Exam 2 Flashcards Preview

CNS > Exam 2 > Flashcards

Flashcards in Exam 2 Deck (45):
1

Arteries if the forebrian

Anterior cerebral artery---
Middle cerebral artery---- branches of the internal carotid artery
Posterior cerebral artery-- (Gets blood from vertebral artery too)

2

Anterior Cerebral Artery

Supplies most of the medial brain
Arches over the corpus callosum

3

Middle Cerebral Artery

Biggest of the 3
Receives 80% of the internal carotid blood flow
Located along the lateral fissure
2 branches: upper (frontal & parietal) and lower ( temporal & occipital)
Supplies blood to 2/3 of the lateral surface
Lateral striated arteries --> lesion pyramidal tract fibers @ internal capsule.

4

Posterior Cerebral Artery

25% of the blood flow comes from the internal carotid artery.
Other 75% comes from vertebral artery
Supplies occipital (medial part) and temporal (inferior part) lobes.

5

Blood supply to the brain
Vertebral Artery

Posterior inferior cerebellar artery- lateral side of the medulla
Anterior spinal artery- ventral and medial aspects of the medulla
Posterior spinal artery- dorsal and medial aspects of the medulla

6

Blood supply to the brain
Anterior Inferior Cerebellar Artery

Supplies the lateral sides of the pons and the inner ear ( artery it the inner ear, labyrinthine artery)

7

Blood supply to the brain
Pontine

Small and striated
Supplies midpons

8

Blood supply to the brain
Posterior Cerebral

Supplies the midbrain

9

Venous Drainage
Superficial

Superior brain-superior sagittal sinus
Middle brain-cavernous sinus
Inferior brain-transverse sinus

10

Venus Drainage
Deep

Great cerebral vein of Galen

11

Regulation of blood flow

Auto-regulation:
- H+ concentration
- intraluminar pressure

12

Meninges

Dura mater
Arachnoid membrane
Pia mater

Difference in brain and vertebral canal

13

Cranial dura

Two layers:
Periosteal layer-rich blood supply
Meningeal layer-no vascular supply
Potential space - located inbetween the two layers
Innervated by Trigeminal nerve c1-c3

14

Folds of the Meningeal layer

Falx Cerebri (longitudinal fissure)
Tentorium Cerebelli
Falx Cerebelli (separating the cerebellum)

15

Cranial arachnoid

Space between dura and arachnoid = subdural space
Arachnoid trabeculae suspends the brain in the CSF
Arachnoid cisterns (found near sinuses, pouches)

16

Arachnoid granulation

CSF passes through the sinuses (helps get ride of old CSF)

17

Cranial pia

Follows contours of the brain (right up against the brain! big space between arachnoid and pia)

18

Spinal dura

One layer
Epidural fat and a plexus of veins separates intro the vertebral periosteum.
Ends at S2
Coccygeal ligament ( filum terminale externa) anchors it to periosteum of cx1 and cx2

19

Spinal arachnoid

Potential subdural space
Trabeculae suspends the spinal cord
Lumbar cistern L2-S2 ( pouch, elongated roots, cauda equina found within

20

Spinal pia

Filum terminale
21 (pairs) denticulate ligaments attach to dura from foramen magnum to below tv12
Pia is tightly attached to spinal cord as it is in the brain
Extention-filum terminale interna, has pia and dura inside the dural sac, thicker.

21

Dural sinuses

Lined with endothelium
No valves
Collects blood from brain and emissary veins
Collects CSF from subarachnoid space
Drains into the internal jugular vein
Carry deoxygenated blood

22

Anterior inferior sinuses

Cavernous - sellar tursica,surround pituitary gland
Sphenoparietal - less wing of sphenoid bone
Superior petrosal
Inferior petrosal
Basilar plexus - lies along basic skull, clivous

23

Posterior superior sinuses

Superior sagittal
Inferior sagittal Both longitudinal fissure
Straight - runs bw tentorium falx Cerebelli
Transverse - runs in sigmoid sinus
Sigmoid
Confluence - all sinuses come together here, creating a whirlpool. Sucks the blood up by creating a vacuum.

