Nervous System Flashcards
the adjustment of an animal’s response to changes in the environment and the complex linking of the various processes in the body that this response involves
Co-ordination
The Nervous system has 3 major functions:
Sensory
Integration
Motor
*The Nervous system has 3 major functions:
monitors internal & external environment through presence of receptors
Sensory
*The Nervous system has 3 major functions:
interpretation of sensory information (information processing); complex (higher order) functions
Integration
*The Nervous system has 3 major functions:
response to information processed through stimulation of effectors
muscle contraction
glandular secretion
Motor
The ANS consists of 2 divisions:
sympathetic nervous system
parasympathetic nervous system
*Division of ANS
is involved in the stimulation of activities that prepare the body for action, such as increasing the heart rate, increasing the release of sugar from the liver into the blood, and other generally considered as fight-or-flight responses (responses that serve to fight off or retreat from danger).
sympathetic nervous system
*Division of ANS
activates tranquil functions, such as stimulating the secretion of saliva or digestive enzymes into the stomach.
parasympathetic nervous system
*Histology of neural tissue
Two types of neural cells in the nervous system:
Neurons
Neuroglia
*Histology of neural tissue
- For processing, transfer, and storage of information
- Functional units of the nervous system
Neurons
*Histology of neural tissue
For support, regulation & protection of neurons
Neuroglia
*Neuroglia (glial cells)
CNS neuroglia: (4)
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
*Neuroglia (glial cells)
PNS neuroglia: (2)
- Schwann cells (neurolemmocytes)
- satellite cells
*Neuron structure
Stimulated by environmental changes or the activities of other cells
dendrites
*Neuron structure
contains the nucleus and mitochondria, ribosomes and other organelles and inclusions
cell body
*Neuron structure
conducts nerve impulse (action potential) toward synaptic terminals
axon
*Neuron structure
affect another neuron or effector organ (muscle or gland)
synaptic terminal
*Most axons of the nervous system are surrounded by a ______ ______ (myelinated axons)
*The presence of myelin speeds up the transmission of action potentials along the axon
myelin sheath
*Myelin will get laid down in segments (internodes) along the axon, leaving unmyelinated gaps known as ______ __ _______
“nodes of Ranvier”
*Regions of the nervous system containing groupings of myelinated axons make up the _____ ______
“white matter”
____ ______ is mainly comprised of groups of neuron cell bodies, dendrites & synapses (connections between neurons)
“gray matter”
- Spinal cord and brain are wrapped in three protective membranes,
meninges
– Spaces between meninges are filled with
_____________ _____
– Fluid is continuous with that of central canal of spinal cord and the ventricles of the brain
cerebrospinal fluid
- The ______ _____ of the spinal cord and the __________ of the brain are hollow and filled with ____________ _____
The cerebrospinal fluid is filtered from blood and functions to cushion the brain and spinal cord
central canal
ventricles
cerebrospinal fluid
- All vertebrate brains develop from three embryonic regions: ?
- 5 brain regions have formed from the 3 embryonic regions
forebrain, midbrain, and hindbrain
As the brain develops further, the most profound change occurs in the forebrain, which gives rise to the ________
cerebrum
The outer portion of the cerebrum called the ________ ______ surrounds much of the brain
cerebral cortex
The cerebrum develops from the embryonic telencephalon
The cerebrum has right and left
________ __________
cerebral hemispheres
Each cerebral hemisphere consists of a cerebral cortex (gray matter) overlying white matter and basal nuclei
In humans, the cerebral cortex is the _______ and most complex part of the brain
largest
a thick band of nerves that connects the left and right sides of the brain allowing for communication between both hemispheres.
corpus callosum
The primary function of the corpus callosum is to integrate _____, _______ and _________ ____________ between the cerebral cortex on one side of the brain to the same region on the other side.
