Body Organization & Homeostasis

Body Organization & Homeostasis

• Metabolism is the total of chemical and physical reactions in the body.
• Anabolism and catabolism are the two forms of metabolic activity.
• The levels of organization in the body from smallest to largest are: chemical, organelle, cellular, tissue, organ, organ system, and organism.
• The four types of body tissues include: epithelial, nervous, muscle, and connective.
• Bilateral symmetry: both left and right sides.
• Ipsilateral: on the same side.
• Contralateral: on opposite sides.
• Supine: laying down face up.
• Prone: laying down face down.
• Lateral is indicated by "A"
• Medial is indicated by "B"
• Proximal is indicated by "C"
• Distal is indicated by "D"
• Posterior is indicated by "E"
• Anterior is indicated by "F"
• Superior is indicated by "G"
• Inferior is indicated by "H"
• Lumen: hollow cavity in an organ.
• Medullary: inner core of an organ.
• Cortical: outer region of an organ.
• Sagittal plane divides the body into left and right portions.
• Coronal plane divides the body into front and back portions.
• Transverse plane divides the body into top and bottom portions.
• Dorsal cavities include the spinal cavity (containing spinal cord) and cranial cavity (containing the brain).
• Ventral cavities include the thoracic cavity (containing heart/lungs) and abdominopelvic cavity (containing intestines, stomach, bladder, and reproductive organs).
• The abdominopelvic regions include:
  • Right hypochondriac, epigastric, and left hypochondriac regions.
  • Right lumbar, umbilical, and left lumbar regions.
  • Right iliac, hypogastric, and left iliac regions.
• Homeostasis involves maintaining a stable internal environment against changing conditions.
• The body uses regulatory mechanisms to maintain stability.
• Set point: the optimal point for peak body conditions.
• Homeostatic variables: body functions such as heart rate, body temperature, and blood pressure.
• Feedback loops in the body detect changes in body variables that are abnormal and generate a response.
• The flow of information in a response pathway: Stimulus -> Receptor -> afferent pathway -> integration center -> response signal -> effector via efferent pathway.
• Positive feedback loops move away from homeostasis. An example is releasing hormones during childbirth.
• Negative feedback loops move back toward homeostasis. An example is shivering when cold.
• Protons and neutrons are subatomic particles found in the nucleus.
• Electrons are subatomic particles found orbiting in shells.
• Atomic number: number of protons.
• Mass number: number of protons and neutrons together.
• Chemical bonds form through the interaction of outer shell electrons of two atoms.
• Multiple atoms bonding together result in molecules.
• The three types of chemical bonds from strongest to weakest:
  • Ionic: strongest, involves cations (+ charge) and anions (-), and the exchange of electrons.
  • Covalent: medium strength, can be polar covalent (semi-charged, unequally shared) or nonpolar (equally shared, neutral).
  • Hydrogen: weakest, involves interaction between hydrogen (partial + charge) and other atoms with partial charge (e.g., water).
• Hydrolysis: breaking larger molecules down to smaller molecules using water, associates with catabolism
• Condensation reaction: building larger molecules from smaller ones, releasing water, associates with anabolism
• Organic compounds contain both carbon and hydrogen.
• Inorganic compounds do not contain both carbon and hydrogen.
• Water (H2O) is the most important and abundant compound in the body.
• Proteins are the most abundant organic compound in the body.
• Solvent: something that used to dissolve things in.
• Solutes: materials that are dissolved.
• The four major macromolecules in the body:
  • Carbohydrates: hydrated carbons.
  • Lipids: nonpolar compounds that are hydrophobic.
  • Proteins: most abundant organic compound.
  • Nucleic acids: polymers of nucleotides.
• The three forms of carbohydrates: monosaccharides, disaccharides, polysaccharides.
• Proteins categorized as structural and functional
• Amino acids are joined together via peptide bonds
• Primary protein structure: a simple sequence of amino acids.
• Secondary protein structure: amino acid chains that form patterns.
• Tertiary protein structure: the final 3D shape of a protein.
• Quaternary protein structure: 3D protein shapes arranged in a large complex.
• The 3 components of a nucleotide are: pentose, phosphate group, and a nitrogenous base.
• ATP is the body's energy currency because it has high-energy chemical bonds that are easy to break.

