Nervous Tissue Flashcards
What are nerve cells called?
Neurons
What are the supportive cells of the nervous system called?
Glial cells
There are two primary structural divisions of the nervous system. What are they?
The Central Nervous System (CNS)
Peripheral Nervous System (PNS)
The CNS consists of the ______________ and _______________ and acts as the “command center” of the body
Brain
Spinal cord
The PNS consists of nerves conducting impulses to and from the CNS and are composed largely of ________________, small groups of nervous directly outside the CNS
Ganglia
The ________________ nervous system has both CNS and PNS components and processes inputs from the skin, fascia, joints, and muscle into ______________ movement
Sensory
Voluntary
The _________________ nervous system - in addition to its somatic component - also contains a __________________, which consists of input from the stomach and intestines
Somatic
Visceral
What’s the major neurotransmitter of the somatic nervous system?
Aceytlcholine
The ________________ nervous system has CNS and PNS components, too, of which its ______________ functions include the voluntary control of skeletal muscle
Somatic
In the __________________ component of the _____________ nervous system, the involuntary control of smooth muscle, cardiac muscle, and the glands can be further subdivided into the __________________ and ______________ nervous systems
Autonomic
Motor
Parasympathetic
Sympathetic
In the ___________________ response, the body is “resting and digesting.” In the _________________ response, the body is “fighting, flighting, or freezing.”
Parasympathetic
Sympathetic
Which neurotransmitter is primarily responsible for light activity and sleeping?
Norepinephrine
Which neurotransmitter is primarily involved in the sympathetic nervous response?
Epinephrine
From what embryonic layer does nervous tissue develo?
Ectoderm
External layer
What part of the early embryo gives rise to the CNS?
Neural tube
What part of the early embryo becomes the PNS?
Neural crest cells that migrate and differentiate
What is the process of nervous tissue development called in the early embryo?
Neurulation
There are four overarching steps to neurulation:
- ) Neural folds and neural ____________________ form from the neural plate
- ) Neural folds elevate and approach one another
- ) As neural folds prepare to fuse and form the neural _______________ and dorsal epidermis, neural crest cells loosen and become _____________________
- ) The mass of neural crest cells initially lies atop the newly formed neural ________________________
Neural crest cells
Neural tube
Mesenchymal
Neural tube
Nervous tissue is composed of neurons and glial cells.
Neurons have __________ processes while glial cells have _____________ processes. Glial cells support and protect neurons and participate in neural activity, neural nutrition, and defense
Long processes
Short processes
____________________________ cells are the structural and functional unit of nervous tissue. They are distinct cellular entites with processes that are __________________ with other cells, and they have four regions: _________________, ________________, _________________, and ____________________. They have the property of electrical conduction
Neuronal cells
Contiguous
Dendrite, cell body, axon, synpase
The intercellular connection between individual neurons is called the ______________________
Synpase
What part of the neuron is described?
Contains a slightly ovoid, euchromatic nucleus with basophilic cytoplasm due to its rought ER, numerous Golgi, abudant mitochondria, and actin cytoskeleton
Functions as the tropic center, synthesizing neurotransmitters or precursors
Receives nerve endings that convey excitatory or inhibitory stimulated genearted in other nerve cells
Soma or cell body
What color is the cytoplasm of the neuron’s soma or cell body?
Purple
Why does the cytoplasm of neurons stain purple?
Because its basophilic due to the abundant rought ER, Golgi, and mitochondria
In the soma of neurons, ________________________ can be found, which are large granular bodies found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis
Nissl bodies
Identify the cell type and organ
Neuron
Nissl bodies
What are Nissl bodies?
Large granular of rough ER with free ribosomes in the soma of neurons
How does slow axonal occur?
Cytoskeletal elements
How do fast axonal transport occur?
Membrane-bound organelles
_____________________ _________________________ are small membranous protrusions of dendrites that typically recieve input from a single synapse
Dendritic spines
The axon originates at the __________________________ and terminates at the _____________________
Axon hillock
Synapse
The plasma membrane of an axon is called the ___________________
Axolemma
How are neurons classified?
On the number of processes extending from the cell body
___________________ neurons have one axon and two or more dendrites
Multipolar
__________________ neurons have one axon and one dendrite, often function in sensing sight, smell, and balance
Bipolar
_____________________ neurons have a single process that bifurcates near the cell body and are found in spinal nerves and most cranial ganglia
Pseudo-unipolar
There are three types of neurons based on function. What are they?
Sensory (afferent)
Motor (efferent)
Interneuron
_________________ or afferent neurons convey information from receptors to the central nervous system
Sensory
________________ or efferent neurons convey information from the central nervous system to effector cells
Motor
_____________________ establish relationships among other neurons and form complex networks
Interneurons
In the peripheral nervous system, all axons have _____________________, which provide structural and metabolic support
Schwann cells
Small diameter axons of the PNS are _________________________ and are protected by the cytoplasm of Schwann cells while large diameter axons are wrapped by concentric layers of Schwann cells forming a _______________ _________________
Non-myelinated
Myelin sheath
CNS nerve fiber myelination is similar to that of the PNS except that instead of Schwann cells the CNS has ____________________
Oligodendrocytes
_____________________ is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials
Saltatory conduction
Conduction in all nerve fibers depends on the _________________ and ________________ of the axon
Diameter
Myelination
There are two primary glial or support cells of the PNS. What are they?
