Nervous System Ch.15 Flashcards
cerebr/o
cerebrum
crani/o
cranium (skull)
encephal/o
brain
gangli/o
ganglion (knot or knotlike mass)
gli/o
glue; neuroglial tissue
kinesi/o
movement
lept/o
thin, slender
lex/o
word, phrase
mening/o…meningi/o
meninges (membranes covering the brain and spinal cord)
myel/o
bone marrow; spinal cord
narc/o
stupor; numbness; sleep
neur/o
nerve
radicul/o
nerve root
sthen/o
strength
thalam/o
thalamus
thec/o
sheath (usually refers to meninges)
ton/o
tension
ventricul/o
ventricle (of the heart or brain)
-algesia…-algia
pain
-asthenia
weakness, debility
-esthesia
feeling
-kinesia
movement
-lepsy
seizure
-paresis
partial paralysis
-phasia
speech
-plegia
paralysis
-taxia
order, coordination
pachy-
thick
para-
near, beside; beyond
syn-
union, together, joined
uni-
one
Functions of the Nervous System
Sensory input: information gathered by sensory receptors
Integration: processing of sensory information
Motor output: activation of effector organs (muscles and glands) to produce a response.
Divisions of the Nervous System
Central nervous system (CNS)
Peripheral nervous system (PNS)
Central Nervous System
- brain and spinal cord
- integration and command center
- nervous tissue classified as white and grey matter
Peripheral nervous system
- All nervous tissue outside the CNS
- Spinal nerves (31 pairs) carry impulse to and from spinal cord
- Cranial nerves (12 pairs) carry impulses to and from the brain.
Neurons (Nerve cells)
Structural units that receive and transmit impulses to other neurons and/or effectors
- long lived
- Amitotic…except for hippocampus & olfactory receptors
- high metabolic rate
- identified by the direction of impulses flow:
- afferent: away from sensory source, to the CNS
- efferent: away from CNS, to the effectors (muscles/gland)
Astrocytes
Neuroglia of the CNS
- Most abundant, versatile, and highly branched glial cells
- star shaped
- cling to neurons and capillaries
- Help determine capillary permeability
- guide migration of young neurons
- adjacent cells are connected via gap junctions
Microglia
Neuroglia of the CNS
-migrate toward injured neurons
-Transform into special macrophages undergo phagocytosis
-Provide immunological role
microglial activation is common in all neuroinflammatory disorders…alzheiners, parkinsons, stroke, MS…
Ependymal Cells
Neuroglia of the CNS
- May be ciliated
- line the central cavities of the brain and spinal column
- secretes CSF
- Cilia facilitate CSF movement.
Oligodendrocytes
Neuroglia of the CNS
- branched cells with few processes
- processes wrap CNS nerve fibers
- form insulating myelin sheaths
- disruption of sheath causes MS
Major structures of the brain
Cerebrum
Cerebellum
Diencephalon
Brainstem
Cerebrum
Largest uppermost portion of brain
- divided into 2 hemispheres
- each hemisphere divided into 5 lobes
Functions of cerebrum
- sensory perception and interpretation
- language
- voluntary movement
- memory
- emotions such as fear, rage, anger, food enjoyment, sexual behavior (limbic system)
Cerebellum
Second largest structure of the brain
- posterior portion of the skull
- function in movement, posture, balance
- coordinates and refines (signal from cerebrum) for muscle movement
Diencephalon
includes thalamus, and hypothalamus
- thalamus: receives all sensory stimuli except olfactory and processes/transmits to appropriate center in cerebrum. Also, receives impulses from cerebrum and relays to motor nerves
- hyopthalamus: regulates involuntary activities (heart rate, body temp, fluid balance) and many endocrine functions.
Brain Stem
Connects spinal cord to the brain
- controls automatic behaviors necessary for survival
- contains fiber tracts connecting higher and lower neural centers
- Three regions
- medulla oblongata: attaches to spinal cord
- pons: bridge connecting midbrain to medulla
- midbrain: separates cerebrum from brainstem
Brain stem: medulla oblongata (3 centers)
Cardiovascular center
Respiratory center
Additional reflex centers regulate…vomiting, hiccuping, swallowing, coughing, sneezing.
Meninges of the brain
CT membranes that protect the brain and spinal cord, 3 parts
Dura mater: superficial; bilayer structure
Arachnoid mater: thin; inferior to the dura
Pia mater: layer of delicate, vascularized CT, clings tightly to the cortex surface
Function and Organization of Peripheral Nervous System
2 divisions: Sensory (afferent) and Motor (efferent)
- Sensory consists of Somatic and Visceral
- Motor consists of Somatic nervous system and Autonomic nervous system (ANS)
- ANS consists of sympathetic and parasympathetic divisions
Cranial Nerves
12 pairs
- identified by number and name (occurs from anterior to posterior)
- Named according to structures they serve or their functions.
- may have one or more than three functions
Spinal Nerves
31 pairs of mixed nerves
- emerge from intervertebral spaces of the spinal column
- identified based on their vertebra exit point
- each has two points of attachment:
- anterior root: motor fibers/efferent qualities
- posterior root: sensory fibers/afferent qualities
Motor division of the PNS
Motor neurons send impulses
- Somatic nervous system (SNS): regulates skeletal muscles such as walking and talking
- Autonomic nervous system (ANS): regulates visceral muscles such as the heart rate and peristalsis, and glandular and secretory activity.
Autonomic nervous system
consists of two subdivisions that regulate involuntary body functions and usually oppose the action of the other.
- sympathetic (fight or flight): increase heart rate, constricts blood vessels, and raises BP to deal with crisis.
- parasympathetic (rest and digest): slows heart rate, increases glandular secretions, relaxes sphincters.
