Earthworm dissection Flashcards
1
mouth
2
ganglia
3
dilator muscle
4
pharynx
5
aortic arches
6
esophagus
7
seminal receptacle
8
seminal vessicle
9
dorsal vessel
10
crop
11
guzzard
12
intestine
13
typhlosole
14
metanephridia
15
lateral nerve
16
nerve cord
17
ventral blood vessel
1
cuticle
2
circular muscle
3
longitudinal muscle
4
chaetae
5
metanephridium
6
dorsal blood vessel
7
typhosole
8
lumen of intestine
9
ventral blood vessel
10
ventral nerve cord
what phylum do earthworms belong to
Annelida
development of earthworms
protostome
type of symmetry of earthworms
bilateral
describe the body of an earthworm
made up of equal body segments, often with structures repeated IDENTICALLY one each segment
type of feeding
deposit feeding - soil and organic matter are ingested to extract nutrients
reproduction of earthworms (hermaphroditic or diecious)
hermaphroditic
what makes up the external anatomy
- chaetae
- mouth
- anus
- dorsal blood vessel
- clitellum
- genital pores
chaetae
small bristle-like hairs protruding from each segment
how many chaetae are there for each segment
8
opening to digestive tract
mouth
exit of digestive tract
anus
how is the dorsal blood vessel visible
through the semi-transparent skin as a dark line on the dorsal surface
clitellum
slightly swollen region that produces a mucous film that is important for reproduction
where can the clitellum be found
closer to the anterior end (head)
genital pores
pair of large pores which are the openings of the vas deferens
how do earthworms differ from polychaetes
there are NO visible external appendages or sense organs
what makes up the digestive system
- muscular pharynx
- esophagus
- crop
- gizzard
- intestine
- typholsole
most anterior portion of the alimentary tract
pharynx
why does the muscular pharynx look fuzzy
because of the dilator muscles extending along the body wall
how does the pharynx expand and suck in particles of soil
by the contraction of the dilator muscles
esophagus
food passes through for processing
crop
thin-walled sac for storage
gizzard
muscular organ for grinding food particles
intestine
chemical digestion and absorption
typholsole
rod of tissue hanging suspended in the intestine
function of typholsole
increased absorptive surface for absorbed food
parts of the circulatory system
- dorsal blood vessel
- ventral blood vessel
- aortic arches (hearts)
dorsal blood vessel
dark tube overlying the digestive tract
do worms have a closed or open circulator system
closed
ventral blood vessel
small, yellowish tube running along the underside of the intestine
how many hearts do earthworms have
5
aortic arches
pump the blood from the dorsal vessel into the ventral blood vessel
what picks up oxygen and discharges carbon dioxide
tiny capillaries in the skin of each segment
parts of the nervous system
- cerebral ganglia
- ventral nerve cord
- lateral nerves
cerebral ganglia
brain-like pair of concentrated nerves
what do the cerebral ganglia bear connections with
nerve cord beneath
ventral nerve cord
thin, whitish cord located below the ventral blood vessel
lateral nerves
run into the muscles of the body wall from swollen regions on the ventral nerve cord
parts of the reproductive system
- seminal vesicles
- seminal receptacles
seminal vesicles
3 large whitish sacs where sperm is RELEASED from very tiny testes
where does sperm travel to once released from testes
the seminal vesicles where they mature
seminal receptacles
2 pairs of small, round sacs that received sperm from ANOTHER PARTNER during copulation
parts of the excretory system
metanephridia
metanephridia are located
one per segment in region POSTERIOR to gizzard
metanephridia
excretory organs where coelomic fluid enters the open end of each tubule, metabolic waste is removed via a pore through the body wall
cuticle
external layer protecting the skin
epidermis
cellular layer of tissue beneath the cuticle
what functions in DIRECT gas exchange with the environment and prevention of desiccation
cuticle
circular muscles
thin layer of muscular tissue which contracts = squeezes the worm long and thin
longitudinal muscles
thick layer of muscles beneath the circular muscles - when contracted = squeeze worm short and fat
what muscles squeezes the worm short and fat
longitudinal muscles
what muscles squeezes the worm long and flat
circular muscles
where are intestines located
centrally in coelom
cuticle and epidermis function
protection
circular and longitudinal function
locomotion
pharynx function
swallow food
gizzard function
break down food
repetitive body segments function
help the worm move
metanephridia function
remove metabolic waste
chaetae function
- anchorage
- locomotion
seminal vesicle function
sperm production
seminal receptacles
sperm storage
what are these structures
chaetae
1
pharynx
2
heart
3
seminal vesicles
4
septa
5
dorsal blood vessel
6
intestine
7
gizzard
8
crop
9
seminal receptacle