Anatomy

Anatomy vs. Physiology

Anatomy

➡ The study of body structures and where they are located.

Example: The heart has four chambers.

Physiology

➡ The study of how body parts function/work.

Example: The heart pumps blood throughout the body.

🧠 Remember:
Anatomy = WHAT/WHERE
Physiology = HOW


2. Levels of Organization

From smallest → largest:

Cell → Tissue → Organ → Organ System → Organism

Cell

Smallest basic unit of life.

Tissue

Groups of similar cells working together.

Organ

Two or more tissue types working together.

Organ System

Multiple organs working together.

Organism

The entire living individual.

🧠 Easy way to remember:
Cells Together Organize Organ Systems
→ Cell → Tissue → Organ → Organ System → Organism


3. Body Cavities

Dorsal Cavity

Located toward the back/posterior side.

It has 2 major sections:

  1. Cranial cavity

    • Contains the brain.

  2. Vertebral (spinal) cavity

    • Contains the spinal cord.


Ventral Cavity

Located toward the front/anterior side.

Major sections include:

Thoracic cavity

Located in the chest.

Contains:

  • Heart

  • Lungs

Abdominopelvic cavity

Below the diaphragm.

Divided into:

Abdominal cavity

  • Stomach

  • Liver

  • Gallbladder

  • Spleen

  • Pancreas

  • Small/large intestines

  • Kidneys

Pelvic cavity

  • Urinary bladder

  • Internal reproductive organs

  • Rectum

🧠 Remember:
Thoracic = chest
Abdominal = belly
Pelvic = pelvis


4. Survival Needs

Humans have 5 basic survival needs:

  1. 💧 Water

  2. 🍎 Food

  3. 🫁 Oxygen

  4. 🌡 Normal body temperature

  5. 🫁 Atmospheric pressure


5. Anatomical Position

The standard position used to describe the human body.

A person is:

  • Standing upright

  • Facing forward

  • Head facing forward

  • Arms at the sides

  • Palms facing forward

  • Feet facing forward


6. Directional Terms

Superior

➡ Above / toward the head

Example: The head is superior to the chest.

Inferior

➡ Below / toward the feet

Example: The stomach is inferior to the heart.

Anterior

➡ Toward the front

Posterior

➡ Toward the back

Medial

➡ Toward the body’s midline

Lateral

➡ Away from the midline

Proximal

➡ Closer to the point where a limb attaches to the body

Example: Shoulder is proximal to the elbow.

Distal

➡ Farther from the point where a limb attaches

Example: Fingers are distal to the elbow.

Superficial

➡ Toward the surface

Deep

➡ Farther inside the body

🧠 Big one to memorize:
Proximal = closer
Distal = farther

9. Abdominal 9 Regions

The abdomen can be divided into 9 regions:

Top row:

1. Right hypochondriac

2. Epigastric

3. Left hypochondriac

Middle row:

4. Right lumbar

5. Umbilical

6. Left lumbar

Bottom row:

7. Right iliac (inguinal)

8. Hypogastric (pubic)

9. Left iliac (inguinal)

🧠 The umbilical region is directly around the belly button.

⸻

10. Body Planes

Sagittal Plane

Divides the body into left and right portions.

Frontal/Coronal Plane

Divides the body into front and back portions.

Transverse Plane

Divides the body into top and bottom portions.

⭐ Question 10:

If the body is cut into a top and bottom half:

➡ Transverse plane

⸻

11. DNA

What is DNA?

DNA = deoxyribonucleic acid

It stores the body’s genetic information.

Where is DNA found?

In a cell’s nucleus.

Shape of DNA:

➡ Double helix

Think: 🪜 twisted ladder.

⸻

DNA Base Pairing

DNA bases pair:

A ↔ T

C ↔ G

Question 21:

Template DNA:

AGGCTAG

Complement:

TCCGATC

🧠 Memorize:

A-T

C-G

⸻

12. Gene Expression

The basic process:

DNA → mRNA → Protein

There are two major steps:

Transcription

DNA → mRNA

📍 Happens in the nucleus.

