A reflex arc represents a mechanism by which a physiological function is automatically managed or regulated. Reflex arcs can be found throughout the body, ranging from skeletal muscles to smooth muscle in glands. Reflex arcs are initiated via the excitation or stimulation of specific sensory cells that are directly connected to motor neurons thus enabling motor nerve impulses to be automatically passed on to that particular muscle or gland. Therefore a basic reflex arc consists of sensory cells and their associated nerve fibers, motor nerve fibres and the ultimate muscle or gland.

Overview of refraction and four types of refractive errors: myopia, hypeopia, astigmatism, presbyopia

Refraction of light by the eye and three types of refractive errors: myopia, hyperopia and astigmatism

The ToxMSDT program is providing 6 case study learning modules to toxicology curious students, professionals and the general public.

This Remote Learning Plan was created by Shauna Roberson in collaboration with Nick Ziegler as part of the 2019-20 ESU-NDE Digital Age Pedagogy Project. Educators worked with coaches to create Remote Learning Plans as a result of the COVID-19 pandemic.The attached Remote Learning Plan is designed for a grade 6-9 science students studying human anatomy. Students will: make a claim that is supported by evidence and reasoning on which body system is most important.

This Remote Learning Plan was created by Shauna Roberson in collaboration with Nick Ziegler as part of the 2019-20 ESU-NDE Digital Age Pedagogy Project. Educators worked with coaches to create Remote Learning Plans as a result of the COVID-19 pandemic.The attached Remote Learning Plan is designed for a grade 6-9 science students studying human anatomy. Students will: identify the structure and function of the skeletal system.

Reproductive hormones often have multiple roles and operate via negative feedback systems. The information below will provide the main reproductive hormones in domestic species and their functions.

Development of the reproductive system is a complex process relying on numerous systems and conditions to ensure appropriate structures are formed and the rate of development is maintained within the embryo. There are several important criteria that determine appropriate reproductive system development; genetic sex which determines the sex of the embryo, gonadal sex and phenotypic sex which both determine sexual differentiation. Genetic sex determines gonadal sex which in turn determines phenotypic sex. Sex determination relates to the genetic or environmental process which determines the sex of an individual whilst sexual differentiation represents the development of internal and external genitalia.

Reproduction is the complex set of biological processes that result in the formation of a new organism; it is crucial that we understand how these processes occur normally and have a good grasp of the role of hormones in the reproductive process. Pathology and disease are common within the reproductive system and can not only lead to a sick animal but also to a loss in production. In this section we hope to cover all the main processes in domestic animals, laying a foundation for understanding the associated pathological states.

Human reproduction is complicated and important, and it's going to take a four-part series for us to cover it. Today, we're kicking that off with the female reproductive system, starting with how sex hormones affect oogenesis and ovulation, continuing through how the ovarian and menstrual cycles mature and release oocytes, and creating a comfy uterine environment for a fertilized egg.

Chapters:
Introduction: Human Reproduction
External Female Reproductive Organs
Ovaries Structure & Function
Ovarian Follicles and Oogenesis
The Ovarian Cycle
Fallopian Tubes
The Uterus
The Menstrual Cycle
Review

Our month-long exploration of human reproduction continues with a look at testicular anatomy, the steps of sperm production, and how it’s influenced by gonadotropin and testosterone. Hank also explains how sperm mature, and how they leave the body on a tide of glandular secretions during ejaculation.

Chapters:
Introduction
Testicular Anatomy
Spermiogenesis
How Sperm Mature and Leave the Body
Male Reproductive Glands: Seminal Vesicles, Prostate, Bulbo-urethral
External Male Reproductive Anatomy
Review

After weeks of discussion of human reproduction, today we arrive at the main event: THE SEX. Hank explains the four phases of the human sexual response, how fertilization happens, and how different contraceptive methods work.

Chapters:
Introduction
Four Phases of Human Sexual Response Cycles
Fertilization
Contraceptive Methods
Review

We've reached the grand finale of our four-part series on human reproduction: BABIES! Today Hank walks you through the stages of pregnancy, beginning with how a zygote develops into blastomeres to a morula to a blastocyst, and finally to an embryo and a fetus. He also explains some of the amazing anatomical changes that take place in the mother and the hormonal sequence of events that lead to labor.

