CNS PART 1 Spinal cord

Question 1

nervous system definition

Answer 1

is collocation of anatomically and functionally interrelated structures which regulate and coordinate the activity of body

Question 2

DIF of CNS ?

Answer 2

its system that’s consist a hundred of billion of neurons and glial cells , glial cells
provide supportive and protective to the neurons to perform trophic function

Question 3

classification of Nervous system ?

Answer 3

1 - According to topographical and anatomical principles
1-1 CNS : Brain and spinal cord
1-2 PNS : sensory organs, glands smooth muscles ganglia , spinal nerve , plexus
2- According to function
2-1 Somatic : is response for innervation of skin and skeletal muscles
2-2 Autonomic : response for innervation o f internal organs and glands , vessels and sympathetic and parasympathetic

Question 4

What is the deferent between somatic and autonomic

Answer 4

Somatic its mean the body and we can control it voluntarily

Autonomic we cant control it and its un voluntarily

Question 5

what is the main function of CNS ?

Answer 5

– its the adaptation

Question 6

What is the functions of CNS ?

Answer 6

1 Recive the impulses from dendrite
2 transformation from receptor to cell body
3 anlazying the information
4 tranasformation from axon termnials to recptor of dendrite
5 effect of response
6 feed back of stamuli

Question 7

type of cells in CNS

Answer 7

1- Neurons
2-Supportive : Astrocytes , Schwann cells , oligodendrocytes

Question 8

What is the classification of neurons ?

Answer 8

1- according to shape : Pyramidal filiform ,fusiform
2-according to size : small , middle , long
3-according to cell body or number of process : unipolar ,bipolar , pesidounipolar , multipolar ( The deferent is the number of the process
Ex : unipolar 1 dendrite
Bipolar 2 dendrite
Multipolar 3 or more dendrite or more , the axon always 1

Question 9

What is the classification of neurons according to function ?

Answer 9

1-1 sensory (receptor ) which have sensory nerve ending and able to perceive stimuli from internal and external environment

2 effector (motor) whos axon terminals have the effector which transmit the nerve impulse to effector organ

3 associated ( intermediate ) which will be in the intermediate position in the reflex arc and transmit the information from afferent neurons to efferent one

Question 10

What is the types of nerve fibers ?

Answer 10

• We have 2 types
  1- Mylanetd sheeth : impulse move faster like jumping located in somatic
  and in the place of nodes of ranvier the mylanted layer is absent and short gaps is exist between glial cells
• the conduction of speed in the hick fiber 80-120 , middel 30-80m/s and thin 10-30
  2-Non mylanetd sheeth : impulses moving slower located in autonomic

Question 11

Classification of nerve ending according to function ?

Answer 11

They are 3
1 receptor : its the nerve ending of sensory neurons and its perceive stimuli from external and internal environment and transform the energy into nerve impulses
And they are
1-1 extra receptor : located in skin and mucosa of oral and nasal cavity and its responsible for pain and temperature
1-2 interreceptor : located in the wall of visceral gland and its reasonable for chemical and machinal stimuli
1-3 proprioreceptor : or deep receptor : located in the muscles and tendon , capsule joints responsible for pressure and vibration , tactical stimuli
1-4 special organs receptor they have special sensory receptor and located in visual , acoustic , vestibuli , olfactory , gustatory

2 Effector : its junction between axons of somatic or vegetative efferent neurons and tissue , its conducting nerve impulses from neurons to effector organ

3 synapsis or internural : its specialized monofunctional structure intended contact transsmition of nerve impulses from neuron to another neuron or from neuron to effector organ

Question 12

explain the synapsis DIF and classification

Answer 12

– synapsis or internoural : its specialized monofunctional structure intended contact transsmition of nerve impulses from neuron to another neuron or from neuron to effector organ

– classification according to localization :
Axon - somatic
Axon - axon
Axon - dendrites
– classification according to mechanism of nerve impulse :
Synapsis with chemicals
Synapsis with electrical transmission
Synapsis with mixed transmission

Question 13

DIF OF reflex and refex arc and Classification

Answer 13

DIF : is response reaction of the body to an extremal or internal stimuli
-reflex arc : its chain of neurons that form a shape of arc
— Classification :
1- unconditional : its congenital ( genetic ) reactions of the body with participation of spinal cord and brain stem EX: withdrawing of hand upon prickling
2-Conditional : they are produce only with participation of cerebral cortex
EX: execrating enzymes of Stomach

Question 14

What is the ganglion ?

Answer 14

It is group of cell body do the same function and its located out of CNS

Question 15

what is the nucleus

Answer 15

It is group of cell body do the same function and its located in of CNS

Question 16

Emberoulogy of nervous system ?

Answer 16

Its start from the embrouinc layer
They are
-ectodorm
-mesodorm
-endodrom
- The nervous system formed by Ectoderm
Then some part of ectoderm cells start perphrate and crest a thick layer thin its from the first thing in nervous system which is the neural plate , then continue to perphrate and create neural groove by going down deeper then the margin of the neural groove goes medially and connect with each other and form the neural tube , then at the 5th week the neural tube form in his anterior section the brain and its from the ventricles of the brain and rest of the neural tube will be the spinal cord also its form the central canal

Question 17

explain extrenal the spinal cord

Answer 17

– Spinal cord or medulla spinals its think walled tube slightly flattened from front to back Its inside the vertebral canal at the level of the Atlantic arch
Start from medulla oblongata contend to L1 or L2 and its end by medullary cone
filum terminals descend to be attached to periosteum of 2nd coccygeal

–External structure of the spinal cord
The anterior surface its transversd by deep ant median fissure
And the post surface there is the post median sulcus and its dividing the post part into 2 half’s each half lateral surface carries anterolateral sulcus situated laterally to antemedian fissure and Postalatral sulcus situated lateral to post median sulcus
The anterolateral and posterolateral sulci there is root if the spinal nerves passing through , Posterior root represent the sensory ganglion
The ant root and peripheral process of peseduniporal neuron join immediately after the ganglion to form the trunk of the spinal nerve
Ant and post root they are at the same level of horizontal plan

Question 18

How many root we have ?

Answer 18

124 root
62 post
62 ant

Question 19

explain the segments of spinal cord

Answer 19

— Its transeversd section of spinal cord where is 2 pairs of roots Aries 2 dorsal and 2 ventral we have
-124 root : 62 post 62 ant
We have 31 pair
8 cervical
12 thoracic
5 lumber
5 sacral
1 coccygeal

Question 20

Skelatopy of the spinal cord

Answer 20

C1 - C4. C1 -C4
C5 - th1. C7 - th3
Th5 - th8. Th4 - th6
Th9 - th12. Th7 - th9
L1 - L5. Th10 -th12
S1-s5-co1. Th12 -L1-L2

Question 21

What is the trunks of the spinal cord ?

Answer 21

-Ventral root (ant) start from ant lateral sulcus
-Dorsal root ( post) start from postltral sulcus
-Peripheral process of psedunipolar neuron

Question 22

Internal structure of the spinal cord

Answer 22

Its formed by gray matter and white matter
- gray matter : butterfly shape formed mainly of neuron’s bodies and its gray bc the unmylnted sheeth
-what matter totally formed by axons and its white bc its the mylanted sheeth
-Its develop into 2 horns (ant - post )
From c1 to c7
And from c8 to L3 there is projection comes called the lateral horn
-between the ant and post horn there is central canal
— Talk about post horn :
Its narrow and long
On the lateral surface of the post horn there is no boundaries between the gray matter and white matter here is the gray matter and white matter mixed together and its small area called spinal reticular formation
Its appear more upper in the spinal cord near medulla oblongata , its very clear visible in cervical section and not much clear in thoracic section and its disappear in lumber section
-its consists of 3 nuclei
1-substintia gelatinosa
2-zona spongiosa
3-zona terminalis
—Talk about ant horn
Its bright , wider and short , its consist of 6 nuclei
1-anteriomedial
2-postromedial
3-antiroir
4-antrolatral
5-postalatral
6-central nuclei

Question 23

explain the meninges

Answer 23

-Its the coverings of the spinal cord Mainly they are 3
Dura matter , arachnoid matter. Pia matter
- 1 Dura matter : Its the outer most formed by connective tissue and works for protective function
- 2 Arachnoid matter: Its between the dura matter and pia matter its have some structure called ( denticulate ligament) attached to vertebral canal and vertebral body And they are for fixation of the spinal cord
- 3 Pia matter : Its the inner most and its rich of vessels and its function to supply the spinal cord
—— spaces of the meninges
1 Epidural space
2 Dura matter
3 sub Dural space : contain little of the cerbro fluid
4 arachnoid matter
5 sub arachnoid space : contain the crebro spinal fluid
6 pia matter

Question 24

explain the funiculus

Answer 24

–They are formed by process and they joined each other to form conducting tract
white matter divided into 3 funiculus :
Ant funiculus post funiculus Lateral funiculus

1-Ant funiculus : Its bounded by ant lateral sulcus and ant median sulcus and usually descending tract pass
1-1 tacto spinal tract
1-2 ant corticospinal tract
1-3 retculospinal tract
1-4 ant thalamicspinal tract
1-5 vestbual spinal tract
1-6 medial longetudinal fisculus
1-7 ant fasculus propruis

2-post funiculus :Mainly ascending tract pass though it Its bounded by post median fissure and post lateral sulcus
1 garciel. Fusculs
2 cunet fusculus
3 post fusculs
4 zona redeclares

3- Lateral funiculus : 1
post spino cerbral tract
2 ant spino crebral tract
3 latral spinothlamic tract
4 latral cotruco spinal tract
5 rubrospainal tract
6 olivo spinal tract
7 spino tactecal tract
8 latral fesculus

Question 25

how we distinguish the anatomical position of spinal cord ?

Answer 25

—we have two ways
1– the difference between the ant fissure and post sulcus
2- through the gray matter and its horns the ant horn is wide and short the post horn is long and narrow

Question 26

draw the Reflex arc simple and complex

Answer 26

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