Welcome to ANP 213

• Introduction, Syllabus and Attendance

• Chapter 1- Overview of Anatomy and Physiology

• Chapter 2- Chemistry Review

Chapter 1

• “Form fits function”• Homeostasis• Levels of organization

What is ‘ANP’?

• Anatomy-

• Physiology-

Form Fits Function

• Are anatomy and physiology really that different?

• You need to understand the parts and how they are put together to know how they work

• If you know what a body structure does, you can usually predict how it is organized to do its job

Another Example

Radius

Ulna

19 hand

bones!

Why does this bone have a huge hole in it?

Vertebral foramen

Homeostasis

• Homeostasis-• Or-• Significance of maintaining homeostasis?

– Examples • Both the nervous system and endocrine

system play important roles in maintaining homeostasis

Seattle

Link

Homeostasis and Feedback Loops

• All systems involve three components: a ‘receptor’, a control center and an effector

RECEPTOR (ie. free

nerve ending in the skin)

CONTROL CENTER(such as the brain)

EFFECTOR(such as a muscle,

or a gland)

Stimulus (input into the system)

The response to the stimulus leads to change. The change is ‘fed back’ to the

receptor.

Response(system’s output)

Homeostasis and Feedback Loops

• In negative feedback a stimulus causes a response which works to reduce/counteract the stimulus– Stabilizing– Examples?

• In positive feedback a stimulus causes a response which further increases the stimulus– Examples?

To truly understand ANP, we have to start small

• How small?• Chemistry small!• How big is an atom?

The approximate atomic radius of an atom of gold is 0.1441 nanometers or 0.1441 x 10-9 meters (i.e. 0.1441 millionth of a millimeter!)

Remember that all living things are made of cells

CARBON ATOM

Macromolecules

organism

Living things exhibit “Levels of Organization”

Molecular: DNA

Cellular: Kidney Cell

Tissue: Kidney Tissue

Organ: Frog Kidney

Organismal: A frog

CellsNucleus within cell

Life begins at the cell

Molecules: Nucleic Acids

A Cell

DNA is a macromolecule, comprised of many molecules. Molecules are made up of atoms!!

nucleus

Carbon atom

Macromolecule: DNA

Chapter 2- Chemistry review• What is Chemistry?• Atoms and Subatomic Particles• Chemical Bonds• H2O

• Hydrophilic, hydrophobic• Chemical Reactions• Enzymes• Organic compounds-

Macromolecules

• Chemistry-

• Matter-

• Smallest stable units of mass are atoms

CLIFFS NOTES

CHEMISTRY

Why is Chemistry Important to Anatomy and Physiology?

CARBON ATOM

+

+

• Atoms are composed of 3 subatomic particles

The Structure of Atoms

1. Protons

2. Neutrons

3. Electrons ]

Packed in the atomic nucleus

Orbit the nucleus

How many electrons does a carbon atom have?

CARBON ATOM

+

+

The Structure of Atoms

How many protons, neutrons and electrons does a helium atom have?

What is the overall charge, if any, of a helium atom?

HELIUM ATOM

Elements• Mass of an atom is determined by the # of protons

and neutrons…atomic weight• Atoms can be classified into groups called

elements• Each element has its own atomic number• You can find all of them on the periodic table

CARBON ATOM

Atomic number

+

+

How many elements are found in the human body?

• 13 principal elements– Oxygen, carbon, hydrogen, nitrogen,

calcium, phosphorous, potassium, sodium, chlorine, magnesium, sulfur

• 13 trace elementsIron, iodine, zinc, etc.

Atoms have electrons in electron shells

Electron Shells• The first electron shell holds only 2 electrons• The next electron shell holds up to 8 electrons• The four elements most abundant in living things

only have these two shells

In case you forgot those four elements, they are:

HYDROGENCARBON

NITROGENOXYGEN

Atoms of the four elements most abundant in the human body

Electron

Firstelectron shell(can hold2 electrons)

Outermostelectron shell(can hold8 electrons)

Carbon (C)Atomic number = 6

Nitrogen (N)Atomic number = 7

Oxygen (O)Atomic number = 8

Hydrogen (H)Atomic number = 1

Atoms ‘prefer’ to have their outer shell FILLED with electrons-

The Octet Rule

Oxygen (O)Atomic number = 8

Hydrogen (H)Atomic number = 1

I, HYDROGEN, would prefer to

have 2 electrons in my outer shell, and

not just 1!

I, OXYGEN, would strongly prefer to have 8 electrons in

my outer shell, and not 6!

The Bumper Car Analogy

Oxygen (O)Atomic number = 8

Hydrogen (H)Atomic number = 1

I would prefer to have 2

electrons in my outer

shell, and not just 1!

