A&P Studying (Current)

Module 1 — A&P Refined Study Guide

1.1A — Define Anatomy

Anatomy is the study of the structures of the body and how those structures are organized.

Example: Studying the structure of the heart, including its chambers, valves, and blood vessels, is anatomy.

Remember:

Anatomy = structure

1.1B — Describe the levels at which anatomy can be studied

Anatomy can be studied at different levels, including the:

• Chemical level — atoms and molecules

• Cellular level — cells

• Tissue level — groups of similar cells

• Organ level — two or more tissue types working together

• Organ-system level — multiple organs working together

• Organism level — the entire human body

1.1C — Define Physiology

Physiology is the study of how the body and its parts function.

Example: Studying how the heart pumps blood is physiology.

Remember:

Anatomy = what it is/what it looks like
Physiology = what it does/how it works

1.1D — Describe the levels at which physiology can be studied

Physiology can be studied at the:

• Cellular level — how cells function

• Organ level — how organs function

• Organ-system level — how systems function

• Organism level — how the entire body functions

1.1E — Relationship Between Structure and Function

Structure and function are closely related because the structure of a body part allows it to perform its specific function.

Example: The lungs contain millions of tiny air sacs called alveoli. Their thin walls and large surface area make them well-suited for exchanging oxygen and carbon dioxide.

Key idea:

Structure determines or supports function.

A body part's shape, size, and organization help determine what it can do.

1.2A — Why Study Other Organisms?

Studying other organisms is important because scientists can learn about human anatomy, physiology, diseases, and treatments by studying organisms with similar biological processes.

Example: Certain medications and medical procedures are first studied in animals to understand how they might affect humans.

Key idea:

Other organisms can help us understand how the human body works and how diseases can be treated.

1.3A — Six Levels of Organization

Memorize these in order:

1. Chemical

2. Cellular

3. Tissue

4. Organ

5. Organ system

6. Organism

A simple way to think about it:

Chemicals → Cells → Tissues → Organs → Organ Systems → Person

1.3B — Characteristics of the Six Levels

1. Chemical

Made of atoms and molecules.

Example: Water, oxygen, proteins, DNA.

2. Cellular

Made of cells, the basic structural and functional units of life.

Example: Muscle cell.

3. Tissue

A group of similar cells working together to perform a function.

Example: Muscle tissue.

4. Organ

Contains two or more tissue types working together.

Example: The heart contains muscle, nervous, connective, and epithelial tissues.

5. Organ System

Multiple organs working together to perform major functions.

Example: The digestive system includes the stomach, intestines, liver, pancreas, etc.

6. Organism

The entire living individual, with all organ systems working together.

Example: You.

1.3C — The 11 Organ Systems

This is a high-priority memorization section.

1. Integumentary

Components: Skin, hair, nails, sweat glands, oil glands.

2. Skeletal

Components: Bones, cartilage, ligaments, joints.

3. Muscular

Components: Skeletal muscles and associated tendons.

4. Nervous

Components: Brain, spinal cord, nerves, sensory organs.

5. Endocrine

Components: Hormone-producing glands such as the pituitary, thyroid, adrenal, and pancreas.

6. Cardiovascular

Components: Heart, blood, blood vessels.

7. Lymphatic

Components: Lymph, lymphatic vessels, lymph nodes, thymus, spleen, and other lymphatic organs.

8. Respiratory

Components: Nose, nasal cavity, pharynx, larynx, trachea, bronchi, lungs, and other airways.

9. Digestive

Components: Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus, plus accessory organs such as the liver, gallbladder, and pancreas.

10. Urinary

Components: Kidneys, ureters, urinary bladder, urethra.

⚠ Important correction: You wrote uterus. It is ureters, not uterus.

• Ureters = tubes carrying urine from kidneys → bladder

• Uterus = female reproductive organ

11. Reproductive

Components:
Male — testes and associated structures.
Female — ovaries, uterine tubes, uterus, vagina, and associated structures.

1.3D — Functions of the 11 Organ Systems

Integumentary

Protects the body, helps regulate temperature, prevents water loss, and provides sensation.

Skeletal

Provides support and protection, allows movement with muscles, stores minerals, and produces blood cells.

⚠ Remember: bone marrow produces blood cells.

Muscular

Produces movement, maintains posture, and generates heat.

Nervous

Provides rapid control and communication throughout the body and allows sensation, thought, memory, and responses.

Endocrine

Produces hormones that regulate body functions such as growth, metabolism, reproduction, and blood glucose.

Cardiovascular

Transports oxygen, carbon dioxide, nutrients, hormones, wastes, and heat throughout the body.

Lymphatic

Helps maintain fluid balance, absorbs certain fats, and provides immune defense.

Respiratory

Brings oxygen into the body and removes carbon dioxide through gas exchange.

Digestive

Breaks down food, absorbs nutrients and water, and eliminates solid waste.

Urinary

Removes wastes from the blood and helps regulate water, electrolytes, blood pressure, and acid-base (pH) balance.

Reproductive

Produces sex cells and hormones and allows reproduction.

1.4A — Six Characteristics of Life

Your list is correct:

1. Organization

2. Metabolism

3. Responsiveness

4. Growth

5. Development

6. Reproduction

1. Organization

Living things have organized structures.

Example: Cells → tissues → organs → organ systems.

2. Metabolism

All chemical reactions occurring in the body.

Example: Breaking down food to obtain energy.

3. Responsiveness

Ability to detect and respond to changes in the environment.

Example: Pulling your hand away from something hot.

4. Growth

An increase in size or number of cells.

Example: A child getting taller.

5. Development

Changes that occur throughout an organism's life.

Example: A child going through puberty.

6. Reproduction

The production of new cells or new organisms.

Example: Cells dividing or humans producing offspring.

1.5A — Define Homeostasis

Homeostasis is the maintenance of relatively stable internal conditions despite changes in the external environment.

It doesn't mean everything stays exactly the same. It means the body keeps conditions within a normal range.

Example: Your body temperature stays around 37°C (98.6°F) even when the temperature outside changes.

Remember:

Homeostasis = keeping the body's internal environment stable.

1.5B — Why Is Homeostasis Important?

Homeostasis is important because cells need relatively stable conditions to function properly.

If conditions become too far outside the normal range, cells and organs may not function correctly.

Example: If your body temperature becomes extremely high, enzymes and cells can stop functioning properly.

