1B - Development(1) Flashcards
Animals are described by?
-3 different axes
Axis 1: Rostral-Caudal
-Runs from front (head) of animal towards back (tail)
Axis 1 (another): Anterior-Posterior
- Anterior (direction animal moves while walking)
- Posterior (direction animal is moving AWAY from)
- Cat: Moves head forward (anterior) and moves away from the tail (posterior)
Axis 2: Lateral-Medial
- Starting from middle of animal’s body to outer parts of animals body
- Medial (towards midline)
- Lateral (away from midline)
Axis 3: Proximal-Distal
- Proximal (limb that is close to animal’s body)
- Distal (limb that is away from animal’s body
Humans are bi-pedal because we walk on our legs. What does this mean?
Humans move in the direction of the (anterior) ventral surface of the body
Animals, what are the directional terms?
- Front: Anterior or Rostral
- Back: Posterior or Caudal
Humans, what are the directional terms?
- Front: Anterior or Ventral
- Back: Posterior or Dorsal
There are 3 planes, name them
Sagittal, Frontal/Transverse, and Horizontal
Sagittal Plane
- Passes middle of animal’s body
- Divides left/right side
Mid-Sagittal
-Directly sliced on midline
Para-sagittal
-Parallel to sagittal plane
Frontal/Transverse
-Divides into front/back halves
Horizontal
-slide through dorsal and ventral
Vertebrates belong to what phylum?
Chordata
What non-veterbrate member is part of phylum?
Amphioxus (it is a chordate, but not a veterbrate)
How is amphioxus different than humans?
Does not have backbone (veterbrae)
Differences of Amphioxus to Veterbrates
1). No paired fins.
All veterbrates have paired fins. Amphioxus has small dorsal fin but no paired fins
2). Does not have jaw.
Almost all verterbrates have jaws which open/close and chew food.
Similarities of Amphioxus to Veterbrates
1) . Gill slits
- This is basic characteristic of all chordates. Most veterbrates have 5-6 gill slit.
2) . Stiffening Rod
- Run’s on back
3) . Notochord
- Gives chordates their name.
Where do gill slits develop?
Pharyngeal region
A basic characteristic of veterbrates, like humans, is to have gill slits. Do humans have gill slits?
Gill slits are present in the human embryo, but do not completely develop. Human external ear are remants of primordial gill slits
Where do cranial nerves form?
In correlation to radial branchial bars that lie in between gill slits
Notochord in Amphioxus?
Persists
Notochord in most veterbrates?
Squeezed out of existence by development of vertebral column.
