Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Lecture 17, 28 Oct 2003Chapter 12, Circulation (con’t)Vertebrate PhysiologyECOL 437University of ArizonaFall 2003instr: Kevin Boninet.a.: Bret Pasch1Vertebrate Physiology 4371. Circulation (CH12)2. Announcements exams Wed Seminar Assgt.3. Slide #sSherwood 199722003 Vertebrate PhysiologyEXAM 2, 21 October 200300.511.522.533.506121824303642485460667278849096Score out of 100# of studentsmean 76.8625max 94.25min 47.25s.d. 14.29333n=203ANATOMY: The integument has a unique circulatory pattern that involves a shunting system through the reticular layer into the subcutaneous layer. This cutaneous plexus gives off tributaries to supply the adipose tissue of the subcutaneous layer and the tissues of the integument. As the cutaneous plexus approaches the papillary layer they terminate in the capillaries of the dermal papillae. These branches supply the hair follicles, sweat glands, and other structures in the dermis. The unusual thing about these capillaries is that the small arteries and arterioles that supply them are organized into another interconnecting system call the papillary plexus. The papillary plexus provides arterial blood to the capillary loops that follow the contours of the dermal papilla at the epidermal-dermal boundary to feed the structures mentioned above. The venous network returns the blood back to the body core by following the arterial pattern exactly. Once you have the anatomy under control they the physiology follows from the structure of the blood flow pattern.PHYSIOLOGY: When the skin is challenged by cold, the first thing that happens is the smooth muscle surrounding the small arteries and arterioles going from the cutaneous plexus through the reticular layer to the papillary plexus constrict to conserve body heat. This action shunts the blood away from the reticular and papillary layers and keeps it in the deeper subcutaneous layers. Just the opposite happens when a person gets over-heated, along with sweating, to reduce body heat. In that case the warm blood from the deeper layer is shunted into, rather than away from, the papillary layer so that the cooling effect of evaporating sweat will be maximized as the warm blood passes through the cooler dermal capillary loops before going into the venous tree. Something fascinating happens in the cold response, however. Since tissue will die without having oxygen and nutrients delivered and waste products removed over time, the shunting mechanism cannot shut down indefinitely. Depending on how cold the area of skin gets, the smooth muscle will reduce its contraction every so often. This will occur at 5 to 15 minute intervals, as I said depending on the degree of cold on that particular skin surface. Some people have inappropriate spasms of the smooth muscle that greatly restrict the flow to the dermis and then, after a severe cold period that can become painful, the vessels will dilate much more than normal and cause the skin to be a bright pink or red. This phenomenon is most common in the digits of hands and feet and is most frequently found in young women. The case is unknown (idiopathic). The person can actually have a triphasic color change starting with pallor (shutting down of the blood flow), moving to cyanosis (bluish color due to reduction of oxygen and build up of carbon dioxide), and then reactive hyperemia (redness). This problem was described by a doctor named Raynaud and is now referred to as Raynaud’s disease.3bCold, red skin?Name that student:Lauren MashaudCricket researchLinda WebbPsychologySarju_GovaniDines at DD4Recall AP and refractory period differences…(12-7)5Vander 2001(see 12-5)Types of Cardiac Cells:A. ContractileB. Conducting~ autorhythmic~ fast-conductingSA nodeAV nodeInternodalInteratrialBundle of HisPurkinjeEtc.6Sherwood 19977Types of Cardiac Cells:A. ContractileB. Conducting- 1 autorhythmic-1 fast-conductingSA nodeAV nodePacemakers:-Normally HR driven by SA node-Others are Latent pacemakers-Called Ectopic pacemaker when node other than SA driving HRInternodalInteratrialBundle of HisPurkinjeEtc.8Sherwood 1997~ SA node~ latent rateSherwood 19979Sherwood 1997SAAVotherThe Heart Rate Train10oops9-11, Sherwood 1997Autorhythmic Cardiac Muscle (e.g. SA node)~Transient Ca2+ channelsK+, Na+Which way would you alter channel permeabilities to speed or slow HR??11Sherwood 1997Vander 2001Contractile Cardiac MuscleCa2+ current maintains plateau12(12-8)(Q,R,S masks atrial repolarization)13(12-8)1414-25, Vander 2001(See 12-12)Wiggers DiagramValves open/close where pressure curves cross760 mmHg = 1 atm = 9.8 m blood1:215Sherwood 1997Atrial KickHeart filled ~same with increased HR16Sherwood 1997Vander 2001Frank-Starling Curve (p. 483)Systole = Ventricular EmptyingDiastole = Ventricular Filling (rest)17(12-13)Heart Work Loops18Cardiac Output:CO = cardiac output (ml/min from 1 ventricle) SV = stroke volume (ml/beat from 1 ventricle) = EDV – ESV (end-diastolic – end-systolic volume)HR = heart rate (beats/min)CO = HR x SV- Heart can utilize different types of energy sources (unlike brain)18bMABP = CO x TPRMABP = DP + 1/3(SP-DP)HR controlParasympathetic vs. Sympathetic(12-5)19(12-6)20Cardiac Output ControlSympathetic speeds heart rateand increases contractility1. Norepinephrine binds to beta1 adrenergic receptors2. Increases cAMP levels and phosphorylation3. Activates cation channels (Na+) and increases HR4. Epi and Norepi activate alpha and beta1 adrenoreceptors which increase contractility and rate of signal conduction across heart21Vander 2001How increase contractility?More Ca2+22HR controlParasympathetic slows heart rate-Innervate Atria (Vagus nerve = Xth cranial nerve)-Cholinergic (ACh)-Alter SA node pacemaker potential by  K+ permeability  Ca2+ permeabilityParasympathetic innervation of AV node slows passage of signal between atria and ventricles23Hemodynamics in VesselsVander 200114-11, Vander 2001Flow depends primarily on pressure gradient and resistance24Hemodynamics- Poiseuille’s Law:Flow rate8L Q = (P1 – P2)r4Pressure Gradientradius4lengthviscosityUse to approximate flowSmall change in radius  large change in flow rate25Hemodynamics- From Poiseuille’s Law:ResistanceQ R = (P1 – P2)Pressure Gradientradius4Flow