1.5C — Negative Feedback

A negative-feedback mechanism reverses or reduces a change in the body.

Example: Body temperature

1. Body temperature rises.

2. The brain detects the increase.

3. Sweat glands produce sweat.

4. Sweating helps cool the body.

5. Body temperature moves back toward normal.

Change → response reverses the change.

Another example:

Blood glucose rises after eating → insulin is released → blood glucose decreases.

Remember:

Negative feedback = brings things back toward normal.

1.5D — Positive Feedback

A positive-feedback mechanism strengthens or increases the original change.

Childbirth example:

1. Baby pushes against the cervix.

2. Cervix stretches.

3. Brain releases oxytocin.

4. Oxytocin increases uterine contractions.

5. Stronger contractions push the baby harder against the cervix.

6. More stretching → more oxytocin → stronger contractions.

The cycle continues until childbirth occurs.

Remember:

Positive feedback = amplifies the change.

⚠ Easy test distinction:

Negative feedback → reverses change
Positive feedback → increases change

1.6A — Anatomical Position

The anatomical position is:

• Standing upright

• Facing forward

• Head facing forward

• Arms at the sides

• Palms facing forward

• Feet directed forward

⚠ Palms facing forward is important.

1.6B — Directional Terms

These are very important to memorize.

Two you REALLY need to understand:

Proximal vs. distal

Think about your arm:

Shoulder → elbow → wrist → fingers

As you move away from the shoulder:

Proximal → → → Distal

1.6C — Parts and Regions of the Body

The body can be divided into the:

Axial region

The head, neck, and trunk.

Appendicular region

The upper and lower limbs.

Head — cephalic

Contains the skull, brain, eyes, nose, mouth, and ears.

Neck — cervical

Connects the head to the trunk.

Trunk

Includes the thorax (chest), abdomen, and pelvis.

Upper limb

Shoulder → arm → forearm → wrist → hand

Lower limb

Hip → thigh → leg → ankle → foot

⚠ Remember:

Arm ≠ entire upper limb

Technically, the arm is the section between the shoulder and elbow.

Likewise:

Leg ≠ entire lower limb

Technically, the leg is the section between the knee and ankle.

1.6D — Three Major Body Planes

You have one important mistake here.

Sagittal plane

Divides the body into right and left portions.

Median (midsagittal) plane

Divides the body into equal right and left halves.

Frontal (coronal) plane

Divides the body into anterior (front) and posterior (back) portions.

Transverse (horizontal) plane

Divides the body into superior (upper) and inferior (lower) portions.

⚠ Your notes incorrectly said transverse divides anterior/posterior.

Remember:

Sagittal = right/left
Frontal = front/back
Transverse = top/bottom

1.6E — Three Major Ways to Cut an Organ

Same concept as the planes.

Sagittal section

Cuts an organ into right and left portions.

Frontal section

Cuts an organ into anterior and posterior portions.

Transverse section

Cuts an organ into superior and inferior portions.

⚠ Your sagittal explanation was incorrect. It does not mean "cuts from left to right." Think about the result:

Sagittal → right/left

1.6F — Major Trunk Cavities and Divisions

The two major trunk cavities are:

1. Thoracic cavity

The chest cavity.

Contains:

• Lungs

• Heart

• Trachea

• Esophagus

• Other structures

The thoracic cavity contains:

Pleural cavities → lungs

Mediastinum → central region between the lungs

Pericardial cavity → heart

2. Abdominopelvic cavity

Divided into:

Abdominal cavity → stomach, intestines, liver, spleen, etc.

Pelvic cavity → urinary bladder, reproductive organs, rectum, etc.

Think of it like this:

Thoracic
→ Pleural cavities
→ Mediastinum
→ Pericardial cavity

Abdominopelvic
→ Abdominal cavity
→ Pelvic cavity

1.6G — Organs in Cavities, Quadrants, and Regions

Major cavities

Thoracic cavity

Contains:

• Heart

• Lungs

• Trachea

• Esophagus

Abdominal cavity

Contains:

• Stomach

• Liver

• Gallbladder

• Spleen

• Pancreas

• Small intestine

• Most of large intestine

• Kidneys

Pelvic cavity

Contains:

• Urinary bladder

• Rectum

• Internal reproductive organs

The Four Abdominal Quadrants

Imagine a cross dividing the abdomen into four equal sections.

Right Upper Quadrant — RUQ

Major organs include:

• Liver

• Gallbladder

• Right kidney

• Part of small/large intestines

Left Upper Quadrant — LUQ

Major organs include:

• Stomach

• Spleen

• Left kidney

• Part of pancreas/intestines

Right Lower Quadrant — RLQ

Major structures include:

• Appendix

• Cecum

• Right ovary and uterine tube

Left Lower Quadrant — LLQ

Major structures include:

• Sigmoid colon

• Left ovary and uterine tube

⚠ Important: Right and left refer to the patient's right and left, not yours when you're looking at them.

The Nine Abdominal Regions

This is worth memorizing because professors LOVE asking about it.

Think of a 3 × 3 grid:

Top row

Right hypochondriac — Epigastric — Left hypochondriac

Middle row

Right lumbar — Umbilical — Left lumbar

Bottom row

Right iliac — Hypogastric — Left iliac

⚠ You were missing the right/left lumbar regions.

Also, one correction:

Umbilical region is mainly associated with the small intestine, not specifically the urinary bladder.

Hypogastric region can contain the urinary bladder and small intestine.

1.6H — Serous Membranes

The three major serous membranes are:

Pleura

Associated with the lungs.

• Parietal pleura = lines the thoracic cavity

• Visceral pleura = covers the lungs

Pericardium

Associated with the heart.

• Surrounds/protects the heart.

Peritoneum

Associated with the abdominal cavity.

• Lines the abdominal cavity

• Covers many abdominal organs

Why do we have serous membranes?

They produce a small amount of serous fluid, which reduces friction between organs as they move.

Example: Your lungs expand and contract constantly. The pleura and serous fluid help the lungs move smoothly against surrounding structures.

Know where the major organs are located.

2.1 BASIC CHEMISTRY

1. Matter, mass, and weight

Matter

Matter = anything that occupies space and has mass.

Examples:

• Your body

• Water

• Oxygen

• Food

• Bones

• 
  

Mass

Mass = amount of matter in something.

The SI unit for mass is the kilogram (kg).

