Anatomy - the study of the structure of body parts & their relationship to one
another
Physiology - the study of the function of the body's structural machinery
Fields: Renal Physiology is the study of kidney function; Neurophysiology is the study of nervous system function...
Principle of
complementarity of structure & function: the function of structure depends on its structural form
Levels of Structural
Organization in Organisms:
Chemical Level: Atoms/Elements
(carbon, hydrogen, oxygen, sodium...)
Molecules/Compounds
(sugar, salt, water...)
Macromolecules
(proteins, lipids, carbohydrates, nucleic acids)
Organelles
(mitochondrion, nucleus, plasma membrane...)
Tissue Level
Organ Level
Organ System Level
Organismal Level
Anatomical Position: standing straight, facing forward with feet slightly
apart, arms at sides & palms of the hands facing forward.
Know the definitions of
& be able to apply:
Anatomical Terms - see textbook
Planes & Sections of the
body - see textbook
Know the location of each
of the following. Also know the
subdivisions where appropriate (for example: the pleural cavity is within the
thoracic cavity, which in turn is within the ventral body cavity).
Dorsal Body Cavity
-
Cranial cavity
-
Vertebral or Spinal cavity
Ventral Body Cavity
-
Thoracic cavity
-
Abdominopelvic cavity
Abdominopelvic Quadrants
Organ Systems:
-
Integumentary System (chapter 5): skin & accessory organs
-
Support & Movement
o Skeletal System (chapter 6)
o Muscular System (chapter 7)
-
Integration &
Coordination
o Nervous System (chapter 8)
o Sense Organs (chapter 9)
o Endocrine System (chapter 10)
-
Maintenance of the Body
o Circulatory System (chapter 12)
o Lymphatic System (chapter 13)
o Respiratory System (chapter 14)
o Digestive System (chapter 15)
o Urinary System (chapter 16)
-
Reproduction &
Development
o Reproductive System (chapter 17)
Negative Feedback: the product or response shuts off or reduces the
level of the original stimulus; the variable then changes in a direction
opposite the initial change
Examples of negative
feedback mechanisms: regulation of
body temperature, the withdrawal reflex, regulation of blood glucose levels by
the hormones insulin & glucagons
Positive Feedback - the product or response enhances or exaggerates he
original stimulus such that the response is continued
Examples of positive
feedback mechanisms: blood clotting,
labor contractions during birth
Homeostatic Imbalance - some lack of ability to activate/carry out control
mechanisms - age is one factor
-
matter is composed of elements
-
states of matter: solid, liquid
or gas
Elements are composed of atoms
Atoms are composed of subatomic particles:
-
protons (+ charge)
-
neutrons (no charge)
-
electrons (- charge)
The atomic number of an atom = the number of protons in its nucleus
-
the periodic table is grouped
according to atomic number (Hydrogen (H) has an atomic number of 1, Helium (He)
has an atomic number of 2...)
The atomic mass (mass number) of an atom is the number of protons + the number
of neutrons in its nucleus
-
the mass of electrons is
negligible
-
Hydrogen (H) has a mass number
of 1 (no neutrons), Helium (He) has a mass number of 4...
The atomic weight of an element is the average of the relative weights
of all the isotopes of that
element (the atomic weight of Hydrogen is 1.008).
Isotopes are atoms of an element that have the same number of
protons (atomic number) but different mass numbers (different numbers of
neutrons).
-
Examples: 12C,
13C, 14C
-
Radioactive isotopes are unstable isotopes that spontaneously decay into
more stable forms (it can take up to thousands of years for half the atoms in
an element to decay to the stable state)
-
Radioactivity can be
detected with scanning devices, & radioisotopes can be incorporated into
biological molecules...this makes radioisotopes useful tools for biological
research & medicine).
Carbon (C), Oxygen (O),
Hydrogen (H) & Nitrogen (N) make
up > 96% of the mass of a person
-
other elements in the human
body: Calcium (Ca), Phosphorus (P), Potassium (K), Sulfur (S), Sodium (Na),
Chlorine (Cl), Magnesium (Mg), Iron (Fe), Iodine (I)...
