A & P Exam 3 Flashcards
Microscopic nerve cells or nerve fibers are also called
neurons
Where are neurons found?
Brain, spinal cord, peripheral nerves
What is the basic functional unit of the nervous system?
Neurons
Neurons have a high requirement for what?
oxygen
What do neurons use for energy?
Glucose
Neurons cannot reproduce but can regenerate cell processed if the cell ____ remains intact
body
These cells structurally and functionally support and protect the neurons.
Neuroglia or glial cells
There are __X as many glial cells as there are neurons.
10X
Are glial cells directly involved in the transmission of information or impulses through the nervous system?
No
The central cell body of a neuron is also called (2 names)
soma or perikaryon
This nerve cell process receives stimuli from other neurons and conducts the stimuli to the cell body. Short, numerous, multi-branched projections extending from the cell body.
Dendrites
This nerve cell process conducts nerve impulses away from the cell body toward another neuron or an effector cell. They are single, long processes.
Axons
These nerve cell processes may be modified into sensory receptors that receive stimuli such as heat, cold, touch, pressure, stretch, or other physical changes from inside or outside the body.
Dendrites
A cell that does something when stimulated such as a muscle or gland cell.
Effector cell
Axons may be covered with a fatty substance that appears white.
Myelin
Nervous tissue containing many myelinated axons is called
white matter
Nervous tissue made up largely of neuron cell bodies appears as
gray matter
Do myelinated axons conduct impulses faster or slower than unmyelinated ones?
Faster
Cell membrane of glial cells tightly wrapped around the axon is called a
myelin sheath
Glial cells located in the brain and spinal cord are called
oligodendrocytes
Glial cells in the nerves outside the brain and spinal cord are called
Schwann cells
Gaps between adjacent glial cells on a myelin sheath are called
Nodes of Ranvier
A group of axons outside the CNS
nerve
A group of axons inside the CNS
Tract
A collection of cell bodies located outside the CNS
Ganglion
A cell body that is outside the CNS in a ganglion
sensory neuron
A cell body entirely within the CNS
Interneuron
A cell body in the spinal cord, and axon outside the CNS is called
motor neuron
Cell bodies are located in the ____ (sensory) or in the _____ (motor).
Ganglion
Gray matter
Does a nerve contain cell bodies?
No
Within a nerve, each fiber (axon) is surrounded by a connective tissue sheath called an ______, which insulates it from the other neurons adjacent to it.
endoneurium
Groups of fibers are bound by a coarser connective tissue, called the
perineurium
Finally, all fascicles are bound together by a tough, fibrous connective tissue sheath called the
epineurium
Blood vessels and lymphatic vessels serving the fibers also travel within the
nerve
The brain and spinal cord make up the
Central Nervous System (CNS)
This nervous system consists of nerves that link the CNS with the rest of the body
Peripheral nervous system (PNS)
Cranial nerves originate directly from the
brain.
Spinal nerves emerge from the
spinal cord
The PNS is separated into what?
Somatic nervous system and Autonomic nervous system
Voluntary nervous system with input from sense organs and output to skeletal muscles is called the
Somatic nervous system
Involuntary nervous system with input from internal receptors and output to smooth muscles and glands is called
Autonomic nervous system
The autonomic nervous system is divided into
Sympathetic and Parasympathetic motor systems
Autonomic motor system that initiates “fight or flight” responses. Involves neurotransmitter noradrenaline, so also called Adrenergic System.
Sympathetic Motor System
Autonomic motor system in charge of relaxing responses. Involves neurotransmitter acetylcholine, so also called Cholinergic System.
Parasympathetic Motor system
The sympathetic motor system is also known as
Adrenergic System
The parasympathetic motor system is also known as
Cholinergic system
Somatic motor nerves send impulses to
skeletal muscle
This nervous system is in charge of functions that determine the relationship of the animal to the outside world.
Somatic
This nervous system is in charge of functions that relate to the internal environment of the animal.
Autonomic
Autonomic motor nerves send impulses to (3)
smooth muscle, cardiac muscle, and glands
An animal turning its head in response to its name being called is an example of autonomic or somatic?
Somatic
Slowing of the heart rate in response to an increased blood pressure is an example of autonomic or somatic?