Weight

Weight = gravitational force acting on an object.

Easy distinction

Mass = how much stuff you have.

Weight = how strongly gravity pulls on that stuff.

2. Elements and atoms

Element

An element is the simplest type of matter with unique chemical properties.

An element contains only one type of atom.

Examples:

• Hydrogen → H

• Carbon → C

• Oxygen → O

• Nitrogen → N

The four most common elements in the human body are:

H → C → N → O

Hydrogen, carbon, nitrogen, and oxygen.

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Other important elements include:

• Sodium → Na

• Potassium → K

• Calcium → Ca

• Chlorine → Cl

• Iron → Fe

• Magnesium → Mg

• Iodine → I

• Phosphorus → P

• Sulfur → S

These may be present in much smaller amounts but are extremely important for body function.

3. The atom

An atom is the smallest particle of an element that still has the chemical characteristics of that element.

Atoms contain three major subatomic particles:

The nucleus contains:

protons + neutrons

Electrons occupy the space surrounding the nucleus.

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Remember:

P = Positive

N = Neutral

E = Negative

4. Atomic number vs. mass number

This is VERY important.

Atomic number

Atomic number = number of protons

Every element is uniquely identified by its number of protons.

For a neutral atom:

protons = electrons

Example:

Carbon has atomic number 6.

Therefore carbon has:

• 6 protons

• 6 electrons

Mass number

Mass number = protons + neutrons

So if an atom has:

• 6 protons

• 6 neutrons

Mass number = 12

Memorize:

Atomic number → protons

Mass number → protons + neutrons

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5. Isotopes

Isotopes = different forms of the same element.

They have:

• Same number of protons

• Same atomic number

• Different number of neutrons

• Different mass numbers

The slides use hydrogen as the example.

Hydrogen has three isotopes:

• Protium → 1 proton, 0 neutrons

• Deuterium → 1 proton, 1 neutron

• Tritium → 1 proton, 2 neutrons

All are hydrogen because they all have one proton.

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Test question example

Two atoms both have 6 protons, but one has 6 neutrons and the other has 8 neutrons.

Are they different elements?

No.

They are isotopes of the same element.

6. Mole and Avogadro’s number

A mole is simply a huge counting unit.

Just like:

• 1 dozen = 12

• 1 mole = 6.022 × 10²³ particles

That number is called Avogadro’s number.

A mole can count:

• atoms

• ions

• molecules

Molar mass

The molar mass is the mass of one mole of a substance in grams.

You don’t necessarily need to think of a mole as “something chemical.”

Think:

mole = giant counting number

7. Chemical bonds

Atoms bond because their electrons—especially their valence electrons—determine how chemically reactive they are.

Valence electrons

These are electrons in the atom’s outermost energy level.

The chapter emphasizes the octet rule:

Atoms tend to become more stable when their outer shell contains 8 electrons.

If the valence shell isn’t full, the atom may form bonds to become more stable.

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8. Ionic bonds

Ionic bond = electrons are transferred

One atom loses electrons.

Another atom gains electrons.

This creates charged atoms called ions.

Cation

Cation = positive ion

It has lost electrons.

Think:

CATion = +

Anion

Anion = negative ion

It has gained electrons.

Example: NaCl

Sodium:

Na → loses an electron → Na⁺

Chlorine:

Cl → gains an electron → Cl⁻

Then:

Na⁺ + Cl⁻ → NaCl

The opposite charges attract.

That’s an ionic bond.

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Important ions in the body

Know the general roles:

• Ca²⁺ → bones/teeth, muscle contraction, blood clotting

• Na⁺ → membrane potentials, water balance

• K⁺ → membrane potentials

• H⁺ → acid-base balance

• Cl⁻ → water balance

• HCO₃⁻ → acid-base balance

• PO₄³⁻ → bones/teeth, energy exchange, acid-base balance

• Fe²⁺ → red blood cell formation

• Mg²⁺ → enzymes

• I⁻ → thyroid hormones

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9. Covalent bonds

Covalent bond = sharing electrons

Instead of transferring electrons like an ionic bond, atoms share electrons.

There are different types.

Single covalent bond

Two atoms share one pair of electrons.

Double covalent bond

Two atoms share two pairs of electrons.

10. Nonpolar vs. polar covalent

This is another major concept.

Nonpolar covalent

Electrons are shared equally.

Example:

H₂

Both hydrogen atoms attract the shared electrons equally.

So there isn’t a positive end and negative end.

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Polar covalent

Electrons are shared unequally.

One atom attracts the electrons more strongly.

The chapter uses water as the major example.

Oxygen attracts the shared electrons more strongly than hydrogen.

Therefore:

Oxygen → slightly negative (δ−)

Hydrogen → slightly positive (δ+)

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Think about it like this:

Nonpolar = equal sharing

Polar = unequal sharing

11. Molecules vs. compounds

Molecule

Two or more atoms chemically combined into an independent unit.

Examples:

H₂

H₂O

Compound

A substance containing two or more different types of atoms chemically combined.

Examples:

H₂O

NaCl

So:

Every compound contains different elements.

But a molecule doesn’t necessarily have different elements.

For example:

H₂ is a molecule but not a compound.

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12. Intermolecular forces

These are weak attractions between molecules.

They’re weaker than chemical bonds.

One especially important type:

Hydrogen bond

A slightly positive hydrogen is attracted to a negatively charged O, N, or F.

Water molecules form hydrogen bonds with one another.

Hydrogen bonds are also important in determining the shapes of complex molecules.

Covalent bond: holds atoms together inside a molecule.

Hydrogen bond: attracts different parts of molecules to each other.

13. Solubility and dissociation

Solubility

Solubility = ability of one substance to dissolve in another.

Example:

• Salt → dissolves in water

• Sugar → dissolves in water

• Oil → does not dissolve well in water

Dissociation

Dissociation means separation.

When NaCl is placed in water:

NaCl → Na⁺ + Cl⁻

Water molecules surround the ions and pull them apart.

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14. Electrolytes

An electrolyte is a substance that dissociates into ions in water and allows the solution to conduct electricity.

Examples include ionic substances such as salts.

Nonelectrolytes

They dissolve in water but do not dissociate into ions, so they don’t conduct electricity.

This matters because your body needs the proper balance of electrolytes for many physiological processes.

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2.2 CHEMICAL REACTIONS AND ENERGY

Now the chapter moves from:

“What are molecules?”

to:

“What do molecules DO?”

