Nervous System Flashcards
Regulates unconscious body functions to maintain homeostasis
Autonomic Nervous System
Autonomic Nervous System Types
Sympathetic
Parasympathetic
Structures
Nerve Fibers:
(Preganglionic) that arise from thoracic and lumbar regions of the spinal cord join a prevertebral ganglion, then from here nerve fibers exit (postganglionic) and connect to the vital organs
Sympathetic
Functions
• Dilation of pupils of the eyes and bronchioles of lungs
Sympathetic
Structures
Nerve Fibers:
(Preganglionic) that arise from brainstem and sacral region of the spinal cord to join the nerve fibers (postganglionic) in the muscles and glands
Parasympathetic
Functions
• Constricts pupils of the eyes and bronchioles of lungs
Parasympathetic
• Decreases heart rate, blood glucose concentration, blood to skeletal muscles
Parasympathetic
• Increases peristaltic action, glandular secretions, blood to digestive organs
Parasympathetic
• Contracts muscles of gallbladder and urinary bladder
Parasympathetic
• Increases heart rate, blood glucose concentration, blood to skeletal muscles
Sympathetic
• Slows peristaltic action
Sympathetic
• Decreases glandular secretions, blood to digestive organs
Sympathetic
• Relaxes muscles of gallbladder and urinary bladder
Sympathetic
receives stimulus from other neurons or sensory receptors
Dendrite:
- processes stimulus
- contains a nucleus
• Cell body:
transmits stimulus to a gland, muscle, organ, or other
neuron
• Axon:
• Myelinated axons conduct action potentials more quickly (3-15 meters/sec) than unmyelinated due to
Nodes of Ranvier.
disease of myelin sheath that causes loss of muscle function
• Multiple sclerosis:
Types of Neurons
• Multipolar
• Bipolar:
• Pseudo-unipolar:
- many dendrites and a single axon Ex. CNS and most motor neurons
• Multipolar
- one dendrite and one axon
- Ex. Eye and nasal cavity
• Bipolar:
- one axon and no dendrites
- Ex. Sensory neurons
• Pseudo-unipolar:
Neuroglia Characteristics
• Supporting cells for neurons
• More numerous than neurons
• Can divide to produce more cells
- star-shaped
- most abundant
- form blood-brain barrier
Astrocytes:
produce and circulate cerebrospinal fluid (CSF)
• Ependymal Cells:
Types of Neuroglia
Astrocytes:
Ependymal Cells:
Microglia:
Oligodendrocytes:
help remove bacteria and cell debris from CNS
Microglia:
produce myelin sheath in CNS
• Oligodendrocytes:
Many dendrites and one axon
Most motor neurons and most CNS neurons
Multipolar
One dendrite and one axon
Found in special sense organs, such as eye and nose
Bipolar
Appears to have a single axon
Most sensory neurons
Pseudo-unipolar
Highly branched
Provide structural support; regulate neuronal signaling; contribute to blood-brain barrier; help with neural tissue repair
Astrocytes
Epithelial-like
Line ventricles of brain and central canal of the spinal cord, circulate
cerebrospinal fluid (CSF); some form choroid plexuses, which produce CSF
Ependymal cells
Small, mobile cells
Protect CNS from infection; become phagocytic in response to inflammation
Microglia
Cells with processes that can surround several axons;
Cell processes form myelin sheaths around axons or enclose unmyelinated axons in the CNS
Oligodendrocytes
Single cells surrounding axons
Form myelin sheaths around axons or enclose unmyelinated axons in the PNS
Schwann cells
collection of dendrites and cell bodies
Gray matter:
collection of axons and their myelin sheath
• White matter:
Organization of Nervous Tissue
Gray matter:
White matter:
Produce myelin sheath - CNS
Oligodendrocytes
Collection of axons - CNS
Nerve tracts
Collection of cell bodies - CNS
Nuclei
Produce myelin sheath - PNS
Schwann cells
Collection of axons - PNS
Nerves
Collection of cell bodies - PNS
Ganglion
• Outside of cell is more + (Nat)
• Inside of cell is more - (K+)
Resting Membrane Potential
- always open
- K+ channels
• Leak ion channels:
- closed until opened by specific signal
- Na +channels
Gated ion channels:
In a —, there is a higher concentration of K* (purple circles) inside the cell membrane and a higher concentration of Na* (pink circles) outside the cell membrane. Because the membrane is not permeable to negatively charged proteins (green) they are isolated to inside of the cell membrane.
resting cell
The —— helps maintain the differential levels of Na+ and K+ by pumping three Na+ out of the cell in exchange for two K* into the cell. The pump is driven by ATP hydrolysis.
