Brainscape's Knowledge GenomeTM

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


See full index

RE > The Role of Sperm > Flashcards

The Role of Sperm Flashcards

1
Q

Pituitary Hormone Effects:

A

insert flowchart

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

Conc vs Motility vs Morphology

A

insert diagram

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

Spermatogenesis definition:

A
  • mitotic divisions of
    spermtogenia, the meiotic
    divisions of spermatogonia
    (diploid 2n DNA) to haploid
    spermatids (1n DNA) and the
    maturation to spermatozoa

*includes spermatocytogenesis
and spermiogenesis

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

Spermatocytogenesis

A
  • meiotic stages of
    spermatogenesis
  • spermatogonia (diploid 2n)
    develop into primary
    spermatocytes (diploid 4n), then
    into secondary spermatocytes
    (haploid 2n) and then into
    spermatids (haploid 1n)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Spermiogenesis:

A
  • maturation of spermatids
    (haploid 1n) to mature
    spermatozoa
  • no cell division involved
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Spermiation:

A
  • release of spermatozoa from
    Sertoli cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Sperm capacitation:

A
  • physiological changes
    spermatozoa must undergo in
    order to have the ability to
    penetrate and fertilize an egg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two main products of the testis?

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

Section of the Testis and Seminiferous Tubule:

A

insert diagram

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

Compartments of the Testis:

A
  • interstitial (inter-tubular)
    compartment
  • seminiferous tubule
    compartment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The epithelium of which compartment of the testis is sensitive to elevated temperature?

A

Seminferous epithelium

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

Testis: Compartments:

A

insert diagram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Testis: Interstitial Compartment:

A
  • highly vascularised
  • contains Leydig cells clustered
    around vessels
  • Leydig cells are responsive to LH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Leydig Cells:

A
  • vascularised stroma contains
    Leydig cells
  • function = synthesize
    testosterone, may be involved in
    testicular immune environment
  • 4-10mg testosterone daily
    secreted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Leydig Cells

A

insert diagram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Leydig Cells: Features:

A
  • abundant smooth endoplasmic
    reticulum (SER)
  • high mitochondria conc
  • both associated with steroid
    synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sertoli Cells:
- location
- cell type

  • function (2)
  • feature
  • function
A
  • located in germinal epithelium
  • somatic cells of testis
  • involved in testis formation and
    spermatogenesis
  • progression of germ cells to
    spermatozoa via direct contact
  • large cytoplasm an oval nucleus
    with dark nucleolus
  • Androgen Binding Protein is
    synthesised by sertoli cells where
    80% secreted into luminal fluid,
    20% into interstitial
    compartment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Sertoli Cells:

A

insert diagram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Sertoli cells are embryological equivalent to?

A

granulosa cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where does spermatogenesis take place?

A

Seminferous tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Anatomy of Seminferous Tubules:

A

insert diagram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Spermatogenesis:

A

insert diagram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What hormones are most important maintaining reproductive and sexual function?

A

androgens: testosterone and 5alpha-dihydrotestosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is testosterone is synthesised from?

A

acetate and cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Role of androgens:

A
  • expression of the male
    phenotype
  • male sexual differentiation
  • development, maintenance of
    secondary male characteristics
  • initiation and maintenance of
    spermatogenesis
26
Q

Testosterone Pathway to epididymis

A

Testosterone passes from the interstitial compartment to the seminferous tubules (lipid solubles)

Converted to dihydrotestosterone by 5 alpha-reductase in Sertoli cells

Androgen Binding Protein binds testosterone and transports it from the seminferous tubule to the epididymis

Taken up by a receptor-mediated processes into the principal cells of the initial segment and caput epididymis

27
Q

Pituitary Control of Androgens:

A
  • productions of androgens and
    spermatozoa related functionally
  • at puberty androgens rise and
    spermatogenesis commences
  • LH stimulates Leydig cells to
    produce androgens
  • FSH stimulates sertoli cells and is
    required for spermatogenesis
28
Q

Organisation of Seminiferous Tubules:

A
  • each cell 30-80cm long
  • 540m total length
  • peripheral myoid cells, then
    basement membrane, then
    sertoli cells and spermatogenic
    cells within the tubules
  • superficial to deep
  • the myoid cells are a muscle
    layer that surrounds the sertoli
    cells
29
Q

What prevents macromolecules and metabolites entering the fluid of the testis?

A

Physiological barrier formed by par and tight junction complexes between sertoli cells

creates a basal compartment and a separate adluminal compartment

this barrier is within the sertoli cell layer

30
Q

Junctions

A

insert diagram

31
Q

Where is the barrier in location to the spermatogonia?

A

smooth muscle surrounding tubule, one layer of germ cells, then barrier than next layer of germ cells and sertoli cells

32
Q

Mitotic proliferation occurs in which compartment of the seminferous tubule? (separated by junction barrier)

A

basal compartment

33
Q

What occurs in the adluminal compartment of the seminferous tubules?

