A new session of each course opens each month, allowing you to enroll whenever your busy schedule permits!
How does it work? Once a session starts, two lessons will be released each week, for the six-week duration of your course. You will have access to all previously released lessons until the course ends.
Keep in mind that the interactive discussion area for each lesson automatically closes 2 weeks after each lesson is released, so you’re encouraged to complete each lesson within two weeks of its release.
The Final Exam will be released on the same day as the last lesson. Once the Final Exam has been released, you will have 2 weeks plus 10 days to complete the Final and finish any remaining lessons in your course. No further extensions can be provided beyond these 10 days.
Lesson 01 - The Four Types of Tissues
In our first lesson, you'll learn about the four major types of tissues—epithelial, connective, muscle, and nervous tissue. We'll go over their major characteristics, how they're named, their functions, and where they're located. You'll discover some hints on identifying some specific tissues with a microscope, and I'll explain why every organ in your body contains all four major types of tissues.
Lesson 02 - Cutaneous Sensation
In this lesson, we'll explore the topic of sensation as you learn about the sensations of touch, pressure, temperature, and pain. You'll discover the differences between free nerve endings, Merkel disks, Meissner corpuscles, root hair plexuses, and Pacinian corpuscles. We'll also talk about sensory adaptation and referred pain, and you'll learn where in the brain messages from sensory receptors end up. We'll end the lesson with a discussion of three disorders of cutaneous sensation—tactile defensiveness, congenital insensitivity to pain, and peripheral neuropathy.
Lesson 03 - The Senses of Proprioception and Equilibrium
Today, you'll learn about sensory receptors (muscle spindles, Golgi tendon organs, and joint proprioceptors) that tell your brain how much tension is in your muscles and the position of your body parts. You'll learn why accurate information from these receptors is so important and how the brain uses their information to help you plan your movements. We'll also discuss the sense of equilibrium—that sense that lets you know if you're upright and if you're in danger of falling. You'll study the structures of the vestibular system and learn how they contribute to both static and dynamic equilibrium. I'll summarize this lesson by telling you what happens when a person experiences proprioceptive or vestibular dysfunction.
Lesson 04 - The Sense of Vision
Now it's time to learn about the physics of light and color and find out how light is bent and focused. Today, you'll learn about the composition of the eyes, including their three coverings and the structures inside the eyeballs. We'll talk about special sensory receptors called rod and cones, and how information they receive is sent to the brain and analyzed. We'll end this lesson with a discussion about three common eye disorders—glaucoma, cataracts, and macular degeneration.
Lesson 05 - The Sense of Hearing
In this lesson, you'll discover the physics of sound. You'll learn why sounds differ in pitch and loudness, and you'll find out about a quality of sound called color. We'll then talk about the different structures that make up the outer ear, middle ear, and inner ear. You'll learn what happens when sound waves enter the ear and how information from the ear travels to the brain for analysis. We'll end this lesson with a discussion of hearing loss.
Lesson 06 - The Senses of Smell and Taste
Today, we'll finish up our study of the senses with a discussion on the senses of smell and taste. You’ll learn about the structures that respond to chemicals of smell and taste, and how the sensations of smell and taste are perceived in the brain. We’ll also talk about disorders of both of these senses, and you’ll have an opportunity to perform a fun experiment to test the importance of smell to the perception of flavor.
Lesson 07 - Cellular Metabolism
In this lesson, we'll go over the fascinating topic of cellular metabolism—the chemical reactions that occur in your body’s cells. We’ll review the important concepts of homeostasis and negative feedback, and you’ll learn that homeostasis is maintained by thousands of chemical reactions that occur every second. Those chemical reactions either build larger molecules from smaller ones or break apart larger molecules into smaller ones, so we'll discuss what happens in those two major types of reactions. You’ll also learn about the capture and storage of energy, the role of enzymes in metabolic pathways, and disorders of cellular metabolism.
Lesson 08 - Water, Acids, Bases, and Salts
In today's lesson, we'll continue our study of important chemicals in the human body. We'll start out by reviewing the differences between atoms and ions, and the differences between ionic and covalent bonds. We'll then move on to a study of water, its unique properties, and its important functions. You'll learn that water breaks apart molecules called electrolytes, and that the three major types of electrolytes include acids, bases, and salts. We'll discuss the pH scale—a way to measure the degree of acidity in a substance, and you'll learn about the conditions called acidosis and alkalosis. We'll finish up the lesson with a discussion about imbalances of three important ions—sodium, potassium, and calcium.
Lesson 09 - Prenatal Development
Today, we'll go over the wonders of prenatal development. You’ll learn about the roles both men and women play in the creation of the zygote—the very first cell that starts a new human life. We’ll then follow that new creature through the amazing changes that happen during the first eight weeks after fertilization (the embryonic period). We’ll also discuss significant events that occur during the rest of the pregnancy (the fetal period). At the end of this lesson, I’ll tell you about some common causes of both male and female infertility.
Lesson 10 - Pregnancy, Childbirth, the Postpartum Period, and Breastfeeding
In this lesson, you'll learn about pregnancy from the mother's point of view. We'll start with a discussion about the placenta, and then we'll talk about the way pregnancy affects the mother's different organ systems. We'll also discuss the events of childbirth and what a mother experiences during the postpartum period. Many women choose to breastfeed (lactate), so I'll also tell you how breasts prepare for lactation, how milk is produced, and how it's secreted. We'll end this lesson with a discussion of a complication of pregnancy called gestational diabetes.
Lesson 11 - The Neonatal Period, Infancy, and Childhood
In today's lesson, we'll focus on the neonatal period, infancy, and childhood. We'll start with a discussion of normal circulation of blood in children and adults and compare that to circulation in the fetus. That's so you can understand the big changes that occur in the heart, blood vessels, and lungs as soon as a baby takes his first breath. We'll then talk about other changes in the first four weeks after birth (the neonatal period), and we'll move on to a discussion of reflexes and brain maturation during the first year and significant changes that occur during childhood. At the end of this lesson, you'll learn about a common developmental disorder in children called cerebral palsy.
Lesson 12 - Puberty, Adulthood, and Old Age
In our final lesson, we'll go over puberty, adulthood, and old age. You'll learn how hormones work during puberty and what physical changes occur during that time. We'll also discuss changes that occur during young adulthood and middle age and spend some time on menopause. I devote a chapter to the topic of senescence—the process of aging during the years 65 and over. In that chapter, you'll learn several reasons why getting older causes age-related changes. We'll end this lesson with a discussion of ways to slow down the aging process.