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The S*" Grey's biology 5 The nervous system Second Peripheral nervous system ?? ?? Nelwork o it connects the central nervous system with all the body parts o It consists of a network of nerves that are distributed all over the different body parts & includes: (1). Cranial nerves o Number: 12 pairs connected to the brain o Types: sensory, motor or mixed nerves Mixed nerves They are nerves that transmit the nerve impulses from the receptor organs to the brain and transmit the stimulating orders from the brain to the effector organs "They are sensory and motor nerves together" (2).Ans EXI or n are SyS Re R system The reflex arc consists of In most cases Sense organ Sensory neuron connector neuron Motor neuron Efferent Responding organ Effector Receptor Afferent Intermediate It is the organ that responds to the changes that happened in the enviroment, such as muscles and glands.For Your Information o The vertebrae of the vertebral column 33 vertebrae) are arranged from up to down into five regions, which are:

• Cervical vertebrae
• Thoracic vertebrae (12)
• Lumbar vertebrae 5
• Sacral vertebrae (5)
• Coccygeal vertebrae (4) -> So, the number of nerves pairs is different from the number of vertebrae in cervical & coccygeal regions ??y?Spinal nerve Grey's biology 5 The nervous system o Types: mixed (sensory and motor nerves together) o Spinal nerves roots: each spinal nerve has two roots (dorsal and ventral.): P.O.C.

Ventral root Dorsal root It contains motor nerve fibers.stimulating motor orders (nerve impulses) that come from the brain and spinal cord to the responding (effector) organs, such as muscles and glands.Sensory neuron Connector neuron Sensory fiber Dorsal root Grey mamter Skin surface of thumb (Sensory receptors) (2) (1) (4) Motor fiber Ventral o the ????b. Involuntary (autonomic) reflex arc The response is in the involuntary muscles (like cardiac muscle) or glands.Reflex actions are of two types: a. Voluntary (somatic) reflex arc The response is in the voluntary (skeletal) muscles.Spinal nerves o Number: 31 pairs are connected to the spinal cord and exist in successive pairs on both sides of spinal cord and these pairs are arranged, as follows:

Nerve Number

Cervical 8 pairs that are connected with the neck.It transmits messages or Function It transmits messages (nerve impulses) from the receptor organs to the spinal cord and from it to the brain.Thoracic 12 pairs that are connected with the chest (thorax 4 Lumbar 5 pairs that are connected with the lumbar ????vertebrae

Sarcal 5 pairs that are connected with the sacral ?????Structure It contains sensory nerve fibers.coccygeal 1 pair that is connected with coccyx.vertebrae.???????3?(0).?

The S*"
Grey's biology
5
The nervous system
Second
Peripheral nervous system ال ال
Nelwork
• it connects the central nervous system with all the body parts
• It consists of a network of nerves that are distributed all over the different body parts & includes:
(1). Cranial nerves
• Number: 12 pairs connected to the brain
• Types: sensory, motor or mixed nerves
Mixed nerves
They are nerves that transmit the nerve impulses from the receptor organs to the brain and transmit the stimulating orders from the brain to the effector organs "They are sensory and motor nerves together"
(2). Spinal nerves
• Number: 31 pairs are connected to the spinal cord and exist in successive pairs on both sides of spinal cord and these pairs are arranged, as follows:

Nerve
Number

Cervical
8 pairs that are connected with the neck. عنقيه

Thoracic
12 pairs that are connected with the chest (thorax
4
Lumbar
5 pairs that are connected with the lumbar قطفي
vertebrae

Sarcal
5 pairs that are connected with the sacral عجزية
vertebrae.

coccygeal
1 pair that is connected with coccyx.
صد
Spinal nerve
Grey's biology
5
The nervous system
• Types: mixed (sensory and motor nerves together)
• Spinal nerves roots: each spinal nerve has two roots (dorsal and ventral.):
P.O.C.

Ventral root
Dorsal root
It contains motor nerve fibers.
Structure
It contains sensory nerve fibers.
It transmits messages or
Function
It transmits messages (nerve impulses) from the receptor organs to the spinal cord and from it to the brain.
stimulating motor orders (nerve impulses) that come from the brain and spinal cord to the responding (effector) organs, such as muscles and glands.
For Your Information
• The vertebrae of the vertebral column
33 vertebrae) are arranged from
up to down into five regions, which are:

• Cervical vertebrae


• Thoracic vertebrae (12)


• Lumbar vertebrae
  5


• Sacral vertebrae (5)


