Lecture 19 - Nervous system of the head Flashcards
What type of brain/head does a chordate have?
No skull or brain
What type of brain/head does a primitive vertebrate have?
Skull and tripartite brain
What type of respiratory system does a chordate have?
Non-muscular pharynx and water moved by cilia
What type of respiratory system does a primitive vertebrate have?
Muscular pharynx and water moved by muscles
What type of digestive system does a chordate have?
Ciliated gut action and intracellular digestion
What type of digestive system does a primitive vertebrate have?
Peristaltic muscular gut
Extracellular digestion
What type of circulation system does a chordate have?
Contracting vessels
What type of circulation system does a primitive vertebrate have?
Pumping heart, blood transport, gases and RBC’s
What type of osmoregulatory system does a chordate have?
Passive coelomic feeding
What type of osmoregulatory system does a primitive vertebrate have?
Glomerular kidney
What type of locomotion does a chordate have?
Notochord main support / simple myomeres
What type of locomotion does a primitive vertebrate have?
Vertebral main support, complex (W) myomeres
What are the things that developed that separated craniatas from the rest of the craniatas?
Pharyngeal system, cranium, paired sensory organs, neural crest, and tripartite brain
What is the fundamental vertebrate adaptation?
HEAD
What does a head require?
A neural crest
What are the three layers of the epiblast?
Endoderm - Mesoderm - Ectoderm
What is the “head” derived from?
Ectoderm
What all derives from the ectoderm?
CNS, PNS, epidermis, and CT of the head
What day does neurulation begin?
day 17
Where is the notochord located?
Mesoderm
What does the notochord induce?
Ectoderm to form neural plate
What does the neural plate become?
Neural groove – Neural tube
What does the neural tube form?
CNS
Where does the neural crest rise from?
Ectoderm near the neural tube
What does the neural crest form?
PNS and other structures
What three embryonic structures are unique to vertebrates?
Neural crest, neurogenic placodes, and muscularized hypomere
What is the hypomere?
Part of the myotome that forms muscles of the body wall and is innervated by a branch of the spinal nerve
Where do some sensory neurons derive from?
Neural crest
What so the sensory neuron from the neural crest do?
Provide critical information of muscle contraction and wide range of crest-derived exteroreceptors
What do the sensory receptors of the neural crest sense?
Temperature and tactile stimuli
What are the sense organs developed from?
Neurogenic/ectodermal placodes
What do the ectodermal placodes + neural crest form?
Sensory ganglia for CN’s V, VII, IX, and X
What is the pattern of head innervation based on?
gill arches
Where are two places in the brain that the CN’s come from?
Cortex/cerebrum
– and –
Brainstem
How many cranial nerves are there?
12
What is CN I?
Olfactory
What is CN II?
Optic
What is CN III?
Oculomotor
What is CN IV?
Trochlear
What is CN V?
Trigeminal
What is CN VI?
Abducent
What is CN VII?
Facial
What is CN VIII?
Vestibulocochlear
What is CN IX?
Glossopharyngeal
What is CN X?
Vagus
What is CN XI?
Accessory
What is CN XII?
Hypoglossal
What CN’s carry PNS?
III, VII, IX, and X
What does CN III do alone?
Constrict the pupil
What does CN VII do alone?
Innervate secretory cells for saliva, tear, and mucus production
What does CN IX do alone?
Innervate secretory for saliva production
What does CN X do alone?
Innervation of thoracic and abdominal organs
What does CN III, VII, and IX innervate together?
Specially named parasympathetic ganglia
What CN’s partake in SNS of the head?
None, the body innervates the head
What does the SNS do in the head?
Dilate the pupils and constrict arteries
