The Nervous System and Endocrine Systems Flashcards
action potential
A neural impulse. A brief electrical charge that travels down an axon when it fires.
adrenal glands
Small glands that produce steroid hormones, adrenaline, and noradrenaline, which help control heart rate, blood pressure, and other important bodily functions. There are two adrenal glands, one located on top of each kidney.
all-or-none law
This law states that the process by which a neuron fires is all or none. Either a neuron receives sufficient stimulation from surrounding cells to fire, or it doesn’t. There is no variation in the size of the electrical impulse once the neuron fires.
amygdala
A portion of the limbic system of the brain that is linked to emotions and forming long-term memories.
applied research
Research that is conducted to solve a specific or practical problem.
association areas
Portions of the cerebral cortex that integrate material from many parts of the brain. These areas are responsible for higher brain functions such as remembering, learning, and interpreting sensory information.
autonomic nervous system
The portion of the nervous system that controls glands and muscles of the internal organs.
axon
A long, hair-like extension of a nerve cell (a neuron) that transmits electrical impulses away from the cell body.
blood-brain barrier
The protective barrier, composed of glia, that keeps certain substances in the blood from reaching brain tissue.
brain stem
The portion of the brain that connects the upper brain with the spinal cord. The brain stem is responsible for life-sustaining functions such as heartbeat and respiration, as well as maintaining alertness.
CAT (Computerized Axial Tomography)
A computerized series of X-rays taken from different angles that are compiled to create an image of the area in question.
central fissure
A long, deep fissure on the lateral surface of the cerebral cortex.
central nervous system
The portion of the nervous system consisting of the brain and spinal cord.
cerebellum
The portion of the hindbrain that helps to control posture, balance, and motor coordination.
cerebral cortex
The outer layer of nerve cells covering the cerebrum that is responsible for most higher cognitive functions.
cerebral hemispheres
The right and left halves of the cerebrum.
chromosomes
Structures made of deoxyribonucleic acid (DNA) that contain genes. Chromosomes are located in the nucleus of a cell. Humans normally have 23 pairs of chromosomes, or a total of 46.
corpus callosum
The bundle of nerve fibers that connects the left and right hemispheres of the brain.
dendrites
The bushy ends of a neuron that pick up information from neighboring cells and transmit it to the cell body.
depolarize
To make the cell membrane charge less negative. If the cell membrane is sufficiently depolarized, the neuron will fire.
DNA (deoxyribonucleic acid)
The substance inside a cell’s nucleus that contains instructions for all of the structures and processes that the body needs to function.
electrochemical
A process that is both electrical and chemical. Neuron transmission is electrochemical because there is an electrical process within the neuron, but there is a chemical process that takes place in the synapse, or the gap between neurons.
endocrine system
A system of glands that release hormones into the blood.
endorphins
Substances produced by the body that are involved in pain relief and positive mood.
epinephrine
A hormone secreted by the adrenal medulla that is stimulated by the central nervous system in response to stress or fear. It acts to increase heart rate, blood pressure, cardiac output, and carbohydrate metabolism.
excitatory
A substance that increases the likelihood a neuron will fire.
forebrain
The largest and most recently evolved division of the brain. It contains the cerebral cortex, the basal ganglia, the thalamus, and the hypothalamus.
GABA
The main inhibitory receptor in the central nervous system.
glial cells
Cells that surround neurons, providing support and insulation.
hemisphere
The left or right half of the brain
hindbrain
The hindbrain is the portion of the brain that is responsible for many basic life-support functions such as the coordination of motor activity, posture, equilibrium, and sleep patterns. It also helps regulate breathing and blood circulation.
hippocampus
A portion of the brain located inside the temporal lobes. It is part of the limbic system and is involved in learning and formation of long-term memories.
hormone
A substance that is released by the endocrine glands and travels through the blood to influence other glands and organs.