Download Nervous System Guided Notes

The Nervous System- Guided Notes
1. Functions:
a. Initiate/regulate movement of body parts
b. Regulate secretions from glands
c. Gather info from environment- pain, temp, pressure, CO2, O2
d. Maintain an approximate consciousness
e. Stimulate thirst, hunger, fear, range and sexual behaviors
2. How the System is Divided: CNS- brain and spinal cord, PNS- all peripheral nerves
3. Smaller Units:
a. Neuron- specialized cell
i. Axon- transmits signals long distances to other structures
ii. Dendrite- extensions of the neuron, receives from other nerves
iii. Schwann Cells- increase diameter, create myelin sheath, makes
nerves work faster- not all nerves have myelin sheath
4. 3 classifications of neurons:
a. Sensory- takes in signals and transmit to CNS, takes in light and sound, etc
b. Interneuron- signals from one neuron to another
c. Motor- move things- go to muscles or glands
5. Neuron Function:
a. Impulse = electrochemical signal that transmits along the length of the neuron
b. Resting= interior of the cell is more negatively charged than the extracellular
region
c. Polarization= used to describe the condition in which one region of a cell has
a different charge than the adjacent regions.
d. Reflex= does not require conscious thought, reflex arc is simplest unit in
nervous system
6. Brain Structure:
a. CNS
VS
PNS
b. Meninges- group of 3 membranes that wrap around the brain and spinal cord
c. Cerebrospinal Fluid- protects spinal cord and brain
7. Parts of the Brain- Function
a. Cerebrum- voluntary movement and thought
b. Cerebellum- balance and coordination
c. Brain Stem - controls functions to maintain life (blood pressure, HR, RR)
8. Cerebrum: Structure
a. White Matter- myelinated axons
b. Grey Matter- cell bodies
c. Diencephalon= thalamus, epithalamus, hypothalamus and third ventricle
d. Mesencephalon= cerebral peduncles and four colliculi – nerve fibers that
connect the spinal cord and brinstem to the cerebral hemispheres
e. Metencephalon= cerebellum (dorsal) and pons (ventral)
f. Myelencephalon= medulla oblongata – autonomic centers
9. Spinal Cord:
 Spinal cord is the second component of the CNS and links the CNS
and the PNS
 Extends from base of the brain thru canal formed by vertebrae
 White matter-outer region, myelinated nerves
 Grey matter- inner portion, cell bodies
10. Sensory Somatic and Autonomic Systems:
a. Autonomic: involuntary, controls internal environment of animal
i. Two divisions: sympathetic and parasympathetic systems
ii. Sympathetic= fight or flight
iii. Sympathetic stimulation- HR and BP increases
iv. Blood shift away from the skin and abdominal organs to muscles, brain
and heart.
v. Bronchi open to allow more air into the lungs
vi. Pupils dilate- all in prep for physical activity such as running from a
predator.
vii. Parasympathetic system- opposite effect of the sympathetic system
viii. Activation of the parasympathetic system slows HR and lowers BP
ix. Pupils constrict
x. Blood shifts back to the skin and abdominal organs
b. Sensory Somatic :Includes 12 pairs of cranial nerves
i. Cranial nerves enter the brain directly, not the spinal cord
ii. Spinal nerves, 36 pairs- nerves enter spinal cord at each vertebral
opening, dorsal and ventral branches.
iii. Dorsal and ventral branches join to create a mixed nerve
c. Enteric:
 Network of motor and sensory neurons in the GI tract and glands
 Influenced by parasympathetic and sympathetic systems
 **Functional without input from outside viscera
 Controls local events in GI tract
11. Tests and Terms:
a. Myelogram- dye injected into the spinal cord to check for damage, take a
radiograph
b. Nystagmus- eyes move back and forth quickly, uncontrolled
c. Ataxia- uncoordinated movement
d. Atrophy- shrinkage of muscle due to lack of use or nervous system
stimulation