Get introduced to all of the major organ systems of the body. You'll learn some general anatomy (roadmap for your body), and how the organs work to keep you alive! Watch some videos, read some articles, try some flashcards, and then quiz yourself!

No organ quite symbolizes love like the heart. One reason may be that your heart helps you live, by moving ~5 liters (1.3 gallons) of blood through almost 100,000 kilometers (62,000 miles) of blood vessels every single minute! It has to do this all day, everyday, without ever taking a vacation! Now that is true love. Learn about how the heart works, how blood flows through the heart, where the blood goes after it leaves the heart, and what your heart is doing when it makes the sound Lub Dub.

Two circulations in the body

The heart is a double pump

Thermoregulation in the circulatory system

Arteries vs. veins - what's the difference?

Arteries, arterioles, venules, and veins

Circulatory system and the heart

Introductory circulatory system quiz

Intermediate Circulatory System Quiz

Advanced circulatory system quiz

Did you know that your right lung is larger than your left? Thats because the majority of your heart is on the left side of your body, and your left lung is slightly smaller to accommodate it. The lungs take in oxygen and help you breathe out carbon dioxide. Humans have an intricate respiratory system, with hundreds of millions of tiny air sacs called alveoli, where all of the magic happens. These videos will introduce you to the lungs, and show how they help you survive.

How does lung volume change?

Thermoregulation in the lungs

The lungs and pulmonary system

Introductory respiratory system quiz

Intermediate respiratory system quiz

Advanced respiratory system quiz

If you want to learn more about the renal system, then urine the right place! (Pun aside, the kidneys are about more than just making urine). Every thirty minutes, your kidneys filter the entire blood supply in your body. Imagine a dirty pool filled with algae. Placing a filter in this pool will cause the algae to be flushed out, and after a time youll have a clean, crisp blue pool to enjoy. Just like the filter for a pool, our kidneys filter the blood and remove toxic wastes. These paired organs are key to maintaining electrolyte and water homeostasis in your body.

Kidney function and anatomy

Glomerular filtration in the nephron

Changing glomerular filtration rate

Countercurrent multiplication in the kidney

Secondary active transport in the nephron

Introductory urinary system quiz

Roughly 5 L of blood fill your arteries, veins, capillaries, and venules. Whats it good for you ask? It carries oxygen to help your cells carry out respiration in addition to a number of other substances like lipids and hormones throughout the body. In cases of blood loss, such as trauma situations, the physician must be wary of the different blood types. We will explore the intricacies of the hematologic system here.

Life and times of RBCs and platelets

Hemoglobin moves O2 and CO2

Fetal hemoglobin and hematocrit

How do we make blood clots?

Bohr effect vs. Haldane effect

Chances are, youve had a fever or a cough at least once in your life (unless you live in a bubble, in which case you should probably go out more!) Have you ever wondered why your body reacts this way? Your body has a deadly arsenal of weapons against microbial invaders, ranging from bacteria and viruses to protozoans and fungi. We have specialized cells that destroy foreign bodies through mechanisms such as consumption, expulsion, and degradation. You will become acquainted with the interplay of the numerous soldiers in your bodys army and how they keep you healthy!

Role of phagocytes in innate or nonspecific immunity

Types of immune responses: Innate and adaptive. humoral vs. cell-mediated

Professional antigen presenting cells (APC) and MHC II complexes

Review of B cells, CD4+ T cells and CD8+ T cells

Self vs. non-self immunity

How white blood cells move around

Do you live to eat, or eat to live? Folks fall on both sides of this question, but who deny the powerful role that food and water play in our everyday lives. If we were cars, food and water would be the gasoline. Eating keeps us moving, laughing, playing, and learning. The energy from food is carefully extracted through a process of ingestion, digestion, and absorption, and requires one long (very long!) tube with a couple of key organs (liver, pancreas) sprouting off of it. Go ahead and grab a bite to eat before we get started

Meet the gastrointestinal tract!

Small intestine 1: Structure

Small intestine 2: Digestion

Small intestine 3: Absorption

Neurons transmit information to one another through electrochemical signals. They make up the motor nerves that allow you to type an essay, the sensory nerves that let you feel a fluffy dog, and your brain, allowing to remember the content of this module. They have a number of helper cells, ranging from astrocytes, to microglia, to ependymal cells as well. You will come to appreciate the structure and function of neurons and the comrade cells which help to maintain the optimal function of the nervous system.

