Anatomy and Physiology 1 Study Guide

Anatomy and Physiology 1 (BSC2085) Unit 1 Study Guide

Chapters 1, 2 & 3

1. Basic Definitions and Concepts

Anatomy: The study of the structure of body parts.
Physiology: The study of how those body parts function.
The human body is organized into eleven major systems:
- Skeletal
- Endocrine
- Reproductive
- Digestive
- Cardiovascular
- Lymphatic/Immune
- Muscular
- Nervous
- Integumentary
- Urinary
- Respiratory

2. Life Processes and Homeostasis

Life Processes: Key functions that distinguish living from non-living
- Responsiveness: The body's ability to detect and respond to stimuli.
- Metabolism: The sum of all chemical reactions in the body.
- Differentiation: The process where unspecialized cells become specialized.
- Reproduction: The formation of new cells or a new individual.
Homeostasis: A state of equilibrium (balance) in the body's internal environment, maintained by the body's regulatory processes.
Aging: Associated with a progressive decline in the body's ability to maintain homeostasis.

3. Feedback Systems

Homeostasis is maintained through feedback loops.
- Negative Feedback: The most common type; the response reverses or reduces the original stimulus to bring conditions back to normal (e.g., body temperature regulation, blood sugar control).
- Positive Feedback: The response intensifies or reinforces the original stimulus, driving a process to completion. Used for processes that are not continuous (e.g., childbirth contractions, blood clotting).

4. Body Orientation and Membranes

Anatomical Position: The standard reference point—standing erect, facing forward, arms at sides, palms forward.
Body Position Terms:
- Supine: Lying face up.
- Prone: Lying face down.
Directional Terms: In humans, anterior (front) and ventral (belly side) mean the same thing.
Serous Membranes: Thin, double-layered membranes that line body cavities and cover organs, reducing friction.
- Examples include:
- Pleura: Covers the lungs.
- Pericardium: Covers the heart.
- Peritoneum: Covers abdominal organs.

5. Basic Chemistry for Biology

Essential Elements: Over 95% of the body's mass is made of oxygen, carbon, hydrogen, and nitrogen.
Atoms and Elements:
- The smallest unit of an element is an atom.
- The number of protons defines an element and gives it its distinctive properties.
Molecules vs. Compounds:
- Molecule: Two or more atoms bonded together (e.g., $(H2, O2, H_2O)$ ).
- Compound: A molecule made of atoms from different elements (e.g., $(H2O)$ ). Thus, $(H2)$ is a molecule but not a compound.

6. Ionic Bonds, Covalent Bonds, and Hydrogen Bonds

Ionic Bonds: Form when an atom donates an electron to another atom, creating oppositely charged ions.
- A salt is formed of crystals of cations and anions held together by ionic bonds.
Covalent Bonds: Atoms share electrons; these bonds are stronger than ionic bonds.
Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (like oxygen or nitrogen).
- Crucial for properties of water, DNA structure, and protein structures.

7. Chemical Reactions and Energy

Energy Types:
- Potential Energy: Stored energy (e.g., energy in a chemical bond, energy in snow on a roof).
- Kinetic Energy: Energy of motion.
Reaction Types:
- Synthesis Reaction (Anabolic): $A + B ightarrow AB$ . Builds things up (e.g., building bone mineral crystals).
- Decomposition Reaction (Catabolic): $AB ightarrow A + B$ . Breaks things down.
- Exchange Reaction: $AB + CD ightarrow AD + CB$ . Components are swapped.
Energy in Reactions:
- Exergonic Reactions: Release energy.
- Endergonic Reactions: Absorb energy.

8. Organic Compounds and Mixtures

Organic Compounds: Contain carbon and hydrogen (e.g., methane $(CH4)$ , glucose $(C6H{12}O6)$ ).
Mixtures:
- Solution: A mixture where particles are tiny and do not settle out (e.g., salt water).
- Suspension: A mixture where particles are large, may settle out, and can scatter light (e.g., pancake batter with sinking chocolate chips, blood).
Salts, Acids, and Bases:
- A salt is a substance that dissociates into cations and anions (neither $(H^+)$ nor $(OH^-)$ ) in solution (e.g., $KCl ightarrow K^+ + Cl^-$ ).

9. Biological Macromolecules

Carbohydrates:
- Glucose is a hexose monosaccharide and is the primary fuel for brain cells.
Proteins:
- Building blocks are amino acids, which contain an amino functional group.
Nucleic Acids (DNA/RNA):
- Monomers are nucleotides, which contain a pentose sugar (deoxyribose or ribose).
- In DNA, two nucleotide strands form a double helix.
Lipids:
- Phospholipid: Main component of the plasma membrane; is amphipathic, meaning it has both polar and nonpolar regions.

10. Cell Structure (Organelles)

The three main parts of a cell are:
1. Plasma Membrane: The flexible, sturdy outer boundary.
2. Cytoplasm: All cellular contents between the membrane and nucleus (includes cytosol and organelles).
3. Nucleus: The large organelle that houses the cell's genes, arranged on chromosomes.
Lysosome: Digest worn-out organelles and foreign material using powerful enzymes.
Peroxisome: Oxidizes (breaks down) organic substances like fatty acids using oxygen.
Ribosome: The site of protein synthesis.
Mitochondria: The "powerhouse" that produces most of the cell's ATP.

11. Plasma Membrane Structure & Function

Structure: Fluid mosaic of lipids and proteins.
- Integral (Transmembrane) Proteins: Span the entire lipid bilayer.
- Peripheral Proteins: Attached to the inner or outer surface but not embedded in it.
- Cholesterol: A lipid that stabilizes the membrane and reduces its fluidity.
Functions of Membrane Proteins:
- Act as ion channels, carriers, receptors, enzymes, linkers, and cell identity markers.

12. Membrane Transport

Permeability: The membrane is selectively permeable.
- Freely Permeable: Small, nonpolar, uncharged molecules (e.g., $O2, CO2$ ).
- Not Freely Permeable: Ions, large polar molecules (require protein channels, carriers, or vesicles).
Gradients:
- Concentration Gradient: A difference in the concentration of a chemical across the membrane.
- Electrochemical Gradient: The combined influence of a concentration gradient and an electrical gradient (charge difference) across the membrane.
Passive Transport: Moves substances down their concentration gradient; does not require energy (ATP).
- Simple Diffusion: Movement of molecules through the lipid bilayer (e.g., $O2, CO2$ ).
- Facilitated Diffusion: Movement of molecules through a protein channel or carrier.
- Osmosis: The net movement of water across a selectively permeable membrane.
Active Transport: Moves substances against the concentration gradient; requires energy (ATP).
Vesicular Transport:
- Endocytosis: Movement of substances into the cell via a vesicle.
- Pinocytosis: "Cell Drinking"; ingestion of extracellular fluid.
- Phagocytosis: "Cell Eating"; ingestion of large solid particles.
- Exocytosis: Movement of substances out of the cell via a vesicle.

13. Cell Division

Mitosis: The process of nuclear division that produces two genetically identical daughter cells for growth and repair.
- Interphase: The cell is metabolically active, performing its normal functions, and preparing for division by replicating its DNA and organelles. Not part of the actual division process (mitosis) but is an essential part of the complete Cell Cycle.
- Prophase: Chromosomes become visible and are scattered within the dissolving nucleus, captured by spindle fibers.
- Metaphase: Chromosomes are aligned single-file at the metaphase plate (the cell's equator); spindle fibers are fully attached.
- Anaphase: Chromosomes move to opposite poles of the cell.
- Telophase: Chromosomes are clustered at opposite poles, and a new nuclear envelope reforms around each cluster, forming two new nuclei.
- Cytokinesis: Not a part of nuclear division; it is the division of the cytoplasm. Chromosomes are passive and inside the two newly formed nuclei.
Meiosis: A special type of nuclear division occurring in reproductive organs that produces four genetically distinct gametes (sperm or egg cells) for sexual reproduction.