Nt1310 Unit 9 Lab Report

There are several organ systems involved with performing or assisting with the action of typing. The integumentary system acts as a barrier to protect the fingers from harm or pathogenic agents from the keyboard. Thick skin, such as the skin of palms, has five skin layers including the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum, in order to protect the fingers from wear and tear. The integumentary system also provides protection with chemical barriers such as the acid mantle, which retards bacterial growth; human defensin, which kills bacteria; and cathelicidins, which prevent infections. Biological barriers in the epidermis such as Langerhans cells, tissue macrophages that act as antigen presenting cells, are also present. The integumentary system is also responsible for cutaneous sensation by sending signals received from Merkel cells in the epidermis and Meissner’s corpuscles in the dermis to the brain via nerves.

The purpose of this lab was to determine which regions of the body have the most touch receptors and in turn which regions of the body have the greatest representation on the somatosensory cortex map. The somatosensory cortex map is located in the parietal lobe and processes tactile information (D. Purves, Augustine, & Fitzpatrick, 2001). According to Neuroscience 2nd edition, the increased representation of specific body areas in somatosensory cortex map is a function of evolution (D. Purves, Augustine, & Fitzpatrick, 2001). To determine the regions of the body with the greatest representation on the somatosensory cortex map a two point discrimination test was selected. This test has been used to measure tactile spatial acuity

The afferent division, picks up sensory stimuli; telling the brain that something is happening to your body. When the hot spoon touches your arm, the sensory division sends a message through the PNS to the brain saying that’s what’s happening.

The average 2 point threshold of the fingertip is 3mm, making it the most sensitive body part tested. There are more sensory neurons in the fingertip than in other parts of the body, which means there is a larger part of the brain that receives and analyzes their signals (Yuhas 2012). “Hairy skin has fewer endings and different kinds, and so produces a different sensory experience; skin

Dorsal-column-medial-lemniscal and spinothalamic pathways control different sensations. The dorsal column-medial lemniscal pathway controls mostly touch, vibration, and pressure on the skin. The spinothalamic pathway is in charge of pain, temperature, and touch. The dorsal-column-medial-lemniscal starts with the dorsal root axon and end with synapses in the thalamus and finally the cerebral cortex. The spinothalamic pathway begins with the dorsal root axon, and then the axon travels contra laterally through the spinothalamic tract and reaches the thalamus and synapses with the axon in the thalamus and sends signals to the cerebral cortex as well.

The cerebral cortex in the forebrain has special senses and general senses (Saladin, 2011). Some of these senses include smell, hearing, equilibrium, vision, touch, pressure, temperature, and pain. These all deal with sensory awareness and motor control. (Saladin, 2011).

Then I answered the touch part of the challenge. At first, I believed the mouth has many more touch receptors than one’s hand does. However, I was proved incorrect by this test. Apparently, one’s fingertips have more sensitive touch receptors than many other parts of your body. These touch receptors react to pressure, and they are responsible for telling you when your plate is hot when you take it out of the microwave, or the feeling you get when you touch a cold window during the winter.

Unlike the other senses that have localized areas of reception, such as the eyes or the nose, the varied receptors for touch are found throughout the entire body. Although, most are found in the living layers of the skin, otherwise known as the dermis, the receptors are found throughout the entire body. (Kandel) Due to the spread of these receptors, in order to save space and conserve resources, there are many receptors that have synapses, which are similar to electrical relays, to the brain that have been grouped together. (Kandel) Referring to the synapses as grouped, means that each neuron in a specific area sends its electrochemical signal to a single neuron before the signal goes to the brain. (Kandel) This means that in any given area

How information from outside world will be transformed to the brain? Receptors act as interface between external world and the brain. One type of receptors used in our bodies is tactile receptors. Tactile receptors have stretch-gated ions that will open by deformation of the skin and cause generation of a signal (tactile receptor activation). Receptors are located in receptive fields that are defined as an area to which a neuron responds. Skin has four types of tactile mechanoreceptors: Merkel Cells (Corpuscle), Meisnner’s corpuscle, Pacinian corpuscle, Ruffini corpuscle. Receptors are innervated by afferents. There are four types of mechanoreceptive afferent: Slowly Adapting Type-I, SAI (Merkel cell, static indentation), Slowly Adapting

pressure, contact and pain. Sensation is detected through the nerve endings in the dermis which

The human body may not be equally receptive to touch, and sensitivity appears to vary from one part of the body to the other. The purpose of this lab is to determine which part of the body is the most sensitive in distinguishing separate pressure points. The skin which is thought to be more sensitive will recognize separate pressure points at a shorter distance. Skin unable to make out separate pressure points until a larger distance, is thought to be less sensitive. The sites of the body which will be tested are the face, back of neck, back of hand, palm of hand, and fingertip. If the fingertip is the most sensitive, then the fingertip will have the least two-point threshold. “Human fingers can identify textures whose ridges

More importantly, Newton discovered sensory mechanisms in insects that could mirror the sensory systems of humans. It is now known that aspects of human mechanoreceptors are similar to the receptors that Newton investigated. Humans have mechanoreceptors that adapt rapidly to stimuli (Meissners and Pacinian corpuscles) similar to the high threshold afferent hairs that Newton examined. Additionally, humans have slowly adapting mechanoreceptors (Merkels disks and Ruffinis endings) like the low threshold afferent hairs that Newton

The process of imparting and interplaying information with the suroundings is done by somatosensory system1.Many pursuits of daily life requires its functioning. Sherrington classified sensory system into:Exteroceptive sensation (superficial sensation):tactile sensation (thigmesthesia), Pain sensation (algesia), Temperature sensation (thermesthesia), Vibratory sensation (pallesthesia).Proprioceptive sensation (deep sensation):Joint position sense (arthresthesia),Kinesthesia: motion sense.Cortical sensations:Stereognosis: ability to recognize and identify objects,Graphesthesia: ability to recognize symbols written on the skin,Two-point discrimination: ability to recognize simultaneous stimulation by two blunt points,Touch localization

Introduction: sensory biology focuses on the sensory system consisting of sensory receptors that receives stimuli from internal and external environments, neural pathways conduct this information to the brain and parts of brain that processes this information. The information is called sensory information and it may or may not lead to conscious awareness. If it does, it can be called sensation. The purpose of this experiment was to conduct some experiments and observe the properties of sensory biology in the human body. Campbell, Reece; 2008; Biology text; eighth edition