Cells

• The plasma membrane is a semi-permeable barrier that surrounds the cell, protects it, and allows specific substances to enter.
• Phospholipids form the plasma membrane due to their hydrophilic heads and hydrophobic tails.
• Heads face out, and tails face in.
• Lipid-soluble molecules can easily pass through the plasma membrane, while water-soluble molecules cannot.
• Water cannot easily pass through but can via osmosis.
• Cholesterol molecules provide fluidity and flexibility to the plasma membrane.
• Integral membrane proteins (IMPs) have four main functions: signaling, identifying foreign objects, transport, and connecting with other cells' plasma membranes.
• The two types of transport proteins in the plasma membrane are carrier and channel proteins.
• Aquaporins are channel proteins that transport water.
• Rough ER, studded with ribosomes, produces proteins.
• Smooth ER produces lipids and carbohydrates and detoxifies.
• The Golgi apparatus packages and processes proteins from the ER and sends them where needed in vesicles.
• Lysosomes use enzymes to break down unneeded proteins.
• Proteasomes destroy abnormal, misfolded proteins.
• Peroxisomes break down fatty acids and detoxify.
• Peroxidase and catalase are the two enzymes that contribute to the functioning of peroxisomes.
• The mitochondria is important because it is the location of cellular respiration.
• The inner membrane folds of the mitochondria are called cristae.
• DNA is packaged into chromosomes in the nucleus.
• Each human cell contains 46 chromosomes.
• The cytoskeleton is the structural support system of the cell.
• Microfilaments, microtubules, and centrosomes that arrange the microtubules make up cytoskeleton.
• Cilia aids in movement of mucus
• Microvilli absorbs nutrients
• Flagella is a tail-like structure that helps sperm cells swim; found in sperm, ear, and respiratory cells.
• Desmosomes are protein complexes that attach cell membranes.
• Gap junctions are protein channels that connect cytoplasm.
• Tight junctions are tight bands that form water-tight seals; "ties" cells
• Diffusion: movement of molecules over a membrane from area of high concentration to low concentration.
• Concentration gradient: the difference in concentration in one area versus another.
• The steeper the concentration gradient, the faster the molecules move.
• Osmosis: movement of water from an area of high water concentration to an area of low water concentration.
• Osmotic pressure: the force that keeps water from moving.
• Water moves toward an area of high solute concentration.
• Isotonic solution: equal percentage of solute concentration in ECF and ICF, no cell change.
• Hypotonic solution: lower percentage of solute concentration in ECF than ICF, water swells the cell and it bursts.
• Hypertonic solution: higher percentage of solute concentration in ECF than ICF, water leaves the cell, and it shrivels.
• Facilitated diffusion: transport via carrier and channel proteins, needed for polar, large, or charged molecules.
• Membrane pumps transport against the concentration gradient.
• They move substances from an area of low concentration to high concentration.
• Requires ATP to move things in/out of cell against the gradient.
• The two types of vesicular transport are exocytosis and endocytosis.
• Endocytosis includes phagocytosis and pinocytosis.
• Enzymes are a subclass of functional proteins that activate metabolic reactions.
• They are responsible for helping to overcome activation energy.
• The active site of an enzyme acts as the portion where enzyme fits its substrate.
• Cellular respiration is a catabolic process where cells break down glucose into CO2 and water and release energy.
• Chemical equation: C6H12O6 + 6O2 ----> 6CO2+6H20 + energy.
• Glycolysis occurs in the cell cytoplasm and breaks glucose down into 2 pyruvate molecules.
• It is anaerobic.
• If oxygen is present, the molecules move to the 2 other pathways; if not, it’s converted to lactic acid.
• The citric acid cycle occurs in the mitochondrial intermembrane space.
• It starts with pyruvate molecules and converts to Acetyl-CoA; it is aerobic.
• Most energy in this pathway is produced as electrons.
• The electron transport chain (ETC) occurs in the inner mitochondrial membrane.
• Electrons are transported through the membrane via electron carriers and then accepted by oxygen, which is aerobic.
• The energy generated from shuffling is then used to phosphorylate ADP into 30-32 ATP.
• Protein synthesis: anabolic, translation and transcription.
• DNA is transcribed to RNA, which is then translated to form proteins.
• DNA is double helix, contains deoxyribose, thymine.
• RNA is a single strand and contains ribose, uracil.
• The four phases of the cell cycle:
  • G1: proteins produced according to genetic code form larger organelles and plasma membrane
  • S (synthesis): DNA reproduction occurs and produces 2 copies of the genome to be passed to daughter cells.
  • G2: cell grows via protein synthesis, formation of high order structures.
  • M (mitosis): cell division occurs, resulting in 2 identical daughter cells.
• The four phases of mitosis:
  • Prophase- formation of chromosomes from DNA and formation of mitotic spindle from centrioles
  • Metaphase- chromosomes line up at middle of cell
  • Anaphase- Chromosomes ripped apart by mitotic spindle fibers, go to opposite sides of cells and form 2 pools of identical genetic information
  • Telophase- Two identical daughter cells formed from the genetic info, mitotic spindle disappears
• Mitosis happens in Somatic cells.
• Meiosis matures sex cells (gametes)
• It has two stages: Meiosis I and Meiosis II.
• Results in 4 non-identical daughter cells with 23 chromosomes.