Translation

mRNA → Protein

📍 Happens at the ribosome.

🧠 Transcription = copy DNA into mRNA

🧠 Translation = turn mRNA into protein

⸻

13. Cell Division

Cells need to divide for:

* Growth

* Repair

* Replacement of old/damaged cells

* Development

⸻

14. Mitosis vs. Meiosis

Mitosis

Produces 2 genetically identical cells.

Used for:

* Growth

* Repair

* Replacing cells

Produces diploid (2n) cells.

Mitosis:

1 division → 2 cells

⸻

Meiosis

Produces 4 genetically different cells.

Used to make:

* Sperm

* Eggs

Produces haploid (n) cells.

Meiosis:

2 divisions → 4 cells

Mitosis

Meiosis

2 cells

4 cells

Genetically identical

Genetically different

Growth/repair

Sex cell production

1 division

2 divisions

Diploid

Haploid

15. Cell Transport

Passive Transport

Does NOT require cellular energy (ATP).

Moves substances from:

High concentration → Low concentration

Examples:

  • Diffusion

  • Osmosis

  • Facilitated diffusion


Active Transport

Requires energy (ATP).

Moves substances from:

Low concentration → High concentration

🧠 Active = ATP

Question 16:

Waste concentration is lower inside the cell than outside, but the cell needs to pump waste out.

➡ Active transport

Because it moves waste from low → high concentration.


16. Endocytosis vs. Exocytosis

Endocytosis

Cell brings substances IN.

➡ Cell membrane surrounds the substance and forms a vesicle.

Exocytosis

Cell sends substances OUT.

➡ Vesicle fuses with the cell membrane and releases its contents.

🧠 ENDO = enter
🧠 EXO = exit


17. Four Types of Tissue

There are 4 major tissue types:

1. Epithelial

➡ Covers and lines surfaces.

Examples:

  • Skin

  • Lining of organs

2. Connective

➡ Supports, connects, and protects.

Examples:

  • Bone

  • Blood

  • Fat

  • Cartilage

3. Muscle

➡ Produces movement.

4. Nervous

➡ Sends electrical signals and communicates.

🧠 E-C-M-N
Epithelial
Connective
Muscle
Nervous


18. Organelles

Nucleus

➡ Contains DNA and controls cell activities.

Ribosomes

➡ Make proteins.

Mitochondria

➡ Produce ATP/usable energy.

Cell membrane

➡ Controls what enters and leaves the cell.

Cytoplasm

➡ Jelly-like material inside the cell.

Vacuole

➡ Stores materials such as water and food.

Lysosome

➡ Breaks down waste and cellular materials.

Endoplasmic Reticulum (ER)

➡ Helps make and transport proteins/lipids.

Golgi Apparatus

➡ Modifies, packages, and ships proteins.


19. Endocrine System

The endocrine system contains glands that produce and release hormones.

Hormones are chemical messengers that help regulate things like:

  • Growth

  • Metabolism

  • Reproduction

  • Blood sugar

  • Stress responses

🧠 Endocrine = hormones


20. Homeostasis

Homeostasis

➡ Maintaining a stable internal environment despite changes outside the body.

Examples:

  • Body temperature

  • Blood sugar

  • Water balance

  • Blood pressure


21. Feedback Loops

Negative Feedback

➡ Reverses/counteracts the original change.

This is the most common type of feedback in the body.

Example:

Body temperature gets too high → sweating occurs → body cools down.

🧠 Negative = brings it back toward normal


Positive Feedback

➡ Amplifies/increases the original change.

Example:

Labor contractions → contractions stimulate more contractions.

🧠 Positive = pushes the process further


22. Stimulus → Receptor → Control Center → Effector

This is how many homeostasis processes work.

Stimulus

A change that needs to be detected.

Receptor

Detects the change.

Control Center

Receives the information and decides what to do.

Effector

Carries out the response.

