Lab9a- Nervous System Histology Flashcards
What are the organs of the nervous system?
- brain
- cranial nerves
- spinal chord
- spinal nerves
What are the organs of the nervous system is composed of?
•nervous tissue
How many subdivision is there in the nervous tissue?
•2
What are the two subdivisions of the nervous system?
- neurons
* neuroglial cells
What are neurons?
• the functional cells of the nervous system
Why are neurons called the functional cell?
• because they are capable of conducting electrical impulses
What forms she neurons bundle together?
• nerves
What are neuroglial cells?
• group of different types of cells that perform support function for neurons
What is a characteristic of neuroglial cells?
- smaller than neurons
* more numerous
How many types of neuroglial cells is there?
• 6
What are the 6 types of neuroglial cells?
- Oligodendrocytes
- Microglial cells
3 Astrocytes - Ependymal cells
- Schwann cells
- Satellite cells
What are the 4 neuroglial cells that can only be found in the central nervous system? (CNS)
- Oligodendrocytes
- Microglial cells
3 Astrocytes - Ependymal cells
What are the 2 neuroglial cells found in the peripheral nervous system (PNS)
- Schwann cells
6. Satellite cells
What composes the central nervous system? (CNS)
• brain and spinal chord
What composes the peripheral nervous system? (CNS)
• cranial and spinal nerves
How can neurons be classified?
- structural differences
* functional differences
What are the main components of a neuron anatomy?
- cell body
- dendrites
- axon
- axon terminals
- initial segment
What are the types of polar a neuron can be?
- multipolar
- bipolar
- unipolar
What are the characteristics of a multipolar neuron?
- 2+ dendrites
- single axon
- most common
- motor neurons to skeletal muscle
What are the characteristics of a bipolar neuron?
- 2 distinct processes
- cell body in the middle
- not very common
- found in special sense organ like eye
What are the characteristics of a unipolar neuron?
- axon and dendrites are fused
- cell body bulges out
- most seen in PNS
- dendrites arise from initial segment
What does the cell body contain?
• nucleus and organelles
What are the organelles of the cell body?
- mitochondrion
- cytoplasm
- nucleus
- nucleolus
What does the cell body do??
- receives impulses from dendrites
* conducts impulse to axon
What is another name for the cell body?
•soma
What are dendrites?
- branched processes at proximal end
* extend from cell body
What does dendrites form?
• synapses with axon
What does a dendrite do?
- stimulated by preceding cell
* conducts impulses to cell body
What is the axon hillock?
• wonder base of axon
What happens at the axon hillock?
• axon arises from cell body
What is an axon?
• single process from cell body
What does the axon do?
• carries impulses away from cell body
Where does the axon end??
• at axon terminals
What is the myelin sheath?
• axon covering of some peripheral neurons
What is the myelin sheath composed of?
• lipoprotein molecules w/in Schwann cells
What is the outer layer of myelin sheath called??
• neurilemma
What is a Schwann cell?
• neuroglial cell from PNS
Where can you find a Schwann cell?
• wrapping around axon like a jelly roll
What does the Schwann cell produce?
• myelin sheath
What is the node of Ranvier?
• gap in myelin sheath
What happens at the anode of Ranvier?
• nerve impulse moves down axon from node to node
What are the axon terminals?
• branched distal end of axon
What does the axon terminals form?
• synapses with dendrites
What does the axon terminals store?
• neurotransmitter
What are the 2 important roles of the spinal chord?
- Convey sensory information
2. Initiates motor command
How many spinal nerve pairings is there?
• 31
To what is continuous the spinal chord??
• medulla oblongata
Where on the skull does the spinal cord exit?
• foramen magnum
What does the spinal cord descend through?
• spinal cavity
How is the spinal cavity formed?
• through the vertebral canals
What is fused to the surface of the spinal cord?
• pia mater
What is the conus medullaris?
• cone shaped end to the spinal cord
Where is the conus medullaris located in an adult?
• around L1 or L2 vertebrae
What fills the spinal cavity from the point of conus medullaris and on?
• only nerves
What does cauda equina mean?
• horse tail
What is the cauda equina?
• collection of spinal nerves extending from conus medullaris
What does the film terminals serve for?
• anchors
How many pairs compose the cervical nerves?
•8
Through what does the cervical nerves run?
• C1- C8
Where does the cervical nerves exit?
• between cervical vertebrae
How many pairs for the thoracic nerves?
• 12
Through what does the thoracic nerves run?
• T1-T2
Where does the thoracic nerve exit?
