Download The Circulatory System

Starter Questions
• What is the difference between circulatory
systems between unicellular and multicellular
organisms.
• How many chambers does the heart have and
identify if they have oxygenated or
deoxygenated blood.
• How is an impulse transmitted across the heart?
The Circulatory
System Introduction
Chapter 37.1
Circulatory System
• Single cells can get nutrients from their
environment and get rid of wastes by
simple diffusion
• A circulatory system is only needed in
larger organisms with multiple cells
Body cells must be bathed in fluid to
transport nutrients and wastes
Types of Circulatory Systems
• Open Circulatory System
– No vessels
Blood just floats in the body cavities
• Closed Circulatory System
– Blood flows in a system of vessels
Human Circulatory System
The human
circulatory system
consists of the:
1. heart
2. a series of blood
vessels
3. blood
The Heart
Structure
• Composed of cardiac muscle
• Located near the center of your chest
• Pericardium: protective sac that encloses the heart
• Myocardium
– thick middle muscle layer of the heart
– Pumps blood through the c.s.
• Septum
– divides the left and right side of the heart
– prevents the mixing of oxygen-poor and oxygen-rich
blood
The Heart
Circulation through the body
• Two separate pumps
– Pulmonary Circulation
• the right side of the heart pumps blood from the heart
to the lungs and back again
• leaves deoxygenated, returns oxygenated
– Systemic Circulation
• the left side of the heart pumps blood from the heart
to the body and back again
• leaves oxygenated, returns deoxygenated
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The Heart
• Both pumps have an
atrium and a ventricle
– Atrium – upper
chamber (receives
blood)
– Ventricle – lower
chamber (pumps
out blood)
Pulmonary Circulation
• Right side of heart (right atria, right
ventricle)
– Pumps to and from lungs
oxygen poor blood to lungs
oxygen rich blood to heart
– Includes tricuspid valve, pulmonary valve,
pulmonary artery, pulmonary vein
Systemic Circulation
• Left side of heart (left atria, left ventricle)
– Pumps blood to and from body
oxygen rich blood leaves the heart
oxygen poor blood comes from the body
– Includes bicuspid valve, aortic valve, aorta,
and vena cava
Aorta
Superior Vena Cava
Brings oxygen-rich blood from the left ventricle
to the rest of the body
Large vein that brings oxygen-poor blood
from the upper part of the body to the
right atrium
Pulmonary Arteries
Pulmonary Veins
Bring oxygen-poor blood to the lungs
Bring oxygen-rich blood from each of the
lungs to the left atrium
Left Atrium
Pulmonary Valve
Aortic Valve
Prevents blood from flowing back into
the right ventricle after it has entered
the pulmonary artery
Prevents blood from flowing back
into the left ventricle after it has
entered the aorta
Right Atrium
Mitral Valve
Tricuspid Valve
Prevents blood from flowing
back into the left atrium after it
has entered the left ventricle
Prevents blood from flowing
back into the right atrium after
it has entered the right ventricle
Left Ventricle
Inferior Vena Cava
Vein that brings oxygen-poor blood from
the lower part of the body to the right
atrium
Septum
Right Ventricle
Blood Flow
• Goes from atria to ventricles to blood vessels
Valves
• flaps of connective tissue that prevent the back flow of
blood
• guarantees one-way flow
• increase pumping efficiency of the heart
4 valves in the heart
• Tricuspid valve– found in between the right atrium and right
ventricle
• Pulmonary valve - found in between the right ventricle and
pulmonary artery
• Mitral (bicuspid) valve - found in between the left atrium
and left ventricle
• Aortic valve - found in between the left ventricle and the aorta
Heart Control
• The heartbeat is actually two-different
muscular contractions
– 1st – contraction of the atria – SA node
started at the pacemaker in the right atria
– 2nd – contraction of the ventricles – AV node
The Heartbeat
The EKG
• Measures the electricity passing through
the heart at any specific time
• Can be used to diagnose heart conditions
• Each part of the EKG shows what is
happening in the heart
EKG Parts
• P Wave contraction of the atria
• QRS Complex contraction of the
ventricles
• T Wave resetting of the heart
The EKG
Blood Pressure
force that blood exerts on the arteries when the
heart contracts
• Measures using a device called a
sphygmomanometer
• Listen for the flow of blood through arteries
– Top number is called systolic pressure pressure
exerted by contracting ventricles
– Bottom number is called diastolic pressure pressure
exerted by resting ventricles
• Normal is 120/80
Blood Pressure
• Regulated in two ways:
– When stressed, neurotransmitters relax
muscles around arteries
• Lowers blood pressure
• Controlled by autonomic nervous system
– Hormones control retention in the blood
• Remove water to lower blood pressure