The Spinal Cord L2 Flashcards Preview

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Flashcards in The Spinal Cord L2 Deck (74):
1

What does each of a rats whiskers represent?

a barrel of nerve fibres
200microns across
very precise representation

2

What can decrease your chances of getting dementia?

knowing more languages

3

What areas of the brain are potentially effected in an aphasia?

Wernickes
Brocas
Arcuate Fasiculus
-as it is to do with a disorder of speech (associated with the brain)

4

Is the human brain symmetrical or asymmetrical?

symmetrical

5

What is the relationship between the two hemispheres?

Nearly but not entirely distinct
Closely related and Interact with one another

6

What is the difference in sizing on the Left and Right Hemispheres?

Areas larger (e.g. Wernicke's) on the Left side
(when looking at skull imprint) Lateral fissure is larger on the left hemisphere and lateral fissure is more acute on the right hemisphere

7

Where does your spinal cord extend?

Right down the middle of your vertebral column

8

What 5 things is your spinal cord protected by?

1. Vertebral column
2. Meninges + CSF in subarachnoid space
3. Cerebral Spinal Fluid
4. Fat
5. Connective Tissue

9

What is the protective function of the Vertebral column for the spinal cord?

Spine is made out of stacks of vertebrae (Bone and Little Cartilage)
Separated by the intervertebral discs
Intervertebral discs act as a Shock Absorber

10

What is the protective function of the Meninges for the spinal cord and brain?

Both spinal cord and brain
Spinal Cord (Spinal Meninges)
Brain (Cranial Meninges
Three Connective Tissue (CT) coverings the ENCIRCLE the spinal cord and brain
Pia Mater (inner layer) + Arachnoid Mater (middle layer) + Dura Mater (outer layer)
Subarachnoid space between the Meningeal membranes (Arachnoid and Pia Mater) contains CerebroSpinal Fluid (CSF), which SUSPENDS the central nervous Tissue. Provides a Shock absorbing and Hydraulic cushion in a Weightless environment

11

What is the protective function of CerebroSpinal Fluid (CSF) in the spinal cord?

Central Canal is filled with CSF
CSF is produced by the Choroid Plexus
Provides cushioning : Hydraulic cushioning role and Shock absorber to protect the spine
Also located in the subarachnoid space between the Meningeal membranes (Arachnoid and Pia Mater). Here it SUSPENDS the central nervous Tissue. Provides a Shock absorbing and Hydraulic cushion in a Weightless environment

12

What is the protective function of Cerebrospinal Fluid (CSF) in the brain?

Filled between the Meningeal membranes (Arachnoid and Pia Mater) is CerebroSpinal Fluid (CSF), which SUSPENDS the central nervous Tissue. Provides a Shock absorbing and Hydraulic cushion in a Weightless environment
Also located in ventricles and cerebro aqueduct

13

What are the 3 protective structures of the brain?

1. Skull
2. Meninges
3. CSF (cerebrospinal fluid)

14

How many spinal nerve pairs are there?

31

15

What are the Upper 8 spinal nerves caller?

Cervical spinal nerves
(neck)

16

What are the next 12 spinal nerves?

Thoracic spinal nerves
(lungs)

17

What are the first group of 5 spinal nerves?

Lumbar spinal nerves

18

What are the second group of 5 spinal nerves?

Sacral spinal nerves

19

What is the last pair of spinal nerves?

Coccygeal

20

What is the order of the 21 pairs of spinal nerves?

Cervical = 8x pairs
Thoracic = 12x pairs
Lumbar = 5x pairs
Sacral = 5x pairs
Coccygeal = 1x pair

21

What are spinal nerves?

The paths of communication between the spinal cord and a specific region of the body
Each pair of spinal nerves is said to arise from a spinal segment and is named according to the segment they're located in

22

What is the shape of the spinal cord?

roughly oval
Flattened anteriorly and posteriorly slightly

23

What are the roots below the spinal cord collectively named?

Horse's tail
Cauda equina

24

Where does the spinal cord terminate?

A conical structure called the Concus Medullaris ('cone') between first and second Lumbar bertebrae

25

What happens to the nerves below the Concus Medullaris?

Lumbar, Sacral and Coccygeal do not leave the vertebral column at the same level they exit

26

Where does the spinal cord extend?

Spinal cord extends From the Medulla Oblongata
To the Superior part of the 2nd Lumbar vertebrae

27

What is a dermatome?

Band or region of the body (innervated by one spinal nerve) one spinal nerve is related to
Nerve innervates skin at the level of the dermatome
Dermatome provides sensory input into the CNS via the Posterior Dorsal Roots of a pair of spinal nerves,
Dermatomes also provide sensory input into the CNS via the Trigeminal Nerve (V) (fifth cranial nerve)

28

How many dermatomes are there?

30

29

What is special about the first spinal nerve?

C1
Doesn't arise from/go to a dermatome/skin
Only carries Motor fibres (ventral root only)

30

What is the Trigeminal nerve?

