Exam 2 Flashcards
The ___ and ___ are both involved in amplifying sound waves.
A. Pinna, Ear bone
B. Tympanic membrane, Ear bone
C. Pinna, Tympanic membrane
D. Auditory canal, Tympanic membrane
B. Tympanic membrane, Ear bone
A dog has more than ___ olfactory receptors in its nose, while humans have only 5 million.
A. 5 million
B. 220 million
C. 1 billion
D. 100 thousand
B. 220 million
Taste is an extremely important sense for dogs. Is this statement true or false?
False
Which sequence of events below is in the correct order in regards to the process of hearing (note some steps may be missing in this process)?
A. >The action potentials are then transmitted as nerve impulses to the auditory cortex of the brain through the vestibulocochlear nerve»_space; The sound waves are directed towards the ear canal by the pinna»_space; The vibrations are picked up by the malleus on the other side >
B. >The vibrations are picked up by the malleus on the other side»_space; The sound waves are directed towards the ear canal by the pinna»_space; The action potentials are then transmitted as nerve impulses to the auditory cortex of the brain through the vestibulocochlear nerve >
C. >The sound waves are directed towards the ear canal by the pinna >The vibrations are picked up by the malleus on the other side»_space; The action potentials are then transmitted as nerve impulses to the auditory cortex of the brain through the vestibulocochlear nerve
C. >The sound waves are directed towards the ear canal by the pinna >The vibrations are picked up by the malleus on the other side»_space; The action potentials are then transmitted as nerve impulses to the auditory cortex of the brain through the vestibulocochlear nerve
An organ in dogs involved in detecting pheromones is called the ___ organ.
A. mechano
B. vomeronasal
C. vestibular
D. corpuscular
Dogs are scotopic, which means that
A. they are trichromatic
B. they have a low sensitivity to light, but have a high color sensitivity
C. they have a high sensitivity to light, but have a low color sensitivity
D. have more numerous rod and cone cells compared to humans
C. they have a high sensitivity to light, but have a low color sensitivity
The ___ cells are responding to color and the ___ cells are responding to the brightness/dimness of the light.
A. iris, cone
B. cone, rod
C. cornea, rod
D. rod, cone
B. cone,rod
The same cranial nerve transmits the sense of taste to the brain, irregardless of the location (front, sides, or back) of the taste receptor on the surface of the tongue. True or false?
False
___ taste is typically associated with toxins, which can be found in grasses and plants.
A. Umami
B. Bitter
C. Salty
D. Sweet
B. Bitter
Unlike sight, whose signals are transmitted quickly to the brain, the sense of smell is transmitted slowly to the brain. Is this statement true or false?
False
Do all the sense systems have similar modality in how they’re perceived?
Yes
A sensory system consists of what three things?
-sensory receptors
-neural pathways
-parts of the brain
A majority of the sensory systems are conveyed to the brain through what kind of nerves?
cranial nerves
What is hearing?
The conversion of vibrations and wavelengths in the air to something the brain can perceive
pinna
External surface of the ear that focuses wavelengths into our ear down the ear canal
tympanic membrane
Amplifies sound coming down into the ear canal
ossicles
-ear bones (stapes, incus, malleus)
-amplifies incoming sound through middle ear into inner ear
cochlea
senses and transmits information (sound) into the brain via CN 8
hair cells (ear)
-receptors that pick up changes of vibrations in the air and communicates changes to the brain
-hairs move against the tectorial membrane
cornea
protective outer coating of eye where light enters through
pupil
a hole created by the lens; light enters here
lens
changes shape using muscles in the eye to focus light in different areas
iris
-gives the eye its color
-focused by the lens
What cranial nerve is involved with hearing?
CN 8
What cranial nerve is involved with sight?
CN 2 (Optic Nerve)
What are the two photoreceptors?
rods and cones –> sends signal through neurons to the brain
rod
perceives brightness or dimness in light
cone
perceives color
ganglion cell
where neurons synapse to before being transmitted out of the eye and into the brain via the optic nerve
What cranial nerve is associated with touch in the head?
CN 5
What is taste?
picking up on chemical cues that have been dissolved by saliva in the mouth
What are the “five classes” of taste?
Salty
Sweet
Umami
Bitter
Sour
What tastes are considered positive?
Salty (small amounts)
Sweet (glucose)
Umami (protein)
What tastes are considered negative?
Salty (large amounts)
Bitter (toxins)
Sour (spoiled foods)
What cranial nerves are associated with taste?
CN 7, 9, or 10 depending on location
Where are the taste cells located?
Taste buds
Perigemmal
associated with spicy/sour
General Mucosal Innervation
outside of taste bud
associated with pain and temperature
What cranial nerve is associated with olfaction?
CN 1
How many “classes” of smell are there?
Thousands
Does olfaction have a slow or fast response time?
Fast response time since there is a direct connection between receptors and cranial nerve
Do olfactory receptors have specific ligands they bind to?
Yes
Main Olfactory Epithelium (MOE)
extensions from the olfactory bulb down into the upper part of the nasal cavity
where airborne odors bind to receptors and send signals to the brain
Do canines have whiskers?
Yes, on the muzzle
How are sensory systems studied?
-behavioral research
-electric stimulus
-anatomic research
Behavioral research (sensory systems)
-Two alternative forced choice (A vs B)
-Go/No-Go (to see if animal responds to stimulus)
Electric stimulus (sensory systems)
-Evoked potentials
-measuring electric stimulus that nerves send to the brain
Can be auditory, visual, olfactory, somatosensory
Anatomic research (sensory systems)
-Gross
-Microscopic
Does the breed of a dog impact how well they can sense something?
Yes, for instance:
-the shape and orientation of a dog’s ears vary depending on the breed (some breeds can hear better)
-the field of vision and eye diameter varies depending on the breed
Do dogs have a straight ear canal?
