Nervous System Flashcards
Types of Supporting Cells
Astrocytes
Microglia
Ependymal cells
Obligodendrocytes
Astrocytes
Star-shaped
Nearly half of all neural tissue
Brace and anchor neurons to their supply line, blood capillaries; form living barrier between capillaries and neuron
Help control chemical environment in brain
Microglia
Spider-like phagocytes that dispose of debris, including dead brain cells and bacteria
Ependymal
Line central cavities of brain and spinal cord.
Ependymal cilia helps circulate CSF, forming protective cushioning around CNS
Obligodendrocytes
Myelin sheath wrappings around nerve fibers in CNS
Types of motor/efferent divisions
Somatic
Autonomic
Types of autonomic divisions
Parasympathetic
Sympathetic
Myelin Sheath
Made up of obligodendrocytes in CNS
Called Schwann Cells in PNS
Protect and insulate nerve fibers
Multipolar neuron
Several processes extending from cell body
Most common
Bipolar neuron
Two processes - an axon and a dendrite
Unipolar neuron
Single process extending from cell body
Very short, and divides almost immediately into proximal (central) and distal (peripheral).
Two neuron functional properties
Irritability
Conductivity
Nerve impulse steps
- Resting Potential
- Local Depolarization
- Depolarization and generation of Action Potential
- Porpagation of the action potential
- Repolarization
- Hyperpolarization
- Return to resting state
Reflex arc steps
- Sensory receptor
- Sensory/afferent pathway
- Integration center (interneuron/synapse in ventral horn gray matter)
- Motor/efferent pathway
- Effector
Cerebrum parts
Sucli Gyri Cerebral Cortex/Gray Matter White Matter (inside) Lobes Hemispheres
Diencephalon/Interbrain parts
Thalamus Hypothalamus - Pituitary gland Epithalamus - Pineal Body - Choroid Process
Brain Stem parts
Midbrain - Cerebral penduncles Pons Medulla Oblongata Reticular Formation
Cerebellum parts
Arbor Vitae
Cerebellar Cortex
Hemispheres
Meninges
Dura mater –> Arachnoid mater –> Subarachnoid Space –> Pia mater
Hydrocephalus
“Water on the brain”
When CSF accumulates and exerts pressure on the brain
Seen mainly in newborns, as fontanels are still present
Concussion
Slight brain injury
Dizzy, “see stars,” or lose consciousness briefly, but no permanent brain damage
Contusion
Marked tissue destruction
Cerebral cortex injured –> may remain conscious
Brain stem injured –> coma, hours to lifetime
Nerve wrappings
Nerve –> Epineurium
Fascicle –> Perineurium
Nerve fiber –> Endoneurium
Autonomic Nervous System
Motor subdivision of PNS responsible for involuntary actions.
- Cardiac and smooth muscle
- Glands
Divided into parasympathetic and sympathetic divisions
Autonomic Nervous System - Nerve Impulse
Nerve impulses typically in three parts: preganglionic axon, ganglion, postganglionic axon
ANS - Sympathetic Division
“Fight or flight;” working full speed when emotionally upset and physically stressed
Thoracolumbar division of spinal cells (T1 - L2)
ANS - Parasympathetic Division
“Resting and digesting” system
When does the nervous system form?
First month of embryonic development
Biggest danger to child during pregnancy?
Maternal infection
- lack of oxygen to brain
- smoking
- radiation
- alcohol
Cerebral palsy
Neuromuscular disability in which the voluntary muscles are poorly controlled and spastic because of brain damage
Anencephaly
Failure of the cerebrum to develop, resulting in a child who cannot hear, see, or process sensory inputs
Spina bifida
Vertebrae form incompletely
Orthostatic hypotension
Type of low blood pressure resulting from changes in body position, such as getting up too quickly and passing out
Arteriosclerosis
Results in a decreasing supply of oxygen to the brain neurons.
Senility
Gradual lack of oxygen due to the aging process.
Forgetfulness, irritability, difficulty in concentrating and thinking clearly, and confusion
Thalamus
Relay station for sensory impulses passing upward to the sensory cortex
Tells us if sensations are nice or bad
Hypothalamus
Regulation of body temperature
Water balance
Metabolism
Pituitary gland
Center for many drives and emotions (limbic system)
Choroid plexus
Forms CSF
Brain stem functions
Houses nuclei that produce the ridigly programmed autonomic behaviors necessary for survival
Controls breathing and blood pressure
Cerebellum functions
Provides the precise timing for skeletal muscle activity
Controls balance and equillibrium
Primary motor area location
Cerebral cortex, anterior to the central sulcus in the frontal lobe
Primary somatic sensory area location
Parietal lobe, posterior to the central sulcus
Fissure
Much bigger and more apparent sulci; separates parietal lobes, for example
Broca’s area
Found at base of precentral gyrus (gyrus anterior to the central sulcus; usually left cerebral hemisphere)
Allows for ability to speak clearly
Wernicke’s area
Allows for ability to speak with accuracy of vocabulary
Nodes of Ranvier
Gaps between Schwann Cells
