Lecture 13 content Flashcards
What are the functions of the nervous system?
- Awareness
- coordination and control
- memory and learning
- establishing patterns of response
What makes up the CNS?
- Brain
- Spinal cord
What makes up the PNS?
Cranial nerves - motor and sensory nerves
Spinal nerves - motor and sensory nerves
- controls skeletal muscle contraction
- voluntary and involuntary/ reflexive control
What makes the ANS?
Autonamic nervous system
- sympathetic - (thoracolumbar) division (speeds heart)
- parasympathetic - (craniosacral) division (slows heart rate)
- controls smooth muscle contraction ( gut and vasculature)
- cannot control (involuntary)
What are the components of a Generic Neuron?
- Soma
- Dendrites
- Axon
- Synaptic terminals
Soma (cell body)
Nucleus, mitochondria
* most lack centrioles ( nerve cells cant divide)
Dendrites
receives input from environment or other cells
Axon
(cord) - conducts nerve impulse
- hollow extension of soma - cytoplasm
- insulated with myelin shealth = helps preserve/ conduct speed
Synaptic terminals
output to muscle/gland/nerve
Anaxonic
dendrites and axons look alike - CNS
Bipolar
soma are situated between dendrite and axon
- rare: sight, smell, hearing (special senses)
Unipolar
soma to one side of axon and dendrite
= SENSORY NERVE endings of the PNS
Multipolar
Several dendrites and single axon
- COMMON IN CNS, motor nerves skeletal muscles
Afferent Axons
SAD MEV
- sensory nerves
- brings sensory info into CNS from tissues and organs
Efferent Axons
SAD MEV
- motor nerves
- carry motor commands from CNS to muslces/glands
Sensory (affrent) 3 types of receptors
IN
- exterocepters : (enviorment) - touch, temp
- proproceptors : (position of muscles and joints)
- interoceptors : - internal enviorment (GI, UG, CV)
2 types of Motor (effrent)
EXIT
Somatic (PNS) = Skeletal muscle
Visceral motor (ANS) = gut
What are the functions of Interneurons in the CNS?
(in between neurons)
- connect between sensory and motor neurons
- Coordinate sensory input and motor output
- Outnumber all other types of neurons
Where is white matter or myelinated axons in the CNS found?
tracts, columns, commissures (inside brain)
Where is white matter or myelinated axons in the PNS found?
Nerves (outside of bone)
Where is grey matter or group of cell bodies in the CNS?
Nuclei ( cluster)
Where is grey matter or group of cell bodies in the PNS?
Ganglia (ganglion)
What are the neuroglia for the PNS?
- Satellite cells
2. Schwann cells
Neuroglia
Cells that support
What are the neuroglia in CNS?
Astrocytes
Oligodendrocytes
Microglia
satellite cells
- surround neuron cell bodies
- exchange of nutrients/waste
Schwann cells
- sheath of myelin that surrounds axon
- aid in repair/regeneration of damage nerves
- SINGLE axon
Astrocytes
- 3-D structure frame work
- forms blood brain barrier
- growth and repair
- interstitial fluid balance in neural tissue
Oligodendendrocytes
octopus (many axons)
- sheath of myelin wraps axons of several cells
- insulates each axon from others
- binds multiple neurons together (support)
Microglia
(janitors)
- small cells with several small branches
- removal (phagocytosis) of debris and pathogens
Endoneurium
(Schwann cells) AROUND AXON
Perineurium
Bundles SEVERAL AXONS into FASCICLE
Epineurium
bundles SEVERAL FASCICLES into a nerve
how does a nerve get destroyed?
- axons retracts
- myelin sheath misalignment
- Re-aquisition of target is imited
- age dependent if axon will grow back
Demyelinstion Pathologies
- where
- varys
- caused
- examples
- occurs in CNS and PNS
- varying degrees of numbness/paralysis
- caused by poisoning, disease, genetics
Ex: - heavy metal poisoning (mercury and lead)
- bacterial insult (diptheria)
Immune system system dysfunction (multiple sclerosis)
Rabies Virus
- travels PNS to CNS (nervous tissue) 100% mortality**
- carried by carnivorous animals
- body fluid transfer ( blood, saliva)
- convulsions, coma, death
Gullian - Barre syndrome
autoimmune disease
- attacks myelin in PNS
- weakness, tingling, +/- paralysis
Rabies progression
- tissue type
- distance from CNS
- strain of rabies virus
Milwaukee proticol
- 11/38 patients have survived
- heavy does of antiviral drug
- chemically induced coma
