Cardiovascular System

Aka: The Circulatory System

Structure

• Heart

• Blood Vessels

• Blood

What does it do?

• Moves the blood• Protects the body• Transports nutrients• Removes metabolic

waste• Regulates body

temperature

Heart Structure Function

Atrium Upper Chamber- receives the blood

Ventricle Lower chamber – pumps blood out

Aorta Brings oxygen rich blood from left ventricle to the body

Vena Cava Brings oxygen poor blood to the atrium

Pulmonary Vein Brings oxygen rich blood from the lungs to the left atrium

Pulmonary Artery Brings oxygen poor blood to the lungs

Valves Prevent blood from flowing back

Your Diagram

• 1. Aorta• 2. Vena Cava• 3. Right Pulmonary Artery• 4. Pulmonary Veins• 5. Right atrium• 6. Tricuspid Valve• 7. Right Ventricle• 8. Lower / Inferior Vena Cava

Your Diagram

9. Left Pulmonary Artery

10. Left Pulmonary Veins

11. Left Atrium

12. Mitral or Bicuspid Valve

13. Aortic Valve

14. Left Ventricle

15. Septum

Four Steps of Circulation

• Step 1: From right side of heart to lungs to collect O2 turning blood bright red and CO2 leaves the capillaries through diffusion.

• Step 2: Oxygenated blood returns to the left side of the heart. (Pulmonary Circulation)

• Step 3: Blood is pumped to all parts of the body distributing O2 and nutrients

• Step 4: Blood returns to the right side of the heart a reddish-blue color to be oxygenated again (Systemic Circulation)

What allows the heart to keep its beat?

• The sinoatrial node abbreviated SA node is the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm.

• It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava.

What allows the heart to keep its beat?

• http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000001&ptid=57

• http://kidshealth.org/parent/medical/body_basics/heart.html

What allows the heart to keep its beat?

• The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle of His, bundle branches, and Purkinje fibers. The SA node (anatomical pacemaker) starts the sequence by causing the atrial muscles to contract. From there, the signal travels to the AV node, through the bundle of His, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract. This signal creates an electrical current that can be seen on a graph called an electrocardiogram (EKG or ECG). Doctors use an EKG to monitor the cardiac conduction system’s electrical activity in the heart.

2 Phases of a Heart Beat

• In the diastole phase, the heart ventricles are relaxed and the heart fills with blood.

• In the systole phase, the ventricles contract and pump blood to the arteries.

• One cardiac cycle is completed when the heart fills with blood and the blood is pumped out of the heart.

Blood Pressure

• The force of blood pushing against artery walls

• Strongest when heart contracts (systolic or the higher number)

• Weakest when heart relaxes (diastolic or the low number)

• 120/80 is considered normal BP

Pulse

• Rhythmic contractions of arteries can be felt through the skin.

• Keeps pace with heart beat.

• A way to measure vital health statistics

Types of Vessels

Arteries Veins Capillaries

Cross Sectional View

Function transports blood away from the heart

transports blood from various regions of the body to the heart

exchange materials with their surroundings

Structure of the Blood

Plasma Red Blood Cells

White Blood Cells Platelets

Diagram

Key Parts

water (90%) proteins, glucose, clotting factors, minerals hormones and carbon dioxide

No nucleus cytoplasm contains hemoglobin which binds to oxygen

derived from hematopoietic stem cells. Complex nucleus, lysosomes, histimine

No nucleus, fragment of a megakaryocyte

Function Transportation medium

Deliver Oxygen

defend the body against disease and foreign materials

Blood clotting

Where is it made?

H2O portion is absorbed by capillaries, blood cell in bone marrow

Bone Marrow Bone Marrow Bone Marrow

Blood is made of…

• Erythrocytes (RBC)

• Leukocytes (WBC)

• Platelets

• Plasma

Differentiated Blood Cells

Erythrocytes

• Red Blood Cells (RBC)• Transport Oxygen and

Carbon Dioxide• Flattened Doughnuts

with depressed center for increased surface

• Flexible to get through vessels

• No nucleus – last 120 days broken down in spleen

Leukocytes

• White Blood Cells (WBC)

• Protects body from foreign microbes and toxins

• Found in blood stream and some tissue

• Last 18-36 days• Three types

Types of Leukocytes• Lymphocytes: Immune function• Granulocytes: Destroy bacteria, viruses, parasites• Macrophages: Break down old blood cells and foreign

matter like dust and asbestos

Platelets

• Aka: Thrombocytes• Clot blood• Release coagulating

chemicals• No nucleus• Fragments of

Megakaryocytes• Stimulate Immune

System and Fight Infections

Plasma

• Clear liquid protein and salt part of the blood

• 55% of our blood volume

• 95% of plasma is H2O

• Contains: nutrients, clotting factor, hormones, antibodies, vitamins, lipids, sugars, other proteins, metabolic waste

Blood Formation - Hematopoiesis

• Bone Marrow produces red blood cells, most white blood cells and platelets

• All blood cells originate from stem cells

• Production is based on body need such as infection or bleeding

How blood circulates….

• Closed system of blood vessels

• Four chambers of the heart

• http://www.youtube.com/watch?v=xagOnC6sZEU

The Heart - Structure

• Four cavities that fill with blood

• Two are Atria (Upper “Round” Half)

• Two are Ventricles (Lower “pointed” Half)

• Points to left side of chest at the bottom

• Size of fist• Pumps 4300 gallons /

day

Heart - Function

• Connects to Aorta at the top. Main artery carrying blood away

• Pulmonary Artery connects heart to lungs

• Two largest veins = Carry blood into heart are superior vena cava and inferior vena cava.

Heart - Function

• Cardiac Muscle• Contracts 70-80 times

per minute• Nerves connected to

the heart regulate speed of muscle contraction

Blood Vessels - Structure• Three Types:

1. Arteries - thick and flexible due to forceful bloodflow

2. Veins- appear blue, thinner walls than arteries, less forceful flow

3. Capillaries – tiniest vessels, connect arteries and veins. Very thin walls

Blood Vessel - Function

• Arteries: Carry oxygenated blood from heart to tissues. Arteries to Arterioles to capillaries

• Veins: Carry deoxygenated blood to heart. Capillaries – Venuoles – Veins

• Capillaries: gas exchange and absorb metabolic waste