I would strongly prefer to have 8

electrons in my outer shell, and

not 6!

Atoms can ‘fill’ their outer electron shells by forming chemical bonds with

other atoms

• Octet Rule• Atoms can steal electrons from other atoms;

atoms can lose electrons to other atoms– Ions and Ionic bonds

• Atoms can share electrons with another atom or atoms– Covalent bonds

Chemical Bonds

• Ionic bonds• Covalent bonds

– Polar covalent bonds• Hydrogen bonds

Ionic bonds are formed between ions

• Remember that the atoms we have discussed so far are electrically neutral

• They are neutral because the number of protons (+) was equal to the number of electrons (e-)

• An ion is a charged species– Anions– Cations

Anions and Cations• If an atoms gains an electron (e-), what happens to

its electrical charge?

• If an atom loses an electron (e-) what happens to its electrical charge?

Formation of a sodium ion, Na+

e-e-

e-

e-

e-e-

e-

e-

Ionic bonds are formed between ions

Covalent bonds occur when atoms share electrons

or H-H or H2H H

e- e-

A single covalent bond is formed between two hydrogen atoms. The two atoms share a pair of electrons.

The two electrons then orbit around both atoms’ nuclei.

Covalent Bonds

• For every pair of electrons shared between two atoms, a single covalent bond is formed. 

– In H2 there is ONE covalent bond

• Some atoms can share multiple pairs of electrons, forming multiple covalent bonds.

Everyone is happy

when they

share.

Methane is a simple compound, consisting of one atom of carbon and 4 hydrogen atoms.

In methane, Carbon has four covalent bonds to 4 different hydrogen atoms

Covalent Bonds

CH

H

H

H

Covalent Bonds

• Are strong because the shared electrons hold the atoms together

• Typically, the atoms involved in covalent bonds remain electrically neutral

• Found in most of the carbon-containing structural components of living things

H H

e- e-

Covalent bonds are a true sharing of electrons

Ionic and covalent bonds form…• Molecules- a chemical structure containing two or

more atoms that are held together by covalent bonds

• Compounds- a chemical substance made of atoms of 2 or more different elements

Polar Covalent Bonds

• Polar covalent bonds are a type of covalent bond

• Characterized by an unequal sharing of electrons

e- Unfair!

Polar Covalent Bonds

• Polar covalent bonds form because some atoms have a stronger affinity for electrons than do other atoms

• Electronegativity

e-

Strongly electronegative

Polar covalent bonds can result in polar molecules

• In a polar covalent bond, one atom ‘pulls’ on electrons more tightly than the other atom

• The more electronegative atom ‘hogs’ electrons • Thus, electrons will spend more time (on average)

around the electronegative atom• A slight or partial negative charge results around this

end of the molecule • The ‘electronegative’ end of the molecule has a

parital negative charge

Water (H2O) is a polar molecule

• Water (H2O) is one oxygen atom bound to two hydrogen atoms

• Oxygen is a strongly electronegative atom – Oxygen is an electron (e-) hog– Oxygen has a strong desire for electrons,

and once it has them, it ‘pulls’ on them very tightly

• Oxygen forms polar covalent bonds with hydrogen atoms

• H2O is a polar molecule

oxygen

Oxygen (O)Atomic number = 8Hydrogen (H)

Atomic number = 1

What will happen when an atom of OXYGEN ‘sees’ an atom of ‘HYDROGEN’?

..Two atoms of HYDROGEN??

Hydrogen (H)Atomic number = 1

Polar Covalent Bonds: H2O

e- e-

Polar Covalent Bonds: H2O

Animation of the valence electrons of water molecule

Polar covalent bonds can result in polar molecules

2δ-

δ+

δ+

Partial negative charge

Partial positive charge

What happens when one water molecule ‘sees’ another water

molecule?

H

O

H

H

O

H

Which of these orientations do you think is correct?

2δ-

A. B. C.

POP QUIZ

Hydrogen bonding

• Weak but important forces • Can exist between adjacent molecules, or

regions of a single molecule• Occur when (partial negative ) δ- is attracted

to (partial positive ) δ+ of a Hydrogen atom

Hydrogen bonds are weak (but biologically important) bonds

•Hydrogen bonding between water molecules is transient (short-lived)

•Hydrogen bonding keeps water molecules very tightly associated with one another

Water animation

Phew, what chemistry have we covered so far?

• What is chemistry?• Smallest stable unit in chemistry is _____.• What are subatomic particles? What are their

charges? • What is the octet rule?

Why do we care? • List three types of chemical bonds.What chemical bonds exist within ONE water

molecule? Between two different water molecules?

Blah, blah, blah, blah blah….