Chapter 1: Human Body Overview

Definitions and Key Concepts

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body’s structural machinery; how the body parts work and carry out their life-sustaining activities.

Levels of Structural Organization

The human body is organized into hierarchical levels, each contributing to the living organism:

• Chemical level: Atoms combine to form molecules.

• Cellular level: Cells are made up of molecules.

• Tissue level: Tissues consist of similar types of cells.

• Organ level: Organs are made up of different types of tissues.

• Organ system level: Organ systems consist of different organs that work together closely.

• Organismal level: The human organism is made up of many organ systems.

Major Organ Systems of the Body

There are 11 organ systems in the human body, each with specific components and functions:

• Integumentary (skin, hair, nails): Protection, temperature regulation.

• Skeletal (bones, joints): Support, movement, blood cell production.

• Muscular (skeletal muscles): Movement, heat production.

• Nervous (brain, spinal cord, nerves): Control, communication.

• Endocrine (glands): Hormone production, regulation.

• Cardiovascular (heart, blood vessels): Transport of nutrients and gases.

• Lymphatic (lymph nodes, vessels): Immunity, fluid balance.

• Respiratory (lungs, airways): Gas exchange.

• Digestive (stomach, intestines): Breakdown and absorption of food.

• Urinary (kidneys, bladder): Waste elimination, water balance.

• Reproductive (ovaries, testes): Production of offspring.

Life Processes and Survival Needs

• Necessary life processes: Maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, growth.

• Survival needs: Nutrients, oxygen, water, normal body temperature, appropriate atmospheric pressure.

Homeostasis

Homeostasis is the maintenance of a stable internal environment despite changes in the external environment. It is vital for proper body function.

• Regulation: Achieved mainly by the nervous and endocrine systems.

• Feedback systems: Consist of three components:

  • Receptor: Detects changes and sends information to the control center.

  • Control center: Determines the set point and appropriate response.

  • Effector: Carries out the response to restore balance.

Negative and Positive Feedback Mechanisms

• Negative feedback: The response reduces or shuts off the original stimulus (e.g., regulation of body temperature, blood glucose levels).

• Positive feedback: The response enhances the original stimulus (e.g., blood clotting, labor contractions).

Examples of Negative Feedback Systems

• Body temperature regulation

• Blood glucose regulation

• Blood pressure regulation

Examples of Positive Feedback Systems

• Blood clotting

• Labor contractions

• Lactation

Practice Questions (Selected)

• Which organ system is NOT required for individual survival? (Reproductive)

• What is the correct hierarchical order from least complex to most complex? (Atoms → molecules → cells → tissues → organs → organ systems → organism)

• What is the study of the human body observed with the naked eye? (Gross anatomy)

Chapter 2: Chemistry Level

Basic Chemistry Concepts

• Matter: Anything that occupies space and has mass. States: solid, liquid, gas.

• Elements: Substances that cannot be broken down by chemical means. 96% of human body: oxygen, carbon, hydrogen, nitrogen.

• Energy: The capacity to do work. Types: kinetic (energy of motion), potential (stored energy).

• Atoms: Smallest unit of an element, composed of protons, neutrons, electrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Compounds and mixtures: Compounds are chemically bonded; mixtures are physically combined.

Chemical Bonds

• Ionic bond: Transfer of electrons between atoms.

• Covalent bond: Sharing of electrons between atoms.

• Hydrogen bond: Weak attraction between a hydrogen atom and another electronegative atom.

• Cation: Positively charged ion.

• Anion: Negatively charged ion.

Types of Chemical Reactions

• Dehydration synthesis: Formation of a larger molecule by removal of water.

• Hydrolysis (decomposition): Breakdown of a molecule by addition of water.

Factors Affecting Rate of Chemical Reactions

• Increase in temperature increases reaction rate.

• Smaller particle size increases reaction rate.

• Higher concentration of reactants increases reaction rate.

• Catalysts (enzymes) increase reaction rate without being consumed.

Inorganic and Organic Compounds

• Inorganic compounds: Water, salts, acids, bases.

• Organic compounds: Carbohydrates, lipids, proteins, nucleic acids.

Water: Properties and Importance

• High heat capacity and vaporization

• Polar molecule; universal solvent

• Lubricates and cushions organs

Acids, Bases, and pH

• Acids: Release hydrogen ions () in solution.

• Bases: Release hydroxyl ions () in solution.

• pH scale: Ranges from 0 to 14; 7 is neutral, below 7 is acidic, above 7 is basic.

Buffers

• Buffer: Resists fluctuations in pH that would be damaging to living tissues.

Biological Molecules

• Carbohydrates: Main energy source; includes monosaccharides, disaccharides, polysaccharides.

• Lipids: Energy storage, insulation, cell membrane structure; includes triglycerides, phospholipids, steroids.

• Proteins: Structure, enzymes, transport, communication; made of amino acids.

• Nucleic acids: DNA and RNA; store and transmit genetic information.

Practice Questions (Selected)

• Which property of water helps maintain a steady internal body temperature? (High heat capacity)

• What is a cation? (Positively charged ion)

• Which of the following is NOT a type of lipid? (Testosterone)

• Which pH value represents the most basic solution? (8.0)

Chapter 3: Cellular Level

Cell Structure and Function

• Main components of animal cell: Plasma membrane, cytoplasm, nucleus.

• Plasma membrane: Phospholipid bilayer with embedded proteins; controls entry and exit of substances.

• Membrane proteins: Transport, receptors, enzymes, cell recognition, attachment.

Transport Across Plasma Membrane

• Passive transport: No energy required; includes diffusion, osmosis, facilitated diffusion.

• Active transport: Requires energy (ATP); includes pumps, vesicular transport.

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Isotonic solution: No net movement of water.

• Hypotonic solution: Water enters cell; cell may swell.

• Hypertonic solution: Water leaves cell; cell may shrink.

Vesicular Transport

• Endocytosis: Cell takes in material by forming vesicles.

• Exocytosis: Cell expels material by vesicle fusion with membrane.

• Types of endocytosis: Phagocytosis (cell eating), pinocytosis (cell drinking), receptor-mediated endocytosis (specific uptake).

Cell Organelles and Functions

• Rough ER: Protein synthesis.

• Smooth ER: Lipid synthesis, detoxification.

• Golgi complex: Modifies, sorts, packages proteins.

• Mitochondria: ATP production.

• Lysosomes: Digestion of cellular debris.

• Cytoskeleton: Cell shape, movement; includes microfilaments, intermediate filaments, microtubules.

• Microvilli: Increase surface area for absorption.

• Cilia: Move substances across cell surface.

Protein Synthesis

• Transcription: DNA is copied into mRNA in the nucleus.

• Translation: mRNA is decoded to build protein in the cytoplasm.

• Types of RNA: mRNA, tRNA, rRNA.

• Codon: Sequence of three nucleotides on mRNA that codes for an amino acid.

Cell Division

• Purpose: Growth, repair, reproduction.

• Phases of cell cycle: Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase), cytokinesis.

• Apoptosis: Programmed cell death; important for development and homeostasis.

Practice Questions (Selected)

• A phospholipid molecule is usually: (Partially hydrophilic and partially hydrophobic)

• Which of the following is NOT an example of endocytosis? (Osmosis)

• What is the function of cilia? (Move substances across cell surface)

Additional info:

• Some content was expanded for clarity and completeness, including definitions and examples.

• Tables were not present in the original material; key comparisons and classifications were described in text.