Major Themes of A&P Lecture 1 PDF

Major Themes of A&P Chapter 1 Homeostasis, negative and positive feedback mechanisms Objectives Define and describe differences between anatomy and physiology. Explain how evolution operates on populations and species Describe adaptations humans have evolved. Explain...

Major Themes of A&P Chapter 1 Homeostasis, negative and positive feedback mechanisms Objectives Define and describe differences between anatomy and physiology. Explain how evolution operates on populations and species Describe adaptations humans have evolved. Explain the concept of variation and why it is important in A&P. Define homeostasis and discuss different feedback mechanisms. Anatomy and Physiology  Comparative Anatomy and Physiology Why is this important for humans? What information can we get from comparative studies? Human Implications Closest relative? Chimpanzee Genetic differences (%)? 1.6% Why do we study evolution? Help choose animals for research Anatomy and physiology Medicinal derivatives E.g., viper venom is anticoagulant Human Shared Adaptations E.g., Opposable thumbs Stereoscopic vision Human Shared Adaptations Bipedalism What types of modifications needed? Human Adaptations Endurance Evaporative cooling Breathing (and not panting) while running Human Adaptations Brain size and folding Mouse Species evolution is likely more about changes in gene expression than in the actual products the genes code Missing regulatory DNA sequence in humans: One that appears to suppress the proliferation of neurons One that direct the formation of penile spines Present in other primates, including chimpanzees, gorillas, and orangutans Hierarchy of Complexity Organism Organ systems Organs Tissues Cells Organelles Molecules Atoms Figure 1.4 Anatomical Variation No two humans are exactly alike Diagrams show common organization 22 yrs., 128 lbs. (F) 154 lbs. (M), light physical activity, moderate caloric intake Examples Muscles Number of vertebrae Number of organs Left/right reversal of organization (situs inversus) Figure 1.5 People Vary Anatomical variation Physiological variation E.g., heart rate, blood pressure, metabolic rate. Why do we expect variation? Genetics Environment What does this mean for medical field? Dosage Not all procedures and histology slides will be identical Homeostasis Maintaining stability in a dynamic environment Hippocrates noticed body’s ability to self-restore Even without doctors. Built-in mechanisms to detect change Activate mechanism to oppose change Not always able to compensate in extreme cases Homeostasis Internal conditions are not always one specific value (e.g. temp, pH) Rather, a range of values around a set point (e.g. 7.35 – 7.45 blood pH) Dynamic equilibrium Hyperglyce mia Homeostasis Example: Body Heat Similar to thermostat control in houses Nerve cells in brain monitor blood temp. If too hot  vasodilation (widening of blood vessels) Still too hot  sweating mechanism If too cold  vasoconstriction Still too cold  shivering  Homeostasis Negative feedback mechanisms Help keep variables close to set point Body senses changes  Feedback Inhibition Body reverses effects of changes via effector Effect of the effector  shuts down the effector  prevents extreme in the Feedback Mechanism (loop) Receptor Integratio n center Effector Effecto r Integration Recepto Center r Positive Feedback Mechanism that amplifies change in the same direction Rapid change Can be harmful E.g. fevers (temp. too far away from set point)  Integrati Positive on Center Feedback in Childbirth Effector Rapidly amplifies change in the same direction Recept or Gradients and Flow Gravitational Movement occurs down Potential Energy gradients Higher GPE (difference/distance) Universal tendency Central concept of living systems Differences in Chemical concentration Electric charge Lower GPE Pressure Temperature Simple Diffusion No Gradient  0 net Concentration Concentration No Gradient  0 net flow Gradient Gradient flow Anatomical Positions Midline Anterior Posterio Medial r Superior Lateral Superfici Inferior al Deep Proximal Distal Anatomical Positions Terms can also be combined E.g., posterosuperior  back of the structure/body, around the top Terms used in naming  Anatomical Positions Planes (Frontal) Additional Material Read “Plural, Adjectival, and Possessive Forms” and Table 1.1 Next Lecture The Chemistry of Life (Chapter 2)