Ch. 1 The Human Body: Orientation
Anatomy- form, structure of body parts and their relationship to one another
Gross- study of large body structures
Regional- all structures in particular region
Systemic- system by system
Surface- study of internal structures as they relate to overlying skin surface
Microscopic- structures too small to be seen with naked eye
Cytology- cells of body
Histology- study of tissues
Developmental- traces structural changes throughout lifespan
Embryology- subdivision of developmental anatomy, changes before birth
Pathological- changes caused by disease
Radiographic- internal structures as visualized by x-ray scans
Physiology- function, how the body works and carry out life-sustaining activities
Complementarity- structural characteristics contribute to function
Chemical level- atoms form molecules form organelles which are the basic components of cells
Cellular level- smallest unit of living things
Tissue level- groups of similar cells that have a common function
Organ level- extremely complex functions become possible
Organ system level- organs work together to accomplish common purpose
Organism- sum of total structural levels
1. Maintain boundaries- internal enviro remains distinct from external
2. Movement- muscular system activities, shortening of cells called contractility
3. Responsiveness- excitability, sensation of changes in enviro and response to them
4. Digestion- breakdown of foodstuffs for absorption into the blood
5. Metabolism- chemical reaction, break down into simpler building blocks (catabolism), synthesizing
more complex structures (anabolism), using nutrients and O2 to produce ATP for energy (cellular
respiration)
6. Excretion- removal of waste
7. Reproduction- cell division for growth/repair, producing offspring
8. Growth- increase in size of body part of organism
Survival needs
Nutrients- diet, carbs, vitamins, minerals, proteins, fats, major energy fuel
O2- chemical reactions that release energy are oxidative reactions
Water- 50-60% of body weight
Temperature- 37 degrees Celsius, if too high or low cell death occurs
Atmospheric pressure- force that air exerts on surface of body, breathing and gas exchange
Homeostasis- ability of body to maintain relatively stable internal conditions, indicates a dynamic state of
equilibrium/balance, relatively narrow limits
Receptor- sensor that monitors enviro and responds to stimuli (input/afferent pathway)
Control center- determines set point, level or range variable is to be maintained
Effector- control’s response to stimulus (output/efferent parthway), feedback to influence effect
Negative Feedback Mechanism- output shuts off original effect or reduces intensity, cause variable to change
in direction opposite to that of initial change returning to its ideal value
Ex) body temperature, blood glucose levels
Positive Feedback Mechanism- response enhances original stimulus so the response is accelerated, proceeds
in same direction as initial change causing further deviation (cascades)
Ex) birth, blood clotting
Anatomical Position- body erect with feet apart, palms forward and thumbs away from body
Directional Terms- explain where one body structure is in relation to another
Axial- head, neck, trunk
Appendicular- limbs
Planes
Sagittal- vertical plane dividing into left and right
Frontal- vertical plane dividing into anterior and posterior
Transverse- runs horizontally from right to left dividing into superior and inferior
Oblique- cuts diagonally between horizontal and vertical planes, seldom used
Body Cavities
Dorsal- protects fragile nervous system, divided into cranial and vertebral/spinal cavity
Ventral- anterior, larger, houses internal organs called the viscera
Thoracic- surrounded by ribs and muscles of chest
Pleural- enveloping each lung
Medial mediastinum- contains pericardial cavity enclosing heart and surrounds
esophagus and trachea
Abdominopelvic- by the diaphragm
Abdominal- contains stomach, intestines, spleen, liver
Pelvic- lies in bony pelvis, contains bladder, reproductive organs, rectum
Membranes
Parietal serosa lines cavity walls, folds in on itself to form visceral serosa, separated by serous fluid,
allows organs to slide without friction
Quadrants
RUQ
LUQ
RLQ
LLQ
Regions
Right hypochondriac
Epigastric
Left hypochondriac
Right lumbar
Umbilical
Left lumbar
Right iliac/inguinal
Hypogastric/pubic
Left iliac/inguinal
Other cavities- oral/digestive, nasal, orbital, middle ear, synovial
Ch. 3 Cells: The Living Units
Cell Theory- cell is the basic structural and functional unit of living organisms, activity of organism depends on
individual and combined activities of its cells, biochemical activities of cells are dictated by their shapes/forms,
