CENTRAL & PERIPHERAL NERVOUS SYSTEMS

Slides:



Advertisements
Similar presentations
The Nervous System (Pgs )
Advertisements

The Nervous System.
Lab Activity 15 The Brain Portland Community College BI 232.
Nervous System Outline
Principles of Health Science There are two main divisions of the nervous system: The Central Nervous System The Peripheral Nervous System Divisions.
Coverings of the CNS 1) Bone – Cranium, Vertebrae 2) Meninges – Three connective tissue membranes covering the brain and spinal cord a) Dura Mater – outermost,
Chapter 9.  Central Nervous System (CNS)  Brain and spinal cord  Peripheral Nervous System (PNS) ◦ nerves.
The Nervous System Charles C. Cook, MD.
Chapter 8 Nervous System I
Central Nervous System Divisions of the Brain –Brain Stem Mesencephalon (Midbrain): Processes visual and auditory info and reflexes triggered by these.
The Brain. Divisions Cerebrum Diencephalon Brainstem Cerebellum.
The Central Nervous System
Nervous System. 6/3/2016Nervous System2 Functions Coordinates all of the activities of the body. Enables the body to respond and adapt to changes both.
Portland Community College
Essentials of Anatomy and Physiology Fifth edition Seeley, Stephens and Tate Slide 2.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin.
Central Nervous System
Nervous System Use your gray matter!. Central Nervous System Communication and coordination system of the body Seat of intellect and reasoning Consists.
ELAINE N. MARIEB EIGHTH EDITION 7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by.
The Brain. The Meninges (D.A.P.) Dura mater - outermost layer (tough mother) Arachnoid mater - no blood vessels, in between layer (resembles a spider.
Regions of the Brain Cerebral hemispheres Diencephalon Brain stem
Brain: Parts and Functions
The Brain and The Nervous System. Brain Facts The brain weighs 3 pounds. The brain consumes 20-30% of the body’s energy. There are about 100 billion neurons.
The Nervous System. Organization of the Nervous System Structural Classification Structural Classification Functional classification Functional classification.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings.
 WOlA&feature=player_detailpage WOlA&feature=player_detailpage 
Functions of Major Brain Regions
Essentials of Human Anatomy Nervous System II
Chapter 7 The Nervous System
12.1 – Structure of the Nervous System
The Nervous System DR JAMILA EL MEDANY.
THE BRAIN and Spinal Cord
The Brain.
Central Nervous System
The Brain.
CNS General Structure Composed of brain and spinal cord
Chapter 7 The Brain.
The Brain.
Essentials of Human Anatomy Nervous System II
The Central Nervous System
Chapter 7 The Nervous System
The Nervous System.
Spinal Cord ASCENDING - impulses travel to the brain (sensory)
Nervous System Anatomy
Nervous System Use your gray matter!.
Chapter 7 The Nervous System
The Reflex Arc Reflex – rapid, predictable, and involuntary responses to stimuli Reflex arc – direct route from a sensory neuron, to an interneuron, to.
Nervous System Use your gray matter!.
NERVOUS SYSTEM Aids in remembering, thinking, moving, being aware, and coordinating all other body functions to maintain homeostasis. Chapter 9.
Nervous System.
Your Brain Pawson, PVMHS 2014.
Chapter 7 The Nervous System
The Nervous System.
Central Nervous System
Central Nervous System
Chapter 7 The Nervous System
The Nervous System.
Chapter 49 Nervous Systems.
Introduction and Basic Structural Organization of the Nervous System
Nervous System By Dr. Maher T. AL-Hadidi And Dr. Amjad Al- Shatart
Nervous System By Dr. Maher T. AL-Hadidi And Dr. Amjad Al- Shatart
The Central Nervous System (CNS)
The Nervous System.
The Brain.
Central Nervous System Communication and coordination
HUMAN BRAIN BY, BINCY CHERIAN ASST. PROF COLLEGE OF NURSING KISHTWAR.
Essentials of Human Anatomy Nervous System II
8 The Nervous System.
Central Nervous System
Presentation transcript:

CENTRAL & PERIPHERAL NERVOUS SYSTEMS

Structural Divisions of Nervous System Central Nervous System (CNS) Brain, Spinal Cord Peripheral Nervous System (PNS) Cranial Nerves Spinal Nerves

