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The Circulatory SystemThe Circulatory System

Human Biology 11Ms. Bowie

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Learning Outcomes Describe the structure of the heart and the function of each part. Trace the flow of blood through the heart. List the most common heart sounds and what events produce

them.

List the different types of blood vessels and describe the functions of each.

Trace the flow of blood through the pulmonary and systemic circulation.

List the different types of blood vessels and describe the functions of each.

Trace the flow of blood through the pulmonary and systemic circulation.

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Learning Outcomes (cont.)

List and describe the components of blood.

Give the functions of red blood cells, the white blood cells, and platelets.

List the substances normally found in plasma.

Explain how bleeding is controlled.

Explain the differences among blood types A, B, AB, and O.

Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system.

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HEART STRUCTURES

Part 1

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Introduction The circulatory system consists of heart (a pump)

and blood vessels (tubes)

Blood is sent to: Lungs for oxygen Digestive system for nutrients Every cell of the body to deliver “products”

It also circulates waste products to certain organ systems for removal from the blood

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The Heart: Structures

The heart is an organ about the size of a loose fist

Located slightly left of the midline

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The Heart: Structures (cont.)

The Heart has 4 chambers Two atria

Upper chambers Left and right Separated by a septum

Two ventricles Lower chambers Left and right Separated by a septum

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The Heart Valves: Structures (cont.)

Tricuspid valve – prevents blood from flowing back into the right atrium when the right ventricle contracts

Mitral valve – prevents blood from flowing back into the left atrium when the left ventricle contracts

Pulmonary valve – prevents blood from flowing back into the right ventricle

Aortic valve – prevents blood from flowing back into the left ventricle

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PULMONARY SYSTEM OF CIRCULATION

Part 2

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The Heart: Blood Flow

Deoxygenated blood in from

bodyOxygenated

blood in lungs

Atria Contract Ventricles Contract

Deoxygenated blood out to lungs

Oxygenated blood out to

body

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The Heart: Blood Flow (cont.)

The pulmonary system explains the flow of blood through the heart & lungs. It does not include the rest of the body.

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SYSTEMIC CIRCULATION OF THE BLOOD

Part 3

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Blood Vessels: Arteries and Arterioles Carry blood away

from the heart

Strongest of the blood vessels

Under high pressure

Arterioles Small branches of arteries

Aorta Takes blood from the

heart to the body Gives an extra “push”

Coronary arteries Supply blood to heart

muscle

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Blood Vessels: Veins and Venules Blood under no pressure in

veins

Moves blood BACK to the heart

Low pressure means that the blood needs help to get back to the heart

Muscle contractions in the body help move blood

Valves in the veins prevent backflow

Venules

Small vessels formed when capillaries merge

Superior and inferior vena cava

Largest veins

Carry blood into right atrium

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Blood Vessels: Capillaries

Tiniest branches of arterioles

Smallest type of blood vessel

Connect arterioles to venules

Only about one cell layer thick

Oxygen and nutrients can pass out of a capillary into a body cell

Carbon dioxide and other waste products pass out of a body cell into a capillary

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The Heart: Cardiac Cycle The systemic circulation describes the flow of blood through

the vessels that supply the body. It does not include the lungs.

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HEART BEATCARDIAC RHYTHM

Part 4

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The Heart: Heart Sounds

One cardiac cycle – two heart sounds (lubb and dubb) when valves in the heart snap shut Lubb – First sound

When the ventricles contract, the tricuspid and mitral valves snap shut

Dubb – Second sound When the atria contract and the pulmonary and aortic

valves snap shut

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COMPOSITION OF THE BLOOD

Part 5

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Blood Composition

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Blood A tissue made up of:

Red blood cells (erythrocytes)

White blood cells (leukocytes)

Platelets – cell fragments

Plasma – fluid part of blood

Average-sized adult has 4 to 6 liters of blood

Amount depends on: Size of person Amount of fat tissue Gender - females have

less than males

Average-sized adult has 4 to 6 liters of blood

Amount depends on: Size of person Amount of fat tissue Gender - females have

less than males

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Blood Components: Red Blood Cells Erythrocytes

Another name for red blood cells

Transports oxygen throughout the body Hemoglobin is a pigment in RBCs

Oxyhemoglobin carries oxygen; bright red Deoxyhemoglobin does not carry oxygen; darker red

Carries carbon dioxide Blood is NEVER actually blue! Anemia

Is a condition where a person has a low red blood cell count

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Blood Components: Platelets

Platelets form sticky nets that are important in the blood clotting process.

 

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Blood Components: Plasma

Liquid portion of blood composed mostly of water

Proteins Albumins

Pull water in to the blood help maintain blood pressure

Globulins – transport fats and vitamins

Fibrinogen – the “glue” that holds platelets together and are needed for blood clotting

Nutrients Amino acids Glucose Nucleotides Lipids from the digestive

tract

Gases – oxygen, carbon dioxide, and nitrogen

Electrolytes Waste products

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BLOOD TYPES

Part 6

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Blood Types

Types are distinguished by antigen (“think – gang colours”) and antibodies

There are 4 main types: Antigen A (Type A blood) Antigen B (Type B blood) Combination A + B (AB)

(Type AB blood) No Antigens at all

(called O Type)

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Blood Types (cont.)

Blood Type Antigen Present

(Gang colours)

Antibody Present(attackers)

People with this blood type can

receive:

A A B Types A and O

B B A Types B and O

AB AB None ALL Blood Types

A, B, AB, and O

O None A and B Only Type O

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HEART DISEASE SIGNS & SYMPTOMS

Part 7

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Diseases and Disorders of the Cardiovascular System

Disease Description

Anemia The blood does not have enough red blood cells or hemoglobin to carry an adequate amount of oxygen to the body’s cells

Aneurysm A ballooned, weakened arterial wall

Arrhythmias Abnormal heart rhythms

Carditis Inflammation of the heart

Endocarditis Inflammation of the innermost lining of the heart, including valves

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Disease Description

Myocarditis Inflammation of the muscular layer of the heart

Pericarditis Inflammation of the membranes that surround the heart (pericardium)

Congestive Heart Failure

Weakening of the heart over time; heart is unable to pump enough blood to meet body’s needs

Coronary Artery Disease (CAD)

Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within the arteries

Diseases and Disorders of the Cardiovascular System (cont.)

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Disease Description

Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg

Leukemia Bone marrow produces a large number of abnormal WBCs

Murmurs Abnormal heart sounds

Myocardial Infarction

Heart attack; damage to cardiac muscle due to a lack of blood supply

Diseases and Disorders of the Cardiovascular System (cont.)

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Disease Description

Sickle Cell Anemia

Abnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillaries

Thalassemia Inherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCs

Thrombophlebitis Blood clots and inflammation develops in a vein

Varicose Veins Twisted, dilated veins

Diseases and Disorders of the Cardiovascular System (cont.)

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Apply Your Knowledge

ANSWER: Anemia is a condition in which a person does not have enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to body cells.

The doctor has told your patient she has anemia. How would you explain this to the her?

Bravo!

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In Summary Circulatory system

Transport system for body Heart, arteries, veins, and capillaries

Blood Transport medium RBCs, WBCs, platelets, plasma