Chapter 7 II

Question 1

3 sections of the brain

Answer 1

• forebrain, midbrain, and hindbrain

Question 2

forebrain

Answer 2

• Complex behavioral instincts and instructions, sensory integration, and learned intelligence
• includes the olfactory bulbs and cerebral hemispheres

Question 3

midbrain

Answer 3

• Regulates vision, muscular coordination and balance, physiological controls, and the secretion of neurohormones that control seasonal reproduction
• Includes the optic lobes and chiasmata and the cerebellum

Question 4

hindbrain

Answer 4

• Links the spinal cord and peripheral nervous system to the major control centers of the brain
• Cranial nerves, except those controlling vision and smell, enter the brain through the medulla

Question 5

How many cranial nerves does a bird have?

Answer 5

12!

Question 6

Olfactory nerve

Answer 6

• cranial nerve
• entirely sensory - cell bodies lie within the olfactory epithelium of the nasal cavity

Question 7

optic nerve

Answer 7

• cranial nerve
• sensory- larger than any other cranial nerve

Question 8

oculomotor nerve

Answer 8

• cranial nerve
• innervates the eye muscles, eyelid muscles and the gland of the third eyelid

Question 9

trochlear nerve

Answer 9

• cranial nerve
• a small nerve that innervates the dorsal oblique eye muscle

Question 10

trigeminal nerve

Answer 10

• cranial nerve
• the second largest cranial nerve, has both sensory and motor components
• 3 divisions: the ophthalmic, maxillary, and mandibular nerves

Question 11

opthalmic nerve

Answer 11

• division of cranial nerve trigeminal nerve
• sensory from the nasal cavity, eyeball, upper eyelid, forehead, and upper bill. It is very important in ducks and geese, as this nerve innervates the bill tip organ

Question 12

maxillary nerve

Answer 12

• cranial nerve division of trigeminal nerve
• is sensory from the skin of the face, upper jaw, upper eyelid, and conjunctiva

Question 13

mandibular nerve

Answer 13

• cranial nerve division of trigeminal nerve
• sensory to the lower beak and rictus, and conveys motor impulses to the muscles used in mastication

Question 14

abducent nerve

Answer 14

• cranial nerve
• supplies motor impulses to the lateral rectus muscle of the eyeball and to the quadratus and pyramidalis, the two skeletal muscles that pull the third eyelid across the eyeball to clean its surface

Question 15

facial nerve

Answer 15

• cranial nerve
• supplies motor impulses to the hyoid muscles for tongue protrusion, to the depressor muscle that lowers the mandible, to constrictors of the neck, and to the muscle that tenses the columella ear ossicle

Question 16

vestibulocochlear nerve

Answer 16

• cranial nerve
• sensory nerve for hearing and balance

Question 17

glossopharyngeal nerve

Answer 17

• cranial nerve
• supplies sensory and motor impulses to the tongue, pharynx, esophagus, and throat both directly and through anastomoses with the vagus, spinal accessory, and hypoglossal nerves

Question 18

vagus nerve

Answer 18

• cranial nerve
• the major visceral sensory and visceral motor nerve to the thoracic and abdominal organs

Question 19

accessory nerve

Answer 19

• cranial nerve
• arises from the first two cervical segments of the spinal cord, ascends through the foramen magnum, and exits from the skull with the vagus. It is distributed in the head region with the vagus

Question 20

hypoglossal nerve

Answer 20

• cranial nerve
• supplies the tongue, larynx, tracheal muscles, and syringeal muscles

Question 21

Describe the relation of brain mass and body mass in birds

Answer 21

• typically as body mass increases brain mass will increase as well
• parrots, owls, crows, woodpeckers, and hornbills tend to have a higher growth of brain mass relative to body mass
• however, avian species with similar body mass can have strongly various brain sizes

Question 22

Compare birds to other vertebrates for the relationship of brain mass to body mass

Answer 22

• avian brain sizes overlap extensively with mammals
• reptiles are on the lower end of this data set
• as one increases, the other increases

Question 23

Pallium

Answer 23

• the layers of grey(neurons) and white matter(axons) - the cortex - that cover the upper surface of the cerebrum in vertebrates

Question 24

Subpallium

Answer 24

• the non-pallial part of the telencephalon (the basal nuclei(nervous system) or ganglia(peripheral system), a cluster of neurons)

Question 25

Striatum

Answer 25

- part of subpallium

Question 26

Mammal brains vs bird brains

Answer 26

- mammal cerebral cortex functions in more complex cognitive processes - the mammalian striatum is involved in instinctive and reflexive behavior - the telencephalon in mammals has a large complex pallium and relatively small subpallium, while birds have a small pallium and a large subpallium

Question 27

How did this observed difference lead to a misinterpretation of the function of avian brains? How are avian brains now understood?

Answer 27

- swapped sizes of brain parts could lead to misinterpretation of birds being less intelligent - however, we now know The avian forebrain is composed of complex pallial neural cell types with circuits, gene expression, and neurotransmitter composition like the mammalian cortex - Comparisons of the size, mass, and the number of neurons in forebrain (red), midbrain (blue), and hindbrain (yellow) of a jay, a raven, and a macaw to three species of primates - These intelligent bird species have more pallial neurons in their forebrains (red) than do primates with brains that are over three times more massive