1. The Circulatory System
Chapter 15

2. The Cardiorespiratory System
Includes function of the heart, blood vessels, circulation, and gas exchange, between the blood and atmosphere.
Heart pumps blood through the body through pathways (arteries, veins, and capillaries)
Blood is enriched with oxygen when it passes through the lungs
As oxygen enters the bloodstream, carbon dioxide leaves it (respiration)

3. The Circulatory System
Course taken by blood through the arteries, capillaries, and veins & back to heart
Uses blood to transport dissolved materials throughout body
Oxygen, carbon dioxide, nutrients, waste
Picks up waste products of cell metabolism & takes to lungs and kidneys (to be expelled from body)

4. The Heart Two major circulations Location Structure
Each has its own pump
Both pumps are incorporated into the heart
Location
Middle of chest, behind sternum, within ribcage
Pericardial cavity
Above diaphragm
Structure
Primarily a shell with four chambers inside

5. Blood Flow
Two sides of heart are anatomically and functionally separate pumping units
Right side pumps blood through pulmonary circulation
Left side pumps blood through systemic circulation

6. Heart Facts Adult human heart approx size of closed fist
About 5 inches long and 3 ½ inches wide
Weighs just less than 1 pound
Beats about 100,000 times each day
Pump about 8,000 gallons of blood through 12,000 miles of vessels each day
Contracts and relaxes bpm

7. Structure of Heart Four cavities Atria Ventricles
Form curved top of heart
Ventricles
Meet at bottom of heart to form pointed base
Points toward left side of chest

8. Structure of Heart Left Side Right Side One ventricle One atrium
Mitral valve—connects left atrium to left ventricle
One ventricle
One atrium
Tricuspid valve—connects right atrium to right ventricle
valves that prevent blood that flows out of the heart from flowing back in. This system of valves keeps blood moving throught the heart in one direction, like traffic on a one-way street. The one-way flow increases the pumping efficiency of the heart. The valves are so important to heart function that surgeons often attempt to repair or replace a damaged valve.
Wall, septum, separates right and left sides

9. Aorta Pulmonary artery Two largest veins: heart’s main artery
carries blood away from heart to body’s cells
Pulmonary artery
artery that connects heart to lungs
Two largest veins:
Superior vena cava
Inferior vena cava
Two largest veins carry blood inot hear
Called “vena cava” b/c they are the “heart’s veins”

10. As heart contracts, it pushes blood though chambers and into the vessels
Nerves connected to the heart regulate the speed of contractions
Greater the activity, faster the heart will pump; faster heart pumps, more oxygen and nutrient are carried throughout body

11. Heart Muscle
Pericardium
Epicardium
Myocardium
Endocardium

12. Blood Only tissue that flows throughout body
Carries oxygen & nutrients to all parts of body and transports waste products back to lungs, kidneys, and liver for disposal
Essential part of immune system
Crucial for fluid and temperature balance
Hydraulic fluid for certain functions
Highway for hormonal messages
Composed of plasma and billions of cells

13. Plasma The yellowish, liquid part of blood
River in which blood cells travel
Makes up 55% of total volume
Carries blood cells +
Nutrients (sugars, amino acids, fats, salts, minerals)
Waste products (CO2, lactic acid, urea)
Antibodies
Clotting proteins (called clotting factors)
Chemical messengers (hormones)
Proteins that help maintain body’s fluid balance

14. Blood—RBCs & Hemoglobin
Red Blood Cells (erythrocytes)
Highly specialized cells that have been “stripped” of everything, including nucleus
Major job: transporting oxygen
Percentage of RBCs in total blood volume called hematocrit
Hemoglobin
Special red-colored molecule that fills RBCs
Picks up oxygen in areas where O2 is abundant and releases O2 in tissues where O2 concentration lowest

15. Blood—White Blood Cells
5 distinct kinds
Neutrophils, monocytes, lymphocytes, eosinophils, basophils
Able to change according to need and situation in body
Can leave blood stream , sliding out through vessel walls & attacking invaders at site of infections

16. Blood—Platelets
Fragments of much larger cell (megakaryocyte) which stays in bone marrow after it differentiates and matures from stem cell
Platelets leave bone marrow & circulate throughout the body
When stimulated by substance from damaged tissue, platelets release substance to help clot blood

17. Blood Vessels Hollow tubes running throughout the body 5 types
Arteries
Arterioles
Veins
Venules
Capillaries
Provide 2 measurements:
Pulse
Blood pressure

18. Arteries
Blood vessels that carry blood from the heart to organs & cells
Muscular walls that allow them to dilate or constrict
Arterioles: very small arteries
Largest artery=aorta
Runs from chest into abdomen
Receives blood directly from left ventricle

