Human Physiology 261 Midterm Study Guide: Blood & Respiratory

Definitions

• Perfusion: The passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue.

• Ventilation: The process of moving air into and out of the lungs.

• Alveoli: Tiny air sacs in the lungs where gas exchange occurs between air and blood.

• Surfactant: A substance (phospholipid) that reduces surface tension in the alveoli, preventing them from collapsing.

• Boyle’s Law: The law states that the volume of a gas is inversely proportional to its pressure at a constant temperature. Mathematically P1V1 = P2V2.

• Alveolar Ventilation Rate: The volume of fresh air that reaches the alveoli per minute. Calculated as AVR = (Tidal Volume - Dead Space) \, \times \, Respiratory Rate.

• Erythropoietin: A hormone produced by the kidneys that stimulates red blood cell production in the bone marrow.

• Thrombopoietin: A hormone produced by the liver that stimulates platelet production in the bone marrow.

• Hematocrit: The percentage of blood volume that is made up of red blood cells.

• Hemolysis: The destruction of red blood cells, leading to the release of hemoglobin.

• Fibrinolysis: The enzymatic breakdown of fibrin in blood clots.

Lists

• Plasma Composition, Percentage of Each, and Their Functions:

  • Water (90%): Solvent for carrying other substances; absorbs heat.

  • Plasma proteins (8%): Include albumin (maintains osmotic pressure), globulins (antibodies, transport), and fibrinogen (blood clotting).

  • Electrolytes (1%): Ions like Na+, K+, Cl-, etc.; maintain osmotic pressure and pH buffering.

  • Nutrients (1%): Glucose, amino acids, lipids, vitamins; energy source and building blocks.

  • Respiratory gases (1%): Oxygen and carbon dioxide; involved in respiration.

  • Hormones (Less than 1%): Chemical messengers that regulate body functions.

• Function of Red Blood Cells:

  • Transport oxygen from the lungs to the body tissues and carbon dioxide from the body tissues to the lungs.

• Functions of Platelets:

  • Blood clotting by forming a platelet plug and releasing factors that initiate the coagulation cascade.

• Functions of the Respiratory System:

  • Gas exchange: Oxygen intake and carbon dioxide removal.

  • Regulation of blood pH.

  • Voice production.

  • Olfaction.

  • Protection against inhaled pathogens.

• The Two Types of Alveolar Cells and Their Functions:

  • Type I alveolar cells: Form the structure of the alveolar walls, allowing gas exchange.

  • Type II alveolar cells: Secrete surfactant, which reduces surface tension and prevents alveolar collapse.

• Respiratory Volumes and Capacities (spirometry video):

  • Tidal Volume (TV): Amount of air inhaled or exhaled with each normal breath (approximately 500 mL).

  • Inspiratory Reserve Volume (IRV): Amount of air that can be forcefully inhaled after a normal tidal volume inhalation.

  • Expiratory Reserve Volume (ERV): Amount of air that can be forcefully exhaled after a normal tidal volume exhalation.

  • Residual Volume (RV): Amount of air remaining in the lungs after a forced exhalation (cannot be measured by spirometry).

  • Inspiratory Capacity (IC): TV + IRV

  • Functional Residual Capacity (FRC): ERV + RV

  • Vital Capacity (VC): TV + IRV + ERV

  • Total Lung Capacity (TLC): TV + IRV + ERV + RV

Previously Covered Chapters

• Make sure to review the previous study guides.

Define Previously Covered Chapters

• Homeostasis: Maintaining a stable internal environment despite external changes.

• Energy: The capacity to do work.

• Activation Energy: The energy required to start a chemical reaction.

• Exergonic Reactions: Reactions that release energy.

• Enzymes: Biological catalysts that speed up chemical reactions by lowering activation energy.

• Enzyme Specificity: The ability of an enzyme to bind to one specific substrate.

• Exocytosis: The process by which cells release substances into the extracellular environment via vesicles.

• Resting Membrane Potential: The electrical potential difference across the plasma membrane of a cell when it is not stimulated.

• CNS: Central Nervous System; brain and spinal cord.

• Overshoot Point: The point during an action potential when the membrane potential becomes positive.

• The All-Or-None Principle of Action Potential: An action potential either fires completely or does not fire at all.

• Gluconeogenesis: The synthesis of glucose from non-carbohydrate precursors.

• Acromegaly: A hormonal disorder resulting from excessive growth hormone after the growth plates have closed, characterized by enlarged extremities and facial features.

