Anatomy And Physiology Of The Nervous System Flashcards
Afferent
Conducting towards the center
Efferent
Conducting away from the center
Synapse
The junction of a nerve cell with another nerve cell, sensory receptor cell, or effector cell
The Nervous System- General
The system that controls and coordinating the actions of the effective tissues
Reflexes: automatic unconscious response to an effective tissue due to stimulus
The Nervous System-Areas to be Covered
Animals mainly call on reflexes to respond to things the majority of the time
Primary job: protection
The Nervous System-Functions
Irritability: internal and eternal…anything that affects an animals homeostasis
Conductivity: the signal from one point to another
Control, Integrate, Coordinate
Anatomy of the Nervous System: Nerve Cell (neuron)
Basic unit of the nervous system
If body is dead, neuron is dead
No centrioles in nerve system
You can’t make new neurons
Anatomy Of The Nervous System: Basic Parts
Cyton (or soma): nerve cell body (NCB)
Axon: get info
Dendrites: get info
Anatomy of the Nervous System: Nerve Fiber Sheaths
Gaps between two neurons plus effector tissue synapse on the end of the muscle bundle…motor end plate
Transmits acetylcholine
Chemical transmission
Anatomy of the Nervous System: nomenclature
Nuclei: groups of NCB found in CNS
Tracts: groups of processes found in CNS
Ganglia: groups of NCB found in PNS
Nerves: groups of processes found in PNS
ALL SPINAL NERVES ARE MIXED NERVESPlexus
A network of interconnecting nerves or blood vessels
Reflux
An involuntary response of a part to a stimulus
Stimulus
Anything external or internal, chemical or physical that can cause a response to an organ, system, or organism
The Nervous System: Nomenclature of major Divisions
Central Nervous System (CNS):nuclei and tracts located in brain or spinal cord
Peripheral Nervous System (PNS):ganglia and nerves not in brain or spinal cord
Somatic Portion:ganglia and nerves associated with skeletal muscle
Autonomic Portion: ganglia and nerves associated with cardiac, smooth, and glands
Brain-Cerebral Cortex
Higher brain functions (learning, reasoning, deduction, emotion)
Brain-Cerebellum
Maintains posture and controls locomotion
Brain-Thalamus
Receives and filters all incoming signals (except auditory) before going to cerebral cortex
Brain-Hypothalamus
Primary center for emotion and comfort (body temp, eating, sleeping, hormone release, drinking, sex)
Brain-Pituitary Gland
Releases tropic substances that controls growth and affects actions of glands like the thyroid, adrenal, gonads
Brain-Midbrain
Serves as switching and relay center between forebrain and hindbrain
Brain-Corpus Callosum
Connects the two hemispheres of the cerebrum
Brain-Medulla
Center for vital reflexes (breathing, heart rate, swallowing)
Brain-Reticular Formation
Modifies outgoing signals for movement, posture, and muscle tone, and prioritizes incoming signals. Contains reflex areas for breathing, sneezing, coughing, and vomiting
Brain-Spinal Cord
Extension of CNS that routes tracts to and from brain and PNS
Spinal Cord
Militated: motor
Unmilitated: sensory
Peripheral Nervous System (PNS)- Cranial Nerves
12pairs
Ventral surface of brain
Most connections with head and neck
Some are motor, sensory, both
I Olfactory
Sensory
Smell
II Optic
Sensory
Vision
III Oculomoter
Motor
Eyelid and eyeball movement
IV TRochlear
Motor
Innervates superior oblique
Turns eye downward and laterally
V Trigeminal
Sensory and Motor
Chewing
Face and mouth touch and pain
VI Abducens
Motor
Turns eyes laterally
VII Facial
Sensory and Motor
Controls most facial expressions
Secretion of tears and saliva
Taste
VIII Vestibulocochlear
Sensory
Hearing
Equilibrium Sensation
IX Glossopharyngeal
Sensory and Motor
Taste
Sense carotid blood pressure
X Vagus
Sensory and Motor
Senses aortic blood pressure
Slows heart rate
Stimulates digestion organs
Taste
Longest cranium nerve
XI Spinal Accessory
Motor
Controls trapezius and sternocleidomastoid
Controls swallowing and movements
XII Hypoglossal
Motor
Controls tongue movements
Peripheral
Spinal and Caudal nerves
