A short description about all the systems in the body.

1. THE BODY
SYSTEMS
CEIP ALMIRANTE LAULHÉ
(San Fernando)

2. Digestive system
Stage 1
It begins in the mouth,
where our teeth break down
food. While we chew, the
food mixes with saliva. This
mixture is called a bolus.
Stage 2
The bolus reaches the
stomach, which produces
gastric juices. These juices
form a thick mixture called
chyme.
Stage 3
The chyme travels to the
small intestine. which
produces intestinal juices.
These juices turn * the
chyme into a liquid called
chyle.
Digestion is the process of breaking down* food into nutrients. It usually takes our body 24 to
48 hours to digest food. Digestion takes place in the digestive system. It consists of one long
tube, called the digestive tube, and the helper glands*.
These are the stages of digestion:
* Breaking down: descomposición
* To turn into: convertir
* Helper glands: glándulas digestivas

3. Digestive system
Nutrients are absorbed into the blood in the small intestine.
In the large intestine , the remaining undigested food turn into
faeces.
Faeces leave the body through the anus.

4. Respiratory system
Respiration is the process by which we
breathe in, or inhale, to obtain the oxygen
our body needs, and we breath out, or
exhale, to expel the carbon dioxide our body
produces. Respiration takes place in the
respiratory system. It consists of the air
passageways * and the lungs.
* Air passageways: vías respiratorias
* Branches: ramificaciones
When we inhale, air enters through the
nostrils , goes to the pharynx, then travels
down the larynx and the trachea. The trachea
is divided into two branches * called the
bronchi. The bronchi take the air to each lung.

5. Respiratory system
Inside the lungs, the bronchi are divided into smaller
branches called bronchioles. The bronchioles lead to
the air sacs.
The oxygen in the air we inhale passes from the air
sacs into the blood. The blood carries the oxygen to
all the cells in our body.
The carbon dioxide produced by our body passes into
the air sacs.
The air sacs expel the carbon dioxide when we exhale.

6. Circulatory system
Blood
Blood is a liquid substance in
our body that reaches all the
body cells.
Blood vessels
Blood vessels are tubes which transport blood
throughout the body. There are three types:
Arteries carry blood away from the heart
towards all body tissues.
Veins carry blood back to the heart from all body
tissues.
Capillaries have very thin walls. This allows for
nutrients and oxygen to pass into the body cells,
and for carbon dioxide to leave the cells.
The heart
The heart is a special type of muscle.
It acts as a pump * to send blood
around the body through the blood
vessels. The heart has four chambers:
- the right and left atria* , where
blood enters the heart.
- the right and left ventricles, where
blood leaves the heart.
The circulatory system consists of blood, blood vessels and the heart.
* Pump: bomba
* Atria: aurículas

7. Circulatory system
Circulation is the movement of blood through the
circulatory system.
Blood carries * nutrients and oxygen to all parts of the
body. It also collects * carbon dioxide and other waste
products which need to be eliminated.
Blood moves constantly in the circulatory system.
* To carry: llevar
* To collect: recoger

8. Excretory system
Excretory system
The excretory system consists of the kidneys,
the ureters, the bladder and the urethra.
Excretion happens when blood reaches the
kidneys. The kidneys filter the blood, retain
waste products and use them to produce
urine.
Then, the ureters carry urine from the kidneys
to the bladder. Urine is stored in the bladder
until it leaves the body through the urethra.
Excretion is the elimination of waste products from the blood.
Excretion takes place in the excretory system and the sweat glands.

9. Sweat glands
Sweat glands are long, coiled* tubes that are located
inside the skin. Each sweat gland connects to a pore
on the surface of the skin.
Sweat is formed in the sweat glands. It consists mainly
of water, but it also contains mineral salts and waste
products. When sweat is secreted through pores
waste products are eliminated. This is why sweat
glands are considered part of the excretory system.
* Coiled: enrollado
pore
sweat
gland

10. Nervous system
The central nervous system
It has two parts:
-The brain: protected by the craneum. It has
three parts:
● The cerebrum controls voluntary actions, like
running or talking.
● The cerebellum controls movement,
coordination and balance.
● The brain stem* controls internal organ
activities that we don’t need to think about,
like breathing.
-The spinal cord: a long, thin bundle* of nervous
tissue. It extends from the base of the brain to
the bottom of the spine, and connects the brain
and the peripheral nervous system.
The peripheral nervous system
consists of nerves that extend
thoughout the body. It connects the
central nervous system to our sense
organs, muscles, internal organs, etc.
There are two types of nerves:
- Sensory nerves: they receive
messages from receptors in the sense
organs and send these messages to the
central nervous system.
- Motor nerves: they send orders from
the central nervous system to the other
organs.
The nervous system carries out the function of sensitivity. The nervous system is made up of
two parts:
* Brain stem: bulbo raquídeo
* Bundle: haz, conjunto

11. Locomotor system
The skeletal system
The skeletal system gives
our body its shape and
protects delicate organs.
There are over 200 bones in
our body. All bones are hard
and rigid.
The ends of bones are
covered by a soft, elastic
tissue called cartilage.
Bones meet at joints, and
are held together by
ligaments.
The muscular system
The muscular system consists of
all the muscles in the body.
Muscles are organs which can
change in lenght and shape.
When a muscle is relaxed, it is
long and thin. When a muscle is
contracted, it is shorter and
thicker.
There are about 640 muscles in
our body. Muscles are joined to
bones by tendons.
The locomotor system consists of the skeletal system and the muscular system

12. ovum (ova)
Reproductive system
Female sex cells
Females sex cells are called ova. These are their
main characteristics:
- They are found in the ovaries from birth.
- They are large, round cells thart can be seen
with the naked eye.
- They contain all the nutrients required for the
development of an embryo.
- They mature during puberty.
Male sex cells
Male sex cells are called spermatozoa.
These are their main characteristics:
-They are produced on testes, starting
at puberty.
-They are very small and can only be
seen under a microscope.
-They have a small head and a long tail
which they use to move.
The reproductive system carries out the function of reproduction. There are two different
types of cells in this system:
spermatozoa

13. Fertilization
Fertilization occurs when a sperm cell joins* with an
egg cell.
During sexual intercourse* , semen is released into the
woman’s vagina. The spermatozoa travel through her
uterus into the Fallopian tubes. If an egg cell is
released from one of the ovaries, fertilization can
occur.
As a result of fertilization, a new cell, called a zygote,
is formed. The zygote divides and forms an embryo.
The embryo attaches* itself to the wall of the uterus
and continues to grow.
* To join: unir
* Intercourse: relación sexual
* To attach: pegarse

14. Let’s review some concepts
Nutrition
This vital function is carried out
by:
- Digestive system
- Respiratory system
- Circulatory system
- Excretory system
Sensitivity
There are various organs and
systems involved in this vital
function:
- Sense organs
- Nervous system
- Muscular system
- Skeletal system
Reproduction
This vital function is carried out
by the reproductive system, both
male and female.
All of these systems work together so the organism
functions correctly.