(V)
Fifth cranial nerve
Provided sensory information into the CNS (alongside dermatomes)

31

What is the dermatome of T4 on the human body?

nipple

32

What is the dermatome of T10 on the human body?

Umbillical

33

What is the dermatome innervated by the Coccygeal spinal nerve in the human body?

wrapped around Anus

34

What is the main components of an individual spinal nerve?

Dorsal/afferent/Posterior root
+
Ventral/efferent/Anterior root

35

What are the sensations which come through the dorsal root?

1. Touch and Pressure -
2. Pain and Temperature
2x major sets of information conveyed from skin
Each has a different corresponding nerve fibre coming from dermatome INTO (taking input) the Central Nervous System (CNS)

36

What lies just beneath the skin?

Receptors of Specialised connective tissue
Nerve fibre is in the middle
When the receptor gets Depressed, the nerve gets activated

37

What are some important features of encapsulated receptors?

Pseudounipolar nuerons
Takes the Dorsal/posterior/Afferent root
Equal level of entry and exit of the spinal cord and dermatome
Receptor is depressed and nerve gets activated
Specialised connective tissue capsule with nerve beginning in the middle (ENcapsulated)
Receptor is highly specialised and located just underneath the skin
Encapsulated receptors are highly discriminative and precise, up to less than thorax and abdomen
Cell body is located in the Dorsal root ganglion (which is a swelled/enlarged area in the dorsal root containing all the cell bodies of nerves which convey sensation to the spinal cord)
Relatively thicker
Myelinated fibres, Schwann cells wrapped around
Impulses therefore travel faster (50ms-1) between the Nodes of Ranvier via saltatory conduction
Myelination = speed of conduction and insulation
Dermatome --> spinal cord --> 1 primary somatosensory cortex on opposite side of the brain
Sensory information conveys INTO the spinal cord (REFLEXES) and has 2x processes
1. 1x branch into the Cortex, Up into the brain (very important branch)
2. 1x branch into the gray matter(dendrites and cell bodies) of the dorsal/posterior horn of the spinal cord

38

What is a dorsal root ganglion?

a swelled/enlarged area in the dorsal root containing all the cell bodies of nerves which convey sensation to the spinal cord

39

What is the speed of conduction in an encapsulated receptor?

50ms-1
Due to:
Myelinated fibres, Schwann cells wrapped around
Impulses therefore travel faster (50ms-1) between the Nodes of Ranvier via saltatory conduction
Myelination = speed of conduction and insulation

40

What is the capsule of the encapsulated receptor like?

Equal level of entry and exit of the spinal cord and dermatome
Receptor is depressed and nerve gets activated
Specialised connective tissue capsule with nerve beginning in the middle (ENcapsulated)
Receptor is highly specialised and located just underneath the skin
Encapsulated receptors are highly discriminative and precise, up to less than thorax and abdomen

41

What is the type of encapsulated receptor called for the discriminative sensation of touch?

Meissner corpsucles

42

What is the type of encapsulated receptor called for the discriminative sensation of pressure?

Pacinian corpsucles

43

What is the precision of discriminative sensation of the encapsulated receptor?

less than

44

What is a pseudounipolar neuron?

an encapsulated receptor neuron which conducts discriminative sensation along the dorsal root

45

What are some important features of non-encapsulated receptors?

No capsule
Non discriminative sensations of Pain and temperature information
Pain: signals Noxious, tissue damaged conditions. Receptors called Nociceptors. In every tissue BUT the brain
Temperature:Thermal sensation detected in receptors called Thermoreceptors
Cannot pinpoint/localise pain and temperature sensations
Naked free nerve endings
Terminations of branches of nerve fibres
Bare dendrites (lack any structural specifications)
Terminates in the MOST DORSAL past of the gray dorsal horn in the spinal cord
Under the skin in dermis
Sensitive
Thinner
Non-myelinated
Less fast conduction
Conduction is in a continuous manner at 1ms-1 : No Schwann cells or nodes of ranvier
Sensation is Less specific regionally (regional sensation > Pinpointed/precise sensation)

46

What is the speed of conduction in an non-encapsulated receptor?

1ms-1
Due to:
Less fast conduction
Conduction is in a continuous manner at 1ms-1 : No Schwann cells or nodes of ranvier

47

What is the precision of non-discriminative sensation of the non-encapsulated receptor?

0.5cm

48

Where are terminations of the encapsulated receptor's neurons?

Sensory information conveys INTO the spinal cord (REFLEXES) and has 1x cell body and 2x processes/axon branch
Directly into spinal cord OR brain
1. 1x branch into the Cortex, Up into the brain (very important branch)
2. 1x branch into the gray matter(dendrites and cell bodies) of the dorsal/posterior horn of the spinal cord

49

Where are terminations of the non-encapsulated receptor's neurons?

1x cell body and 1x process/axon branch
Directly into Spinal cord only (no branch into brain)
Terminates in the MOST DORSAL part of the dorsal gray horn of the spinal cord

50

What are the main features of the dorsal/afferent/posterior root?

Contains ONLY sensory nerves - form a particular strop of dermatome
Conducts nerve impulses from Sensory receptors (encapsulated or non-encapsulated respectively) as an INput into the CNS (directly into spinal cord OR brain) on the Opposite side

51

What are the main features of the ventral/efferent/anterior root?

contains ONLY motor neurons
Lower Motor Neurons (LMN)
Conducts nerve impulses from CNS OUTput to Effector organs, muscles and cells on the opposite side To the brian

52

What forms a spinal nerve?

Dorsal root + Ventral root

53

What are some important features of peripheral nerves?

Cell bodies originate from the Ventral gray root/horn

54

What is another name for peripheral nerves?

LMNs
Lower Motor Neurons

55

What are some important features of peripheral nerves?

Peripheral nerve=LMNs
Ventral/efferent/anterior root
Cell bodies located/originate from the Anterior Ventral gray root/horn
Lower Motor Neurons (LMNs)
Very large neurons
Largest Neurons in the spine
Innervates muscles/organs/cells on the the opposite side to the brain
1 muscle can be innervated by 3-4 nerves
conveys information OUT (OUTput) to the skeletal muscles Anteriorly
Myelinated axon
Schwaan Cells (as is the Peripheral NS (PNS))
Fast saltatory conduction (50ms-1)
Fast conduction Aids SMOOTH and Co-ORDINATED muscle movement/contraction
upon activation to send the message of contraction to the skeletal muscle(anterior), the Peripheral nerve fires and releases ACh directly into the Synpatic junction which then quickly effects the Motor End plate

56

What is another name for peripheral nerves?

LMNs
Lower Motor Neurons

57

Where is the cell body of a encapsulated discriminative neuron located?

Dorsal Root Ganglion in the Dorsal root

58

Where is the cell body of an non-encapsulated non-discriminative neuron located?

Dorsal Root Ganglion in the Dorsal root

59

Where is the cell body of the LMN peripheral neuron located?

Anterior Ventral Gray horn

60

Are peripheral nerves large or small?

LMNs/peripheral nerves are Large

61

What is the speed of conduction in an LMN peripheral Neuron?

50ms-1
Due to:
Myelinated axon
Fast saltatory conduction (50ms-1)
Fast conduction Aids SMOOTH and Co-ORDINATED muscle movement/contraction
upon activation to send the message of contraction to the skeletal muscle(anterior), the Peripheral nerve fires and releases ACh directly into the synaptic junction which then quickly effects the Motor End plate

62

Why is myelination essential in the peripheral LMN in the ventral root?

Myelinated axon
Fast saltatory conduction (50ms-1)

Fast conduction Aids SMOOTH and Co-ORDINATED muscle movement/contraction
upon activation to send the message of contraction to the skeletal muscle, the Peripheral nerve fires and releases ACh directly into the Synaptic Junction which then quicly effects the Motor End plate

63

What is effector muscle/organ/cell innervation like?

Innervates muscles/organs/cells on the the opposite side to the brain
1 muscle can be innervated by 3-4 nerves

64

What are temperature receptors called?

Thermal sensation detected at receptors called Thermoreceptors

65

What are Pain receptors called?

Nociceptors
Noxious, tissue damaged conditions
Found in every tissue EXCEPT in the BRAIN

66

Which are the largest neurons in the spine?

Lower Motor Neurons

67

What is the synaptic junction?

the nerve endings are NOT in direct contact with the muscle, but instead has a synaptic junction, where the information is passed from nerve --> to (skeletal) muscle via a Neurotransmitter (ACh) Acetylcholine

68

Why is the spinal cord critical?

Gets information from the skin --> CNS
Send information out, Innervating muscles

69

What are 3x types of Spinal Cord injuries?

1. Quadriplegia
2. Paraplegia
3. Sensory Loss

70

What is Quadriplegia?

c1-c3 Cervical (neck) injuries results in Four Limbed Paralysis
Damage to the Spinal cord
Leads to Loss of Sensation(cannot feel) AND Loss of/Inability to Move Muscles (paralysis)

71

What is Paraplegia?

T1 - below (lower part of the body effected) (not cervical, anything Thoracic or below)
Usually results in complete OR Incomplete paralysis
affecting the Legs and possibly the Trunk but NOT affecting the arms
-dependant on the extent of the injury as to whether it is Complete OR partial lower paralysis
Damage to the Spinal Cord
Leads to Loss of Sensation (cannot feel) and Loss of/Inability to Move Muscles (paralysis)

72

What is Sensory Loss?

Complete Transection of the spinal cord means that the cord is SEVERED COMPLETELY from one side to another
- therefore CUTTING ALL sensory (AND motor) tracts/nerve pathways
Results in Loss of sensation ALTOGETHER, AND the Loss of Voluntary movement, BELOW the level of the transection
Damage to BOTH the Spinal CORD and damage to the Spinal Nerves

73

What is myelinated by Schwann cells?

PERIPHERAL nervous system have glia called Schwann cells
PNS
Lower- LMNs

74

What is myelinated by Oligodendrocytes?

CENTRAL nervous system have glia called Oligodendrocytes
CNS
Upper motor neurons- UMNs