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what is the overall functions of the Nervous system?
- Is the master controling communicating system.
- Its signaling device with body cells is electrical impulses which are rapid and cause immediate repsonses
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Which system control rapid electrical nerve impules?
A. Endocrine system
B. Nervouse system
B. Nervouse system - you got it.
The endocrine system organs produce hormones that are released into the blood
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What are the 3 Functions of the Nervous System:
- 1. Sensory Input
- 2. Integration
- 3. Motor Output
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What does the Sensory Input function do?
- Monitors changes occuring both inside & outside the body.
- * These changes are called stimuli
- * The info gathered is called sensory input
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Integration function does?
- Processes and interprets the sensory input.
- then decides what should be done
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Motor output function is?
- the effect or causes actioned by the muscles is the motor output.
- (ie. foot pressing the break pedal when you see a red light.)
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What is the body parts of the central nervous system (CNS)
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What is the body of the Peripheral Nervous System?
- 1. Cranial
- 2. Spinal Nerves
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What is another name for Sensory division?
Afferent divison
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What does afferent mean?
To go towards
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Afferent (or sensory) divison:
consists of nerve that send impulses to the central nervous system from various parts of the body.
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What is somatic?
(Remeber soma = body)
Are sensory fibers delivering impluses from the skin, skeletal musles and joints.
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Efferent (motor) division does?
carries impulses FROM the CNS to the effector organs, muscles and glands.
(These muscles bring about a motor response)
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The Motor division has two subdivision called:
- 1. Somatic (body) Nervous system
- 2. Autonomic Nervous system
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What does the Somatic (body) Nervous system do?
allows us to consciously, or voluntarily control our skeletal muscles
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What does the autonomic nervous system do?
- Regulates events that are automatic or involuntary.
- (ie. smooth and cardiac muscles and glands)
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What is another name for Autonomic Nervous system?
Involuntary nervous system
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Which two subdivision fall under the Involuntary Nervous System (Autonomic Nervous system)
- 1. Sympathetic
- 2. Parasympathetic
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Sympathetic Nervous System does?
- Is part of the autonomic nervous system
- Speeding up the heartbeat and causes contraction of the blood vessels.
- Regulates the function of the sweat glands and stimulates the secretion of glucose in the liver.
- Sympathetic nervous system is activated especially under conditions of stress.
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what does the Parasympathetic Nervous System do?
Sometimes called the rest and digest system Parasympathetic system conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract.
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What are two classifications of cells located within the Nervous System
- 1. Supporting cells aka Neuroglia
- 2. Neurons
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What is Supporting cells aka Neuroglia?
- this the the nerve glue
- generally support, insulate and protect the delicate neurons
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What is the fuction of the astrocytes cells?
- they have swallen ends that cling to neurons, bracing them and anchoring them to their nutrient cappilary blood line
- they protect neurons from harmful substances
- help control the chemical environment in the brain by "mopping up" leaked potassium ions
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What is the function of Microglia cells?
- Phagocytes that monitor the health of neurons
- dispose of debris, dead brain cells and bacteria
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What is the function of Ependymal cells?
- 1. These cells line the central cavities of the brain and spinal cord
- 2. The beating of their cilia helps circulate cerebrospinal fluid
- 3. Forms protective cushion around CNS
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What is the function of Oligodendrocytes cells?
1. Wrap their flat extensions (proceses) around the nerve fibers, producing fatty insulating coverings called myelin shealths
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Schwann cells
Form the myelin sheaths around nerve fibers that are found in PNS
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What do Neurons do?
Are highly specialized cells that transmit messages from one part of the body to another
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cell body
is the centre of the neuron
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Picture of a motor neuron
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Dendrites
convey incoming messages toward the cell body are called dendrites
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axons
Conduct nerve impulese away from the cell body
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myelin does?
- Protects and inculates the fibers
- Increases transmission rate of nerve impulese
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myelin sheath
is a tight coil of wrapped membranes that encloses the axon.
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Neurilemma
Is the outter of the Schwan cells
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Nodes of Ranvier are
The gaps formed between myelin sheath cells along the axons.
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What is an interneuron?
Interneuron is a nerve cell that links motor and sensory neurons, and it transmits impulses between them.
