Exam 1 Flashcards
What is the central nervous system (CNS)?
consists of the brain and the spinal cord, mostly composed of neurons
What is the place where the brain connects to the spinal cord
foramen magnum
What is the peripheral nervous system?
consists of the nerves that carry signals to and from the CNS
What is a nerve?
bundle of long axons that are packed togethr with blood vessels surrounded by connective tissue
How are nerves named?
by their origin or destination
How many cranial nerves and how many spinal nerves are there ?
12 cranial
31 spinal nervous
Sensory function
-gathers information about internal and external environments through
-gathered by sensory division of PNS
What are the two types of sensory division?
Somatic Sensory Divison
Visceral Sensory division
Somatic Sensory division
-neurons carry signals from skeletal muscles, bones, joints, and skin and includes sensory neurons that tranmit signal from organs of vision, hearing, taste, smell, and balance
Viceral sensory divison
transmit signals from organs
Integrative function
performed by CNS (mostly brain) that analyzes and interperts the stimuli and dictates appropriate response
Motor function
performed by efferent (carrying away) division of PNS
two types: Somatic Motor Division and Visceral Motor division
Somatic motor division
signal to skeletal muscles and is under voluntary motor division
Visceral motor division (automatic nervous system)
-signals to thoracic and abdominal viscera
-regulates secretion from glands, contraction of smooth muscle, and contraction of cardiac muscle in the heart (involuntary motor division)
Neuroglial
smaller more prevalent cell in the nervous tissue; does not typically transmit signal, but does other supportive functions
How do neurons send signals?
Based on action potential
How is the cell body held together?
-most metabolically active part
-shape held by neuronal cytoskeleton (intermediate filaments)
-filaments bundle to make larger neurofibrils
Multipolar neurons
-99% of all neurons
-single axon with multiple dendrites (widest variability in shape and size)
Bipolar neurons
-2 processes: one axon and one dendrite
-majority are sensory neurons (located in retina of eye and olfactory epithelium or nasal cavity)
Pseudounipolar neurons
-begin as bipolar neurons but 2 processes fuse to make single axon, as axon extends, it splits:
-One brings stimuli from sensory receptor of the cell body (peripheral process or axon)
-One travels to the spinal cord away from the cell body (central process of axon )
What are the functional classifications of neurons ?
sensory, interneurons, and motor neurons
Sensory (afferent) neurons
-carry signal TOWARD CNS
-Receive signal to move electrial signal to cell body of PNS, Down axon to brain or spinal chord
-Usually pseudounipolar or bipolar bc they only recieive signla from one area
Interneurons (association neurons)
-relay message in CNS (b/t sensory and motor neurons)
-information processing
-most neurons are interneurons
-MULTIPOLAR so they can interact with many other neurons
Motor (efferent) neurons
-carry stimuli away from cell bodies in CNS to muscle and glands
-most multipolar bc they are complicated and require input from many neurons
How many types of neurogila are there ?
6 (4 CNS and 2 PNS)
Astrocytes
-most numerous and largest neurogila
Funcations:
-anchor neurons and blood vessels in place
-regulating the extracellular environment of brain via GAP junctions
-assisting in formation of blood brain barrier
-repairing damaged brain tissue
