Larry M. Frolich, Ph.D. Biology Department, Yavapai College Blood everywhere— capillaries Oxygen for Cell Respiration Circulatory System –Blood Cells –Arteries and veins –Heart and Chambers Blood, Oxygen and Circulation

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Blood is everywhere…how? Circulatory system –Big vessels leave from pump—heart –Divide and split to all major parts of body: Limbs Head Guts Major organs Body wall Skeleton, muscles

Larry M. Frolich, Ph.D. Biology Department, Yavapai College “Stuff” moves in and out of blood From/to outside world –O2, CO2 in lungs –Nutrients in guts/digestive system –metabolic wastes— kidneys/urinary system From/To cells of body –Every single tissue –O2, CO2, nutrients, waste

Larry M. Frolich, Ph.D. Biology Department, Yavapai College “Stuff” moves in and out by diffusion Inside organs, muscles, structures, bones, big vessels divide into smaller and smaller vessels and then into network-like capillary beds. This is where diffusion can happen rapidly, at the microscopic level. Then, to get blood back to heart, capillaries feed into smaller veins into larger and larger veins into major veins that return to heart

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Capillaries infiltrate every tissue of the body (so blood is everywhere!) Why? Because the cells that make up every tissue need –Oxygen (for cellular respiration) –Nutrients (for cell metabolism) –Immune cells nearby (to eliminate invading microbes) –Removal of waste (from cell metabolism)

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Capillaries—schematic view Very schematic view of what happens in a capillary Arteries bring blood from heart. Veins take blood to heart. Network of capillaries really connects artery to vein Diffusion of needed substances only happens in microscope, thin-walled capillaries See next slide for more realistic view of capillary network or “capillary bed.”

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Capillaries—more realistic views More realistic drawing showing network of capillaries connecting arteries to veins and threading through tissue. Open-ended lymph capillaries pick up excess fluid from tissue and also give immune cells route back into blood circulation Photomicrograph of stained blood vessels of retina showing intricate capillary network Electron micrograph showing arterioles, tiniest of arteries, splitting into virtual sheet of capillary network that brings blood into very close proximity with almost every cell in the tissue.

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart pumps blood If more oxygen is needed, heart pumps faster Brain, guts are big users of oxygen But muscles under physical activity are biggest user. During exercise, more muscles are active, more oxygen is needed so heart pumps faster Pulse is measure of how fast heart is pumping Learn to measure your own pulse—you’ll need to do this for the Lab Project

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Blood Pressure Blood pressure measures force of blood against wall of vessels Systolic pressure is highest point, as blood is being forced out of heart by contraction of heart muscle Diastolic pressure is lowest point, between heart “beats,” when heart is inactive Would you expect these values to be affected by physical exercise—find out in Lab Project for this unit!

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Why do cells need oxygen? Remember Cell Respiration (breaks down glucose to make high-energy ATP bonds that can be used for cell metabolic reactions) –Glycolysis (can happen in absence of oxygen=fermentation) –Citric acid cycle –Electron transport chain

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Every step of respiration catalyzed by proteins that are coded for in the DNA Can you find cellular respiration on the E. coli metabolic map?

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Oxygen diffuses into blood in lungs In lungs, bronchioles (air tubes) branch and branch, finally ending in tiny sacs called alveoli. Each alveolus is surrounded by capillaries Oxygen diffuses across super-thin epithelial tissue of alveolus, across super-thin epithelial tissue of capillary, across red blood cell membrane and is held by Hemoglobin protein molecules in red blood cells How does oxygen get into blood?

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Blood Cells Red blood cells are one of several types of blood cells Each second, 3 million new red blood cells are formed by a special kind of mitosis Red blood cells have no nucleus or organelles. They are just full of Hemoglobin (Hb) Thus, Hb was one of the earliest proteins to be isolated and understood. It’s role in sickle cell anemia also helped to unlock the genetics and molecular structure of Hemoglobin (see web links on the course website)

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Blood Cells White blood cells fight invading microbes as part of the immune system Include –Lymphocytes—recognize invaders –Monocytes and neutrophils—actually consume or engulf microbes –Basophils—release substances that trigger the other cells.

Larry M. Frolich, Ph.D. Biology Department, Yavapai College What Does C-V System do? Circulate blood throughout entire body for –Transport of oxygen to cells –Transport of CO2 away from cells –Transport of nutrients (glucose) to cells –Movement of immune system components (cells, antibodies) –Transport of endocrine gland secretions

Larry M. Frolich, Ph.D. Biology Department, Yavapai College How does it do it? Heart is pump Arteries and veins are main tubes (plumbing) –Arteries Away from Heart –Veins to Heart Diffusion happens in capillaries (oxygen, CO2, glucose diffuse in or out of blood)

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart/Great Vessels-- 1 Route Smaller aa. vv.--many routes (collateral circulation) Capillaries—network where diffusion occurs Overall Organization of System

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Artery/Vein differences Arteries (aa.)Veins (vv.) Direction of flow Blood Away from Heart Blood to Heart PressureHigherLower WallsTHICKER: Tunica media thicker than tunica externa THINNER: Tunica externa thicker than tunica media LumenSmallerLarger ValvesNo valvesValves (see next)

Larry M. Frolich, Ph.D. Biology Department, Yavapai College

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Capillaries Microscopic--one cell layer thick Network Bathed in extracellular matrix of areolar tissue Entire goal of C-V system is to get blood into capillaries where diffusion takes place

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Two circulatory paths Pulmonary Systemic

Larry M. Frolich, Ph.D. Biology Department, Yavapai College GREAT VESSELS Aorta IVC, SVC Pulmonary Trunk Pulmonary Veins

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart Chambers and Valves

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart Chambers and Valves

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart Chambers Right Atrium (forms most of posterior of heart) –Receives O 2 -poor blood from body via IVC, SVC, Coronary sinus –Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale Right Ventricle –Receives O 2 -poor blood from right atrium through tricuspid valve –Pumps blood to lungs via Pulmonary Semilunar Valve in pulmonary trunk Left Atrium –Receives O 2 -rich blood from 4 Pulmonary Veins Left Ventricle (forms apex of heart) –Receives blood from Left Atrium via bicuspid valve –Pumps blood into aorta via Aortic Semilunar Valve to bod

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Heart Valves: Lub*-Dub** *Tricuspid Valve: Right AV valve –3 Cusps (flaps) made of endocardium and CT –Cusps anchored in Rt. Ventricle by Chordae Tendinae –Chordae Tendinae prevent inversion of cusps into atrium –Flow of blood pushes cusps open –When ventricle in diastole (relaxed), cusps hang limp in ventricle –Ventricular contraction increases pressure and forces cusps closed *Bicuspid (Mitral) Valve: Left AV valve –2 cusps anchored in Lft. Ventricle by chordae tendinae –Functions same as Rt. AV valve **Semilunar valves: prevents backflow in large arteries –Pulmonary Semilunar Valve: Rt Ventricle and Pulmonary Trunk –Aortic Semilunar Valve: Left Ventricle and Aorta –3 cusps: blood rushes past they’re flattened, as it settles they’re pushed down (valve closed)

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Another View

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Location of Heart in Thorax

Larry M. Frolich, Ph.D. Biology Department, Yavapai College Fetal Circulation No circulation to lungs Foramen ovale Ductus arteriosum Circulation must go to placenta Umbilical aa., vv.