Chapters:
Introduction: How Did You Get Here?
Cleavage Stage: Zygote, Blastomeres, Morula, Blastocyst
Implantation
The Placenta
Embryonic Stage
Female Anatomical Changes During Pregnancy
Hormonal Sequences Leading to Labor
Stages of Labor: Dilation, Expulsion, Placental Delivery
Review

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"An international team of biologists has done the seemingly impossible. They’ve revived cell nuclei from a 28,000-year-old frozen woolly mammoth. While the world will have to wait for the first full-blown mammoth resurrection, this could be a big step in that direction. The team’s findings offer researchers hope that ancient DNA, though damaged, could one day be made functional. The research team salvaged the nuclei from the muscle of “Yuka,” a young woolly mammoth well preserved in Siberian permafrost since the last ice age. They then transplanted them into mouse egg cells. This process, called somatic cell nuclear transfer, is the same one used to clone animals like Dolly the sheep. But unlike for Dolly, the development of those nuclei stopped short of cell division. After the transfer, researchers observed filling of the transplanted nuclei with mouse proteins—namely, histone and tubulin— and the formation of a new nucleus-like structure..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

Respiratory epithelium is a type of epithelium which lines both the upper and lower respiratory tracts. It consists of multiple layers of cylindrical epithelium, along with cilia and goblet cells.

The purpose, components, and functions of the respiratory system are presented in this learning through disussion and visualizations. Participants learn about the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli.

Welcome to the first video in our Respiratory System series for Anatomy and Physiology. This video covers the following:
-Functions of the Respiratory System
-Organs that make up the Respiratory System
-What are the upper respiratory tract and lower respiratory tract

Lesson 1 in our Respiratory System series. This is part of our Anatomy and Physiology lecture series.

If this video helps you please be sure to LST -like subscribe and tell your friends. Your support helps us make more videos. For the complete series please visit http://mrfordsclass.net/

Other Free Videos in the Respiratory System series:
-Introduction Respiratory System (16:01): http://youtu.be/Q3v9-EYY19k
-Upper Respiratory Tract (16:02): http://youtu.be/JZotShHbzrw
-Lower Respiratory Tract and Larynx (16:03): http://youtu.be/o3AzfM_4SLs
-Trachea and Bronchi (16:04): http://youtu.be/7WyPKoA0jb4

The previous video we looked at the upper respiratory tract. This starts to look at the lower respiratory tract, specifically the larynx.

Topics covered in this video:
-The organs that make up the Lower Respiratory Tract
-The Larynx
-Parts of the Larynx
-The Epiglottis
-Cricoid Cartilage

Lesson 3 in our Respiratory System series. This is part of our Anatomy and Physiology lecture series.

If this video helps you please be sure to LST -like subscribe and tell your friends. Your support helps us make more videos. For the complete series please visit http://mrfordsclass.net/

Other Free Videos in the Respiratory System series:
-Introduction Respiratory System (16:01): http://youtu.be/Q3v9-EYY19k
-Upper Respiratory Tract (16:02): http://youtu.be/JZotShHbzrw
-Lower Respiratory Tract and Larynx (16:03): http://youtu.be/o3AzfM_4SLs
-Trachea and Bronchi (16:04): http://youtu.be/7WyPKoA0jb4

So we all know that breathing is pretty important, right? Today we're going to talk about how it works, starting with the nameless evolutionary ancestor that we inherited this from, continuing to the mechanics of both simple diffusion and bulk flow, as well as the physiology of breathing, and finishing with the anatomy of both the conducting zone and the respiratory zone of your respiratory system.

Chapters:
Introduction: The First Air-Breathers
Simple Diffusion
Bulk Flow
Mechanics of Breathing
Anatomy of the Conducting Zone
Anatomy of Respiratory Zone
Review
Credits

Can a paper bag really help you when you are hyperventilating? It turns out that it can. In part 2 of our look at your respiratory system, Hank explains how your blood cells exchange oxygen and CO2 to maintain homeostasis. We'll dive into partial pressure gradients, and how they, along with changes in blood temperature, acidity, and CO2 concentrations, change how hemoglobin binds to gases in your blood. (And yes, we'll explain the paper bag thing too!)

Chapters:
Introduction: Hyperventilation
How Blood Cells Exchange Oxygen and CO2
Partial Pressure Gradients
How Hemoglobin Binds to Gases in the Blood
Why Breathing into a Paper Bag Works
Review
Credits