Chapter 8 Flashcards
What does the nervous system consist of?
Brain, Spinal cord, nerves
What are the functions of the nervous system?
- Regulates and coordinates all body activities
- Detect changes in the internal and external environment, evaluate the information, and respond to the stimuli by brining about bodily responses.
- Center of all mental activity, including thought, learning, and memory
neurology*
the study of the nervous system AND its disorders
neurologist*
the physician who specializes in treating the diseases and disorders of the nervous system
neurosurgery*
any surgery involving the brain, spinal cord, or peripheral nerves
neurosurgeon*
the physician who specializes in surgery of the brain, spinal cord, or peripheral nerves
What are the two subdivisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system* (PNS)
What does the central nervous system consist of?
What is it responsible for?
- The brain and the spinal cord
- processing and storing sensory* and motor information and for controlling consciouness
What is the peripheral nervous system* consist of?
What is it responsible for?
- 12 pairs of cranial nerves and 31 pairs of spinal nerves
- Transmits sensory and motor impulses back and forth between CNS and rest of body
True or False: Basically, the central nervous system (CNS) is the command center, and the peripheral nervous system (PNS) is the messenger.
True. The peripheral nervous system is kept quite busy carrying messages to and from the rest of the body.
What is the PNS made up of?
nerves and ganglion
What is a nerve?
cordlike bundle of nerve fibers that transmits impulses to and from the brain and spinal cord. A nerve is macroscopic-seen without a microscope
What is a ganglion*?
A knotlike mass of nerve cell bodies located outside the CNS
What two divisions does the PNS break down into?
Somatic nerve system and the autonomic nervous system
What do afferent nerves* do?
carry impulses from the body to the CNS
What do efferent nerves* do?
carry impulses from the CNS to the muscles and glands, causing the target organs to do something in response to the commands received
What does the somatic nervous system* (SNS) provide?
voluntary control over skeletal muscle contractions
What does the autonomic nervous system* (ANS) provide?
involuntary control over smooth muscle, cardiac muscle, and glandular activity and secretions in response to the commands of the CNS.
What types of nerves are found in the ANS?
sympathetic* and parasympathetic*
What do sympathetic nerves* regulate?
essential involuntary body functions such as
- increasing heart rate
- constricting blood vessels
- raising blood pressure
- responding to the “flight or fight” response
What do parasympathetic nerves* regulate?
regulates essential involuntary body functions such as
- slowing the heart rate
- increasing peristalsis of the intestines
- increasing glandular secretions
- relaxing sphincters
- therefore, serving as a complement to the SNS and returning the body to a more restful state
__________ nerves carry the impulses from the body to the CNS, while __________ nerves carry the impulses from the CNS to the body.
a. Somatic, autonomic
b. Afferent, efferent
c. Autonomic, somatic
d. Efferent, afferent
b. Afferent nerves are sensory, efferent nerves are motor.
What are the two main types of cells found int he nervous system tissue?
neurons and neuroglia*
Neuron*
What is it known as?
What are its three basic parts?
- the functional unit, the nerve cell
- a cell body, one axon, and one or more dendrites
What is within the cell body?
nucleus and cytoplasm
What is the axon*?
What does it do?
- a single slender projection that extends from the cell body
- conduct impulses away from the cell body
What are some axons covered in?
a myelin sheath*
What is the role of the myelin sheath*?
protects the axon and speeds the transmission of the impulses.
How do you tell the difference between a nerve cell with or with out the myelin sheath?
axons with a myelin sheath look white (making up the white matter of the nervous system) and without look grey (making of the grey matter within the nervous system)
Dendrites
What do they do?
branch extensively from the body (like trees)
-conduct impulses toward the cell body
What is the space between the axon of one neuron and dendrite of another neuron?
a synapse*
What is a synapse*?
the space between the two nerves over which the impulses must cross
What is released into the synapse* to activate or inhibit the transmission of nerve impulses across the synapses?
chemical substances known as neurotransmitters
How are nerves classified?
according to the direction in which they transmit impulses.
Afferent nerves*
What are they also called?
- transmit impulses toward the brain and spinal card
- sensory nerves*
Efferent nerves*
What are they also called?
- transmit impulses away from the brain and spinal cord
- motor nerves*
What are interneurons*?
connecting neurons in the CNS that conduct impulses from afferent nerves to (or toward) motor nerves
What is neuroglia*?
a special type of connective tissue for the nervous system
What is the role of neuroglia*?
provide a support system through phagocytosis* by engulfing and digesting any unwanted substances