cells can only arise from other cells
Cell Structure
Plasma membrane- outer boundary of cells, selectively permeable barrier, separates intracellular fluid within
cells and extracellular flid outside cells
Fluid mosaic model-thing structure, bilayer of lipids, proteins form a constantly changing mosaic
pattern
Phospholipids- polar hydrophilic head, nonpolar hydrophobic tail of fatty acid chains
Glycolipids- lipids attached sugar groups, account for 5% of total membrane lipids
Cholesterol- 20% of membrane, has polar and nonpolar region, wedges its hydrocarbon rings between
phospholipid tails which stabilizes the membrane
Integral Proteins- inserted into lipid bilayer, most are transmembrane proteins, some are involved in
transport and form channels/pores, others act as carriers that bind a substance, some are enzymes,
others are receptors for hormones that relay messages through signal transduction
Peripheral Proteins- attached loosely, easily removed without disrupting membrane, include network
of filaments that support membrane from cytoplasmic side, some enzymes, others motor proteins for
cell division, muscle cell contraction, link cells
Glycocalyx- glycoproteins with branching sugar groups, form a fuzzy, sticky, carb rich area at cell surface,
different pattern of sugars providing highly specific biological marker allowing cells to recognize one another
Cell Junctions- glycoproteins in glycocalyx act as adhesive, wavy contours of membranes fit together, other
special cell junctions
1. Tight junctions- impermeable junction formed by series of integral proteins
2. Desmosomes- anchoring junctions scattered like rivets along sides of cells, on face of each plasma
membrane is button-like thickening called plaque, adjacent cells held together by thin linker protein
filaments (cadherins) that extend from plaques and fit together like Velcro, abundant in skin and heart
muscle
3. Gap junctions- nexus, connected by hollow cylinders (connexons) composed of transmembrane
proteins, ions, simple sugars, molecules pass through, present in electrically excitable tissues such as
heart and smooth muscle
Diffusion-tendency of molecules to move from area of high concentration to area of low concentration,
driving force in kinetic energy influenced by molecular size and temp
Simple diffusion- nonpolar lipid-soluble substance diffuses directly through lipid bilayer
Facilitated diffusion- certain molecules (glucose) transported passively by binding to protein carrier
Carrier-mediated facilitated diffusion- transmembrane integral proteins specific for transporting certain polar
molecules that are too large to pass through channels, alter shape of carrier to envelop and release
transported substance allowing to bypass nonpolar regions of membrane
Channel-mediated facilitated diffusion- transmembrane proteins that transport substances (ions/water)
through aqueous channels from one side of membrane to other, selective due to pore size and charge of
amino acid
Leakage channels- always open allowing ions to move by concentration gradient
Gated channels- controlled by chemical or electrical signal
Osmosis-diffusion of solvent such as water through cell membrane, moves freely through water-specific
channels called aquaporins (AQPs) allowing single file diffusion, as solute concentration increases water
concentration decreases
Osmolarity- concentration of all solute particles in a solution
Hydrostatic pressure- back pressure exerted by water against membrane
Osmotic pressure- tendency of water to move into cell by osmosis
Tonicity- ability of solution to change shape/tone of cells by altering internal water volume
Isotonic- solutions have same concentrations of non-penetrating solutes as cells
Hypertonic- higher concentration of nonpenetrating solutes then in cell, cells lose water and shrink
(crenate)
Hypotonic- dilute concentration of nonpenetrating solutes, cells plump up as water rushes in, distilled
water contains no solutes, cells burst (lyse)
Active Transport- requires carried-mediated facilitated diffusion, requires carrier proteins that combine
specifically and reversibly with transported substances, solute pumps move solutes/ions against concentration
gradients done by expelling energy
Primary- energy comes directly from hydrolysis of ATP, results in phosphorylation of transport
protein, protein changes shape as it pumps (Na+ and K+ pump)
Secondary- indirectly by energy stored in concentration gradients of ions created by primary
active transport pumps, coupled systems moving more than one substance a time
Symport system- two transported substances move in same direction