No, so you can clean them with q-tips
What is the approximate hearing range of dogs?
67-45,000 Hz
What is the frequency of dog whistles?
23,000-45,000 Hz
dichromatic
-the type of eyesight that dogs have
-equivalent to red-green color blindness in humans
crepuscular
can see best at dim/low-light areas (dawn and dusk)
scotopic
-HIGH sensitivity to light
-LOW sensitivity to color
-can detect brightness at about half the accuracy of humans
photopic
-HIGH sensitivity to color
-LOW sensitivity to light
tapetum lucidum
-a membrane of cells that is located behind the retina
-light bounces off this structure allowing the eye to take in more light
-allows to see in low-light areas
Describe the FOV of a dolicephalic dog.
Dolicephalic dogs have long snouts
They have a wider FOV, but a blind spot created by their long snout
Describe the FOV of a brachycephalic dog.
Brachycephalic dogs have smaller snouts (smushed noses)
They have a lower FOV, but no blind spots
Why is touch important for puppies?
They need to find their mom’s nipples to drink their milk
trigeminal nerve
innervation TO whiskers
facial nerve
innervation OF whiskers
Is taste important for dogs?
No, they rely more on olfaction for food detection (especially the 5 classes of taste)
How many taste buds does a dog have compared to a human?
Dogs have ~1700 taste buds while humans have ~10,000
Is there a difference between taste and flavor?
Yes, the experience of both can depend on an animal’s internal state - hunger, experience, genetics
-taste involves sweet, sour, bitter, salty, umami
-flavor involves olfaction , texture, chemesthesis (spicy/temperature)
What is the most developed sense system in dogs?
Olfaction
-seeking mates
-locating prey
-marking territory
vomeronasal organ (VNO)
-responds to pheromones
-connected to the amygdala or limbic system –> associated with emotion
-quick response time!
MRI
Magnetic Resonance Imaging
Looking at blood flow in the brain
Why is a dog’s sense of smell useful to humans?
Locating drugs, explosives, missing people
Sensing cancer, diabetes, etc.
Medical alert (addisons disease, seizures)
vestibular system
located in the inner ear
important for body position, movement, and balance
-as we move our heads, fluid in the semicircular canals move causing hair cells to move
nociceptive system
-has touch receptors throughout the body
-contains free nerve endings
-associated with pain and irritation (mechanical, thermal, chemical)
-usually in the skin and joints, but not as concentrated internally
What consists of the vestibular system?
semicircular canals and vestibule
semicircular canals
contains three canals at different angles
vestibular nerve
receives signals from hair cells of semicircular canal and vestibule
vestibule
has hair cells that sit below otoliths
otoliths
crystals that sit on top of hair cells; pulled by gravity to move hair cells
Almost all fats that dogs consume are digested in the ____.
A. large intestine
B. small intestine
C. stomach
D. cecum
B. small intestine
Dogs cannot digest proteins very well. True or false?
False
In regards to nutritional requirements, mark the correct statement below.
A. both dogs and cats can eat each other’s food
B. neither dogs nor cats should eat each other’s food
C. dogs can eat cat food, but cats cannot eat dog food
D. cats can eat dog food, but dogs cannot eat cat food
C. dogs can eat cat food, but cats cannot eat dog food
Why are dogs less likely to get heart attacks compared to humans?
A. they exercise more often than humans
B. they have a longer intestine
C. their low density and high density lipoprotein ratios are reversed compared to humans
D. they eat a more balanced diet
C. their low density and high density lipoprotein ratios are reversed compared to humans
What are canine teeth used for?
gripping
What are molars/pre-molars used for?
cutting
What does a dog’s diet consist of?
Mostly carnivorous, but can be omnivorous depending on availability
How is a dog’s digestion similar to other omnivores?
-digestion, absorption, and metabolism are similar
-nutrient and energy requirements relative to metabolic body weight are similar
Do dogs require arginine?
Yes, but not as much as cats
fat
-almost all is digested in small intestine
-bile acid emulsion
-gastric and pancreatic not lingual lipase
-blood transport is similar to other species
-dogs metabolize fats 2x the human rate
-dogs are adapted AEROBIC fat metabolism
-heart attacks are rare
carbohydrate
-central metabolic role for glucose
-no pre-gastric amylase
-pancreatic amylase
-disaccharidases
-monosaccharide transporters
What are the four types of carbohydrates?
-absorbable
-digestible
-fermentable
-non-fermentable
absorbable carbohydrates
monosaccharides
alcohols
digestible carbohydrates
disaccharides
starch
fermentable carbohydrates
polysaccharides
non-fermentable carbohydrates
polysaccharides
lignin
Do dogs require absorbable digestible carbohydrates?
Carbs are not necessary if there is enough protein in the diet.
For instance, if there is a low-protein diet with no carbs, then that leads to hypoglycemia and ketosis.
If there is a high-protein diet with no carbs, then that’s fine
Where are indigestible carbohydrates fermented?
In the colon; they are fermented into volatile fatty acids
volatile fatty acids (VFAs)
source of energy, but only ~5% since the colon is short
promotes sodium and water absorption
stimulates blood flow, cell turnover
prevents diversion colitis
What is the preferred fuel of colonocyte?
butyrate
What causes looser feces?
Low fat
High carbs
High VFAs
soluble fiber
What causes firmer feces?
High fat
Low carbs
Low VFAs
Vitamins and Minerals
most requirements of micronutrients are similar across species
salt requirements are low in dogs because they do not sweat, therefore, salt loss is low
Do dogs require vitamins?
They don’t need vitamin C, but they do need Vitamin D
What type of muscle fibers are in dogs?
Slow-twitch and fast-twitch
both high oxidative