Nervous system - Oct 2023.pdf body nervous

Nervous
Module
Degree based

1. The Nervous System

© Dendrites
N と Y

2. 

3. Peripheral nervous system

Somatic
sensory
division division

Sympathetic
division

Somatic
motor
division

Parasy mpathetic
vision

4. LS OF THE NERVOUS 1

ere are two cells of the nervous
ystem. These are;
vy Neuron
y Neuroglia
OThe functional unit of the nervous
system is the nerve cell, or neuron wé

se

euroglia or glial are supportive cells i
the nervous system that aid the functi
of neurons

5. STRUCTURE OF A NEURON

に ここ と D ーー
と

6. LASSIFICATION OF NEURONS).

urons may be classified according
structure or function.

Function Structure

・ Sensory (afferent) Unipolar ReurOns,
neuron ・ Bipolar _
ㆍ Interneuron ・ Multipolar

(association) neurons

。 Motor neuron ・ Anaxonic 3

7. STRUCTURAL CLASSIFICATION

Acn

Anaxonk neuron
Unipolar neuron

8. Peripheral nervous system Central nervous system

D Sensory (afferent)
neurons conduct
signals trom receptors
to the CNS.

=—>

@ Intemeurons

Motor (efferent) (association,

neurons conduct
fü

signals from the CNS confined to

to effectors such as

muscles and glands.

9. UROGLIA (Glia) _

ere are six types of supportive cells

OFour occur in the CNS
y Oligodendrocytes
y Ependymal cells
Y Microglia
y Astrocytes
o occur in the PNS
v Schwann cells (Neurilemmocytes)
y Satellite cells

10. 

11. SYNAPTIC TRANSMISSIO

e meeting point between a neuron

d any other cell is called a synapse

OThe synapses b/t neurons and skeletal
muscle cells are referred to as A
myoneural or neuromuscular À
junction we

OSynapse can be;

y Chemical synapse

y Electrical synapse +

12. 

13. CNS consists of the brain
d spinal cord

OCNS protected by a cranium
surrounding the brain

Overtebral column surrounding
the spinal cord

OThe CNS is bathed in

ebrospinal fluid

The CNS is composed of gray

and white matter

E NTRAL NERVOUS 2

14. THE BRAIN “oe

brain is semi-spherical but soft delicate
plex organ.

is the center for control and integration
© An adult brain weighs near 1.5 kg (3-3.5lbs)
© Averages about 1,600 g (3.5 Ib) in men

© 1,450 g in women

O Composed of an estimated 100 billion (1011)
neurons

© Anatomically, the brain is divided into 3 region;

Midbrain
© Hindbrain

15. | Cerebrum —
FOREBRAIN< Thalamus …

Hypothalamus ~

Pituitary gland

^
MIDBRAIN —
-一
Pons 一

HINDBRAIN | Medulla ——
See! a Spinal cord
Cerebellum —

16. Forebrain

a Telencephalon
A Diencephalon

Midbrain
__+— Mesencephalon

Hindbrain
Metencephalon
Myelencephalon

17. MENINGES OF THE ‘ae
ni NERVOUS SYSTEM

CNS is protected by
three connective tissue
membranes coverings
called meninges

OFrom superficial to deep

they are;
ra mater,
Arachnoid mater,

OPia mater

18. OThe brain is lined by 1
1160 meninges.

he brain is conspicuously marked

by surface gyri (folds) and sulci

(grooves).

OThe human brain is composed of
neurons, glial cells and blood
vessels.

Olt also consists of four internal,
terconnected chambers called
ventricles.

ye

19. Corebrar

Lateral sulcus-#

FA — Spina! cons

Longtuanal fissure

(a) Superior view (0) Lateral view

20. REBRAIN 9%

brain consist of the following regions; Telecephal
brum) and Diencephalon (Thalamus, hypothalamu: Es
alamus and pituitary gland)

“+ CEREBRUM
O The cerebrum is the largest part of the brain.

O It is divided into two hemispheres separated by the
longitudinal fissure.

o ne IS are prominently marked with gyri 2070
sulci.

ions of the two hemispheres are connected internally

e corpus callosum
Each cerebral hemisphere is subdivided by deep sulci
fissures, into the five lobes: Frontal, Parietal, Occi

Temporal and Insula

21. 

22. Parietal lobe Finkel liebe

Temporal lobe

23. DIENCEPHALON

ajor autonomic region of the brain that consists of vital
uctures such as;

halamus, Hypothalamus , Epithalamus , Pituitary
gland

© completely surrounded by the cerebral hemisphere of the
telencephalon. a

O These structures surround the third ventricle of the brain _
© The thalamus is a large ovoid mass of gray matter

© The hypothalamus is a small portion of the diencephalon
inferior to the thalamus

e epithalamus is the dorsal portion of the diencephalon
at includes a thin roof over the third ventricle.

