Exam 3: Chapter 11 Flashcards
nervous system is…
master controlling and communicating system of body
What are the 3 overlapping functions of the nervous system?
sensory input, integration, and motor output
sensory input
Information gathered by sensory receptors about internal and external changes
integration
Processing and interpretation of sensory input
motor output
Activation of effector organs (muscles and glands) produces a response
what is a synapse?
when sensory nerves communicate with each other
“fight” or “flight”
driven by the sympathetic nervous system responding to stressful situations
“rest and digest”
the parasympathetic nervous system predominates these conditions
central nervous system (CNS)
brain and spinal cord of dorsal body cavity; integration and control center
peripheral nervous system (PNS)
the portion of the nervous system outside C S; consists mainly of nerves that extend from brain and spinal cord
The two functional divisions of the PNS are….
Sensory (afferent) and motor (efferent)
Sensory Division
▪ Somatic sensory fibers: convey impulses from skin,
skeletal muscles, and joints to CNS
▪ Visceral sensory fibers: convey impulses from visceral
organs to CNS
Motor Division
▪ Transmits impulses from CNS to effector organs
– Muscles and glands
▪ Two divisions
– Somatic nervous system
– Autonomic nervous system
somatic nervous system
somatic motor nerve fibers conduct impulses from CNS to skeletal muscle; voluntary nervous system
autonomic nervous system
consist of visceral motor nerve fibers; regulates smooth muscle, cardiac muscle, and glands; involuntary; 2 subdivisions: sympathetic and parasympathetic
what are neuroglia?
(glial cells) are small cells that surround and wrap delicate neurons (cells that transmit electrical signals)
Four main neuroglia that support CNS…
astrocytes, microglial cells, ependymal cells, oligodendrocytes
Astrocytes
Most abundant, versatile, and highly branched of glial
cells; cling to neurons, synaptic endings, and capillaries
Microglial Cells
Small, ovoid cells with thorny processes that touch
and monitor neurons; Migrate toward injured neurons; Can transform to phagocytize microorganisms and
neuronal debris
Ependymal Cells
Range in shape from squamous to columnar; May be ciliated (Cilia beat to circulate CSF); Line the central cavities of the brain and spinal column; Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cells
Oligodendrocytes
branched cells; processes wrap CNS nerve fibers, forming insulating myelin sheaths in thicker nerve fibers
Neuroglia found in PNS
satellite cells (similar to astrocytes in CNS); Schwann cells (surround all peripheral nerve fibers and form myelin sheaths in thicker fibers)
Neurons
nerve cells; structural units of the nervous system; large, highly specialized and conduct impulses; all have a cell body
satellite cells
surround neuron cell bodies in PNS and function similar to astrocytes of CNS
Schwann cells
surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers
Neuron cell body
also called perikaryon or soma; synthesizes proteins, membranes, chemicals; most are located in CNS
dendrites
Motor neurons can contain 100s of these short, tapering, diffusely branched processes