CNS – Brain Four Major Brain Regions: Cerebrum Diencephalon Brainstem Cerebellum

CNS – Cerebrum Cerebrum Largest, Superior Two Hemispheres Separated By Longitudinal Fissure Connected by Corpus Callosum (myelinated axons) Two Layers: Outer Cortex (gray matter) & Inner White matter

Cerebrum continued Cerebral Cortex Neuron Cell Bodies & Unmyelinated processes Gyri (ridges) & Sulci (grooves) White Matter (Myelinated axons) Nuclei (gray matter imbedded in white) Neurons in CNS are MULTIPOLAR; each has tens of thousands of dendrites. Each Neuron makes anywhere from 1,000 to 10,000 synapses with other neurons. A sand grain sized piece of gray matter contains 100,000 neurons & 1 billion synapses! Spontaneous smiles produced by basal nuclei. Forced smiles are produced by (motor) cortex which controls voluntary, skilled movements. Smiling requires very complex sequence of movements & involuntary control by basal ganglia results in better smile. The cerebral cortex is 6 layers of cells thick.

Basal Nuclei – 4 masses of gray matter with complex functions (in movement).

Lobes of Cerebrum Each Cerebral Hemisphere has 5 Lobes: Frontal – Personality, concentration, problem solving, voluntary control of skeletal muscle Parietal – Skin sensation, speech & language, expression of thought Temporal – Hearing, smell Occipital – Vision Insula – Bodily self-awareness; sense of disgust to smells, contamination, mutilation Insula: not well understood; some language function (rhyme recognition, sound sequences), upset stomach, full bladder, behavioral influences on cardiovascular (heart briefly stops when startled)

CNS - Diencephalon Diencephalon Enclosed by Cerebrum Between Cerebrum & Brainstem Epithalamus Thalamus Hypothalamus

Diencephalon: Epithalamus Superior to Thalamus & Third Ventricle Contains the Pineal Gland, Produces Hormones Habenular nuclei located here involved in emotional responses to odors

Diencephalon: Thalamus “Relay station” for all sensory impulses to cerebral cortex Consists of 2 lobes (may be joined by “Intermediate Mass” (a bridge of gray matter) Third ventricle is superior & medial to thalamus Thalamus sensory information passes to sensory cortex; only a small portion allowed to pass on. Intermediate mass contains no fibers; is a projection of gray matter. In 30% of people, the 2 intermediate masses do not join. Mammillary bodies process sensory info including olfactory sensations. Also nuclei involved in eating, chewing, licking, swallowing.

Basal Nuclei – 4 masses of gray matter with complex functions (in movement).

Diencephalon: Hypothalamus Below thalamus Controls pituitary function Controls regulatory functions Helps regulate body temperature Feeding/Thirst Body temp is regulated by adjusting blood flow & sweat gland activity

CNS - Brain Stem Between Diencephalon & Spinal Cord Three parts: Midbrain Colliculi – visual & auditory nuclei Pons – Below midbrain; joins cerebellum to brainstem Medulla Oblongata – Below Pons, Regulates heartbeat & breathing; has role in consciousness; joins brain & spinal cord Midbrain directs reflexive responses to visual & auditory stimuli (coordinates head, eyes, & trunk movements). Also helps maintain consciousness. Pons – tracts & relay centers joining cerebellum to brainstem. Also nuclei involved in somatic & visceral motor control. Medulla – relays sensory info to thalamus & other parts of brainstem. Also contains major centers that regulate autonomic function (i.e. Heart rate, BP & digestion), and reflexes (vomiting, swallowing, sneezing, coughing, hiccupping).

CNS - Cerebellum Inferior to Cerebrum, Posterior to Brain Stem Joined to brainstem by Pons Two hemispheres with convoluted surfaces Outer Gray Matter Arbor Vitae (Inner, Branching White Matter) Provides involuntary coordination of body movements Automatic processing center. 2 primary functions: adjusts postural muscles of the body & programs & fine-tunes movements controlled at conscious & subconscious levels (compares motor commands with your sense of body position and makes any adjustments necessary to make movements smooth).

