Cardiovascular System

Chapter 42

IB Biology

Biological Function of Cardiovascular System

• T R A N S P O R T !– Maintains constant flow of :

• Nutrients

• Hormones

• Respiratory Gases

• Wastes

• Enzymes

to /from tissue cells!

3 Major Componentsof CV System

1. Blood

2. Blood Vessels1. Arteries / Arterioles

2. Veins / Venules

3. Capillaries

3. Heart

Heart Anatomy

250-300 grams--size of fist

Located in mediastinum

Rests on diaphragm2/3 left of midlineShifts toward right shoulderApex points to left hip

Protective Features of the HeartP E R I C A R D I U M

• Layered membrane surrounding heart

• Fibrous pericardium– Tough, superficial layer

• Serous pericardium– Thin, deep layer subdivided into:

• Parietal layer: lines underside of fibrous pericardium

• Epicardium: lines external surface of heart

• Pericardial cavity: btwn parietal layer and epicardium

filled with fluid!

Pericarditis

• Inflammation of pericardium

• Pericardial fluid increases pressure on heart

• Cardiac tamponade

Heart Anatomy

3 Layers of Heart Wall

1. Epicardium: Superficial Layer

Composed of CT

2. Myocardium: Intermediate Layer

Composed of Muscle

3. Endocardium: Deep Layer

Composed of Endothelium

Internal Heart Anatomy

FOUR CHAMBERS

2 ATRIA(Right Atrium, Left Atrium)

Entry Chambers

2 VENTRICLES(Right Ventricle, Left Ventricle)

Exit Chambers

Right atrium

Left atrium

Right ventricle

Left ventricle

So what’s the big deal about a four chambered heart?

E F F I C I E N C Y

What leads to the heart’s efficiency?

A T R I O V E N T R I C U L A R

S E P T U M

wall that creates a physical separation between right and left sides of heart

(Interatrial septum + Interventricular septum = Atrioventricular Septum)

A V

SEPTUM

How does the AV septum lead to efficiency?

Creates two hearts in one!

Maintains separation between oxygenated blood (high O2 / low CO2 ) and deoxygenated blood (low O2 / high CO2 )

Oxygenated blood always on left side!

Deoxygenated blood always on right side!

Mixing of Blood Occurs!

Mixing of Blood Prevented!

FOUR MAJOR BLOOD VESSELS ATTACHED TO HEART

1. VENA CAVA major vein of body

2. AORTAmajor artery of body

3. PULMONARY ARTERY

4. PULMONARY VEIN

superior vena cava

inferior vena cava

pulmonary artery

aorta

pulmonary veins

pulmonary veins

Coronary Artery

• Provides blood to the myocardium of the heart!

Arteries vs. Veins

ARTERY

Always conducts blood AWAY from the heart!

Usually carries oxygenated blood

VEIN

Always conducts blood TOWARD the heart!

Usually carries deoxygenated blood

Heart Valves

• Flaps that open/close passageways for blood through the heart

2 Major Types of Valves:

1. Atrioventricular (AV) ValvesFound between atria and ventricles

Right AV Valve = Tricuspid Valve

Left AV Valve = Bicuspid Valve / Mitral Valve

Chordae tendinae / papillary muscles

• Open/close AV valves

• Prevent valves from opening backwards

Valves prevent backflow

incompetent valve

heart murmur

2. Semilunar Valves

found between ventricles and blood vessels leading out of the heart

Right Valve = Pulmonary Semilunar Valve

Left Valve = Aortic Semilunar Valve

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Right AV (tricuspid)

Left AV (bicuspid)

Pulmonary semilunar

Aortic semilunar

Circulatory Pathways

Systemic Circulation:

blood flows to/from body tissues

Pulmonary Circulation:

blood flows to/from lungs

Coronary Circulation:

blood flows to/from heart muscle

The Heart’s Assignment…

…maintaining blood flow through ALL circulatory pathways of the body!

Right side receives blood from tissues and

pumps to lungs(pulmonary circulation)

Left side receives blood from lungs and

pumps to tissues(systemic circulation)

Pathway of Blood Through the Heart

Heart acts as double pump (Rt side/left side)

Both pumps act in unison

Deoxygenated blood returns to heart through vena cava

Right side pumps blood to lungs

Oxygenated blood returns to heart through pulmonary veins

Left side pumps blood to body

Blood through

the heart

Capillaries of lungs for oxygenation

Inferior & superior vena cavae

Right atriumTricuspid valve

Right ventricle

Pulmonary semi- lunar valve

Pulmonary trunk (arteries)

Arteries of body

Capillaries of tissues--exchange gasesVeins of body

Pulmonary veins

Left atrium

Bicuspid valve

Left ventricle

Aortic semi- lunar valveAorta