Learning Objectives
Benchmark: SC. 912.L.14.36
Learning Objectives:
Learning Objectives:
- Students will identify factors that affect blood flow and/or describe how these factors affect blood flow through the cardiovascular system. Items may address factors such as blood pressure, blood volume, resistance, disease, and exercise.
- Students will be able to diagram blood flow of oxygenated and deoxygenated blood through the heart, lungs, and body.
- Students will be able to explain the relationship between pressure, resistance, and blood flow.
- Students will be able to describe various diseases related to the cardiovascular system.
Lectures
POWER POINT LECTURE: Factors that affects blood flow
Tutorials
Worksheets
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ActivitiesReading/Note-taking/ Assessment Questions: Chapter 33 Textbook Pages 948-961
Diagram: The Heart and trace the flow of oxygenated and deoxygenated blood through the heart, lungs, and body
Lab Bench: Circulatory Physiology
Video Game: Case of the Ailing Heart
Edgenuity: SC. 912.L.14.36 The Cardiovascular System
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Practice Questions here
EOC Practice Questions
Types of Blood Vessels
How does blood flow through the heart?
Blue=carbon dioxide rich blood
Red= oxygenated blood
Then the cycle repeats. Blood circulates through out your body following two pathways or circuits:
Red= oxygenated blood
- From the body tissues to the;
- Right Atrium
- Right Ventricle
- Pulmonary Artery
- Lungs (gas exchange)
- Pulmonary Vein
- Left Atrium
- Left Ventricle
- Aorta Artery(Out into the body tissues)
Then the cycle repeats. Blood circulates through out your body following two pathways or circuits:
- the systemic circuit:
- the pulmonary circuit:
What Factors Affect Blood Flow?
Blood pressure
Blood volume
Resistance
Disease
Stress
Exercise
Blood volume
Resistance
Disease
Stress
Exercise
Blood Pressure
Refers to the pressure of circulating blood on the walls of blood vessels,
- Blood pressure is affected by several factors including peripheral resistance, vessel elasticity, blood volume, and cardiac output
- Highest Pressure at left Ventricle--Squeezes blood to aorta and out to the body
- Lowest pressure is blood returning to heart at right Atrium
Blood Volume
- Reduced blood volume (for example due to excessive sweating, or excessive bleeding ) reduces blood pressure.
- Increased blood volume (for example due to water retention from excessive salt intake) increases blood pressure.
Vascular Resistance
Refers to the force that must be overcome to push blood through the circulatory system and create flow. (The force that slows down blood flow).
There are three (3) factors affect resistance:
There are three (3) factors affect resistance:
- Viscosity of the blood
- Diameter (radius) of the blood vessel
- Length of the blood vessels
Viscosity of the blood
Viscosity: Thickness of the blood. The greater the viscosity, the less easily molecules slide past one another and the more difficult it is to get the fluid moving and keep it moving. Ex. Viscosity increases in individuals with diabetes.
Diameter of the blood vessel
If Resistance increases, Blood flow decreases, and blood pressure increases
Example:
If the diameter of the blood vessel decreases (vasoconstriction), then resistance increases.
This happens during atherosclerosis
The opposite will happen if the diameter increases (vasodilation)
Example:
If the diameter of the blood vessel decreases (vasoconstriction), then resistance increases.
This happens during atherosclerosis
The opposite will happen if the diameter increases (vasodilation)
* Imagine yourself sipping a smoothie though a thin straw, then through a thicker straw. Which one will offer less resistance, and will allow more flow of the beverage?
- Narrow blood vessels offer more resistance= LESS FLOW = +++ blood pressure
- Thicker blood vessels offer less resistance= MORE FLOW = ---- blood pressure
ATHEROSCLEROSIS
A diet high in cholesterol causes a disease known as atherosclerosis.
- Blood vessels become less elastic, which can lead to high blood pressure.
- * If Resistance increases, Blood flow decreases, and blood pressure increases
Length of the blood vessel
- Longer vessels touch more blood than shorter vessels, therefore longer vessels offer more resistance to the path of the blood.
- Longer vessels have a decreased blood flow.
- Shorter vessels have an increased blood flow.
Diseases
Diseases that affect blood flow in the human body include:
- Atherosclerosis: Condition in which arteries become narrower due to the deposit of fatty material (cholesterol), and flow of blood decreases, vessels become less elastic, and lead to high blood pressure. May lead to stroke (in brain) or heart attack.
- Hypertension: Blood pressure in arteries is elevated (140 / 90 or higher), caused by diet high in salts, sustained stress or by atherosclerosis: If arteries lose their elasticity and become more rigid, blood pressure increases. Hypertension causes small tears in blood vessels, setting the stage for atherosclerosis. Uncontrolled hypertension can lead to: Heart attack, Stroke, Kidney damage.
- Smoking causes fatal damage to multiple human body system.
Smoking causes vessels to constrict (narrow) which decreases blood flow through the body. - Diabetes: Medical conditions that slow down blood flow. In diabetes, there is an elevated level of sugar in the blood. This increase in glucose causes the blood to be viscous or thicker causing the flow to decrease.
- Sickle Cell Anemia: Genetic disease caused by a mutation that produces abnormal red blood cells in a “C” shape. This cells get stuck, block vessels and clump together. Individuals suffer from pain, tiredness, and require blood transfusions.
Exercise
During exercise your muscles require higher amounts of energy (ATP). The process of cellular respiration will break down glucose molecules to meet that demand, but it also requires oxygen. Therefore exercise will:
- increase the breathing rate to provide muscles with more oxygen,
- the heart will beat faster and harder to get more oxygen to cells
- this will increase blood pressure
- blood vessel will become more dilated (enlarged diameter)
- which will increases blood flow
- this will result in more blood to muscles, less to stomach, but the same blood to brain, thus more oxygen, so more ATP will be generated.
Vocabulary
- Blood pressure: Pressure exerted against the blood vessel walls by moving blood. ls highest as left ventricle squeezes, contracts, and is lowest at right atrium when deoxygenated blood comes from the body.
- Blood volume: Volume of blood (both red blood cells and plasma) in the circulatory system of any individual. A typical adult has a blood volume of approximately 5 liters, with females generally having less blood volume than males.
- Resistance: Force that slows down blood flow. Ex. The resistance offered by the constriction (narrowing) of peripheral vessels to the blood flow in the circulatory system.
- Viscosity: Thickness of the blood. The greater the viscosity, the less easily molecules slide past one another and the more difficult it is to get the fluid moving and keep it moving. Ex. Viscosity increases in individuals with diabetes.
- Vasoconstriction: The narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles.
- Vasodilation: refers to the widening of blood vessels.