• Coccygeal vertebrae (4)
  → So, the number of nerves pairs is different from the number of vertebrae in cervical & coccygeal regions
  اوyء
  3回
  (0).
  Ans
  EXI
  or n are
  SyS
  Re
  R
  system
  The reflex arc consists of
  In most cases
  Sense organ
  Sensory neuron
  connector neuron
  Motor neuron
  Efferent
  Responding organ
  Effector
  Receptor
  Afferent
  Intermediate
  It is the organ that responds to the changes that happened in the enviroment, such as muscles and glands.
  Reflex actions are of two types:
  a. Voluntary (somatic) reflex arc
  The response is in the voluntary (skeletal) muscles.
  b. Involuntary (autonomic) reflex arc
  The response is in the involuntary muscles (like cardiac muscle) or glands.
  Sensory neuron
  Connector neuron
  Sensory fiber
  Dorsal root
  Grey
  mamter
  Skin surface of thumb (Sensory receptors)
  (2)
  (1)
  (4)
  Motor fiber
  Ventral
  • the
  اهاء ز
  ends
  Y0
  =
  •Motor
  White matter
  neuron
  → Receiral

connedo
Light candle
Muscles of arm
(Stimulus) (Responding organ "Effector")
BACER
Stimulus
Mechanism of the reflex action
SEFfereNT
(SensorY nerves (moor)
Nerve cell
130
Autonomic nervous system
• Function:
It regulates the different involuntary activities (that don't obey the human will) as:
(1). Regulating the contraction movement of the cardiac muscles & smooth (involuntary) muscles
(2). Secretion of the body glands
The autonomic nervous system consists of:
(1). Sympathetic nervous system:
• Its nerve fibers are arisen from the thoracic and lumbar regions of the spinal cord
• Function: It acts as the emergency system, where the nerve impulses that carried by this system control many of the internal body organs causing some changes to them that enable the body to face the emergency situations
(2). Parasympathetic nervous system:
• Its nerve fibers are arisen from the brain stem and sacral region of the spinal
• Most of the internal body parts receive nerve fibers from both the sympathetic and parasympathetic systems & in most cases the effect of one system antagonizes the effect of the other system, as shown in the following
system
hown in the k
reflex action so e
Autonomic
Effecter nervous organs system
Effect of sympathetic nervous system
Effect of
parasympathetic nervous system
stem
Eye :
Causes dilation of eye pupil.
Causes contraction of eye pupil.
Salivary glands:
Causes a decrease in the secretion of saliva.
Causes an increase in the secretion of saliva.
ties (that don.
Respiratory system:
Causes dilation (relaxation) of bronchioles and decreases their secretions.
Causes constriction (contraction) of bronchioles and increases their secretions.
diac muscles &~
Heart:
Increases the heartbeats rate and the force of contraction.
Decreases the
heartbeats rate and the force of contraction.
ts of:
Blood vessels :
Causes vasoconstriction (contraction) of blood vessels that are present in skin, viscera, salivary glands, brain, genital organs and lungs.
Causes vasodilation (relaxation) of blood vessels that are present in salivary glands and genital organs.
mbar regions ofte
Alimentary canal:
Causes relaxation of the wall of stomach, intestine and colon.
Causes contraction of the wall of stomach, intestine and colon.
Gastric glands :
Decreases the secretion.
Increases the secretion.
he nerve impulse
Pancreas :
Causes a decrease in the secretion of enzymes.
Causes an increase in the secretion of enzymes.
dy organs car; ergency situation
cral region do,
Liver :
Causes the breakdown of glycogen, therefore the glucose level in blood increases.
Causes Contraction of gallbladder → bile
twce
Medulla of the adrenal gland:
Vely

1. m.P
   Stimulates the secretion of adrenaline hormone (epinephrine) which
   increases the blood pressure, heartbeats rate and the glucose level in blood
   No parasympathetic fibers conhection with this gland.
   rom both the 75es the effer.
   Urinary bladder :
   Causes relaxation of urinary bladder.
   Causes contraction of urinary bladder.
   е
   &
   133
   Grey's biology
   • The nervous system
   ods
   For Your Information
   • The brain stem (Truncus encephali) consists of the midbrain, Pons Varolii & medulla oblongata
   Effects of sympathetic nervous system
   Dilation of
   Brain stem
   eye pupil
   Effects of parasympathetic nervous system
   Contraction of eye pupil
   Decrease the salivary glands secretion
   Dilation of bronchioles
   Increases the heart contraction
   Decreases the secretions
   Increases the glucose level in blood
   Epinephrine hormone secretion
   Relaxation of urinary bladder
   Cervical region
   Thoracic region
   Lumbar region
   Increase the salivary glands secretion
   slows down the heart contraction
   Contraction of bronchioles
   Increases the secretions
   Contraction of gall bladder
   Sacral region
   Different effects of autonomic nervous system on some parts of the body
   Contraction of urinary bladder
   Q1. Wh
   B). Thor (C). Lum
   Answer
   Explan and lumk
   are arise


2. Fro fbers t
   A). Sacr (B). Thor (C). Cerv
   D). Brai
   Answer Explan: the para
   drain ste
   134
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