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What is a nerve?
one or more bundles of fibers forming part of a system that conveys impulses of sensation, motion, etc., between the brain or spinal cord and other parts of the body.
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what is white matter?
consists of dense (thick) collections of myelinated fibers (tracts)
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What is gray matter?
contains mostly UNmyelinated fibers and cell bodies
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What is the tracts of the nerve?
bundle of nerve fibers running through the CNS
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What are fasicles of the nerve?
a cluster or bundle of nerve fibers
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what is the epineurium of the nerve?
the outer layer of the peripheral nerves contained in the human body.
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what is the perineurium of the nerves?
It is a protective layer of tissue located around the nerves and internal organs
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Picture of the Epineurium, Perineurium Endoneurium layers
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What is the endoneurium layer of the nerve?
innermost layer of the perineurium
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Define the term "reflex".
rapid, predictable, and involuntary responses to stimuli
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Reflex Arcs: sensory receptors
Reacts to stimuli
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REfelx Arcs: sensory neurons
to connect the sensory receptor and effector organ (the muscle or gland that has been stimulated)
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Dorsal root ganglion
- Is a nodule (knot) on a dorsal root that contains cell bodies of sensory neurons.
- Is found in the afferent spinal nerves.
- Has axon, which relays information into the CNS
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Spinal cord cross section picture
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synapse
Information from one neuron flows to another neuron across a synapse. The synapse contains a small gap separating neurons.
- The synapse consists of:
- 1. A Presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles
- 2. A postsynaptic ending that contains receptor sites for neurotransmitters.
- 3. A synaptic cleft or space between the presynaptic and postsynaptic endings.
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What is an interneuron?
A nerve cell that acts as a link between sensory neurons and motor neurons
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what is a motor neuron?
Is a cell that directly or indirectly controls the contraction or relaxation of muscles
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mono-synaptic
single synapse in the spinal cord that links the transfer of information from a sensory neuron to the proper motor neuron
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What is a three neuron arc?
- A three neuron reflex arc has to do with a crossed extensor reflex arc
- (IE. When you step on a nail, your other leg extends to support your weight when you lift your other leg up off the nail) and a three neuron arc also has to do with the reflex that lifted your leg that stepped on the nail.
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What are the four main regions of the brain?
(pg. 241)
- 1. Cerebral Hemisphere
- 2. Diencephalon
- 3. Cerebellum
- 4. Brain Stem
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cerebral hemispheres
The cerebral hemisphere is one half of the cerebrum, the part of the brain that controls muscle functions and also controls speech, thought, emotions, reading, writing, and learning.
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Corpus callosum
White matter, like the corpus callosum, allows different parts of the brain to communicate with each other.
The brain is divided into a right and left hemisphere, and the two halves are connected by the corpus callosum
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Picture of the Corpus callosum
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Four Lobes of the Brain
- 1. Frontal Lobe
- 2. Occipital lobe
- 3. Parietal Lobe
- 4. Temperal lobe
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FRONTAL LOBE
Concerned with reasoning, planning, parts of speech and movement (motor cortex), emotions, and problem-solving
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PARIETAL LOBE Located behind the central sulcus.
Concerned with perception of stimuli such as touch, pressure, temperature and pain.
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TEMPORAL LOBE (Located below the lateral fissure.)
Concerned with perception and recognition of auditory stimuli (hearing) and memory (hippocampus).
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OCCIPITAL LOBE
Deals with many aspects of vision.
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fissure
seperate large regions of the brain
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The cerebral hemisphere are seperated by single deep fissure called L______ F______?
Longitudinal fissures
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Gyri
Are elevated ridges of tissue on the cerebral hemisphere
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Sulci
are shallow groves on the cerebral hemisphere
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central sulcus
seperates the frontal lobe and from the parietal lobe
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occipito-parietal sulcus
separates the parietal lobes and the occipital lobes in both hemispheres
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lateral sulcus
Marks the separation of the temporal lobe from the frontal and parietal lobes
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cerebral cortex
Speech, memory, logical, emotional, interpretations of sensation and voluntary movement are all functions of the cerebral cortext
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which lobes of the brain are the locations of the sensory cortex
Parietal lobe
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Where is the motor cortex in the brain?
frontal lobe
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Where is vision located in the brain?