motor
sensory
cognitive performances
The Diencephalon develops into 3 regions:
epithalamus
thalamus
The hypothalamus
*Diencephalon, 3 regions
includes the pineal gland and generates cerebrospinal fluid from blood
epithalamus
*Diencephalon, 3 regions
is the main input center for sensory information to the cerebrum and the main output center for motor information leaving the cerebrum
thalamus
*Diencephalon, 3 regions
regulates homeostasis and basic survival behaviors such as feeding, fighting, fleeing, and reproducing
hypothalamus
Lobes of the dog brain (6)
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
- Limbic lobe
- Olfactory lobe*
*Functions of the different lobes of the brain
for cognitive functions and control of voluntary movement or activity
frontal lobe
*Functions of the different lobes of the brain
processes information about temperature, taste, touch and movement
parietal lobe
*Functions of the different lobes of the brain
primarily responsible for vision.
occipital lobe
*Functions of the different lobes of the brain
processes memories, integrating them with sensations of taste, sound, sight and touch
temporal lobe
*Functions of the different lobes of the brain
emotions, memories, and arousal (or stimulation)
limbic lobe
- a complex set of structures that lies on both sides of the thalamus, just under the cerebrum.
- primarily responsible for emotions, and has a lot to do with the formation of memories, and sexual satisfaction
Limbic system
limbic from the latin word, ? which means “border”
“limbus”
*Function of the limbic system
B. Low threshold for seizure activity; stimulation of the hippocampus or amygdala in cats induces __________ ________ characterized by abnormal behavior (fear/rage) followed by tonic/clonic convulsions.
“psychomotor” convulsions
- a small part of the brain located just below the thalamus on both sides of the third ventricle. It sits just inside the two tracts of the optic nerve, and just above the pituitary gland.
Hypothalamus
The hypothalamus is one of the busiest parts of the brain, and is mainly concerned with ___________
homeostasis
*Sources of inputs of the hypothalamus
(From the _____ nerve, it gets information about blood pressure and the distension of the gut (that is, how full your stomach is).)
vagus
*Sources of inputs of the hypothalamus
From the _________ ___________ __ ___ _________, it gets information about skin temperature.
reticular formation in the brainstem
*Sources of inputs of the hypothalamus
From the _____ nerve, it gets information about light and darkness.
optic
*Sources of inputs of the hypothalamus
From unusual _______ lining the ventricles, it gets information about the contents of the cerebrospinal fluid, including toxins that lead to vomiting.
neurons
*Sources of inputs of the hypothalamus
From the other parts of the limbic system and the _________ nerves, it gets information that helps regulate eating and sexuality.
olfactory
*Sources of inputs of the hypothalamus
It also has some receptors of its ___, that provide information about ion balance and temperature of the blood.
own
The hypothalamus sends instructions to the rest of the body in two ways:
autonomic nervous system
pituitary gland
This allows the hypothalamus to have ultimate control of things like blood pressure, heartrate, breathing, digestion, sweating, and all the sympathetic and parasympathetic functions.
autonomic nervous system
It is neurally and chemically connected to the pituitary, which in turn pumps hormones called releasing factors into the bloodstream.
pituitary gland
- consists of two “horns” (Ammon’s horn) that curve back from the amygdala
- it converts short-term memory to long term memory
Hippocampus
*Hippocampus
very important in the diagnosis of rabies:
NEGRI BODIES
- two almond-shaped masses of neurons on either side of the thalamus at the lower end of the hippocampus
Amygdala
it provides a pathway from the thalamus to the hippocampus, seems to be responsible for focusing attention on emotionally significant events, and for associating memories to smells and to pain.
Cingulate gyrus
consists of dopamine pathways that seem to be responsible for pleasure.
Ventral tegmental area of the brain stem
lie over and to the sides of the limbic system, and are tightly connected with the cortex above them. These are responsible for repetitive behaviors, reward experiences, and focusing attention.