• Cushing’s Disease: A hormonal disorder caused by prolonged exposure of the body's tissues to high levels of the hormone cortisol.

Lists Previously Covered Chapters

• Cellular Organelles and Their Functions:

  • Nucleus: Contains DNA and controls cell activities.

  • Ribosomes: Synthesize proteins.

  • Endoplasmic Reticulum (ER): Synthesizes and transports proteins and lipids.

  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

  • Lysosomes: Digest cellular waste and debris.

  • Mitochondria: Produce ATP through cellular respiration.

  • Centrioles: Organize microtubules during cell division.

• Steps of Protein Synthesis:

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

  • Translation: mRNA is translated into a protein at the ribosome.

• Intracellular and Extracellular Ions:

  • Intracellular: High concentration of K+, proteins, and phosphates.

  • Extracellular: High concentration of Na+, Cl-, and Ca2+.

• Function of Na+/K+ Pump:

  • Maintains resting membrane potential by pumping 3 Na+ ions out of the cell and 2 K+ ions into the cell.

• Rules of Diffusion:

  • Substances move from an area of high concentration to an area of low concentration.

  • Diffusion rate is affected by temperature, concentration gradient, and molecular size.

• Hormonal Classification:

  • Amino acid-based hormones: Water-soluble that binds to surface receptors on target cells.

  • Steroid hormones: Lipid-soluble hormones derived from cholesterol that bind to intracellular receptors.

• Hormones of the Anterior Pituitary Gland and Their Functions:

  • Growth Hormone (GH): Promotes growth and metabolism.

  • Prolactin (PRL): Stimulates milk production.

  • Adrenocorticotropic Hormone (ACTH): Stimulates adrenal cortex to release hormones.

  • Thyroid-Stimulating Hormone (TSH): Stimulates thyroid gland to release hormones.

  • Follicle-Stimulating Hormone (FSH): Stimulates follicle development in ovaries and sperm production in testes.

  • Luteinizing Hormone (LH): Triggers ovulation in females and testosterone production in males.

• List and Explain the Phases of Neuronal Action Potential:

  • Resting state: Voltage-gated Na+ and K+ channels are closed; resting membrane potential is maintained.

  • Depolarization: Na+ channels open, Na+ rushes into the cell, making the inside more positive.

  • Repolarization: Na+ channels close, K+ channels open, K+ rushes out of the cell, restoring the negative membrane potential.

  • Hyperpolarization: K+ channels remain open, causing an excessive efflux of K+, resulting in a more negative membrane potential than the resting state.

  • Return to resting state: K+ channels close, and the Na+/K+ pump restores the resting membrane potential.

• Cells of the Pancreas and Their Functions:

  • Alpha cells: Secrete glucagon, which increases blood glucose levels.

  • Beta cells: Secrete insulin, which decreases blood glucose levels.

  • Delta cells: Secrete somatostatin, which inhibits the release of insulin and glucagon.

Transcription:

-The first step in protein synthesis begins in the nucleus of the cell. During this process, the enzyme RNA polymerase binds to a specific region of the DNA strand, unwinding the DNA that contains the gene to be expressed. The RNA polymerase then synthesizes a single strand of messenger RNA (mRNA) by complementing the DNA template. This mRNA strand is a complementary copy of the gene, where thymine (T) in DNA is replaced by uracil (U) in RNA. Once the mRNA is synthesized, it undergoes processing that includes adding a 5' cap and a poly-A tail, and splicing out introns (non-coding sequences) to produce a mature mRNA molecule.

Translation: The mature mRNA then leaves the nucleus and enters the cytoplasm, where it binds to a ribosome, the site of protein synthesis. The ribosome reads the sequence of codons (three-nucleotide sequences) along the mRNA. Transfer RNA (tRNA) molecules, which carry specific amino acids, recognize the codons on the mRNA through their anticodon region. Each tRNA molecule has an amino acid attached to it that corresponds to the codon it recognizes.

As the ribosome moves along the mRNA, tRNA molecules bring their amino acids in the correct sequence, forming a polypeptide chain. The ribosome catalyzes the formation of peptide bonds between adjacent amino acids, resulting in the elongation of the growing polypeptide. This process continues until the ribosome reaches a stop codon (UAA, UAG, or UGA), which signals the termination of protein synthesis. The completed polypeptide chain then detaches from the ribosome and undergoes folding and post-translational modifications, such as phosphorylation or glycosylation, to become a functional protein.