how much do you know? 1. how many blood cells are destroyed in the human body in one second?...
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How much do you know?1. How many blood cells are destroyed
in the human body in one second?
a) 150,000
b) 15,000,000
c) 150,000,000
2. A man’s heartbeat is faster than a women’s. True or False?a) Trueb) False
How much do you know?
3. The adult's heart pumps about 15,140 litres of blood in what amount of time?
a) One day
b) One hour
c) One week
How much do you know?
• 4. How long (on average) does it take for blood to circulate around the WHOLE body?
a) 23 seconds
b) 23 minutes
c) 23 hours
How much do you know?7. Human blood on its own is in colour.
clear
Haemoglobin, a pigment in the red blood cells, is responsible for the red colouring of the blood.
8. The average adult body contains of blood
and an has about 1 litre.
5-6 litres
infant
The Circulatory System
The Circulatory System• The function of a circulatory system is to carry blood
or hemolymph into close contact with every cell in the body.
• The most sophisticated circulatory systems consist of:– one or more pumps called hearts– arteries (tough, thick-walled tubes) that carry
blood away from the heart under high pressure;– small vessels called capillaries whose walls are
just one cell thick, allows the exchange of gases and other molecules with tissues in networks called capillary beds; and
– vessels called veins that return blood to the heart under low pressure
Functions of the Circulatory System
• Transport oxygen to cells• Transport nutrients from the
digestive system to body cells• Transport hormones to body cells• Transport waste from body cells to
excretory organs• Distribute body heat
•Blood : connective tissue that consists of cells in a watery extracellular matrix called plasma •Remainder of the blood is made up of formed elements: platelets, red blood cells, and several types of white blood cells:•Platelets : Cell fragments that minimize blood loss from ruptured blood vessels by releasing material that assists in the formation of clots •White blood cells: which are part of the immune system fight infections
How Are Oxygen and Carbon Dioxide Transported in Blood?
RBCs
• Red blood cells (RBCs):– transport oxygen from the lungs to
tissues throughout the body– critical role in transporting carbon
dioxide from tissues to lungs • In humans, red blood cells make up
99.9% of the formed elements. – contain an oxygen-carrying molecule
called hemoglobin
CirculationPulmonary Circuit
Systemic Circuit
How Does the Heart Work?
• In animals with closed circulatory systems, the heart contains at least two chambers.
• the atrium receives blood returning from
circulation• the ventricle generates force to propel the
blood through the system.
• Atria are separated from ventricles by atrioventricular valves.
• The number of distinct heart chambers has increased as vertebrates diversified.
How Does the Heart Work?
• Vertebrates evolved two separate pumping circuits: – The pulmonary circulation is a lower-
pressure circuit to the lungs. – The systemic circulation is a higher-
pressure circuit to the rest of the body.
lungs
head & arms
liver
digestive system
kidneys
legs
pulmonary artery
aorta
pulmonary vein
main vein
Left Right
Our circulatory system is a double circulatory system.
This means it has two parts parts.
Lungs
Body cells
the right side of
the system
deals with
deoxygenated
blood.
the left side of
the system
deals with
oxygenated
blood.
Components of the Human Circulatory System
The Heart
Blood Vessels
Blood
Lymphatic Vessels
Lymph
The Heart
These are arteries. They carry blood away from the heart.
This is a vein. It brings blood from the body, except the lungs.
Coronary arteries, the hearts own blood supply
The heart has four chambers
2 atria
2 ventricles
now lets look inside the heart
The Path of Blood
1. The heart pumps blood to the lungs
2. The blood gets oxygen in the lungs
3. The blood returns to the heart
4. The heart pumps the oxygenated blood to the cells in the body
5. The blood delivers oxygen to the body cells
6. The deoxygenated blood travels back to the heart
The Heart
Left Ventricle
Left AtriumRight Atrium
Right Ventricle
valve
Vein from Lungs
Artery to Head and BodyArtery to Lungs
Vein from Head and Body
valve
How does the Heart work?
STEP ONE
blood from the body
blood from the lungs
The heart beat begins when the heart muscles relax and blood flows into the atria.
How does the Heart work?
STEP TWO
The atria then contract and
the valves open to allow blood
into the ventricles.
How does the Heart work?
STEP THREE
The valves close to stop blood
flowing backwards.
The ventricles contract forcing
the blood to leave the heart.
At the same time, the atria are
relaxing and once again filling with blood.
The cycle then repeats itself.
Structure of the heart
You need to be able to label all parts of the heart
LEFT SIDERIGHT SIDE
Left ventricle – has a thicker muscle wall than right side – why?
Right ventricle
valve
right atrium ?
Blood from lungsBlood from ?
Body organs
LEFT SIDERIGHT SIDE
Left ventricleRight ventricle
valve
right atrium Left atrium
Blood from lungsBlood from ?
Blood to the ?Blood to the ?
Beating heart – blood flow
The valves prevent the backflow of blood.
