Nervous System Organization Flashcards
(28 cards)
Nervous system
Nervous system: General Functions
General Functions
Sensory Funcgtions
* Receives incoming information (stimuli) from sensory Receptors
Integrative Function
* Interprets and processes information to determine appropriate response
Effector Function
* Produces outgoing signal to initiate a response in muscles (Skeletal, Smooth, Cardiac) or glands
The Nervous system
The nervous system
Major Organs:
* Brain
* Spinal Cord
* Peripheral Nerves
* Sense Organs
Functions:
* Direct immediate response to stimuli
* Coordinates or moderates activities of other organ systems
* Provides and interprets sensory information about external conditions
Orginization of the Nervous system
Orginization of the Nervous system
Two Primary Subdivision
CNS (Central Nervous system)
* Brain and spinal cord
PNS (peripheral Nervous System)
* Neural tissue outisde CNS
CNS
CNS
CNS (Central Nervous System)
* Brain and spinal cord
* Contained within skull and vertebral column
Integrative in function
* Simple reflexes
* Complex Reflexes
* Higher order functions (memory, learning, intelligence)
PNS
PNS
PNS (Peripheral Nervous System)
* Neural tissue outside CNS
Mostly outside of skull and vertebral column
Peripheral Nerves
* Cranial nerves and spinal nerves
Peripheral Ganglia
* Sensory ganglia
* Autonomic Nervous system ganglia (sympathetic, Parasympathetic)
Sensory organs of vision, hearing, etc…
peripheral Nerves
peripheral Nerves
peripheral Nerves
Afferent
* Afferent divison brings sensory information from receptors
Efferent
* Efferent division carries motor commands to effectors
- Somatic nervous system to skeletal muscles
- Autonomic nervous sstem to cardiac muscle, smooth muscle, and glands (parasympathetic, and Sympathetic)
Cells of the Nervous System
Cells of the Nervous System
Nerve cells (neurons)
* Electrically active cells that process and conduct information in the form of electrical signals - action potentials
Neuroglia (glial cells) - support cells
* PNS: Satelite cells (chemical regulator), and schwan cells (mylein sheath producer)
* CNS: Oligodendrocytes (mylein sheath producer), astrocytes (Chem reg), Microglia, and ependymal cells
Functional orginization of the Nervous System
Functional orginization of the Nervous System
Collection of nerve cell processes (fibers) for transmission of information
* PNS - Nerve
* CNS - white matter, fiber tract, column
Collection of nerve cells bodies for processing of information
* PNS - ganglia
* CNS - Grey mater, nucleus, cortec
Neuroglial cells surround and support both nerve cell bodies and processes
Grey Matter of Spinal Cord
Grey Matter of Spinal Cord - Processing and Integration
- Posterior (dorsal) gray horns cpntains somatic and visceral sensory nuclei
- Anterior (ventral) gray horns deal with somatic motor control
-
Lateral gray horns contain visceral (ANS) motor neurons
Size of grey matter (# of nerve cells) related to size of the body aera intervated - Cervical and lumbar enlargemnts
White matter of spinal cord
White matter of spinal cord - transmission of information
Divided into six columns (funiculi) containing tracts
* Posterior, Anterior, Lateral columns
Ascending tracts relay information from the spinal cord to the brain
Descending tracts carry information from the brain to the spinal cord
Adult Spinal cord
Adult Spinal Cord
- A slingle continous structure
- 31 spinal cord segments: defined by spinal nerves (8C, 12T, 5L, 5S, 1Co)
- Dorsal (posterior) root of spinal nerve is senesory (afferent)
- Ventral (anterior) root of the spinal nerve is motor (efferent)
- Spinal nerves are a mixture of sensory and motor fibers
- Each spinal nerve receives sensory input from one dermatome - region of the body
Adult Brain and Brainstem
Adult Brain and Brainstem
- Telencephalon - cerebrum or cerebral hemispheres
- Diencephalon - thalamus and hypothalamus
- Mesencephalon - Midbrain
- Metenchephalon - Pons and cerebellum
- Myelencephalon - Medulla oblongata
Grey Matter of Brainstem and Brain
Grey Matter of Brainstem and Brain - Processing and integration
Cortex or cerebral hemispheres
* Highest level of processing
Basal nuclei of cerebral hemispheres
* Motor Control
Thalamus
* Processing sensory information
Hypothalamus
* ANS and Endocrine controll
Cortex or cerebellum
* Motor Controll
Various brainstem nuclei
White Matter of Brainstem and Brain
White Matter of Brainstem and Brain - Transmitting Information
- Projection Fibers - ascending and descending tracts of the spinal cord, brain stem, and brain
- Ascending Fibers - connect between aeras on the same side of the CNS
- Commissural Fibers - connect between aeras on opposite sides of the CNS
Embryology of the Brain
Embryology of the Brain
Brain and spinal cord Tissue
* Neurons and glial cells
* Develop from the cells in the walls of the developing hollow neural tubes
Ventricles of the brain and spinal canal of spinal cord
* Develop from hollow ceneter of developing neural tubes
Protection and Support of the CNS
Protection and Support of the CNS
Multiple support and protective systems
* Skull, Vertebrae, Ligaments, Muscles
* Meninges
* Cerebral Spinal Fluid (CSF)
* Blood-Brain barrier
Meninges
Meninges
Specialized connective tissue layers
* Dura Mater
* Arachnoid
* Pia Mater
Provide physical stability and shock absorption
Support blood vessels entering and exeting CNS tissue
Meninges
Meninges
Specialized connective tissue layers
* Dura Mater
* Arachnoid
* Pia Mater
Provide physical stability and shock absorption
Support blood vessels entering and exeting CNS tissue
Spinal Meninges
Spinal Meninges
Anchor Spinal Cord
* BAse - to coccyx via filum terminale and coccygeal ligament
* Top - to periostem of foramen magnum
* Laterally - denticulate ligaments
Provide Cushioning
* Epidural space with epidural fat separates dura mater from walls of vertebral canal
* Subarachnoid space is filled with CNS
Cranial Meninges
Cranial Meninges
Continuous with the three layers of the spinal cord
* Two layers of dura mater
Folds of dura mater help stabilize the position of the brain
* Falx cerebri, Tentorium Cerebelli, Falx Cerebelli
* Contains sinuses that serve as veins
Subarachnoid space filled with CSF
Cerebrospinal Fluid (CSF)
Cerebrospinal Fluid (CSF)
Produced in the ventricles
* Fluid diffuses out of capillaries of the choroid plexus into ventricles
* Exits ventricles into subarachnoid space through apertures of 4th ventricles
* Circulates through subarachnoid space of spinal and cranial meninges
* Exits across the arachnoid granulations into the superior sagital sinus (vein)
cerebrospinal Fluid (CSF)
cerebrospinal Fluid (CSF)
- Comes from blood, returns to blood
- Transports nutrients, chemical messengers, and wate products
- Provides cushioning and boyancy
- Blockage of CSF circulation causes pressure in ventricles
- Enlarging ventricles damage neural tissue
- Hydrocephalus - Water on the brain
Neuron Clasification
Neuron Clasification
- Motor (Efferent)
- Sensory (Afferent)
- Interneurons (association Neurons)
- Located mostly within the CNS
- Interconnect among nerve cells
- Function in processing
Cells of the Nervous System
Cells of the Nervous System
Nerve cells (neurons)
* Electrically active cells that process and conduct information in the form of eletrical signals
Neuroglia (glial Cells)
* Several kinds of support cells
* PNS: Satelitle cells, schwan cells
* CNS: oligodendrocytes, astrocytes, microglia, epyndymal cells
