Ch. 7.6 Nervous System Key Terms
Autonomic Nervous System
Contains the sympathetic and parasympathetic nervous systems, which work together to control involuntary body functions... It helps maintain a balance in the involuntary functions of the body and allows the body to react in times of emergency.
Cerebrum
The largest and highest section of the brain. The outer part is arranged in folds, called convolutions, and separated into lobes... responsible for reasoning, thought, memory, judgment, speech, sensation, sight, smell, hearing, and voluntary body movement.
Midbrain
The section located below the cerebrum at the top of the brainstem. It is responsible for conducting impulses between brain parts and for certain eye and auditory reflexes.
Peripheral Nervous System (PNS)
Consists of the nerves and has two divisions: the somatic nervous system and the autonomic nervous system.
Thalamus
Acts as a relay center and directs sensory impulses to the cerebrum. It also allows conscious recognition of pain and temperature.
Brain
A mass of nerve tissue well protected by membranes and the cranium, or skull.
Diencephalon
The section located between the cerebrum and midbrain. It contains two structures: the thalamus and hypothalamus.
Nerves
A combination of many nerve fibers located outside the brain and spinal cord.
Pons
The section located below the midbrain and in the brainstem. It is responsible for conducting messages to other parts of the brain; for certain reflex actions including chewing, tasting, and saliva production; and for assisting with respiration.
Ventricles
The brain has four hollow spaces that connect with each other and with the space under the arachnoid membrane (the subarachnoid space). They are filled with cerebrospinal fluid.
Central Nervous System (CNS)
Consists of the brain and spinal cord.
Hypothalamus
Regulates and controls the autonomic nervous system, temperature, appetite, water balance, sleep, and blood vessel constriction and dilation. The hypothalamus is also involved in emotions such as anger, fear, pleasure, pain, and affection.
Nervous System
A complex, highly organized system that coordinates all the activities of the body. This system enables the body to respond and adapt to changes that occur both inside and outside the body.
Somatic Nervous System
Carries messages between the CNS and the body.
Cerebellum
The section below the back of the cerebrum. It is responsible for muscle coordination, balance, posture, and muscle tone.
Medulla Oblongata
The lowest part of the brainstem. It connects with the spinal cord and is responsible for regulating heartbeat, respiration, swallowing, coughing, and blood pressure.
Neuron
The basic structural unit of the nervous system, or nerve cell. It consists of a cell body containing a nucleus; nerve fibers, called dendrites (which carry impulses toward the cell body); and a single nerve fiber, called an axon (which carries impulses away from the cell body).
Spinal Cord
Continues down from the medulla oblongata and ends at the first or second lumbar vertebrae. It is responsible for many reflex actions and for carrying sensory (afferent) messages up to the brain and motor (efferent) messages from the brain to the nerves that go to the muscles and glands.
Cerebrospinal Fluid (CSF)
A clear, colorless fluid that circulates continually between the ventricles and through the subarachnoid space. It serves as a shock absorber to protect the brain and spinal cord. It also carries nutrients... and helps remove metabolic products and wastes.
Meninges
Three membranes that cover and protect the brain and spinal cord.
Parasympathetic
Counteracts the actions of the sympathetic system by slowing heart rate, decreasing respiration, lowering blood pressure, and increasing activity in the digestive tracts.
Sympathetic
Prepares the body to act by increasing heart rate, respiration, and blood pressure, and by slowing activity in the digestive tract. This is known as the fight or flight response.