Download Cardiovascular System

Cardiovascular System
Chapter 42
IB Biology
Biological Function of
Cardiovascular System
• TRANSPORT!
– Maintains constant flow of :
•
•
•
•
•
Nutrients
Hormones
Respiratory Gases
Wastes
Enzymes
to /from tissue cells!
3 Major Components
of CV System
1. Blood
2. Blood Vessels
1. Arteries / Arterioles
2. Veins / Venules
3. Capillaries
3. Heart
Heart Anatomy
250-300 grams--size of fist
Located in mediastinum
Rests on diaphragm
2/3 left of midline
Shifts toward right shoulder
Apex points to left hip
Protective Features of the Heart
PERICARDIUM
• 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
Right
ventricle
Left
atrium
Left
ventricle
So what’s the big deal about a
four chambered heart?
EFFICIENCY
What leads to the heart’s efficiency?
ATRIOVENTRICULAR
SEPTUM
wall that creates a physical separation
between right and left sides of heart
(Interatrial septum + Interventricular septum
= Atrioventricular Septum)
AV
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. AORTA
major artery of body
3. PULMONARY ARTERY
4. PULMONARY VEIN
superior
vena cava
pulmonary
veins
inferior
vena cava
pulmonary
artery
aorta
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) Valves
Found 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
Right AV
(tricuspid)
Pulmonary
semilunar
Left AV
(bicuspid)
Aortic
semilunar
31
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
Inferior & superior
vena cavae
Right atrium
Tricuspid valve
Right ventricle
Pulmonary semilunar valve
Pulmonary trunk (arteries)
Capillaries of lungs for oxygenation
Pulmonary veins
Left atrium
Bicuspid valve
Left ventricle
Aortic semilunar valve
Aorta
Arteries of body
Capillaries of tissues--exchange gases
Veins of body