nervous tissue Flashcards
a bundle of axons (plus associated connective tissue and blood vessels) located outside the brain and spinal cord is called_
a nerve
small masses of nervous tissue, consisting primarily of neuron cell bodies, that are located outside the brain and spinal cord are called_
ganglia
what are the three major functions of the nervous system
- sensory input: the nervous system uses its millions of sensory receptors to monitor changes occuring both inside and outside the body. The gathered information is called sensory input
- integration: the nervous system processes and interprets sensory input and decides what should be done at each moment - a process called integration
- motor output: the nervous system activates effector organs-the muscles and glands-to cause a response, called motor output
networks of neurons located in the walls of GI tract organs and help regulate digestive system activities is called_
enteric plexuses
structures that monitor changes in the internal and external environment are called_
sensory receptors
what are the two parts the nervous system is divided into
the CNS (central nervous system): consists of the brain and spinal cord
the PNS (peripheral nervous system): consists of nerves that extend from the brain to the spinal cord
spinal nerves carry impulses to and from the _
spinal cord
cranial nerves carry impulses to and from the _
brain
what are the two functional subdivisions of the PNS
- sensory, or afferent division: consists of nnerve fibers that convey impulses to the central nervous system from sensory receptors located throughout the body
- motor, or efferent division: transmits impulses from the CNS to effector organs, which are the muscles and glands (they effect, or bring about a motor response)
what do somatic sensory fibers do?
convey impulses from the skin, skeletal muscles, and joints
what to visceral sensory fibers do?
transmit impulses from the visceral organs (within the ventral body cavity)
what are the two main parts of the motor (efferent) division
- somatic nervous system: composed of somatic motor nerve fibers that conduct impulses form CNS to skeletal muscles. VOLUNTARY NERVOUS SYSTEM (b.c. it allows us to consciously control our skeletal muscles)
- automonic nervous system (ANS): consists of visceral motor nerve fibers that regulate the activity of smooth muscles, cardiac muscles, and glands. INVOLUNTARY NERVOUS SYSTEM (b.c. it regulates activities such as the pumping of our heart, or the movement of food through our digestive tracts.)
what are the two functional subdivisions of the ANS
- sympathetic division: generally supports exercise and emergency actions, ie: “fight-or-flight” responses
- parasympathetic division: generally promotes “rest and digest” activites
what is the enteric nervous system?
involuntary, ENS, “brain of the gut;” consists of neurons in the enteric plexuses that extend the entire length of the GI tract. The sensory neurons monitor changes in the GI tract and the motor neurons help regulate digestive system activites
what two types of cells make up the nervous system
- neurons: nerve cells that are excitable (respond to stimuli), and transmit electrical signals
- neuroglia: support, nourish, and protect the neurons and maintain the interstitial fluid that bathes neurons
when neurons respond to a stimulus and convert it into a nerve impulse, this is called a_
action potential