A&P Lec Test 2 Nervous System
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Together the endocrine and nervous system maintain ____
Name the 3 basic functions of the nervous system.
- 1. Sensory functions (externally)
- 2. integrating functions (within the spinal cord)
- 3. Motor functions (externally)
What are the 2 parts of the nervous system?
- 1. Central Nervous System
- 2. Peripheral Nervous System
What are the 2 parts of the Central Nervous System?
What are the 3 parts of the Peripheral Nervous System?
- 1. Cranial Nerves
- 2. Spinal Nerves
- 3. Autonomic Nerves
- -Sympathetic Division
- -Parasympathetic Division
Nueron's shape is adapted for their ___.
are involved in the transmission of impulses over long distances they are long, thin cells with branching processes at the ends, where they "connect" with other neurons.
What are the 3 sections of a Neuron?
- 1. Cell Body
- 2. Dendrites
- 3. Axons
the cell body of a neuron is aka ___.
soma or perikaryon
___is large and contains the nucleus of the cell. It also contains the majority of the cell organelles that synthesize the materials needed by the neuron, particularly energy (mitochondria) and neurotransmitters (synthesized by the ribosomes and rough endoplasmic reticulum).
The Cell body or Soma or Perikaryon
the areas containing large amounts of Rough Endoplasmic reticulum and ribosomes stain darkly and these areas are referred to as ____
_____ give the grey coloration to the areas of the spinal cord that contain the cell bodies of the neurons, the so called ______
The Nissl bodies, grey matter
____ are extensions from the soma that receive stimuli, or impulses from other neurons and convey this stimulation to the cell body.
____ may be modified into sensory receptors that receive or "sense" stimuli such as heat, cold, touch, pressure, stretch, or other physical changes from inside or outside of the body.
____ the other type of extension from the soma and conducts the nervous impulse away from the perikaryon toward another neuron or other type of cell.
____ is a single process, in contrast to the dendrite, which is very long.
Axons, unlike dendrites, are often covered in a fatty substance called ____
Myelin under the microscope appears ____.
Nervous tissue containing many myelinated axons is often referred to as _____.
Nervous tissue without myelin = ____
In some cases the axon may branch along its length producing _____ that allow the nervous impulse to be transmitted to more than one other cell.
Some axons have closely associated _____ for support, structure, and nutrition.
Name the 4 cells in the CNS.
- 1. Astrocytes
- 2. Oligodendrocytes
- 3. Microglia cells
- 4. ependymal cells
Name the 2 types of cells in the PNS
- 1. Satellite cells
- 2. Schwann cells
3 functions of Astrocytes
- 1.Responsible for the blood-brain barrier. The astrocytes secrete a substance that maintains the selective permeability of the endothelial cells lining the CNS
- 2. Structurally they support the neurons in the CNS by stabilizing the neurons from excessive movement and preventing damage to tissue.
- 3. Can change the composition of the interstitial fluid bathing the neurons
Function of the Oligodendrocytes
Like the Schwann cell of the PNS, they line the axolemma (neurolemma on the axon) with a sheath around every axon of the CNS.
What 2 things compose the Oligodendrocytes?
Protein and phospholipids
Those neuron with myelin sheath are said to be ____ and those without, _____
If a nerve has no myelin, the lining of the nerve is termed the _____
Neuro or Neurilemma
If the Nerve has myelin in the form of oligodendrocyte cell of the CNS or Schwann cells of the PNS, the outer lining of the myelin is then termed the ____ while the nerve lining is the _____.
Function to wander through the CNS and with their phagocytic activity, engulf and destroy cellular waste products, debris and pathogens
line the ventricles of the brain and spinal canal. They are responsible for the circulation of cerebrospinal fluid that surrounds and protects the brain and spinal cord. They may also aid in its production and the monitoring of its composition.
are located in the PNS. These surround the clusters of cell bodies known as ganglia, insulating therm from their surroundings.
the cell membrane of specialized glial cells called oligodendrocytes in the brain and spinal cord and Schwann cells in the nerves outside the brain and spinal cord.
the myelin sheath
Between adjacent ____ are small gaps in the myelin sheath called _____.
glial cells, Nodes of Ranvier
The myelin sheath and node of ranvier work together to enhance the _____ of _____ of the nervous impulses along the axon.
speed of conduction
What are the 4 classifications of Neurons?
