Transcript Nervous system 1 - INAYA Medical College

Physiology
232 BMS
Dr/Nahla Yacout
2015/2016
 What is nervous system?
 Classification of nervous system
 Neurons
 What is neuron?
 Morphological classification of neurons
 Functional classification of neurons
 Parts of the brain & functions of each part
 Short notes on spinal cord, meninges, cerebrospinal fluid (CSF)
 Peripheral nervous system (PNS)
 It’s main function
 Types of nerves of PNS
 Autonomic ganglia, Synapse, Preganglionic neurons,
Postganglionic neurons
 Acetylcholine (Ach)
 Places of it’s release
 Ach receptors (Their actions, agonists & antagonists)
 Noradrenaline (NA)
 Places of it’s release
 NA receptors
 It’s actions
 Difference between sympathetic & parasympathetic systems &
their effects on organs
The nervous system is a complex network of nerves and cells
that carry messages to and from the brain and spinal cord to
various parts of the body.
Central
Peripheral
Brain Spinal cord Somatic Autonomic NS
NS
(Involuntary)
(Voluntary)
Sympathetic
Adrenergic system
NT: Noradrenaline
Parasympathetic
Cholinergic system
NT: Acetylcholine
 Is the most complicated organ in the body
 It has nerve cells called neurons (Neuron: is the basic unit in
the nervous system, it is a specialized conductor cell that
recieves & transmits nerve impulses(
These neurons consist of 4 regions:
 Dendrites: Are highly branched thick extensions that function
to carry nerve impulses into the cell body
 Cell body (Soma)
 Axon: It functions to carry impulses from the cell body to
another neuron or tissue
 Pre-synaptic terminals
Functional classification of neurons
 Sensory (Afferent) neurons: Carry impulses from different
organs to the brain
 Motor (Efferent) neurons: Carry impulses from the brain
 Interneurons (Association neurons): Connect sensory &
motor neurons
Brain
Forebrain
Midbrain
Hindbrain
Cerebrum
Tectum
Thalamus
Hypothalamus
Cerebellum
Tagmentum
Pons
MO
Cerebrum
Is the largest part of the brain
Divided into two hemispheres: Right & Left
hemispheres
Divided into 4 lobes: Frontal, Temporal,
Parietal, Occipital
Each hemisphere controls the activities of the
side of the body opposite that hemisphere
Thalamus
Important in regulating sleep & wakefullness
Hypothalamus
Is located below thalamus
It synthesizes & secretes certain
hormones which in turn stimulate or inhibit
the secretion of pituitary hormones
It controls body temperature, hunger,
thirst
Cerebellum
It plays an important role in motor
control
Medulla oblongata
It contains the cardiac, respiratory, &
vomitting centers & so it deals with the
involuntary actions of breathing, heart
rate & blood pressure
Spinal cord
 It is the main pathway for information connecting the brain &
peripheral nervous system
 It is shorter than the vertebral column
 The enclosing bony vertebral column protects the relatively
shorter spinal cord
 It consists of 31 nerve segments which are arranged from
above as 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, & 1
coccygeal
 A pair of spinal nerves comes out of each segment
Meninges
Are 3 membranes covering the brain & spinal cord acting as a
barrier to protect them against bacteria & other microorganisms
(Dura matter followed by Arachnoid & the innermost is the Pia
matter)
Is a fluid circulating around the brain & spinal cord. It protects &
nourishes them