ii. interstitial fluid
iii. extracellular fluid (ECF)
iv. intracellular fluid (ICF)
Typical Organization of the cell
a. Structure and Function of the Primary Organelles
i. membrane – form, controls passage, capacitor
ii. cytoplasm – matrix for chemical reactions
iii. ER – transports materials, attaches ribosomes
iv. ribosomes – made of protein/RNA, synthesizes proteins
v. Golgi apparatus – synthesizes carbohydrates, secrets lipids,
glycoproteins.
vi. Mitochondria – synthesizes ATP, energy house
vii. Lysosomes – contains hydrolytic enzymes, garbage disposal, foreign &
domestic
viii. Nucleolus – helps with cell division (mitosis/meiosis), forms ribosomes
ix. Vesicles – storage and excretion/secretion
x. Vaults – octagonal protein, function unclear at this time but may be
involved in either mRNA transport or ribosome transport
xi. Peroxisomes – detoxifies cellular waste products (contains most of the
cell’s catalase), oxidative enzymes.
b. Important Cell Components for the Physiologist
i. The Cell Membrane (Next Unit!)
1. We will study the fluid mosaic model of the phospholipid bilayer
next week, but let’s consider the reasons a cell requires a
membrane:
a. Need selectivity barrier
b. Compartmentalization and specialization of function
c. 100X the volume passes through the cell every second
without any changes in the cell’s size; therefore there is
great specificity of what is allowed to permeate the
barrier and what is denied passage.
2. what is the membrane composed of?
a. “proteins in a sea of fat”
b. body is 84% water; must be composed of a non-water
soluble material therefore lipids
c. remember your general chemistry – like dissolved like,
so polar would dissolve polar.
3. transport and selectivity of passage is thought to be primarily due
to the type and arrangement of proteins present in the lipid.
ii. Cytosol and Cytoskeleton
1. up until the last 10 years, the cytosol/cytoskeleton were thought of
as a homogeneous matrix without an undefined function. Due to
freeze fracture, electron microscopy and fluorescence
techniques, we now know otherwise.
2. 3 Major Cytosolic Activities
a. enzyme regulation for intermediary metabolism
(synthesis, breakdown of simple sugars, fatty acids and
amino acids)
b. ribosomal protein synthesis
c. storage of fat, carbohydrates, and secretory vesicles.
3. Cytoskeleton creates a latticework using specialized proteins:
a. microtubules – transport of vesicles down the axon to be
used in nerve excitation
b. microfilaments – contractile systems such as muscle or
for mechanical stiffening support (as in specialized
sensory organs such as the ear)
c. intermediate filaments – tough durable fibers to provide
support in regions mechanically stretched as in the heart
(in between the size of # 1& 2)
d. microtrabecular lattice – acts to suspend the organelles
and traps free ribosomes in clusters at junctions of the
lattice.
iii. Mitochondria
1. should review for yourself !
a. glycolysis
b. pyruvate dehydrogenase complex
c. TCA/krebs cycle
d. Electron transport chain
2. know the amount of ATP produced under anaerobic vs. aerobic
metabolism
3. Cellular Activities That Require ATP
a. Synthesis – must maintaine protein synthesis for
secretion and growth
b. Membrane Transport – must transport molecules, ions,
and metabolites across membranes at energetically high
cost (the Na/K ATPase pump uses 25% of your total
body ATP!)
c. Mechanical Work – must use energy to contract skeletal,
smooth, cardiac muscle tissues
4. Red blood cells (RBC) contain no mitochondria – how do they
obtain ATP? Strictly glycolysis therefore only 2 net ATP.
5. Chemiosmotic hypothesis: cellular basis for the generation of ATP
molecules.
a. Hydrogen carriers such as NADH release H at the inner
mitochondrial membrane (IMM)
b. High energy electrons are extracted from the H and are
donated to electron acceptors which pass the electrons
from high to low energy down the chain.
c.
Energy released at three sites along the transport chain
permits more H+ to be transported up the hydrogen
gradient (therefore requires energy) and
H+_accumulates in the intermembrane space.
d. H+ flows back down its concentration gradient through
specialized protein channels = ATP synthase (ATPase).
This enzyme becomes activated and joins ADP + Pi 
ATP
6. Electron Transport Chain – See figure 2-13