15. Chemical reactions

A chemical reaction occurs when atoms, ions, molecules, or compounds interact and chemical bonds are formed or broken.

Reactants

What you start with.

Products

What you end with.

Think:

Reactants → Products

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16. Synthesis reactions

Synthesis = putting things together.

Two or more smaller reactants combine to make a larger product.

A + B → AB

In the body, synthesis reactions are collectively called:

Anabolism

Anabolism is associated with:

• Growth

• Maintenance

• Repair

• Building carbohydrates

• Building proteins

• Building lipids

• Building nucleic acids

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17. Dehydration reactions

A dehydration reaction is a type of synthesis reaction where:

Water is produced.

Example conceptually:

A + B → AB + H₂O

This is important when molecules are built.

18. Decomposition reactions

This is the opposite.

Decomposition = breaking something apart.

AB → A + B

In the body, decomposition reactions are collectively called:

Catabolism

Examples:

• Digesting food molecules

• Breaking ATP into ADP + phosphate

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19. Hydrolysis

Hydrolysis is decomposition involving water.

Hydro = water

lysis = breaking apart

Water is split and its parts help break the larger molecule apart.

Easy memory trick

Dehydration → water comes OUT

Hydrolysis → water goes IN

20. Metabolism

This is a HUGE term.

Metabolism

The sum of all anabolic + catabolic reactions in the body.

So:

Metabolism = anabolism + catabolism

Anabolism:

BUILD

Catabolism:

BREAK

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21. Reversible reactions and equilibrium

Some reactions can go both directions.

Example:

CO₂ + H₂O ↔ H₂CO₃ ↔ H⁺ + HCO₃⁻

The double arrow means the reaction is reversible.

Equilibrium

At equilibrium:

rate of product formation = rate of reactant formation

This doesn’t mean the reaction stops.

Both directions are still occurring.

They’re just occurring at equal rates.

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22. Oxidation and reduction

This is extremely testable.

Oxidation

Loss of an electron

Reduction

Gain of an electron

Memory trick:

OIL RIG

Oxidation
Is
Loss

Reduction
Is
Gain

When one substance loses an electron, another gains it.

That’s an oxidation-reduction (redox) reaction.

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23. Energy

Energy

Capacity to do work.

Two major types discussed:

Potential energy

Stored energy.

Chemical bonds contain potential energy.

Kinetic energy

Energy associated with movement.

Think:

Potential = stored

Kinetic = moving

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24. Conservation of energy

Energy cannot simply appear or disappear.

It can change from one form into another.

For example:

Chemical energy → movement + heat

This is extremely important for understanding metabolism.

25. Heat

Heat is energy that moves from:

hotter object → cooler object

During metabolism, not all released energy gets captured for useful cellular work.

Some is released as heat.

That’s useful for mammals because heat helps maintain body temperature.

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26. Activation energy

A chemical reaction doesn’t necessarily happen just because reactants exist.

The molecules need enough energy to start the reaction.

Activation energy

Minimum energy needed to start a chemical reaction.

Think of it like a hill.

Reactants have to get over the hill before the reaction can happen.

27. Catalysts and enzymes

Catalyst

A substance that speeds up a chemical reaction without being permanently changed or depleted.

Enzyme

A protein catalyst.

Enzymes speed reactions by lowering activation energy.

Important:

Enzymes do NOT provide the energy for the reaction.

They make it easier for the reaction to get started.

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28. What affects reaction speed?

Two major factors emphasized:

Temperature

Higher temperature → molecules have more kinetic energy → move faster → collide more often/harder → reaction rate increases.

Concentration

Higher concentration of reactants → more collisions → faster reaction.

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2.3 INORGANIC CHEMISTRY

29. Organic vs. inorganic

Inorganic chemistry

Deals with substances that do not contain carbon-hydrogen bonds.

Examples:

• Water

• Oxygen

• CO₂

• Calcium phosphate

• Metal ions

Organic chemistry

Deals with carbon-containing substances.

The chapter specifically notes exceptions:

CO, CO₂, HCO₃⁻

contain carbon but lack C-H bonds, so they’re treated as inorganic.

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30. Water

Water is one of the most important substances in your body.

Why?

Because water is polar.

That means water has slightly positive and negative regions.

This allows water to interact with many substances.

31. Hydrophilic vs. hydrophobic

Hydrophilic

Water-loving

Attracted to water.

Hydrophobic

Water-fearing

Not attracted to water.

A major example of hydrophobic substances is lipids/oils.

32. Cohesion vs. adhesion

Cohesion

Water molecules stick to other water molecules.

Cohesion = water + water

This creates surface tension.

Adhesion

Water sticks to other substances.

Adhesion = water + something else

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33. Why water is important to the body

The chapter gives several functions.

Water:

• Helps stabilize body temperature

• Absorbs large amounts of heat

• Helps cool the body through evaporation

• Lubricates moving body parts

• Protects organs

• Provides a medium where many chemical reactions occur

• Helps transport substances throughout the body

The slides state that roughly 50–60% of the body and about 91% of blood are water.

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34. Solutions

Solution

A mixture where substances are uniformly distributed.

Solvent

The substance doing the dissolving.

Solute

The substance being dissolved.

Example:

Salt water:

• Water = solvent

• Salt = solute

Memory:

Solvent = solves/dissolves

35. Suspension vs. colloid

Suspension

Particles separate unless stirred.

Example:

Sand + water

Blood cells in plasma are also given as an example.

Colloid

Tiny particles are dispersed throughout a medium and don’t settle out.

Examples:

• Milk

• Plasma

• Cell interior

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36. Concentration

Concentration describes the amount of solute relative to the volume of solution.

Example:

A 10% NaCl solution contains:

10 g NaCl per 100 mL of solution.

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37. Osmolality

This is a more advanced concept.

Osmolality

Reflects the number of dissolved particles in 1 kg of water.

The average osmolality of body fluids is approximately:

300 mOsm

The concentration of body fluids affects movement of fluid into and out of cells.

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For now, think:

Osmolality = how many dissolved particles are present.

38. Acids

Acid = proton donor

An acid releases H⁺.

Example:

HCl → H⁺ + Cl⁻

More H⁺ generally means greater acidity.

39. Bases

Base = proton acceptor

A base accepts H⁺.

Many bases release OH⁻ when they dissociate.