Basal ganglia
part of the frontal lobe which lies in front of the motor area, is also closely linked to the limbic system. Involved in thinking about the future, making plans, and taking action.
Prefrontal cortex
- Puppies are born with both ____ and ____ sealed shut, leaving the sense of _____ as their only guide during their first weeks of life. A puppy won’t typically gain his hearing until __ weeks after birth, while the eyes will begin to open around 2 weeks – even then, vision is limited to simple changes in light and movement. It can take up to 2 months after being born for a puppy’s eyes to become fully developed.
eyes
ears
smell
3
- important for coordination and movement
- It is also involved in learning and remembering motor skills
The Cerebellum
*Cerebellar Ataxia in Dogs and Cats
When the cerebellum is damaged, it can result in a loss of ___(3). It can also sometimes cause cognitive impairment.
coordination
balance
motor function control
coordinates and conducts information between brain centers
brainstem
The brainstem has three parts:
midbrain
pons
medulla oblongata
*Parts of the brainstem
contains centers for receipt and integration of sensory information
midbrain
*Parts of the brainstem
regulates breathing centers in the medulla
pons
*Parts of the brainstem
contains centers that control several functions including breathing, cardiovascular activity, swallowing, vomiting, and digestion
medulla oblongata
- Runs through the vertebral canal of the
vertebral column
The Spinal Cord
Functions of spinal cord
- Sensory and motor innervation of entire body inferior to the head through the spinal nerves
- Two-way conduction pathway between the body and the brain
- Major center for reflexes
The spinal cord can be divided to several regions:
- cervical (C1-C6)
- cervicothoracic (C7-T2)
- thoracolumbar (T3-L3)
- lumbosacral (L3-S2)
- sacral (S3 onwards)
*Structure and function of spinal cord
which has axons and white matter
marginal layer
*Structure and function of spinal cord
which contains cell bodies and grey matter
mantle
3 Structure and function of spinal cord
- marginal layer
- mantle
- spinal canal
consists of the nerves and ganglia outside the brain and spinal cord.
Peripheral nervous system (PNS)
The main function of the PNS is to ___ essentially serving as a relay between the brain and spinal cord and the rest of the body.
to connect the
CNS to the limbs and organs,
Unlike the ___, the PNS is not protected by the vertebral column and skull, or by the blood–brain barrier, which leaves it exposed to toxins and mechanical injuries.
CNS
2 Divisions of PNS
somatic nervous system,
autonomic nervous system
*Division of PNS
the cranial nerves are part of the PNS with the exception of the optic nerve (cranial nerve II), along with the retina.
somatic nervous system,
*Division of PNS
is an involuntary control of smooth muscle and glands.
autonomic nervous system
The connection between CNS and organs allows the system to be in two different functional states:
sympathetic
and parasympathetic.
they emerge through foramina or fissures in the cranium and are covered by tubular sheaths derived from the cranial meninges.
Like spinal nerves, these are bundles of sensory or motor fibers that innervate muscles or glands; carry impulses from sensory receptors, or show a combination of these fiber types.
cranial nerves
Function: Special sensory (special visceral afferent) that is, the special sense of smell.
Olfactory Nerve (CN I)
Function: Special sensory (special somatic afferent) that is, the special sense of vision.
Optic Nerve (CN II)
Functions: Somatic motor (general somatic efferent) and visceral motor (general visceral efferent parasympathetic).
is the chief motor nerve to the ocular and extraocular muscles. It emerges from the midbrain, pierces the dura lateral to the sellar diaphragm roofing over the hypophysis, and then runs through the roof and lateral wall of the cavernous sinus.
Oculomotor Nerve (CN III)
Functions: Somatic motor (general somatic efferent) and proprioceptive to one extraocular muscle (superior oblique).
is the smallest cranial nerve.