- 1. Anaxonic neurons
- 2. Bipolar
- 3. Unipolar
- 4. Multipolar
there is no anatomical method differentiating between axons and dendrites. All cell processes appear similar. Name the Neuron classification.
have two processes arising from the cell body in the middle. Ear, eye, and nose. Name the Neuron classification.
have a continuous dendritic and axonal process with the cell body lying of to one side. Generally have a long axon and in PNS. Name the Neuron classification.
Have one axon from cell body with several dendrites coming in most common CNS. Name the Neuron classification.
Name the 5 types of Neuron classification based on function.
- 1. Sensory
- 2. Motor
- 3. Interneurons
- 4. Somatic sensory
- 5. Visceral sensory
of the PNS are afferent- they carry impulses from the sensory receptors toward or into the CNS. Name the Neuron Function Classification.
of the PNS are efferent- they carry impulses from the CNS to peripheral tissues, organs or organ. Name the Neuron Function Classification.
are those situated between sensory and motor neurons and are found only in the CNS. Name the Neuron Function Classification.
Neurons carry information from the external environment to the CNS. Name the Neuron Function Classification
Neurons carry information from within the animal (its organs and other systems). Name the Neuron Function Classification
A ___ nerve contains both afferent and efferent fibers and may innervate several different organs, muscles or glands.
Anatomically each axon is surrounded by a fibrous connective tissue called the _____ and that groups of these axons are held in bundles by connective tissue known as the _____. These are further held together by an outer fibrous sheath called the ____ which also encloses a blood supply and fat deposits.
endoneurium, perineurium, epineurium
is the study of the functioning of nervous tissue, I.e. how the neurons and glial cells transmit and process information.
We have already mentioned that neurons can transmit nervous impulses along their length. This impulse is in the form of an electrical stimulus caused by ______ of certain ion (Na+ and K+) on the inside and outside of the membrane of the neuron.
changing the concentration
_______ has a high concentration of sodium ions (Na+) and chloride ions (Cl-) whereas _____ has a high concentration of potassium ions (k+) and ______.
- The Extracellular Fluid (ECF),
- Intracellular Fluid,
- Negatively charged proteins
This difference in ionic concentration exists due to the ____ of the cell membrane that will not allow the ions to move across to equalize their distribution.
There is an overall excess of negative charge on the inner surface of the membrane when compared to the outer surface. This difference in electrical charge is called the _______ or _____ of the cell membrane.
transmembrane potential or resting potential
______ also exist across the cell membrane. K+ can move more easily out of the cell and Na+ can enter. Consequently, there is a loss of positive charge from the inside fo the cell, leaving the inside of the cell with a negative charge relative to the outside.
The difference in electrical charge is measured in ____.
For a resting neuron, the transmembrane potential is _____
0.07 V or -70mV
the channels will only allow K+ through (voltage-gated potassium channels), Na+ through (voltage-gated sodium channels), and the movement is with chemical gradient, I,e. from high to low concentration. The transport of K+ or Na+ therefore does not require any input of energy and can be described as ____.
For every 2 __ ions to the outside of the nerve, there are 3 __ ions to the inside during the ____ process.
2 K+, 3 Na+, Depolarization process
When both the chemical and electrical gradients are considered together, we call this the _____.
In neurons, what are the 2 major ions that play a role in transmission of the nervous impulse?
K+ and Na+
If the cell is to maintain ____ then it must be able to retrieve some of the lost K+ from ____ the cell and rid of excess Na+ from the ___ of the cell.
homeostasis, outside, inside
Energy is used to activate a mechanism known as ___.
This pump permits the exchange of intracellular Na+ for extracellular K+, using a carrier protein molecule located in the cell membrane, called _____.
