Circulatory System Professor Andrea Garrison Biology 11 Illustrations ©2010 Pearson Education, Inc. unless otherwise noted Circulatory System1

Circulatory system = Cardiovascular system = heart, blood vessels & blood Circulatory System2

Function = homeostasis – Transport O 2 /CO 2 Food/wastes Fluids Hormones – Regulate pH Water balance Temperature – Immune defense Circulatory System3

Blood ~ 5 liters in adult – Plasma – Cellular elements Circulatory System4

Blood Plasma – ~ 55% of blood volume – 90% water – 10% solutes Blood proteins Nutrients Wastes Gases Hormones Circulatory System5

Blood Cellular elements – ~ 45% of blood volume Circulatory System6

Blood Red blood cells – 5 million/cc (=ml) – Carry O 2 – Produced in bone marrow – Biconcave – No nucleus – Live ~ 120 days Circulatory System7

Blood White blood cells – 4,000 – 11,000/cc – Protection from disease – Produced in bone marrow – Have nucleus – Long-lived Circulatory System8

Blood Platelets – 200,000 – 400,000/cc – Form blood clots – Produced in bone marrow – Cell fragments Circulatory System9

Heart Pumps blood to body’s cells Circulatory System National Heart Lung Blood Institute, 10

Heart Anatomy Circulatory System; From Wikimedia Commons, Diagram of the human heart, created by Wapcaplet in Sodipodi. Cropped by Yaddah to remove white space (this cropping is not the same as Wapcaplet's original crop).WapcapletYaddah 11

Heart Anatomy 4 chambers – 2 atria – 2 ventricles Valves – Atrioventricular (AV) valves – Semilunar valves Circulatory System; modified from National Cancer Institute, NIH, 12 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart Anatomy 4 chambers – 2 atria Receive blood – 2 ventricles Pump blood out of heart Circulatory System; modified from National Cancer Institute, NIH, 13 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart Anatomy Valves – Prevent backwards flow of blood Circulatory System; modified from National Cancer Institute, NIH, 14 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart – Double Circuit Circulatory System15

Blood Vessels Arteries carry blood away from heart Veins return blood to heart Capillaries in between – Every organ has its own capillary network Circulatory System16

Blood Vessels Circulatory System17

Blood Vessels Capillaries – Gas and nutrient exchange – Very small vessels – Walls one cell thick Effective diffusion – Narrow lumen One cell at a time Effective diffusion Circulatory System18

Blood Vessels Capillaries – Gas and nutrient exchange – Very small vessels – Walls one cell thick Effective diffusion – Narrow lumen One cell at a time Effective diffusion Circulatory System19

Blood Circuit artery arteriole heart capillaries vein venule Circulatory System20

Double Circuit Circulatory System21

Heart Anatomy Circulatory System; modified from National Cancer Institute, NIH, 22 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Blood Flow through the Heart Circulatory System23

Blood Flow through Heart Circulatory System24

Blood Flow through Heart Circulatory System25

Blood Flow through Heart Circulatory System26

Blood Flow through Heart Circulatory System27

Blood Flow through Heart Circulatory System28

Blood Flow through Heart Circulatory System29

Blood Flow through Heart Circulatory System30

Blood Flow through Heart Circulatory System31

Blood Flow through Heart Circulatory System32

Blood Flow through Heart Circulatory System33

Blood Flow through Heart Circulatory System34

Heartbeat Intrinsic to heart muscle Regulated by sinoatrial node (pacemaker) – Its own intrinsic rate of beating – Sends electric impulses so all cells beat w/it – Involuntary nervous system ↑ or ↓ heart rate Circulatory System35

Heartbeat Circulatory System36

Heartbeat Circulatory System37

Heart Rate Resting heart rate bpm (~ 72 bpm healthy non-athlete) Heart alternates between contraction and relaxation – Contraction = systole – Relaxation = diastole Circulatory System38

Cardiac Cycle Circulatory System39

Cardiac Cycle Circulatory System40

Cardiac Cycle Circulatory System41

Heart Valves Open when P behind > P in front Close when P in front > P behind Circulatory System; modified from National Cancer Institute, NIH, 42 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart Valves Healthy valves insure one-way flow – Tendons attach AV valves to ventricle wall – Semilunar valves have little pressure in front Circulatory System; modified from National Cancer Institute, NIH, 43 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart Valves Damaged valves – Allow backflow – Cause heart murmur Circulatory System; modified from National Cancer Institute, NIH, 44 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Heart Valves Make heart sounds when they close – Healthy sounds – Heart murmur Circulatory System; modified from National Cancer Institute, NIH, 45 Right AV valve Left AV valve Right semilunar valve Left semilunar valve

Blood Flow through Vessels Systole – Ventricles contract – Blood leaves heart via arteries – Arterial pressure ↑ Diastole – Ventricles relax – Arterial pressure ↓ Blood flow surges in arteries Circulatory System46

Blood Flow through Vessels Side note: – Blood pressure Systolic pressure during systole Diastolic pressure during diastole Systolic P/diastolic P – Average <120/<80 – High 140/90 or greater Circulatory System47

Blood Flow through Vessels Surging and pressure ↓ with distance from heart No difference in pressure in capillaries and veins during systole and diastole Blood flow smooth in capillaries and veins Circulatory System48

Blood Flow through Vessels Blood pressure lowest in veins Heartbeat cannot return blood to the heart Venous return depends on other mechanisms – Skeletal milking – Respiratory pumping Circulatory System49

Return of Blood through Veins Skeletal milking – Functions in arms and legs – Muscle contraction around veins squeezes blood towards heart – Veins have one-way valves – Blood is “milked” towards torso Circulatory System50

Return of Blood through Veins Respiratory pumping – Inhalation decreases pressure around heart Sucks blood through abdominal and chest cavities toward heart Circulatory System51

Return of Blood through Veins Respiratory pumping – Inhalation decreases pressure around heart Sucks blood through abdominal and chest cavities toward heart Circulatory System52

Vasodilation/Vasoconstriction Blood vessels can dilate or constrict – Involuntary nervous system Controls blood pressure Fight or flight response – Local tissue control Constrict to ↓ blood flow – in cold weather to avoid heat loss Dilate to ↑ blood flow – in warm weather to cool off – For healing of injured tissues Circulatory System53

Cardiovascular Disease Diseases of the heart and blood vessels Kill over 1 million people in US each year Circulatory System54

Atherosclerosis Circulatory System55

Coronary Artery Disease Circulatory System56

Cerebral Vascular Disease Stroke – Blockage of blood vessel in brain Blood clot or fatty deposits – Bleeding blood vessel in brain Rupture due to weak vessel wall or high blood pressure Circulatory System57

Peripheral Artery Disease Blockage of blood vessels in legs – ↓ blood flow to legs and feet – Pain in legs when walking – Greater risk of heart attack/stroke Circulatory System58

Hypertension High blood pressure – Can harden arteries ↓ blood flow to heart – Chest pain – Heart failure—inability of heart to pump enough blood to organs Can rupture blood vessels – Stroke – Kidney damage Circulatory System59

Heart Health Don’t smoke Exercise regularly Maintain a healthy weight Healthy diet – Low in saturated fats – No trans fats – Low cholesterol – Low sodium – High fiber (lowers cholesterol) Circulatory System60