(Which lobe?)
Vision is located in the posterior (back part of brain) part of the occipital lobe
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Which lobe is speech located in?
Frontal Lobe (BROCA is located in this lobe as well)
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Where is skeletal mucsle movement located? (lobe wise)
Frontal lobe
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Which lobe is taste located in?
frontal lobe
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Which lobe is muscle coordination located in?
frontal lobe
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which lobe is conscious thought in?
Frontal lobe
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Basal nuclei
Location?
function?
Location - Buried deep within the white matter of the cerebral hemisphere
Function - Body movement and coordination
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thalamus
- Location - encloses the shallow third ventrical of the brain
- function - is a relay station for sensory implulses UPWARD to sensory cortex
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Hypothalamus
- Location: under the Thalamus
- Function: regulates body temperature, water balance and metabolism. alont with thirst, appetite sex, etc
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Pineal gland
Location
Function
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pineal gland
Location - behind the third cerebral ventricle in the midline of the brain.
- Functions:
- Secretion of the Hormone
- Conversion of Nervous System Signals to Endocrine Signals
- Causes Feeling of Sleepiness
- Influences Sexual Development
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Midbrain - small part of the brainstem
The midbrain controls visual and auditory systems as well as eye movement.
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Pons
Location: Round structure that protudes below the mid brain.
- Function: pons literally means bridge
- serves as a communications and coordination center between the two hemispheres of the brain.
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Medulla oblongata
- * Location: Most inferior (bottom) part of brain stem
- * Function: controls heart rate
- * Blood pressure
- * Breathing
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Cerebellum
Location: Under the occiptal lobe of the cerebrum
function: controls skeletal muscle activity and controls our balance and equilibrium
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cerebellum
When we drink alcohol our balance is effecte b/c it affects our cerebellum
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Spinal cord
- lengths: 17 inches long (42cm)
- where it starts: Foramen
- Where is ENDS: Just below the ribs
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Cauda equina is?
The collection of spinal nerves at the inferior end of the vertebral canal
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where is the Cauda equina located?
in the lumbar region of the spine
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What is the function of the spinal cord?
- *Provides a TWO-WAY conduction path to and from the brain
- * controls numerous reflexes
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LO. # 28 - Cross section of spinal cord PICTURE:
dorsal horn
ventral horn
lateral horn
central canal
anterior median fissure
posterior median sulcus
dorsal root ganglion
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Cranial nerve
- * Primarily sever head and neck
- * There are 12 pairs of nerves that can be seen on the ventral (bottom) surface of the brain
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Spinal Nerves
- There are 31 pairs of spinal nerves
- Formed by ventral and dorsal roots of the spinal cord
- Are located in/on the spine
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What are MENINGES?
It is 3 connective tissue membranse covering and protecting the CNS
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Dura mater
- Is the outter most layer (leathery)
- Tough layer
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subdural space
a fluid-filled space or potential space between the dura mater and the arachnoid
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arachnoid mater
- * middle meningeal layer
- * Weblike (looks like cobwebs)
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subarachnoid space
attached to the inner most membrane
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pia mater
- Delicate
- Clings to the surface of the brain & spinal cord
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Cerebrospinal fluid (CSF)
- Is a watert broth similar to the make up of blood plasma.
- The CSF is formed by blood
- CSF around the brain and spinal cord forms a watery cushion the protects the nervous system from blows and trauma
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dural sinuses
are venous channels which drain the blood from the brain
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choroids plexuses
are clusters of capillaries hanging from the roof in each of the brian ventricles
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arachnoid villi
Absorption of the CSF into the blood stream takes place in the superior sagittal sinus through structures called arachnoid villi
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Blood- brain barrier
- *Are composed of the least permeable capillaries in the body.
- * Meaning very little passes through the blood brain barrier
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what does permeable mean
allowing liquids or gas to pass through it
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what does Blood- brain barrier let pass through?
water and essential amino acids pass through these barriers
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Blood- brain barrier block things like:
* urea, toxins, proteins, and most drugs
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Blood- brain barrier is useless?
against fats, respiratory gases and fat soluable molecules.
This is why blood borne alcohol, nicotine, and anesthetics can affect the brain
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