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Nervous System by Klaus Ramirez period 5 - Coggle Diagram
Nervous System by Klaus Ramirez period 5
Major functions of the nervous system
Sensory Function
; Provided by sensory receptors which allows info to travel from receptor to sensory neurons which transport info into the CNS.
Integrate Function
; Coordinates information into the CNS and processes this info for basis of decision making
Motor Function
; Nerve Impulses (CNS) are conducted along motor neurons.
Major Divisions and Subdivisions
Peripheral Nervous System (PNS)
; Consists of nerves that connect the CNS to body parts and consists of cranial nerves, arising from the brain and spinal nerves arising from the spinal cord.
*Autonomis nervous system
; Connects the CNS to viscera fn controls subconscious activities.
Somatic Nervous System
; Connects to the CNS to viscera and controls subconscious activities.
Central Nervous System (CNS)
Controls the brain and spinal cord
*Autonomic Nervous System (ANS)
; Controls visceral motor functions of smooth muscle, cardiac muscle and glands.
Sympathetic Division
: Active in conditions of stress or emergency (fight or flight response)
The axon then leaves the spinal nerves and proceeds into the
sympathetic (paravertebral) ganglia
, a chain of sympathetic ganglia close to the vertebral column on each side.
There they synpase with
postglanglionic neurons
, whose long axons return to the spinal nerves and then proceed to a visceral effector. Sometimes they synapse in
collateral ganglia
Short
preganglionic fibers
in this division arise from neurons in the gray matter in the thoracic and lumbar regions of the spinal cord.
Parasympathetic Division
: Active under normal, restful conditions (rest and digest)
Classifications of neurons
Structural Classification
Multi polar neurons
; cell bodies are multiple
Bipolar neurons
; 2 extending from cell body
Unipolar neurons
; Only one process extending
Functional Classification
Inter neurons (associations or inter crucial neurons)
; Multipolar neurons lying within the CNS, forms links between other neurons
Motor neurons
; Multipolar neurons that conduct import from the CNS to the peripheral effectors.
Sensory (afferent) neurons
: conduct impulses from peripheral receptors to the CNS (usually uni or bi)
Tissues
Connective tissue
; Supports soft parts and bind structures together
Muscle Tissue
; Produce Body movements
Epithelial tissue
; Form protective coverings and function in secretion and absorption
Nervous tissue
; Conduct impulses to control and coordinate body activities
Connective Tissue Coverings
Perimysium
extends inward from epimysium: it surrounds bundles of skeletal muscle fibers called
fascicles
within each muscle
Endomysium
; each muscle cell (fiber) is covered by a connective tissue layer called endomysium
Epimysium
; the layer tha connects tissue around each skeletal muscle
Major Parts and Functions of the brain
Lobes
Occipital Lobe
; association areas help analyze visual patterns and combination visual images with other sensory info
Frontal Lobe
; associations areas control a number of upper intellectual processes (problem solving
Temporal Lobe
Parietal Lobe
; association areas function in understanding speech and choosing the proper words.
External
Cerebrum
;coordinates muscular activity
Cerebellum
; largest portion, associated with higher mental functions and sensory and motor functions
Corpus callosum
; flat bundle of nerve fibers that connect the hemisphere
Brainstem
; coordinates and regulates visceral activities and connects different parts of the nervous system
Gyri
; Ridges
Sulci
; Grooves
Superior colliculus and inferior colliculus
; located just below the visual processing center. Receive auditory information
Medula
; found in base of brain, it's essential in passing messaged from spinal cord to brain
Pons
Optic Nerves
Internal
Hypothalamus
Thalamus
Corpus Callosum
Fourth Ventricle
Fornix
Mammillary Body
Major parts and functions of the spinal cord
;
Major Functions
Transmit impulses to and from the brain and to house spinal reflexes
Ascending tracts
carry sensory information to the brain
Descending tracts
carry motor information from the brain
Action Potential and the nerve impulse
Types of Impulses
Continuous conduction
; Occurs in unmyelinated axons, conduct impulses sequentially over the entire length of their membrane.
Saltatory conduction
; Occurs in myelinated axons. The myelin sheath insulates axons from ion movement across the cell membrane. Impulses "jump" from one
Node of Ranvier
to the next, since sodium and potassium channels occur only at the nodes.
Action Potential Steps
3.
Sodium channels in the trigger zone of the axon open
4.
Sodium ions diffuse inward, depolarizing the axon membrane
2.
Threshold stimulus is recieved
5.
Potassium channels in the axon membrane open.
1.
Neuron membrane maintains resting potential
6.
Potassium ions diffuse outward, repolarizing the axon membrane
7.