The sodium/potassium ATPase pump
This mechanism uses energy derived from the conversion of adenosine triphosphate to adenosine diphosphate to move the ions against their electrochemical gradients, a process known as ____
K+ moves out of the neuron and the Na+ moves into the neuron normally without the sodium/potassium pump in a _____ through the K+ channels and Na+ channels; however it takes energy in the form of ______ to move the Na+ ions out for K+ ions that they move in.
Passive Transport; Active Transport
The transmembrane potential across the cell membrane is approximately ____ in a resting neuron. This is also referred to as the _____ and the cell membrane can be said to be ____.
-70mV; resting potential, polarized
Cells of nerve and muscle tissues have a special ability to alter their transmembrane potential and reverse it momentarily. This results in the inside of the cell becoming positively charged and the outside negatively charged for a short period of time. This process known as _____ the change in potential is called the _____.
depolarization, action potential
Name the 6 steps of polarization.
- 1. membrane at rest
- 2. depolarizing electronic potentials
- 3. K+ moving out rapidly
- 4. no net charge movement
- 5. Na+ moving in rapidly
- 6. Na+ & K+ channels recovering with the aid of ATPase (repolarization)
How long does the whole process of polarization last?
1 millisecond and the resting potential is quickly restored
There is a certain level of depolarization that is required before an action potential can be triggered. What is this called?
Once the stimulus (which may be light, heat, mechanical force, electrical or chemical energy) has caused the neuron to become depolarized above the threshold level, then an ______ is triggered.
A certain threshold exist, but once that threshold is exceeded, whether it is by a gradual or sudden stimulus, the magnitude and duration of the response is the same.
All or none law
If a second stimulus acts upon a neuron in which an action potential is ongoing, then a second action potential will not be produced. The neuron at this stage is unresponsive and is said to be in a ____
The time that it takes for the neuron to be able to generate a second action potential from the start of the first is called the _______.
absolute refractory period
The period between the end of the absolute refractory period (when it is impossible to initiate another action potential) and a return to the resting potential is known as the _____.
relative refractory period
The relative refractory period is the period during which a second action potential can be triggered, although this requires the stimulus to ____ the threshold depolarization.
The point at which the transmission of the nerve impulse from one neuron to another occurs is called the ___.
what is the difference between a synapse and a neuromuscular junction?
- Synapse- between one neuron to another neuron
- Neuromuscular junction- Neuron and muscle fiber
At the synapse, the action potential from the axon of first nerve cell (the presynaptic neuron) is carried across the interstitial space, known as the ______, to the dendrites of the next nerve cell (the postsynaptic neuron)
____ occurs when the two cells are very close together, as the synaptic gap or cleft is small.
When the synaptic gap is large, an impulse in the presynaptic neuron causes the release of a chemical into the gap. Type of transmission?
what is the chemical known as?
Chemical Transmission; Neurotransmitter
Transmission across the synapse occurs primarily by chemical means. What is the most common chemical released?
Neurons releasing Ach are classified as _____. What are the 2 receptors?
Cholinergic; 1. Nicotinic and 2. Muscarinic
What are the 3 Neurotransmitter classifications?
- 1. Amino acids
- 2. Monamines (modified amino acids)
- 3. Polypeptides
Inhibitor of Acetylcholine?
Neurons releasing Nor-epinephrine are classified as_____. What are the 4 receptors?
Adrenergic; 1. Alpha 1 2. Alpha 2 3. Beta 1 4. Beta 2
Nor-epinephrine is active only at the ____ site of the sympathetic system.
The catecholamines can act as ______ of the peripheral and central nervous system.
Inhibitory neurotransmitter of CNS?
Gama- aminobutyric acid (GABA)
Binding GABA to its receptor produces ______ or inhibition.
Excitatory neurotransmitter of CNS?
