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Question 1

Identify the process that occurs in the walls of the small intestine?

Answer 1

The process that occurs in the walls of the small intestine is called villi.

Question 2

Oesophagus

Answer 2

The Oesophagus is a tubular muscle that forces food down to your stomach in a process called peristalsis

Question 3

Stomach

Answer 3

The stomach stores food for about 3 hours while it uses gastric juice (stomach acid) to help digest the food. The food in your stomach looks nothing like what you ate for dinner. It is very runny, warm & smelly & has a totally different taste. This mixture is called Chyme
The human stomach is J-shaped and spends its time churning its contents round and round, with muscular walls pulling in
all directions. The stomach is filled with gastric juices made of hydrochloric acid and enzymes. The cells lining the inside of the stomach produce mucus to stop the acid burning the stomach walls.

Question 4

Liver and gall bladder

Answer 4

The liver makes a mixture of chemicals called bile. Which is used to digest fat and neutralise (deactivate) stomach acid. The bile is stored in the gall bladder until food reaches the small intestine. Bile is then released into the small intestine through a tube called the bile duct. Food does not travel through the liver.

Question 5

Pancreas

Answer 5

The Pancreas makes pancreatic juice, which contains a mixture of digestive enzymes and also neutralises stomach acid. Food does not travel through the pancreas.

Question 6

Teeth and Mouth

Answer 6

The teeth are responsible for the physical breakdown of food and the tongue is important in pushing the food towards the teeth. Salivary glands make saliva, which contains enzymes to start chemical digestion.

Question 7

Describe what urea is?

Answer 7

Urea is ammonia turned into a safer substance

Question 8

Recall the structure that attaches muscles into bones

Answer 8

A tendon is a fibrous connective tissue which attaches muscles to bone.

Question 9

Recall where red blood cells are made.

Answer 9

Our bodies are constantly making red blood cells, this occurs in the bone marrow of the long bones and in the liver of embryos.

Question 10

Identify the type of cell division that results in the formation of sperm and ova

Answer 10

The cell division is meosis

Question 11

Name the structure in which exchange of gases occurs in human lungs

Answer 11

The process involved in gaseous exchange occur in the lungs.
Oxygen enters the from the air we inhale and carbon dioxide leaves the blood and exhaled.

Question 12

Recall the two main roles of the liver

Answer 12

The liver produces a mixture of chemicals called bile, which is used to digest fat and neutralise stomach acid.

Question 13

Small Intestine

Answer 13

The small intestine is called small because it is quite narrow. If you laid a small intestine out in a straight line, it would be approximately 5 m long. The intestines are really important because they absorb the nutrients that all the cells of the body require. The ability to absorb nutrients is increased by projections, called villi, along the inner wall of the intestine that increase the surface area for absorption. Bacteria in the small intestine also help with digestion. Chyme takes about 5 or 6 hours to pass through the small intestine.

Question 14

Large Intestine

Answer 14

The large intestine is also called the colon and is wider but shorter than the small intestine. The large intestine is approximately 1.5 m long. By the time the chyme reaches the large intestine, most nutrients have been absorbed into the bloodstream. However, some vitamins are absorbed from the large intestine. Water is also absorbed into the bloodstream from the large intestine. Chyme stays in the large intestine for up to 14 hours, or sometimes longer.

Question 15

Rectum and Anus

Answer 15

The rectum is the final part of the journey for what is now solid, undigested food, or faeces. The rectum stores faeces until it starts to become full. As the rectum starts to stretch, messages are sent to the brain to make you realise thet you need to go to the toilet. Rectal muscles push the faeces out of the ring of muscle at the end of the rectum called the anus.

Question 16

Digestion

Answer 16

Digestion is the process by which foods (and drinks) are broken down and absorbed into your blood for transport to your cells. Food provides us with the materials for energy, growth and repair. The food we eat is broken down into smaller chemicals, called nutrients, by our digestive system.
Nutrients provide nutrition to the body.
They are mostly soluble substances that are
absorbed by the blood and circulated around
the body. Different types of foods provide us
with different nutrients. The function of the Hard palate digestive system is to break down food into substances that can be transported around the body.

Question 17

Humans as Functioning Organisms

Answer 17

Compared with flowering plants, humans are very active, so the requirements of our cells for energy and oxygen and the removal of toxic wastes are much greater than those of plants. As multicellular organisms, our bodies are composed of cells that must work together in order to ensure their own survival and the survival of the organism. Cells are specialised to take on specific roles. Cells with similar structures and functions group together to form tissues, different tissues work together to form organs, and different organs work together in organ systems to carry out vital functions that keep us alive.

Question 18

Blood Vessels

Answer 18

Blood travels through tubes called blood vessels. Blood vessels have different sizes and structures depending on the amount of blood they need to carry as well as the speed of the blood and whether it is picking up or dropping off substances.
Arteries (see Figure 2.32) have thick, muscular walls to cope with high pressure and to squeeze the blood along. Arteries travel away from the heart – the blood is at a higher pressure here because it has just been pumped. Arteries branch into arterioles (smaller arteries).
Veins carry blood back to the heart to be pumped elsewhere. These vessels are similar in size to the arteries, but they only have a small amount of muscle in their walls. To avoid any blood going backwards due to a lack of pressure, veins have one-way valves in them.
Capillaries (see Figure 2.33) are the thinnest of the blood vessels: their walls are only one cell thick to allow substances to easily pass in and out of the blood. Capillaries are the vessels connecting the arteries and veins.

