1 Biology 102 Laboratory 7 Microcirculation

2 Objectives for Lab 7 List the components of the microcirculatory system and their functions. Identify arterioles, venules, and capillaries in a goldfish tail under a dissecting microscope and estimate the diameters of the vessels. Observe and explain the effect of the various substances used in lab on the vessels in the goldfish tail, i.e., vasodilation or vasoconstriction Explain WHY vasodilation or vasoconstriction occurred.

3 Review of Blood Vessels Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007 Microcirculation

4 Arteriole smallest arterioles only have a few smooth muscle fibers can vasoconstrict (decrease diameter) or vasodilate (increase diameter) Most important in controlling blood flow to capillary beds Arterioles are specialized for controlling blood flow into capillary beds Figure from: Hole’s Human A&P, 12 th edition, 2010

5 Metarterioles Each metarteriole supplies about capillary beds Metarterioles form arteriovenous shunts that can bypass capillary beds Figure from: Hole’s Human A&P, 12 th edition, 2010

6 Capillaries smallest diameter blood vessels (fit 1 RBC at a time) extensions of inner lining of arterioles walls consist of endothelium and basement membrane only – NO smooth muscle semipermeable (plasma fluid can escape, but not proteins) 3 types: - continuous (muscle) - fenestrated (endocrine glands, kidney, small intestine) - sinusoids (liver, spleen, bone marrow) Figure from: Hole’s Human A&P, 12 th edition, 2010

7 Capillary Network Blood can follow different pathways through metabolically active/inactive tissues Figures from: Hole’s Human A&P, 12 th edition, 2010

8 Regulation of Capillary Blood Flow Precapillary sphincters may close a capillary respond to needs of the cells low oxygen and nutrients cause sphincter to relax Figure from: Hole’s Human A&P, 12 th edition, 2010

9 Venules and Veins Venule thinner wall than arteriole; larger lumen less smooth muscle and elastic tissue than arteriole Vein thinner wall than artery; larger lumen three layers to wall but middle layer is poorly developed some have flaplike valves carries blood under relatively low pressure serves as blood reservoir are able to constrict (sympathetic innervation)

10 Things you should do in lab today Obtain/Prepare a goldfish as described in the Lab Guide/Handout Instructions (work in groups of four) Observe and identify the arterioles, capillaries, and venules in the goldfish tail under the compound light microscope before doing any experimental treatments. (Remember that the compound scope will REVERSE things so be careful to correctly ID vessels) –Take note of the normal vessel diameter in each type of vessel and record their approximate diameter (what can you use as a handy guide?) –Note the manner in which blood flows through the different vessels and record your observations –Record all observations on your lab report sheet Apply the treatments –Record your observations in the table in your lab report handout –Be sure to think about WHY you saw the reactions you observed –You do NOT have to hand in your Lab Report sheet – but remember, you will have to know this material for Lab Exam 1. After all groups have finished, we’ll review the results

11 Next… After you do this lab today… –We will review last week’s results –Lab Exam 1; format/content Review Exercises 36 & 37 in Marieb’s Lab Manual in preparation for looking at respiratory system anatomy

12 Review of Subjects for Lab Exam 1 Lab Exam 1 will consist of stations and approximately 65 fill-in-the- blank questions. You will be expected to be able to recognize all structures listed in your Laboratory Guide and know the items listed on this study guide. Remember that SPLLEING COUTNS!! You will lose 1 point for every 2 spelling errors you make. For help in studying the following items and getting practice, be sure to look at the following items in the Laboratory Section of the gserianne.com Web site 1. The online PowerPoint Quizzes 2. The 'Links to Explore' (if available) for each topic.

13 Review of Subjects for Lab Exam 1 Blood (Lab 1) - approximately 9 questions –Know how to read a blood typing card (agglutination reaction) and determine blood type from what you see –Understand what determines blood type and under what circumstances a transfusion reaction may occur, i.e., what serum antibodies must be present for a reaction to take place –Be able to distinguish the different types of leukocytes under the microscope or given a photomicrograph, and know the approximate percentage of neutrophils, lymphocytes, and monocytes Heart (Lab 2) – approximately 8 questions –Using the heart models or photographs of hearts, be able to recognize ALL the structures on the checklist in your Laboratory Guide –Explain what is responsible for the first (S1) and second (S2) heart sounds?

14 Review of Subjects for Lab Exam1 Blood vessels (Labs 3, 4, and 5) – approx. 20 questions (12 human, 8 cat) –Given a histological slide or photomicrograph, identify the vessel as either an artery or vein, and be able to identify the layers of the vessel. –Be able to identify the human or cat arteries and/or veins shown in your Guides for Laboratories 3 through 5. I may use human models/photographs/diagrams, cats, or photographs of cats. –Be able to trace the path of a drop of blood from any starting point in the body to any ending location (using only the blood vessels/heart structures for which you are responsible). Blood Pressure (BP) (Lab 6)- approximately 6 questions –Identify, and correctly spell, the standard equipment used to determine blood pressure (BP). –Calculate: 1) Pulse Pressure and 2) Mean Arterial Pressure (MAP) –Predict the physiological effects of body position and exercise on BP.

15 Review of Subjects for Lab Exam 1 Electrocardiogram (ECG) (Lab 6) – cont’d; approx. 4 questions –Recognize/label: a. The P, QRS, and T waves of an EKG b. The P-R and Q-T intervals –Explain the meaning of each of the waves and intervals in the EKG –Recall the normal times/time ranges for the: PR, QT, and QRS intervals –Calculate the heart rate given an EKG tracing and a time interval between –two or more heartbeats (see Lab Guide 6 for an example). Microcirculation (Lab 7) – approx. 6 questions –List the components (vessels) of the microcirculatory system and their functions. –Predict the effect of the various substances on the vessels in the goldfish tail, i.e., vasodilation or vasoconstriction

16 After our Lab Exam… We will do the Respiratory portion of the Lecture Exam 2 Review. (Slides are posted online)