Muscle Contraction, Agonists, and Antagonists
Agonists, Antagonists, and Synergists
Agonists: These are the main muscles responsible for movement. They produce most of the force required for a particular action.
Antagonists: These muscles oppose the primary mover (agonist). They play a protective role and help control the movement of the agonist.
Synergists: These muscles assist the primary movers.
Muscle Contraction
Muscle contraction occurs when tension is applied to the bones via the tendons, resulting in torque on a joint.
Types of Muscle Actions
- Isometric:
Cell Biology: Regulation, Organelles, Division, and Photosynthesis
Cellular Regulation and Maintenance
Regulation of pH is essential for maintaining life. It requires that cellular and organic fluids stay within certain limits. Otherwise, structural changes in biomolecules and alterations in chemical reactions may occur. In aqueous solutions, living beings use weak acid-base buffer systems and their conjugates. Types include:
- Inorganic bicarbonate: HCO3– + H+ ⇌ H2CO3 ⇌ CO2 + H2O
- Phosphate: HPO42- + H+ ⇌ H2PO4–
Cellular Organelles and Their Functions
Ribosomes:
Read MoreDNA Replication: Mechanisms, Enzymes, and E. Coli Process
DNA Replication Fundamentals
The organism has the ability to create exact copies of itself, based on a template. This was discovered when it was clear that DNA somehow acts to serve as a template in replication and transcription of genetic information. Each of the two strands are complementary to each other, following these rules:
- DNA replication is semiconservative: Each DNA strand is the template for the synthesis of a new chain. The result is two new DNA molecules, each with a new chain and an
Cell Cycle, DNA Replication, and Mitosis Explained
The Cell Cycle
The cell cycle involves:
- Doubling of hereditary material, which is then equally divided between daughter cells.
- Division of the cytoplasm into two.
The cell cycle is a series of changes a cell undergoes from one division to the next, ultimately resulting in two daughter cells.
Cell Cycle Control
Cell cycle control occurs at the molecular level, regulated by cytoplasmic proteins, including cyclins and kinases. Checkpoints determine if the cell receives a signal to divide; if not, it enters
Read MoreEvolutionary Evidence and Human Origins
Evidence for Evolution
Testing Status
Evolutionary evidence is based on observations of intermediate species. For example, the platypus exhibits characteristics of both mammals and reptiles.
Biological Tests
Species differ across geographical areas, with greater differences observed in more isolated regions. An example is the 13 species of finches found in the Galapagos Islands.
Paleontological Testing
Comparing fossils with present-day animals reveals differences and similarities between past and current
Read MoreSensory Receptors and the Human Body Systems
Sensory Receptors
Structures formed by specialized nerve cells to capture and transform stimuli into nerve impulses.
According to Stimuli Captured
- Chemoreceptors: Sensitive to chemicals.
- Mechanoreceptors: Sensitive to mechanical stimuli.
- Photoreceptors: Light-sensitive.
- Thermoreceptors: Sensitive to temperature variations.
- Nociceptors: Responsible for the sensation of pain.
Depending on Their Position
- Internal receptors: Responsible for collecting information inside the body.
- External receptors: Responsible