Example:

NaOH → Na⁺ + OH⁻

And:

H⁺ + OH⁻ → H₂O

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40. Strong vs. weak acids/bases

Strong

Almost completely dissociate in water.

→ Lots of H⁺ or OH⁻

Weak

Only partially dissociate.

→ Fewer H⁺ or OH⁻

Weak acids/bases can establish equilibrium more readily.

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41. pH

pH tells you about the hydrogen ion concentration of a solution.

The scale

0 ← acidic — 7 — basic → 14

pH < 7

Acidic

More H⁺

pH = 7

Neutral

pH > 7

Basic/alkaline

More OH⁻

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VERY important

The pH scale is logarithmic.

So a change of 1 pH unit represents a 10× change in H⁺ concentration.

42. Blood pH

Normal blood pH:

7.35–7.45

That’s a very narrow range.

Below 7.35

Acidosis

The chapter describes nervous-system depression and possible disorientation/coma.

Above 7.45

Alkalosis

The nervous system can become overexcitable, with possible nervousness or convulsions.

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43. Buffers

This is one of the most important concepts in the chapter.

Buffer

A buffer is a solution containing a conjugate acid-base pair that resists changes in pH.

Think:

Buffer = pH stabilizer

If extra acid enters the solution:

The buffer’s conjugate base can grab the extra H⁺.

If extra base enters:

The conjugate acid can donate H⁺.

Therefore, the pH doesn’t change as dramatically.

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44. Biological buffers

The chapter identifies:

• Bicarbonate

• Phosphate

• Proteins

as important biological buffers.

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45. Oxygen and carbon dioxide

Oxygen (O₂)

Required in the final step of the series of reactions used to extract energy from food.

Carbon dioxide (CO₂)

Produced during breakdown/catabolism of organic compounds.

CO₂ is a metabolic waste product.

It combines with water in plasma and contributes to formation of H⁺, so it affects acid-base balance.

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2.4 ORGANIC CHEMISTRY

This is probably the biggest section to study.

There are four major organic molecules:

Carbohydrates

Lipids

Proteins

Nucleic acids

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46. Functional groups

Functional groups give organic molecules their distinctive properties.

The chapter includes:

• Hydroxyl

• Sulfhydryl

• Carbonyl

• Carboxyl

• Ester

• Amino

• Phosphate

You don’t just want to recognize their names—you should understand generally what they do.

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Important ones

Hydroxyl (-OH)
→ polar, hydrophilic, increases water solubility

Sulfhydryl (-SH)
→ found in cysteine; can form disulfide bonds

Carboxyl (-COOH)
→ can donate H⁺; acidic

Amino (-NH₂)
→ can accept H⁺; basic

Phosphate
→ very hydrophilic; important in ATP, phospholipids, and cell signaling

47. Carbohydrates

Carbohydrates contain:

C + H + O

They function as:

• Energy sources

• Structural materials

• Bulk for elimination

They’re generally water soluble.

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There are three major categories:

1. Monosaccharides

One sugar.

Examples:

• Glucose

• Fructose

• Galactose

These six-carbon sugars can provide energy.

Isomers

Molecules with the same types and numbers of atoms but different arrangements.

Glucose, fructose, and galactose are examples.

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48. Disaccharides

Two monosaccharides joined together.

They’re formed through a dehydration reaction.

Examples:

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49. Polysaccharides

Long chains of monosaccharides.

Examples:

Glycogen

Made by animals.

Starch

Made by plants.

Cellulose

Made by plants and provides dietary fiber.

Polysaccharides can function as energy-storage molecules and can be involved in cell surface markers.

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50. Lipids

Lipids are mostly:

C + H + O

They are relatively insoluble in water.

Functions include:

• Energy storage

• Protection

• Insulation

• Cell membranes

• Physiological regulation

Major types include:

• Triglycerides

• Phospholipids

• Eicosanoids

• Steroids

• Fat-soluble vitamins

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51. Triglycerides

Triglycerides are the major form of fat in the human body.

A triglyceride contains:

1 glycerol + 3 fatty acids

Fatty acids are carbon chains with a carboxyl group at one end.

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52. Saturated vs. unsaturated fats

Saturated

• All single bonds

• More rigid structure

• Generally solid

Unsaturated

• One or more double bonds

• More relaxed structure

• Generally liquid

Monounsaturated = one double bond

Polyunsaturated = multiple double bonds

The slides also discuss trans fats as artificially altered unsaturated fats and identify them as having high cardiovascular risk.

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53. Phospholipids

Phospholipids are extremely important because they form much of the structure of cell membranes.

They have:

Hydrophilic head

Likes water.

Hydrophobic tails

Avoid water.

The chapter describes the molecule as having a polar phosphate-containing region and nonpolar fatty-acid region.

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Easy picture

HEAD = water-loving

TAILS = water-fearing

This property is fundamental to how cell membranes form.

54. Eicosanoids

Eicosanoids are derived from fatty acids.

They act as regulatory molecules.

Examples:

• Prostaglandins

• Thromboxanes

• Leukotrienes

55. Steroids

Steroids are lipids with a characteristic:

4-ring structure

An important steroid is:

Cholesterol

Cholesterol is a starting material for:

• Bile salts

• Many steroid hormones

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56. Proteins

Proteins contain:

C + H + O + N

and sometimes:

S

Proteins have MANY functions:

• Regulation

• Transport

• Protection

• Muscle contraction

• Structure

• Energy

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57. Amino acids

Amino acids = building blocks of proteins

There are 20 different amino acids.

Every amino acid has a basic structure containing:

• Amino group

• Carboxyl group

• Hydrogen

• Central carbon

• R group/side chain

The R group is what makes the amino acids different from each other.

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Think:

Same basic structure + different R group = different amino acid

58. Peptide bonds

Amino acids are connected by peptide bonds.

A peptide bond is a covalent bond formed during protein synthesis through a dehydration reaction.

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So:

Amino acid + amino acid → peptide bond + H₂O

59. Protein structure

This is VERY important.

There are four levels.

Primary

Amino acid sequence

Think:

“What order are the amino acids in?”

Secondary

Hydrogen bonding causes parts of the amino acid chain to form:

• Helices

• Pleated sheets

Tertiary

The protein undergoes large-scale 3-D folding.

Interactions with the surrounding environment, especially water, influence the folding.

