Embed Size (px)
Citation preview
B5: TransportationTransport in Humans
Describe the circulatory system
The blood, heart and blood vessels make up the circulatory system. The heart is a muscular pump Blood is pumped around the
body in one direction There are valves in the heart
and in veins to help control the direction that blood flows
The inside of the heart is divided into two sections so that the two types of blood (oxygen-rich and oxygen-poor) are kept apart.
Remember that the heart is always labelled as if it is in a body facing you, so the right side of the heart is on the left of the diagram.
oxygen-poor blood
right sideof the heart
oxygen-rich blood
left sideof the heart
Double circulation
The two sides of the heart
Blood is pumped around the body by the heart.
It takes about 30 seconds for blood to go once around the body.
Starting with the left side of the heart, what route does the blood follow to complete one circuit of the body?
The left side of the heart pumps oxygen-rich blood to the rest of the body.
This blood supplies the body’s cells with oxygen.
What gas does the blood then pick up from the body’s cells and where does the blood go next?
body’scellsbody’scells
The oxygen-poor blood needs to lose the carbon dioxide and pick up more oxygen.
Blood picks up carbon dioxide from the body’s cells.
This oxygen-poor blood then travels back to the right side of the heart.
body’scellsbody’scellsHow does it do this?
Where does this oxygen-rich blood then travel to?
Next, the right side of the heart pumps oxygen-poor blood to the lungs.
In the lungs the blood gets rid of the waste carbon dioxide and collects more oxygen.
lungslungs
body’scellsbody’scells
The oxygen-rich blood then returns to the left side of the heart.
This completes the blood’s journey around the body.
Why is the journey of blood through the circulatory system called a double circulation?
body’scellsbody’scells
lungslungs
During one complete circuit of the body, blood passes through the heart twice.
The heart has two jobs to do and so the circulatory system involves a double circulation.
What are the two jobs that the heart carries out during this double circulation?
body’scellsbody’scells
lungslungs
The heart pumps blood around the circulatory system.
The heart is made of muscle and keeps pumping blood around your body, even when you are asleep!
muscletissue
What do the blood vessels on the outside of the heart do?
Exterior heart structure
What is the heart made of?
The heart is full of blood but also needs its own blood supply so that the muscle can keep pumping.
blood vessels supply blood to muscle tissue
The blood vessels on the outside of the heart carry oxygen-rich blood to the heart muscle cells. Oxygen-poor blood is then carried away from these cells by outer blood vessels and back into the heart.
muscletissue
♥ The inside of the heart is divided into two sections to keep oxygen-rich and oxygen-poor blood separate. ♥ Each side of the heart is also divided into two sections.
Each section of the heart is called a chamber.How many chambers are there?
right sideof the heart
left sideof the heart
4
Interior heart structure
The four chambers of the heart have special names:
♥ A lower chamber is called a ventricle.
♥ An upper chamber is called an atrium (plural atria).
rightventricle
rightatrium
leftventricle
leftatrium
The chambers of the heart have different functions.
♥ The atria collect blood that enters the heart.♥ The ventricles pump blood out of the heart.
blood tothe body
blood from the body
blood to the lungs
blood from the lungs
Describe double circulation The two sides of the heart (left and right) are separated
by the septum Blood in the right side is deoxygenated (oxygen-poor) Blood in the left side is oxygenated (oxygen-rich) the right side of the heart is less muscular as the blood
is pumped to the nearby lungs Blood is under less pressure
The left side of the heart is more muscular as the blood is pumped to the rest of the body Blood is under higher pressure
Arteries Carry blood away from the heart Except for the pulmonary artery, transport
oxygenated blood Artery walls are thick and elastic so they can
stretch under the high pressure of blood As the arteries stretch, they “pulse”
Habits of the heart – take your pulse
thick outer wall
thick inner layerof muscle and elastic fibres
narrow central tube
Veins Carry blood to the heart Except for the pulmonary vein, carry
deoxygenated blood Wider than arteries, with thinner walls
Blood under lower pressure Valves prevent the back-flow
of blood thin outer wall
thin inner layerof muscle and elastic fibres
wide central tube
Valves
backflow prevented
vein valve closedblood to
the heart
vein valve open
When blood flows along veins it pushes past
the valves, which can only open in one direction.
If blood in a vein does flow backwards,
it is trapped by closed valves.
When valves go bad!!
Varicose veins
Capillaries Capillaries are the tiny blood vessels that carry
a blood supply to and from the body’s cells.
artery vein
Capillaries are the only blood vessels where substances can be exchanged between the blood and body cells.
The heart beat All the parts of the heart on
either side, work together in a repeated sequence.
The two atria contract and relax; then the two ventricles contract and relax.
This is how blood moves through the heart and is pumped to the lungs and the body.
One complete sequence of contraction and relaxation is called a heartbeat.
