Anatomy & Physiology: Circulatory, Respiratory, and Digestive Systems

Structure and Function

The structure of organs and tissues in the circulatory, respiratory, and digestive systems is closely related to their functions, enabling efficient transport, exchange, and processing of substances.

• Circulatory System: Composed of the heart, blood vessels, and blood; its structure allows for the transport of oxygen, nutrients, and wastes throughout the body.

• Respiratory System: Includes lungs and airways; specialized for gas exchange, providing oxygen and removing carbon dioxide.

• Digestive System: Consists of organs such as the stomach and intestines; structured for breaking down food and absorbing nutrients.

• Example: The thin walls of alveoli in the lungs facilitate rapid gas exchange.

Movement of Substances

• Oxygen: Enters via the respiratory system, transported by blood to tissues.

• Carbon Dioxide: Produced by cells, carried by blood to lungs for exhalation.

• Nutrients: Absorbed in the digestive system, distributed by the circulatory system.

• Wastes: Removed via circulatory and excretory systems.

Homeostasis

• pH Regulation: Buffers in blood maintain pH; lungs and kidneys adjust CO2 and H+ levels.

• Temperature: Blood flow adjusts to regulate heat distribution.

• Gas Levels: Respiratory rate changes to balance O2 and CO2.

• Nutrients: Digestive and circulatory systems ensure proper nutrient levels.

Integration of Systems

• These systems work together to support cellular respiration and maintain balance.

• Disruptions (disease, environmental changes) can affect homeostasis.

Genetics

Alleles and Inheritance

• Allele: Variant form of a gene; inherited from parents.

• Dominant/Recessive: Dominant alleles mask recessive ones in heterozygotes.

• Punnett Squares: Used to predict genetic outcomes (monohybrid and dihybrid crosses).

• Genotype vs. Phenotype: Genotype is genetic makeup; phenotype is observable traits.

• Homozygous: Two identical alleles; Heterozygous: Two different alleles.

Complex Patterns of Inheritance

• Incomplete Dominance: Heterozygote shows intermediate phenotype.

• Codominance: Both alleles are fully expressed.

• Multiple Alleles: More than two alleles for a gene (e.g., ABO blood types).

• Polygenic Inheritance: Multiple genes influence a trait.

Mendelian Principles

• Law of Segregation: Alleles separate during gamete formation.

• Law of Independent Assortment: Genes for different traits assort independently.

• Law of Dominance: Dominant alleles mask recessive ones.

• Mendel's Pea Plant Experiments: Foundation of modern genetics.

Blood Type Genetics

• ABO System: Controlled by three alleles (A, B, O).

• Rh Factor: Positive or negative, determined by separate gene.

• Genotypes: AA, AO, BB, BO, AB, OO; Rh+ or Rh-.

Sex-linked Traits and Disorders

• Sex-linked Traits: Located on X or Y chromosomes; more common in males.

• Genetic Disorders: Can be dominant, recessive, or due to nondisjunction (e.g., Down syndrome).

• Pedigrees: Diagrams showing inheritance patterns.

Meiosis

Comparison with Mitosis

• Mitosis: Produces two identical diploid cells.

• Meiosis: Produces four genetically unique haploid cells (gametes).

• Cells: Meiosis occurs in germ cells; mitosis in somatic cells.

Genetic Variation

• Crossing Over: Exchange of genetic material during Prophase I.

• Independent Assortment: Random distribution of chromosomes.

• Importance: Increases genetic diversity.

Relation to Mendel's Laws

• Meiosis explains segregation and independent assortment of alleles.

DNA Structure and Protein Synthesis

Major Discoveries

• Franklin: X-ray diffraction images revealed DNA's helical structure.

• Watson & Crick: Proposed double helix model.

• Chargaff: Discovered base pairing rules.

DNA Structure

• Nucleotide: Composed of sugar, phosphate, and nitrogenous base.

• Chargaff's Rules: A=T, C=G.

• Double Helix: Two strands held together by hydrogen bonds.

DNA Replication

• Helicase: Unwinds DNA.

• DNA Polymerase: Synthesizes new strands.

• Result: Two identical DNA molecules.

Central Dogma of Biology

• Information flows from DNA → RNA → Protein.

