Anatomy and Physiology 12 Final Exam Study Guide

Anatomy and Physiology 12 Final Exam Overview

• Final Exam Format: The final exam consists of 50 questions in total. This includes 8 True/False questions and 42 Multiple Choice questions.

• Required Diagrams and Graphs: Students are expected to be able to identify, label, and explain several key biological diagrams, including cell structures, heart anatomy, action potential graphs, reproductive systems, nephron structure, and molecular structures.

Membrane Potential and the Action Potential Graph

• Graph Overview: The graph represents the change in membrane potential over time as a nerve impulse (action potential) passes through a neuron. The $y$-axis measures potential in millivolts ($mV$), ranging from approximately $-80\,mV$ to $+40\,mV$. The $x$-axis represents time in milliseconds ($ms$).

• Phase A: Resting Potential: The membrane is at rest, typically at $-70\,mV$. The sodium-potassium pump is active, and the membrane is polarized.

• Phase B: Threshold and Depolarization: A stimulus reaching the threshold (around $-55\,mV$) triggers the opening of voltage-gated sodium ($Na^+$) channels. $Na^+$ ions rush into the cell, making the inside less negative.

• Phase C: Action Potential Peak: The membrane potential reaches its maximum positive value, often around $+40\,mV$. At this point, $Na^+$ channels close and $K^+$ channels open.

• Phase D: Repolarization: High concentrations of potassium ($K^+$) ions exit the cell through open voltage-gated channels, causing the membrane potential to drop back toward a negative value.

• Phase E/F: Hyperpolarization (Undershoot): The potential drops slightly below the resting level because $K^+$ channels stay open slightly too long. This is part of the refractory period when the neuron cannot fire another impulse immediately.

• Phase G: Return to Resting Potential: The sodium-potassium pump restores the original ionic concentrations, returning the membrane to $-70\,mV$.

• The Threshold Concept: The threshold is the minimum level of depolarization required to trigger an action potential. A stimulus only produces an impulse if it is strong enough to reach this threshold; otherwise, no impulse is generated (the "all-or-none" principle).

Biochemistry and Molecular Interactions

• Water and Hydrogen Bonding: In a diagram of water molecules, the bond labeled $x$ between the Hydrogen of one water molecule and the Oxygen of another is a Hydrogen Bond.

  • Cooling Mechanics: Water effectively cools the body because of its high heat of vaporization. To evaporate, heat energy from the body must be used to break these hydrogen bonds ($x$). As water turns to gas and leaves the skin, it carries that heat away.

• Chemical Bond Strengths:

  • Covalent Bonds: Generally the strongest, involving shared electrons between atoms.

  • Ionic Bonds: Strong, involving the electrostatic attraction between oppositely charged ions.

  • Hydrogen Bonds: Relatively weak individually but strong in large numbers; they are intermolecular forces rather than true atomic bonds.

• Acids and Bases: A substance that releases hydroxide ions ($OH^-$) is a base (or alkaline substance). Releasing $OH^-$ ions causes the $pH$ of a solution to increase (moving closer to 14).

• Biological Molecules:

  1. Proteins: Monomers are amino acids. Involved in structure, enzymes, and transport.

  2. Carbohydrates: Monomers are monosaccharides (e.g., glucose). Used for short-term energy.

  3. Lipids: Components include glycerol and fatty acids. Used for long-term energy and membranes.

     • Saturated Fatty Acids: Have no double bonds between carbons; carbons are "saturated" with hydrogens. Usually solid at room temperature.

     • Unsaturated Fatty Acids: Contain one or more double bonds, causing kinks in the chain. Usually liquid at room temperature.

  4. Nucleic Acids: Monomers are nucleotides. Includes DNA and RNA for genetic information.

DNA Structure and Gene Expression

• DNA vs. RNA Differences:

  • Sugar: DNA contains deoxyribose; RNA contains ribose.

  • Bases: DNA uses Thymine ($T$); RNA uses Uracil ($U$) instead of Thymine.

  • Strands: DNA is double-stranded (double helix); RNA is typically single-stranded.

• DNA Structure Concepts:

  • Anti-parallel Strands: The two strands of the DNA double helix run in opposite directions (one $5'$ to $3'$, the other $3'$ to $5'$).

  • Complementary Base Pairing: Adenine ($A$) always pairs with Thymine ($T$), and Cytosine ($C$) always pairs with Guanine ($G$).