Antiport system- transported substances cross in opposite directions
Vesicular Transport- fluid containing large particles and macromolecules transported across cell membranes
inside bubble-like sacs called vesicles, energized by ATP or GTP
Endocytosis- coated pit ingests substance, protein-coated vesicle detaches, coat proteins are recycled
to plasma membrane, uncoated vesicle fuses with a sorting vesicle called endosome, transport vesicle
containing membrane components moves to plasma membrane for recycling, fused vesicle may fuse
with lysosome for digestion of contents or deliver them to opposite side of cell
Phagocytosis- cell eating, bacteria, cell debris, inanimate objects, particles, pseudopods form and flow
around the particle creating endocytotic vesicle called phagosome, fuses with lysosome and contents
digested
Pinocytosis- cell drinking, fluid phase endocytosis, infolding plasma membrane surrounds small volume
of extracellular fluid containing dissolved molecules, droplet enters cell and fuses with endosome,
routine activity
Receptor-mediated Endocytosis- extracellular substances bind to specific receptor proteins enabling
cell to ingest and concentrate specific substances (ligands) in protein-coated vesicles
Exocytosis- eject substances from cell interior, stimulated by cell-surface signal such as a binding
hormone to receptor, cell enclosed in secretory vesicle, migrates to plasma membrane, fuses then
ruptures spilling contents out of cell
Involves v-SNAREs “docking” process and t-SNAREs recognition of target plasma membrane proteins
Membrane potential- voltage across the membrane, electrical potential energy resulting from separation of
oppositely charged particles
Resting membrane potential- -50 to -100 mV, all cells said to be polarized, diffusion causes ionic
imbalances that polarize membrane, active transport maintain membrane potential
K+- predominate inside body cells, , unstimulated plasma membrane is somewhat permeable to K+ but
impermeable to protein anions , K+ diffuses out of cell along its concentration gradient, this loss of
positive charge makes interior more negative, negativity of inner membrane becomes great enough to
attract K+ back into cell, at voltage of -90mV K+ concentration is exactly balanced
Na+- strongly attracted to cell interior by concentration gradient bringing resting membrane potential
to -70mV, K+ still largely determines because membrane is more permeable to K+
Electrochemical Gradients- steady state, the rate of active transport of Na+ out depends on rate of Na+
diffusing in, each turn of the pump ejects 3Na+ out and carries 2K+ back in, the pump maintains both
membrane potential and osmotic balance, diffusion of K+ across plasma membrance is aided by membrane’s
greater permeability to it, negative charges on cell interior resist K+ diffusion
Cell Adhesion Molecules- found on every cell of body, key role in embryonic development, wound repair,
immunity, sticky glycoproteins (Cadheinrs/integrins) act as molecular Velcro, arms that migrating cells use to
haul themselves past one another, SOS signals that rally protective white blood cells, mechanical sensors that
response to changes in local tension or fluid movement, transmitters of intracellular signals that signal
migration, proliferation, specialization
Plasma Membrane Receptors
Contact signaling- cells come together and touch, means by which cells recognize one another,
important for development and immunity
Chemical signaling- ligands bind specifically to plasma membrane receptors, include
neurotransmitters, hormones, paracrines (act locally and are rapidly destroyed), different cells react
differently to same ligand
G-protein linked receptors- exert their effect indirectly through a g protein, a regulatory molecule that
acts as a middleman, generating one or more intracellular chemical signals called second messengers
that connect plasma membrane events
Cyclic AMP & Ionic calcium- activate protein kinase enzymes, transfer phosphate groups from
ATP to other proteins activating series of enzymes that bring about cellular activity
Cytoplasm- intracellular fluid, material between plasma membrane and nucleus, site of activity
Cytosol- viscous, semitransparent fluid, complex mixture, comprised of water, proteins, salts, sugars
and solutes
Inclusions- chemical substances, may or may not be present, stored nutrients such as glycogen
granules in liver and msulce, lipid droplets in fat cells, pigment such as melanin in certain skin/hair cells
Organelles- metabolic machinery of cell, little organs
Mitochondria- power plant providing most ATP supply, enclosed by 2 membranes, outer is smooth and inner
