exam 1 - nervous system

CNS = brain and spinal cord

PNS = all the nerves that exit from brain (cranial nerves) or spinal cord (spinal nerves)
-- responsible for all sensory and motor signaling!

tracks are axon bundles in the CNS
nerves are all the axon bundles in the PNS

1) visceral (focuses on whats going on in ur internal organs; nausea, gas, pain, etc)
2) somatic (focuses on whats happening everywhere else!)

1) visceral (output to smooth and cardiac muscle; all the involuntary responses!)
-- further divided into sympathetic and parasympathetic

2) somatic (output to skeletal muscle; so ur reflexes and ur voluntary motions)

NEURONS: control activities, process info
- excitable
- high metabolic rate
- extreme longevity
- nonmitotic

GLIAL CELLS: support and protect the neurons
- nonexcitable
- mitotic asf
- mop up excess K+ to support extracellular enviro; aid in recovery from injuries

FALSE! they can be pretty long, esp in the PNS when they have to travel through like half of ur body

showing the movement of an action potential down a neuron's axon, and across its synapse to the second cell (shown as a neuron here, but in the body it can also just be a muscle cell)

PNS: schwann cells that kinda live on the axon
CNS: oligodendracytes that live in between diffferent neurons

1) dura mater: super thick and fibrous layer! has 2 layers: periosteal and menigeal
2) arachnoid mater: loose-ish shrink wrap vibes! has little "legs" under it that create a space for cerebrospinal fluid
3) pia mater: tight shrink wrap! it's basically adhered to the structure beneath it

CSF lives there!

true!!

A- sulci
B - gyri
C- cerebrum
D- cerebellum
E - brain stem

gray matter is made of the cell bodies of all the neurons in the area
white matter is all the myelin covered axons of the neurons

frontal
parietal
occipital
temporal
insula

insula (deep lobe of brain)

like very specific parts of the brain do very specific things; like there's not rlly overlap

planning, coordinating and executing skeletal muscle movement;
controlling personality, cognition, decision making , planning, language functions

(this is the one that doesnt develop until ur 25 ...)

- found in frontal lobe
- aka the precentral gyrus
- controls skeletal muscle activity

(highlighted red here)

- found in frontal lobe
- plans and coordinates skeletal muscle activity (hence the "pre-motor")

* pre-motor is found before the primary motor cortex duhhh

(highlighted blue here)

interpretting sensory info (via the somatosensory cortex)

- found in parietal lobe
- aka the postcentral gyrus
- interprets sensory info

(highlighted blue here)

basically shows us how much the precentral/primary motor cortex and the postcentral/somatosensory cortex favor each part of ur body; the bigger the body part is, the more sensitive/controlled it is

olfactory and auditor info

receives and interprets visual input; interprets associated memories with visual input

- found in occipital lobe
- receives visual input

recieiving and interpretting taste

responsible for proprioception (where u are in space)

- control over autonomic nervous system and endocrine system
- nuclei in the hypothalamus control:
--- reg of body temp
--- control of emotional behavior
--- control of food and water intake (so hunger and thirst innit)

* regulatory asf!

collection of deep brain structures that regulate emotions, memories and emotional responses to sensory stimuli
-- includes amygdala and hippocampus
-- connects to reticular formation to coordinate physical responses to fear, emotion and memory (like tensing up, high BP, nausea, etc)

A)
- fear center!
- processes fear and coordinates appropriate nervous system response
- recognizes menacing facial expression

B)
- forms, consolidates and retrieves memories

- acts as a filter for somatosensory information
- directs sensory info to correct cerebrum location; also sends info ab where sensation is coming from
- can edit, amplify or diminish info depending on what's important in the moment
--- like, after u put on your clothes, you're not super aware of the sensation of them on your skin all day; you start to focus on other details despite that continuous sensory info

the thalamus

- start of the brain stem
- made up of individual nuceli with discrete functions
- many centers of control for limb, eye motor movements

- part of brain stem
- sensory and motor tracts that connect the brain to the spinal cord

- last part of brain stem; directly continuous with spinal cord
- all comm btwn brain and spinal cord involves tracts through the medulla!
- important role in cardiac and respiratory control

- major conduction pathway btwn brain and body
- continuous with brainstem
- extends from the foramen magnum of the skull to L1/L2
- ends in the cauda equina
- protected by bone, ligaments, meninges and CSF

1 - cervical
2- thoracis
3 - lumbar
4- sacral
5- coccygeal

A - anterior ramus (mixed, to trunk and limbs)
B - posterior ramus (mixed, to back muscles and skin)
C - spinal ganglion (sensory, cell bods)
D - posterior horn (sensory)
E - posterior root (sensory)
F - spinal nerve (mixed)
G - anterior root (motor)
H - anterior horn (motor)
I - lateral horn (autonomic; reflexive interneurons)

true!!!!! once you pass the roots, the pathways converge into one mixed spinal nerve
* think ab it: all parts of your body need to send sensory info and then recieve a motor response duh

dorsal/posterior root

ventral rami

* ventral bc it's from a limb, not ncessarily bc it's sensory info!

ventral horn

interneuron

it's a little bulb btwn the spinal nerve and dorsal root that contains sensory cell bodies!

in the gray matter of the spinal cord (central ofc)

- plexus literally means "braid"
- it's where branches of a spinal nerve will split, merge, split, merge and split again
- mostly done so a lot of nerves can get into a relatively tight space
- also it's like a little back up plan: if one nerve gets damaged at a more peripheral location, then it's still innervated by several diff sources more upstream
- big "named" nerves split off from the plexus to innervate muscles

it's like a little back up plan: if one nerve gets damaged at a more peripheral location, then it's still innervated by several diff sources more upstream

* in the pic, the cervical plexus is a junction of spinal nerves C1,2,3,4 -- for every peripheral nerve, there's a little innervation from each -- if one happens to get damaged, ur still gonna be innervated by smthn!

- forms from anterior rami C1-4, deep to sternocleidomastoid
- sensory innervation of the neck
- motor innervation of severeal local muscles
- most significant nerve = phrenic nerve (innervates the diaphragm!)

- forms from anterior rami C5-T1, deep to clavicle
- sensory and motor innervation of the axilla and arms
- significant nerves include: musculotaneous, median, radial, ulnar

- forms from anterior rami of L1-4 (with contributions from T12)
- embedded within the psoas muscle
- sensory and motor innervation to the abdominal wall muscles, ant and medial thigh muscles
- significant nerves: iliohypogastric, ilioinguinial, femoral, genitofemoral, obturator

- forms from anterior rami of L4-S4, is found embedded in psoas muscle
- sensory and motor innervation to the genitals, post thigh muscles, gluteals, and most of lower leg and foot
- significant nerves: sciatic, pudendal

gives u a map of which spinal nerves innervate what regions
-- dermatomes = sensory
-- myotomes = motor

* super useful bc they can help us figure out the causes of nervous injury (like it can help narrow down if it's more peripheral or central)

- there are 12 (CN1-12)
- innervate ur eyes and face bookie
- come directly from the brain!

1. olfactory
2. optic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
7. facial
8. vestibulocochlear
9. glossopharyngeal
10. vagus
11. accessory
12. hypoglossal