Receptors for Glutamate are involved with ___ and ____.
memory and learning
Nervous tissue of the brain and spinal cord can be classified as either ____ or ____ matter.
grey or white
a usually clear, colorless, slightly alkaline fluid. similar to plasma but only contains small amount of protein. A few lymphocytes may be present but no red blood cells.
function is to protect the brain and spinal cord by forming a fluid cushion between the delicate nerve tissues and the bones of the skull and vertebral column.
What are the three meninges of connective tissue that surround the brain?
- 1. Dura Mater
- 2. Arachnoid Mater
- -subarachnoid space
- 3. Pia Mater
lies on the surface of the spinal cord
separated from the pia mater by the subarachnoid space via CSF
is the outer meninge and is a thick membrane composed of tough fibrous tissue that lines the inside of the skull forming the periosteum
Where are samples of the CSF taken?
from an enlargement of the subarachnoid space at the base of the skull called the cisterna magna
What 3 parts make up the hindbrain?
- 1. Pons
- 2. Medulla Oblongata
- 3. Cerebellum
The Pons and Medulla Oblongata are both responsible for what two things?
- 1. Heart rate
- 2. respiration
The Cerebellum is responsible for what?
the motor coordination of the body
is continuous with the medulla of the brain. It runs within the protective vertebral column from the Cisterna magna, terminating at the cauda equina.
The spinal cord
a group of nerves that run together in the region of the seventh lumbar vertebrae and the sacral region, resembling a mare's tail.
How many pair of spinal nerves are there?
Each spinal nerve is surrounded by a layer of meningeal dura and has a ____ and a _____.
dorsal and ventral root
The dorsal root is comprised of ______ with their cell bodies located in a cluster or ganglion in the intervertebral foramen.
sensory afferent fibers
The ventral root is comprised of _______ with the cell bodies located in the ventral horn of the grey matter.
motor efferent fibers
includes all other nervous tissue that is not within the brain or spinal cord. It includes all the nerves that pass out from the spinal cord to muscles and organs, as well as those that carry impulses back into the CNS.
carry impulses from the CNS to skeletal muscles
Efferent nerves of the PNS- Somatic Nerves
are responsible for providing feedback to the brain from the skeletal muscle.
Somatic sensory receptors
The majority of the nerves of the PNS are under ______, except in the cases of unconsciousness and reflexes when their action is involuntary.
Nerves of the PNS-Somatic nerves can be further subdivided into ____ and _____ depending upon the part of the body that they innervate.
cranial and spinal nerves
How many pair of cranial nerves are there?
carry impulses to the brain like the sense of smell- Olfactory
Carry impulses from the brain to the effector organ muscles of the eye- Trochlear
carry impulses from the brain to the effector organ and back to the brain.- Trigeminal- motor jaw movement sensory from skin to the facial region
Name the 12 cranial nerves and if sensory, motor, mixed.
- 1. Olfactory-Sensory-smell
- 2. Optic-Sensory-Vision
- 3. Oculomotor-Motor-Eye movement
- 4. Trochlear-Motor-Eye movement
- 5. Trigeminal-Mixed-Sensations from head and teeth
- 6. Abducent- Motor- Eye movement
- 7. Facial-Mixed- Face and scalp movement
- 8. Vestibulocochlear- Sensory- Balance
- 9. Glossopharyngeal- mixed- Tongue movement
- 10. Vagus- mixed- Sensory from GI tract
- 11. Accessory- Motor- Head movement
- 12. Hypoglossal- Motor- Tongue movement
supply the entire musculoskeletal system.
carries sensory nerve fibers into the spinal cord whereas the ventral root carries motor fibers to the musculoskeletal system.
a network of nerve fibers that gives rise to the radial, ulnar, and medial nerves supplying the forelimb in the dog.
is a network of nerve fibers that gives rise to the sciatic, obturator, perineal, pudendal and others.
supraspinatus and infraspinatus muscles. What nerve?
all pectorals including xiphihumeralis. What nerve?
subscapularis muscle. what nerve?
Biceps Brachii and brachialis muscles. What nerve?
teres minor and deltoids. What nerve?
triceps brachii, anconeus and extensors distal to the elbow. What nerve?
flexors distal to the elbow. What nerve?
flexors distal to the elbow not covered by ulnar. What nerve?
