1. The Circulatory System
Chapter 12
The Circulatory System

2. Learning Goal
For students to learn more about the function of the circulatory system and its major components
To learn the importance of tools in monitoring the circulatory system

3. Section 12. 1
Functions of Circulation

4. Introduction
The Circulatory system’s role is to transport blood, nutrients, and waste around the body
It’s sort of like the TTC of the body

5. Main Functions of the Circulatory System
It Transports gases (from the Respiratory System), nutrients, and waste materials (from the Digestive System)
It regulates internal temperature and transports chemical substances that are vital to health from 1 part of the body to another
It protects against blood loss from injury and disease-causing microbes, or any toxic substances introduced into the body

6. Major Components of the System
Heart
- Muscular organ that continuously pumps the blood through the body and generates Blood Flow
Blood Vessels
- System of Hollow tubes where blood moves through
Blood
- The Fluid that Transports nutrients, Oxygen, Carbon dioxide, and other things through the body

7. 2 Types of Circulatory Systems
Many invertebrates (no spine) have an Open Circulatory System
Where blood flows freely within the body cavity and makes direct contact with organs and tissues
Other vertebrates (have spine – human) have a Closed Circulatory System
Where the circulating blood is CONTAINED within vessels and kept separate from the interstitial fluid in the body

8. 2 Types of Circulatory Systems

9. The Heart ♥ - Structures
Has 4 Chambers
2 chambers that receive blood from the body or the lungs back into the heart = atria (Right /Left Atrium)
2 chambers that receive blood from the atria and pump blood OUT of the body = ventricles (Right / Left ventricle)

10. 4 Chambers of the Heart - Right Side
The right side RECIEVES blood coming from the body and then pumps this blood out to the lungs
2 large vessels, called the vena cava, open into the Right Atrium
The Superior Vena cava collects oxygen poor (CO2 rich) blood coming from tissues in the head, chest, and arms
The Inferior Vena cava collects oxygen poor blood (CO2 rich) blood coming from tissues everywhere else in the body

11. 4 Chambers of the Heart - Right Side
The oxygen poor blood flows from the Right Atrium into the Right Ventricle, and then out into the pulmonary trunk
From there, it enters into the left and right pulmonary arteries
It then continues into the left and right Lungs for Gas Exchange

12. 4 Chambers of the Heart - Right Side

13. 4 Chambers of the Heart - Left Side
It receives the OXYGEN RICH blood from the Left and Right Lungs and pumps this blood out into the body
The Oxygen-rich blood flows from the lungs through the Pulmonary Veins to the Left Atrium
The left atrium pumps blood into the left ventricle, where all the blood going to the body tissues leave through the LARGEST vessel in the body, the AORTA

14. 4 Chambers of the Heart The valves in the heart are very important
They make sure the blood flows in the correct direction
Checking for Understanding:
What would happen if the blood did not flow in 1 direction?
What consequences would there be?

15. 4 Chambers of the Heart The heart has 4 valves inside of it
The Aorta and ventricles are separated from one another by two valves called Atrioventricular (AV) valves
The AV valve on the Right = Tricuspid Valve (because it is made up of 3 flaps)
The AV valve on the Left = Bicuspid Valve (because it is made up of 2 flaps)

17. 4 Chambers of the Heart
The other 2 valves are called Semilunar Valves because they have a half-moon shape
Where one is within the Aorta
And the other is within the pulmonary artery

19. Path of Blood Flow in ♥
Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart
As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve

20. Path of Blood Flow in ♥
When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts
As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated via gas exchange

21. Path of Blood Flow in ♥
The pulmonary vein empties oxygen-rich blood from the lungs into the left atrium of the heart
As the atrium contracts, blood flows from your left atrium into your left ventricle through the open bicuspid valve

22. Path of Blood Flow in ♥
When the ventricle is full, the bicuspid valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts
As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body

24. Blood Carries out Functions
Humans have approximately 5 Liters of blood moving continuously through the circulatory system
Our blood is made up of:
Plasma (55%) as well as
Cells and cell fragments (45%)

25. Blood & its Components
The blood plasma is made up of mostly water, with small amounts of proteins and other nutrients, oxygen, and carbon dioxide
The cells and cell fragments make up for the solid parts of blood
This consists of mainly red blood cells, some platelets, and some white blood cells