Sequence of a heart beat
The heart beat When the heart muscles
are relaxed – diastole Blood flows from veins into
atria When the heart muscles
contract – systole Atria contract first to pump
blood into ventricles (valve between atrium and ventricle opens)
Ventricles contract to pump blood into the arteries(forces valve to shut)
Normal blood pressure:120 Systolic pressure 80 Diastolic pressure
Coronary heart disease Use pp 106-107 in your text books to read about CHD. Write notes to:
Describe the nature of CHD State the possible causes of CHD Describe some methods of preventing CHD
Pulse rate Read “the heart and exercise” p 105 of your
textbook In pairs, compete the practical on p105 to
investigate the effect of exercise on pulse rate. Stopwatches are available Draw up a results table in your notebook to show your
resting heart rate compared to your HR after completing the various activities
Explain your results (think about the purpose of blood supply to your muscles)
Blood The liquid part of the circulatory system Blood cells are suspended in plasma An adult human has about 5.5L of blood in
their body
plasma
white blood cells and platelets
red blood cells
The four components of blood
red blood cell
white blood cell
platelet
Blood plasma carries three types of blood cells. They have different shapes and carry out
different functions.
Components of blood
Micrographs of blood
Scanning electron micrograph of blood
Red blood cell
White blood cell
Platelet
The most common type of blood cell. Made in the bone marrow Transport oxygen from the lungs to the body’s
cells, where it is used in respiration.
Red blood cells
oxygen
A red blood cell has several features that help it do its job:
Disc-shaped, witha dent on each side,
creates a large surface area for
gas exchange.
A large surface area compared to
volume, so oxygen is always close to the
surface.
It has no nucleus, so there is more space for haemoglobin and
so more oxygen.
It contains haemoglobin,
a special pigmentthat combines with oxygen.
Another important feature of a red blood cell is its size.
The diameter of a red blood cell is slightly bigger than the average diameter of a capillary.
This forces the RBC to slow down as it passes through a capillary.
The surface of the RBC is exposed to the surface of the capillary so gas exchange occur.
haemoglobin
haemoglobin
Haemoglobin is the special pigment in red blood cells.
At the lungs, oxygen diffuses into red blood cells and combines with haemoglobin to form oxyhaemoglobin
This is how red blood cells are able to bind to oxygen and carry it in the blood.
Oxyhaemoglobin makes red blood cells appear bright red.
oxygen
oxygen++
oxyhaemoglobin
oxyhaemoglobin
++oxyge
noxyge
n
haemoglobin
haemoglobin
Red blood cells loaded with oxyhaemoglobin carry oxygen from the lungs to the body’s cells.
Here, oxyhaemoglobin changes back to haemoglobin and oxygen is released.
oxyhaemoglobin
oxyhaemoglobin
Oxygen is then able to diffuse into the body’s cells.
(not to scale)
oxygen +haemoglobin
oxygen +
haemoglobin
oxyhaemoglobinoxyhaemoglobin
oxygen +haemoglobin
oxygen +
haemoglobin
(not to scale)
oxyhaemoglobinoxyhaemoglobin
oxygen +haemoglobin
oxygen +
haemoglobin
oxyhaemoglobinoxyhaemoglobin
(not to scale)
haemoglobinhaemoglobin+ oxygen + oxygen
oxyhaemoglobinoxyhaemoglobin
haemoglobinhaemoglobin+ oxygen + oxygen
oxygen +haemoglobin
oxygen +
haemoglobin
oxyhaemoglobinoxyhaemoglobin
(not to scale)
oxyhaemoglobinoxyhaemoglobin
Red blood cells in an alvelous
Red blood cells in a capillary bed
White blood cells The largest type of blood cell. They have a large nucleus and can change their shape.
White blood cells protect the body from disease by fighting invading microbes that can cause infection.
White blood cells can squeeze through the walls of capillaries.
Different types of white blood cells protect the body in different ways:
Phagocytes fight against infection by surrounding invading microbes and then digesting them!
Lymphocytes produce antibodies to fight against infection.
White blood cell count
Unwell:white blood
cell number is high
Healthy:white blood cell count is
low
Doctors can check the number of white blood cells in a person’s blood to find out if they are healthy or fighting off an infection.
Platelets are cell fragments that have broken off from other larger cells.
They are much smaller than red and white blood cells and do not have a nucleus.
platelet
Platelets Important for blood clotting.
Platelets help to make tiny fibres that form a net at the site of a cut.
11 The clot dries and forms a scab which protects the cutwhile new skin grows.
33
Red blood cells are trapped in this net forming a blood clot.
22
Why is it important not to pick a scab?
Plasma Liquid part of blood that makes
up 55% of blood volume Water with lots of things
dissolved in it: Nutrients: glucose, amino acids,
lipids, vitamins and mineral ions Wastes: carbon dioxide and urea Antibodies Hormones: insulin, adrenaline,
glucagon
Which type of blood cell?
Multiple-choice quiz
