Nervous System Flashcards
What is the connective tissue that surrounds each myelinated nerve fiber?
endoneurium
What is the sheath of connective tissue surrounding a bundle of nerve fibers?
perineurium
What is the outermost dense irregular connective tissue surrounding a peripheral nerve and fills the spaces between the nerve fasciles?
Epineurium
Oligodendrocytes form what?
myelin sheath
What communicating rami supplies the epaxial muscle?
dorsal ramus
What communicating rami supplies the hypaxial muscles?
ventral ramus
In agnathans, the dorsal and ventral roots do not unite. T/F?
T
In higher vertebrates like amniotes, the dorsal root fibers contain what kind of neurons?
sensory neurons
In humans, ventral root fivers contain what kind of neurons?
motor neurons
What are the primary vesicles of the brain?
- forebrain (prosencephalon)
- midbrain (mesencephalon)
- hindbrain (rhomencephalon)
The telencephalon forms what part of the brain?
cerebral hemispheres
The diencephalon gives rise to what structures of the brain?
Epithalamus, Thalamus, Hypothalamus
The mesencephalon forms what part of the brain?
tectum and tegmentum
The metencephalon forms what part of the brain?
adult cerebellum
The myelencephalon forms what part of the brain?
adult medulla
Metencephalon arises from what primary vesicle?
rhombencephalon
The telencephalon and diencephalon arises from what primary vesicle?
prosencephalon
What are the expansions/spaces within the vesicles called?
ventricles
Where is the 3rd ventricle found?
diencephalon
What is the neural canal in mammals called?
cerebral aqueduct
where is the 4th ventricle located at?
metencephalon and myelencephalon
What produces the cerebrospinal fluid in the central canal of the brain?
choroid plexus
What are the three flexures ONLY found in birds and mammals?
- cephalic flexure (@mesencephalon)
- pontine flexure (@metencephalon)
- cervical flexure (@myelencephalon)
What are the types of receptors based on location?
Interoreceptors & Exteroreceptors
What is an example of electromagnetic stimuli?
heat & light
What is an example of a chemical stimuli?
taste & smell
touch and sound are examples of what kind of stimuli?
mechanical
Sensations are received by naked nerve endings. T/F?
T
Where are sense capsules located at?
epithelial and connective tissues of tetrapods
What kind of receptors are general somatic
receptors that acquaint vertebrates of relative
positions of parts of the body?
proprioceptors
Proprioceptors respond to what that makes it contribute to postural reflexes?
tension
What are otoliths?
hard objects within the internal ear of some vertebrates. It acts as depth registers for several teleosts
The magnetic sense has been found in some fishes, amphibians, sea turtles, birds, rodents, bats, and cetaceans. Where is it located?
ethmoid region of the head
What is the most primitive sense for vertebrates?
olfaction
Taste is made possible by what?
chemoreceptors and olfactory organs
Where do taste organs originate from?
endoderm
What are the receptor cells or gustatory receptors?
taste buds
What are neuromasts for?
detecting vibrations and movement in water (lateral, especially for fishes)
Melatonin is an antigonadotrophin. What does this mean?
inhibits the release of sex hormones from the gonads. basically prevent unwanted pregnancies
What does the pineal gland secrete?
melatonin
Where does melatonin bind?
suprachiasmatic nucleus at the optic chiasma of the brain
Several nerve cells with their axons can be
grouped into nerve fibers called __________
which is surrounded by perineurium
fasciculus
What are the types of neurons based on the protoplasmic process?
- unipolar
- bipolar
- multipolar
What are astrocytes?
Star shaped neurons that connect neurons with capillaries.
What neuron mainly does phagocytosis to dispose dead cells, debris, and pathogens in the CSF?
microglia
What neuron lines the fluid like cavities of the CNS for protection?
ependymal
Where does the dorsal and ventral nerves for fishes and amphibians join?
outside the ventral column
In fishes and amphibians, where does the dorsal ramus originate from?
epaxial origins
In fishes and amphibians, where does the visceral ramus originate from?
hypomere
In fishes and amphibians, where does the ventral ramus originate from?
hypaxial origins
How many cranial nerves do agnathans, most fish, and living amphibians have?
10
Which category of cranial nerves join the brainstem at a lateral level?
1st Category: 0, 5, 7, 9, 10, 11
What category serves as structures that are centered on the head? Enumerate.
3rd Category: 1, 2, 7, 8, 9, 10
What is the function of a dorsal root?
sensory
What is the function of a ventral root?
motor
Which of the two roots, ventral or dorsal, has no ganglion?
ventral (motor)
What does the dorsal ramus supply?
epaxial muscles + skin at the dorsal part of the body
What does the ventral ramus supply?
hypaxial muscles + skin of the sides + ventral part of the body
What is the main difference between the cranial nerves among early craniates and amniotes?
Early craniates: D & V roots DO NOT Unite, D roots are mixed, D root ganglia may be absent
Amniotes: D & V roots DO unite, D roots are mostly sensory, D root ganglion cell bodies are more unipolar
What part of the brain modifies and monitors motor output? (hint: involuntary)
cerebellum
What parts of the brain make up the metencephalon?
pons & cerebellum
What parts of the brain make up the myelencephalon?
medulla oblongata
What part of the brain contains centers important in regulating respiration, heartbeat, and intestinal motility?
myelencephalon
What portion of the pons contain the descending fibers passing from the other parts of the brainstem?
basilar portion
The pontine tegmentum of the pons contain the ascending fibers that lead to where?
thalamus
What parts of the brain make up the mesencephalon?
tectum (roof of midbrain) & tegmentum (floor of midbrain)
The tectum is split into the optic lobes (inferior colliculi) and auditory lobes (Sensory colliculi). These 4 colliculi form what?
corpora quadrigemina
The epithalamus, hypothalamus, and thalamus are part of what region of the brain?
diencephalon
The hypothalamus is responsible for what?
homeostasis, reproductive behavior, alertness
Which gland does the hypothalamus stimulate to produce many of its functions?
pituitary gland
What does the telencephalon consist of?
cerebrum
Which part of the brain performs the highest functions? This includes consciousness, thinking, etc.
cerebrum
What are the 2 regions of the cerebrum?
pallium (dorsal) & subpallium (ventral)
Which part of the cerebrum does the septum and striatum (basal ganglia) belong to?
Subpallium
The septum is an important part of the __________ system.
limbic
What is the function of the striatum (basal ganglia)?
controls sequence of actions in complex movements
What is the difference between the choroid plexus and arachnoid villi?
choroid plexus = secretes CSF; arachnoid villi = absorption and passageway of CSF
What is the specialized system of capillary endothelial cells that protects the brain from harmful substances in the bloodstream while supplying the brain with the required nutrients for proper function?
blood brain barrier
What is the flat, undifferentiated, contractile connective tissue cells, which develop around capillary walls.
pericytes
What provides mechanical support for cell attachment, serves as a substratum for cell migration, separates adjacent tissue, and can act as a barrier to the passage of macromolecules? (between brain capillaries, astrocytes, and pericytes)
Basal lamina
What are the factors affect the ability of a substance to cross the BBB?
- barrier related factors
- peripheral factors