How do the valves work?
How many can you see?
Atrium and ventricle muscles force the blood through and out of the heart
out
in in
Can you see the 4 valves?
blood from the heart gets around
the body through blood vessels
There are 3 types of blood vessels
a. ARTERY
b. VEIN
c. CAPILLARY
The ARTERY
thick muscle
and elastic
fibres
Arteries carry blood away from the heart.
the elastic fibres allow
the artery to stretch
under pressure
the thick muscle
can contract to
push the blood
along.
The VEIN
Veins carry blood towards the heart.
thin muscle and elastic fibres
veins have valves which act to stop the blood from going in the wrong direction.
body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.
The CAPILLARYCapillaries link Arteries with Veins
the wall of a capillaryis only one cell thick
they exchange materials between the blood and other body cells.
The exchange of materials between the blood and the body can only occur through capillaries.
artery vein
capillaries
body cell
The CAPILLARYA collection of capillaries is known as a capillary bedcapillary bed.
what’s in
red blood cells white blood cells
platelets
plasma
carbon dioxide
digested food
waste (urea)
hormones
oxygen
The Blood
plasma
red blood cell white blood cell
platelets
Red Blood Cells
contain haemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it.
can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.
a biconcave disc that is round and flat without a nucleus
White Blood Cells
there are many different types and all contain a big nucleus.
the two main ones are the lymphocytes and the macrophages.
some lymphocytes fight disease by making antibodies to destroy invaders by dissolving them.
other lymphocytes make antitoxins to break down poisons.
macrophages ‘eat’ and digest micro-organisms .
Platelets
Platelets are bits of cell broken off larger cells.
Platelets produce tiny fibrinogen fibres to form a net. This net traps other blood cells to form a blood clot.
Plasma
A straw-coloured liquid that carries the cells and the platelets which help blood clot.
• carbon dioxide
• glucose
• amino acids
• proteins
• minerals
• vitamins
• hormones
• waste materials like urea.
It also contains useful things like;
Types of Blood Vessels
• Capillaries:– smallest vessels – the site where gases, nutrients, and
wastes are exchanged between the blood and other tissues
• The smallest veins are venules; – carry blood back to the heart after it
passes through the capillaries – veins have much thinner walls and
much larger interior diameters than arteries
Location of Heart
Pericardial Cavity
Layers of Cardiac Tissue
Visceral pericardium • Outer protective layer composed of a
serous membrane • Includes blood capillaries, lymph
capillaries, and nerve fibers. Myocardium • Relatively thick. • Consists largely of cardiac muscle tissue
responsible for forcing blood out of the heart chambers.
• Muscle fibers are arranged in planes, separated by connective tissues that are richly supplied with blood capillaries, and nerve fibers.
• Endocardium • Consists of epithelial and
connective tissue that contains many elastic and collagenous fibers.
• Connective tissue also contains blood vessels and some specialized cardiac muscle fibers called Purkinje fibers.
• Lines all of the heart chambers and covers heart valves.
The Human Heart
• The human circulatory system returns oxygen-depleted blood from the body to the right atrium of the heart through two large veins– the inferior and superior venae cavae.
• When the right atrium contracts:– deoxygenated blood is sent to the right ventricle – it contracts and sends blood out to the lungs via
the pulmonary artery • One-way valves ensure that blood follows only this
path. After blood has circulated through the capillary beds in the lung’s alveoli:
• it becomes oxygenated – returns to the heart through the pulmonary veins
The Human Heart
• The oxygenated blood enters the left atrium:– it contracts and pushes the blood into the left
ventricle • The contraction of the left ventricle sends
oxygenated blood at high pressure out the aorta and into:– the arteries – capillaries – veins
• forms the systemic circulation
Heart Anatomy
Heart Anatomy
VALVES
bicuspid valve
aortic
semilunar valve
tricuspid valve
pulmonary
semilunar valve
Heart valvesHeart valves
The Cardiac Cycle• The contraction phase of the atria and the
ventricles:– called systole
• is coordinated with their relaxation phase – called diastole
• A cardiac cycle:– consists of one complete systole and one
complete diastole
• systolic blood pressure :– blood pressure measured in the systemic
arterial circulation at the peak of ventricular ejection into the aorta
• diastolic blood pressure:– blood pressure measured just prior to
ventricular ejection
Contraction cycle of the heart
Contraction Contraction Cycle of the Cycle of the
HeartHeart
Contraction Cycle of the Heart
Circulatory System -Gross and Cool Facts!
•The body of an adult contains over 60,000 miles of blood vessels! •An adult's heart pumps nearly 4000 gallons of blood each day! •Your heart beats some 30 million times a year! •The average three-year-old has two pints of blood in their body; the average adult at least five times more! •A "heartbeat" is really the sound of the valves in the heart closing as they push blood through its chambers.
References
AP Biology Textbook
Addison and Wesley Biology 11
Vijay Aswathy and S Morris
www.worldofteaching.com