Upload
vara-lakshmi
View
119
Download
0
Embed Size (px)
Citation preview
NERVOUS SYSTEM
T. Naga Varalakshmi,
Assistant Professor,Dept of
PharmacologyNirmala College
of Pharmacy, Guntur
1. Sensory input – gathering information· To monitor changes occurring inside
and outside the body (changes = stimuli)
2. Integration –· to process and interpret sensory input
and decide if action is needed.3. Motor output
· A response to integrated stimuli· The response activates muscles or
glands
Functions of the Nervous System
Classification of Nervous System
Neuron• Cells of the nervous system are called nerve cells or neurons which carry "messages" through an electrochemical process called Action Potential. • The human brain has about 100 billion neuron.• Dendrites receive signals.• The cell body integrates signals.• The axon transmits action potential. The myelin sheath makes the signal travel faster.• Synaptic terminals transmit signals.
Basic nerve cell and Synapse
T.S. of Nerve
Action Potential
Some Neurotransmitters
Neurotransmitter Location Some Functions
Acetylcholine Neuron-to-muscle synapse Activates muscles
Dopamine Mid-brain Control of movement
Epinephrine Sympathetic system Stress response
Serotonin Midbrain, pons, medulla Mood, sleep
Endorphins Brain, spine Mood, pain reduction
Nitric Oxide Brain Memory storage
Supporting Cells (Neuroglia or Glia)
CENTRAL NERVOUS SYSTEM
Parts of Brain
Meninges of brain
Divisions of the Brain
Major Division Subdivision Structures
Prosencephalon (Forebrain)
Telencephalon Neocortex; Basal Ganglia; Amygdala; Hippocampus; Lateral Ventricles
Diencephalon Thalamus; Hypothalamus; Epithalamus; Third Ventricle
Mesencephalon (Midbrain) Mesencephalon Tectum; Tegmentum; Cerebral Aqueduct
Rhombencephalon (Hindbrain)
Metencephalon Cerebellum; Pons; Fourth Ventricle
Myelencephalon Medulla Oblongata; Fourth Ventricle
Telencephalon
Diencephalon
Mesencephalon (Midbrain) Metencephalon
Myelencephalon
The subdivisions of the brain
CEREBRUM
The cerebrum is the largest portion of the brain, consists of 2 Cerebral hemispheres, which are connected by Corpus Callosum. The surface of the brain is marked by Gyri, Sulci, and Fissures. A thin layer of Gray matter, lines outside of the Cerebral cortex and contains 75% of the cell bodies in the nervous system. Beneath the cortex is the White matter made up of myelinated nerve fibers connecting the cell bodies of the cortex with the rest of the nervous system.
Lobes of the Brain
Functional Areas of the Cerebral Cortex
Thalamus and Hypothalamus
Basal Ganglia
Brain Function: Cerebral Lateralization
Primary Motor Cortex
Primary Somatosensory
Cortex
Association areas of brain
Brain StemIt consists of the
Midbrain, Pons Medulla oblongata
MIDBRAIN: Located between Diencephalon and Pons, Contains bundles of myelinated nerve fibers that
convey impulses to and from higher parts of the brain, and masses of gray matter that serve as reflex centers.
It is the main centre for auditory and visual reflexes.
PONS Lying between the midbrain and medulla oblongata, transmits impulses between the brain and spinal cord. It contains centers that regulate the rate and depth of breathing.MEDULLA OBLONGATA It transmits all ascending and descending impulses between the brain and spinal cord. It contain
Cardiac center that controls heart rate, Vasomotor center for blood pressure control, Respiratory center that works along with the
Pons, to control the rate and depth of breathing.
Brain Stem: Midbrain, Pons & Medulla
Major Functions
1. Sensory perception2. Voluntary control of movement3. Language4. Personality traits5. Sophisticated mental events, such as thinking memory, decision making, creativity, and self-consciousness
1. Inhibition of muscle tone2. Coordination of slow, sustained movements3. Suppression of useless patterns of movements1. Relay station for all synaptic input2. Crude awareness of sensation3. Some degree of consciousness4. Role in motor control
1. Regulation of many homeostatic functions, such as temperature control, thirst, urine output, and food intake2. Important link between nervous and endocrine systems3. Extensive involvement with emotion and basic behavioral patterns1. Maintenance of balance2. Enhancement of muscle tone3. Coordination and planning of skilled voluntary muscle activity
1. Origin of majority of peripheral cranial nerves2. Cardiovascular, respiratory, and digestive control centers3. Regulation of muscle reflexes involved with equilibrium and posture4. Reception and integration of all synaptic input from spinal cord; arousal and activation of cerebral cortex5. Role in sleep-wake cycle
Cerebral cortex
Basal nuclei
Thalamus
Hypothalamus
Cerebellum
Brain stem(midbrain, pons,and medulla)
Cerebellum The cerebellum is made up of two hemispheres connected by a vermis. A thin layer of gray matter called the cerebellar cortex lies outside a core of white matter. The cerebellum communicates with other parts of the CNS through cerebellar peduncles. Functions –
integrate sensory information about the position of body parts
Coordinates skeletal muscle activity Maintains posture.
SPINAL CORD
The spinal cord consists of 31segments, each of which gives rise to a pair of spinal nerves. Two deep longitudinal grooves (anterior median fissure and posterior median sulcus) divide the cord into right and left halves. White matter, made up of bundles of myelinated nerve fibers (nerve tracts), surrounds a butterfly-shaped core of gray matter . A central canal contains cerebrospinal fluid.
39
REFLEX ARC
To transmit impulses to and from the brain, Carrying sensory information to the brain are called ascending tracts; Descending tracts carry motor information from the brain.
Functions of the Spinal Cord
Peripheral Nervous System
PNS consists of
Cranial nerves
Spinal nerves
They arise from the CNS
and travel throughout the
body. PNS -- Somatic (voluntary
activities), Autonomic
(involuntary activities).
Cranial Nerves
Autonomic Nervous System
Parasympathetic Sympathetic Nervous System
Sympathetic system ready the body for
an emergency
Para Sympathetic system restores the
body for Homeostasis
Disorders of Nervous System1.Alzheimer’s Disease 2. Parkinson’s Disease3. Dementia4. Cerebral Hypoxia5. Multiple sclerosis6. Phenylketonuria7. Encephalitis8. Neuritis9. Spina bifida
10. Depression11.Psychosis12. Mania 13. Tumours14. Neuropathy15. Meningitis16. Stroke17.Hydrocephal
us etc