This is a full reviewer for Grade 6 pupils in Science subjects for the Second Quarter Examination.

1. DIGESTIVE SYSTEM
 Digestions – This process of breaking down food into nutrients for
the use of body cells.
 Digestive System-is made up of groups of organs that work
together to digest food so the body can use it.
 Mouth - - where digestion begins.
 Teeth –cut the food into small pieces, the tongue helps the food
move into small pieces, and the tongue helps the food move in the
mouth while chewing.
 Tongue – Helps push the food into the esophagus when
swallowing.
 Saliva – it is the one that softens and moistens the food when
chewing.
 Amylase - Enzymes that contain saliva that digest starch.
 Esophagus – is a long straight muscular tube that connects the
mouth to the stomach.
 Peristalsis – the squeezing movement of muscles.
 Stomach – muscular baglike organ at the end of the esophagus.
 Stomach – It secretes acid and enzymes to digest food and mixes it
with gastric juices through peristalsis until it becomes a thick, soupy
mixture.
 Chyme – This is a thick, soupy mixture of partly digested food.
 Small intestine – is a narrow-folded tube about 2.5 cm wide and 7m
long.
 Liver – releases bile which is stored in the gall bladder.
 Bile – helps digest fats.
 Pancreas – releases pancreatic juices that help in the digestion of
carbohydrates, fats, and proteins.
 Vili- A tiny fingerlike projection in the lining of the intestinal wall
 Large intestine – Where undigested food stays and is eliminated
through the anus.
 Feces or stool – the solid waste.
 Defecation or bowel Movement – The process of elimination of
solid waste by the body.
 Rule of the teeth in digestion:
- Start of digestion process
- Adult has 32 permanent teeth: eight incisors, four canines,
eight premolars, and 12 molars.
- Food rich in calcium and vitamins C and D are good for your
teeth.
RESPIRATORY SYSTEM
 Respiratory System – The body system that helps you breathe.
 When you breathe, you inhale oxygen and exhale carbon dioxide.
 Nose- Where breathing starts. About 20 times a minute you take in
air through the nose.
 Nostrils- the two openings of the nose.
 Nasal Cavities – A pair of cavities separated by septum.
 Cilia – Filter and trap dust and dirt in the air and the mucus warm
and moisten the air that you breathe in.
 Pharynx – is a tube about 13 cm long, found at the back of the
throat.

2.  2 Tubes of Pharynx
- Esophagus – leading to the stomach.
- Trachea – leading to the lungs.
 Voice Box – contains vocal cords.
 Larynx – is a boxlike structure.
 The air passing over vocal cords may cause them to vibrate, thus
producing SOUNDS.
 Trachea or windpipe – trap the dirt and dust and sweep them away
from the lungs by coughing or sneezing.
 Bronchi or bronchial tubes – short tubes that direct air into the
right and left lungs.
 Bronchioles – each bronchial tube branches into smaller tubes.
 Alveoli – The bronchioles lead into tiny air sacs.
 Capillaries – Tiny blood vessels that surround the alveolus.
 Lungs – are the major organ of the Respiratory System.
 THE RIGHT LUNGS ARE DIVIDED INTO 3 PARTS CALLED LOBES.
 THE SMALLER LEFT LUNG IS DIVIDED INTO 2 LOBES.
 Pleura – a thin membrane that surrounds the lungs.
 Rib Cage – It is the one that protects the lungs.
 There are 12 pairs of rib cage protecting the lungs.
 The lungs have a spongelike quality and pinkish color.
 Diaphragm – a dome-shaped muscle that works with your lungs to
allow you to breathe in and breathe out.
 Diaphragm – separates the chest cavity from the abdominal cavity.
 Diaphragm – It is the main muscle for breathing.
CIRCULATORY SYSTEM
 Circulatory or Cardiovascular System – considered as the main
transport system of the body. Like a network Highways that
connects all the organ.
 MAJOR PARTS: HEART, BLOOD VESSELS, AND BLOOD
 Apex- the lowest part of the heart
 Heart – a specialized muscular organ located on the left side of the
chest.
 Pericardium – a thin but very strong sac in the air that we breathe.
 Atria – the receiving chambers
 Ventricles – the pumping chambers
 The main function of the heart is to pump blood to the lungs and
the body cells.
 Heart pumps approximately 5 liters of blood per minute.
 The heart beats between 60 – 100 times per minute.
 The sound the heartbeat represents as lubb-dubb-pause-lubb-dubb
 Stethoscope - the heartbeat can be heard using this instrument.
 Blood Vessels – are like roadways of the body where blood passes
through.
 Arteries – carry blood away from the heart to the body cells.
 Aorta – biggest artery.
 Arteriors – smaller artery.

