1
Q
2 divisions of the nervous system
A
Central and Peripheral
2
Q
Central Nervous System includes..
A
brain and spinal cord
3
Q
Peripheral Nervous system includes..
A
peripheral nerves(cranial and spinal nerves)
4
Q
Describe spinal nerves
A
- Spinal nerves from the spinal cord are paired (sensory and motor nerves)
-The amount varies with the number of vertebrae in the vertebral column: - Rock Pigeon (Columba livia) has 39 pairs of spinal nerves; Ostrich (Struthio camelus) has 51
5
Q
How are spinal nerves attached to the spine?
A
- They have a ventral root containing motor neurons and a dorsal root containing sensory neurons
- it attaches to the Arachnoid Dura Pia
6
Q
Meninges
A
- protect the brain and spinal cord
7
Q
Describe the avian eye
A
- large relative to the size of the head and brain
- has anterior chamber (between iris and cornea) and posterior chamber ( between iris and lens)
8
Q
Nictitating membrane
A
- in many birds; has a cartilaginous-like connective tissue fold along the leading edge of the membrane called the marginal plait
- Sweeps the surface of the eye to keep it clean
9
Q
What 2 glands lubricate the surface of the eye
A
lacrimal gland and Harderian gland
10
Q
3 types of avian eyes
A
- flattened
- globose
- tubular
11
Q
flattened avian eye
A
- wide angle lens
12
Q
globose avian eye
A
- zoom lens
- in swallows, most raptors
13
Q
tubular avian eye
A
- adapted for low light levels
- in owls
14
Q
Name the layers of the eye
A
15
Q
Sclera
A
- layer that includes the sclerotic ring, cornea, Crampton’s muscle and Bruckner’s muscle
16
Q
Sclerotic ring
A
- made up of approx. 12-15 small bones called scleral ossicles
17
Q
cornea
A
- change their curvature to focus light on the light-sensitive cells of the retina
- this happens in the lens of the eye as well
18
Q
Crampton’s muscle
A
muscle increases the corneal curvature
striated muscle
helps focus on objects
19
Q
Bruckner’s muscle
A
- change the shape of the lens
- helps focuses on objects
- striated muscle
20
Q
Choroid
A
- layer 2 of the avian eye
- includes the iris, pupil, and lens
21
Q
iris
A
- thin layer of tissue that controls the size and shape of the pupil
- The underlying mechanisms that determine eye coloration follow the same general principles as feather coloration
- Iris color can differ among individuals within the same species, either between sexes or among the same species at different ages
22
Q
lens
A
- lens change their curvature to focus light on the light-sensitive cells of the retina
23
Q
The retina
A
- layer 3 of the avian eye
- includes the fovea, pecten, and optic nerve
24
Q
Optic nerve
A
- intertwined with blood vessel
- has a blind spot
- blind spot where optic nerve and retinal blood supply exit the eye orbit
- eyes on side have narrow sigh/wideron sides t while eyes of the front provide wider range of vision forward but with huge blind spot
25
pecten
- Source of nutrition and oxygen for the retina
- Allowed birds to increase the density of light receptors in the retina while entirely eliminating retinal vasculature
- This evolutionary innovation has greatly advanced the visual acuity of birds
26
Foveae
- concave depressions of high cone density
- has temporal and central fovea
27
temporal fovea
- forward-directed eyes with good binocular vision (fast-flying birds and aerial or diving predators
- owls
28
Central fovea
- located in the center of the retina near the optic nerve - images the portions of the visual field on either side of the bird
29
Tapetum lucidum
- A structural color produced by light scattering from an array of lipid spheres in the last layer of the retina (the retinal pigmented epithelium)
- in barred owls
30
binocular vs monocular vision
- Monocular vision refers to the ability to see with one eye, while binocular vision is the ability to see with both eyes
- monocular vision can give a wider range of sight but binocular vision can focus on objects better
31
