Anatomy and Physiology II
What kind of information of the dorsal nerve roots of the spinal cord carry? The ventral nerve roots?
Dorsal: sensory/afferent fibers Ventral: motor/efferent fibers
some of the more important neurotransmitters include the following:
acetylcholine, norepinephrine, gamma-aminobutyric acid (GABA), dopamine, enkephalins, serotonin
nociceptors are not found in which organ
brain
The central nervous system consists of
brain and spinal cord and their associated structures
norepinephrine, dopamine, and epinephrine belong to a group of neurotransmitters known as
catecholamines
the reflective tapetum lucidum is formed on the
choroid
which stucture contains the muscles that adjust the shape of the lens of the eye
ciliary body
the somatic nervous system carries out
conscious activities, such as walking, eating and so on
The nervous system is the body's
control center
which causes the greatest degree of light refraction in the eye
cornea
the _____connects the two halves of the brain
corpus callosum
What is the parasympathetic nervous system known as?
cranial-sacral system
What is the resting membrane potential?
difference in electrical charge across neuronal membrane
the function of mucus in the nasal cavities is to
dissolve odor molecules for detection by the receptor cells
the autonomic nervous system perfroms functions that
don't require conscious thought, such as breathing, blood pressure, and heart rate
What kind of information do the dorsal horns and ventral horns of the spinal cord carry?
dorsal horns: forward sensory(afferent) nerve impulses to brain or other parts of spinal cord ventral horns: forward motor(efferent) nerve impulses to the spinal nerves
what is the test for a proprioception deficit
flip over a foot while the animal is standing and see if the animal corrects the position
Why are the general senses referred to as general?
general senses are distributed generally throughout the body
What is the difference between grey matter and white matter besides color?
grey matter is found in the outer layer of the brain, the cerebral cortex; where the most neuron cell bodies and where most of the nerve impulse are start, white matter are the fibers beneath the cortex and corpus callosum (fibers that connect the two halves of the cerebral cortex)
What kinds of stimuli can neurons detect?
hot, cold, touch, pressure, stretch or other physical changes from the inside or outside the body
central temperature receptors that monitor the body's internal termperature are located within which structure of the brain
hypothalamus
reflexes
involuntary motor movements initiated by specific sensory input
what is true of gray matter
it makes up the oter tissue layer in the brain
what is the correct pathway by which sound is transmitted between the ossicles of the middle ear
malleus, incus, stapes
Why can we administer ivermectin to mammals if ivermectin works as an inhibitor to parasites?
mammals have a blood-brain barrier that prevents ivermectin from reaching target receptors on cells within the brain; however, insects and parasites do not have such a barrier, so the ivermectin can readily reach target receptors throughout the nervous system
what supplies a rich network of blood vessels that supply nutrients and oxygen to the superficial tissues of the brain and spinal cord
meninges
Efferent nerves are also called _________ and they carry information _________ the CNS.
motor nerves;away from
the area of the brain through which sensory signals pass to the cerebrum is called the
thalamus
ipsilateral reflex refers to
reflex where the stimulus and response are both on the same side of the body
Where are special senses located?
All located in the head
How is core temperature measured in a clinical setting?
By using a rectal thermometer
What ion must enter the terminal bouton for neurotransmitters to dump into the synaptic cleft?
Calcium ions
What are the three parts of a neuron?
Central cell body (soma), dendrites, and axons
What are the four parts of the brain? What is the function of each part?
Cerebrum: receives and interprets sensory information, initiates conscious (voluntary) nerve impulses to skeletal muscles, and integrates neuron activity that is not normally associated with communication, expression of emotional responses, learning, memory and recall, and other behaviors associated with conscious activity Cerebellum: allows the body to have coordinated movement, balance, posture, and complex reflexes Diencephalon:serves as a nervous system passageway between the primitive brain stem and the cerebrum Brain stem: maintain basic support functions of the body, operates at the subconscious level. heavily involved in autonomic control functions related to the heart, respiration, blood vessel diameter, swallowing, and vomiting.