Schwann cells
Satellite cells
_______________ cells are found only in the PNS and interact with axons and allow for myelination
Schwann cells
In the PNS, __________________ cells form a cover over large neuronal cell bodies
Satellite cells
Each peripheral nerve fiber is surrounded by Schwann cells and a loose vascular supporting connective tissue called the _____________________
Endonerium
Each fascile of the PNS is surrounded by collagenous tissue with a layer of flat epithelial cells call the ___________________
Perineurium
Peripheral nerves with more than one fascile have a layer of loose collagenous tissue that holds fasicles together called the ______________________
Epineurium
Are all nerves in the PNS myelinated?
NO
What are ganglia?
Nerve cell clusters that are located in the autonomic nervous system
The ______________________ or ___________________ ganglia is a cluster of nerve cell bodies in a posterior root of a spinal nerve
Spinal or dorsal root ganglia
_____________________ ganglia deliver information to the body about stress and danger and are located close to either side of the spinal cord
Sympathethic
___________________ ganglia are small terminal ganglia that lie near the organs they innervate
Parasympathetic
___________________ receptors convert environmental stimuli into afferent nerve impulses
Sensory
__________________: orientation, skeletal position, muscle/tendon movement
Proprioception
__________________: touch, pressure, pain, temperature, smell, taste, sight, sound
Exteroreceptors
___________________ sense pressure
Baroreceptors
___________________ sense distention
Interoreceptors
What corpuscle is sensitive to mechanical stimular and light touch?
Meissner’s corpuscle
Meissner’s corpuscle is located in the dermis and concentrated in _____________, _________________ skin
Thick
Hairless
_____________________ corpuscle is sensitive to vibration and pressure, responding to sudden disturbances
Pacinian corpuscle
Groups of ______________________ corpuscles respond to pressure changes and result in the grasp or release of an object
Pacinian
The entire ___________________ corpuscle is wrapped by a layer of connective tissue
Pacinian
What are the three principle structures of the CNS?
Cerebrum
Cerebellum
Spinal cord
The CNS has regions of differential myelin distribution. _____________ matter contains myelinated axons and oligodendrocytes but no cell bodies; _____________ matter contains cell bodies
White matter
Grey matter
White matter contains ____________________ and _______________
Myelinated axons
Oligodendrocytes
_____________ matter contains cell bodies of the CNS neurons
Gray matter
White matter consists mainly of nerve fivers. Neuronal cell bodies, _____________________, and abudant cell processes predominate in the _____________ matter
Astrocytes
Grey matter
___________________ refers to a dense network of fivers from processes of both neurons and glial cells to fill the interneuronal space
Neurophil
Is there connective tissue or an extracellular matrix in nervous tissue?
No
What cells are 10 times more abudant in the brain than neurons?
Glial cells
There are __________ kinds of glial cells
Six
_____________________ produce the myelin sheath in the CNS
Oligodendrocytes
__________________ are unique to the CNS and are important for proper formation of the CNS during embryonic and fetal development; they are the most numerous glial cell and can be found in grey matter
Astrocytes
________________ ______________ are low columnar or cuboidal cells that are often ciliated and line the ventricles of the brain, central canal, and spinal cord; in some locations, they faciliate the movement of cerebrospinal fluid
Ependymal cells
__________________ are less numerous than other glial cells are are small with irregular processes; they originate from blood monocytes, not the neural tube, and they mirgate through neuropil to analyze tissue for damage and invaders
Microglia
What glial cell constitutes the major mechanism of immune response in the CNS?
Microglia
____________ ________________ and ___________ _______________ are glial cells of the PNS
Schwann cells
Satellite cells
CNS tissue lacks proper collagenous supporting tissue and thus the basic arrangement of ___________ and ________ ______________ is consistent throughout the brain
Grey matter
White matter
Grey matter neurons have large nuclei with prominent ______________________
Nuceloli
White matter cells are often found in ________________
Tracts
The ________________ is the gray matter over the surface of the brain
Cortex
The crests of folds of the brain are called _________________
Gyri
Clefts between folds of the brain are ________________
Sulci
There are six layers recognized in the _______________ ___________________
Cerebral cortex
In the cerebral cortex, most neurons are arranged vertically and function in the integration of sensory information and the initiation of voluntary motor responses; however, the most abudant neurons are the efferent ___________________ ____________________
Pyramidal neurons
The ____________________ ____________________ coordinates muscle activity throughout the body
Cerebellar cortex
The cerebellar cortex has three layers: the outer molecular layer, a central layer of ____________________, and an inner ______________ layer
Neurons
Granule
At the interface between the granular and molecular layers of the cerebellar cortex is a single layer of very large neuronal cells bodies of unique __________________ cells whose axons pass through the granular layer to join tracts in the medulla and whose dendrites ramify throughout the molecular layer
Purkinje cells
The _______________ horns of the spinal cord contain motor neurons whose axons make up the ventral roots of spinal nerves
Anterior
The _________________ horns of the spinal cord receive sensory fibers from neurons in the spinal ganglia or dorsal roots
Poster
The _______________ __________________ of the spinal cord develops from the lumen of the embryonic neural tube and is lined by ependymal cells
Central canal
