Objectives
· Describe how sensory receptors communicate to the central nervous system.
· Describe receptors that detect temperature, pain, touch and pressure, muscle length and tension, and blood pressure.
· Describe the nature of vision in terms of its stimulus on the function of rod and cone cells.
Introduction
The function of the brain is to convey messages to different parts of the body. Messages are conveyed from a nerve cell to another nerve cell, muscle cell, or a gland. The messages are in the form of electrical signals called neurotransmitters. Neurotransmitters are chemicals that are released from a nerve cell that relay a message. Examples of neurotransmitters are acetylcholine, norepinephrine, …show more content…
The resting potential of a nerve cell is approximately -70 mV (millivolts). When a neurotransmitter triggers an action potential, sodium voltage gated channels open and allow sodium (positively charged) to diffuse into the cell. The diffusion of sodium causes the inside of the cell to obtain a positive charge. When the inside of the cell reaches +30 mV, the sodium voltage gated channels close preventing any additional sodium to diffuse into the cell. Next, the potassium voltage gated channels open and enable potassium to diffuse out of the cell.
This allows the inside of the cell to return to its original negative charge.
Laboratory Activities
Exercise 1: Understanding the Human Brain
You have been entrusted with the care and feeding of the most extraordinary and complex creation in the universe. Home to your mind and personality, your brain houses your cherished memories and future hopes. It orchestrates the symphony of consciousness that gives you purpose and passion, motion and emotion.
Go to, http://www.alz.org/alzheimers_disease_4719.asp, which is sponsored by the Alzheimer’s Association and take a tour of the brain. Click on “Start Tour”.
Questions: Understanding the Brain
1. What is the texture of the brain?
Texture similar to firm