Emer has researched and prepared another informative article about ....TEETH! Well done Emer! The teeth help to prepare food for digestion by cutting and grinding it up. Each tooth is set into the jaw, which has a soft tissue covering called gum. During our lives we have two sets of teeth baby teeth (20) and later permanent teeth (32).
Parts of a tooth;
Enamel:A substance similar to the bone, though it is harder (the hardest substance in the body) and has no living cells. It consists of tightly-packed crystals of apatite, a mineral which contains calcium, phosphorus and fluorine. Dentin: A yellow substance which forms the second layer inside a tooth. It is not as enamel but, like it, has many of the same constituents as bone. It also contains collagen fibres and strands of cytoplasm. These run out from the pulp cells in the pulp cavity. Cervix: The part of a tooth just below the surface, lying between the crown and the root. Enamel: A substance similar to bone, through it is harder and has no living cells. It consists of tightly- packed crystals of apatite, a mineral which contains calcium, phosphorus and fluorine. Cement: A bone- like substance, similar to enamel but softer. It forms the thin surface layer of the root and is attached to the jaw by the periodontal ligament. Pulp cavity: The central area of the tooth, surrounded by dentin. It is filled with a soft tissue called pulp, which contains blood vessels and nerve fibre endings. These enter at the base of a root canal. The blood vessels supply food and oxygen to the living tissue, and the nerve fibre endings are pain receptors.
Different types of teeth and their functions:
Wisdom teeth: Four molars ( the third ones in line), lying at the end points of the jaws. They appear last of all, when a person is fully mature. Often there is no room for them to come through and they get stuck in the jawbone, or impacted. A few people never develop wisdom teeth.
Sources: The Usborne Illustrated Dictionary of Science
FRONTAL LOBES: You use your frontal lobe nearly everyday. You use it to make decisions, such as what to eat or drink for breakfast in the morning, as well as for thinking or studying for a test. The frontal lobe is also where our personality is formed and where we can carry out higher mental processes such as planning. In addition, the frontal lobe is necessary to being able to speak fluently (without fault) and meaningfully.
PARIETAL LOBES: The parietal lobe carries out some very specific functions. As a part of the cortex, it has a lot of responsibilities and has to be able to process sensory information within seconds. The parietal lobe is where information such as taste, temperature and touch are processed. Humans would not be able to to feel sensations of touch, if the parietal lobe was damaged.
OCCIPITAL LOBES: The occipital lobe is important to being able to correctly understand what your eyes are seeing. These lobes have to be very fast to process the rapid information that our eyes are sending. Similar to how the temporal lobe makes sense of auditory information, the occipital lobe makes sense of visual information so that we are able to understand it. If our occipital lobe was impaired or injured we would not be able to correctly process visual signals, therefore, visual confusion would result.
TEMPORAL LOBES: The temporal lobe mainly revolves around hearing and selective listening. It receives sensory information such as sounds and speech from the ears. It is also key to being able to understand speech. In fact, we would not be able to understand someone talking to us, if it wasn't for the temporal lobe. This lobe is special because it makes sense of the all the different sounds and pitches(different types of sound) being transmitted from the sensory receptors of the ears.
CEREBELLUM: The cerebellum is one of the most identifiable parts of the brain due to its unique shape and location. It is extremely important for being able to perform everyday voluntary(done with purpose and intent) tasks such as walking and writing. It is also essential to being able to stay balanced and upright. Patients who have suffered from damaged cerebellums often struggle with keeping their balance and maintaining proper muscle coordination.
BRAIN STEM: The brainstem is the region of the brain that connects the cerebellum with the spinal cord. It consists of the midbrain*, medulla oblongata*, and the pons*. Motor and sensory neurons* travel through the brainstem allowing for the relay of signals between the brain and the spinal cord. Most cranial nerves* are also located in the brainstem.
The brainstem coordinates motor control signals sent from the brain to the body. This brain region also controls life supporting autonomic functions of the peripheral nervous system*. The fourth cerebral ventricle* is located in the brainstem, posterior to the pons and medulla oblongata. This cerebrospinal fluid-filled ventricle is continuous with the cerebral aqueduct and the central canal of the spinal cord*.
Function
The brainstem controls several important functions of the body including:
Alertness
Breathing
Blood Pressure
Digestion
Heart Rate
Relays information between the Peripheral Nerves and Spinal Cord to the upper parts of the brain
~KEYWORDS~ *Midbrain*- A small central part of the brainstem, developing from the middle of the brain. *Medulla oblongata*- The continuation of the spinal cord within the skull, forming the lowest part of the brainstem and containing control centres for the heart and lungs. *Pons*- The part of the brainstem that links the medulla oblongata and the thalamus.
*Sensory Neurons*- Sensory neurons are nerve cells that transmit sensory information (sight, sound, feeling, etc.). They are activated by sensory input, and send projections to other elements of the nervous system, transfering sensory information to the brain or spinal cord. *Cranial Nerves*- The cranial nerves are twelve pairs of nerves that can be found at the bottom surface of the brain. Some of these nerves bring information from the sensory organs to the brain, some can control muscles, and some are connected to glands or internal organs such as the heart and lungs.
*Peripheral Nervous System*- This is the nervous system outside the brain and spinal cord. *Cerebral Ventricle*- It is one of a system of four communicating cavities (ventricles) within the brainthat are continuous with the central canal of the spinal cord. *Spinal Cord*- The cylinder shaped bundle of nerve fibres and associated tissue which is enclosed in the spine and connects nearly all parts of the body to the brain, it forms the central nervous system.
First years are revising for the summer tests and making mind maps.
Well done Olivia and Ben for making these posters! They are detailed, colourful and very well laid out!
Abby has done some great work researching the eye... well done Abby!
The Eye:
The eye is a very important part of the body it lets us see things. The eye consists of many different parts, Each of these parts has a different function:
Different parts of the eye:
SCLERA- This is the opaque layer on the outside of the eye, its function is to protect the eye.
CORNEA- This part of the eye acts like a window, it controls and focuses the amount of light allowed into the eye.
PUPIL- This is the part of the eye which light passes through.
LENS- This is the part that lets us see shapes as they are and at different distances, it allows the real image to be formed at the retina.
IRIS- This is the coloured part of the eye, it helps control the amount of light entering the eye. when the light is bright, this part of the eye closes the pupil to let in less light and when there is low light this part of the eye opens the pupil to let in more light.
CILIARY BODY- This part of the eye realeases a clear liquid called aqueous humor, it also changes the shape of the lens when your eye focuses on something.
CHOROID- This part of the eye looks mainly at helping the outer layers of the retina, it also controls heat and pressure, whilst absorbing excess light to try and avoid reflection.
RETINA- This part of the eye is a light-sensitive layer at the back of the eye, it converts light energy that reaches it into signals which are then sent to the brain by the optic nevre.
FOVEA CENTRALIS-This part of the eye is tiny but responsible for providing us with our most clearest, sharpest vision, by having a healthy fovea, it is the key to reading, watching T.V, driving and other activities that need to see things in detail. this part of the eye has no blood vessels.
OPTIC NERVE- This part of the eye transfers visual images (what we see) to the brain from the retina through electrical impulses, it is made up of nerve cells.
SUSPENSORY LIGAMENT- This is the part that supports the eye, it forms a hammock beneath the eyeball for this support.
BLOOD VESSELS- These are capillaries and arteries throughout the eye.
OPTIC DISC (BLIND SPOT)- This is the part of the eye where the *ganglion cell axons* leave the eye, because there is nothing overlying this, it results in a blind spot in each eye.
The Optic Nerve (Blind Spot):
To find your blind spot here is a quick experiment:
- Put your right hand over your right eye, and stare at the black dot.
- Move closer or further away, and you will find you can't see the ➕ anymore, this is because that is your blind spot!
Well done to my first year science class who did some amazing work over the holidays to produce these posters for Wellbeing Week. The idea was to create a poster which showed the negative effects that smoking can have on your health, and focusing on the lungs as we have been studying breathing. Here are a few of my favourite posters!
By Saoirse Flanagan Have you ever noticed that you may feel slightly happier after eating chocolate? The ‘feel-good-feelings’ one experiences after eating chocolate is not just because it tastes good, it’s a result of the 300+ naturally-occurring chemicals it contains!
One of these chemicals is called anandamide, which is also found naturally in the brain. Anandamide causes the production of dopamine.The results of this chemical on the brain can be described as a blissful feeling or ‘intense well-being’.
Phenylethylamine (a.k.a. The Love Drug) is a natural ‘upper’ found in chocolate which makes your heart pound a little faster. It produces a pleasant feeling and some say it’s the feeling of being in love!
Another reason chocolate makes us feel good is because it releases endorphins into the brain. Endorphins reduce our perception of pain, helps reduce anxiety and depression and, as a result, triggers a positive feeling in the body.
I suppose you can conclude that a little bit of chocolate wouldn’t do too muchharm!
Here are some of the videos I showed in class recently. I have included some additional videos to help you develop your understanding of the digestive system.
Ingestion
X-ray video of person swallowing coloured drink
Click on the picture to see the gif
Digestion
Enzymes
An enzyme is a biological catalyst.
made of protein
alters the rate of a chemical reaction without being used up in the reaction
This article was researched and written by David Oki. Well done David!
Blood is made up of watery plasma in which three types of cell are suspended: red blood cells, white blood cells and platelets.
This video shows how centrifugation (spinning a test tube of blood at high speeds) is used to separate blood into its components.
Plasma
Plasma is 90% water and contains dissolved substances such as glucose, amino acids, fatty acid, mineral, vitamins, carbon dioxide, urea, hormones, antibodies and large soluble protein.
Red blood cell
Biconcave discs, with no nucleus or mitochondria. They live for 120 days and are then broken down by the liver. They are made continuously in the red bone marrow of the sternum, ribs and vertebrae. They contain the red, iron-containing chemical haemoglobin which can combine with oxygen to form oxyhaemoglobin.
White blood cells
Larger and less numerous than red blood cells, they have a nucleus. They protect the body against disease. There are two types: monocytes and lymphocytes. Monocytes have a lobed nucleus and tiny granules in the cytoplasm. They engulf bacteria by phagocytosis.
Platelets
These are fragments of cells formed in the red bone marrow. They have an important role in clotting of the blood.
Sound is produced when particles vibrate.
A loudspeaker creates sound because is causes the air around it to vibrate in a pattern of waves that reaches your ear... see the animated version here.
The sound of your voice is produced when your vocal chords vibrate as air is passed over them.
Hearing
The ear is a sense organ which detects sound vibrations. Exposure to very loud sounds can cause damage to your hearing.
The outer ear collects the sound and channels it along the ear canal.
The middle ear (ear drum and tiny bones called hammer, anvil and stirrup) conducts the sound into the inner ear.
The inner ear converts the sound energy (vibrations) into an electrical signal which can be sent to the brain.
The auditory nerve is a sensory nerve which sends electrical signal to the brain.
This animation shows the structures in the ear very clearly.
Sound needs a medium to travel through
Because sound is transmitted through the vibration of particles, sound needs a medium to travel through, such as air or water.
A vacuum is a space that is completely empty of matter. There are no particles in a vacuum. Sound cannot travel through a vacuum.
This animation shows a bell inside a jar. When all the air is drawn out of the jar, and a vacuum is created, you can no longer hear the sound of the bell.
Because sound cannot travel through a vacuum, this means that sound cannot travel in outer space.
This article talks about sound at high frequencies... and how students can hear sounds that teachers probably cannot hear!
Speed of sound
Sound travels more quickly through materials that are more dense.
Check it out: tap your finger lightly on the desk. You probably hear a quiet sound. Now lay your ear on the desk and tap again. Can you hear a difference?
Sound can travel through the solid material of your desk more quickly than through the air.
Sound travels faster through liquids than it does through gases, such as air. So the speed of sound in water is 1500 metres per second, while the speed of sound in air is only 340 metres per second.
Thunder and lightning
Thunder and lightning originate at the same moment. However you can often see the lightning before you hear the thunder. This is because light travels faster than sound. Learn how to calculate how far away you are from the storm here.
Echoes
Echoes are reflected sound.
Ships use echolocation to measure the depth of the sea below them.
Fishing boats can also use echolocation to detect shoals of fish swimming beneath the boat.
Remember that sound is a form of energy, caused by vibrations. Here is a video of an Irish physics teacher demonstrating that sound is a form of energy. Energy is the ability to do work or to move something. The sound energy from the speaker causes the flame of the candle to move.
Knowledge check:
OP40 Show that sound is a form of energy, and explain
that sound is produced by vibrations
OP41 Show that sound transmission requires a medium
and that echoes are reflected sound
OP42 Appreciate that the ear
detects sound vibrations and that exposure to very loud sounds can cause damage
to hearing
OP43 Recall that the speed of sound is less than the
speed of light
OP44 Explain the time lag between seeing and
hearing the same event
Post compiled by Ms McCarthy. The website thephysicsteacher.ie contains many helpful links which I have used in this blogpost.
