Brain and Mind Behavior
1.
i.
Types of Receptors Functions Receptive Fields Response
Merkel’s Discs Touch, pressure and texture Fingertips, tongue, lips, located in dermis Responds to change in stimuli
Meissner’s Corpuscle Touch sensitivity Located in the dermis Responds to change in stimuli
Pacinian Corpuscle Vibration and pressure Located in the hypodermis Responds to change in stimuli
Ruffini’s endings Stretching Located in the hypodermis Responds to change in stimuli
ii.
Primary somatosensory cortex-
• Located in parietal lobe of brain
• Nerve signals of the sense of touch are received
• The more sensitive the region, the more it takes up in the somatosensory
Secondary somatosensory cortex-
• Located in lower parietal lobe of brain
• Maps the overlapping area of both sides of human body
• Receives information from the primary somatosensory cortex
Pain--- travels through the spinal cord---synapses between spinal cord and neuron ---into medulla---parietal lobe
Touch---travels through spinal cord---into medulla---left side functions of the body is controlled by the right side of the brain and the right side of the body is controlled by the left side of the brain.
iii.
Pain Receptors-
• Located on any nerve endings in the body (i.e. skin, muscles, joints, organs, etc.)
• C fibers are afferent nerves which means they send signals to the spinal cord and brain
• C fibers are thin and unmyelinated
• Alpha fibers are thicker and myelinated which allows quicker connection with spinal cord(i.e. direct contact with a hot stove. We feel it instantly)
• Spinothalamic system- sends pain from our bodies to our brains in order for it to register
Ascending-
Skin--- spinal cord--- medulla--- spinothalamic path--- mid brain---parietal cortex/reticulothalamic tract--- midbrain---cingulate cortex
Descending-
Skin---spinal cord---medulla ---midbrain---hypothalamus/ frontal cortex
2.
i.
1. Sound wave enters pinna (visible part of ear).
2. Travels through middle ear by the use of 3 bones (incus, stapes, and malleus).
3. In the middle ear the sound is amplified in order to move the fluid in the ear.
4. In the inner ear (cochlea) the sound is converted into neural activity.
Basilar membrane acts as a divider of two fluids (scala media and the scala tympani) and the hair cells pick up movement in order to send a signal to the brain to interpret the sound.
ii.
The organ of corti is an extremely sensitive area of the cochlea. It transforms pressure waves into action potentials
iii.
After the sound is processed in the cochlea, the auditory information travels into the brain in order to be interpreted.
3.
i. Retina-
• Photoreceptors- detects light
• Bipolar Cells- transmit signals from the photoreceptor to the ganglion cells
• Ganglion Cells- carry information given by bipolar cells to the brain to register
• Horizontal Cells- help us adjusting our eyes to brighter or dimmer lights
• Amacrine Cells- inputs a large portion of ganglion cells
Hearing allows us to take in noises from the surrounding environment and gives us a sense of where things are in relation to us. All those little folds on the outside of the ear, called the tonotopic organization, make it so sound waves in the air are directed to the ear canal, where they can be further processed. Once in the ear, the sound waves vibrate the ear drum, which tell the ear exactly what frequency it is sensing. The vibration of the ear drum is not quite enough to send a signal to the brain, so it needs to be amplified, which is where the three tiny bones in the ear come into play. The malleus or hammer, incus or anvil, and stapes or stirrup amplify this sound and send it to the cochlea. The cochlea conducts the sound signal through a fluid with a higher inertia than air, so this is why the signal from the ear drum needs to be amplified. It is much harder to move the fluid than it is to move the air. The cochlea basically takes these physical vibrations and turns them into electrical impulses that can be sent to the brain. This is...
