Invertebrate Excretory and Digestive Systems
Excretory Organs in Invertebrates
1. Protonephridia
Characteristics of flatworms. They are highly branched tubes whose inner end terminates in a cell with flagella, called a flame cell, and the outer end terminates in an excretory pore. The flame cells are among the intercellular fluids.
2. Metanephridia
Typical of annelids and mollusks. The metanephridia are long tubes with an inner end shaped like a funnel (nephrostome) having cilia. The coelomic cavity communicates with the anterior segment. The
Read MoreUnderstanding Health, Illness, and Immunity
Concept of Health
World Health Organization (WHO) Definition of Health: “The state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.”
Factors Influencing Health
- Lifestyle: Diet, physical exercise, stress level, consumption of alcohol, drugs, tobacco, etc.
- Environment: Pollution, radiation, toxic substances, pathogenic microorganisms.
- Genetic Factors: Genetic predisposition (resistance to some diseases), age (health often deteriorates with age).
- Healthcare
Endothermy, Ecosystems, and Nutrient Cycling: A Deep Dive
Endothermy and its Ecological Impact
Pike and Opah exhibit unique physiological adaptations. The Opah possesses dark red aerobic pectoral musculature, enabling continuous swimming and pectoral fin oscillation. Heat-conserving retia mirabilia, located inside the gills, act as countercurrent heat exchangers, transferring heat from afferent to efferent blood vessels. Fish also utilize countercurrent exchange to maximize oxygen uptake. Fish gills have filaments with protrusions called lamellae, which
Read MoreEnvironmental Health Midterm: Key Topics and Concepts
Environmental Health
Midterm Study Guide Topics
Week 1: Introduction to Environmental Health
Healthy People Environmental Health Objectives:
- Outdoor air quality
- Water quality
- Toxics and waste
- Healthy homes and healthy communities
- Infrastructure and surveillance
- Global environmental health
Environmental Health Threats:
- Trash that fouls our beaches
- Hazardous wastes (including radioactive wastes) leaching from disposal sites
- Continuing episodes of air pollution
- Exposures to toxic chemicals
- Destruction of the land
Neutrophils and Macrophages: Defenders of the Body
Defensive Properties of Neutrophils and Macrophages
- Mainly responsible for the destruction of bacteria, viruses, and pests.
- Neutrophils: Mature cells that destroy bacteria, even in the circulating blood.
- Macrophages: Initially monocytes in the blood that migrate to the tissues and develop into macrophages (growth and lysosomes).
Diapedesis and Movement of Neutrophils and Macrophages
- Neutrophils and macrophages enter the tissue spaces by diapedesis.
- They move through the tissues.
- Amoeboid movement: Tissues
Human Embryonic Development: The Third Week
The Third Week of Pregnancy
Amenorrhea and Pregnancy Confirmation
Amenorrhea is not a definitive pregnancy test and can be caused by various factors. Implantation bleeding can occur. Pregnancy is typically diagnosed around the third or fourth week after a missed period, sometimes even later. By the end of the third week, some clinical changes may appear, such as breast tension and swelling, constipation, frequent urination, and nausea/vomiting. These signs are not always consistent but hold significant
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