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:Describe epithelial tissuesDiscuss the different types of connective tissues in animalsDescribe three types of muscle tissuesDescribe nervous tissue

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:

"Osteoarthritis is the most common form of joint disease, affecting hundreds of millions of people worldwide. One promising therapeutic target is TGF-β signaling. Studies have shown that blocking this signaling pathway can slow the progression of osteoarthritis. The problem is that TGF-β signaling is also critical for repairing the cartilage cells that are degraded in osteoarthritis. To help separate the bad from the good, researchers recently examined the genetic blueprints that control TGF-β signaling. They discovered a key player in circPhf21a, a type of rare genetic material known as circular RNA. Initially believed to be misshapen RNA, circular RNA is being revealed as an important mediator of disease. In the current study, the team found that overexpression of circPhf21a led to the growth of fewer-than-normal cartilage cells in mice. And in mice with osteoarthritis, levels of circPhf21a were found to be significantly increased..."

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

This animation describes the process of cartilage formation starting with separation from the mesenchymal tissue to the formation of an isogenous cell group via mitosis.

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:

"Osteochondral allograft transplantation is well established for the treatment of large cartilage defects. But despite advancements in this transplantation method, the factors that influence graft survival remain poorly understood—including how long grafts are stored before they’re implanted. In a new study reported in the American Journal of Sports Medicine, researchers examined the effect of storage time on allograft survival in patients undergoing transplantation for symptomatic cartilage defects. Their findings suggest that prioritizing early transplantation could improve the survival rates of osteochondral allografts. The team analyzed data gathered for 132 patients who underwent osteochondral allograft transplantation by a single surgeon with at least 2-year follow-up. The 111 patients who met the study’s inclusion criteria fell into two groups: an early-transplant group who received allografts stored for 19 to 24 days; and a late-transplant group receiving grafts stored for 25 to 28 days..."

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:

"Osteoarthritis is a painful degradation of joint cartilage. Therapies that boost cartilage's limited ability to repair using adipose tissue-derived stem cells (ASCs) have shown promise in cell culture and animal studies, but that success has not carried over to clinical trials. This variability in clinical trials may come down to how the cells are cultured prior to implantation. To test this, a recent study examined a co-culture system combining ASCs taken from the fat pad behind the patella and cartilage cells (chondrocytes). Co-cultured ASCs and chondrocytes had higher expression of cartilage-associated genes than expected, and the effect was larger in cultures with a lower ratio of ASCs to chondrocytes. This gene expression change likely reflects changes in the ASCs and would suggest that the ASCs are starting to make the molecular changes needed to repair damaged cartilage, but increased expression in the chondrocytes, rather than the ASCs, cannot be ruled out without further experiments..."

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:

"Patients with osteoarthritis typically experience progressive cartilage degeneration, joint inflammation, and bony growth around the joints. Treatment of this painful condition remains difficult because the underlying mechanisms aren’t clear, but recent evidence suggests that an increase in aerobic glycolysis, a form of glucose metabolism, may play a role. Aerobic glycolysis is regulated in part by the enzyme hexokinase 2 (HK2), which is upregulated in the joint tissues of patients with osteoarthritis . In addition to participating in glycolysis, HK2 affects cell growth, proliferation, survival, organelle recycling, and death under the influences of various other osteoarthritis-related proteins and pathways. For example, HK2 activity is promoted by the PI3K/Akt pathway, which is activated in osteoarthritis cartilage and HK2 might activate the transcription factor NF-κB to encourage downstream inflammatory processes in joints..."

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