Peripheral Nervous System: spinal nerves
Extends off Spinal Cord
Emerges behind each corresponding vertebrae
Amount of vertebrae (thoracic, lumbar, sacral)..number of nerves
Cervical…one additional region…1st pair emerges in front of atlas…dog has 8pairs of cervical spinus nerves
Caudal…less amount of pairs compared to vertebrae
Spinal terminates after lumbar region and beginning sacral
Peripheral Nervous System-Autonomic Portion Of a The Peripheral Nervous System
Sympathetic System and Parasympathetic System work against each other
Balanced…homeostasis
Info emerges through cranial nerves 3.7.9.10
Assume all visceral portion are both sympathetic system and parasympathetic system
Sympathetic System
Active state
Thoracic and lumbar connection has a ganglianated trunk
Close to spinal cord…
Short Preganglia Fibers
Long Postgangkia Fibers
Parasympathetic System
Relaxed and Digestive state
Two connections..brain and sacral
Close to organ that relates…
Long Preganglia Fibers
Short Postgangkia Fibers
Principle Properties of Nerve Fibers
Gates regulate from dendrite to nerve cell to axon…sends waves along the fiber…moves sodium in and potassium out
Conductivity: electrical in nature
Chief function of Nerve Fiber: conducts impulses and responsive to environmental changes
Impulse:wave down nerve fiber
The Nervous System: Resting Potential
Higher concentration of anions outside of cell
Interstitial fluid: outside….bathes the cells
Axolemma: barrier between inside of cell and interstitial fluid
Having sodium outside and potassium inside creates depolarization….until this occurs means refractory period
The Nervous System: Stimulus Applied
Action potential…influx NA and outflux K
The Nervous System: Impulse
“All or non effect” ….goes whole distance
Active state requires energy
Outer covering is neurolemma
Myelinated fibers produce more impulses faster than non myelinated due to insulation
The Nervous System: Refractory Period
Can’t send another impulse until out of resting period
The Nervous System: Conduction Speed
Small diameters produce more impulses than large diameters because they are slower
The Nervous System: Synapse
Release of the Neurotransmitter
Neurotransmitters: Norepenepherine
Released at motor end plate for sympathetic
Adrenergic…o-methyl-transferase (breaks down)
Neurotransmitters: Acetylcholine
Cholinergic…acetylcholesterase
Most common neurotransmitter
All synapses of parasympathetic and somatic motor end plates
Neuroinhibittors
Motor end plate of the sympathetic portion of the autonomic acetylcholine neuroinhibitors prevent release of NT
Antagonists
Cause a blockage which prevents release
Anesthetic
A pharmacological agent that causes loss of sensation and consciousness
Analgesic
A substance that causes the loss of pain without the loss of consciousness
Hormone
A substance formed on an organ or a part of an organ that is carried by the blood to other parts of the body where it can effect changes in function or the structure of other parts
The Nervous System: Reflex Action
Definition: unconscious, automatic response of a effective tissue by a stimulus for protection
Reflex Centers
Medulla Oblongata: in brain stem..controls heart rate, respiratory rate, blood vessel diameter, vessels for relaxing, coughing, vomiting, sneezing
Cerebellum: controls local motion and balance …equilibrium
Hypothalamus: controls hormones and body temperature
Cerebrum:controls visceral and auditory functions…dilation of eyes, auditory, startled reflex…act of protection
Conditioned vs Unconditioned Reflexes
Conditioned: reflex you have learned
Unconditioned: born with…like sweating
Somatic vs Visceral Reflexes
Somatic is skeletal muscle
Visceral is smooth, cardiac, glands muscle
Anesthetics
Primary used to reduce the sensation of pain
Local: specific site-may or may not cause unconsciousness…PNS
Poem earl: everything- causes unconsciousness
General Pathology of the Nervous System- Injury to a Cell Body
Whole neuron isn’t functional
Virus wipes out cell body
Distemper: attacks nerve cell body
General Pathology of the Cell Body: Injury to the Cell Processes
Blocks motor neurons
