Cardiovascular System
APL2/L3
Cardiovascular System
Consists of:-a muscular pump, heart-a system of distribution vessels,
arteries, veins and capillaries
-a circulating fluid, blood
Cardiovascular System Functions include:
– transport of oxygen and carbon dioxide
– delivery of food to cellsremoval of waste products from cells
– distribution of hormonesassists in maintenance of homeostasis
e.g. temperature regulation
Workings of the heart
How much blood is in our body? 5-6 liters
What is average resting HR? 65-75 bpm
How much blood is pumped throughout the body every day?
7000 liters
Throughout one’s lifetime, heart can circulates 2.5 billion liters of blood
Blood VesselsArteries carry blood away from the heart
relatively thick walls to withstand higher blood pressure
smooth muscles modify diameter and thus regulate blood flow
Blood VesselsVeins carry blood towards the heart
thinner walls than arteries, not subject to high pressure
contain one-way valves that regulate direction of blood flow
Blood VesselsCapillaries connect arteries to veins
site of exchange between blood and surrounding tissues
walls one cell thick
extremely numerous, deliver blood close to all body cells
Coverings of the Heart Double layered
Pericardium– Visceral: inner,
delicate lining on surface of heart
– Parietal: outer, tough sac fitting loosely around heart
Pericardial cavity: space between 2 layers.
Filled with fluid to ↓ friction
Wall of heart: 3 Layers
Epicardium: protective outer membrane
Myocardium: middle, heart wall, rich in blood – Cardiac muscle
Endocardium: inner lining of heart wall– Purkinje fibers,
collagen, elastin, BV’s
Human Heart
4 chambers: 2 atria and 2 ventricles
Atria receive blood from various parts of the body, and pump blood into the ventricles
Ventricles pump blood out to various parts of the body
LUNGS
BODY
Double Loop System
Heart chambers: Four
2 Atria: Thin walled upper chambers– Receive blood
2 ventricles: Thick walled lower chambers– Pump blood out
R. & L. sides separated by septum
Valves between Artia and Ventricles
One set separates the atria & ventricles
Tricuspid: (3 cusps)– Separates
Right atria and R. ventricle
Bicuspid: (2 cusps)– Seperates left
atria & L. ventricle
Valves between ventricles and blood vessels out of heart
Another set separates the exiting blood vessels and the ventricles
Pulmonary valve: Right ventricle & pulm. Artery
Aortic valve: Left ventricle & aorta
Right Semilunar Valve
Left Semilunar Valve
Tricuspid Valve
Bicuspid Valve
Blood Flow on Right Side of Heart
Right Atrium
Right Ventricle
Left Atrium
Left Ventricle
Blood Flow on Left Side of Heart
Pulmonary Artery
Aorta
Vena Cava (2 veins)
Pulmonary Veins (4 veins)
Pulmonary Artery – O2 poor blood to lungs
Aorta – O2 rich blood to body
Vena Cava – O2 poor blood from body
Pulmonary Veins – O2 rich blood from lungs
Path of Blood Flow in Heart
Quick Quiz: 10 points
1. What type of blood vessels:a. Carry blood low in oxygen back to the heart?b. Have higher BP and thick walls, high in oxygen?c. Are one cell thick ?
2. Why is the blood flow related to the heart considered a double-loop system?
3. a. What valve is between the left atria
and left ventricle? b. What is another name for it?
4. What one of the four heart chambers have the thickest walls?
Why?
5. Blood from the body is received into the RA via what two large veins?