Nonpolar regions tend to fold inward away from water.

Disulfide bonds can help stabilize the structure.

The final shape is important because it helps determine the protein’s function.

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Quaternary

Two or more protein subunits come together.

Easy way to remember all four:

Primary = sequence

Secondary = local folds

Tertiary = overall 3-D shape

Quaternary = multiple subunits

60. Denaturation

A protein’s shape is extremely important.

Denaturation

A change in protein shape caused by disruption of its bonds/interactions.

The slides specifically mention heat or pH changes breaking hydrogen bonds and changing protein shape.

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Think:

Denaturation = protein loses its normal shape

And because protein function depends on shape, changing its shape can affect its function.

61. Enzymes

Enzymes are proteins that act as catalysts.

They:

• Lower activation energy

• Bring reactants close together

• Have a specific 3-D shape

• Have an active site

The reactants bind to the active site.

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62. Lock-and-key vs. induced fit

Lock-and-key model

The substrate fits into the active site like a key into a lock.

Induced fit

The enzyme changes its shape somewhat to better accommodate the substrate.

The chapter includes both models.

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63. Cofactors and coenzymes

Some enzymes need additional nonprotein substances to work properly.

Cofactor

Nonprotein substance that helps make an enzyme functional.

Coenzyme

An organic cofactor, often derived from vitamins.

64. Nucleic acids

Nucleic acids are made of:

Nucleotides

The chapter includes:

• DNA

• RNA

• ATP

Each nucleotide contains:

1. Five-carbon sugar

2. Nitrogenous base

3. Phosphate group

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65. DNA

DNA contains two strands of nucleotides.

The bases pair specifically:

A ↔ T

G ↔ C

These are called complementary base pairs.

The bases are held together by hydrogen bonds.

The two strands twist into a:

Double helix

The strands are also antiparallel, meaning their sugar-phosphate backbones run in opposite directions.

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66. Gene

A gene is a sequence of bases that codes for the synthesis of RNA or a protein.

The DNA base sequence ultimately determines the primary structure of a protein.

Think:

DNA sequence → instructions → protein

67. ATP

This is one of the most important concepts in the entire chapter.

ATP = adenosine triphosphate

The chapter calls ATP the body’s energy currency.

Why?

Because ATP can store energy and release it to power cellular processes.

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ATP provides energy for things such as:

• Chemical reactions

• Anabolism

• Muscle contraction

• Other cell processes

68. ATP ↔ ADP

ATP can be thought of as the cell’s rechargeable energy carrier.

Storing energy:

ADP + Pi + energy → ATP

Energy from breaking down nutrients can be stored in ATP.

Releasing energy:

ATP → ADP + Pi + energy

That released energy can then power cellular processes.

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Think of it like this:

Food → energy → ATP → cellular work

ATP is essentially the middleman.

⭐ THE MOST IMPORTANT THINGS TO MEMORIZE

If you have limited time, focus heavily on these.

Chemistry

• Matter

• Element

• Atom

• Proton / neutron / electron

• Atomic number

• Mass number

• Isotopes

• Valence electrons

• Octet rule

Bonds

• Ionic = transfer

• Covalent = share

• Nonpolar = equal sharing

• Polar = unequal sharing

• Hydrogen bond = weak attraction involving H

Ions

• Cation = positive

• Anion = negative

Reactions

• Reactants = start

• Products = result

• Synthesis = build

• Decomposition = break

• Anabolism = building

• Catabolism = breaking

• Dehydration = water produced

• Hydrolysis = water used to break something

• Oxidation = loss of electrons

• Reduction = gain of electrons

Energy

• Potential = stored

• Kinetic = movement

• Activation energy = energy needed to start

• Enzyme = lowers activation energy

Water/pH

• Hydrophilic = water-loving

• Hydrophobic = water-fearing

• Cohesion = water + water

• Adhesion = water + another substance

• Acid = gives H⁺

• Base = accepts H⁺

• pH < 7 = acidic

• pH 7 = neutral

• pH > 7 = basic

• Normal blood pH = 7.35–7.45

• Buffer = resists pH changes

Organic molecules

Carbohydrates → energy

Lipids → energy storage, membranes, insulation, regulation

Proteins → structure, enzymes, transport, contraction, regulation, etc.

Nucleic acids → genetic information / ATP

4.1 Tissues and Histology

What is a tissue?

Tissue = a group of specialized cells + the extracellular substances surrounding them.

Think:

Tissue = cells working together + material around them

Histology

Histology = the microscopic study of tissues.

Studying tissues can provide information about a person's health.

• Biopsy → tissue is removed from a living person for diagnosis.

• Autopsy → examination of a dead body to determine the cause of death.

The 4 Primary Tissue Types

You need to know these four:

How are tissues classified?

Tissues are classified based on:

1. Cell structure

2. Extracellular matrix

3. Cell function

4.2 Embryonic Tissue

Early in development, the embryo forms three germ layers.

These layers eventually produce all tissues of the body.

The 3 Germ Layers

Think:

Endo = inside
Meso = middle
Ecto = outside

Neural Crest Cells

Some cells break away from the neuroectoderm and become neural crest cells.

They form:

• Peripheral nerves

• Skin pigment cells

• Adrenal medulla

• Some tissues of the face

Easy way to remember

Endo → inside
Meso → middle
Ecto → exterior

4.3 Epithelial Tissue

Big Picture

Epithelial tissue:

• Covers body surfaces

• Lines organs and body cavities

• Forms glands

Think:

Epithelial = covering + lining + glands

Characteristics of Epithelial Tissue

1. Mostly cells

Epithelial tissue contains:

• Lots of cells

• Very little extracellular matrix

This is different from connective tissue, which has lots of extracellular matrix.

2. Has distinct surfaces

An epithelial cell has different sides:

Apical surface

• Faces the free/open space

• Also called the free surface

Basal surface

• Faces the underlying tissue

• Attached to the basement membrane

Lateral surface

• Contacts neighboring epithelial cells

Think:

Apical = away/open
Basal = bottom
Lateral = neighboring sides

Basement Membrane

The basement membrane connects the epithelial tissue to the underlying connective tissue.

It has two major layers:

1. Basal lamina

2. Reticular lamina

Basal Lamina

The basal lamina contains:

• Lamina lucida

• Lamina densa

What is the basement membrane made of?