26. Blood & its Components: Use pgs
Blood & its Components: Use pgs. 484 – 485 to summarized the components / functions of blood
Component of Blood
Functions
Plasma

27. Blood & its Components: Use pgs
Blood & its Components: Use pgs. 484 – 485 to summarized the components / functions of blood
Component of Blood
Functions
Red Blood Cells

28. Blood & its Components: Use pgs
Blood & its Components: Use pgs. 484 – 485 to summarized the components / functions of blood
Component of Blood
Functions
White Blood Cells

29. Blood & its Components: Use pgs
Blood & its Components: Use pgs. 484 – 485 to summarized the components / functions of blood
Component of Blood
Functions
Platelets

31. Functions of Blood – Transport
Needs
Wastes
In our body, blood helps with the absorption of nutrients from the digestive system and carries them to needed cells
Blood also picks up chemicals / gases through the respiratory system and carries them to other parts of the body
Blood transports and removes waste products of cellular respiration
Blood also carries excess amounts if mineral ions and other waste products to the kidneys for processing and excretion
Carries Carbon dioxide (CO2) and other waste products of cells to the lungs to be released

32. Functions of Blood – Temperature
Temperature regulation involves balancing the loss of heat from the body with the production of heat made be metabolic processes
A mammal’s circulatory system is able to control heat loss by changing the volume of blood flowing near the body’s surface

33. Functions of Blood – Temperature
Under control of the Nervous System, blood vessels in the skin can
Expand and Dilate to carry more blood via Vasodilation – occurs when core body temp. is too high
Narrow and Constrict to carry less blood via Vasoconstriction – occurs when core body temp. is too low

34. Functions of Blood – Temperature

35. Functions of Blood – Temperature
Vasodilation (↓BP)
Vasoconstriction (↑BP)
Occurs when core of the body becomes hot because of vigorous activity / high external temperature
Releases heat via sweating, where blood flows closer to skin and looses heat via evaporation in sweat
Dilation of blood vessels leads to decreases in blood pressure
Decrease in blood flow and body core temperature
Blood does not flow to extremities as blood vessels contract, stays central to help conserve heat, and reduces the amount of blood flowing near skin
Constriction of blood vessels leads to increases in blood pressure

36. Understanding Blood Vessels
There are 3 main types of blood vessels in the human body
Arteries – carry blood AWAY from the heart
Veins – carry blood TOWARDS the heart
Capillaries – made up of cells that connect arteries and veins

37. Understanding Blood Vessels

38. Understanding Blood Vessels
Artery
Vein
Capillary
Very elastic walls that let the artery expand and contract based on stimuli
The relaxation / contraction of artery walls helps make sure blood flows in the correct direction
Have thinner walls and are not very elastic
Do not contract themselves, but use the surrounding muscle’s contractions to keep blood moving in the correct direction
Have One-Way VALVES that prevent blood from flowing backwards
Smallest blood vessel found in networks within the body
Join the arteries and veins together
Where gases, nutrients, & other materials are transferred from blood to tissues / and tissue cells to blood

39. Checking for Understanding?
Explain why someone going for a routine blood test would want to get blood taken out from a vein vs. an artery or capillary?

40. A Closer Look at the System
The circulatory system is divided into 2 circular pathways
Pulmonary circuit
Systemic circuit

41. A Closer Look at the System
The Pulmonary Circuit
Works by moving blood from the heart to the lungs for gas exchange and back to the heart
The blood carried from the heart to the lings is oxygen-poor (low in # of oxygen)
Carbon dioxide in the blood then collects and moves to the lungs, where gas exchange happens, as CO2 moves out of the blood and fresh new Oxygen (from being breathed in through the lungs) enters into the blood
This exchange of CO2 out and O2 in allows the blood to become enriched with oxygen, which then travels through the blood to the heart to be pumped throughout the body

42. A Closer Look at the System
Systemic Circulation
Works by moving blood from the heart to tissues everywhere in the body
Blood carried from the heart to body tissues comes from the lungs, so its oxygen rich
In the cells of the body tissues, oxygen in the blood is exchanged with carbon dioxide
Where – the oxygen rich blood is pumped in the body, and oxygen poor blood returns to the heart to be pumped into the lungs for gas exchange to happen all over again

