VPHY 3100: Week of 11/2
VPHY 3100: Week of 11/2 VPHY 3100
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This 4 page Class Notes was uploaded by Lorin Crear on Saturday November 7, 2015. The Class Notes belongs to VPHY 3100 at University of Georgia taught by Dr. Li, Dr. Wells, Dr. Brown in Summer 2015. Since its upload, it has received 73 views. For similar materials see Elements of Physiology in Animal Science and Zoology at University of Georgia.
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Date Created: 11/07/15
Chapter 16: Respiration Chemoreceptor Control of Breathing o Decreased ventilation = increased arterial PCO2= increased plasma CO2 concentration o Brain Pathway Decreased pH of interstitial fluid Central chemoreceptors in medulla oblongata sense pH change Signal sent from chemoreceptors to respiratory centers of medulla oblongata o Blood Pathway Decreased pH of blood Peripheral chemoreceptors in aortic and carotid bodies sense pH change Signal sent from chemoreceptors to respiratory centers of medulla oblongata via sensory neurons o Convergence of Pathways Respiratory center signals motor neurons of spinal cord Motor neurons signal respiratory muscles Respiratory muscles increased depth and rate of ventilation (respiratory minute volume) Other modifiers of ventilation o Higher centers of the brain o Hering-Breuer reflex Stretch receptors in lungs o Proprioceptors In muscles and joints o Skin sensory receptors o Drugs Oxygen Transport o Oxidative Phosphorylation Main process of tissue metabolism Requires O +rom blood CO a2d H produced as waste (removed by blood) o Hemoglobin 90% of oxygen bound to hemoglobin during blood transportation Each hemoglobin can carry 4 oxygen molecules Forms “oxyhemoglobin” complex Made of 4 polypeptide chains Each with iron-containing, oxygen-binding, “heme” group 280 million hemoglobin molecules per red blood cell Each RBC can carry over a billion oxygen molecules % oxyhemoglobin saturation Proportion of oxyhemoglobin to total hemoglobin Assesses how well lungs oxygenate blood Measured with pulse oximeter or blood-gas machine Normal = 97% in systemic arteries and pulmonary veins Normal = 75% in systemic veins and pulmonary arteries Bohr effect Increased CO , decreased pH, and increased temperature reduce 2 affinity of hemoglobin for O2 o Active tissues (with build-up of CO )2receive more O 2 o Pushes oxyhemoglobin dissociation curve down and to the right Effect of 2,3-DPG RBCs produce 2,3-diphosphoglyceric acid (2,3-DPG) in response to hypoxia in tissues o Production increases if a person has increased oxygen demands o 2,3-DPG reduces affinity of hemoglobin for oxygen at tissue Increases delivery Carbon Dioxide Transport o 10% dissolved in plasma o 20% bound to hemoglobin (forms “carbaminohemoglobin” complex) o 70% transported as bicarbonate (HCO ) 3- Excess Capacity o Normal O and2CO excha2ge is accomplished in first 1/3 of pulmonary capillary o Remaining 2/3 = excess capacity for further exchange if needed o Excess capacity not present in metabolically active tissues, so it may take a while after exercise to restore normal concentrations Chapter 17: Urinary System Organs involved in urinary system o Adrenal glands o Kidneys o Renal arteries (branch of abdominal aorta) o Renal veins (branch of inferior vena cava) o Ureter o Urinary bladder o Urethra Maintaining Homeostasis o Control of extracellular fluid (ECF) volume and composition ECF volume Water ECF composition + + - Electrolytes (Na , K , Cl ) Minerals (PO 4 Mg , Ca ) 2+ - + Acid-base balance (HCO , 3 ) Toxic products of metabolism Kidneys o Structure Cortex (outer layer) Medulla (inner layer) Divided into sections called “pyramids” Pelvis Urine collects here before traveling down ureter Ureter Nephron Basic structural and functional unit of kidney Includes: o Afferent arteriole o Glomerular capsule (aka Bowman’s capsule) o Efferent arteriole o Peritubular capillary bed o Intermediate tubule (aka Loop of Henle) o Vasa recta capillaries Peritubular capillaries surrounding Loop of Henle Path of filtrate: o Afferent arteriole bowman’s capsule Bowman’s space proximal tubule Loop of Henle distal tubule collecting duct (several nephrons drain in one) renal pelvis Three Renal Processes to Production of Urine o Filtration Movement of water, small particles into through Glomerular capillaries into Bowman’s space Glomerular capillaries High pressure High permeability to water and small molecules o Large molecules and proteins not permeable Three layers o Capillary endothelium (innermost) fenestrated o Basal lamina o Podocyte pedicels Filtration slits 1/3 of plasma entering glomerular capillary bed filtered into Bowman’s space (Filtration Fraction = 33%) o Reabsorption Movement of molecules out of tubules into peritubular capillaries Carried out by epithelial renal cells lining tubules Polar and multiple carriers Different methods for Conserved solutes o Ex: glucose, amino acids o Goal = 100% reabsorption o Reabsorption of glucose Sodium-Glucose Linked Transporter (SGLT) + Cotransporter (1 glucose: 1 Na ) Takes advantage of Na concentration gradient Secondary active transport Unique to kidneys Glucose Transporter (GLUT) Facilitated diffusion Identical to amino acid reabsorption, but different carriers involved Balanced solutes o Ex: electrolytes o Some reabsorbed, some excreted o 65% reabsorption by cells in proximal tube Without regard to bodily need o Rest of reabsorption in distal tube In accordance to bodily need Regulated by hormones and/or neural influence Na reabsorbed, K secreted Aldosterone increases Na+/K+ exchange Excreted solutes o Ex: urea (waste product of liver), medications o Goal = 100% excretion o Many carriers involved o Secretion Movement of particles out of peritubular capillaries into tubules