Exam 1 Flashcards
Neurons
The functional unit of the nervous system
Composed of: Dendrites, Cell body, Axons
Dendrites
Sensory information carried TORWARD cell body (afferent)
Cell body
Interprets information
Axons
Carries action potential AWAY from cell body (efferent)
Neuroglial Cells
Non-neuronal cells which maintain homeostasis, form myelin, and provide support and protection for neurons
CNS: Astrocytes (BBB), ependymal cells (CSF), oligodendrocytes (myelin sheath)
PNS: Neurolemmocytes- Schwann cells (myelin sheath) Satellite cells- Microglial cells (macrophage)
Myelin
Multi-layered lipid and protein covering around some axons
Fx- Insulation, salutatory conduction
Present on axons (White matter)
Not present on all cell bodies, dendrites, terminals, and neuroglia (gray matter)
Sensory
To sense changes in the internal and external environments and send information to CNS Dendrites Afferent neurons (TOWARDS brain)
Integrative
Decides if a response is necessary based on incoming information
Cell bodies
Association neurons
Motor
Send an action potential (motor response) to the appropriate effector to produce the response
Axons
Efferent neurons (AWAY from the brain)
Central Nervous System
Brain
Spinal cord
Peripheral Nervous System
Cranial nerves
Spinal nerves
Action Potential Stages
- Resting state
- Depolarization
- Repolarization
- Hyperpolarization
* All or nothing response*
Resting State (salty banana)
Neuron is not being stimulated
More Na+ outside and more K+ inside
Membrane is polarized (more + outside)
-70 millivolts (intracellular)
Depolarization
Contraction
If stimuli increases membrane potential to -55 millivolts:
Sodium channels open in the membrane and sodium rushes into the cell thus increasing potential up to 30+ millivolts
Repolarization
“Reset”, relaxation
When membrane potential reaches 30+ millivolts:
Sodium channels close and Potassium channels open
(more + outside)
Potassium rushes out of the cell thus returning membrane potential to -70 millivolts
Hyperpolarization
Membrane voltage temporarily decreases to -90 millivolts
Potassium channels remain open for a short period after -70 millivolts has been reached
Resting Membrane Potential
Is re-established when the sodium/potassium pump, pumps 3 sodium ions OUT of the cell and 2 potassium ions IN the cell
Approx. 40% of the ATP’s produced by the neuron is used to drive the pump
Refractory Periods
Absolute: During depolarization + repolarization the neuron can NOT respond to additional information
Relative: During hyperpolarization, neuron can respond if stimulus is large enough to drive potential up to -55 millivolts
Synapse
A junction between 2 neurons or between a neuron and its effector
Excitatory Neurotransmitter
Drives post-synaptic membrane potential towards threshold (more positive)
- Acetylcholine @ neuromuscular junction
- Epinephrine/Norepinephrine during fight or flight
- Dopamine
Inhibitory Neurotransmitter
Drives post-synaptic membrane potential away from threshold (more negative)
- Acetylcholine @ neurocardiac junction
- Dopamine
- GAMA
- Glycine
Cerebral Hemispheres
Responsible for learning, intelligence, behaviors, communication, memory, and recall
Neocortex
Controls skeletal muscle contraction, 5 senses
Cerebellum
Responsible for skeletal muscle coordination, controls muscle tone, and helps maintain equilibrium
Pituitary Gland
“Master gland”
Produces hormones
Anterior: TSH, ACTH, LH, FSH
Posterior: ADH, Oxytocin
Hypothalamus
Contains 5 nuclei: hunger center, thirst center, body temp regulatory center, libido center, aggression center
Brain Stem (Medulla Oblongata)
- Emetic Center
- Cough Center
- Pneumotaxic Center
- Cardiac Inhibitory Center
Meninges
Pia Mater- Innermost layer, blood supply to brain and spinal cord
Arachnoid- Contains CSF and cushions the brain
Dura Mater- Outermost layer, protects brain and spinal cord from trauma
CNS
Astrocytes (BBB)
Ependymal Cells (CSF)
Oligodendrocytes (Myelin Sheath)
PNS
Neurolemmocytes- Schwann Cells (Myelin Sheath)
Satellite Cells- Microglial Cells (Macrophage)
Olfactory Nerve
1.
Sensory
Sends info to hunger center, libido center, neocortex, emetic center
Optic Nerve
2.
Sensory
Shares info with hunger center, emetic center, cerebellum, can cause blindness
Oculomotor Nerve
- Motor
Eye movement/pupil size
Trochlear Nerve
4.
Motor
Extrinsic eye muscles
Trigeminal Nerve
5.
Mixed
Sensory: mouth, teeth, gums
Motor: muscles of mastication
Abducent Nerve
6.
Motor
Movement of eye muscles
Facial Nerve
7.
Mixed
Facial movement, salivation, tears, taste
If lose –> Bells palsy
Vestibulocochlear Nerve
8.
Sensory
Balance and hearing
Glossopharyngeal Nerve
9. Mixed Tongue movement, swallowing Motor: swallowing, salivation Sensory: taste
Vagus Nerve
10.
Mixed
Motor: larynx, abdominal/thoracic viscera
Sensory: GI tract, resp. tract
Spinal Accessory Nerve
11.
Motor
Muscles of neck and shoulder
Hypoglossal Nerve
12.
Motor
Tongue muscles
Spinal Cord
Dorsal Root- Sensory (afferent)
Ventral Root- Motor (efferent)
White Matter –> Axons
Gray Matter –> Nerve cell bodies
Sympathetic
“Fight or flight response”
Arises from the nerves in the thoracic and lumbar region
Main Effects: increased heart rate, dilation of the bronchioles, mydriasis, decreased GI tract motility and secretions, dilation of the blood vessels
Drugs: Catecholamines (epinephrine, norepinephrine, dopamine)
Parasympathetic
“Rest and restore”
Arises from the brain and lumbar regions
Helps modulate and control the sympathetic response
Main Effects: Decreased heart rate, constrictions of the bronchioles, constrictions of the pupil, increased GI motility and secretions
Drugs: Acetylcholine
TSH (anterior)
Thyroid stimulating hormone
Controls metabolism
ACTH (anterior)
Adrenocorticotropic hormone
Inflammation response
LH (anterior)
Luteinizing hormone
Reproduction, stimulates production of corpus luteum
FSH (anterior)
Follicle stimulating hormone
Stimulates productions of the ova in the ovary
ADH (posterior)
Anti-diuretic hormone
Allows you to inhibit production of urine
Oxytocin (posterior)
Stimulates uterine contraction + milk secretion