Molecules: 2 or more atoms held together by chemical bonds
-
when 2 or more atoms of the same element bind, they form a molecule
of that element
-
when 2 or more different atoms bind, they form one molecule of a compound
Chemical Bonds:
Electrons
of an atom differ in amount of potential (stored)
energy
-
electrons closest to the nucleus have the least potential energy (nonbonding electrons)
-
electrons farthest
from the nucleus have the greatest potential energy (valence or bonding electrons)
First
energy level can contain a maximum
of 2 bonding electrons
Second energy level, and all additional energy levels, can contain a maximum
of 8 bonding electrons
Octet rule: except for the first energy level, the
outermost energy level is most stable when it has 8 bonding electrons
(the first energy level is most stable with its maximum of 2 bonding electrons)
Bonding:
Ionic Bonding: transfer of electrons from one atom to another
-
results in ions: charged particles resulting from charge
imbalance
(greater or fewer electrons than protons) due to electron transfer
-
Examples: NaCl,
MgCl2, Na2O
-
Chemical formulas of compounds
based on # of valence electrons
(example: from above: MgCl2,
Mg has 2 valence electrons to donate, while Cl can
only accept 1, so two Cl atoms are needed to accept the 2 valence electrons
donated by one Mg atom)
Covalent bonding: sharing of electrons between 2 or more atoms
-
each atom acquires an octet of
valence electrons (electrons in outermost shell). Examples: CH4,
O2, H2, C6H12O6
-
water, H2O is formed by a polar covalent bond (unequal sharing
of electrons)
Hydrogen Bonding:
-
bond between a slightly
positive hydrogen atom of one molecule, and a slightly negative atom (usually oxygen or nitrogen)of the same or another molecule
-
weak bonding compared to ionic and covalent bonding, but
many bonds increases strength
-
good example is water
molecules
Biochemistry:
Inorganic Molecules:
Molecules which do not contain carbon and hydrogen (e.g.: salts, strong
acids and bases, metal compounds)
- usually ionic-bonding
Characteristics of Water:
-
resists changes in temperature (in part due to hydrogen bonding)
-
water has a high heat of
vaporization
⋅ high boiling point (100 degrees Celsius)
⋅ energy needed to break hydrogen bonds
⋅ water absorbs a lot of heat before evaporating
releases heat as it cools - helps keep body temperature constant
-
water is cohesive (water molecules stick together, also due to hydrogen
bonding)
⋅ cohesiveness allows water to fill tubular vessels in
body to transport & distribute molecules
-
water is the universal
solvent:
a. ionic
compounds : salts
b. polar covalent compounds
-
water dissociates or ionizes to release hydrogen ions and hydroxide ions
Electrolytes: substances that ionize, or break apart & release ions, when put into water
-
Acid:
molecules that release hydrogen ions (H+) when dissolved in
water
-
acids are hydrogen ion
(proton) donors
-
Base:
molecules that release hydroxide (OH-) ions , or increase the
number of hydroxide ions available, when dissolved in water
-
bases are hydrogen ion
(proton) acceptors
-
Salt: ionically-bonded molecule that dissociates into
cations & anions in solution
-
in the body, salts are electrolytes
that conduct electricity (important for nerve & muscle cells) & provide
essential chemical elements in body fluids (blood, lymph & interstitial
fluids)
pH scale (power of hydrogen): indicates acidity or basicity of
solution
-
ranges from 0 (strong acid) to
14 (strong base)
-
pH < 7 is acidic; pH > 7
is basic; pH = 7 is neutral
-
water ionizes to release equal numbers of hydrogen ions and
hydroxide ions (neutral)
Buffers:
maintain stable pH of solution (resist changes in pH)
-
Buffers can take up excess
hydrogen or hydroxide ions
-
Buffers have acidic and basic components
-
Blood uses carbonic acid (acidic) - bicarbonate ion (basic) buffer system
-
normal pH of blood is between
7.35 & 7.45
-
acidosis: blood pH < 7.35
-
alkalosis: blood pH > 7.45
-
Bicarbonate ions take up added
hydrogen ions, and carbonic acid takes up excess hydroxide ions
Organic Molecules: Carbon-based molecules
- Carbon
atoms are bonded mainly to atoms of hydrogen, oxygen,
and nitrogen, as well as some other atoms
- Always contain carbon and hydrogen
-
Always covalent-bonding
Synthesis &
degradation reactions used by organic macromolecules (carbohydrates, proteins, lipids, & nucleic
acids)
-
Dehydration synthesis
(condensation) reactions: formation
of a bond with removal of
water
-
Hydrolysis reactions: breaking of a bond by the addition of water
Carbohydrates: (contain carbon, hydrogen, and oxygen atoms)
