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Your body and how it works BIOL 201 Dr. Eric McElroy RHSC 235 Tel: 953-3707 e-mail: [email protected] Where to find Lecture Slides http://mcelroye.people.cofc.edu Textbooks: Save money, buy used online! Silverthorne (4th or 5th editions) Bruyere http://iclicker.com/registration/ Student ID = xxx-xx-xxx Registration ID st 1 QUIZ is NEXT WED! BASIC ASSUMPTIONS 1. The Universe is lawful 2. Biological systems are lawful Physiological processes are mechanistic and governed by chemistry and physics 3. There is NO VITAL FORCE no MAGIC! What is Physiology? 1) functions of anatomical structures 2) the mechanisms driving function. Structure: Muscle and bones Function: Support & Movement Physiological Mechanism: Sliding Filament Model Levels of Organization Membranes & Ions Neurons & Nerves Spinal Cord & Brain Organism: Integration of Systems HOMEOSTASIS Maintaining constant Internal Environment External Environment = changing Internal Environment Internal Environment: Fluid Compartments Capillary wall Cell membrane Blood cells Blood vessel Plasma 60% of blood Interstitial fluid (ISF) ECF Intracellular fluid (ICF) ICF Cell membrane Cells are Dynamic! Homeostasis = relative constancy of the ISF and BLOOD PLASMA EXTERNAL ENVIRONMENT Exchange Cells Blood Plasma Interstitial fluid (ISF) Intracellular fluid (ICF) EXTERNAL ENVIRONMENT Digestive Respiratory Urinary Integument Exchange Cells Blood Plasma Interstitial fluid (ISF) Vascular Intracellular fluid (ICF) Muscles Skeletal Nervous Heart Reproductive Endocrine 3 Basic Parts to All Homeostatic Mechanisms 1) Receptor – Senses Deviation from NORMAL levels 2) Integrator – Interprets deviation and signals for a response 3) Effector – Returns body to NORMAL level Homeostatic Mechanism are REFLEX ARCS! Reflex Arcs Knee Jerk Reflex Extreme Reflex Reflex Arcs are EVERYWHERE 2 Main Types of Homeostatic Mechanisms 1) Negative Feedback Loop Deviation from NORMAL results in a return to normal via feedback loop 2) Positive Feedback Loop Deviation from NORMAL results in a FURTHER deviation from normal RECEPTOR INTEGRATOR EFFECTOR Baroreceptor (Carotid Sinus) Brain (Cardiovascular Center) Heart 93 mm Hg MAP Time (min.) CLASSIC Negative feedback loop Example: Positive Feedback Loop Parturition = Childbirth Body compartments expressed as the % body weight of a 21 year old,70 kg (154 lbs) male 40% Solids 60% Body Fluids Intracellular Interstitial Plasma (40% TBW) (40% TBW) (16% TBW) (4% TBW) 28 kg 28 kg 11 kg 3 kg Bone Potassium, K+ Sodium, Na+ Na+ Protein Chloride, ClClAdipose Tissue HCO3HCO3Glucose Glucose Amino acids Amino acids. Fatty acids Fatty acids. No plasma Plasma proteins proteins Extracellular Fluid (20%)