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Flashcards in 02 Central Nervous System Deck (61):
1

Inputs into the brain

Afferents (SENSORY)

Eg. Touch, pain & temperature, special senses: see, smell, hear, balance, taste

Perceive through INPUTS via receptors and transmit info to the brain via AP.

2

Outputs from the brain

Efferents (MOTOR)

Output comes from brain (cranial nerves) and reaches its targets through a peripheral nerve.

3

CNS consists of?

Brain
Spinal Cord

4

PNS consists of?

Spinal nerves
Cranial nerves
Ganglia

5

Rostral

Up

6

Caudal

Down

7

Superior

Top

8

Dorsal

Towards the back

9

Inferior

Bottom

10

Ventral

Towards the belly

11

Anterior

Head end

12

Posterior

Rear end

13

3 Planes or Orientation for the Brain?

Horizonal - Slice across
Coronal - Slice down x axis of superior brain
Sagittal - Slice down y axis of superior brain

14

Gray Matter

Consists of nerve cell bodies (Near outside edges of brain)

15

White Matter

Axons (Towards the center of the brain)
Mostly white cause myelin = fat = white

16

Where do fibre tracts travel?

Descending fibres - Cortex to spinal cord
Ascending fibres - Spinal cord to cortex
Crossing the midline - right hemisphere of the brain controls the left side of the body

17

Brainstem

Consists of: Midbrain, Pons and Cerebellum, Medulla
Ascending tracts
Descending tracts
Cranial nerve nuclei
Connections to and from the cerebellum
Intrinsic Systems (Reticular Formation)

18

Forebrain

Hemispheres
Deep Nuclei (Thalamus, Basal Ganglia, Limbic system)
Diencephalon (Thalamus, hypothalamus, subthalamus)

19

Thalamus

Deep nuclei in forebrain
Controls what information reaches the CORTEX
Consciousness

20

Basal Ganglia

Movement
Cortical output

21

Cerebellum

Movement
Prediction and Coordination of cortical output

22

Limbic System

Processing of Emotionality
Saliency filtering

23

3 Layers of the Eye?

Sclera
Uveal Tract - Blood supply
Retina

24

3 Compartments of the Eye?

Anterior Chamber
Vitreous Body
Posterior Chamber

25

Schlemm's canal

Where Aqueous Humour is constantly recycled so the fluid over the iris stays clear.

26

Aqueous Humour

Produced by Ciliary body

27

Glaucoma

Term describing ocular disorders

28

Rods

Contain Rhodopsin
Peripheral Retina
Night/Movement
Extremely sensitive to light
120mil Rods in Retina

29

Cones

Contain Iodopsin
Central Retina
Color & Focus
Visual Acuity
6mil Cones in Retina

Cones Central Color

30

Where does refraction occur?

Cornea and at the lens.
Refractive power of cornea is greater but lens can change its shape.

31

Central Fovea

Contains ONLY CONE receptors
Greatest Visual Acuity - interfering cell layers pushed aside and light falls directly on photoreceptors.

32

Optic Disc

Blind spot
Emerging retinal arteries
No photoreceptors

33

Dark Current (LIGHT OFF)

Constant release of GLUTAMATE by CONES.
Constant Depolarization
OFF Ganglion fires AP
ON Ganglion does NOT fire AP

34

"Light Current" (LIGHT ON)

LESS GLUTAMATE release due to hyperpolarized cone receptor by light.
Close channels.
OFF Ganglion does NOT fire AP
ON Ganglion fires AP

35

What is the visual pathway?

Left field projects to RIGHT cortex
Right field projects to LEFT cortex

36

Dorsal Stream

Tells SPATIAL vision: Where? How?

37

Ventral Stream

Tells OBJECT vision: What? (Recognition)

38

Extereoceptors

OUTER - Interact with world around us
Pain and Temperature
Discriminative Touch/Vibration

39

Proprioceptors

INNER
Join receptors
Golgi tendon organs - know force generated on a body part
Muscle spindle

40

Anterolateral System

Comprises of ALL FIBRES carrying {Pain & Temperature} from the spinal cord to the brainstem + thalamus.

41

Spinothalamic Tract

Comprises of ONLY the fibres projecting from the spinal cord to the thalamus.

