Download 3.4 PSYCHOACTIVE DRUGS AND HOMEOSTASIS

3.4 PSYCHOACTIVE DRUGS AND HOMEOSTASIS
SECTION 3.4 QUESTIONS
(Page 182)
Understanding Concepts
1. Stimulants increase heart rate and breathing rate. Depressants decrease heart rate and breathing rate.
2. A nerve cell transmits an impulse by releasing neurotransmitter molecules from vesicles in its terminal knobs.
The
impulse is transmitted when the neurotransmitter molecules attach to receptors in neighbouring cell membranes.
Some
depressants delay the effects of neurotransmitters, slowing down the transmission of impulses. Some stimulants
prevent the breakdown of neurotransmitter molecules. The neurotransmitters remain on receptors longer, resulting
in
more frequent impulses.
3. Short-term effects include slower heart rate, slower breathing rate, and increased urine output. Cirrhosis, an
accumulation
of fats in the liver that impair liver function, is a potential long-term effect. The fat build up means that the liver
can no longer eliminate waste or produce proteins, affecting all other organ systems.
4. In addiction, nerve cells in the brain adjust to long-term exposure to a drug by producing fewer neurotransmitter
receptor molecules. This causes neurons to become less sensitive to the drug.
5. Exercising normally increases heart rate and breathing rate in order to deliver more nutrients and oxygen to the
muscles of the body. After exercising, the body adjusts by slowing down breathing rate and heart rate to reestablish
homeostasis. Using a stimulant before exercising may prevent the body from re-establishing homeostasis.
Prolonged
high blood pressure, muscle tension, and fast heart rate may negatively affect the health of an individual.
Making Connections
6. Knowing how stimulants and depressants negatively affect homeostasis and health may cause a person to refrain
from
using these types of drugs.