Question

a. List the differences (in a table form) between sympathetic and parasympathetic arms of autonomic nervous system. b. Explain how sensory information is conveyed. (You could use a flow diagram to explain.)

Answer 1

a. Differences between sympathetic and parasympathetic arms of autonomic nervous system

Sympathetic	Prasympathetic
Sympathetic arm is involved in the fight or flight response.	Parasympathetic arm is involved in homeostasis, rest and digest response.
It prepares body for any potential danger.	It aims to brings back or restores the body to calm state.
Shorter neuron pathway, faster response time.	Longer neuronal pathway hence slower response.
Increases heartbeat	Reduces heartbeat
Muscles tense up	Muscles are in related state.
Pupils dilate and lets more light in	Pupils contracts permitting only few light.
Salivary secretion is inhibited	Salivary secretion is induced and hence digestion increases.
During fight, flight situations adrenaline is released.	No fight, flight response hence adrenaline is not released. Instead acetycholine is released.

b. The brain distinguishes sensory stimuli through a sensory pathway: action potentials from sensory receptors travel along neurons that are dedicated to a particular stimulus. The following flow chart shows the events that occur during the conveyal of sensory information to the brain

  

Reception 1 Transduction k Encoding Transmission Perception)

Reception is the activation of sensory receptors by any of the follwing stimuli such as mechanical stimuli, temperature, chemicals, etc. The receptor then responds to the stimuli received.

Transduction is the conversion or translation of sensory signal into electrical signal which takes place at the sensory receptor.

Encoding and Transmission of sensory information

There are several aspects of sensory information that are encoded by sensory systems: the type of stimulus, the location of the stimulus in the receptive field, the duration of the stimulus, and the relative intensity of the stimulus. Thus, action potentials transmitted over a sensory receptor’s afferent axons encodes what type of stimulus it is, and this segregation of the senses is preserved in other sensory circuits. The intensity of a stimulus is encoded by the rate of action potentials produced by the sensory receptor and number of sensory receptors activated.

Perception is an individual’s interpretation of a sensation. Although perception relies on the activation of sensory receptors, perception happens not at the level of the sensory receptor, but at higher levels in the nervous system, in the brain.