Question 19

The Lungs

Answer 19

There are two lungs in our chest, which change in size every time we take a breath and they fill with air. The trachea branches into two to carry air into each lung. These branches are called bronchi. The lungs feel spongy to touch because they are home to millions of tiny air sacs called alveoli (see Figure 2.36 on page 84). If these air sacs were unravelled and flattened, they would have a surface area of approximately half the size of a tennis court. Each tiny alveolus

Question 20

The Diaphram

Answer 20

The diaphragm is a dome-shaped muscle that is attached to your ribs and moves
up and down beneath your lungs. The muscle contracts down and relaxes up. The diaphragm also separates the heart and lungs from the stomach and digestive system. The lungs have no muscle tissue, so they can’t move on their own. Muscles between the ribs lift the rib cage up and out to increase the ‘suction’ of air into the lungs.

Question 21

Comparing Respiration With Breathing

Answer 21

The reaction that occurs in human body cells to produce energy is the same reaction we saw in plant cells: respiration. Oxygen taken in by the lungs reacts with glucose, which the digestive system releases from the food we eat.
glucose + oxygen → carbon dioxide + water + energy C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
The energy produced by respiration is then used for all the jobs the cell needs to perform, from making and breaking down substances to making new cells. You can see why people get confused about the difference between breathing and respiration – respiration is the actual process that happens in cells and breathing is the inhalation of oxygen and exhalation of carbon dioxide by your lungs and other organs in the respiratory system.

Question 22

The Kidneys

Answer 22

You have two kidneys, one on each side of your lower back. They are approximately 10 centimetres long. Blood carrying waste products enters your kidneys to be filtered by tiny structures in the kidney called nephrons. At the end of this filtering process there are two main outputs: clean blood in the renal vein and urine in the ureter.
The kidneys are also responsible for regulating the levels of water and salts in the blood. This can affect blood volume and pressure. If you drink large quantities of water, you will produce a larger volume of pale-coloured urine than if you do not drink much water. Urine is stored in the bladder before it passes down the urethra to be expelled from the body.

Question 23

The Skin

Answer 23

The
skin plays a very important role in releasing waste heat by evaporation of sweat from wet skin. If you have ever licked your upper lip after exercise, you will know that your sweat is also very salty. This is because some salt is also excreted through the skin.

Question 24

The Liver

Answer 24

All our food has to be metabolised, or processed. Metabolism is the name given
to the chemical reactions that occur in
the body. These reactions can break down substances or build new substances. The liver is responsible for the metabolism of many substances, especially waste substances. Waste substances that can be dangerous
to the body are often changed into less dangerous forms by the liver before their removal from the body.

Question 25

What is Waste?

Answer 25

Our bodies produce a number of substances that need to be removed to avoid damage
to our bodies. The human body, like all organisms, relies on a careful balance of inputs and outputs to work properly. Some substances are just taking up precious space, whereas others can actually harm us. Water is important in controlling wastes because it can dilute harmful substances, reducing the damage they can cause at the same time. Water also helps move substances quickly and is essential for keeping our body temperature just right.
When your body digests proteins, it breaks them down into smaller molecules called amino acids. Your liver converts
these amino acids into glucose for energy. During this process, a very toxic substance called ammonia is produced. The liver then uses energy to change the ammonia into a safer substance called urea, which is then filtered by the kidneys for removal. When you have not drunk much water, you will have noticed that your urine is darker and smells more strongly. When you have drunk enough water your urine is lighter and has no smell. The amount of water in your urine can dilute the colour and smell of urea. Storage of the faeces in the rectum and their expulsion through the anus is not
considered part of the excretory processes. The contents of the josh suncdzncuksdncihdsnvkjxfhvkhfdbvhzbfdhjvbfdzhjvbadfihvfeabuivernyivfdniyvddzhyivfezbi tract are not really considered to be within the body until the digested food is absorbed into the blood in the intestines.
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Question 26

The Skeletal System

Answer 26

The skeletal system or skeleton in the adult human consists of 206 bones of varying shapes and sizes. It includes the bones that make up the skull and spine and the bones
of the limbs, shoulders and pelvis. It also consists of the three tiny bones that transfer vibrations in the ear to allow us to hear. The skeletal system includes the long bones found in our limbs that are levers for movement. The vertebrae provide support and flexibility, and the skull and ribs protect vital organs.
Bones are living tissues, which means they can repair themselves when damaged. They contain cells surrounded by calcium phosphate, the substance that makes the bone hard, and collagen, which provides elasticity. Blood vessels supply the bone with the nutrients it needs. The marrow inside bone is also very important because it is the site of production of blood cells.
Bones meet other bones at joints, which are the pivot points of the bone levers. Some joints are highly moveable because they are capsules containing membranes that secrete a type of lubricating liquid. Many bones are tipped by a tissue called cartilage, which cushions impacts with the joining bone and reduces friction.
Ligaments hold adjoining bones together in the joint. The shoulder and hip joints
are ball-and-socket joints, which allow movement in many directions. The elbow and knee are hinge joints, and they only move in one direction. Other types of freely moveable joints include pivot joints, which allow the head to turn on the spine, and gliding and saddle joints that allow movement in the wrist and ankle.

Question 27

The Muscular System

Answer 27

The muscular system consists of about 640 skeletal muscles that are responsible for movement and posture, smooth muscles and cardiac muscle.
A muscle is made up of muscle fibres containing protein molecules that slide over one another to bring about muscle shortening or contraction. Muscle fibres are bundled together and the end of the muscle, the connective tissue from the bundles, combines to form tendons that attach to the skeleton. Skeletal muscles attach to bones of the skeleton to bring about voluntary movement.