19. Veins Blood vessels that carry blood back to heart Thinner wall
Contain numerous one-way valves (keep blood moving toward heart)
Deep veins in LE surrounded by large muscle groups; compress the deep veins when muscles contract
Contractions in extremities helps propel blood toward heart; increase venous return

20. Veins Largest vein=superior & inferior vena cava
Bring blood from upper and lower body into right atrium
Venules: smallest veins

22. Capillaries
Tiny, microscopic blood vessels that connect arteries to veins
Responsible for transferring oxygen and nutrients to cells
Wall so thin that O2 passes from arterial blood through them into cells in organs/tissues
Waste products (CO2) pass into capillaries to be carried back by veins to heart/lungs

23. Coronary Arteries The heart’s own system of blood vessels
Located around heart muscle to provide blood and oxygen to all parts of heart
Two primary coronary arteries branch off into smaller vessels
Right coronary artery: feeds right atrium & ventricle and bottom of left ventricle
Left main coronary artery: supplies blood to rest of heart
Left anterior descending
Circumflex

24. Heart’s Conduction System
Heart’s electrical system
Consisting of specialized cells within heart muscle that carry an electrical signal
Regulates pumping of heart

25. Blood Pressure
Heart pumps blood into arteries; surge of blood filling vessels creates pressure against vessel walls
Pressure measured by 2 numbers:
Systolic: highest pressure in heart
Correlates to ventricular ctx
Average 120 mm/Hg
Diastolic: lowest pressure in heart
Relates to ventricular ctx
Average 80 mm/Hg
Pulse pressure: difference between diastolic and systolic pressures

26. Pulse Rhythmical beating of heart
Created by alternating expansion and contraction of artery as blood flows through
7 areas where pulse can be felt
Brachial artery
Common carotid artery
Femoral artery
Dorsalis pedis artery
Popliteal artery
Radial artery
Temporal artery

27. Target Heart Rate
Percentage of the maximum heart rate that is safe to reach during exercise
AHA recommends 50-75% for average healthy person
Calculated 220-age
THR is sliding scale that decreases with age
Tool for measuring cardiovascular exercise
Maintain THR for min daily health benefits

28. Flow of Blood through Heart
Superior/inferior vena cava
Right atrium
Tricuspid valve
Right ventricle
Semi-lunar valve
Pulmonary artery
Lungs
1. The right atrium receives deoxygentated blood from the systemic circuit (the body ) through the vena cavae (superior and inferior). 2. Blood flows from the right atrium through the right AV valve ( right atrioventricular valve or tricuspid valve) into the right ventricle. 3. When the right ventricle contracts it pumps blood through the pulmonary semi-lunar valve to enter the pulmonary trunk which starts the pulmonary circuit. valves that prevent blood that flows out of the heart from flowing back in. This system of valves keeps blood moving throught the heart in one direction, like traffic on a one-way street. The one-way flow increases the pumping efficiency of the heart. The valves are so important to heart function that surgeons often attempt to repair or replace a damaged valve. 4. Pulmonary trunk divides into left and right pulmonary arteries. Pulmonary arteries divide smaller and smaller until they deliver blood to gas exchange sites of lungs (alveoli). 5. Once blood is oxygentated it flows back to the heart through the right and left pulmonary veins. 6. Right and left pulmonary veins deliver blood to the left atrium. 7. Blood flows from the left atrium through the left AV valve (aka Mitral or Bicuspid valve) into the left ventricle. 8. Blood is pumped by the strong left ventricle through the aortic semi-lunar valve into the ascending aorta. 9. Blood flows through the aortic arch into the descending aorta.

29. Flow of Blood through Heart
Back to heart via pulmonary vein
Left atrium
Bicuspid valve
Left ventricle
Semi-lunar valve
Aorta
Organs in the body
1. The right atrium receives deoxygentated blood from the systemic circuit (the body ) through the vena cavae (superior and inferior). 2. Blood flows from the right atrium through the right AV valve ( right atrioventricular valve or tricuspid valve) into the right ventricle. 3. When the right ventricle contracts it pumps blood through the pulmonary semi-lunar valve to enter the pulmonary trunk which starts the pulmonary circuit. 4. Pulmonary trunk divides into left and right pulmonary arteries. Pulmonary arteries divide smaller and smaller until they deliver blood to gas exchange sites of lungs (alveoli). 5. Once blood is oxygentated it flows back to the heart through the right and left pulmonary veins. 6. Right and left pulmonary veins deliver blood to the left atrium. 7. Blood flows from the left atrium through the left AV valve (aka Mitral or Bicuspid valve) into the left ventricle. 8. Blood is pumped by the strong left ventricle through the aortic semi-lunar valve into the ascending aorta. 9. Blood flows through the aortic arch into the descending aorta.

30. Flow of Blood through Heart

34. Heart Anatomy

35. Can you label the heart?