Latissimus dorsi. What nerve?
Cutaneous trunci. What nerve?
middle and deep gluteal and tensor fascia latae. What nerve?
Superficial Gluteal, semitendinosus, biceps femoris (in horse). What nerve?
sartorius, quadriceps femoris. What nerve?
adductors, gracilis, pectineus, obturator externus. What nerve?
semimembranosus, biceps femoris, obturator internus, gemelli, quadratus femoris. What nerve?
tibialis cranialis, long digital extensor, peroneus. What nerve?
Gastrocnemius, superficial digital flexor, tibialis caudalis, popliteus. What nerve?
an inborn, involuntary response towards an external stimulus that is mediated by the nervous system
A reflex reaction
Pavlov proved that a dog would salivate when food is placed in the mouth, and as such is an inborn involuntary action, known as a _____.
Pavlov would associate the bell ringing with food and before long dogs would salivate when they heard the bell only. This type of response is called a ________.
Conditioned Reflex Response
Reflex responses can be from ____ or ____ stimuli.
internal or external
8 Reflexes for surgical monitoring.
- 1. Palpebral (blink reflex)
- 2. Pedal
- 3. Ear flick
- 4. Corneal
- 5. Size of Pupil
- 6. Pupillary light
- 7. Heart and Respiratory
- 8. Response to Surgical Stimuli
Two forms of the afferent system of the PNS.
- 1. Somatic sensory neurons
- 2. Visceral sensory neurons
Provide information about the external environment of the animal
Somatic Sensory Neurons
Monitor the internal environment and organs
Visceral Sensory Neurons
Most sensory neurons have specialized reminals or cells known as ___.
3 ways of classification of Receptors
- 1. Where they receive their stimulus
- 2. Structure of the receptors
- 3. Type of stimulus to which the receptor responds
3 places where they receive their stimulus
- 1. Exteroceptors
- 2. Proprioceptors
- 3. Interoceptors
are stimulated by info from the external environment such as touch, sight, smell, hearing, taste, pressure and temperature
monitor movements and position of the skeletal muscles and joints
monitor the internal environment such as the respiratory, digestive, urinary, cardiovascular and reproductive systems. They are also stimulated by deep pressure and pain.
3 types of structure of the receptors
- 1. Unspecialized free nerve endings
- 2. Specialized or encapsulated nerve endings
- 3. Specialized non-neuronal receptor cells
are involved in detecting touch and painful stimuli are located in the skin, muscles, and viscera.
Unspecialized free nerve endings
are located in the dermis of the skin and respond to touch and pressure.
Specialized or encapsulated nerve endings
which are located in the ear and eye, as well as taste buds
Specialized non-neuronal receptor cells
2 Types of stimulus to which the receptor responds.
- 1. Chemoreceptors
- 2. Mechanoreceptors
bunch of nerves outside the spinal cord
Detect chemical changes in the local area around the receptor.
responds to touch and pressure and are predominantly located in the skin
Name 4 Mechanoreceptors
- 1. Thermoreceptors
- 2. Pain receptors or nociceptors
- 3. Electromagnetic receptors
- 4. Proprioceptors
are stimulated by changes in temperature and are located in the skin.
usually triggered by any stimulus that may cause tissue damage or injury.
Pain receptors or nociceptors
are stimulated by light and are found in the retina of the eye
a collective term used to group together all the recptors that relay info about the position of the body and its movements
Some receptors show a reduced response in the presence of a _____.
When the stimulus first occurs the receptor responds fully, however, if the situation persists the level of response declines until the receptors is no longer stimulated. What is this process?
_____ helps to prevent the unnecessary waste of energy responding to stimuli that ate insignificant to the individual.
_____ show little adaptation.
Pain receptors (or nociceptors)
The Autonomic Nervous System controls those parts of the body that are part of an animals ____ actions.