Cochlear implants are electronic devices that sends signals directly to the auditory nerve. Cochlear implants consist of external parts which include the microphone, speech processor, and the transmitter. They also consist of internal parts that must be surgically placed under the skin including the receiver and electrical array. In order for the implant to work, the microphone
Sound is localised to the ear by the pinna, travelling down the auditory canal, vibrating the eardrum. The eardrums vibrations are then passed down through the ossicles, three small bones known as the hammer, anvil and stirrup that then transfer the vibrations to the oval window of the cochlea. The cochlea is filled with fluid that when exposed to these vibrations stimulate the sterocilia. This small hair cells "wiggle" along to certain frequencies transferring the vibrations into electrical impulses that are then sent to the brain. If the ear is exposed to noise levels of too high an intensity the sterocilia are overstimulated and many become permanently damaged . (Sliwinska-Kowalska et. All,
This reduces the amount of current that would otherwise leak out of the axon and increases the distance that the current can flow passively. Myelination, aka axon insulation, increases action potential conduction up to 150m/s compared to 0.5-10m/s conduction velocities of unmyelinated axons! Speedy delivery of current information along axons is also due to the nodes of Ranvier. Nodes of Ranvier are gaps between insulated portions of the axon. The gaps create a place where the current can flow out of the axon so an action potential can be generated.
Let’s say that there is a mechanical sense. If someone touched your hand, your somatosensory system will detect various stimuli by your skin’s sensory receptors. The sensory information is then conveyed to the central nervous system by afferent neurons. The neuron’s dendrites will pass that information to the cell body, and on to its axon. From there it is passed onto the spinal cord or the brainstem. The neuron's ascending axons will cross to the opposite side either in the spinal cord or in the brainstem. The axons then terminates in the thalamus, and on into the Brodmann Area of the parietal lobe of the brain to process.
From this point, vibration of the connective membrane (oval window) transforms mechanical motion into a pressure wave in fluid. This pressure wave enters and hence passes vibrations into the fluid filled structure called the cochlea. The cochlea contains two membranes and between these two membranes, are specialized neurons or receptors called hair cells. Once vibrations enter the cochlea, they cause the lower membrane (basilar membrane) to move in respect to the upper membrane (i.e. the tectorial membrane in which the hair cells are embedded). This movement bends the hair cells to cause receptor potentials in these cells which in turn cause the release of transmitter onto the neurons of the auditory nerve.
serves as a channel for the sound to go into. The sound that you hear travels in vibrations. Those vibrations make the eardrum start to vibrate. When the eardrum starts to vibrate it makes three small bones bump into each other and a signal is sent to the inner ear. The signal is then sent to the cochlea, which is the Greek word for snail. In the cochlea there is a fluid, and from all the vibrations it pushes the fluid through the coil. This then activates the receptor cells or the hair cells to send a signal to the brain.
nerve processes that can branch out to send signals to various areas. Dendrites however usually
First let’s look at what happens when you hear music. Here is a diagram that shows and explains what happens when you listen to music. Outer ea...
...the auditory nerve to the brain. The sound has to travel through auditory nerves in order to reach the brain.
The ear houses some of the most sensitive organs in the body. The physics of sound is well understood, while the mechanics of how the inner ear translates sound waves into neurotransmitters that then communicate to the brain is still incomplete. Because the vestibular labyrinth and the auditory structure are formed very early in the development of the fetus and the fluid pressure contained within both of them is mutually dependant, a disorder in one of the two reciprocating structures affects the (2).
We hear sound because circulating conflicts cause the eardrum to vibrate, and feelings are transferred to the acoustic nerve through the fluid and bones of the ear. For example loudness is a relative term. One sound decreases source. As the sound is propagated outward, it is “spread” over a greater area. The minimum sound intensity that can be detected by the human ear...
The ear has three basic functions. The first is the most obvious, the filtration and analysis of sound by a part of the ear called the cochlea. This function consists of two parts: hearing and listening. Hearing is a passive process and we have limited abilities to improve it. Listening, ho...
The ear is an organ of the body that is used for hearing and balance. It is connected to the brain by the auditory nerve and is composed of three divisions, the external ear, the middle ear, and the inner ear. The greater part of which is enclosed within the temporal bone.
Then, when I was three years old, I had surgery to get a cochlear implant at the University of Minnesota. A cochlear implant is a small device which bypasses the damaged parts of the ear and directly stimulates the auditory nerve. Signals generated by the implant are sent by the auditory nerve to the brain, which recognizes t...