© The pituitary gland, or hypophysis, is positioned on the
inferior aspect of the diencephalon

24. MIDBRAIN “oe

e midbrain is a short section of the
ain stem between the diencephalon
and the pons

©A short segment of the brainstem that
connects the hindbrain and forebrain

OWithin the midbrain is the cerebral vé
aqueduct (aqueduct of Sylvius)

includes important centers for
vision, hearing, pain, and motor
control

25. A Sg

Superior calculos

A
+ Meda geniculate nuctous

A

Aw

Anterior

~

Oouamaa nerve nn

Contras gay mater
Osama nucleus
Meda eemacus
Rad nudeus

26. HINDBRAIN qe
o embryonic hindbrain nao into two

divisions the metencephalon a
lencephalon

he metencephalon is the most superior portion
of the hindbrain.

O The pons which measures about 2.5 cm long,
forms a broad anterior bulge in the brainstem
just rostral to the medulla. 5

O It conducts signals up and down the brains
and between the brainstem and cerebellum

e cerebellum is the largest part of the
dbrain and receives most of its input by way
of the pons. Ye

O Occupies the inferior and posterior aspect of
the cranial cavity

27. Diencephalon:
Tram
Inn
Mammiary body ae

Cranal rerves

ーー (ff
> opec nerve (m
en cuomotor nerve (it)

à Trochiear nerve (IV)

Thigernnal nerve (の

Bi tocar rr vn

Facial nerve (Vit)

Patti ro

ーーーー Gossoptaryngeal nerve (DO
E Vagos nerve 09)

Meduila oblongata: EEE. 0
Prrama Hypogiossal nerve (Xi!)
Antenor median tsaure
Pyramidal decussaton
Spinal nerves

Spnai cord

(a) Ventral view

28. MYELENCEPHALON

OMyelencephalon
contain the s
medulla oblongata us

OThe medulla
oblongata is a
bulbous structure
about 3 cm (1In) Ke
long 、

OExternally, the

medulla resembles
the spinal cord

29. CEREBROSPINAL FLUID $
ENTRICLES OF THE BRAIN

e brain has four internal chamber calle
ntricles

“Two lateral ventricles

yA third and fourth ventricles

©The fourth ventricle is located in the brain.
stem

OThe cerebral aqueduct (aqueduct of
10145) passes through the midbrain to

nk the third and fourth ventricles.
© CSF is a clear fluid that forms a protective of

cushion around and within the CNS

30. Lateral voréricies
irterventnauiar
foramen

Thrd ventricle

Cerebral
aqueduct

Fou ventrcio

Lateral aperture

Medan apense

Contra! canal 一

Cereteum
lateral er

Interverenauar
foramen

Tha verercie

Corotras
aqueduct

Fourth ventricle

Lateral aperture

Medan aperture

31. SPINAL CORD “oe

is an elongated cylindrical structure that is a
elike bundle of nervous tissue

adults, it averages about 1.8 cm thick and 45
cm long

O It begins as a continuation of the medulla
oblongata at the level of the foramen magnum

O The spinal cord serves three principal functions:
Conduction, Locomotion and Reflexes
Y

O The cord gives rise to 31 pairs of spinal

nerves. the part supplied by each pair of spin:
nerves is called a segment.

e spinal cord is divided into cervical,
thoracic, lumbar, and sacral regions.

32. 

33. ROSS-SECTIONAL ANATOMY

e spinal cord consists of two kinds of
rvous tissue called gray and white
matter.

©Gray matter has a relatively dull color
because it contains little myelin. ~

Olt has butterfly- or H-shaped in cross ]

sections

O It contains the somas, dendrites, and
oximal parts of the axons of neurons.

Olt is the site of synaptic contact between, 4
neurons (information processing)

34. Posterior funiculus
White — Anterior funiculus
Lateral funicutus

columns |

Dorsal root

Ventral root

Posterior median sulcus
Gray commissure
Dorsal (posterior) horn
Ventral (anterior) horn
Lateral horn

Gray
matter

35. OWhite matter contains an abundance of 고이
ons, which give it a bright, pearly white

earance.

is composed of bundles of axons called tracts or
fascicule

Olt carry signals from one part of the CNS to another.

%

© Ascending tracts carry sensory information up the

rd and descending tracts conduct motor \

O The spinal cord has two tracts; Ascending and
descending tract

impulses down

36. Ascending
tracts
Dorsal column:

Gracie fascioulus 一 一 —
Cuneate fasccuus ーーーーーーー へ 、

Dorsal spinocerebellar tract

Ventral spinocerebellar tract 一 一

Anterolateral system 一
(containing

spinothalamic

and spinoreticular

tracts)

Ventral comreosp nal tract

Lateral
corticospinal tract

Lateral reticulospinal tract

Tectospinal tract

— Medal vestibulospinal tract

37. PERIPHERAL NERVOUS SYSTEM

OThe (PNS) is that portion of
the nervous system outside
the central nervous system

O Sensory receptors within the
sensory organs, neurons,
nerve, ganglia, and plexuses
are all part of the PNS

OThe nerves of the PNS are
classified as;
- cranial nerves or spinal nerves,

38. GENERAL ANATOMY Où .:
NERVES AND GANGLIA

nerve is a cordlike organ composed of
numerous nerve fibers (axons) bound together
by connective tissue.