Beta 2 is located ___
Prepares the body for "fight or flight"
Sympathetic Nervous System
Miosis is a _____ response
Mydriasis is a _____ response
The postganglionic neuron with which they synapse in the Sympathetic Nervous system are located in three different locations. What are they?
- 1. Sympathetic chain ganglia or lateral ganglia
- 2. Collateral ganglia
- 3. Adrenal medulla
This ganglia is located on either side of the vertebral column and their neurons affect 4 things. What are they?
- 1. Head
- 2. Body wall
- 3. limbs
- 4. inside the thorax
6 stimulation from the chain ganglia
- 1. Constriction of blood vessels in skin
- 2. Increase blood to skeletal muscles and brain
- 3. release of lipid from fat stores
- 4. Dilation of pupils
- 5. Acceleration of heart rate and strength of cardiac contraction
- 6. Bronchodilation
located anterior to the bodies of the vertebrae and their neurons affect the tissue and organs of the abdomen and pelvis.
5 stimulation from the Collateral Ganglia
- 1. reduced blood flow to visceral organs
- 2. decreased activity of digestive system
- 3. release of glucose from glycogen reserves in the liver
- 4. reduction in the rate of formation of urine
- 5. stimulation of release of lipids from fat stores
The 3rd location of the postganglionic neurons is found in the center of each adrenal gland, and is a _______.
pharmaceuticals that produce sympathetic responses are referred to as being ____.
On stimulation of the preganglionic neurons, acetylcholine is released at the synapse between the preganglionic and postganglionic neurons. These are called ______.
________ are stimulated more by norepinephrine than beta receptors, whereas epinephrine stimulates both type of receptors, equally.
____ receptors are the more common and they generally have an excitatory effect
Alpha 1 has an ____ effect.
_____ receptors generally have an inhibitory effect.
Alpha 2 receptors have an ____ effect
____ receptors cause an increase in metabolism of cells
____ receptors tend to have inhibitory effects
Alpha 1 (adrenergic receptor) acts on smooth muscle to: 4 things
- 1. Constrict blood vessels
- 2. Constrict sphincters in gastrointestinal
- 3. Contract muscles to enlarge pupil
- 4. Contract sphincter of Urethra
Beta 1 acts on cardiac muscle to: 3 things
- 1. sinoatrial node to increase heart beats
- 2. atrioventricular node to speed impulse conduction
- 3. ventricular muscle increasing force of contraction
Beta 2 (adrenergic receptor) acts on smooth muscle to: 4 things
- 1. dilate arteries to skeletal muscle
- 2. relaxes smooth muscles of airways to ease breathing
- 3. relaxes smooth muscles of intestines to ease motility
- 4. liver is acted on to increase glycogeolysis
The major nerve that carries information from most of the parasympathetic division is called the ____ Nerve and supplies all the organs and structures within the thorax and abdomen.
Vagus Nerve (X)
Unlike the Sympathetic system, only one neurotransmitter functions in the parasympathetic system. What is it?
There are 2 receptors for the parasympathetic, no alphas or betas. What are they
- 1. Nicotinic
- 2. Muscarinic
Nicotinic found in 3 places?
- 1. Sympathetic system
- 2. Parasympathetic system
- 3. At the junction between nerves and muscles in the somatic nervous system
Where is Muscarinic found?
in the parasympathetic system at the neuro-effector junction with a few found a the neuro-effector junctions of the sympathetic system
Integration of the two systems- the heart
- If the sympathetic increases
- then the parasympathetic decreases
Integration of the two systems- digestive-
- if the sympathetic decreases
- then the parasympathetic increase
what 2 organs have only sympathetic innervation
- 1. Spleen
- 2. adrenal medulla
The ciliary muscles of the eye are only innervated by the parasympathetic thus causing _____.
The radial muscle of the iris of the eye are stimulated by adrenergic transmissions of the sympathetic system resulting in _____
an enlarged pupil
The medulla and pons are regulated by the ______.
What did Dr Y ask us to write on back of paper under our names?
- Heart stimulated
- Lungs stimulated
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