Anatomy and Physiology is a dynamic textbook for the two-semester human anatomy and physiology course for life science and allied health majors. The book is organized by body system and covers standard scope and sequence requirements. Its lucid text, strategically constructed art, career features, and links to external learning tools address the critical teaching and learning challenges in the course. The web-based version of Anatomy and Physiology also features links to surgical videos, histology, and interactive diagrams.

Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

By the end of this section, you will be able to:Discuss how fertilization occursExplain how the embryo forms from the zygoteDiscuss the role of cleavage and gastrulation in animal development

By the end of this section, you will be able to:List the features that distinguish the kingdom Animalia from other kingdomsExplain the processes of animal reproduction and embryonic developmentDescribe the roles that Hox genes play in development

Once sperm has entered the the oocyte, an ootid is formed. During early stages the ootid will contain male and female pronuclei along with the first and second polar bodies. Fusion of the male and female pronuclei will result in a single diploid nucleus or syngamy. Once syngamy has occurred, the zona pellucida then develops into an imprenetrable layer that prevents polyspermy and so polyploidy. Once the zona pellucida has developed, the ootid is now referred to as a zygote (diploid) and will begin undergoing mitotic divisions via a cleavage process that will begin to give rise to daughter cells called blastomeres. These cleavage divisions will begin to produce a 4-celled embryo and then an 8-celled embryo.

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:

"Placenta development is a critical part of pregnancy in mammals, during which extravillous trophoblast (EVT) cells invade uterine tissue and remodel arteries to establish a placenta–uterus connection. Abnormal EVT cell invasion is associated with complications like preeclampsia and miscarriage emphasizing the need to understand the mechanism of this process. The protein GDF-8 is known to stimulate EVT cell invasion by upregulating the protein MMP2, but it’s unclear whether GDF-11, a related embryonic development regulator, plays a similar role. To learn more, researchers recently treated human EVT cells with GDF-11 in vitro. and found that GDF-11 promoted MMP2 expression. Specifically, GDF-11 exerted this effect via the ALK4/5-SMAD2/3 signaling pathways. In addition, GDF-11 upregulated the protein ID2, which was required for MMP2 upregulation and related EVT cell invasion..."

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

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:

"Lampreys are primitive vertebrates, so research on their genes and proteins can provide unique insights into the evolution of biological processes. LIP, an important immune protein in lampreys, also regulates lamprey growth and development, but the mechanisms of its development- regulating effects are unclear. To learn more, researchers recently examined the function of LIP in a doxycycline (Dox)-activated transgenic zebrafish embryo model. LIP overexpression was toxic to the zebrafish embryos, causing death or developmental malformation by inducing cell death on a broad scale. Specifically, LIP triggered the ferroptosis cell death pathway by upregulating genes such as tfr1a and acsl4a and by causing lipid peroxidation. The LIP-mediated ferroptosis in turn led to pericardial edema in the zebrafish. Direct inhibition and silencing of tfr1a and acsl4a suppressed both ferroptosis and pericardial edema, confirming the roles of these genes in LIP’s developmental effects..."

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

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:

"During epithelial-mesenchymal transition (EMT), epithelial cells lose their polarity and their cell-cell connections to become mobile, in part via transcription factor (TF) activation. EMT and its reverse process, MET, are critical for tissue development in embryos, and EMT enables wound healing during adulthood, but EMT is also how cancer cells metastasize. Live imaging of animal embryos can yield important insights into these key processes. For example, FGF and actomyosin have been found to regulate intercellular adherens junction (AJ) remodeling during EMT in fruit flies. In addition, in zebrafish embryos, the planar cell polarity (PCP) protein pk1 ensures proper EMT of neural crest cells (NCCs), and cadherin 6 ultimately regulates NCC migration..."

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

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:

"Roundup is the most widely used non-selective herbicide, but it’s also one of the most controversial on the market. Much evidence about Roundup's safety is based on toxicity tests that, despite being outdated, are routinely used by regulators and say little about the long-term, sublethal effects of Roundup or its active ingredient glyphosate. Now, a new study has taken a systems biology approach to examine the effects of Roundup on organisms at at the genomic and fitness level. Daphnia are not a Roundup target but are exposed to the herbicide through run-off from farmlands and they are central to aquatic food webs. In the lab, Daphnia were exposed to the regulatory threshold concentration of glyphosate and Roundup. Researchers found that chronic exposure to either chemical had highly detrimental effects including embryonic developmental failure, DNA damage, and signaling interference. Daphnia also showed changes in their microbiome and disruptions in metabolism..."

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

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:

"A fundamental law of genetics states that offspring do not inherit traits from their parents that were acquired in response to environmental conditions. Recent research in the field of epigenetics, however, is turning this principle on its head. Several recent studies have come to the remarkable conclusion that unhealthy diets in males can contribute to the development of metabolic diseases in their offspring. Even when those offspring are raised with healthy diets_._ Now, a study has identified small RNAs as the molecules responsible for the transmission of these disorders. For a long time scientists thought that inheritance of traits only occurred via DNA being passed from parent to offspring. It is now clear, however, that the experiences of one generation can have an effect on the next. When parents have a high-stress lifestyle or an unhealthy diet, for example, chemical modifications can occur on genes that are then passed to their children. This is termed ‘epigenetic inheritance..."

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