Chapter 12 Neural Tissue Flashcards
The Nervous System includes?
-Includes all neural tissue in the body
-Maintains homeostasis
Neural tissue has two kinds of cells what are they
- Neurons
* Cells that send and receive electrical signals - Neuroglia (glial cells)
* Cells that support and protect neurons
cells that send and receive electrical signals
neurons
cells that support and protect neurons
neuroglia
Organs of the Nervous System
- Brain and spinal cord
- Sensory receptors of sense organs (eyes, ears, etc.)
- Nerves connect nervous system with other system
2 Anatomical Divisions of the Nervous System
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
the Central Nervous System (CNS) Consists of what organs
- spinal cord
- brain
Functions of CNS
- Process sensory data from inside and outside body
- Directs activities of peripheral organs (e.g., skeletal
muscles, glands) - Control higher functions of brain (intelligence, memory,
learning, emotion
The Peripheral Nervous System (PNS) consists of ?
Includes all neural tissue outside the CNS
-sensory receptors
-peripheral nerve fibers
Functions of PNS?
- Deliver sensory information to the CNS
- Carry motor commands to periphery
Bundles of axons with connective tissues and blood
vessels
Nerves (peripheral nerves)
Nerves (peripheral nerves)
are Bundles of _____ with connective tissues and blood
vessels
axons
Nerves (peripheral nerves)
function?
Carry sensory information /motor commands in PNS
Nerves (peripheral nerves)
2 examples of nerves
- Cranial nerves — connect to brain
- Spinal nerves — attach to spinal cord
Functional Divisions of the PNS
-Afferent division
-Efferent division
-Carries sensory information from sensory receptors to
CNS
-Receptors
Afferent division
Sensory structures that detect changes or
specific stimuli in body
Receptors
-Carries commands from CNS to peripheral effectors -Effector
Efferent division
Cell or organ that responds to efferent signal
by doing something (EX: muscles, glands)
Effector
The efferent division includes the:
- Somatic nervous system (SNS)
- Autonomic nervous system (ANS)
efferent division that Controls voluntary skeletal muscle
contractions
-somatic motor neurons (somatic reflexes)
Somatic nervous system (SNS)
efferent division that Controls involuntary actions, contractions of
smooth muscle and cardiac muscle, glandular
secretions
-visceral motor neuron
Autonomic nervous system (ANS)
Autonomic nervous system (ANS) has two divisions what are they?
- Sympathetic NS: Stimulates HR, Respirations,
- Parasympathetic NS: Stimulates digestion, Dec
HR, Respirations
division of Autonomic nervous system (ANS)
that Stimulates HR, Respirations or “Flight or Fight”
Sympathetic NS
division of Autonomic nervous system (ANS)
Autonomic nervous system (ANS) that Stimulates digestion, Dec
HR, Respirations or “rest or Digest”
Parasympathetic NS
-cells that sends and receives electrical signals
-The basic functional unit of the nervous system
-Nerve cell specialized for intercellular communication
Neuron
Neurons all exhibit:
- Excitability: Respond to stimuli
- Conductivity: Produce electrical signals that are
quickly carried to cells at distant locations = Action Potential - Secretion: When signal reaches end of nerve fiber,
neuron secretes neurotransmitter to affect next cell
-Large nucleus
- mitochondria (energy)
-RER &
ribosomes (make neurotransmitters)
-Perikaryon
(cytoplasm)
-No Centrioles
-Nissl bodies (gray matter)
The Cell Body
-mitochondria =
-RER and ribosomes make =
-Perikaryon =
-mitochondria (energy)
-RER and ribosomes (make neurotransmitters)
-Perikaryon (cytoplasm)
-Dense areas of RER and ribosomes
-Make neural tissue appear gray (gray matter)
Nissl bodies
Short, highly branched processes
Dendrites
- Fine processes of dendrite branches
- Receive information from other neurons
- 80–90% of neuron surface area
Dendritic spines
-Long, single process from cell body
- Carries action potential to target
- its structure is critical to function
Axon
what are the Structures of the Axon
-Axolemma
-Axoplasm
-Axon hillock
-Collaterals
-Telodendria
-Synaptic terminals
Structure of the Axon: Specialized cell membrane, covers axoplasm
axolemma
Structure of the Axon: Cytoplasm of axon, contains neurofibrils, neurotubules, enzymes,
organelles
axoplasm
Structure of the Axon: Thick section of cell body attached to axon and carries AP to target
axon hillock
structure of axon : Branches of a single axon
collaterals
structure of axon: Fine extensions of distal axon
telodendria
structure of axon: Tips of telodendria, Forms synapse at Target cell, contains synaptic vesicles with neurotransmitters
Synaptic terminal
Area where a neuron communicates
with another cell (neuromuscular, neuroglandular)
The synapse
The synapse parts
- Presynaptic cell-Neuron that sends message
- Postsynaptic cell-Cell that receives message
Part of synapse:
Neuron that sends message
Presynaptic cell
part of synapse: Cell that receives message
Postsynaptic cell
Small gap that separates the presynaptic and
postsynaptic membranes
synaptic cleft
-Chemical messengers released at the presynaptic
membrane
-Travel across the synaptic cleft (short distance, limited
effect)
-Bind to receptors on postsynaptic membrane
-Stimulatory
-Inhibitory
-Broken down by enzymes and parts are reassembled in
synaptic terminal (Recycled)
Neurotransmitters
examples of Neurotransmitters
Acetylcholine,
Dopamine,
Serotonin,
Norepinephrine,
Epinephrin
Structural Classification
of Neurons?
ABUM
-Anaxonic Neurons
-Bipolar Neurons
-Unipolar Neurons
-Multipolar Neurons
are small
no axon
all processes are dendrites
anaxonic neurons
2 processes
-are small
-1 axon
-1 dendrites
bipolar neurons
1 processes
-single, long axon
-cell body to one side
-fused axon & dendrites
unipolar neurons
multiple processes
-long axon
-1 axon
-multiple dendrites
-includes motor neurons that control skeletal muscles
multipolar neurons
functional classification of neuron
SIM
-sensory neurons
-interneurons
-motor neurons
afferent neurons that carry sensory information to the CNS
-unipolar or bipolar cell bodies grouped into SENSORY GANGLIA
sensory neurons
efferent neurons that carry commands from the CNS to periphery
motor neurons
interconnect 2 neurons
interneurons
2 major efferent systems
-somatic motor neurons
-visceral motor neurons
efferent system that carries signals to the skeletal muscles (voluntary control)
-somatic motor neurons
efferent system that carries signals to the smooth muscle ,cardiac muscle, glands (involuntary control)
-visceral motor neuron
-cells that support and protect neurons
-more numerous than neurons 10:1
-smaller than neurons
Neuroglia
neuroglia in CNS (cameo)
-astrocytes
-microglia
-ependymal cells
-oligodendrocytes
star shaped
-maintain BBB (blood brain barrier) which isolates the CNS from systemic blood
-form scar tissue or sclerosis
Astrocytes
-migrate and perform phagocytosis
Microglia
-form epithelium that lines central canal of spinal cord and vesicles of brain
-produce and circulate CSF (cerebrospinal fluid)
ependymal cells
-myelinate CNS axons (myelinated axons appear WHITE= WHITE MATTER
-node (areas without myelination)
-internodes (myelinated areas)
oligodendrocytes
Neuroglia of PNS penis (suck & swallow
-schwann cells
-satellite cells
SURROUND neuron cell bodies in the PNS
satellite cells
-SURROUND axons in the PNS
-provide myelination of a single axon or SURROUND multiple axons
schwann cells