42

01 {Pain & Temperature}

Anterolateral System: Spinothalamic Tract
( 1 ) Cell body in spinal ganglion crosses midline at level of spinal cord
Synapse with 2nd Order Neuron @ spinal cord (Posterior horn)
( 2 ) Fibres ascend the anterolateral system (Spinal cord > brainstem + thalamus) contralaterally
( 3 ) Fibres synapses + terminates at VPL of Thalamus
Neurons in thalamus project to Primary Somatosensory Cortex (Lateral) and 'Limbic system (Medial system)'

43

Medial System

Emotional response to pain - OUCH

44

Lateral System

Discriminative localization of pain - You know where the pain is. (Eg. Left toe)

45

02 (Discriminative Touch, Vibration, Pressure)

Posterior Column Medial Lemniscus Pathway
( 1 ) Cell body in spinal ganglion
( 2 ) Ascends in Posterior Column + Synapses with 2nd Order Neuron in Caudal Medulla + Crosses midline
( 3 ) Ascends to Thalamus contralaterally through Medial Lemniscus
( 4 ) Synapse in VPL of Thalamus with 3rd Order Neuron and then projects to Primary Somatosensory Cortex

46

03 (Proprioception)

Conscious proprioception - (Cortex)
Travels with the Posterior Column Medial Lemniscus System to the Thalamus > Cortex

Unconscious proprioception - (Cerebellum)
Travels through Spinocerebellar tract to Cerebellum
Enters spinal cord, ascends ipsilaterally and enters cerebellum on the same side (Some synapses along the way)

47

Why are synapses important?

Every synapse you can decide if you want to continue with this information or not.

48

What does the motor system control?

Limb movement
Posture
Core
Balance

49

Lateral Corticospinal Tract

Innervation of limbs
Skilled movement of extremeties

50

Anterior Corticospinal Tract

Innervation of proximal muscles
Postural adjustment
Stabilizes core

51

04 (Corticospinal Tract)

( 1 ) Primary Motor Cortex (Upper Motor Neuron UMN)- Where cell bodies are (SUPER LONG Axons: Brainstem to Caudal Medulla)
( 2 ) Lateral crosses over @ Medulla, Anterior stays on the same side and crosses @ Spinal Cord level
( 3 ) Synapses at Spinal Cord with Lower Motor Neuron (LMN) for Lateral and Anterior

Goes from UMN to LMN - no synapses.

52

What is the trend seen in somatotopic organization from cortex to spinal cord?

Important areas get more cortical space.

? not sure if this card is correct.

53

What does the motor system do?

Does more than just control of voluntary movements.
Compensates for balance (Vestibulospinal tracts)
Compensates for voluntary movement
Muscle tone - Readiness of a muscle. Couch potato vs olympic athlete in 100m dash - Y-neurones
Moves our eyes/head towards what interests us
Motor reflexes

54

Vestibulospinal Tract

Maintains balance, postural control, muscle tone, gravity

55

Reticulospinal Tract

Postural control, muscle tone

56

Tectospinal Tract

Directs eyes and head/neck to object of interest.

57

What are the 3 Lobes of the Cerebellum?

( 1 ) Flocculonodular Lobe (Vestibulocerebellum) - Trunk control and stability and tells us about gravity - deals with Vestibular information. [WORM]

( 2 ) Anterior Lobe (Spinocerebellum/Vermis) - Synergistic movements of extremeties [NEWT]

( 3 ) Posterior Love (Cerebrocerebellum) - Has most SA of neurons. - Coordination of intricate and complex movements, topographical representation of the extremities, areas for eye movement and speech (tongue mouth face etc).

58

What are the 3 Cerebellar Loops and their function?

Vestibulocerebellar connections
Spinocerebellar connections
Cerebrocerebellar connections

Allow:
- Coordinated, balanced and smooth movement
- Anticipation of movement
- Predictions that feedback to the cortex (Predicts movement of everything in field of vision)

59

What does the Cerebellum do?

Stickler for detail - Micro-manager
Coordinator and predictor of movement.

Balance - Linked to vestibular nuclei
Gait - Pattern of movement of the limbs
Receives and interprets proprioceptive information (Muscle tone, where my limbs are etc)
Fine Movements, Hand-Eye Coordination
Predicts sensory consequences of movement.
Information sent to cerebellum can be used for skilled manipulation of muscles and mental concepts.

60

Vestibular Information of the Cerebellum

Project from PARAVERMIS (next2vermis) to FLOCCULONODULAR lobe.

Provides information about the position of the head and body in space.
Helps orient eyes during locomotion.

61

Vestibulocerebellar Loop

?