circulatory system

The Circulatory System:

The Circulatory System 9 th Grade Biology Alaine Davis Woodinville Montessori School

Purpose of the Circulatory System:

Purpose of the Circulatory System To move materials from one part of the body to another Nutrients and oxygen must be delivered to every single cell in the body Carbon dioxide and other cellular waste products need to be removed from cells and, eventually, eliminated from the body The circulatory system interacts closely with the respiratory system. Together they are often referred to as the cardiorespiratory system

Main Parts of the Circulatory System:

Main Parts of the Circulatory System Heart Arteries Veins Capillaries Blood

Fun facts about The Heart:

Fun facts about The Heart The heart is essentially a strong muscular pump approximately the size of two fists It weights a little more than half a pound It is located in the center of the chest, tilted slightly to the left If you are 14 ½ years old, your heart has already pumped 550 millio n times More heart attacks occur on Monday than any other day of the week

Characteristics of Arteries:

Characteristics of Arteries Arteries are defined as blood vessels that carry blood away from the heart They usually carry oxygenated blood, but there is one exception (which will be discussed later) Arteries are thick and muscular , with many layers in their walls; this helps them maintain your blood pressure as the blood is pumped throughout the body They run along the bone , located deep (why?) Smaller arteries (as they branch apart) are called arterioles When they get even smaller than that, they are capillaries

arteries:

arteries

Capillaries:

Capillaries Capillaries are the tiniest blood vessels They are the actual location of gas exchange (O2 entering cells, CO2 leaving cells) They are so narrow that only one red blood cell at a time can fit through Every single cell in your body must have contact with a capillary

capillaries:

capillaries

Characteristics of Veins:

Characteristics of Veins Veins are defined as blood vessels that carry blood toward the heart They usually carry deoxygenated blood, but there is one exception (which will be discussed later) They run near the surface (superficial)

Characteristics of Veins:

Characteristics of Veins Veins are thin and flabby and have valves (why?) Smaller veins are called venules The thinnest veins are considered capillaries

Anatomy of the Heart:

Anatomy of the Heart Mammalian hearts have four chambers Right atrium Right ventricle Left atrium Left ventricle Pacemaker : an area of the right atrium that sends electrical signals telling the heart to contract

Anatomy of the Heart:

Anatomy of the Heart

Blood flow through the Heart:

Blood flow through the Heart The pulmonary circuit : from heart to lungs and back again The systemic circuit : from heart to all parts of the body and back again

Blood:

Blood The only liquid connective tissue in the body (what are other connective tissues?) An adult has about a gallon and a half of blood Composed of: 55% plasma (which is mostly water, with dissolved salts and minerals in it) Red Blood Cells ( RBCs , aka erythrocytes) White Blood Cells ( WBCs , aka leukocytes) Platelets

RBCs:

RBC s RBC = red blood cell They have no nucleus There are approximately 25 trillion in your body RBCs are made in the bone marrow at a rate of 2 million per second

RBCs:

RBC s Each RBC has 250 million hemoglobin molecules Each hemoglobin molecule can carry 4 molecules of O 2 Hemoglobin is a good transporter of oxygen because it contains iron , which binds O 2

RBCs:

RBC s Which genetic disorder have we studied which affects the shape of red blood cells? (hint on next slide)

RBCs:

RBC s Which genetic disorder have we studied which affects the shape of red blood cells?

WBCs:

W BC s WBC = white blood cell a.k.a. leukocytes Part of the immune system Fight infections and cancer The number of WBCs in the blood increases when you are fighting an infection HIV attacks a specific type of WBC called a T-cell

Platelets:

Platelets Look like small fragments of blood cells Play important role in clotting of blood with a complex cascade of chemical reactions that makes blood cells and platelets stick together We have studied a genetic disease that impairs a person’s ability to clot blood—what was it?

Cardiovascular Health:

Cardiovascular Health Plaque – a deposit of cholesterol, calcium and fat inside a blood vessel. It builds up over time based on a person’s diet and exercise. Arteriosclerosis – narrowing of the arteries as a result of plaque building up. Atherosclerosis – hardening of the arteries; an advanced stage of plaque buildup.

arteriosclerosis:

arteriosclerosis

Cardiovascular Health:

Cardiovascular Health Hypertension – high blood pressure (140/90 or above); it damages the heart and blood vessels. Stroke – blockage of an artery leading to the brain; leads to damage of brain tissue, paralysis, loss of speech, or death Heart attack – blockage of an artery leading to the heart itself; if the heart cannot get oxygen for itself, it cannot function

Actions for cardiovascular health:

Actions for cardiovascular health Don’t smoke Exercise regularly Limit intake of fat and cholesterol Limit intake of salt Maintain a healthy weight Get blood pressure checked regularly