Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
Nervous System
Chapters 10 and 11
Learning obejectives
• Major divisions• Cell types• Characterize neurons by their action• Resting to Action Potential• Gray v white matter• Parts of the brain and spinal cord• Cranial and spinal nerves
Major divisions of nervous system
• Central Nervous System (CNS)– Brain– Spinal Cord
• Peripheral Nervous System (PNS)– Cranial nerves– Spinal nerves
Functions of the Nervous System
Types of cells found in Nervous System
• Neuron: sends and receives electrical signals
• Neuroglia: provides support, protection, nourishment for the neurons
Parts of the neuron
1.Dendrites2.Cell body
(Soma)3.Axon–Can have myelin
sheath
• Axon terminals–Contains
neurotransmitters
Three main types of neurons
A.Sensory (Afferent) neurons– To CNS
B.Interneurons–Within CNS
C.Motor (Efferent) neurons– From CNS
Three phases of signal transmission
1.Resting Potential
2.Depolarization
3.Repolarization
Resting potential• Neuron at rest• Intracellular charge is
negative• Potassium (K+) is found on the
inside of the cell• Sodium (Na+) is found on the
outside• Maintained by Na+/K+ pump
Depolarization
• Neuron has been stimulated• Sodium (Na+) “rushes” into the neuron• Inside cell goes from negative to
positive• Send signal (electrical)
Repolarization
• Getting neuron “relaxed” – back to normal
• Three steps:1. Stop sodium coming in2. Allow potassium to leak out3. Na+/K+ pump
Neurons communicating
Electrical chemical electrical
Tracking the flow of information
1.Impulse (electrical signal) to axon terminal
2.Neurotransmitter released from terminal
3.Binds to receptors on next neuron
4.Stimulates next neuron to depolarize and send impulse
Synapse terms• Neurotransmitter released
from the presynaptic membrane (axon)
• Neurotransmitter travels across the synaptic cleft
• Neurotransmitter binds to the receptors on the postsynaptic membrane (dendrite)
• THINK: What if the dendrites don’t have receptors for that neurotransmitter?
Any questions?
GROUP ACTIVITY
Main parts of the brain1. Cerebrum2. Diencephalon
a. Thalamusb. Hypothalamus
3. Brain Stema. Midbrainb. Ponsc. Medulla
Oblongata
4. Cerebellum
CerebrumLobes:• Frontal
– “voluntary motor”
• Parietal– “general sense”
• Temporal – “hear, smell”
• Occipital– “vision”
Basal Ganglia• “Regulate body
movement”
Diencephalon
• Thalamus–“Relay station”
• Hypothalamus–“Maintain
homeostasis”
Brain stem
• Midbrain• Pons• Medulla Oblongata–“Vital center”
Cerebellum
• “Little brain”• “Coordination &
prediction”–Notice:• Folia• Arbor vitae
Other special parts of the brain
• Limbic system–“emotion and behavior”
• Reticular formation–“sleep-wake”–“filter the noise”
• Basal ganglia–Parkinson’s disease
Meninges of the cns• Protection!
–3 layers!1. Pia mater2. Arachnoid mater3. Dura mater
–2 important spaces• Epidural space
(outside dura)• Subarachnoid
space–CSF
Spinal cord
• Spinal cavity• Connected to the
brain– Extends from foramen
magnum to L1
• Decussation• 3 Main functions of
spinal cord– Sensory pathway– Motor pathway– Reflexes
Spinal nerves
• Spinal nerves: 31 pairs– 8 cervical– 12 thoracic– 5 lumbar– 5 sacral– 1 coccygeal
• Plexus– Cervical plexus
• Dermatome – Skin
Cranial Nerves• CN I
– Olfactory Smell
• CN II– Optic Vision
• CN V– Trigeminal Sensory face
• CN VII– Facial Motor face
• CN VIII– Vestibulocochlear
Hearing and balance
• CN X– Vagus Major
parasympathetic nerve
Spinal reflexes
Effectors
• What Motor Neurons communicate with
1. Muscles (skeletal, smooth, cardiac)
2. Glands
Group activity