Transcription and Translation

• Transcription: DNA is copied into mRNA in the nucleus; RNA polymerase is key enzyme.

• Translation: mRNA is decoded into protein at the ribosome.

• Types of RNA: mRNA (messenger), tRNA (transfer), rRNA (ribosomal).

• RNA Processing: Introns removed, exons spliced.

DNA vs. RNA

• DNA: Double-stranded, deoxyribose, thymine.

• RNA: Single-stranded, ribose, uracil.

Mutations

• Gene Mutations: Substitution, insertion, deletion.

• Chromosomal Mutations: Deletion, duplication, inversion, translocation.

• Effects: Can be harmful, neutral, or beneficial.

• Relation to Cancer: Mutations can lead to uncontrolled cell growth.

Gene Expression Regulation

• Lac Operon: Example of gene regulation in prokaryotes.

Evolution

Darwin's Theory

• Natural Selection: Organisms with advantageous traits survive and reproduce.

• Influences: Lamarck (inheritance of acquired traits), Malthus (population limits), Hutton & Lyell (geological time), Wallace (independent theory).

• Lamarck vs. Darwin: Lamarck proposed acquired traits; Darwin emphasized inherited variation.

Adaptations and Evidence

• Adaptations: Traits like mimicry and camouflage evolved over time.

• Evidence: Fossils, anatomy, molecular biology, biogeography.

Speciation and Isolation

• Speciation: Formation of new species.

• Isolation Types: Geographic, temporal, behavioral.

Types of Selection

• Stabilizing: Favors average traits.

• Disruptive: Favors extreme traits.

• Directional: Favors one extreme.

Population Genetics

• Variation: Sexual reproduction increases variation.

• Allele Frequency: Changes over time indicate evolution.

• Hardy-Weinberg Equilibrium: Used to determine if evolution is occurring.

• Bottleneck and Founder Effect: Reduce genetic diversity in small populations.

Phylogeny and Classification

• Phylogenetic Tree: Diagram showing evolutionary relationships.

• Classification: Three domains (Bacteria, Archaea, Eukarya), six kingdoms.

• Binomial Nomenclature: Scientific naming system.

Ecology

Levels of Organization

• Organism → Population → Community → Ecosystem → Biome → Biosphere

Energy Flow

• Food Chains & Webs: Show energy transfer.

• Ecological Pyramids: Represent biomass, energy, or numbers.

• 10% Rule: Only 10% of energy is transferred to next trophic level.

• Trophic Levels: Producers, consumers, decomposers.

Biogeochemical Cycles

• Water, Nitrogen, Carbon Cycles: Movement of elements through environment.

• Decomposers: Recycle nutrients.

Limiting Factors and Productivity

• Limiting Nutrient: Restricts productivity.

• Primary Productivity: Rate of biomass production.

• Algal Blooms: Result from excess nutrients.

Abiotic vs. Biotic Factors

• Abiotic: Non-living (temperature, water).

• Biotic: Living (plants, animals).

Species Niche and Community Interactions

• Niche: Role of species in ecosystem.

• Competitive Exclusion Principle: No two species can occupy same niche.

• Interactions: Competition, predation, symbiosis (parasitism, mutualism, commensalism).

Population Ecology

• Density: Number of individuals per area.

• Immigration/Emigration: Movement in/out of population.

• Birth/Death Rates: Affect population size.

• Growth Curves: Logistic (S-shaped), Exponential (J-shaped).

• Carrying Capacity: Maximum population size environment can support.

• Density-dependent Factors: Competition, disease, predation.

• Density-independent Factors: Weather, natural disasters.

Predator-Prey Regulation

• Predators control prey populations; prey availability affects predator numbers.

Environmental Issues and Human Impact

• Global Warming, Acid Rain, Ozone Depletion: Major environmental concerns.

• CHIPPO: Climate Change, Habitat destruction, Invasive Species, Pollution, Population, Overharvesting.

• Biomagnification: Increase in toxin concentration up food chain.

• Bioaccumulation: Build-up of substances in organisms.

Sample Table: Types of Selection

Sample Equation: Hardy-Weinberg Equilibrium

Where: p = frequency of dominant allele, q = frequency of recessive allele