forms shelf-like cristae that protrude into the matrix, breaks down metabolites releasing energy used to attach
phosphate to ADP creating ATP, contain their own DNA, RNA and ribosomes, able to reproduce themselves
Ribosomes- small granules composed of proteins and RNAs, two globular subunits that fit together like an
acorn, sites of protein synthesis
Free- float in cytosol, make soluble proteins that function in cytosol and those imported
Membrane bound- attached to endoplasmic reticulum forming complex, synthesize proteins destined
for incorporation into cell membranes or lysosomes or for export
Endoplasmic Reticulum- extensive system of interconnected tubes and parallel membranes enclosing fluidfilled cavity called cistern, continuous with outer nuclear membrane
Rough-studded with ribosomes, proteins assembled on these ribosomes thread way into cistern, when
complete they are enclosed in vesicles for journey to golgi apparatus, cell’s membrane factory where
proteins and phospholipids manufactured, enzymes that catalyze lipid synthesis have active sites here
Smooth- tubules arranged in looping network, enzymes play no role in protein synthesis, catalyze
reactions involved with lipid metabolism, synthesis of steroid based hormones,
absorption/synthesis/transport of fats, detoxification of drugs, chemicals, break down stored glycogen
to form free glucose
Sarcoplasmic reticulum- in skeletal and cardiac muscles, smooth ER that stores and releases Ca+ during
muscle contraction
Golgi Apparatus- stacked and flattened membranous sacs, traffic director, modify, concentrate, package
proteins and lipids made at rough ER
1. Transport vesicles off rough ER move to and fuse with convex cis face the receiving side
2. Inside apparatus, proteins are modified
3. Proteins are tagged for delivery to specific address, sorted, packaged from trans face
Secretory vesicles/granules- contain proteins destined for export, discharged from cell through exocytosis,
incorporated into plasma membrane or packed into membranous lysosomes to remain in cell
Peroxisomes- spherical sacs containing powerful enzymes (oxidases, catalases), use O2 to detoxify alcohol,
formaldehyde, neutralize free radicals converting them to hydrogen peroxide which catalases convert to
water, numerous in liver and kidney cells, synthesize fatty acids
Lysosomes- disintegrators, contain activated digestive enzymes, large and abundant in phagocytes to dispose
of bacteria and debris, also called acid hydrolases, digest particles taken in by endocytosis, degrading
stressed/dead cells, perform metabolic functions such as glycogen breakdown, breakdown bone to release
calcium ions, membrane is fragile when deprived of O2 and when excess vitamin A is present, when ruptures
the cell digests itself (autolysis)
Endomembrane System- organelles that work to produce, degrade, store, export biological molecules and
degrade potentially harmful substances, includes ER, GA, vesicles, lysosomes and nuclear membrane
Cytoskeleton- network of rods running through cytosol and accessory proteins that link rods to other cell
structures, acts to support cell structure
Microfilaments- semiflexible strands of protein actin, dense cross-linkages called terminal web,
involved in cell motility or changes in cell shape, interact with myosin to generate contractile forces,
actin forms cleavage furrow that pinches in cell division
Intermediate filaments- tough, insoluble protein fibres resembling ropes, made of tetramer fibrils,
most stable and permanent, high tensile strength, attach to desmosomes, act as internal guy-wires to
resist pulling forces, ex) keratin
Microtubules- largest diameter, hollow tubes made of protein subunits called tubulin, radiate from
small region of cytoplasm near nucleus called centrosome, consistently growing, disassembling then
reassembling, determine overall shape of cell and distribution of organelles, protein machines called
motor proteins (kinesins, dyneins) move and reposition organelles
Centrosome- cell centre, acts as microtubule organizing center, granular looking matrix
Centrioles- small, barrel-shaped oriented at right angles, pinwheel array of nine triplets of microtubules
connected to the next by nontubulin proteins arranged to form hollow tube, basis of cilia and flagella (basal
bodies),
Cilia- whip-like motile cell extensions, moves substances in one direction across cell surface, activity
coordinated with microtubules, motor protein dynein, collective bending of all doublets
Flagella- longer, sperm, one propulsive flagellum commonly called a tail, propels the cell itself ie) sperm
Power stroke- propulsive nearly straight
