Exam 3 Flashcards
(25 cards)
Nervous system
- master controlling and communicating system of body
- cells communicate via electrical and chemical signals which are rapid and specific and usually cause almost immediate response
Functions of the Nervous System
- Sensory or Afferent input
- Integration
- Motor or Efferent Output
Functions of the Nervous System: Sensory or Afferent Input
Information gathered by sensory receptors about internal and external changes
Functions of the Nervous System: Integration
Processing and interpretation of sensory input
Functions of the Nervous System: Motor or Efferent Output
Activation of effector organs (muscles and glands) produces a response
Divisions of the Nervous System
- Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)
Divisions of the Nervous System: CNS
- Brain and spinal cord of dorsal body cavity including cerebrum, cerebellum, brainstem, and spinal cord
- Integration and control center which interprets sensory input and dictates motor output
Divisions of the Nervous System: PNS
- Portion of Nervous system outside CNS
- Consists mainly of nerves that extend from brain and spinal cord AND ganglia
- spinal nerves to and from spinal cord
- -cranial nerves to and from brain
Divisions of PNS
- Sensory (afferent) division
2. Motor (efferent) division
Sensory (afferent) division of PNS
- somatic sensory fibers - convey impulses from skin, skeletal muscles and joints to CNS
- visceral sensory fibers: convey impulses from visceral organs to CNS
Motor (efferent) division of PNS
- Transmits impulses from VNS to effector organs
- muscles and glands
- somatic nervous system
- autonomic nervous system
Motor division of PNS: Somatic Nervous System
- somatic motor nerve fibers
- conducts impulses from CNS to skeletal muscle
- voluntary nervous system
- -conscious control of skeletal muscles
Motor division of PNS: Autonomic Nervous System
- visceral motor nerve fibers
- regulates smooth muscle, cardiac muscle, and glands
- involuntary nervous system
Two functional subdivisions of autonomic nervous system
- sympathetic
- parasympathetic
- work in opposite to each other
Histology of Nervous Tissue
-highly cellular; little extracellular space which is tightly
Two principal cell types of Nervous Tissue
- Neuroglia
2. Neurons (nerve cells)
Neuroglia
small cells that surround and wrap delicate neurons
Neurons
excitable cells that transmit electrical signals
Astrocytes: what are they
(CNS)
- most abundant, versatile, highly branched glial cells
- cling to neurons
Astrocytes: Functions (4)
- support, brace, control chemical environment by neurons
- play role in exchanges between capillaries and neurons
- guide migration of young neurons
- influence neuron functioning
- -respond to nerve impulses and neurotransmitters
- participate in information processing in brain
Microglial Cells
(CNS)
- 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
(CNS)
- Range in shape from squamous to columnar
- may be ciliated
- -cilia beat to circulate CSF
- Line the ventral cavities of the brain and spinal column
- form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cells
Oligodendrocytes
(CNS)
- branched cells
- processes wrap CNS nerve fibers, forming insulating myelin sheaths thicker nerve fibers
Satellite Cells
(PNS)
- surround neuron cell bodies in PNS
- function similar to astrocytes of CNS
