Biology: Nervous System Lab Report (Results and Discussions) (Lab Report Sample)

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Biology lab report
Abstract
Nervous system consists of brain, spinal cord and nerves connecting sensory organs. The brain and spinal cord receives signal from organs of peripheral nervous system and dictates course of action in responses to stimulus. The communications of central nervous system with peripheral organs is achieved through conduction of nerve impulses by cell known as neurons. This allows body to respond to various senses. Experiment conducted aimed at evaluating the rate at which one could process sensory information obtained visually, orally and tactually. It was found that rate at which an individual response to stimuli varies. This can be attributed to difference in sensitivity to stimulus.
Introduction
The nervous system controls voluntary and involuntary actions of an organism by ensuring proper communications between sensory and effector organs. It consists of central nervous systems which are the brain and spinal cord and all nerves in other body parts making peripheral nervous system. There are three types of neurons; sensory neurons conducts impulses from the sensory organs like skin to the central nervous system, motor neurons conduct impulse from central nervous system to the effectors while interneurons present in the brain and spinal cord act as a linkage between sensory and motor neurons. A neuron is organized into dendrites, cell body and axon. Axon may be myelinated as in motor and sensory neuron. Dendrite receives information and passes to the cell body. The message is carried by axon from cell body to synaptic knob to allow inter communication between two neurons or neuron and an effector cell.Therefore reflex arc is the communication between central nervous system and both sensory and effector organs. The sensory neurons take information to spinal cord and brain for interpretation.Motor neurons then relay information to effector tissues or organ for response. The sensory and motor neurons form part of peripheral nervous system.
Methodology
The five senses of sight, taste, touch and smell is perceived at different rates by different individuals. This formed basis for the experiment that was conducted to measure difference in the rate at which one could process sensory information obtained visually, orally and tactually. To validate hypothesis on visual difference, two individuals were chosen, a dropper and a catcher of a stick. The dropper of a stick held a meter rule vertically with 0 cm end in the waist level of a catcher whereas the 100 cm end was held high in the air. The catcher held her right’s hand with her thumb and forefinger with bottom of a meter rule. The catcher had to hold the meter rule tightly while the dropper prepared to drop the stick. The dropper dropped the stick without verbal cues and the catcher catches it quickly. The distance stick felled before catcher grabbed it was then measured. Experiment was repeated both with right and left hand while exchanging the roles between the two partners.
The experiment for auditory was repeated as for visual with some changes. The catcher had to close her eyes and was informed when the dropper was about to drop the stick by shouting "okay." The distance the stick felled was recorded for the two partners after switching their roles. The tactile experiment was carried out with catcher’s eyes closed. The dropper tapped the catcher on the shoulder to indicate she was about to drop the stick. The experiment was repeated for right and left hands for both partners and height recorded.
Results and discussions

Visual stimulus

Auditory stimulus

Tactile stimulus


Person1

Person2

Person1

Person2

Person1

Person2

Trial 1 L

20

18

8

16

14

15

Trial 1 R

12

17

12

5

12

10

Trail 2 L

18

18

7

18

14

10

Trial 2 R

11

13

14

9

10

13

The two persons responded differently to three stimuli. Person 1 responded quickly to visual stimuli using her left hand. Person 2 responded faster to visual stimuli with left hands for both trials. Auditory stimuli were generally low for both persons. This observation may be due to different rate of activation of neurotransmitters which stimulate response.
Message moving along nerve pathway usually takes time since it involves creation of action potential by exchanging Na and K ions across cell membrane of cell. It is then followed by release of transmitters through synaptic junction to stimulate response on effector cells such of organ such as muscle. Reflex process is automatic response toward stimuli. Example is leg stepping on a dangerous animal, leg initiate signal which goes to spinal cord. Relay neuron in spinal cord sends back message signaling leg to pull away from danger. Relay of information occur faster between the leg and spinal cord. The part of signal movement from leg to spinal cord and back to leg via nerves is called reflex arc.
The bundling of nervous tissue is similar to that of muscle tissue. The cells which behave as fiber are packed closely. Several muscle fibers are bundled together to form skeletal muscle which is surrounded by endomysium. Each bundle of musc...