The resulting action potential causes a local electric current that stimulates the adjacent portions of the axon membrane
**8. A series of action potentials occur along the axon.
Cranial Nerves
V Trigeminal (Mixed)
Maxillary division
; Sensory fibers conduct impulses from the upper teeth, upper gum, upper lip, lining of the palate and skin of the face.
Mandibular division
; Sensory fibers conduct impulses of muscles of mastication and to muscles in the floor of the mouth
Opthalamic division
; Sensory fibers conduct impulses from the surface of the eyes, tear glands, scalp, forehead and upper eyelids
VI Abducens (Primarily)
Motor fibers conduct impulses to muscles that move the eyes. Some sensory fibers conduct impulses associated with the condition of muscles
IV Trochlear (Primarily motor)
; Motor fibers conduct impulses to muscles the move the eyes.
VII Facial (Mixed)
; Sensory fibers conduct impulses associated with taste receptors of the anterior tongue. Motor fibers conduct impulses to muscles of facial expression, tear glands and salivary glands.
III Oculomotor (Primarily motor)
Motor fibers conduct impulses to muscles that raise eyelids, move eyes, adjust the amount of light entering the eyes, and focus lenses.
VIII Vestibulocochlear (Sensory)
Cochlear branch
; Sensory fibers conduct impulses associated with the sense of hearing
Vestibular branch
; Sensory fibers conduct impulses associated with the sense of equilibrium
II Optic (Sensory)
; Sensory fibers conduct impulses associated with the sense of vision
IX Glossopharyrigeal (Mixed)
; Sensory fibers conduct impulses from the pharynx, tonsils, posterior tongue and carotid arteries.
I Olfactory (Sensory)
; Sensory fibers conduct impulses associated with the sense of smell
X Vagus (Mixed)
Somatic motor fibers conduct impulses to muscles associated with speech and swallowing; autonomic motor fibers conduct impulses to the heart, smooth muscle and glands in the thorax.
XI Accessory (Primarily motor)
Cranial Branch
; Motor fibers conduct impulses to muscles of the soft palate, pharynx and larynx
Spinal branch
; Motor fibers conduct impulses to muscles of the neck and back
XII Hypoglossal (Primarily motor)
Motor fibers conduct impulses to muscles that move the tongue
Spinal Nerves
Cervical plexus
(C1-C4); lie on either side of the neck; supply muscles and skin of the neck, include the phrenic nerves which control the diaphragm.
Intercostal nerves
(T1-T11): Anterio branches of the thoracic spinal nerves do not form plexuses but become the intercostal nerves
Brachial Plexus
(C5-T1); Arise from the lower cervical and upper thoracic nerves; supply muscles and skin of arms, forearms and hands; lead into the upper limbs; include the musculocutaneous, ulnar, median, radial and axillary nerves.
Lumbosacral plexus
(l1-S4); Arise from the lower spinal cord; supply muscles and skin of the lower abdomen, external genitalia, buttocks and legs; include the obturator, femoral and sciatic nerves.
Neurotransmitters
Monoamines
Dopamine
CNS
; Deficiency in some brain areas
PNS
; Limited actions in autonomic nervous system
Serotonin
; (CNS) Primarily inhibitory leads to sleeping
Norepinephrine
CNS
; Creates a good sense of feeling good
PNS
; may excite autonomic nervous system
Histamine
(CNS); Release in hypothalamus promoted aleter.
Acetylcholine
; located in CNS, controls the skeletal muscle actions
Compare and Contrast the autonomic nervous system
Divisions
Sympathetic Division
; Active in conditions of stress or emergency (fight or flight)
Parasympathetic Division
; Active under normal, restful conditions (rest and digest)
Neurons
Preganglionic Neurons
; that leaves the CNS and synapse with one or positive neurons, which have cell bodies in an
autonomic ganglion
in the PNS.
Postganglionic neurons
; who's fiber (axon) leaves an autonomic ganglion and innervates a visceral effector
Similarities Between the Divisions
Both divisions release
acetylcholines called cholinergic fibers
Most organs receive innervation from both divisions**
Both are connected or in some way related with the
spinal cord
Both are responsible of control centers in the
brain
and
spinal cord
Differences between the Divisions
The
Symp.
Division has
short preganglionic fibers
which arise from neurons in the gray matter in the thoracic and lumbar regions
The
Parasymp
Division has long
preganglionic fibers
which arise from the brainstem and sacral region
Reflex arc
; Automatic response to change
Steps
;
Sensory receptors send pain messages along sensory neurons to the spinal cord.
Send impulses to interneurons where info is coordinated
Inter. issue motor commands to motor nuerons.
Motor signals are sent to flexor muscle to contract