The Human Heart
The Human heart is designed as a pair of side-
Atria: These thin-walled, muscular chambers.
Ventricle: Each side also had a thick walled
The main transport system in humans consist of blood,
the heart to pump it and blood vessels through which it
Vesselss, arteries, and capilaries
Three Types of Blood Vessels:
and body tissue
away from the
back the heart.
absent present present
absent Thick layer Thin layer
Valves absent absent present
Inner Layer or
present present present
Humans have one way blood flow.
The Pulmonary circulation is to and from the
lungs, which means the blood that is coming from
lungs would have plenty of oxygen. Furthermore,
blood that is de-oxygenated will contain carbon
dioxide. Systemic circulation is to and from all
other organs, including the wall of the heart itself.
6.2.1 Draw and label a diagram of the heart showing the four
chambers, associated with blood vessels, valves and the
route of blood through the heart
6.2.2 State that the coronary arteries supply heart
muscle with oxygen and nutrients.
Coronary arteries: Coronary circulation is the
circulation of blood in the blood vessels of
the heart muscle (the myocardium). The vessels
that deliver oxygen-rich blood to the myocardium
are known as coronary arteries. The vessels that
remove the deoxygenated blood from the heart
muscle are known as coronary veins.
myogenic muscle contraction, the role of of the
pacemaker, nerves, the medulla of the brain and
The Medulla Oblongata: the medulla is in the charge of
automatic function; relays nerve signals between the brain and
spinal cord. Furthermore, this is responsible of cardiac,
respiratory, vomiting, and other functions. In relations to heart
beat and blood pressure, the medulla controls both functions.
Myogenic Muscle Contraction: How arteries and arterioles
react to an increase or decrease of blood pressure to keep the
Epinephrine: a hormone and neurotransmitter that enables to
increase heart rate, contracts blood vessels, dilates air
passsages, and participate sympathetic response.
Continued from the last slide:
Beats originate in a structure in the muscle of the
wall of the right atrium, called the pacemaker.
Special muscle fibers radiate out from the
pacemaker, conducting the impulse to the
muscles of both atria, triggering contraction there.
Ventricular contraction is triggered.
After every contraction, cardiace muscle has a
period of insensitivity to stimulation, when the
heart refills with blood.
Did you know that the heart’s natural rhythm set
by the pacemaker is about 50 beats per minute?
Continued from the Last Slide:
- The Medulla= the control contre.
- When the medulla in our brain sends signals one
nerve, it triggers the speeding up of the heart rate,
and the other one slows down the speeding.
- This opposite effect is called, antagonistic.
- Furthermore, adrenaline causes the pacemaker
to increase the heart rate.
6.2.6 State that blood is composed of plasma, erthrocytes,
leucocytes (phagocytes and lymphoycytes)
Plasma Liquid portion of blood
Erthrocytes Red blood cells (carry oxygen and
Leucocytes White blood cells (phagocytes and
Platelets Cell fragments (assist in blood clotting)
1. Atrium muscle contract, pushing blood past the
bicuspid valve into the ventricle.
2. Atrium muscles relax.
3. Ventricle muscles contract, causing blood
pressure to close the bicuspid valve and open the
semilunar valves, forcing blood into the aorta.
4. Ventricle and atrium muscle relax, while the
pressure of blood in the aorta causes the
semilunar valves to shut.
5. Blood flows into the atrium and opening the
biscupid valve as it starts to flow into ventricle.
The purpose: it prevents blood from flowing
backward; therefore, maintaining the direction of
flow through the heart.
Atrio-ventricular valves: large valves, positioned
to prevent backflow from ventricles to atria.
Atrio-ventricular valve that is on the right side is
tricuspid valve, and on the left is the bicuspid.
Semilunar valves: a different type of valve
separates the ventricles from pulmonary artery
(right side) and aorta (left side)
6.2.7 State that the following are transported by the
blood: nutrients, oxygen, carbon dioxide, hormones,
antibodies, urea, and heat.
What is transported What it is or does
Nutrient Glucose, amino acids, etc.
Oxygen Reactant needed for aerobic cell
Carbon dioxide Waste product of aerobic cell
Hormones Transported from glad to target cells
Antibodies Protein molecules invovled in
Urea Nitrogenous waste (filitered out of
the blood by kidneys)
Heat Skin arterioles (can change
diameter in order to gain or lose