ONerve fibers of the peripheral nervous system.
are ensheathed in Schwann cells, which form
neurilemma and often a myelin sheath around

e axon. Nerves has:

© endoneurium, perineurium and … 4

39. à Axon
ん — Myelin sheath
~

Endoneurium

Perineurium
Epineurium ss

Fascicle

Blood
vessels

40. CRANIAL NERVES “ae

‘anial nerves are nerves that emerge directly
m the brain and the brainstem.

OThere are 12 pairs of cranial nerves, numbered I
to XII 4

ュ

の They relay information between the brain and 。
parts of the body.

© Considers to be parts of both CNS and PNS %

ey are traditionally classified as sensory,
motor or mixed base on their functions.

41. 

42. Function

| Olfactory Sense of smell

| Optic Vision |
| Oculomotor — Motor control of some eye muscles and eyelid |
| Trochlear Motor control of some eye muscles 上

Iv | Trigeminal | Chewing muscles and some facial sensation -

| Vi | Abducent Motor control of some eye muscles

Motor control of facial muscles, salivation. Taste and

cutaneous sensations.

tic

| Glossopharyngeal | Salivation, sensations of skin, taste and viscera

nsation from th

Motor control of the heart and viscera,

thorax, pharynx and abdominal viscera

43. SPINAL NERVES 0

ere are 31 pairs of spinal nerves: 8 cervic
1-C8), 12 thoracic (T1-T12), 5 lumbar
1-L5), 5 sacral (S1-S5), and 1 coccygeal
(Co).

O The first cervical nerve emerges between the
skull and atlas

©The others emerge through intervertebral
ramina, including the anterior and posterior
foramina of the sacrum and the sacral +

44. Cervical phe num (01-09)

no.

9 The Spina! Nerve Roots and Plenusen. Postenor nem

45. AUTONOMIC NERVOUS — E
(ANS)

S is motor nervous system that controls
nds, cardiac muscle, and smooth muscle

O The primary target organs of the ANS are the
viscera of the thoracic and abdominal cav

O Its job is to regulate such fundamental U
and life processes as heart rate, blood
essure, body temperature, respirato
airflow, pupillary diameter, digestion,

energy metabolism, defecation, and ye
urinatian

46. DIVISION OF THE 3

e ANS has two subsystems

Sympathetic

© parasympathetic divisions

OSympathetic (Thoracolumbar) Division
The sympathetic division is also called e

thoracolumbar division

has relatively short preganglionic and
ong postganglionic fibers

47. RASYMPATHETIC >

e parasympathetic division is also
lled the craniosacral

Somas of the preganglionic neurons are
located in the pons, medulla oblongata,
and segments S2 to S4 of the spinal cord

OThe parasympathetic division has long
preganglionic fibers reaching almost all

the way to the target cells

hort postganglionic fibers that cover
rest of the distance.

48. Reflex Arc

Dorsal root

ganglion
Sin \

Peripheral
Sensor ve Process / Ist fore

Semitendinosus
antagonist muscle

Lateral horn
A ! Anterior
Ventral root Motor neuron hom

49. Rest and digest response

After th event dis

Blood Is directed towards

extremities = and breathing
+ Senses heighten
+ Focus narrows Pupils constrict
+ Digestion temporarily shuts down Digestion and saliva production
+ Cortisol is released, and we are increase

ready to either fight or run away Calmness and broader focus set in

50. 

51. Parasympathetic Nervous System

ALM
(Gas PARASYMPATHETIC

PUPILS SHRINK

SLOW, DEEP
BREATHS

HEART SLOWS

GUT ACTIVE

52. Difference Between

UNMYELINA?
Myelii

Myelinated & Unmyelinated Nerves,
Myelinated Unmyelinated Nerves.

Axons - Larger Axons - Smaller
Diameter Diameter
Axon -Surrounded Axon Surrounded by
by concentric cytoplasm of Schwann
layers of Schwann cell.
cell plasma
The speed of the membrane
transmission of the nerve Salutatory Salutatory conduction
conduction - ~ absent
present
een Density ofvoltage Density ofvoltage
Trade most parioben gated Nachannels- gated Na channels -
nerves > cel o more Less.
athetic
> Energy Energy consumption
peripheral nervous system Garmin ‘is us
nee Example - all Example - all
Short e fibers are Preganglionic Preganglionic fibres
fibres in ANS, in in ANS, in PNS fibres
ーー に PNS fibres more less than 1 um in
Can lose the nerv e than 1 um in diameter
wm conduct diameter

impulses is high

nerve fibers 4