The Human Heart
& Associated Blood Vessels
Life Sciences Term 3
Grade 10
Thursday Lesson 6
19/08/2021
• Why do humans need a circulatory system?
• What purpose does blood serve
in the human body?
• What is the purpose of the heart?
• Where is the heart situated?
• What is the difference between
an artery and a vein?
• What happens if the heart stops beating?
• Is it possible to live without a heartbeat?
Complete labelled diagram of a Heart
Right
hand
side
Left
hand
side
Blood Circuits:
• Coronary blood circuit:
Provides blood supply exclusively to the heart muscle
• Systemic Circuit:
The blood supply to the entire body except the Heart and
lungs
• Pulmonary Circuit:
The blood circuit responsible for gaseous exchange of the
blood via the lungs
Cardiac
Cycle:
Grade 10: Thursday
Cardiac Cycle with corresponding
ECG:
0.2s
0.1s
0.3s
0.2s
0.8s
Nerve system controlling the
cardiac cycle
1. Atrial Systole:
Sino-atrial (SA) node triggers contraction
of atria (left and right).
2. Ventricular Systole/Atrial Diastole:
Signal Travels around atria and a signal is
sent to the Atrioventricular (AV) Node
shortly after, closing the Bicuspid and
Tricuspid valves and as the signal moves
down through the heart it triggers
contraction of the Ventricles via the
Purkinje Fibres which wrap around the
heart muscles.
3. General Diastole:
The atria continue to pull in blood while
the cuspid valves reopen and allow some
blood to fill the relaxing ventricles.
Purkinje
Fibres
Blood Vessels
Gaseous Exchange in tissues
Gaseous Exchange in Pulmonary
Circuit
Biotechnology
for
Heart
failure: