Showing posts with label sensory system. Show all posts
Showing posts with label sensory system. Show all posts

Wednesday, 4 May 2016

The Brain





The Brain:


Image result for the brain






Functions of the brain:

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 brain that 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.



    Wednesday, 27 January 2016

    Link-up Summary: Sound

    Sound is a form of energy caused by vibrations. 

    Click on the picture to see the animation.


    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?

    desk

    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.

    Click on the picture to see the animation

    And finally...

    How do we know that sound is a form of energy?


    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.