Human Health And Systems

Question 1

Ingestion/Eating

Answer 1

Food is taken in by the body

Question 2

Digestion

Answer 2

Food is broken down

Question 3

Absorption

Answer 3

Digestion food passes into the blood stream

Question 4

Assimilation

Answer 4

Using the food in the cells of the body

Question 5

Elimination

Answer 5

Getting rid of undigested food

Question 6

Physical Digestion

Answer 6

Mouth(Teeth) Stomach(Churning)

Question 7

Plasma

Answer 7

• Liquid part of the blood
• Pale yellow – mostly water
• Function : to transport chemicals and heat
– Chemicals (Useful): Food, Hormones
– Chemicals (Waste): CO2, Salts, Urea
– Heat: Generated from chemical reactions,
transported around to maintain 37°C
• Also carries the red blood cells, white blood
cells, and platelets.

Question 8

Red Blood Cells

Answer 8

• Round, flattened discs, curve inward
near centre
• Small, no nucleus, formed in bone
marrow
• Very numerous – approx 5million per drop
blood
• Function : transport oxygen to cells
• Red colour comes from haemoglobin
they contain.
• Haemoglobin picks up oxygen in the
lungs
• It later releases it in other parts - e.g.muscle

Question 9

White Blood Cells

Answer 9

• Larger than Red Blood Cells
but fewer in number
• No definite shape – shape
can change
• They are also made in the
bone marrow
• Function : to fight infection
• Some can surround micro-organisms and destroy them
• Others produce proteins called antibodies
• Antibodies help to destroy micro-organisms such as
bacteria

Question 10

Platelets

Answer 10

• Smaller than red or white blood
cells
• They are formed in the bone
marrow
• They are formed from larger
cells breaking down into pieces
• Function: help to form blood
clots
• When a blood vessel is injured, platelets help to form a clot
• Clotting prevents loss of blood, and prevents micro-
organisms getting in
• Clots are temporary barriers while repair and healing is
taking place

Question 11

System of Tubes + Pump

Answer 11

Blood being a fluid, needs tubes in
which to flow
• These tubes are called blood
vessels
• They come in three main types:
– Arteries
– Veins
– Capillaries
• Good blood flow requires the aid of a good pump
• In the human circulatory system this pump is the heart
• In an average lifetime, the heart beats more than 2.5 billion
times, without ever pausing to rest

Question 12

Arteries

Answer 12

• Carry blood AWAY from the heart
• Flow of blood is strong and at high pressure
• Artery walls are thick and strong to withstand this
pressure
• Blood is under pressure – forced to move in one direction
• There is no need for valves in arteries to prevent
backwards flow
• All arteries (except pulmonary artery) carry oxygenated blood

Question 13

Veins

Answer 13

Carry blood BACK to the heart
• Flow of blood is weaker and pressure is low
• Vein walls are thinner and weaker than artery walls
• Pressure is low, so there is a danger of backward flow of
blood, especially when flow direction is against gravity
• Valves in veins at regular intervals, allow blood to flow
forwards, but prevent reverse flow
• All veins (except pulmonary vein) carry deoxygenated blood

Question 14

Capillaries

Answer 14

These are tiny blood vessels
• There are a huge number of them in the body
• Capillaries are found between arteries and veins
• Capillaries have very thin walls which allow materials to
pass in and out with the surrounding cells and tissue.

Question 15

The Heart

Answer 15

• Is an organ about the size of a
clenched fist
• Function: pumps blood around
the body
• It pumps blood by contracting
periodically
• Cardiac muscle provides the
contraction
• Unlike regular muscle, cardiac muscle doesn’t tire easily
• Resting heart rate in adults is about 72 bpm(beats per minute)
• In exercise, the heart beats faster, so that the blood can
carry chemicals faster around the body e.g. Oxygen

Question 16

Pulse Rates

Answer 16

• When the heart contracts, it
squeezes blood into the arteries
under pressure.
• As blood flows down the arteries,
surges of pressure can be felt where
the arteries are close to the surface
• Areas where it can be felt are:
– At the wrist
– Inner arm near elbow joint
– At the sides of the neck
• A surge of blood felt at these locations is called a pulse
• The pulse rate is at the same pace as the heart rate

Question 17

Two Blood Circuits

Answer 17

• The human circulatory system has
what is known as Double Circulation
• Blood passes through the heart twice
on its journey around the body
• It consists of two circuits:
• 1: Pulmonary Circulation
– Blood leaves the heart
– goes to the lungs to become oxygenated
– returns to the heart
• 2: Systemic Circulation
– Blood leaves the heart
– travels to other parts of the body
– returns to the heart

Question 18

Structure of the Heart

Answer 18

• The heart is split down the
middle into two sides by the
septum
• Each side has an upper
chamber called an atrium
(plural atria)
• Each side also has a lower
chamber called a ventricle.
• This makes a total of 4
chambers
• Valves between the upper
and lower chambers ensure
that blood only flows in one

Question 19

Left versus Right

Answer 19

• Heart diagrams are
always shown as if facing
the person
• The left side of the heart
appears on the right of
the diagram, and vice
versa
• The left side of the heart always pumps oxygenated
blood (shown in red), received from the lungs, and pumps it
to the body.
• The right side always pumps deoxygenated blood (shown
in blue), received from the body, and pumps it to the lungs

Question 20

Blood Vessels of The Heart

Answer 20

• The vena cava (veins)
bring blood from the body
into the right atrium.
• The right ventricle pumps
blood into the pulmonary
artery, which leads to the
lungs.
• The pulmonary vein returns blood from the lungs to the
left atrium.
• The left ventricle pumps blood into the aorta (an artery)
which leads to all other parts of the body.
• Both the pulmonary artery and the aorta have valves at the
base to prevent blood flowing back into the heart.

Question 21

Pharynx

Answer 21

• This is the scientific name for your throat
area.

Question 22

Trachea

Answer 22

This is the tube that leads into your lungs.
• It is very strong and is kept open by Rings
of Cartilage.

Question 23

Bronchus

Answer 23

• As we have two lungs our Trachea divides
to branch into each one.
• These two branches are called Bronchi.

Question 24

Bronchioles

Answer 24

• To spread out through all our lungs the
bronchi break up to even smaller little
branches called BRONCHIOLES.

Question 25

Alveoli

Answer 25

• The final place the air we breathe in goes to
in our lung is the ALVEOLI.

Question 26

Gas Exchange

Answer 26

• It is in the Alveoli that Carbon Dioxide is
brought into the lungs to be exhaled and
oxygen is brought into the body for
respiration.
• This is called Gas exchange.

Question 27

Alveolus

Answer 27

This is how they got the name
Alveolus from the Greek word meaning
“bunch of Grapes”!

Question 28

Capillaries

Answer 28

Tiny, tiny blood vessels known as
capillaries carry blood to and from the
alveoli and allow the gases to pass in and
out.