Trochlear Nerve (CN IV)
The largest cranial nerve
Trigeminal Nerve (CN V)
*Trigeminal Nerve (CN V)
*Opthalmic division – sensory
the major sensory nerve to the horn of the small ruminants
INFRATROCHLEAR NERVE
*Trigeminal Nerve (CN V)
*Opthalmic division – sensory
supplies sensation to the cornea
LONG CILIARY NERVE
*Trigeminal Nerve (CN V)
*Maxillary division – sensory
the major sensory nerve to the horn of the ox
CORNUAL NERVE
*Trigeminal Nerve (CN V)
*Maxillary division – sensory
supplies sensation to the middle part of the chin (infraorbital foramen)
INFRAORBITAL NERVE
*Trigeminal Nerve (CN V)
*Mandibular division – mixed nerve (sensory and motor)
supplies sensation to the chin (mental foramen)
MENTAL NERVE
Function: Somatic motor to one extraocular muscle (lateral rectus).
traverses the common tendinous ring as it enters the orbit, running on and penetrating the medial surface of the lateral rectus
Abducent Nerve (CN VI)
Functions: Sensory (special visceral afferent and general somatic afferent), motor (branchial motor or special visceral efferent), and parasympathetic (general visceral efferent). It also carries proprioceptive fibers from the muscles it innervates.
Facial Nerve (CN VII)
*Facial Nerve (CN VII)
Some fibers from the geniculate ganglion supply a small area of the skin of the concha of the auricle, close to external acoustic meatus.
General Sensory
*Facial Nerve (CN VII)
Fibers carried by the chorda tympani join the lingual nerve to convey taste sensation from the anterior two thirds of the tongue and soft palate
Taste (Special Sensory)
Functions: Special sensory (special somatic afferent) that is, special sensations of hearing and equilibrium.
Vestibulocochlear Nerve (CN VIII)
*Vestibulocochlear Nerve (CN VIII)
is concerned with equilibrium.
vestibular nerve
*Vestibulocochlear Nerve (CN VIII)
is concerned with hearing
cochlear nerve
Functions: Sensory (general somatic afferent, special visceral afferent, general visceral afferent), motor (special visceral efferent), and parasympathetic (general visceral efferent) for derivatives of the 3rd pharyngeal arch.
Glossopharyngeal Nerve (CN IX)
CN IX follows the _______________, the only muscle the nerve supplies, and passes between the superior and the middle constrictor muscles of the pharynx to reach the oropharynx and tongue. It contributes sensory fibers to the pharyngeal plexus of nerves.
stylopharyngeus
Functions: Sensory (general somatic afferent, special visceral afferent, general visceral afferent), motor (special visceral efferent), and parasympathetic (general visceral efferent).
Vagus Nerve (CN X)
The term vagus is derived from the Latin word vagari meaning _________.
wandering
Functions: Motor to the striated sternocleidomastoid and trapezius muscles.
Accessory Nerve (CN XI)
Functions: Motor (general somatic efferent) to the intrinsic and extrinsic muscles of the tongue (G. glossa) styloglossus, hyoglossus, and genioglossus.
For vocalization and swallowing
Hypoglossal Nerve (CN XII)
- under voluntary control, and transmits signals from the brain to end organs such as muscles.
– Cervical spinal nerves (C1–C4)
– Brachial plexus (C5–T1)
– Lumbosacral plexus (L1–Co1)
Somatic Nervous System
*Cervical spinal nerves (C1–C4)
is a nerve essential for our survival which arises from nerve roots C3, C4 and C5. It supplies the thoracic diaphragm, enabling breathing.
phrenic nerve
The last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1, combine to form the brachial plexus, or plexus brachialis, a tangled array of nerves, splitting, combining and recombining, to form the nerves that subserve the upper-limb and upper back.
Brachial plexus
- The anterior divisions of the lumbar nerves, sacral nerves, and coccygeal nerve form the lumbosacral plexus
- The first lumbar nerve being frequently joined by a branch from the twelfth thoracic
Lumbosacral plexus