It contains specialized extracellular material including:

• Collagen

• Glycoproteins

  • Laminin

  • Fibronectin

• Proteoglycans

Functions of the basement membrane

It:

• Supports epithelial cells

• Helps guide cell migration during tissue repair

• Allows materials to move between epithelial cells and underlying tissue

Epithelial Tissue is Avascular

Avascular = no blood vessels.

Epithelial tissue does not have its own blood supply.

Therefore:

Nutrients and oxygen must diffuse from the underlying connective tissue.

Epithelial tissue also regenerates quickly

Epithelial cells have a high regeneration capacity.

This makes sense because epithelial tissue is often exposed to:

• Friction

• Injury

• Chemicals

• Microorganisms

Functions of Epithelial Tissue

There are 5 major functions you should know:

Memory trick:

P-B-P-S-A

Protection
Barrier
Passage
Secretion
Absorption

Classification of Epithelial Tissue

There are two main ways to classify epithelial tissue:

1. Number of cell layers

2. Shape of cells

A. Classification by Number of Layers

Simple

Simple = one layer

Every cell reaches:

Basement membrane → free surface

Key idea:

Simple = 1

Stratified

Stratified = multiple layers

The shape of the cells at the apical surface determines the name.

Example:

Stratified squamous

means multiple layers with squamous cells on the top.

Key idea:

Stratified = stacked

Pseudostratified

Looks like multiple layers, but isn't.

All cells actually contact the basement membrane.

Therefore:

Pseudostratified = actually simple

The nuclei appear to be at different heights, making it look layered.

Transitional

A special type of stratified epithelium.

Its cells can change shape when the tissue is stretched.

Example:

Urinary bladder

When relaxed → cells appear more cuboidal/columnar.

When stretched → cells become flatter, more squamous-like.

Key idea:

Transitional = changes shape

B. Classification by Cell Shape

There are three basic shapes:

Squamous

Flat and thin

Think:

Squamous = squashed

Cuboidal

Approximately equal in:

• Height

• Width

Think:

Cube = cuboidal

Columnar

Taller than they are wide

Think:

Column = tall

Put the Two Classification Systems Together

When you see an epithelial name, break it apart.

For example:

Simple squamous

Simple → one layer

Squamous → flat cells

Therefore:

One layer of flat cells.

Stratified cuboidal

Stratified → multiple layers

Cuboidal → top cells are cube-shaped

Epithelial Surface Modifications

The apical/free surface can have different modifications.

Smooth Surface

A smooth surface can reduce friction.

Endothelium

Endothelium = specialized epithelial lining associated with blood vessels.

Folds

Folds allow an organ to change shape.

Example:

Urinary bladder

Microvilli

Microvilli increase surface area.

This helps with:

• Absorption

• Secretion

Think:

Microvilli = more surface = more absorption

Stereocilia

Specialized microvilli that function as sensory receptors.

Example:

Inner ear

⚠ Important:

Stereocilia are NOT cilia.

Cilia

Cilia move substances across the epithelial surface.

Examples:

• Move mucus

• Move oocytes in the uterus/uterine tubes

Think:

Cilia = move things

Cell Connections

Epithelial cells need to connect to one another and to the basement membrane.

Cell connections have three major purposes:

1. Form a permeability layer

2. Hold cells together

3. Allow communication between cells

There are four major types:

• Desmosomes

• Hemidesmosomes

• Tight junctions

• Gap junctions

Also know adhesion belts.

1. Desmosomes

Desmosomes = strong cell-to-cell attachment

They are especially important in areas exposed to mechanical stress.

They contain:

• Adhesive material between cells

• Intermediate filaments extending into the cytoplasm

Think:

Desmosome = spot weld between cells

2. Hemidesmosomes

Hemidesmosomes = attach epithelial cells to the basement membrane.

Think:

Hemi = half

A desmosome connects:

cell ↔ cell

A hemidesmosome connects:

cell ↔ basement membrane

3. Tight Junctions

Tight junctions = seal cells together.

They:

• Hold cells together

• Form a permeability barrier

• Prevent substances from easily passing between cells

Think:

Tight = sealed

4. Adhesion Belt

Found just below tight junctions.

They:

• Anchor epithelial cells together

• Add strength

• Help prevent substances from passing between cells

Think:

Adhesion belt = extra support

5. Gap Junctions

Gap junctions = communication channels.

They allow:

• Ions

• Small molecules

to pass directly from one cell to another.

Important example: cardiac muscle

Gap junctions allow electrical signals to travel from cell to cell.

This helps coordinate contraction of:

• Cardiac muscle

• Smooth muscle

Intercalated discs

Found between cardiac muscle cells.

They contain:

• Gap junctions

• Desmosomes

Think:

Gap junction = communication

Cell Junctions: What You REALLY Need to Remember

Fast memory system:

Desmosome = durable attachment

Hemidesmosome = half → basement membrane

Tight = tight seal

Gap = communication

Glands

Glands = specialized secretory organs made from epithelial tissue.

They have a supporting network of connective tissue.

There are two major types:

Endocrine vs. Exocrine

Endocrine

No duct

Produces hormones, which are released into the surrounding tissue/blood.

Think:

Endocrine = enters blood

Exocrine

Has a duct

The duct connects the gland to a surface.

Think:

Exocrine = exits through a duct

Exocrine Gland Classification

Exocrine glands can be classified according to:

1. Duct structure

2. Secretory portion shape

3. Method of secretion

Simple vs. Compound Glands

Simple glands

One unbranched duct

The secretory portion can be:

• Tubular

• Acinar (sac-like)

Examples of structural types:

• Simple tubular

• Simple branched tubular

• Simple acinar

• Simple branched acinar

Key:

Simple = single, unbranched duct

Compound glands

Many-branched ducts

The secretory portion can be:

• Tubular

• Acinar

• Both

Types:

• Compound tubular

• Compound acinar

• Compound tubuloacinar

Key:

Compound = branched duct system

Modes of Exocrine Secretion

This is HIGH-YIELD.

There are three:

Merocrine

Exocytosis

The cell releases the secretion without losing part of itself.

Most common type.

Think:

Mero = merely releases

Apocrine

The top portion of the cell pinches off with the secretion.

Examples:

• Mammary glands

• Ceruminous glands

Think:

Apo = a piece goes away

Holocrine

The entire cell breaks apart and becomes the secretion.