Recovery stroke- bends and returns to its initial position
Microvilli- minute, fingerlike projections of plasma membrane, increase surface area, found on absorptive
cells such as intestines and kidney, core of bundled actin filaments that extend into terminal web of cell
Nucleus- control center, genetic library, contains instructions needed to build all body’s proteins, dictates
kinds and amounts of proteins to be synthesized, mature RBCs are anucleate
Nuclear envelope- double membrane barrier separated by fluid filled space, continuous with rough ER,
contains nuclear pores forming aqueous transport channel and regulating entry and exit of molecules,
encloses nucleoplasm
Nucleoli- ribosomal subunits assembled, make large amount of tissue proteins, contain DNA that issues
genetic instructions for synthesis of rRNA
Chromatin- composed of DNA, histone proteins which package and regulate DNA and RNA chains
Nucleosomes- flattened disc shaped cores/clusters of histone proteins connected like beads on a string
by DNA molecule, DNA winds twice around each nucleosome and continues on to the next cluster via
linker segments
Histones- means for packing very long DNA molecules in compact and orderly way
Chromosomes- condense to form short bar-like bodies to prevent tangling and breaking during cell
division
Extracellular materials- substances contributing to body mass outside the cells
Body fluids- interstitial fluid, blood plasma, cerebrospinal fluid, important for transport and dissolving
media
Cellular secretions- substances that aid in digestion, lubricants
Extracellular matrix- most abundant, jellylike substance composed of proteins and polysaccharides,
self-assemble into organized mesh, serve as “cell glue” to hold body cells together
Cell Cycle
1. Interphase- which cell grows and carries its usual activities, period of cell formation to division,
metabolic/growth phase
a. G1- cell metabolically active, synthesizing proteins rapidly and growing vigorously, more
variable in terms of length, G0- cells that permanently stop dividing
b. S phase- DNA replication, ensuring identical copies, new histones made and assembled into
chromatin
c. G2- enzymes and other proteins needed for division synthesized and moved to their proper
sites, centriole replication is complete, check to see if all DNA is replicated
2. Mitotic phase-cell division
DNA Replication
1. Uncoiling- enzymes unwind the DNA molecule forming a replication bubble
2. Separation- the 2 DNA strands separate as the hydrogen bonds between base pairs is broken, point at
which strands unzip known as replication fork
3. Assembly- with old strands acting at templates, enzyme polymerase positions complementary free
nucleotides along template strands forming 2 new strands, leading and lagging strands synthesized in
opposite directions, two new daughter molecules result, mechanism known as semiconservative
replication since each new molecule consists of one old and one new nucleotide strand
4. Restoration- ligase enzymes splice short segments of DNA together, restoring double helix structure
Cell Division- essential for body growth and tissue repair
Mitosis- division of the nucleus, series of events that parcels out he replicated DNA of mother cell to 2
daughter cells
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Meiosis- produces sex cells (ova and sperm) with only half the number of genes found in other body cells
Cytokinesis- division of cytoplasm, begins during late anaphase and is completed after mitosis ends,
contractile ring made of actin filaments draws plasma membrane inward to form a cleavage furrow over the
centre of the cells, deepens until it pinches the cytoplasmic mass into 2 parts
Cell Division Control- ratio of cell surface area to cell volume, chemical signals like growth hormones,
availability of space, proteins such as cyclins and cyclin-dependent kinases
DNA- master blueprint for protein synthesis
Gene- segment of DNA molecule that carries instructions for creating one polypeptide chain
Triplet- each sequence of three bases, specifies a particular amino acid, variations of A, C, T, & G
Exons- genes of higher organisms, informational sequences
Introns- noncoding, repetitive segments, serve as reservoir for ready to use DNA segments
RNA
Messenger- long nucleotide resembling half DNA molecule, carries coded info to cytoplasm
Ribosomal- forms ribosomes which consist of subunits one large and one small, combine to form
functional ribosomes which are sites of protein synthesis
Transfer- small, roughly L-shaped molecules that ferry amino acids to ribosomes, decode mRNA
message for amino acid sequence in polypeptide
