Science: Structures and Systems of the Human Body

Question 1

True or false: organs are made up of tissues

Answer 1

True

Question 2

Describe the organs of the respiratory system and their functions, starting from breathing in

Answer 2

Air enters the body through the nose or mouth.

Air then floats through the throat and into the trachea (wind pipe).

The trachea divides into two tubes, with air going to the 2 main parts of the lung.

Inside the lung, the tubes branch into smaller and smaller tubes until they form tiny sacs.

Inside the sacs, oxygen from the air is added into the blood while waste from the blood is extracted and eventually expelled from the lungs in the air that is breathed out.

The diaphragm causes air to move in and out of the lung.

The muscular system (causing organs to move), nervous system (sending/receiving instructions from the brain to move), circulatory system (moving blood through the lungs) and skeletal system (protecting the organs) are also involved in this process.

Question 3

What are the main parts of the circulatory system?

Answer 3

The heart, blood and blood vessels.

Question 4

True or false: veins carry blood away from the heart.

Answer 4

False.

Veins carry blood back to the heart, while arteries carry blood away from the heart.

Question 5

How do the circulatory and respiratory systems work together?

Answer 5

The respiratory system works to bring in air and oxygen that we need to survive, while the circulatory system works to pump blood in and out of the lungs so that the oxygen is transported from the lungs to the rest of the body.

Question 6

What do capillaries do?

Answer 6

They are tiny blood vessels that can carry blood to cells, which delivers oxygen and other nutrients that the cells need to function.

Capillaries also carry away oxygen-poor poor blood used by the cells and waste produced by the cells into veins, which then carry that blood back into the lungs to be expelled from the body.

Question 7

Why does the heart beat faster during exercise?

Answer 7

During exercise, muscles need more oxygen and nutrients (and produce more waste) because they are working harder, so the brain tells the heart to beat faster to pump more oxygen and nutrients to the muscles (and to remove the built up waste).

Question 8

The circulatory system starts to break down when, for example, the heart gets weak or arteries get narrower as people get older or because of diseases.

What do you think happens to the body when the circulatory system starts to break down?

Answer 8

Less oxygen and nutrients delivered to cells means that cells cannot function properly, which means the body will get weaker when certain organs and muscles do not work as well.

And, when waste is not removed very effectively from cells, the cells could start to malfunction as well, because waste builds up over time.

Common circulatory disorders include heart failure, heart attacks and high blood pressure, which become more common as people get older.

Question 9

True or false: bones are made up of both living tissues and non-living materials.

Answer 9

True, bones are also made up of non-living minerals.

Question 10

What are the 3 types of muscles that make up the muscular system?

Answer 10

Smooth muscles are found on body organs such as the stomach.

Skeletal muscles are attached to the bone by tendons, to make bones move by pulling on them.

Cardiac muscles make up the heart.

Question 11

True or false: muscles can only pull on bones by contracting, but can’t push.

Answer 11

True. This is why muscles need to work in pairs to move bones back and forth.

Question 12

When you run, how do the major systems work together and how does each function?

Answer 12

Muscles contract to move bones, helping you move your legs to run.

The respiratory system and circulatory system work together to deliver more oxygen needed by muscles in order to run. And they also work together to collect extra waste produced by cells when they work harder to help you run, and then excrete them.

The skeletal system supports the body as legs hit the ground.

The brain and the nervous system coordinates all the systems so they work together to help you run.

Question 13

True or false: skin is the largest organ.

Answer 13

True.

Question 14

What is the skin’s function?

Answer 14

It covers and protects internal organs.

It keeps disease causing germs from entering the body.

It sweats to help the body regulate temperature.

Question 15

What are the sensory organs?

Answer 15

Eyes
Nose
Ear
Skin
Tongue

Question 16

What are key parts of the central nervous system?

Answer 16

The brain and the spinal cord

Question 17

What is the difference between motor nerves and sensory nerves?

Answer 17

Motor nerves carry messages from the brain to other parts of the body, while sensory nerves carry messages from sensory organs and other body parts to the spinal cord

Question 18

How does the digestive system work when you eat something? Trace the food from the time it enters your mouth through the large intestines.

Answer 18

Mouth: teeth tear and crush food, and saliva begins to chemically break down the food.

Esophagus: food passes through this tube to the stomach.

Stomach: churns and stomach acids further break down food before it passes to the small intestine.

Small intestine: this is where most of the digestion occurs, where digested food enters capillaries that are connected to larger blood vessels that carry nutrients to other parts of the body.

Liver: connected to the small intestines, sends certain digestive juices to the small intestine to break down fats.

Pancreas: sends certain digestive juices to the small intestine to break down protein, and also produces chemicals tp adjust sugar levels in the blood.

Large intestine: absorbs water, before passing waste to the colon.

Question 19

Diabetes is a disease where blood sugar levels get too high. Which digestive organ do you think is not functioning when someone has diabetes?

Answer 19

The pancreas.

The pancreas produces something called insulin to help move glucose (sugar) from blood to cells. In people with diabetes, the pancreas produces too much or too little insulin, or when cells stop responding to insulin, and sugar levels in blood get too high.

Question 20

Where is food broken down in the digestive system:

(a) Mouth
(b) Esophagus
(c) Stomach
(d) Small intestine
(e) Bladder

Answer 20

(a) Mouth: saliva starts to break down food

(c) Stomach: stomach acids help to break down food

(d) Small intestine: digestive juices from pancreas, liver and the small intestine itself help to break down food

Question 21

How do circulatory system and digestive system work together to help the body?

Answer 21

The digestive system breaks down food so that cells have the nutrients needed to function properly. The circulatory system pumps blood through the digestive system to collect nutrients and deliver them to cells in all parts of the body.

Question 22

How does the excretory system produce urine (pee), and why is this important?

Answer 22

Cells produce waste that must be removed form the body.

As blood flows through the kidney, capillaries in the kidney filters and removes waste from the blood. The waste is combined with water to produce urine, and travels through ureter tubes to a muscular sac called the bladder. When the bladder fills up, it is then released from the body when you pee.

Question 23

True or false: lungs are also part of the excretory system.

Answer 23

True.

Lungs are a vital part of the respiratory system, but they are also part of the excretory system because they help to release CO2 (which is a waste product produced by the body) from the body when breathing out.

Question 24

True or false: a fever is a type of defense mechanism.

Answer 24

True. The body’s immune system increases body temperature in order to kill germs.

Question 25

How to tiny hairs and mucous in the nose and windpipe help protect us?

Answer 25

They trap germs that come in through the mouth and nose before they enter the body. Saliva helps to kill some of these trapped germs.

Question 26

How does the skin and blood work together to protect against germs?

Answer 26

Skin keeps out germs from the body. But when germs do get in, for example when the skin is cut, white blood cells in the blood can surround and fight the germs.