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?