Physiology Lab #2 Flashcards
CNS vs PNS
CNS - Brain + Spinal Cord
PNS - After nerves/cranial nerves exit (exit out of brain/spinal cord)
Split of PNS
Splits inot the somatic and autonomic
Somatic - Sensory and msucles
Autonomic - Includes sympathetic + parasypathetic (Heart and sweat gland muscles)
Spinal Cord (Sagital view)
Can see the vertabral bodies + can see the split into the cranial/Thoracs/Lmbar nerves
Spinal cord ends at L1/L2
L5 ends at T12 thoracic vertabre
C7 or T12 = spinal level (not exiting vertabral body)
Whats surrounds the spinal cord
Spinal cord is surrounded by mengies (Dura + Archnoid + Piamoter)
- Drua = tough + where the spinal cord exits
Ventral roots in Spinal Cord
Ventral roots = come out of Ventral element
- Vental element (very thin) - often torn in lab or in autopsy (very hard to sampoke venral roots)
Dorsal Root Ganglia
Dorsal root ganglia = sits in intervertibral space
- Sits in the foraman between vertabretes - a little away from the spinal cord NOT right on top
Dorsal root = projects through the dorsal horn and synapse (projects through synapse with snsory or motor nuerons)
Grey matter, White matter, Sulci, Gyri
Superficial layer = see grey matter
gyri - high points - outpuchings
Suci - valleys - invaginatiions
Sulci/gyri = differentiates us with mice (mice have smooth brain)
Lisy ensepholphosy
Disease where the brain is smooth (lethal)
Dorsal root nerves
Dorsal root = sensory nerves –> merges with motor nuerons in the ventral roots
Motor nuerons = in ventral roots
Why have different views of the brain
Different views = show you different things
Example - cornal = see deep matter structures (Ex. see basal ganglia)
***Applies to reading scans - need to pay attention to the view of the scan
Reading MRI scans based on angle
Coronal section - Looking at person facing foward
- see pons
Sagital section - NOW pons looks dfferent compared to in coronal section
Axial - Looking at feet foward if you were to be by their feet (right side of image is the left side of the persons body)
Answering dfferent question depening on view
A - Ventral view - can see brainstem
B - BIG line in middle = central sulcus (seperates the two hemispheres)
- Can also see sinus
C - se the cerebelum
Brainstem + cranial nerves
The cranial nerves exit from the brainstem
Sinuses in brain
Carry venous blood
Sinuses = within the memgies
Subarchnoid veins = where the venous pools sit
Why remove 50 mL of CSF
If you have build up of fluid in the brain –> removing 50 mL provides tension relief
- 50 mL = high volume tap
Vs. 20 mL is used fro diagnostics (sample bacetria + cell count)
- If take 20 mL the fluid is replaced in one hour
Cerebrospinal Fluid (CSF)
Functions:
1. Cushions the brain and spinal cord
2. Supplies nurtiesnts to the brain
3. removes wate products that result from brain metabolsim
**Adults have 150 mL of CSF
**Up to 50 L can be draine dBUT typically drain 20 mL
**Normal raite of CSF production = 20mL/hou r
**Entir CSF is replaced every 7.5 hours
CSF replacement
CSF = associated with arterial and venous
Arterial. = push CSF to CSF space
Venous = Absorb CSF
***Get constant turnover of blood and CSF
What is found in CSF
CSF = contains biomarkers for nuerological disease
Glymfatic system
Gets waste away form the brain
- Lymphatic system of the brain
Sampleing CSF
Use lumbar puncture for sampling CSF
sampling CSF = important in diagnostics
Have an emerging role in development of biomarkers in CSF for disease and therputics
- Ex. Infection or mengitus or multiple sclerosis –> have biomarers of what is happening in the brain BUT can’t take out the brain for biopsy = use CSF
Does Lumbar tap affect spinal cord?
When put in needle for lumbar tap - the needle goes to C4 or L5 vertabret (below the spinal cord = won’t injure the spinal cord)
- There are nerve roots = could cause pain
CSF = windo into what is going on in brain or spinal cord
Grey Vs. White matter
Grey = where neurons sit
- Grey = split into motor nuerons and intervenous nuerons
White = Myelin (primarily form oligiodendricytes)
- has tracks of nuerons
Grey matter = surounded by white matter
B12 deficneicey
Involoves dorsal tracals and cortecus spinal tracks –> clincally develops pathology related to these abnormaloties
Imaging of White and grey matter
Can see diference in imaging - grey and white matter are different radiologicaly
Image -
1. White layer around top = fat layer within the skull
2. can see ventrical (has CSF - black part is CSF)
3. Thin grey around the gryi = Dura layer suroudning the brain
Spinal cord englargments
Spinal cord = has enlargments
Englargments = in cervical and lumbar areas
- Have englargments because these areas have nerves for arms = have many tracks/nuerons going to arms because hvae lots of motor nuerons and sensory axons in arms (cervical area) = have englargments (Same idea for lumbar areas)
Compared to thoracis - thin because just affecting intercaustal muscles = fewer muscles = less nerves
Sagital Section of spinal cord
Image 1
White = CSF
Small bone like on right = spinous process of vertabrete
Big bone on left = Vertabrete
Image 2 - CSF = dark
Axial Section of spinal cord
White = spinal cord
Left side = right side of pateint
Top = Ventral
Bottom = Dorsal
Lumbar part of spine
Can see the spinal cord end and nerves exit through intervertebral foraman
At end = have a series of nerves come out of spinal cord = caudual quina
Cadua Quina
Series of nerves coming out of spinal cord
Ventral root
Thing going towards the left
Spinal Reflex
Have the dorsal root ganglia –> then goes to dorsal neuron –> synapsse to internueron –> activates quadriceps muscles and inhibits hamstrng muscles = get relex
- hamstring = angtagonist muscle
***Considered afferent response
Major Pathway from CNS to PNS
- Motor pathways
- Sensory pathways
homoculous
Shows contromutions (amount of cortext) that inerculing relation region
See leg = medial aspect of hemisphere
Hand = large represnetation + face/tongue is large –> have a lot of cortext for these areas = allows fine motor movement
Legs = less fine movement = less neurons = smaller on humunculous
Motor pathways from CNS to PNS
From cortex to spinal motor neurons –> move muscles
- Have lateral corticospinal tract –> goes to synaspse on moto nueros –> goes to skelatal muscles
LOOK AT IMAGE
Sensory Pathways
- Dorsal Column system
- Spinothalamic tract
Dorsal Column system
Function
1. Sense fine touch
2. Periopersepction (know where you are in space)
Ex. B12 defeincey - can’t talk because you don’t know where the leg is n soace because B12 affects dorsal sensory oathway (IF pateints look at legs then they can wlak)