3.  Capillaries – have very thin walls that allow the food nutrients and
oxygen molecules to easily pass through.
 Blood – protein-rich fluid circulating in the body.
 Blood plasma – 55% of the blood. It also delivers the nutrients to
the cells.
 Red Blood Cells RBCs- are tiny biconcave disks.
 Erythrocytes - most abundant cells in the blood.
 Hemoglobin – An iron-containing protein contains in blood vessels.
 120 days – life span of red blood cells.
 White blood Cells WBCs – or Leukocytes – are generally larger or
lesser than red blood cells.
 Platelets or Thrombocytes – are the smallest element in the blood
that plays an important role in blood clotting.
 Fibrin – Clotting protein.
 Clot – jelly-like red mass.
 Blood circulation- the movements of blood as it distributes food
and oxygen to the body cells and removes waste materials.
 Pulmonary Circulation – the pathway of blood from the heart to the
lungs and back to the heart.
 Systematic Circulation – The pathway of the blood from the heart of
the others parts of the body and back to the heart.
 Pulmonary arteries – are the only arteries in the body that carry
oxygen-poor blood.
 Blood picks up oxygen and gets rid of carbon dioxide.
 Pulmonary veins- are the only veins that carry oxygen-rich blood.
 Oxygen - burns the food nutrients in the cells and energy is
produced.
 Coronary Circulation – It is responsible for the transport of Food
nutrients and oxygen to the muscle tissues of the heart.
 Urine – The unwanted substances such as excess water, salt, urea
uric acid, and other chemicals.
 Blood Pressure – it exerts force inside walls of the blood vessels.
 Sphygmomanometer – measures the blood pressure.
 Diastolic Pressure – is the low pressure of the heart that occurs
when it is relaxed.
NERVOUS SYSTEM
 Nervous System – is the control system of the whole body.
 Two divisions: CNS or Central Nervous System and PNS Peripheral
Nervous System.
 CNS or Central Nervous System – is made up of brain and spinal
cords which process all incoming and outgoing messages in the
body.
 PNS or Peripheral Nervous System – consist of cranial nerves and
spinal nerves.
 Cranial nerves – are 12 pairs of nerves. these nerves are associated
with motor and sensory functions.
 Spinal Nerves – are 31 pairs of nerves. This supply communication
links between the central nervous system and the neck, trunks,
arms, and legs.
 Neuron –nerve cells that serve as the functional unit of the nervous
system.
 Cell Body – is the enlarged portion that contains the nucleus.

4.  Dendrites – Receive information from the other cells.
 Axon – Conducts nerve signals away from the body.
 Synapse – the gap between axon and dendrite.
 Neurotransmitter – allows nerve impulses to transfer to the next
cells.
 Receptors – carry sensation from the outer part of the body to the
central nervous system.
 Stimulus- anything that receptors of the sense organs collect from
the environment.
 Impulse – the electrical messages that pass through the neurons.
 Sensory Nerve – A bunch of neurons bundled together.
 Brain - the largest organ in the nervous system.
 Cerebrospinal fluid (csf) – acts as a shock absorber to help prevent
injury.
 Cerebrum – The largest part of the brain
 Cerebellum- small cauliflower-like structure is the second largest
part of the brain.
 Medulla oblongata – It relays information between the spinal cord
and the brain.
 Midbrain- act as a cellular switch board to keep the different areas
of the brain communicating continuously.
 Hypothalamus- regulates body function such as thirst and hunger.
 Pons – specialized bond of nerve fibers that connect midbrain with
oblongata.
 Spinal cord – made up of nerve fibers that carry information to and
from the brain.
 Spinal cord – information highway of the central nervous system.
 Vertebrates- bones that protect spinal cords.
 Hormones – chemical substances produced by the body that
influence and regulate body activities.
 Pituitary glands- is the main endocrine gland that is located at the
base of the brain.
 Reflex action – a quick response that you cannot control.
