exoskeletons that must be shed for growth
ecdysozoans secrete ____
cuticle – that sheds periodically
nematodes are covered with a proteinaceous ____
parasite found in the intestines of animals – food contamination
ascaris is found:
1) determine sex
2) use stereoscopic microscope to look at ends of the worm
3) open animal by mid dorsal incision along the length of the body with a probe or scissors
4) pin down body wall
5) observe prepared slide of cross section body of a female
2) use stereoscopic microscope to look at ends of the worm
3) open animal by mid dorsal incision along the length of the body with a probe or scissors
4) pin down body wall
5) observe prepared slide of cross section body of a female
Ascaris Lab Procedure
females are larger and male’s posterior end is sharply curved
determining sex of ascaris
mouth: anterior end – 3 lips border this opening
anus: (slitlike) located ventrally near the posterior end
anus: (slitlike) located ventrally near the posterior end
location of mouth and anus:
not true coelom
body cavity:
masses of coiled tubules of varying diameters fill body cavity
reproductive organs:
flattened, extending from mouth to anus – tube within a tube (outer tube is the body wall)
digestive tract:
two pale lines running laterally along the length of body in body wall
lateral lines:
consists of two longitudinal tubes lying in two lateral lines
excretory system:
requires no oxygen
so *no organs for gas exchange or circulation*
so *no organs for gas exchange or circulation*
anaerobic
In through the mouth and absorbed by the intestinal tract
How would nourishment be taken into the body of Ascaris and circulated?
consists of a ring of nervous tissue around the anterior end of the worm, one with dorsal and one ventral nerve cord
nervous system:
No
Are there signs of segmentation in the body wall or in the digestive, reproductive, or excretory systems?
Mesenteries – a fold of the peritoneum (membrane) that attaches the stomach, small intestine, pancreas, spleen, and other organs to the posterior wall of the abdomen
Support system of Ascaris:
cuticle (noncellular)
epidermis (cellular)
muscular fibers
muscle from mesoderm lies at the outer boundary of the body cavity
intestine (endoderm)
epidermis (cellular)
muscular fibers
muscle from mesoderm lies at the outer boundary of the body cavity
intestine (endoderm)
body wall made up of (outside inward):
yes, a mesodermal tissue
Can you detect muscle tissue adjacent to the endodermal layer?
Triploblasts
What is a coelom with an outer lining of mesoderm and an inner lining of endoderm?
There are two uteri that open into the female reproductive organs & sections of coiled oviducts with small lumens and some ovaries with no lumen (inside space of a cellular component or structure)
What’s inside the uteri of Ascaris when observed in cross section under the microscope?
-Long thin body that can fit through intestinal tracts
-need to host their eggs in victims to ensure their life cycle
-need to host their eggs in victims to ensure their life cycle
List some features of Ascaris that are possible adaptations to parasitic life:
