BIOL 2340 Human A&P

Anatomy

Study of the structure of the body and the relationships among body parts.

• Example: Examining the structure of the heart.

Physiology

Study of the function of body parts and how they work together.

• Example: Understanding how the heart pumps blood.

Cytology

• Study of cells and their internal structures.

Histology

• Study of tissues, which are groups of cells working together for a specific function.

Levels of organization in the human body (from simplest to most complex):

• Chemical level: Atoms & molecules

• Cellular level: Cells, the basic functional units

• Tissue level: Groups of similar cells performing a function

• Organ level: Structures made of different tissues performing specific functions

• Organ system level: Organs working together for a common purpose

• Organismal level: The whole body functioning as one unit

Necessary Life Functions

• Maintaining boundaries (e.g., cell membrane, skin)

• Movement (muscles, transport of substances)

• Responsiveness (ability to sense and respond to stimuli)

• Digestion (breaking down food and absorbing nutrients)

• Metabolism (all chemical reactions in the body)

• Excretion (removal of wastes)

• Reproduction (cellular and organismal)

• Growth (increase in size and number of cells)

Integumentary System

Protects body, regulates temperature, sensory info

Skin, hair, nails, glands

Skeletal System

Supports/protects, blood cell production, mineral storage

Bones, cartilage, ligaments

Muscular System

Movement, posture, heat production

Skeletal muscles, tendons

Nervous

Rapid communication, response to stimuli

Brain, spinal cord, nerves

Endocrine

Hormone production, long-term regulation

Glands (thyroid, pituitary, adrenal)

Cardiovascular

Transport of nutrients, gases, wastes

Heart, blood, blood vessels

Lymphatic/Immune

Defends against infection, returns fluids

Lymph nodes, spleen, thymus, lymph vessels

Respiratory

Gas exchange

Lungs, trachea, bronchi, nasal cavity

Digestive

Food breakdown, nutrient absorption, waste elimination

Stomach, intestines, liver, pancreas

Urinary

Waste removal, water & electrolyte balance

Kidneys, bladder, ureters

Reproductive

Produces sex cells & hormones

Ovaries, testes, uterus, prostate

Homeostasis

Maintaining a stable internal environment despite external changes.

Autoregulation vs. Extrinsic Regulation

• Autoregulation (intrinsic): Local response within a tissue/organ.

  • Example: Blood vessels dilating in a tissue due to low oxygen.

• Extrinsic regulation: Controlled by nervous/endocrine system, affecting the whole body.

  • Example: Sweating to lower body temperature.

Components of Homeostatic Control

• Receptor: Detects change (stimulus)

• Control center: Determines response (usually brain/spinal cord)

• Effector: Executes response to adjust the condition

c) Negative Feedback

• Purpose: Opposes initial change to restore balance

• Examples:

  • Regulation of body temperature

  • Blood glucose levels

Positive Feedback:

• Purpose: Amplifies the original stimulus

• Examples:

  • Blood clotting

  • Childbirth (uterine contractions)

  • Action potential (depolarization)

  • Suckling reflex in breastfeeding

Atomic number

Number of protons in an atom.

Mass number

Total number of protons + neutrons.

Isotopes

Atoms of the same element with different numbers of neutrons.

Atomic weight

Average mass of all isotopes of an element.

Abundant atoms in the human body

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N), Calcium (Ca), Phosphorus (P).

Electron energy levels

Electrons occupy shells around the nucleus; lower shells fill first.

Molecule compound

• Substance made of two or more different elements chemically combined.

Ionic bonds:

Formed when electrons are transferred from one atom to another, creating ions (cation +, anion −).

Covalent bonds

Formed when atoms share electrons.

Nonpolar covalen

Electrons shared equally.

Polar covalent

Electrons shared unequally, creating partial charges.

Hydrogen bonds

Weak attractions between partial positive hydrogen and electronegative atoms (like O or N).

Reactants

• Starting substances.

Products

Substances formed.

Kinetic energy

Energy of motion.

Potential energy

Stored energy.

Decomposition (catabolism):

• Breaking down molecules.

Synthesis (anabolism)

Building larger molecules.

Enzyme catalysis

• Speeds up reactions by lowering activation energy.

• Reaction energy diagrams: Show energy changes.

• Endergonic: Energy absorbed.

• Exergonic: Energy released.