• DNA Replication: The purpose of replication is to create an exact copy of the DNA so that when a cell divides, each new daughter cell receives a complete set of genetic instructions.

• Protein Production (Translation): Proteins are produced at the ribosomes, which are often located on the Rough Endoplasmic Reticulum (RER) or floating freely in the cytoplasm. mRNA carries the code from the nucleus to the ribosome.

• Codon Chart and Mutations:

  • Mutation Example: A DNA mutation that changes a codon from $UGU$ (Cysteine) to $UGG$ (Tryptophan).

  • tRNA Binding: A specific Transfer RNA (tRNA) carries a specific amino acid. The tRNA has an anticodon that is complementary to the mRNA codon. If the codon changes due to a mutation, a tRNA carrying a different amino acid will bind to the ribosome, altering the resulting protein.

The Digestive System

• Organs and Functions:

  • Mouth: Mechanical digestion and initial chemical digestion (starch).

  • Esophagus: Transports food to the stomach via peristalsis.

  • Stomach: Chemical digestion of proteins and mechanical churning.

  • Small Intestine: Major site of chemical digestion and nutrient absorption.

  • Large Intestine: Reabsorption of water and formation of feces.

• Food Movement: Food moves through the tract via peristalsis, a rhythmic contraction of smooth muscle. The path is: Mouth $\rightarrow$ Pharynx $\rightarrow$ Esophagus $\rightarrow$ Stomach $\rightarrow$ Small Intestine $\rightarrow$ Large Intestine $\rightarrow$ Rectum $\rightarrow$ Anus.

• Nomenclature of Food:

  • Bolus: Food mixed with saliva in the mouth and esophagus.

  • Chyme: The semi-liquid mass of partially digested food in the stomach and small intestine.

  • Feces: Waste material in the large intestine and rectum.

• Digestive Sphincters:

  • Cardiac (Lower Esophageal) Sphincter: Prevents stomach acid from backing up into the esophagus.

  • Pyloric Sphincter: Controls the passage of chyme from the stomach into the small intestine.

  • Anal Sphincter: Controls the exit of feces from the body.

• Enzymes: Key enzymes include Salivary Amylase (carbs), Pepsin (proteins in stomach), Trypsin (proteins in small intestine), and Lipase (fats).

The Respiratory System

• Mechanics of Breathing:

  • Inhalation: The diaphragm contracts and moves downward; the rib cage moves up and out. This increases thoracic volume, lowers internal pressure, and pulls air in.

  • Exhalation: The diaphragm relaxes and moves upward; the rib cage moves down and in. This decreases volume, increases pressure, and pushes air out.

• Diffusion at the Alveoli: Oxygen moves from the air in the alveoli (high concentration) into the blood in the capillaries (low concentration). Carbon dioxide moves from the capillaries (high concentration) into the alveoli (low concentration) to be exhaled.

• Types of Respiration:

  1. External Respiration: Gas exchange between the air in the alveoli and the blood in pulmonary capillaries.

  2. Internal Respiration: Gas exchange between the blood in systemic capillaries and the tissue cells.

  3. Cellular Respiration: The metabolic process inside the mitochondria where oxygen is used to produce ATP, releasing $CO_2$ as a byproduct.

The Reproductive System

• Male Reproductive System Glands:

  • Seminal Vesicles: Contribute fructose (energy for sperm) and prostaglandins to semen.

  • Prostate Gland: Adds an alkaline fluid to neutralize the acidity of the female reproductive tract.

  • Bulbourethral (Cowper's) Glands: Release a lubricating mucus prior to ejaculation.

• Semen Composition: Semen is made of sperm cells plus secretions from the seminal vesicles, prostate, and bulbourethral glands.

• Fertilization: The egg is typically fertilized by the sperm in the Oviduct (also known as the Fallopian tube).

• Hormones:

  • Male: Testes release Testosterone.

  • Female: Ovaries release Estrogen and Progesterone.

Cellular Movement and Organization

• Gas Transport: Gases like $CO_2$ and $O_2$ move in and out of cells via simple diffusion through the phospholipid bilayer, moving from areas of high concentration to low concentration.

• Levels of Organization: The human body is organized from simplest to most complex: Chemical Level $\rightarrow$ Cellular Level $\rightarrow$ Tissue Level $\rightarrow$ Organ Level $\rightarrow$ Organ System Level $\rightarrow$ Organism Level.