A

meiosis and differentiation

34
Q

Three elements to spermatogenesis:

A
  • mitotic proliferation -> many
    cells
  • meiotic division -> genetic
    diversity
  • cell modelling -> package
    chromosomes for delivery to
    oocyte
35
Q

Spermatogenesis: Mitosis:

A
  • prospermatogonia = germ cells
    of immature testis
  • reactivated at puberty to
    undergo rounds of mitosis in the
    basal compartment of the tubule
  • Spermatogonia emerge
  • undergo a series of divisions to
    form a clone of cells
  • final round of divisions form a
    clone which divides to form
    resting primary spermatocytes
  • primary spermatocytes inhibit
    cavities formed in sertoli cell
    cytoplasm
  • nuclear division is completed,
    cytoplasmic division is not
  • primary spermatocytes are
    linked by cytoplasmic bridges
36
Q

Spermatogenesis:

A

insert diagram

37
Q

Spermatogenesis: Meiosis:

A
  • resting primary spermatocytes push
    through Sertoli cell junctions into
    adluminal compartment
  • enters meiotic prophase
  • paired homologous chromosomes
    form contacts at pachytene, break,
    swap segments and rejoin
  • first meiotic division = genetic
    diversity = two chromosome pairs
  • second meiotic division = two
    unpaired chromosomes in each cell
38
Q

What is most damaging for chromatid packaging?

A

ROS

39
Q

Spermatogenesis: Packaging:

A
  • cytoplasmic remodelling of spermatid
  • tail for forward propulsion
  • midpiece with mitochondria for
    energy = mitochondrial sheath
  • cap region forms for sperm oocyte
    fusion
  • acrosome forms to penetrate oocyte
40
Q

Sperm Diagram:

A

insert diagram

41
Q

How long does it take for an immature germ cell to develop into a mature male gamete?

A

16 days

42
Q

Where does spermatogenesis occur?

A
  • Testes
  • until sperm moves to the epididymis
    and gains motility
  • no resting phase during
    spermatogenesi
43
Q

Spermatogenic Cycle:

A
44
Q

What is the trigger that allows germ cells to differentiate into sperm cells?

A

Retinoic acid
Vitamin A

45
Q

What triggers the end of mitosis of spermatogonia and begin meiosis?

A

2nd pulse of Retinoic acid

46
Q

The final pulse of retinoic acid in spermatogenesis function?

A

spermiation

47
Q

Every 16 days a new generation of sperm cells are formed and hence in the testes —— are formed

A

layers
so some cells will be 0 days old, some will be 16 days, 32 days
but different “slices” will have different days eg day 5, 21, 37

newest generation is at the periphery of the tubule
hence superficial is new

48
Q

What is the spermatogenic cycle?

A

clock of retinoid acid pulsatile release every 16 days in humans

begins waves of germ cell differentiation

*time taken for reappearannce of the same stage within a given segment of the tubule

49
Q

Spermatogenic Wave

A

Distance between the same stage in testes

different patches of testes will begin differentiation on different days hence all patches will not have all layers

50
Q

The final stages of maturation of spermatozoa occurs where?

A
  • spermatozoa wash into the rete
  • through the vasa efferentia
  • into the epididymis where the fluid is
    absorbed and sperm is concetrated
  • in the rete they can twitch: by the
    causa epidiymis they can swim/move
  • process is dependent on androgen
    stimulation
51
Q

What % of seminal fluid is from the seminal vesicles?

A

85%
prostate gland secretes majority

52
Q

What does the seminal vesicles secrete?

A

Yellow, alkaline and viscous fluid that contains fructose, fibrinogen, prostaglandins, Vitamin C

53
Q

What does the endocervix do?

A
  • secretes mucous with cyclical
    variation
  • macromolecular network of mucin
    fibrils guiding spermatozoa
  • oestrogen stimulates watery mucous
  • progesterone inhibits secretory
    activity
  • sperm can penetrate from day 9,
    peaks at day 14
54
Q

What happens to 99% of sperm ejaculated in the vagina?

A
  • stuck in cervical mucous/expelled
    from the vagina entirely
55
Q

What does the endocervic offer sperm?

A
  • receptive at the time of ovulation
  • protection from hostile vagina, and
    from phagocytosis
  • supplementation of energy
    requirements
  • sperm selection by differential
    motility and morphology
  • short term reservoir within the
    endocervical crypts
  • initiation of the next stage in sperm
    maturation: capacitation
56
Q

3 properties of cervical mucous?

A
  • consistency: watery or viscous
  • spinnbarkeit: elasticity
  • Ferning: crystalisation on glass
    service
57
Q

What is capacitation?

A
  • sperm recovered at ejaculation do
    not fertilise ova immediately
  • *cholesterol must be lossed
  • phospholipids from the inner
    membrane
  • activation of phospholipases
  • hyperactivity motility
58
Q

Semen Analysis:

A
  • concentration
  • motility
  • morphology
  • volume: 1.5-6ml
59
Q

Asternozoospermia

A

low motility (slow sperm)

60
Q

Oligozoospermia

A

low concentration

61
Q

Azoospermia

A

no sperm

62
Q

Aspermia

A

no ejaculate

RE (52 decks)

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