Levels of Study

Overview of Anatomical and Physiological Disciplines

Anatomy and physiology are studied at multiple levels, each focusing on different aspects of biological structure and function.

• Histology: Study of tissues, their structure, and organization.

• Cytology: Study of cells, including their function and structure.

• Embryology: Study of early development of cells and tissues, focusing on the formation of organs and systems.

• Regional/Topographical Anatomy: Study of a particular body region, examining relationships between structures.

Characteristics of Life

Defining Features of Living Organisms

All living things share fundamental characteristics that distinguish them from non-living matter.

1. Cellular Composition: Living things are made of cells containing DNA and/or RNA.

2. Hierarchical Organization: Life is organized into levels: atoms → molecules → organelles → cells → tissues → organs → organ systems → organisms.

3. Growth, Development, Reproduction, Evolution: Organisms grow, develop, reproduce, and evolve over time.

4. Sensitivity & Response: Ability to react to environmental stimuli.

5. Metabolism: Includes taking in, storing, and using energy.

Human Survival Needs

Essential Requirements for Life

Humans require specific resources and conditions to survive.

• Water

• Oxygen

• Nutrients (food)

• Stable temperature and pressure

DNA & RNA

Genetic Material and Its Functions

DNA and RNA are nucleic acids responsible for storing and transmitting genetic information.

• RNA base pair: Adenine binds with Uracil in RNA.

• Gene: Segment of DNA that codes for RNA/protein.

• Junk DNA: Non-coding DNA (about 95% of genome).

• Genome: All the DNA (one complete set of chromosomes) in an organism.

• Transcription: Using DNA to make RNA.

• Translation: Using RNA to build proteins.

• DNA Polymerase: Enzyme that builds a new DNA strand.

• RNA Polymerase: Enzyme that reads DNA and makes RNA.

Organelles

Key Cellular Structures and Their Functions

Organelles are specialized structures within cells that perform distinct functions.

• Rough ER: Synthesizes proteins.

• Smooth ER: Synthesizes lipids & carbohydrates; detoxifies toxins.

• Chaperonins: Enzymes that fold proteins into their 3D shape.

• Golgi Apparatus: Modifies, packages, and ships proteins.

Cell Types

Classification of Cells in the Human Body

Cells vary in structure and function, with specialized types for reproduction, transport, and movement.

• Haploid cells: Gametes (sperm & egg), contain half the genetic material.

• Zygote: First cell after fertilization; can become any cell (totipotent).

• Red blood cells: Exception; no nucleus, no DNA.

• Skeletal muscle: Multinucleated cells.

• Cells differ because of gene expression: Different genes are active in different cell types.

Feedback & Homeostasis

Regulation of Internal Environment

Homeostasis maintains stable internal conditions through feedback mechanisms.

• Negative feedback: Brings body back to set point (e.g., body temperature regulation).

• Positive feedback: Enhances a process (e.g., ovulation, blood clotting, childbirth).

Macromolecules

Major Biological Molecules

Macromolecules are large, complex molecules essential for life.

• Polysaccharides: Starch (plants), glycogen (animals), cellulose (plants).

• Proteins: Enzymes, structure, communication, regulation.

• Catabolism: Breakdown of molecules to release energy.

• Anabolism: Building molecules, using energy.

• Animals: Saturated fats.

• Plants: Unsaturated fats.

Organ Systems

Examples of Human Organ Systems

Organ systems are groups of organs that work together to perform complex functions.

• Gonads: Testes (male), ovaries (female).

• Respiratory tract (trachea): Contains ciliated cells for moving mucus and debris.

• Sperm cells: Only human cells with flagella.

Cell Membrane

Structure and Function

The cell membrane controls the movement of substances in and out of cells.

• Phospholipids: Composed of hydrophilic heads and hydrophobic tails, forming a bilayer.

Genetics

Inheritance and Variation

Genetics explains how traits are passed from parents to offspring.

• If offspring shows only one parent's trait, that trait is dominant; otherwise, it is recessive.

• Isotopes: Differ in number of neutrons.

ATP & Cellular Respiration

Energy Production in Cells

ATP is the primary energy currency of the cell, produced through cellular respiration.

• ATP: Energy currency of the cell.

• Cellular respiration: (not 26; corrected value)

• Process involves: Glycolysis (cytoplasm) → Krebs cycle (mitochondria) → Electron Transport Chain (mitochondria).

• If process breaks down improperly, free radicals form.

• Best scavenger of free radicals: Melatonin.

Cell Communication & Development

How Cells Interact and Differentiate

Cells communicate and develop through signaling and programmed processes.

• Induction: One cell releases signals that change neighboring cells.

• Apoptosis: Programmed cell death.

• Neural crest: If delayed, can alter phenotype.

Tissue Types

Major Categories of Tissues

Tissues are groups of similar cells performing specific functions.

• Blood: Connective tissue (liquid matrix = plasma).

• Transitional epithelium: Found in bladder & ureters (not uterus).

Acids, Bases, & pH

Chemical Properties and Biological Importance

pH measures the acidity or basicity of a solution, which is crucial for biological processes.

• pH 3 = acidic

• pH 7 = neutral

• pH 13 = basic

Fun/Extra Exam Notes

Additional Concepts and Examples

• Domesticated fox experiment (Belyaev): Selection based only on behavior.

Additional info: These notes provide a concise overview of foundational concepts in anatomy and physiology, suitable for exam preparation. For deeper understanding, students should refer to textbook chapters and lecture materials.