Introduction to neural cell types

Overview of neuron structure

Overview of neuron function

Correction to sodium-potassium pump video

Electrotonic and action potentials

Saltatory conduction in neurons

Neuronal synapses (chemical)

Types of neurotransmitters

Types of neurotransmitter receptors

Structure of the nervous system

Functions of the nervous system

Peripheral somatosensation

Muscles never sleep (literally). If you have ever taken a breath, you have benefited from the work of the diaphragm, which contracts to create an area of low pressure within your thoracic cavity, allowing air in. How exactly are some weightlifters able to support 717 lbs without breaking anything more than a little sweat? Fun fact: the largest muscle in your body is the gluteus maximus (thats your butt) while the smallest skeletal muscle is the stapedius (it stabilizes the smallest bone, the stapes, which is in your middle ear).

How tropomyosin and troponin regulate muscle contraction

Role of the sarcoplasmic reticulum in muscle cells

Neuromuscular junction, motor end-plate

Type 1 and type 2 muscle fibers

Calcium puts myosin to work

Autonomic vs somatic nervous system

Thermoregulation by muscles

Introductory musculatory system quiz

Advanced musculatory system quiz

Were it not for your skeleton, you and I would be a mere sack of flesh. You will come to appreciate that the bones, together with muscles, are a scaffolding for your body. We will also explore their endocrine function, especially with regards to calcium and phosphate homeostasis. Fun fact: the bone most broken is the clavicle (AKA collar bone).

Skeletal structure and function

Microscopic structure of bone - the Haversian system

Cellular structure of bone

Skeletal endocrine control

Ligaments, tendons, and joints

Glands are special organs that secrete chemical messages called hormones, which seep into the blood - its like putting a tea bag in hot water. As the heart pumps, this blood carries these chemical messages throughout the body, allowing the hormones to interact with specific target cells and organs. Endocrine glands help us to maintain our appetites, grow up, metabolize molecules, concentrate urine,- and oh, so much more! We will examine how these variegated hormones play a role in homeostasis as the body responds to a changing environment.

Endocrine gland hormone review

The hypothalamus and pituitary gland

Hormone
concentration metabolism and negative feedback

Cellular mechanism of hormone action

There is really more than meets the eye with skin. Yes, it does make us look nicer than a bag of bones, muscles, and organs. But it also serves other important purposes which range from guarding the body against infection to sensation to allowing for metabolism of vitamin D. We will explore the structure and function of skin from the macroscopic to the microscopic level in this tutorial.

Meet the skin! (Overview)

What is skin? (Epidermis)

What lies beneath the epidermis? (Dermis and Hypodermis)

Where do our nails and hair come from?

What's in sweat? (Holocrine, Apocrine, Merocrine Glands)

LeBron Asks: Why does sweating cool you down?

Overview of Sensation and Meissner's Corpuscle

Pacinian's Corpuscle and Merkel's Disk

Ruffini's Ending and Hair Follicle Receptor

Thermoregulation by muscles

Your heart pumps roughly 20 L of blood throughout the day to your tissues. The plasma component of blood (not containing blood cells) leaks out through capillaries (the tiniest of blood vessels) and is mostly reabsorbed. However, about 3L of the plasma is left behind in fluid surrounding tissues, and it is the job of the hard-working lymphatic system to bring back this fluid to the circulatory system. The lymphatic system moves fluid in one direction, but without the force of a pump like the heart.

Why we need a lymphatic system

How lymphatic vessels move fluid

The lymphatic system's role in immunity

Lipid and protein transport in the lymphatic system

What is actually in lymph

Our genes are survivors. Even though a person might die, his or her genes will go on to the next generation and then the next generation Some genes are exactly the same as the ones in your great-great-great-grandmother! Yet, with the exception of identical twins, we are all genetically distinct from our family members. Starting with sexual reproduction and then the development of a baby, were going to take a journey that starts with our own microscopic beginning, and ends with a fully formed baby entering the world.

Welcome to the reproductive system

Anatomy of the male reproductive system

Transport of sperm via erection and ejaculation

Basics of egg development

Reproductive cycle graph - Follicular phase

The rest is here:
Khan Academy: Human anatomy and physiology