sodium-potassium pump
The —- is established when the movement of K+ out of the cell is equal to the movement of K+ into the cell.
resting membrane potential
• “Electricity” that cause depolarization and repolarization
• Change resting membrane potential by activating gated ion channels
Action Potentials
If enough Na + enters then —- is reached more Na + channels open
threshold
• Once threshold is reached — applies
all or none law
continue until Na+ channels close, K+ channels open, and repolarization occurs
Action potentials
where an axon attaches to a muscle, gland, organ, or other neuron
- involved with release of neurotransmitters
- Ex. Neuromuscular junction
Synapse
CNS synapses, ANS synapses, and neuromuscular junctions
Acetylcholine (ACh)
Excitatory or inhibitory
Acetylcholine (ACh)
Alzheimer disease (a type of senile dementia) is associated with a decrease in acetylcholine-secreting neurons. Myasthenia gravis (weakness of skeletal muscles) results from a reduction in acetylcholine receptors.
Acetylcholine (ACh)
increase the release and block the reuptake of norepinephrine, resulting in overstimulation of postsynaptic neurons.
Cocaine and amphetamines
(a type of senile dementia) is associated with a decrease in acetylcholine-secreting neurons.
(weakness of skeletal muscles) results from a reduction in acetylcholine receptors.
Alzheimer disease
Myasthenia gravis
Selected CNS synapses and some ANS synapses
Norepinephrine (NE)
Excitatory
Norepinephrine (NE)
Cocaine and amphetamines increase the release and block the reuptake of norepinephrine, resulting in overstimulation of postsynaptic neurons.
Norepinephrine (NE)
It is involved with mood, anxiety, and sleep induction. Levels of serotonin are elevated in schizophrenia (delusions, hallucinations, and withdrawal).
Drugs that block serotonin transporters, such as prozac, are used to treat depression and anxiety disorders.
Serotonin
Generally inhibitory
Serotonin
CNS synapses
Serotonin
Levels of serotonin are elevated in (delusions, hallucinations, and withdrawal).
Drugs that block serotonin transporters, such as, are used to treat depression and anxiety disorders.
schizophrenia
prozac
Parkinson disease (depression of voluntary motor control) results from destruction of dopamine-secreting neurons.
Dopamine
Excitatory or inhibitory
Dopamine
Selected CNS synapses and some ANS synapses
Dopamine
(depression of voluntary motor control) results from destruction of dopamine-secreting neurons.
Parkinson disease
Drugs that increase GABA function have been used to treat epilepsy (excessive discharge of neurons).
Gamma-aminobutyric
acid (GABA)
Inhibitory
Gamma-aminobutyric
acid (GABA)
CNS synapses
Gamma-aminobutyric
acid (GABA)
Drugs that increase GABA function have been used to treat — (excessive discharge of neurons).
epilepsy
Glycine receptors are inhibited by the
poison strychnine. Strychnine increases the excitability of certain neurons by blocking their inhibition. Strychnine poisoning results in powerful muscle contractions and convulsions. Tetanus of respiratory muscles can cause death.
Glycine
Inhibitory
Glycine
CNS synapses
Glycine
Increases the excitability of certain neurons by blocking their inhibition.
results in powerful muscle contractions and convulsions.
of respiratory muscles can cause death.
Strychnine
Strychnine poisoning
Tetanus
The opiates morphine and heroin bind to endorphin receptors on presynaptic neurons and reduce pain by blocking the release of a neurotransmitter.
Endorphins
Inhibitory
Endorphins
Descending
pain pathways
Endorphins
The opiates — bind to endorphin receptors on presynaptic neurons and reduce pain by blocking the release of a neurotransmitter.