Example from Question 23:

Morning sunlight → less melatonin → waking up

  • Stimulus: Morning sunlight

  • Receptor: Photoreceptors in the eyes

  • Control center: Brain/hypothalamus

  • Effector: Pineal gland

  • Response: Less melatonin → wakefulness


⭐ ALL 28 REVIEW QUESTIONS — ANSWERS

1. Give a human body example of anatomy and physiology.

Anatomy: The heart has four chambers.
Physiology: The heart pumps blood.

2. Fill in levels of organization.

Cell → Tissue → Organ → Organ System → Organism

3. What are the 2 major sections of the dorsal cavity?

Cranial cavity and vertebral cavity

4. Name a body part/cavity that is anterior to the vertebral cavity.

Ventral cavity

5. Name 2 organs found in the abdominal cavity.

Stomach and liver
(Also: intestines, pancreas, spleen, gallbladder, kidneys.)

6. What are the 5 survival needs?

Water, food, oxygen, normal body temperature, atmospheric pressure

7. Describe anatomical position.

Standing upright, facing forward, arms at sides, palms facing forward, feet facing forward.

8. Which body cavity is directly superior to the abdomen?

Thoracic cavity

9. Name the 9 abdominal regions.

Right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right iliac, hypogastric, left iliac.

10. Top and bottom half = what plane?

Transverse plane

11. Where is genetic information found within a cell?

DNA in the nucleus

12. What is the shape of DNA?

Double helix

13. DNA → mRNA and mRNA → protein?

Transcription → Translation

14. Why do cells divide?

Growth, repair, replacement, and reproduction/development.

15. Give 2 differences between mitosis and meiosis.

Mitosis produces 2 identical cells; meiosis produces 4 genetically different cells.
Mitosis is for growth/repair; meiosis makes sex cells.

16. What type of transport pumps waste from low → high concentration?

Active transport

17. What are the 4 types of tissue?

Epithelial, connective, muscle, nervous

18. What organelle stores food and water?

Vacuole

19. What system contains glands and hormones?

Endocrine system

20. What is proximal to the elbow?

Shoulder

21. Complementary DNA strand for AGGCTAG?

TCCGATC

22. Endocytosis vs. exocytosis?

Endocytosis brings substances into the cell; exocytosis sends substances out.

23. Sunlight → less melatonin:

Stimulus: sunlight
Receptor: eyes/photoreceptors
Control center: brain/hypothalamus
Effector: pineal gland

24. Positive vs. negative feedback?

Positive feedback amplifies a change. Negative feedback reverses/counteracts a change.

25. Transcription vs. translation?

Transcription: DNA → mRNA, nucleus.
Translation: mRNA → protein, ribosome.

26. Name at least 3 abdominal organs.

Stomach, liver, intestines.

27. Compare mitosis and meiosis.

Mitosis: 2 identical cells, 1 division, growth/repair.
Meiosis: 4 different cells, 2 divisions, makes sperm/eggs.

28. Tissue lining the pelvic cavity?

Epithelial tissue — specifically mesothelium (simple squamous epithelium).


🚨 THE STUFF I WOULD MEMORIZE FIRST

If your test is soon, focus heavily on these:

🧠 Directional terms

Superior = above
Inferior = below
Anterior = front
Posterior = back
Medial = toward middle
Lateral = away from middle
Proximal = closer
Distal = farther

🧠 Cavities

Dorsal → cranial + vertebral

Ventral → thoracic + abdominopelvic

🧠 Organization

Cell → Tissue → Organ → Organ System → Organism

🧠 DNA

A-T, C-G
DNA = double helix
DNA → mRNA = transcription
mRNA → protein = translation

🧠 Cell division

Mitosis = 2 identical
Meiosis = 4 different

🧠 Transport

Passive = high → low, no ATP
Active = low → high, ATP

🧠 Tissue

Epithelial, Connective, Muscle, Nervous

🧠 Body regions

Pollex = thumb
Hallux = big toe
Patellar = kneecap
Popliteal = back of knee
Sural = calf
Calcaneal = heel
Plantar = sole
Femoral = thigh
Brachial = upper arm
Antebrachial = forearm
Cervical = neck
Lumbar = lower back