need to know Flashcards
central nervous system
brain and spinal cord
Peripheral nervous system
cranial nerves: 12
spinal nerves: 31
dendrites
carry information towards cell
axons
carry information away form cell
neurones
do not continue to divide
glial cells
do continue to divide
more glial cells than neurons
schwann cells
Successive wrapping off the cell membrane form the insulating myelin
Outer surface encased in glycoprotein basement membrane which forms sheath of schwaan
nodes of ranvier
Unmyelinated areas between adjacent schwaan cells
Nerve impulses are generated at these areas
satellite cells
Support neuron cell bodies within ganglia
Oligodendrocytes
provide the insulation (myelin) to neurons in the
central nervous system
microglia
Phagocytes, migratory
Ependymal cells
line ventricles and secrete CSF
Impulse transmission
Na+ higher concentration outside
K+ higer concentarion inside
depolarization
Membrane becomes permeable to Na+ for an instant and they quickly move into the cell
The inner surface of the cell membrane is now more positively charged than the outside
Repolarization
When the cell membrane becomes depolarized, K+ automatically leaves the cell until the cell is back to its resting state
“wave” of depolarization
transmission of an impulse along length of axon
myelin sheath causes the ion exchange to occur only at the NODES which speed up the process
excitatory
they increase the likelihood of a postsynaptic action potential occurring
inhibitory
decrease likelyhood of a postsynaptic action potential .
A=
resting state/ potential
B=
depolarization
C=
depolarization
D=
hyperpolarization
meninges
brain is wrapped in 3 layers of connective tissue
innermost later
pia mater
covers/bound to surface of brain: fibrous layer
arachnoid
thin elastic weblike layer between Pia mater and dura mater
between Pia mater and arachnoid is
CSF
CSF
cerebral spinal fluid: clear liquid protecting brain from mechanical injury; acts as a shock absorber
cerebrum
○ Responsible for higher mental functions
○ Ctrl center
○ Voluntary/conscious activities of body
○ Corpus callosum
Contains thick layers of unmyelinated neurons = gray matter
corpus callous
Major tract of axons that functionally interconnects right and left cerebral hemispheres
ridges
gyri
grooves
sulcus
inner surface of cerebrum
cerebral medulla
made up of myelinated axons=white mater
left hemisphere
analytical and mathematical ability
right hemisphere
creativity
frontal
Anterior portion of each cerebral hemisphere
Body regions with the greatest number of motor innervation are represented by largest areas of motor cortex
parietal
Primary area responsible for perception of somatesthetic sensation
Body regions with highest densities of receptors are represented by largest areas of sensory cortex
temporal
Contain auditory centers that receive sensory fibers for cochlea
Interpretation and association of auditory and visual information
occipital
Primary area responsible for vision and coordination of eye movements
cerebellum
Coordinates muscle mvmts, ctrls balance, posture, & coordination
brain stem
Serves as the place of entry or exit for 10/12 cranial nerves
○ Lowest part = medulla oblongata/medulla
■ Ctrls involuntary functions: breathing, BP, HR, digestion, swallowing, coughing
○ Above medulla is pons, then→midbrain
■ Midbrain involved in hearing & vision
thalamus
■ Switch station for sensory input
except smell
■ Epithalamus contains choroid plexus where CSF is formed
■ Immediately below thalamus is hypothalamus
pituitary gland
Ant. pituitary - regulates secretion of hormones of other endocrine glands
sensory (affernt) signals
signals picked up by sensory receptors, carried by nerve fibers of PNS to the CNS
Motor (efferent) signals
carried away from the CNS, innervate muscles and glands
PNS afferent division
Transmits impulses from receptors to the CNS
Somatic afferent fibers
Visceral afferent fibers
Somatic afferent fibers
carry impulses from skin, skeletal muscles, and joints
Visceral afferent fibers
transmit impulses from visceral organs
PNS efferent division
Motor (efferent) division - transmits impulses from the CNS to effector organs; 2 subdivisions:
Somatic nervous system
Autonomic nervous system
Somatic nervous system
provides conscious control of skeletal muscles
Autonomic nervous system
regulates smooth muscle, cardiac muscle, and gland
Proprioceptive senses
detect stretch in tendons and muscle provide information on body position, orientation and movement of body in space
General somatic motor
Signals contraction of skeletal muscles
Under our voluntary control
Visceral motor
Makes up autonomic nervous system (ANS)
Regulates the contraction of smooth and cardiac muscle, controls function of visceral organs
Sympathetic
fight or flight
Parasympathetic
- feed & breed, rest & digest
○ Relaxing effects:
■ Decreases HR
■ Dilates visceral blood vessels
■ Increases digestive activity
What is required for a reflex arc to take plac
Afferent neuron, effferent neuron, interneuron