• between thoracic vertebrae
How many pairs compose the lumbar nerves?
• 5
Through where does the lumbar nerves run??
• L1-L5
Where does the lumbar nerve exit at?
• through sacral foramina
How many nerve pairs compose Coccygeal nerves ?
• 1
Through where does the coccygeal nerves run?
• Co1
Where does the coccygeal nerve exit?
• below sacrum
What does gray matter consists of?
- cell bodies of neurons
- unmyelinated axons
- neuroglia
How is gray matter arranged?
• regions called horns
What does each horn in gray matter contain?
• nucleus
What is the nucleus in gray matter?
• collection of cell bodies located w/in the CNS
What does the sensory nuclei do?
• receives incoming sensory information
What does the motor nuclei do?
• sends motor command
What is the collection of cells bodies located OUTSIDE the CNS called?
• ganglion
What is a nerve?
• bundle of axons traveling together outside the CNS
What is the nerve root?
• point at which the nerve connects with the spinal chord
Central canal
- runs length of spinal cord
* contains cerebrospinal fluid (CSF)
Dorsal gray horn
- posterior gray horn
* location of sensory nuclei
Lateral gray horn
- only in thoracic and lumbar regions
* location of motor nuclei to internal organs
Central gray horn
- anterior gray horn
* motor nuclei to skeletal muscles
Gray commissure
• connection between 2 sides of spinal cord
Central root
- contains axons or motor neurons
* carries motor commands
Dorsal root ganglion
• contains cells bodies
Dorsal root
- contains axons or sensory neurons
* carries sensory information
Spinal nerve
• contains sensory and motor neurons
What is white matter primarily composed of?
• myelinated axons
How is the white matter arranged?
- columns
* funiculi
What does each column carrie?
• nerve tracts
What is a tract?
• bundle of myelinated axons
Where are these tracts located??
• totally inside the CNS
To where does ascending tracts carry information?
• brain
To where does descending tracts carry information??
• spinal nerves
Dorsal white column
• carries ascending sensory tracts
Ventral white column
• carries ascending and descending sensory motors
Front line
• anterior median fissure
Back line
• Posterior median sulcus
Central white commissure
- connects central white columns
* middle center
Lateral white column
• carries ascending sensory tracts and defending motor tracts
What is a plexus?
• groups of adjacent nerves
How many plexus are there?
• 4
What are the 4 plexus?
- Cervical
- Brachial
- Lumbar
- Sacral
What is the major nerve of the cervical plexus?
• phrenic
What does phrenic innervate?
• muscle- diaphragm
What are the 5 nerves of the brachial plexus??
- Axillary
- Musculocutaneous
- Median
- Ulnar
- Radial
What does the nerves in brachial plexus intervene?
• skin and muscle
Where does the axillary innervate skin?
Shoulder
Where does the axillary innervate muscle?
• deltoid muscle
Where does the musculucutaneous innervate skin?
• Lateral foreman
Where does the musculucutaneous innervate muscle?
• flexor muscle of arm
Where does the median innervate skin?
• anterolateral hand
Where does the median innervate muscle?
• flexor muscles of forearm and finger flexor
Where does the ulnar innervate skin?
• medial hand
Where does the ulnar innervate muscle?
Wrist and many hand muscles
Where does the radial innervate skin?
• posterolateral arm
Where does the radial innervate muscle?
• Triceps brachii and extensor muscles of forearm and wrist
What are the 3 nerves of the lumbar plexus?
- Lateral femoral cutaneous
- Femoral
- Obturator
- Saphenous
Where does the lateral femoral cutaneous innervate skin?
• anterior, lateral, posterior thigh
Where does the lateral femoral cutaneous innervate muscle?
• does not
Where does the femoral innervate skin?
- anteriomedial thigh
* medial leg and foot
Where does the femoral innervate muscle?
• anterior thigh muscles
Where does the obturator innervate skin?
• medial thigh
Where does the femoral innervate skin?
• adductor muscle of thigh
Where does the saphenous innervate skin?
• medial leg
Where does the femoral innervate muscles?
• does not
What are the 3 nerves of the sacral plexus?
- Sciatic
- Tibial
- Common fibular
Where does the sciatic innervate skin?
• does not
Where does the sciatic innervate muscle?
• posterior thigh muscle
Where does the tibial innervate skin?
• posterior leg and sole of foot
Where does the tibial innervate muscle?
• knee and ankle plantar flexors
Where does the common fibular innervate skin?
• anterior leg and Dorsum of foot
Where does the common fibular innervate muscle?
• does not