What neuron process receives information and which sends out information?
Dendrites: receive stimuli from other neurons and conduct the stimulus to the cell body Axons: conduct nerve impulses away from the cell body
Explain depolarization
Depolarization is when the neuron receives external stimulus, sodium channel opens on neuron cell membrane, sodium ions flow into cells by passive diffusion
What is the difference between an excitatory and inhibitory neurotransmitter?
Excitatory neurotransmitters: usually cause an influx of sodium so that the postsynaptic membrane moves toward threshold Inhibitory neurotransmitters: move the charge within the postsynaptic cell further away from threshold (makes it more negative)
What structures are located in the external ear, middle ear, and inner ear?
External ear: Pinna, external auditory canal, and tympanic membrane Middle ear: Ossicles, eustachian tube Inner Ear: Cochlea, organ of Corti
How are smell receptors stimulated?
Hair-like processes project up from olfactory cells into the mucous layer that covers the nasal epithelium, nerve impulses are generated, travel to the brain, and are interpreted as particular smells
What is the refractory period and what are the two types of refractory period
It is a time period during which a neuron is insensitive to additional stimuli; absolute refractory period and relative refractory period
Why is saltatory conduction important to large animals?
It makes processes such as vision and fine motor control possible in larger animals
In what order are the middle ear ossicles? What structures do the two end bones rest upon?
Malleus->Incus->Stapes; the tensor tympani and the stapedius
What are the general types of stimuli and give examples of each.
Mechanical: touch, hearing, balance Thermal:hot and cold Electromagnetic: vision Chemical: taste and smell
What are the basic functional units of the nervous system and what is their support group?
Neurons; Neuroglia (glial cells)
What are neurotransmitters and how do they continue a nerve impulse?
Neurotransmitters: a chemical released by the presynaptic neuron; when the nerve impulse reaches the terminal bouton, and crosses the synaptic cleft between two neuron cells with the assistance of neurotransmitters
What is proprioception? How can this be achieved?
Sense of body position and movement, knowing where body parts are at any given time, operates at any given time
What is the olfactory sense?
Sense of smell
What is the difference between the autonomic nervous system and the somatic nervous system?
Somatic: actions under voluntary control Autonomic: controls and coordinates involuntary functions
What is the sodium-potassium pump and how does this explain why even a small imbalance of electrolytes can have detrimental effects to the body?
Specialized molecule that helps a cell maintain its resting state; imbalance will affect depolarization and repolarization
What is the "all-or-nothing principal" and how does it relate to stimuli?
Stimulus must be sufficient/strong enough to make the neuron respond and cause complete depolarization, it either completely completes the cycle or doesn't do it at all
Where are superficial and central temperature receptors located?
Superficial: in the skin Central: hypothalamus
What is the difference between the CNS and the PNS?
The CNS is composed of the brain and the spinal cord, which is found withing the central axis of the body; whereas the PNS is made up of those components of the nervous system that extend away fromt he central axis outward, toward the periphery of the body
How are vibrations carried from the tympanic membrane to the cochlea?
The ossicles link the tympanic membrane with the cochlea of the inner ear, act as a system of levers that transmit sound wave vibrations from the tympanic membrane to the cochlea
What is gustatory sense?
The sense of taste
How are neurotransmitters recycled? Which molecules break down acetylcholine and norepinephrine?
They are broken down by certain enzymes; acetylcholinesterase breaks down acetylilchone amd morepinephrine is broken down by the enzyme monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT).
How do animals react to pain?
They can hide pain very well, some are very sensitive and become stressed easily whereas others are very stoic and show no issues until the problem is severe.
What is the difference between touch and pressure?
Touch: tactile sense, sensation of something being in contact with the surface of the body Pressure: the sense of something pressing on the body surface
What are the four steps of the pain process?