We really don’t know how the brain translates patterns of nerve activity into conscious experience (e.g. pain, pleasure or color)

Protection of the CNS CNS Protected by: Bone Skull (Brain) Vertebrae (Spinal Cord) Meninges (C.T. membranes) Cerebrospinal Fluid (CSF) Blood-Brain barrier (harmful substances in blood)

CNS – Meninges Meninges - CT Membranes between Bone & CNS Dura Mater Outer, Tough, Fibrous, Double Extends down vertebral cavity, beyond end spinal cord Dural Sinuses – Veins between layers Dural Folds – Innermost layer extents into fissures Epidural Space – Between walls of vertebral cavity & Dura of spinal cord

CNS – Meninges Arachnoid Mater Thin, Spidery, Middle Extends past spinal cord Subdural Space – Between Dura & Arachnoid Subarachnoid Space – Between Arachnoid & Pia; Contains CSF Pia Mater Innermost, Delicate Attached to Surface of Brain & Spinal Cord Highly Vascular

CNS - Brain Ventricles Ventricles Cavities within Brain, Filled with CSF Continuous with Subarachnoid Space & Central Canal of Spinal Cord Lateral – Largest Two, within Cerebral Hemispheres Third – Narrow, Midline, Diencephalon Fourth – Brain Stem, Continuous with Central Canal of Spinal Cord

Fig. 8.36

CNS - Cerebrospinal Fluid (CSF) Secreted by Choroid Plexuses (capillaries & ependymal cells in ventricles) Clear, Similar to Blood Plasma Most CSF produced by Lateral Ventricles Circulates through Ventricles, Subarachnoid Space, Central Canal Supports, Absorbs Shocks, Provides Nutrients Sample via Spinal Tap (Subarachnoid Space, L-4) CSF produced at a rate of about 500ml/day.

Spinal Tap

CNS – Spinal Cord Protected by Bone, Meninges, CSF Vertebral Cavity Extends from Medulla Oblongata (Through Foramen Magnum) to L2 16-18 inches Two Enlargements (Limb Control): Cervical (Shoulder & Arms) Lumbar (Pelvis & Legs) The lumbar enlargement is also called the lumbosacral enlargement.

CNS – Spinal Cord continued Outer White Matter – Bundles of Myelinated Axons Ascending Tracts or Pathways Sensory Descending Tracts or Pathways Motor

CNS – Spinal Cord continued Inner Gray Matter Neuron Cell Bodies (somas) & unmyelinated processes Dorsal Gray Horn – Interneuron Somas Ventral Gray Horn – Somas of Motor Neurons Central Canal in Gray Commissure Lateral gray horns contain cell bodies of motor neurons of the ANS

Peripheral Nervous System - PNS Consists of: Peripheral Nerves: Cranial Nerves Spinal Nerves & Nerve Plexuses Ganglia Sensory Receptors Carries Sensory Information & Motor Commands

PNS – Nerves Bundles of Axons Sensory, Motor or Mixed CT Reinforced Endoneurium – Surrounds each axon Perineurium – Around each fascicle (group of axons) Epineurium – Tough, Fibrous C.T. around Nerve Entire nerves are either sensory, motor, or mixed in function; the individual neurons within the nerve determine the overall function of the nerve. Each neuron can transmit in only one direction (i.e afferently or efferently).

PNS – Cranial Nerves Twelve Pairs Function: Sensory Motor Mixed

PNS – Spinal Nerves 31 Pairs: 8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal All are Mixed; both Sensory (Afferent) & Motor (Efferent) Attach to Spinal Cord by Ventral & Dorsal Root

Fig. 8.21

Reflex Arcs Simple Pathway May not involve brain Results in Reflex Fast, Predictable Automatic motor response Five Components: Receptor End of dendrite of sensory neuron (or more complex) Responds to specific stimuli Sensory Neuron (Receptor to CNS)

Reflex Arcs continued Interneuron CNS Gray Matter Usually one but may be 0 or >1 Transmits, Inhibits, or Reroutes to Motor Neuron Motor Neuron (CNS to Effector) Effector Muscle or Gland; responds to motor impulse Response is Reflex (e.g. knee jerk, secretion of digestive juices, pain withdrawl)

Types of Reflexes Somatic reflexes: Involuntary (Autonomic) reflexes: Skeletal muscle Involuntary (Autonomic) reflexes: Smooth muscle Heart and blood pressure Glandular secretion Digestive system regulation