Example:

• Sebaceous glands

Think:

Holo = whole cell

The 3 Secretion Types

Memory:

Mero → most stays

Apo → part goes

Holo → whole goes

4.4 Connective Tissue

Big Picture

Connective tissue is:

• Abundant

• Found throughout the body

• Found in every organ

• Made of cells + extracellular matrix

The biggest difference from epithelial tissue:

Connective tissue has LOTS of extracellular matrix.

Functions of Connective Tissue

Know these:

1. Enclose organs

2. Connect tissues

3. Support and allow movement

4. Store energy

5. Cushion and insulate

6. Transport

7. Protect

Examples

Connective Tissue Cells

A major idea:

Connective tissue cells produce and maintain the extracellular matrix.

The names of many connective tissue cells tell you what they do.

The "Blast, Cyte, Clast" Rule

This is VERY important.

-blast

Builds/creates matrix

Blast = build

-cyte

Maintains matrix

Cyte = caretaker

-clast

Breaks down matrix

Clast = clears/breaks

Examples

Bone

Osteoblast → forms bone

Osteocyte → maintains bone

Osteoclast → breaks down bone

Cartilage

Chondroblast → forms cartilage

Chondrocyte → maintains cartilage

Fibrous connective tissue

Fibroblast → forms fibrous connective tissue

Fibrocyte → maintains fibrous connective tissue

Other Connective Tissue Cells

Adipocytes

Adipocytes = fat cells

They store fat.

Mast Cells

Common:

• Beneath membranes

• Along small blood vessels

Important in inflammation.

They can release:

• Histamine

• Heparin

• Proteolytic enzymes

Think:

Mast cells = inflammation

White Blood Cells / Leukocytes

Respond to:

• Injury

• Infection

Think:

Leukocytes = immune defense

Macrophages

Macrophages = large cells that eat/destroy foreign and damaged material.

They perform phagocytosis.

Think:

Macro = big

Phage = eat

So:

Macrophage = big eater

Two types

Fixed macrophages

• Stay in one location

Wandering macrophages

• Move through connective tissue

• Use amoeboid movement

Platelets

Platelets are:

Fragments of hematopoietic cells involved in blood clotting.

Key idea:

Platelets → clotting

Undifferentiated Mesenchymal Cells

These are a type of adult stem cell.

They can differentiate into multiple cell types.

Think:

Mesenchymal cells = connective tissue stem cells

Extracellular Matrix

The extracellular matrix of connective tissue has 3 major components:

1. Protein fibers

2. Ground substance

3. Fluid

Think:

Matrix = fibers + ground substance + fluid

Protein Fibers

There are three major types:

1. Collagen Fibers

Most common protein in the body.

Properties:

• Strong

• Flexible

• Inelastic

Think:

Collagen = strong

It provides structural strength.

2. Reticular Fibers

Form branching networks.

They help fill spaces between:

• Tissues

• Organs

Think:

Reticular = net

Reticular fibers form a net-like network.

3. Elastic Fibers

Allow tissues to:

Return to their original shape after being stretched or compressed.

They contain elastin.

Think:

Elastic = stretch → return

The elastin molecules are cross-linked and resemble coiled springs.

Connective Tissue Classification

Connective tissue is classified based on the proportions of:

• Cells

• Extracellular matrix

• Matrix components

Two major categories:

1. Embryonic connective tissue

2. Adult connective tissue

Embryonic Connective Tissue

Two types:

Mesenchyme

An embryonic connective tissue.

It contains cells that can develop into various connective tissues.

Mucous Connective Tissue

Another type of embryonic connective tissue.

the most common types of cancer are from epithelial tissue with its more

rapid cell division.

• Carcinomas – cancers of epithelial tissue; include nearly all lung, breast,

colon, prostate, and skin cancers.

• Adenocarcinomas – derived from glandular epithelium.

Sarcomas – relatively rare cancers of mesodermal tissue (connective and

muscular).

Effects of Aging on Tissues 1

• Cells divide more slowly.

• Rate of blood cell synthesis declines.

• Injuries don’t heal as readily.

• Collagen fibers become more irregular in structure, though they may

increase in number; tendons and ligaments become less flexible and

more fragile.

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© McGraw Hill LLC.

Effects of Aging on Tissues 2

Changes in collagen and elastin result in

• Arterial walls and elastic ligaments become less elastic.

• Atherosclerosis and reduced blood supply to tissues.

• Wrinkling of the skin.

• Increased tendency for bones to break.

Slide 82

Skin repair:

• Secondary union: edges of wound are not close; greater chance of

infection.

• The clot may not completely close the gap.

• It takes longer for epithelial tissue to regenerate and cover the wound.

• Generally, more inflammation, more risk of infection, and more pus.

• More granulation tissue forms, and contraction of the fibroblasts leads

to wound contracture that results in disfiguring scars.

• It is advisable to suture a large wound so it can heal by primary union

instead of secondary union.

Skin repair is an example of tissue repair.

• Primary union: edges of wound are close together.

• Wound fills with blood.

• Clot forms: fibrin threads start to contract; pull edges together.

• Scab forms.

• Inflammatory response; pus forms as white cells die.

• Granulation tissue replaces clot, delicate C.T. composed of

fibroblasts, collagen fibers, capillaries.

• Scar formed from granulation tissue. Tissue turns from red to white as

capillaries are forced out.

Classification of cells based on ability to regenerate

• Labile cells: capable of mitosis through life; skin, mucous membranes,

hematopoietic tissue, lymphatic tissue.

• Stable cells: no mitosis after growth ends, but can divide after injury;

liver, pancreas, endocrine cells.

• Permanent cells: if killed, replaced by a different type of cell; limited

regenerative ability; nervous tissue, skeletal and cardiac muscle

Tissue repair: substitution of viable cells for dead cells by regeneration or

replacement.

• Regeneration: new cells of same type produced; function restored.

• Replacement: new type of tissue develops, resulting in scar and loss of

some function.

4.8 Tissue Damage and Inflammation

Body responds to tissue damage or infection with an inflammatory

response.

• Mobilize immune defenses, destroy infection, remove foreign materials

and damaged cells, initiate tissue repair.

Manifestations:

• Redness, heat, swelling, pain, disturbed function.

Chemical mediators

• Include histamine, kinins, prostaglandins, leukotrienes.

• Vasodilation, increase vessel permeability speed arrival of WBC’s to

affected area.

• Tissue swells, called edema.