Transduction: conversion of a painful stimulus into a nerve impulse Transmission: conduction of nerve impulse to CNS Modulation: change nerve impulse, amplify or suppress Perception: conscious awareness of painful stimuli
What is the resting state of a neuron? Is it really resting?
When a neuron is not being stimulated; No because it is still working to maintain its resting state
Touch and pressure often operate at a nearly unconscious level. When do they operate at a conscious level?
When the contact is abrupt or severe.
Where are the structures for the auditory sense located? (which bone)
Within the temporal bones of the skull
recptors
nerve endings that detect changes in the environment
What are spinal nerves?
nerves of the peripheral nervous system that originate from the spinal cord;divided into dorsal nerve roots (sensory/afferent fibers) and ventral nerve roots (motor/efferent fibers)
calls that support neurons structurally and functionally are called
neuroglia
the basic structural and functional unit of the nervous system is the
neuron, or nerve cell
the third eyelid found in some species is referred to by which name
nictitating membrane
Can a neurotransmitter bind to any receptor on a postsynaptic membrane?
no, just like a lock requires a specific key, the postsynaptic membrane receptors are very specific about which neurotransmitters they will bind.
Which cells attribute to the myelin sheath?
oligodendrocytes in the brain and spinal cord, Schwann cells in the nerves outside the brain and spinal cord
Where are chemical taste receptors located?
on the tongue in the oral cavity, also found in the lining of the mouth and pharynx
What are nociceptors?
pain receptors
What types of organs are associated with visceral sensations?
pertaining soft internal organs: like the GI tract and portions of the urinary system
a reflex arc commonly used to assess the depth of anesthesia is the ______reflex
pupillary light
rotation of the head is detected primarily by the
semicircular canals
auditory sense
sense of hearing
olfactory sense
sense of smell
gustatory sense
sense of taste
Afferent nerves are also called________ and they carry information __________ the CNS
sensory nerves;toward
2 important types of neurons are
sensory neurons and motor neurons
What are the nodes of Ranvier?
small gaps in the myelin sheath
Explain repolarization
sodium channels shut, potassium channels open, potassium diffuses out of the cell, as this stage ends the Na and K ions revert to their original side, resting stage is restored
What is the external auditory canal?
soft membrane-lined tube
What are cranial nerves?
special set of 12 nerve pairs in the PNS that originate directly from the brain.
which receptors are involved with the proprioception sense
stretch receptors in the muscles, tendons and ligaments
What type of stimulus is associated with visceral sensations?
stretch receptors, hunger and thirst
What is the duty of the meninges?
supply nutrients and oxygen to the superficial tissues of the brain and spinal cord; provide some cushioning and distribution of nutrient for the CNS
motor neurons carry instructions from
the brain to the muscles, causing them to move.
depolarization is
the change in membrane potential that occurs when a nerve is stimulated
the peripheral nervous system is comprised of
the nerves traveling from the brain or spinal cord to the target organs and back
repolarization is
the reestablishment of normal resting membrane potential
What is a terminal bouton?
the slightly enlarged bulb on each end of telodendron, contains mitochondria and neurotransmitters
What is the eustachian tube?
the tube that connects the middle ear cavity with the pharynx
what is a visceral sense
thirst
The sympathetic nervous system is also known as the ___________ because its nerves emerge from the thoracic and lumbar vertebral regions.
thoracolumbar system
What does saltare mean?
to leap
the tactile sense is the sense of
touch
sensory neurons carry signals of
touch, taste, etc. to the brain
the primary purpose of a neuron is to
transmit an electrical signal that acts either to signal other neurons or to cause a change in a target organ, such as a muscle or gland
The tympanic membrane ________ when struck by sound wave vibrations.
vibrates
Conduction of the action potential can also be described as a _______ of depolarization or nerve ________,
wave;impulse
Where can nociceptors be found?
widely distributed sensory receptors inside and on the surface of the body, found almost everywhere, range from simple, free nerve endings that respond to intense stimuli of all types, to more specialized structures that detect mechanical forces, temperature, etc