Transcription- DNA’s info encoded in mRNA, transcription factors stimulate histones at the gene transcription
site to loosen, bind to the promotor/start point, specifies which DNA strand will be template strand vs. coding
strand, RNA polymerase initiates transcription
1. Initiation- RNA polymerase pulls apart strands of DNA double helix so transcription can begin
2. Elongation- using incoming RNA nucleotides as substrates, RNA polymerase aligns them with
complementary DNA bases on template strand and then links them together, as RNA polymerase
elongates mRNA strand one base at a time, it unwinds DNA helix in front and rewinds helix behind
3. Termination- polymerase reaches special base sequence called termination signal, newly formed
mRNA separates from DNA template
Translation- info carried by mRNA decoded and used to assemble polypeptides
Genetic code- rules which base sequence of gene is translated into amino acid sequence, for each triplet on
DNA the corresponding three base sequence on mRNA is called a codon, code for amino acids or “stop”
codons, some amino acids specified by more than one codon, anticodon found on tRNA to bind to
corresponding codon
1. Initiation- small ribosomal subunit binds to special methionine-carrying initiator tRNA, new mRNA to
be decoded, small ribosomal subunit scans along mRNA until it encouters start codon (AUG triplet),
UAC anticodon on tRNA recognizes and bind to start codon, large ribosomal subunit unites with small
one, forming functional ribosome
2. Elongation- ribosome moves along mRNA in one direction and one amino acid at a time is added to
growing polypeptide
a. Codon recognition- incoming aminoacyl-tRNA binds to complementary codon in A site of
ribosome
b. Peptide bond formation- enzymatic component in large ribosomal subunit catalyzes peptide
bond formation between amino acid of tRNA in the P site to that of the tRNA in the A site
c. Translocation- ribocome translocates, shifting its position one codon along the mRNA, shift
moves tRNA in A site to P site, unloaded tRNA is transferred to E site, from which it is released
and ready to be recharged with another acid from cytoplasmic pool
3. Termination- mRNA strand is read sequentially until last codon, “stop codon” reads UGA, UAA or UAG,
enters A site, tells the ribosome that translation of that mRNA is finished, water is added to
polypeptide chain, hydrolyzes the bonds between polypeptide and tRNA in the P site
Rough ER Processing- short “leader” peptide ER signal sequence is present in protein being synthesized, the
associated ribosomes attaches to membrane of rough ER, guided to appropriate receptor sites by signal
recognition particle, a protein chaperone that cycles between ER and cytosol
MicroRNAs- small RNAs that can use RNA interference machinery to interfere with/suppress mRNA made by
certain exons, silencing them
Riboswitches- folded RNAs that look like tRNAs, region that acts as a switch to turn protein synthesis on/off in
response to metabolic changes in immediate enviro, stopping or starting production
Small interfering RNAs- originate outside cell, make them from an infecting virus’s DNA and they act to
interfere with viral replication
Autophagy- self eating, sweeps up bits of cytoplasm and excess organelles into vesicles called
autophagosomes, delivered to lysosomes for digestion of contents which the cell reuses, may have evolved as
response to cell starvation, speeds up in response to stress
Ubiquitins- proteins mark doomed proteins for attack (proteolysis) by attaching to them, tagged proteins are
hydrolyzed to small peptides by soluble enzymes or proteasomes (waste disposal complexes), critical during
starvation when these complexes degrade preexisting proteins to provide amino acids for synthesis of new
and needed proteins
Apoptosis- programmed cell death, rids body of cells that are programmed to have limited lifespan, eclls lining
uterus in menstruating woman, does not use the services of lysosomes,
Cell Aging
Wear and Tear theory- cumulative effects of assaults such as enviro toxins leads to accelerated cell death
Mitochondrial theory- places blame on damage caused by free radicals, resulting in diminished energy
production by damaged mitochondria
Immune theory- aging results from progressive weakening of immune system, body loses its ability to fight off
pathogens or to heal systemic inflammation which is associated with aging and risks for chronic disease
Genetic theory- holds that cell aging is programmed into our genes, telomeres are nonsensical strings of
nucleotides that cap the ends of chromosomes, providing protection, carry no genes but vital for
chromosomal survival, each DNA replication causes telomeres to become shorter