Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Embryology Exam I > Gamete Transport And Fertilization > Flashcards

Gamete Transport And Fertilization Flashcards

1
Q

How is the ovulated egg transported?

A

-contractions of the tubal smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Outline of the transport time of the egg through the uterine tube.

A
  • departure time: day 0
  • slow transport in ampulla: 72hrs
  • rapid transport through isthmus: 8hrs (requires progesterone)
  • uterine arrival time: 3-4 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is sperm transported after spermiogenesis?

A

-passive transport via testicular fluid, smooth muscle contractions, and cilia from seminiferous tubules
+through rate testis
+through efferent ductules
+to head of epididymis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When and where do sperm fully mature in the male?

A

-maturation in the head of the epididymis (12 days)
+changes in glycoproteins in plasma membrane of sperm head
-sperm are capable of fertilization by the time they reach the tail of the epididymis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the path of ejaculation?

A

-ductus deferens
-addition of fluid secretions
+seminal vesicles
+prostate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do the seminal vesicles add to the sperm?

A

-fructose and prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the prostate add to the sperm?

A

-citric acid, Zn, Mg, phosphatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some obstacles the sperm will encounter in the female reproductive tract?

A

-upper vagina
+seminal fluid buffers acidity of vaginal fluids (pH: 4.2-7.2)
-cervix
+pH: 6-6.5 -> optimal for sperm motility
-cervical canal
+mucus block -> composition and viscosity of mucus changes during mid-cycle from thick to thin and watery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outline the path sperm takes in the female reproductive tract.

A

-initial rapid transport
+some spermatozoa reach uterine tubes within 5-20mins after ejaculation
+relies mostly on muscular movements of female tract
+these sperm are NOT capable of fertilizing an egg
-slow transport
+swims through cervical mucus (2-3mm/HR)
+storage in cervical crypts
+may not reach oviducts for 2-4 days
-isthmus
+capacitation
+after release following capacitation, sperm move up oviduct (swimming and peristaltic contractions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does fertilization typically occur?

A

-ampulla of uterine tubes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is capacitation? And what does it involve?

A

-required for sperm to undergo acrosomal reaction
-occurs inside the uterine tube in isthmus
-requires binding of sperm to tubal epithelium
-followed by a period of hyperactivity and release of sperm in small numbers
-involves:
+removal of cholesterol from sperm surface (inhibits premature capacitation)
+removal of glycoproteins (from epididymis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the steps in fertilization?

A
  1. Penetration of corona radiata
  2. Attachment to zona pellucida
  3. Acrosomal reaction and penetration of ZP
  4. Binding and fusion of sperm and egg
  5. Prevention of polyspermy
  6. Metabolic activation of the egg
  7. Decondensation of the sperm nucleus
  8. Completion of egg meiosis
  9. Development and fusion of male and female pronuclei
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is involved in the penetration of the corona radiata?

A
  • fusion of the outer acrosomal membrane with the sperm plasma membrane creating portals through which the contents of the acrosome can be released
  • fragmentation of sperm membrane to release acrosomal enzymes
  • swimming movements also help in the penetration through the corona radiata
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is one of the major enzymes in the acromegaly and what does it do?

A

-hyaluronidase

+helps to breakdown the hyaluronic acid component of the intracellular matrix between the corona radiata cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the steps in the acrosomal reaction?

A
  • ZP3 is one of four glycoproteins in ZP
  • attachment of sperm to ZP is mediated by ZP3 -> stimulates acrosomal reaction in mammals (acts thought G proteins in the sperm plasma membrane)
  • massive influx of Ca+2 through sperm plasma membrane
  • exchange of Na (influx) and H (effluent) increase pH
  • followed by penetration of sperm through ZP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is acrosin? Where is it found in the sperm? What does it do?

A
  • a serine proteinase involved in the penetration of the ZP
  • originally referred to as zona lysin
  • NOT released from the acrosome, but attached to the main portion of the acrosomal membrane that fuses to the remaining sperm plasmalemma adn overlies the nucleus
  • acrosin digests a small hole through the ZP and assists in the the penetration of swimming sperm through the ZP
17
Q

How many blocks are there?

A

2 types

18
Q

What is the fast polyspermy block?

A
  • consists of rapid depolarization of egg plasmalemma
  • goes from -70 to 10mV in 2-3 secs
  • temporarily prevents polyspermy and allows time for the egg to establish the slow block
19
Q

What is the slow block to polyspermy?

A

-characterized by release of polysaccharides from the cortical granules located under the plasmalemma of the egg
+polysaccharides enter perivitelline space and become hydrated, producing a swelling that increases width of perivitelline space

20
Q

What are the three final steps in fertilization?

A
  • metabolic activation of egg
  • decondensation of sperm nucleus
  • completion of meiosis in oocyte
21
Q

What happens during metabolic activation of the egg?

A

-initiated by release of Ca+2 within egg cytoplasm in response to introduction of phospholipase C zeta by sperm-released calcium
+initiates blocks to polyspermy
+stimulates increase in egg respiration and metabolism via the Na-H exchange mechanism
+results in an increase in pH and an increase in oxidative metabolism

22
Q

What occurs during the decondensation of the sperm?

A
  • sperm nuclear membrane becomes more permeable and allows entry of egg cytoplasmic factors which reduce disulfide cross-linkage to sulfhydyl groups
  • tightly packed sperm chromatin becomes more loosely packed and male pro nucleus is established
23
Q

What are pronuclei?

A

-nuclear material of the head of the sperm and egg after the egg has been penetrated by the sperm

24
Q

What is a zygote?

A

-single called stage at which the male and female pronuclei have fused together and share a common membrane, establishing a diploid chromosome number

25
Q

What does the sweeping of the fimbriae on the uterine tube do?

A
  • increase in ciliate on of tube epithelial cells

- increase in activity of tubal smooth muscle cells

Embryology Exam I (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions