Nervous and Endocrine Systems in Vertebrates
Nervous System
The nervous system collects various stimuli from both inside and outside the body through specialized neurons organized in receptors. External stimuli are detected by exteroceptors, while internal stimuli are detected by interoceptors. This information is transmitted to the central nervous system (CNS), which processes the information and generates a response. Organs that execute commands from the CNS are called effectors.
Invertebrate Nervous Systems
- Nerve Net: Found in primitive animals
Human Body Functions and Coordination
Interaction and Stimuli
The interaction function allows us to perceive internal and external changes (stimuli), interpret them, and generate coordinated responses for survival.
Stimuli and Receptors
A stimulus is a physical or chemical change that triggers a response. Specialized cells called receptors perceive stimuli and send information to coordination centers.
Types of Receptors
- Internal receptors: Perceive changes inside the body (e.g., blood sugar levels).
- External/Sensory receptors: Perceive external
Cellular Biology: From Nucleus to Apoptosis
The Nucleus
Structure
- Envelope: A double membrane with nuclear pores enabling communication between nucleus and cytoplasm.
- Nucleoplasm: The internal environment containing DNA, RNA, proteins, and the nucleolus.
- Cellular Matrix: A protein network organizing chromatin. The nuclear lamina, made of intermediate filaments, contacts the inner membrane.
- Nucleolus: Concentrates ribosomal genes encoding ribosomal RNA.
Chromatin and Chromosomes
During interphase, chromatin forms nucleosome filaments or 30 nm fibers.
Read MoreInfection Control and Prevention in Dental Practices
Infection Control in Dental Practices
Contamination and Infection
The mouth cavity can be contaminated by various germs. Infection occurs when the body is invaded by an external agent capable of causing disease.
Routes of Transmission
- Direct Contact: Occurs through contact with organic fluids (blood, saliva) that directly penetrate the body via oronasopharyngeal routes, skin wounds, conjunctiva, or other mucous membranes.
- Indirect Contact (Fomites): Occurs through contact with contaminated instruments
Cellular Respiration: Glycolysis, Krebs Cycle, and Chemiosmosis
Glycolysis
Glycolysis converts glucose into pyruvate through a sequence of 10 enzyme-catalyzed reactions. It consists of two main stages:
- Preparatory Stage: Glucose is phosphorylated, consuming two ATP molecules, and ultimately producing two molecules of glyceraldehyde-3-phosphate. The phosphorylation of glucose prevents it from leaving the cell.
- Second Stage: The two glyceraldehyde-3-phosphate molecules are oxidized by NAD+ and converted to pyruvate, generating four ATP molecules. The net energy
Soil Contamination and Waste Management
Soil Contamination and Its Effects
Contaminated Soil and Diseases
Soil contamination from septic tanks, treated water, and sewage systems poses a serious health risk. Contaminated feces can infect the soil and contaminate food and water sources. It’s crucial to follow basic hygiene rules, like washing hands before eating. Governments must provide clean water, efficient sewage collection, and proper waste disposal.
Diseases Associated with Contaminated Soil
- Tetanus: Caused by the bacterium Clostridium