Science 9 Unit I: Respiratory and Circulatory Systems

Study Notes

Module 1 - Respiratory and Circulatory Systems

Nasal Structures: The nose, nasal cavity, and passages serve to warm, moisten, and filter incoming air.
Pharynx: Acts as a dual passageway for air and food.
Airway Structures: Larynx, trachea, bronchi, and bronchioles function as air conduits leading to the lungs.
Alveoli: Small, grape-like air sacs that expand and contract during respiration.
Diaphragm: The muscle responsible for controlling the breathing process.
Blood: Essential for transporting nutrients and oxygen throughout the body.
Blood Vessels: Networks that distribute blood across the body.
Heart: The central organ that pumps blood continuously.
System Interaction: During exercise, the heart rate, blood pressure, and breathing frequency increase to meet oxygen demands, facilitating oxygen delivery to cells and carbon dioxide removal.
Respiratory and Circulatory Diseases:
- Emphysema: Damage to alveolar walls primarily caused by smoking.
- Hypertension: Characterized by elevated blood pressure levels.
- Asthma and Bronchitis: Obstructive diseases impacting the bronchial tubes.
- Atherosclerosis: Build-up of plaque within arterial walls.
System Care Practices:
- Maintain a healthy, balanced diet with low salt, sugar, and fat.
- Ensure 6-8 hours of sleep and uphold proper hygiene.
- Regular physical activity enhances lung capacity and strengthens heart function.
- Avoid tobacco and limit alcohol consumption.

Module 2 - Heredity: Inheritance and Variation

Non-Mendelian Inheritance:
- Incomplete Dominance: Traits exhibit a blend due to one allele not fully masking the other.
- Codominance: Both alleles are equally expressed, e.g., patched-fur cattle.
- Multiple Alleles: More than two alleles govern trait inheritance, e.g., ABO blood types (IA, IB, i).
  - Type AB is a universal recipient.
  - Type O is the universal donor.
Sex Chromosome Basics: Males have XY chromosomes, while females possess XX.
Sex-Linked Traits:
- X-Linked Traits: Affect both genders; examples include hemophilia and color blindness.
- Y-Linked Genes: Affect only males; for instance, hypertrichosis.
Other Trait Categories:
- Sex-Limited Traits: Found on autosomes and expressed exclusively in one gender.
- Sex-Influenced Traits: Present in both genders but more prevalent in one.

Module 3 - Biodiversity and Evolution

Biodiversity Definition: Represents the variety and variability of life forms within a specific area, aiding ecological adaptability.
Population: Defined as a group of individuals of the same species inhabiting a particular area.
Population Density Calculation: Determined by dividing the number of organisms by the size of the area.
Community: Comprises multiple populations interacting in a shared environment.
Limiting Factors: Environmental conditions that restrict population size.
Carrying Capacity: The maximum sustainable population size that an environment can support.
Species Status:
- Threatened: Species experiencing rapid decline, nearing endangered status.
- Endangered: Species with critically reduced populations at risk of extinction.
- Extinction: Refers to the complete disappearance of a species.

Description

Test your knowledge on the key structures and functions of the respiratory and circulatory systems as covered in Science 9, Unit I. This quiz will help you understand how air travels through the body and the role of blood in transportation of materials. Challenge yourself and improve your comprehension of these essential biological systems.