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CARDIOVASCULAR FUNCTION IN Rana pipiens. Biology 305 Laboratory. ANNOUNCEMENTS. BIOL305L MIDTERM GRADE DISTRIBUTION. A = 90 – 100% B = 80 – 89% C = 70 – 79% D = 60 – 69% F = Below 60%. ANNOUNCEMENTS. MIDTERM Request for Regrades Handled by me You can LOOSE points!
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CARDIOVASCULAR FUNCTION IN Rana pipiens Biology 305 Laboratory
ANNOUNCEMENTS BIOL305L MIDTERM GRADE DISTRIBUTION A = 90 – 100% B = 80 – 89% C = 70 – 79% D = 60 – 69% F = Below 60%
ANNOUNCEMENTS • MIDTERM • Request for Regrades • Handled by me • You can LOOSE points! • Request for Regrade Form is REQUIRED • Must be specific to particular question • No exams in pencil will be regraded • Deadline = one week after exam is turned back • Please turn in at start of your lab • Please do not disturb me in my office!
ANNOUNCEMENTS • Lab Report #2: • Based on next lab! • Researched and written INDIVIDUALLY • Plagiarism = 0 + academic penalties! • Take notes and record all data during lab • Outline will be given out next week • Two scientific journal articles required as references • Turnitin.com
ANNOUNCEMENTS Lab Quiz Next Week: • Based on: • Virtual Mouse Respiration Lab • Frog Cardiovascular Lab
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE The Virtual Mouse Respiration Lab: • A Test of Rubner’s Surface Rule • Applies to endotherms • “Warm-blooded animals” • Regulate body temp & generate heat through metabolism
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE What We Know: • As a sphere increases in size: • Volume(V) grows proportional to theraduis3 • Surface area (SA) grows proportional to the radius2 • Therefore SA is related to V to the power 2/3 or 0.67
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE Rubners Surface Rule: • Assuming an animal is a sphere, small animals have less volume per unit SA than their larger counterparts • Cells in smaller endotherms have a higher metabolic rate to compensate for a greater amount of heat lost across the surface of their bodies
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE The Virtual Mouse Respiration Lab: • Results: • Lg mouse consumes more O2/min • Higher overall metabolic rate
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE The Virtual Mouse Respiration Lab: Results: • Sm mouse consumes more O2/min/gm • Higher massspecific metabolic rate • Same trend found for all mammals • Mass specific metabolic rate declines as body mass increases
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE The Virtual Mouse Respiration Lab: • Rubner’s Surface Rule: • Gives incomplete explanation! • Slope = 0.75 instead of theoretical value of 0.63 • Mass specific metabolic rate in ectotherms indicates same trend • Scientists not entirely clear why differences are observed
THIS WEEK’S EXERCISE: VIRTUAL MOUSE EXERCISE The Virtual Mouse Respiration Lab: • What Scientists Know About Small Animals: • They have relatively high respiratory + heart rate • Their Hemoglobin (Hb) is relatively concentrated • Hb-O2 Curve is R-shifted at tissues: • Hb has lower affinity more O2 released • They have high mitochondrial densities, surface area & enzyme activity • They have relatively high capillary density
NEXT WEEK’S EXERCISE: FROG CARDIOVASCULAR PHYSIOLOGY The CV System: • CV system tied to respiratory system • Functions in gas exchange & transport of nutrients and waste products
FROG CARDIOVASCULAR PHYSIOLOGY Three Main Components: • Heart • Muscular organ that pumps blood through body • Blood • Fluid (connective tissue) • Vessels • Tubes for directing blood transport
FROG CARDIOVASCULAR PHYSIOLOGY The Heart: • Primarily functions to provide pressure to move blood to its ultimate destination: • The tissues
EVOLUTION OF THE VERTEBRATE HEART Fish & Mammals: • Two Extremes in Vertebrate Circulation • A gradual separation of heart into TWO SEPARATE PUMPS • occurred as vertebrates progressed from aquatic to terrestrial respiration
EVOLUTION OF THE VERTEBRATE HEART Fish: • Heart has two chambers • One circuit • No Pulmonary Circuit • One cardiac cycle: • Blood p/u O2 in gills • O2 delivered to tissues • O2 -poor blood returns to heart
EVOLUTION OF THE VERTEBRATE HEART Amphibian: • Heart has three chambers • One ventricle • Two partially separate circuits • One cardiac cycle • O2-deficient blood enters heart • May mix with O2-rich blood from lungs • Blood pumped out of heart to rest of body
EVOLUTION OF THE VERTEBRATE HEART Birds & Mammals: • Heart has 4 separate chambers • Two atria • Two ventricles • Two separate circuits • Systemic circuit • Pulmonary circuit • O2-rich and O2-deficient blood do NOT mix
ANATOMICAL FEATURES OF THE AMPHIBIAN HEART Sinus Venosus: • Region of pacemaker cells between vena cava and right atrium • Sinoatrial node (SA) in mammals probably evolved from SV
CARDIOVASCULAR PHYSIOLOGY Frog Heart Consists of Two Types of Cells: • Myocardial AutorhythmicCells • Initiate rhythmic contractions w/o external stimulation (myogenic) • Set pace of the heartbeat • Myocardial Contractile Cells • Contract in response to depolarization • Push blood into vessels tissues
CARDIOVASCULAR PHYSIOLOGY • Some Terms to Know: • Cardiac Output • Heart Rate • Stroke Volume • Contractility • Systole • Diastole • Ventricle • Atria
CARDIAC OUTPUT Cardiac Output (CO) • Measure of amount of blood pumped from the heart per unit time • Units = ml/min CO = HR * SV
HEART RATE Heart Rate (HR) • The number of contractions per unit time • Units = bpm
STROKE VOLUME Stroke Volume (SV): • Volume of blood ejected from heart during ventricular contraction • Units = mL
CONTRACTILITY Contractility: • Intrinsic ability of a cardiac muscle fiber to contract at a given length
STARLING’S LAW OF THE HEART Stroke Volume As A Function of EDV ^ Stroke Volume (ml) or Force of Contraction Normal * End Diastolic Volume (ml) Stretch of Myocardial Cells Causes Greater Force of Contraction (& SV) ^ Some chemical agents can affect contractile force irrespective of level of stretch
CARDIOVASCULAR PHYSIOLOGY • Regulation of Heart Rate and Force of Contraction Represents a Balance: • Intrinsic Factors • Extrinsic Factors
CARDIOVASCULAR PHYSIOLOGY • Intrinsic & Extrinsic Factors: • Autonomic Nervous System • Sympathetic Discharge (NE) • Parasympathetic Discharge (Ach) • Endocrine System • Hormones (Epi & NE) • Drugs • Agonists & Antagonists • Temperature
PRIMARY AUTONOMIC NEUROTRANSMITTERS (NT) • Acetylcholine (Ach): • Main NT of the parasympathetic division • Binds to cholinergic receptors • Norepinephrine (NE): • Main NT of the sympathetic division • Binds to adrenergic receptors
CARDIOVASCULAR PHYSIOLOGY Purpose of Next Weeks Lab: • Determine effect of both intrinsic & extrinsic factors on CO, HR and Force of Contraction. • Determine to what extent Starlings Law applies to the frog heart