Organic molecule

Contain carbon and hydrogen (carbs, lipids, proteins, nucleic acids).

Inorganic molecule

• Usually lack carbon (water, salts, acids, bases).

Water properties

High heat capacity, cohesion, solvent, chemical reactivity, cushioning.

Aqueous solutions

• Water-based solutions.

Hydrophobic

Repelled by water.

Dissociation in water

• Forms H⁺ and OH⁻ ions.

Acidic

pH < 7 (high H⁺ concentration)

Neutral

pH = 7

Basic/Alkaline

pH > 7 (low H⁺ concentration)

Buffers

• Resist pH changes.

Monosaccharides

Simple sugars (glucose, fructose).

Disaccharides

Two monosaccharides (sucrose, lactose).

Polysaccharides

Many monosaccharides (glycogen, starch).

Ring vs. linear molecules

Sugars can exist in ring or chain form.

Carb Atomic composition:

C, H, O (usually 1:2:1).

Carb Functions

• Energy source, energy storage, structural components.

Fats (triglycerides):

• Composed of glycerol + fatty acids.

• Functions: Energy storage, insulation, protection.

• Saturated Fats

• Saturated: No double bonds, solid at room temp.

• Unsaturated Fats

• Unsaturated: Double bonds, liquid at room temp.

Steroids

• Composed of 4 carbon rings.

• Functions: Hormones (estrogen, testosterone), cell membrane component (cholesterol).

Phospholipids

• Structure: Glycerol + 2 fatty acids + phosphate group.

• Properties: Amphipathic (hydrophilic head, hydrophobic tail).

• Functions: Form cell membranes, micelles in aqueous solutions.

DNA

Double-stranded, stores genetic info.

RNA

Single-stranded, involved in protein synthesis.

Hydrogen bonding

Holds DNA strands together (A-T, G-C).

Energy molecules

ATP, NAD, FAD, cAMP/AMP – store and transfer energy.

DNA replication

• Leading strand: Continuous synthesis.

• Lagging strand: Discontinuous, forms Okazaki fragments.

Amino acids

Building blocks of proteins.

Central dogma:

DNA → mRNA → protein.

Transcription

DNA → RNA

Enzyme

RNA polymerase

Gene

DNA segment coding for protein

Steps

Initiation → Elongation → Termination

mRNA maturation

Splicing, capping, poly-A tail, export to cytoplasm

Translation

mRNA → protein

Ribosome structure

Large + small subunit

tRNA

Carries amino acids to ribosome, anticodon matches mRNA codon

Translation steps

Initiation → Elongation → Termination

Peptide bond formation

Joins amino acids into polypeptides

Protein folding:

• Primary: Amino acid sequence

• Secondary: α-helix, β-sheet

• Tertiary: 3D folding

• Quaternary: Multiple polypeptides together

Cell biology

• Study of cell function, interactions, and life processes.

Somatic cells:

All body cells except sex cells; diploid (2n).

Sex cells (gametes):

Sperm & egg; haploid (n), combine during fertilization.

Plasma Membrane

• Functions

• Physical barrier, regulates entry/exit of substances

• Cell communication and signaling

• Structural support

Phospholipid bilayer:

• Hydrophilic heads outside, hydrophobic tails inside

Membrane proteins Integral

Embedded, transport channels, receptors

Membrane proteins Peripheral

• On surface, structural support, signaling

Membrane carbohydrates:

• Glycoproteins/glycolipids for cell recognition and adhesion

Cytoskeletonv

• Microfilaments, intermediate filaments, microtubules; supports shape, movement.

Microvilli

Increase surface area for absorption.

Cilia

Move substances along cell surface.

Ribosomes

Protein synthesis; free (cytosol) or bound (RER).

Rough (Endoplasmic Reticulum) ER

Ribosome-studded, protein synthesis

Smooth ER

• Lipid synthesis, detoxification, calcium storage

Golgi apparatus

Modifies, sorts, packages proteins; protein traffic system

Lysosomes

Digest cellular waste, foreign substances

Peroxisomes

Detoxify harmful substances, metabolize fatty acids

Mitochondria

• ATP production via oxidative phosphorylation

Nucleus

• Stores DNA, site of transcription

• Chromatin: DNA + proteins; condenses into chromosomes during mitosis

Entropy

Measure of disorder; drives diffusion.