Monosaccharides: simple
sugars with a backbone of 3 to 7 carbon atoms
-
Glucose is a 6-carbon sugar (hexose) found in the blood of animals, and Fructose is a hexose found in fruits
-
Ribose is a 5 carbon sugar (pentose) found in RNA (in DNA,
the pentose sugar is deoxyribose)
Disaccharides: 2 monosaccharides joined by condensation
-
Maltose (a disaccharide in the digestive tract) = glucose
+ glucose
-
Lactose ( a disaccharide in milk) = glucose + galactose (another hexose)
-
Sucrose (a disaccharide in fruits & vegetables) =
glucose + fructose
Polysaccharides:
-
Glycogen is a highly branched polymer of glucose, and is the storage form of carbohydrates in animal
cells (stored in liver cells)
-
Starch is a more moderately branched polymer of glucose, and is the storage form of carbohydrates in plant
cells
-
Cellulose is an unbranched polymer of glucose,
with adjacent chains held together by hydrogen bonds, giving it a very rigid structure. It is the major structural component of
plant cell walls
Lipids:
In
the form of neutral fats (fats or oils)
One
triglyceride = Glycerol + 3 fatty acids
-
Glycerol has 3 carbon atoms and 3 hydroxyl groups
-
Fatty acids have a long hydrocarbon (carbon + hydrogen) chain
with a carboxylic acid group at one end
-
Condensation joins a fatty acid to each of the hydroxyl groups in
glycerol
-
The condensation reaction
removes the ionizable functional groups from fatty acids and glycerol; hence,
these molecules are very hydrophobic
Saturated
fatty acids: each carbon atom in
the fatty acid molecules have the maximum number of bonded hydrogen
atoms (each carbon is saturated
with hydrogen atoms); there are no C=C double bonds
Unsaturated
fatty acids: one or more carbon
atoms in the fatty acid molecule has less than the maximum number of
bonded hydrogen atoms; there are one or more C=C double bonds
In
animal cells, neutral fats are in
the form of fats
-
fats are solid at room
temperature
-
fats contain more saturated
fatty acids
In
plant cells, neutral fats are in
the form of oils
-
oils are liquid at room
temperature
-
oils contain more unsaturated
fatty acids
Phospholipids = Glycerol + 2 fatty acids + 1 polar (phosphate-containing) head group (instead of
third fatty acid in triglyceride)
-
allows molecules to have hydrophobic end (2 fatty acids) and hydrophilic (phosphate) end
-
these molecules are the subunits of biological membranes in cells (e.g.: plasma membrane): the polar head group is in contact with
water on the inside and outside of the cell, and the hydrophobic fatty acid
chains are buried in the center of the membrane
Steroids are composed of 4 fused carbon
rings plus some variable
functional side group
-
Cholesterol is a structural
component of the plasma membrane
in animals, and is used in the synthesis of vitamin D and bile salts
-
Cholesterol is a precursor form of steroid that is modified to
produce several other types of steroids
-
Steroids function as hormones in animal cells
-
Accumulation of large amounts
of these bulky molecules in animals can lead to reduced blood flow and
hypertension (high blood pressure)
Proteins:
Proteins are composed of chains of amino acid monomers
-
There are 20+ different amino acids in cells of living organisms
-
Amino acids have a basic
core structure plus an
additional functional side chain
-
Each amino acid has a central
carbon bonded to an amino group,
a carboxylic acid group, a hydrogen
atom, and the remaining side chain (R
group); it is the R group that
differs in different amino acids
-
R groups can be nonpolar & hydrophobic, or polar
& hydrophilic, depending on the
atoms present
-
some proteins function as enzymes - organic catalysts that speed up chemical reactions
Polypeptide: a chain of many amino acids joined by peptide bonds
-
a protein can be composed of one or several polypeptide chains
-
condensation of two amino acids in a growing polypeptide chain
results in the formation of a peptide bond
-
hydrolysis of peptide bonds occurs between specific
amino acids in a protein by the activity of specific enzymes (e.g.: pepsin)
Protein
Structure
-
primary structure: the sequence of amino acids in a polypeptide chain
-
secondary structure: the
formation of discrete structures (alpha helices or beta pleated sheets) involving several amino acids within a polypeptide
chain (held together by hydrogen bonds)
-
tertiary structure: the
conformation of the polypeptide chain following interactions of regions of secondary
structure
o if the protein only consists of 1 polypeptide, this
is the final structure of the protein
-
quaternary structure: structure following interaction and bonding between two or more (the same or different) polypeptide chains
