A + P Nervous System I Flashcards
two type of neural tissue
neurons
neuroglia
neurons function
send and receive signals
neuroglia function
support and protect neurons
nervous system anatomical division
Central Nervous System
Peripheral Nervous System
CNS
- consists of
- jobs
- the brain is also…
consists of
-brain
-spinal cord
jobs
-integrates, processes, and coordinates sensory data and motor commands
the brain is also the seat of higher functions, such as intelligence, memory, learning and emotion
PNS
- consists of…
- functions
consists of -cranial and spinal nerves functions -delivers sensory info to the CNS -carries motor commands to the peripheral tissues and systems
PNS functional divisions
Sensory (afferent division)
motor (efferent division)
sensory division function
carries sensory information from receptors to CNS
motor division function
carries motor commands from CNS to PNS muscles and glands
motor division functional division
somatic nervous system
autonomic nervous system
somatic nervous system function
controls voluntary and involuntary skeletal muscle contraction
autonomic nervous system function
provides involuntary automatic regulation of smooth muscle, cardiac muscle,and glandular secretions
autonomic nervous system divisions
sympathetic division (SNS) parasympathetic Division (PSNS)
SNS function
provides a stimulating effect
PSNS
provides a relaxing effect
neuron basic structure
cell body (soma)
axon
dendrites
synapse
cell body composition
single nucleus
cytoplasm (perikaryon: contains mitochondria, ribosomes, endoplasmic reticulum)
cytoskeleton (neurofilaments and neurotubules)
axon
- capability
- axon hillock
- -what is it?
- telodendria
- -what is it?
capability
-long cytoplasmic process capable of propagating an electrical impulse known as an action potential
axon hillock
-wide base of the axon connected to the cell body
telodendria
-the distal end of the axon that is divided into finger-like branches called telodendria
dendrites
- visual characteristics
- function
visual characteristics
-slender processes that extend from the cell body, highly branched
-each branch contains dentritic spines (80-90% of total neuron surface area)
function
-dendritic spines receive information from other neurons
synapse
- function
- two cells of each synapse
function
- a specialized site where the neuron communicates with another cell
- two cells
- -presynaptic cell (sends the message; usually a neuron)
- postsynaptic cell (receives the message, can be another neuron or other type of cell)
types of synapses
- neuromuscular
- neuroglandular
neuromuscular
-synapse between a neuron and a muscle
neuroglandular
-synapse between a neuron and a gland
synaptic cleft
-what is it?
small gap between the pre-synaptic and post-synaptic cells
communication across synaptic cleft
-how?
- presynaptic terminal releases chemical neurotransmitters
- neurotransmitter release is triggered by an action potential
neurons transmit electrical signals called impulses or _____
action potentials
neuron characteristics
- lifespan
- reproductive capability
- metabolic rate
- -result of the metabolic level
- can live your whole life
- amitotic
- high metabolic rate - need more glucose and O2 than other cells
- -can only live for a few minutes without O2
structural classification of neurons
anaxonic neurons
bipolar neurons
unipolar neurons
multipolar neurons
anaxonic neurons
- location
- visual characteristics
location -found in the brain and sense organs visual -two or more processes -dendrites cannot be distinguished from axons
bipolar neurons
- location
- visual characteristics
location
-found only in sensory organs (ex. receptor cells in the retina, nasal passages)
visual
-two processes that extend from the cell body: one is a fused dendrite and the other is an axon
unipolar neurons
- location
- visual characteristics
location
-found in the PNS in the dorsal root ganglia of the spinal cord, and the sensory ganglia of cranial nerves
visual
-contain a single very long axon emerging from the cells body
-axon consists of a central (proximal) process and a peripheral (distal) process receiving impulses from a sensory receptor
multipolar neurons
- location
- visual characteristics
location
-most common (99%) and the major neuron in CNS
visual
-two or more processes extend from the cell body
-all are dendrites except for a single long axon
functional classification of neurons
sensory (afferent) neurons
motor (efferent) neurons
inerneurons (association neurons)
sensory neurons
- function
- structural classification
function
-carry impulses toward the CNS
structural
-unipolar in that the cell bodies are found in the ganglia close to the spinal cord
motor neurons
- function
- structural classification
function
-carry impulses away from the CNS
structural
-multipolar cell bodies are located primarily in the CNS (cell bodies form the grey matter of the brain and spinal cord; axons form white matter)
interneurons
- function
- structural classification
function
-transfer impulses between sensory and motor neurons in the CNS
structural
-multipolar mostly
neuroglia (glial cells) characteristics
supporting cells of the nervous system
found primarily in the CNS