Autonomic
These nerves, also called sensory nerves, conduct impulses toward the CNS. They conduct sensations from sensory receptors in the skin and other locations in the body to the CNS.
Afferent nerves
These nerves, also called motor nerves, conduct impulses away from CNS towards muscles and other organs.
Efferent nerves
This type of nerve causes muscle contraction and movement among other things. They also cause glands to excrete a substance.
Efferent nerves
Cranial and spinal nerves in the PNS and nerve tracts (bundles of axons) in the CNS may carry which type of nerve fibers?
Sensory and motor
Afferent nerves are also called
sensory nerves
Efferent nerves are also called
motor nerves
Perception of pain from an injection of antibiotics is controlled by
Somatic, sensory
Conscious movement of a forelimb is controlled by
Somatic, motor
Perception of the amount of acidity present in the duodenum is controlled by
Autonomic, sensory
Slowing of heart rate in response to an increased blood pressure is controlled by
Autonomic, sensory: sensing the increased blood pressure
Autonomic, motor: slowing the heart rate
Constriction of blood vessels in the skin in response to cold temps is controlled by
Somatic, sensory: sensing cold temps
Autonomic, motor: constricting the vessels
What are the 4 different areas of the brain?
cerebrum, cerebellum, diencephalon, brain stem
Largest part of the brain in domestic animals. Area responsible for higher-order behaviors (learning, intelligence, awareness). Contains corpus callosum, gray and white matter.
Cerebrum
Ear shaped area in the cerebrum is called the
corpus callosum
Cerebral cortex; outer layer of the brain made up mainly of neuron cell bodies
Gray matter
Made up mainly of myelinated axons; fibers beneath the cortex and corpus callosum (fibers that connect the 2 halves of the cerebral cortex).
White matter
Folds or hills in the cerebral hemispheres.
Gyri (gyrus)
Shallow grooves separating the gyri. Divides the cerebral hemispheres into lobes.
Sulci (sulcus)
Deep grooves separating the gyri are called
Fissures
Prominent fissure that divides the cerebrum into right and left cerebral hemispheres.
Longitudinal fissure
The 2nd largest component of the brain. Located just caudal to the cerebrum. Area of the brain responsible for coordinated movement, balance, posture, and complex reflexes.
Cerebellum
Feline panleukopenia due to viral infection of the dam during pregnancy can cause a undergrowth of the cerebellum called
congenital cerebellar hypoplasia
Passageway between brain stem and cerebrum. Contains the thalamus, hypothalamus and pineal body(*different from what book says).
Diencephalon
Located in the diencephalon. Acts as a relay station for regulating sensory inputs to the cerebrum
Thalamus
Located in the diencephalon. Interface between the nervous system and the endocrine system.
Hypothalamus
Located in the diencephalon. Produces serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal fuctions.
Pineal body/gland
This structure is associated with the diencephalon. It is the endocrine “master gland” that regulates hormone production and release.
Pituitary gland
The connection between the rest of the brain and the spinal cord. Composed of the medulla oblongata, pons, and midbrain. Area responsible for basic support functions (heart, respiration, swallowing, vomitting). Many of the cranial nerves originate from this area of the brain.
Brain stem
A set of connective tissue layers that surround the brain and spinal cord. Contains blood vessels, fluid, and fat. Supply nutrients and O2 to the superficial tissues of the brain and spinal cord. Provides some cushioning and distribution of nutrients of the CNS.
Meninges
What are the 3 tissue layers of the meninges?
Dura mater, arachnoid, pia mater
The tough, fibrous outer tissue layer of the meninges, just deep to the skull bone.
Dura mater
The delicate, spiderweb-like tissue layer of the meninges, deep to the subdural space.
Arachnoid
The very thin tissue layer of the meninges that lies directly on the surface of the brain and spinal cord. Deep to the subarachnoid space.
Pia mater
Fluid between layers of the meninges (subarachnoid space) and in ventricles (inside the brain) and the central canal (of spinal cord). Provides cushioning fuctions, regulation of autonomic functions such as respiration and vomiting, diagnostic tool.
Cerebrospinal fluid (CSF)
Where is CSF located (3)?
Subarachnoid space, ventricles (brain), and central canal (spinal cord)
What is the procedure called when collecting CSF from subarachnoid space between the atlanto-occipital joint or L5-L6?
