What is the NERVOUS SYSTEM responsible for?
Communication and control within the body
What are the 2 main structural divisions?
Central Nervous System (CNS) and Peripheral Nervous System
Central Nervous System
Brain and Spinal cord
Peripheral Nervous System
Lies outside the Central Nervous System
What are the 2 main divisions of the PERIPHERAL NERVOUS SYSTEM?
Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System
Sends messages from the CNS to the skeletal muscles
Autonomic Nervous System
Transmits messages from the CNS to the smooth muscles, cardiac muscles, and certain glands
What is the AUTONOMIC SYSTEM sometimes called?
Involuntary Nervous System
Neurons
Transmitter cells that carries messages to and from the brain and spinal cord
Neuroglial or Glial Cells
Supports cells to the neurons; Supports and protects the neurons while producing cerebrospinal fluid (CSF)
What are the 3 main structures of a NEURON?
The cell body, axon, and dendrites
Cell Body
Contains a nucleus surrounded by cytoplasm
Axon
Cylindric extension of a nerve cell that conducts impulses away from the neuron cell body
Dendrites
Branching structures that extend from a cell body and receive impulses
Synapse
Gap (space) in between each neuron
Neuromuscular Junction
Area between the ends of a large myelinated nerve fiber and a fiber of a skeletal muscle
Why is the area of NEUROMUSCLUAR JUNCTION necessary?
In order for the body to function
What are the best known NEUROTRANSMITTERS?
Acetylcholine, Norepinephrine, Dopamine, and Serotonin
Acetocholine
Spills into the synapse area and speeds the transmission of the impulse
Norepinephrine
Effect on maintaining arousal (awakening from a deep sleep), dreaming, and regulation of mood
Dopamine
Primarily affects motor function and has a role in emotional responses
Serotonin
Induces sleep, affects sensory perception, controls temperature, and has a role in control of mood
Myelin
White, waxy, fatty material covering many axons and dendrites
What does MYELIN do?
Increases the rate of impulse transmission and protects and insulates nerve fibers
Nodes of Ranvier
Further increases the rate of transmission because the impulse can jump from node to node
In the peripheral nervous system what is the MYELIN produced by?
Shwann cells
Neurilemma
Helps regenerate injured axons
Where does the regeneration of nerve cells only occur?
The peripheral nervous system
Brain
One of the largest organs; Weighing approx 3 pounds
What is the 4 principal parts of the BRAIN?
The cerebrum, the diencephalon, the cerebellum, and the brainstem
What is the largest part of the BRAIN?
The cerebrum
Cerebral Cortex
The outer portion of the cerebrum composed of gray matter
Gyri
Convolutions; Arranged in folds
Sulci
Grooves or fissures
Corpus Callosum
Connecting structure or bridge
What are the 4 lobes of the CEREBRUM?
Frontal, Parietal, Temporal, and Occipital
Functions of the FRONTAL LOBE
Written speech, motor speech, motor ability, intellect, and judgement information
Functions of the TEMPORAL LOBE
Memory storage, integration of auditory stimuli
Functions of the OCCIPITAL LOBE
Interpretation of visual impulses from the retina and understanding the written word
Functions of the PARIETAL LOBE
Recognition of body parts, determination of left from right, and determination of shapes, sizes, and distances
Expressive Aphasia
Not be able to speak
Receptive Aphasia
Hears sounds but has no meaning
Diencephalon
Lies beneath the cerebrum and contains the thalamus and the hypothalamus
What is DIENCEPHALON often called as?
Interbrain
Thalamus
Acts as a relay station for some sensory impulses and interprets messages such as pain, light touch, and pressure
Hypothalamus
Plays a vital role in the control of body temperature, fluid balance, appetite, sleep, and certain emotions
What does the DIENCEPHALON control?
The sympathetic and parasympathetic division of the autonomic system are under the control of the hypothalamus as is the pituitary gland
What is the 2nd largest portion of the BRAIN?
The cerebellum
What is the CEREBELLUM responsible for?
Coordination of voluntary movement and maintenance
Where is the BRAINSTEM located?
On the base of the brain
What does the BRAINSTEM contain?
The midbrain, the pons, and the medulla oblongata
Midbrain
Responsible for motor movement and the relay of impulses; And responsible for auditory and visual reflexes
What CRANIAL NERVES is the MIDBRAIN?
Cranial Nerves III and IV
Pons
Connects the Midbrain and Medulla Oblongata; Responsible for sending impulses to structures inferior and superior to it
What CRANIAL NERVES is the PONS?
Cranial Nerves V through VIII
Medulla Oblongata
Controls heartbeat, rhythm of breathing, swallowing, coughing, sneezing, vomiting, and hiccups
What CRANIAL NERVES is the MEDULLA OBLONGATA?
Cranial Nerves IX and XII
How long is the SPINAL CORD?
17 to 18 inches
The SPINAL CORD extends from where?
The brainstem to the second lumbar vertebra
What are the 2 main functions of the SPINAL CORD?
Conducting impulses to and from the brain and serving as a center for reflex actions
Meninges
The brain and spinal cord are surrounded by 3 protective covering
What are the 3 protective coverings?
The dura mater, the arachnoid membrane, and the pia mater
Dura Mater
The outermost layer
Arachnoid Membrane
The second layer
Pia Mater
The innermost layer
What does the PIA MATER provide?
Oxygen and nourishment to the nervous system
How many pairs of spinal nerves does the PERIPHERAL NERVOUS SYSTEM contain?
31
What is the PERIPHERAL NERVOUS SYSTEM composed of?
31 pairs of spinal nerves, 12 pairs of cranial nerves, and the autonomic nervous system
Spinal Nerves
Transmit sensory information to the spinal cord through afferent neurons and motor information from the CNS to the body through efferent nerves
Afferent
To the spinal cord
Efferent
Away from the spinal cord
Cranial Nerves
Conduct impulses between the head, neck and brain
Cranial Nerve I
Olfactory Nerve
Olfactory Nerve
Sense of smell
Cranial Nerve II
Optic Nerve
Optic Nerve
Vision; Controls impulses from the eye to the brain
Cranial Nerve III
Oculomotor Nerve
Oculomotor Nerve
Eye movement and pupilary control; Controls impulses from the brain to the eye muscles
Cranial Nerve IV
Trochlear Nerve
Trochlear Nerve
Controls eye movement; Controls impulses from the brain to the eye muscles
Cranial Nerve V
Trigeminal Nerve
Trigeminal Nerve
Sensations of face, scalp, and chewing muscle
Cranial Nerve VI
Abducens Nerve
Abducens Nerve
Allows eyes to turn outward; Impulses from the brain to external eye muscles
Cranial Nerve VII
Facial Nerve
Facial Nerve
Control sense of taste and contraction of muscle for facial expressions; Impulses from tastebuds
Cranial Nerve VIII
Vestibulocochlear Nerve
Vestibulocochear Nerve
Hearing and sense of balance; Impulses from the ear to the brain
Cranial Nerve IX
Glossopharyngeal Nerve
Glossopharyngeal Nerve
Sensation of the throat, swallowing movements, and secretions of saliva
Cranial Nerve X
Vagus Nerve
Vagus Nerve
Sensation of throat, larynx, and thoracic and abdominal organs
Cranial Nerve XI
Spinal Accessory Nerve
Spinal Accessory Nerve
Shoulder movements and turning movements of the head
Cranial Nerve XII
Hypoglossal Nerve
Hypoglossal Nerve
Controls tongue movements; Impulses from the brain to the tongue
What system is responsible for maintaining internal homeostasis?
Autonomic Nervous System