o hydrogen or ionic bonding between polypeptide chains
Denaturation:
disruption of specific 3D structure of a protein by increasing temperature (boiling) or changing pH
- may
be reversible (remember: the structure of a given
polypeptide is specific as well as consistent and reproducible)
Nucleic Acids:
Nucleic Acids are polymers
of nucleotide monomers
- a
nucleotide = a pentose
sugar + a phosphate + a nitrogenous (nitrogen-containing) base
- In RNA (Ribonucleic Acid), the pentose is ribose
- In DNA (Deoxyribonucleic Acid), the pentose is deoxyribose (missing a hydroxyl group at carbon # 2 relative to
ribose)
DNA:
DNA is the genetic material of the cell (inherited from parents)
-
composed of a sequence
of four different nucleotides
-
the 4 nucleotide
subunits of DNA are named after the nitrogenous base each contains; the 4 bases are : adenine (A)
cytosine (C)
guanine (G)
thymine (T)
-
DNA forms a double-helical structure
(DNA is double-stranded),
in which two chains bond together;
the sugar and phosphate groups are on the outside, and the nitrogenous
bases interact by hydrogen bonding in the middle of the double helix
-
A pairs with T through 2
hydrogen bonds; C pairs with G through 3 hydrogen bonds (stronger)
- the 2 strands (nucleotide chains) of the double helix are complementary:
RNA:
-
RNA is synthesized from 1 strand of DNA
-
RNA does not
form a double helix (no pairing of complementary bases between 2
strands); RNA is single-stranded
-
RNA also uses 4 nucleotide subunits; however, uracil (U) replaces thymine in RNA
-
major forms of RNA in
cells are: messenger RNA (mRNA), transfer RNA (tRNA) & ribosomal RNA (rRNA)
Genes in DNA code
for polypeptides: the sequence of
bases in DNA serves as a code for directing the sequence of bases in mRNA, and
then the sequence of amino acids in a protein
Chapter 3: Cells: The Living Units
Cells:
-
contain organelles: small,
membrane-bounded bodies with a specific structure & function (e.g.:
mitochondria, chloroplasts, lysosomes) in cytosol (semifluid medium between nucleus and plasma membrane)
-
cell wall in plant cells, fungi, protists, bacteria... for this
course we'll focus on animal cells, which have no cell wall
Plasma membrane: outer
boundary of cells (except plant cells - also cell wall)
-
phospholipid
bilayer: semipermeable and selectively permeable
-
functions in regulation
of passage of molecules into and out of the cell
-
fluid mosaic model: the
membrane is a fluid phospholipid bilayer, capable of lateral movement of
membrane components, in which various protein molecules are either partially or
wholly embedded
-
membrane
components:
-
phospholipids: create
bilayer
-
have polar &
nonpolar parts
-
glycolipids:
protective function, and cell identity (specific for cell type)
-
cholesterol: bulky;
controls (reduces) permeability
-
proteins: also glycoproteins; can be transmembrane (spans the entire membrane) or
embedded in either the cytoplasmic or extracellular side of the membrane
-
glycoproteins (and glycolipids) function in cell-cell recognition (cell fingerprint); important in transplantation
-
fluidity: Both
phosholipids and membrane proteins are capable of lateral movement
in the plasma membrane
-
phospholipids rarely
change from cytoplasmic to extracellular side of the bilayer, or vice-versa,
since the polar head group would have difficulty moving through the hydrophobic
center
-
the amount of movement
is dependent on composition of phospholipids, glycolipids, & cholesterol
Types of Membrane
Proteins:
Channel Proteins: create
transient hydrophilic
channel for small molecules & ions to flow into & out of cell
Carrier Proteins: selectively interact with small molecules or ions to assist them
across the membrane
Cell Recognition
Protein: Cell Identity; individual-specific groups of proteins on extracellular side of membrane (e.g.: MHC/HLA
(Human Leukocyte Antigen) - important to match with donor to avoid rejection of
transplanted organ or tissue)
Receptor Protein:
Interacts with specific molecule to transmit some type of signal or
communication (electrical, chemical or contact) between cells (e.g.: hormone receptors)
Enzymatic Protein:
Catalyzes (speeds up) some specific reaction which results in a cellular
response
Plasma Membrane is semipermeable and selectively permeable: some molecules may pass through freely (e.g.: water); others must be
assisted across
Microvilli: very small, fingerlike projections that project from
a free surface of some cells
-
increases surface for
absorption
Nucleus: stores genetic information in all eukaryotic cells
- &