CSF tap
Contrast injected into the subarachnoid space at L5-L6 is called
myelogram
A local anesthetic injected in the epidural space is called
epidural
Space between the dura mater and surrounding bone is called
epidural space
There is no epidural space in the skull because the dura mater is fused with the
periosteum
The restriction of large molecules to the vascular space is the result of tight junctions between neighboring capillary endothelial cells in the brain. This is called the
blood-brain barrier
This prevents many drugs, proteins, ions, and other large molecules from readily passing from the blood into the brain.
blood-brain barrier
This type of junction, located in the capillaries of the blood-brain barrier are not found in capillaries elsewhere in the body.
Tight junctions
In addition to tight junctions, the blood-brain barrier also contains processes of ____ cells that surround the outside of capillary endothelial cells.
glial
A protein found on endothelial cells impedes transport of various drugs from the capillaries to the brain. Approximately 35% of collies have a genetic mutation creating a non-functional protein here. This allows for ivermectin doses that would normally be blocked from the CNS to gain access to it. What is this condition called?
Ivermectin toxicity
How many cranial nerve pairs originate directly from the brain stem?
12 (numbered in Roman numerals)
What are the 2 cranial nerves that do not originate from the brain stem?
Olfactory and optic
Each cranial nerve may contain axons of motor neurons, axons of sensory neurons, or
combinations of both
The outer portion of the spinal cord that consists of white matter and surrounds the gray matter.
Cortex
The central part of the spinal cord composed of gray matter.
Medulla
This structure of the spinal cord contains the residual embryonic neural tube.
Central canal
The dorsal nerve roots contain ____ fibers.
sensory
The ventral nerve roots contain ___ fibers.
motor
The dorsal and ventral nerve roots emerge from the spinal cord between each pair of adjacent
vertebrae
Neurons in gray matter of the spinal cord that forward sensory nerve impulses to brain or other parts of the spinal cord.
Dorsal horns
Neurons in gray matter of the spinal cord that forward motor (efferent) nerve impulses to the spinal nerves
Ventral horns
When a neuron is not being stimulated, it is in a
resting state.
Difference in electrical charge across a neuronal membrane. The inside of the neuron is more negatively charged than the outside.
Resting membrane potential
Neuron receives external stimulus. Sodium channel opens on neuron cell membrane. Sodium ions flow into cell by passive diffusion. These are steps associated with
depolarization
Sodium channels close; K+ channels open; K+ diffuses out of the cell; the net negative charge in the cell is restored; K+ channels close. These are steps associated with
repolarization
The Na+ & K+ ions are now on opposite sides from where they began. Sodium-potassium pumps moves sodium & potassium ions back to their original sides. Resting state restored. These are steps associated with
repolarization
Specialized molecule that helps maintain cell resting state. It is an antiport since it pumps ions in different directions.
Sodium-potassium pump
The Na+-K+ pump pumps how many Na+ ions from inside the neuron to the outside?
3
The Na+-K+ pump pumps how many K+ ions from outside the neuron to the inside?
2
The stimulus must be sufficient to make the neuron respond and cause complete depolarization. This is known as the
threshold stimulus.
The neuron depolarizes to its maximum strength or not at all. This principle is known as the
all or nothing principle
The initial stimulus causes a spreading wave of opening sodium channels to travel along the cell membrane of the entire neuron. This is called the wave of depolarization, conduction of action potential, or
nerve impulse
Time period during which a neuron is insensitive to additional stimuli is called the
refractory period.
What are the 2 refractory periods?
Absolute and relative
The refractory period during sodium influx and early potassium outflow. Cell is still in depolarization/early repolarization. The cell cannot respond to stimuli.
Absolute refractory period
The refractory period during end of the repolarization period. It may be possible to stimulate another depolarization if stimulus is very large.
Relative refractory period
Myelin sheath prevents Na+ ions from flowing across the neuronal cell membrane. Depolarization wave in myelinated axons skips from 1 node of Ranvier to the next. Rapid means of conducting an action potential. This is called the
Saltatory conduction
Immune system destroys the myelin covering axons resulting in delayed transmission nerve impulses known as
Multiple Sclerosis