43. Section 12.2
Monitoring the Circulatory System

44. Understanding the Heart
Within the heart, a bundle of specialized muscle tissues, called the Sinoatrial (SA) Node stimulate the muscle cells to contract and relax rhythmically
The SA Node is AKA a pacemaker because it sets the pace for cardiac activity

45. Understanding the Heart
The SA node is IN THE WALL of the Right Atrium
It generates an electrical signal that spreads over the 2 atria and makes them contract simultaneously
When the atria contracts, the signal reaches another node, called the Atrioventricular (AV) Node

46. Understanding the Heart
The AV node transmits the electrical signal through the bundle of specialized fibres called the bundle of His
These His fibres that rely the signal through 2 branches that divide into fast-conducting Purkinie Fibres
The Purkinie fibres start the contractions of all cells of the right and left ventricles

47. Understanding the Heart

48. The Heartbeat – “lub – DUB”
Using a stethoscope a medical practitioner can hear the hearts vibrations as it beats
The normal heart sound is a repeated double beat, “lub-DUB” – which reflects different hearts valves closing

49. The Heartbeat – “lub – DUB”
The 1st sound is the closing of the AV valve, as blood is pumped from the atria to the ventricles
The 2nd sound is the closing of the semilunar valves, as blood is pumped from the ventricles into the arteries

50. The Heartbeat – “lub – DUB”
Differences in normal heart beats can indicate a problem
Example – a heart murmur occurs when blood doesn’t flow smoothly into the heart either due to the narrowing of heart vales / arteries or when a valve doesn’t close properly and backflow of blood happens

51. The Heartbeat – “lub – DUB”

52. The Electrocardiogram – ECG
Electrical pulses that make the heart to beat create small voltage charges that can be measured through the use of putting electrodes on the skin of the chest
These voltage measurements produce an ECG that doctors use to diagnose the health of the heart

53. The Electrocardiogram – ECG
“LUB”
“DUB”

54. Blood Pressure - BP
As blood passes through vessels in the body, it exerts pressure against the vessel walls = Blood Pressure (BP)
Changes in BP reflect phases of the heartbeat
When the ventricles contract and force blood into the pulmonary arteries and the aorta, the pressure ↑
The maximum pressure during the ventricular contraction = systolic pressure
When the ventricles relax, the pressure in the pulmonary arteries and aorta ↓
The lowest pressure before the ventricle contracts = diastolic pressure

55. Blood Pressure - BP

56. Measuring Blood Pressure
Many doctors measure blood pressure to check the health of the circulatory system
BP reading shows how much pressure the blood exerts against the vessel walls and indicates the condition of the heart and arteries
Often a sphygmomanometer (blood pressure cuff) is used with a stethoscope to hear the flow of blood as pressure from the sphygmomanometer is released

57. Measuring Blood Pressure
When BP reading is taken, its measured its recorded in mL of mercury (Hg)
Read – Systolic pressure over Diastolic pressure

58. Checking for Understanding
How does exercise help blood pressure?
What would a blood pressure reading of 150 over 93 indicate?
Using your previous knowledge and pg. 491 identify 2 causes that contribute to high blood pressure. Describe ways to help lower BP.

59. Cardiac Output & Stroke Volume
The amount of blood pumped by the heart = Cardiac Output
Cardiac Output is an indicator of the level of Oxygen delivered to the body (reflects amount of work done by muscles in body)
2 factors contribute to Cardiac Output:
Heart Rate = # of beats per minute
Stroke Volume = # of blood forced out of the heart per heart beat (

60. Cardiovascular Fitness
Defined as:
the capacity of the heart, lungs, and blood vessels to deliver oxygen to working muscle tissues so they can maintain prolonged physical work

61. Cardiovascular Fitness
Cardiovascular exercises like running provide health benefits by:
Enlarging the ventricles
Increasing elasticity of the heart muscles
Strengthening ventricle walls
These all contribute to an ↑ stroke volume
Another indicator is the length it takes the heart to recover to resting HR after exercise (more fit = less time to recover)