morphine and heroin
involuntary response to a stimulus
Reflexes
path reflex travels
• Reflex arc:
Components of Reflex Arc
- Sensory receptors:
- Sensory (afferent) neurons:
- Interneurons (Association) neuron:
- Efferent (motor) neurons:
- Effector:
- pick up stimulus
- in skin
Sensory receptors:
send stimulus to interneurons in spinal cord
Sensory (afferent) neurons:
- located in CNS and connect to motor neurons
Interneurons (Association) neuron:
send response to effector
Efferent (motor) neurons:
muscle, gland, or organ
- Effector:
Neuronal Pathways Types
• Converging:
• Diverging:
two or more neurons synapse same neuron
- allows info. to be transmitted in more than one neuronal pathway to converge into a single pathway
Converging:
- axon from one neyron divides and synapses with more than one neuron
- allows info. to be transmitted in one neuronal pathway to diverge into 2 or more pathways
Diverging:
Consists of brain and spinal cord
Brain in brain case:
Spinal cord in vertebral column:
Central Nervous System
• Extends from foramen magnum to 2nd lumbar vertebra
• Protected by vertebral column
Spinal nerves allow movement
• If damaged paralysis
can occur
Spinal Cord
• Contains 3 columns dorsal, ventral, lateral columns
• Ascending tracts:
axons that conduct action potentials toward brain
• Descending tracts:
axons that conduct action potentials away from brain
White Matter in Spinal Cord
axons that conduct action potentials toward brain
• Ascending tracts:
axons that conduct action potentials away from brain
• Descending tracts:
3 columns White Matter in Spinal Cord
dorsal, ventral, lateral columns
• Spinal cords Extends from — to
foramen magnum , 2nd lumbar vertebra
• Posterior horns:
contain axons which synapse with interneurons
• Anterior horns:
contain somatic neurons
• Lateral horns:
contain autonomic neurons
• Central canal:
fluid filled space in center of cord
Gray Matter in Spinal Cord
contain axons which synapse with interneurons
• Posterior horns:
contain somatic neurons
• Anterior horns:
contain autonomic neurons
• Lateral horns:
fluid filled space in center of cord
• Central canal:
• Arise along spinal cord from union of dorsal roots and ventral roots
• Contain axons sensory and somatic neurons
• Located between vertebra
• Categorized by region of vertebral column from which it emerges (C for cervical)
31 pairs
• Organized in 3 plexuses
Spinal Nerves
• Spinal nerves C1-4
• Innervates muscles attached to hyoid bone and neck
• Contains phrenic nerve which innervates diaphragm
Cervical Plexus
• Originates from spinal nerves C5-T1
Supply nerves to upper limb, shoulder, hand
Brachial Plexus
• Originates from spinal nerves L1 to S4
• Supply nerves lower limbs
Lumbosacral Plexus
• Fluid that bathes the brain and spinal cord
Cerebrospinal Fluid
• It is the buildup of fluid in cavities called ventricles deep within the brain.
The excess fluid increases the size of the ventricles and puts pressure on the brain.
• Cerebrospinal fluid usually flows through the ventricles and bathes the brain and spinal column.
Hydrocephalus
is in constant circulation within the ventricles of the brain and serves many crucial functions:
• 1) it acts as a “shock absorber” for the brain and spinal cord;
• 2) it acts as a vehicle for delivering nutrients to the brain and removing waste from it; and
• 3) it flows between the cranium and spine to regulate changes in pressure.
CSF
• The causes of - (excess fluid in the brain) are poorly understood.
Hydrocephalus
• The hydrocephalus present at birth (—) may be the result of a brain defect restricting the flow of cerebrospinal fluid (CSF).
congenital hydrocephalus
•• Hydrocephalus that develops in adults and children (—-)
is often caused by an illness or injury that affects the brain.
acquired hydrocephalus
Hydrocephalus that develops in older people (—-) may also be the result of an infection, illness or injury, but in many cases it’s not clear what causes the condition.
normal pressure hydrocephalus
brain has three basic sections:
Forebrain
Midbrain
-Hindbrain
: The biggest part of the brain.
Forebrain
Major Parts: thalamus, hypothalamus, limbic system (hippocampus, amygdala, and septum), and the cerebrum
Forebrain
: the most primitive and basic of the brain regions, deals with basic bodily coordination and fine motor skills.
Hindbrain
Major Parts: medulla, cerebellum, pons
Hindbrain
Components:
- Medulla oblongata
- Pons
- Midbrain
Brain stem
Brain stem • Components:
- Medulla oblongata
- Pons
- Midbrain
- Location:
scattered throughout brainstem - Function:
regulates cyclical motor function, respiration, walking, chewing, arousing and maintaining consciousness, regulates sleep-wake cycle
Reticular Formation
Diencephalon Components
Thalamus
• Epithalamus:
- Characteristics:
largest portion of diencephalon - Function:
influences moods and detects pain
Thalamus
Location:
above thalamus
- Function:
emotional and visceral response to odors
Epithalamus:
:
area folds on cerebral cortex that increase surface
Gyri
shallow indentations
• Sulci:
deep indentations
• Fissure:
Long Term Memory Types
DECLARATIVE
(Explicit)
PROCEDURAL
(Implicit)
Facts. Skills.
Knowledge. Concepts
“Text book” learning.
Not tied to time or place
SEMANTIC
Autobiographical
A record of your
experiences and events
Time and place related
EPISODIC
Actions, Skills, How To Do.
PROCEDURAL
(Implicit)
DECLARATIVE
(Explicit) Two types
Semantic
Episodic