24

Cerebral spinal fluid

Formed by the choroid plexus
- 14-35ml per hour
- 800 ml per day
- 150 ml at any given moment
High sodium, potassium, and chloride
Low in protein, lymphocytes, and epitheliod cells
Cushions the brain and removes waste products

25

Ventricles

Lateral ventricles (connected through 3rd ven. Through interventricular foramen. 4th bw pons and cerebellum connected to 3rd ven. Through cerebral aqueduct.
- anterior horn-frontal lobe
- posterior horn-occipital lobe
- body-parietal lobe
- inferior horn-temporal lobe
Interventricular foramen
3rd ventricle
Cerebral aqueduct
4th ventricle
Central canal

26

Sensory unit

Stem fiber (axon) and all of its endings (receptors)
Receptive field
- territory from which a sensory unit can be excited
- not the same as a dermatome!!

27

Dermatome

Strip of skin Innervated by a single spinal nerve
(Large amount of overlap by adjacent, small amount of overlap by non-adjacent, more neurons)

28

Sensory transduction

The transformation of a stimulus into an electrical signal

29

Rapid adapting receptors phasic

(Bursting) respond quickly and maximally
Will stop responding even when stimulus continues.

30

Slowly adapting receptors tonic

(Continuous) continue to respond to stimulus
Don't react as strongly as fast but stimulus is still there

31

Classification by source

Exteroceptor-stimuli from outside environment
Interoceptor-stimuli from internal environment
Proprioceptors- position sense (body position, tense on joints and muscles

32

Classification by function (modality)

Nociceptor - pain (noctious)
Thermoceptor - temperature
Mechanoceptor - "physical deformation"

33

Receptor types
No capsules

Free endings
- pain
- temperature
- SA (slow adapting)
Follicular ( wraps around follicule, responds to movement of hair)
- touch (hair)
- RA ( rapid adapting)
Merkel cell (hold on to something or pressure)
- edge detector
- SA
Specialized endothelial cells

34

Receptor types
Capsules

Encapsulated
- meissner's
RA
Ruffini's (deeper, responds to outside forces against you)
- shearing (drag)
- SA
Pacinian (largest receptor visible w/out magnification, deep, several layers of CT)
- vibration
- RA

35

Sensory inflammation of joints, muscles, and skin are...

Integrated in the parietal lobe ( major association of awareness)

36

The brain...

Comprises 2% of the entire body weight
Utilizes 20% of the body's O2
17% of the cardiac output goes there.

37

Reticular formation

Net of fibers
Phylogenetically old
- poorly organized
- survival

38

Cellular regions

Raphe (seam)
- midline (median) --> cells secret serotonin (5-HT)
Mangocellular/Gigntocellular (big/really big)
- paramedian - surrounding the Raphe
- central - center of 1/2 brainstem
- medial - center of 1/2 brainstem
Parvocellular (small)
- lateral

39

Neurotransmitter
Acetylcholine

motor system, excitatory
- influences movement
- peduncleopontine -> found here

40

Neurotransmitters
Noadrenergic/Norepinephrine

Awareness
- locus coeruleus -> found here
Nucleus of the solitary tract -> found in medulla, sensory area, viseral control
Ven trilateral medulla

41

Neurotransmitter
Dopamine

Motivation
Decision making
Ventral tegmental area -> found here
* precurserto norepinephrine

42

Neurotransmitter
Serotonin

Awareness/arousal
Mood
Decrease pain
Raphe nucleus -> found here

43

Goes everywhere, does everything

Afferent, efferent, autonomic, endocrine, awareness, biorhythms, motor, sensory, limbic, association

44

Functions

Levels of awareness
- ARAS (ascending reticular activation system)
> acoustic startle responses
> protects from injury by a predator
Modulate muscle tone
Respiration and cardiac rhythm
Pain suppression -> Raphe nucleus helps this
Emotion of pain (limbic)

45

Reticulospinal tract

Medullary -> lateral! movements of limbs
- reticulospinal tract
Pontine reticulospinal tract -> medial affect trunk
Affect motor neurons
* sensory comes in dorsal horn -> blocked by Raphe nucleus