Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cell biology and physiology > Williams lectures > Flashcards

Williams lectures Flashcards

1
Q

Structure and properties of a sperm cell

A

LOOK AT A PICTURE

No transcription
no endoplasmic reticulum
no cytoplasm
relies on post transational modification: Glycolysation, phosphorylation

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

Sperms journey after ejaculation

A

Cervix - uterus - isthmus - oviduct (fertilisation) - oocyte

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

spermatogenesis definiton and how does it begin

A

Biological process of producing mature sperm cells occurs in the male gonad

  • starts at puberty caused by the release of gonadotropin releasing hormone from the hypothalamus
  • 74 days
  • Humands produce 1000 spermatozoa per heartbeat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Male reproductive organ structure

A

LOOK AT PICTURE

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

Temp of scrotum

A

35-36 - cooler than body

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

quality of sperm cells

A

95% abnormally formed
68% immotile
42% dead

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

3 phases of spermatogenesis

A

PROLIFERATION (MITOSIS)

DIVISION ( MEIOSIS)

DIFFERENTIATION (SPERMIOGENESIS)

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

Two products made in post pubertal testis

A

spermatozoa and hormones

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

Two compartments found in post pubertal testis

A
  1. Within seminiferous tubules
    Sertoli cells: nurture germ cells
    Developing germ cells
  2. Between tubules
    Leydig cells: androgen producing cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

sertoli cells

A

Germ cells grow inside sertoli cells. They form tight and adherens junctions to give nutrients them support

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

Blood testis barrier

A

Formed by tight junctions

  1. Separates developing germ cells from the immune system
  2. Control microenvironment for germ cells to develop properly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

role of sertoli cells in spermiation

A

They release mature sperm into the lumen of the seminiferous tube

Digest leftover cytoplasm from spermatids

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

What substances do sertoli cells secrete

A

Inhibin and andorgen binding protein to regulate spermatogensis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Seminiferous tubules

A

where spermatogensis occurs

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

Process of spermatogenisis

A
  1. prospermatagonia are activated by the endocrine signals they receive and undergo mitosis in the seminiferous tubule.
  2. Form spermatogonia (reservoir of self renewing stem cells) which all have same genetic material. Some of the type As spermatogonia form type A spermatogonia and start the process of spermatogenesis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Process of mitotic proliferation

A
  1. Type A spermatogonia undergo mitosis to form type B spermatogonia which divide again to form primary spermatocytes which will undergo meiosis
  2. All the primary spermatocytes are genetically identical to spermatogonia
  3. Primary spermatocytes move towards lumen and through and through the blood testis barrier
  4. Resting phase
  5. Chromosome duplicate ready for mitotic division (meiosis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Meiotic division of primary spermatocytes

A

Meiosis I: divide to form secondary spermatocytes
Meiosis II: Divide to form haploid spermatid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Sperm development

A

Spermatogonia - Spermatocytes - spermatids - Spermatozoa

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

Acrosome

A

Formed from the golgi apparatus which migrates to on end of nucleus and surrounds it.

Contains hydrolytic enzymes which are released upon binding to the zone pellucida of the egg to aid penetration.

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

Flagellum of sperm

A

Centrioles migrate to opposite end of nucleus to acrosome and form axoneme
Needed for sperm movement through the female tract

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

Mitochondria of sperm

A

Helically arranged around first part of flagellum
energy for motility

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

Nucleus of sperm cell

A

Sex determination (X Or Y)
Sperm DNA becomes highly condensed histones replaced with protamines - protect paternal genome during transport
Transcriptionally and translationally inactive

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

syncytium definition and function

A

Sperm cells remain connected by intercellular bridges until final stages of spermatogenesis due to incomplete cytokinesis.

Allows sharing of cytoplasmic component EG If you have a sperm that has a Y chromosome it can be supplied by essential proteins encoded by genes on the C chromosome

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

Cytoplasm of sperm cells

A

Forms residual body which is phagocytosed by sertoli cells and loss of organelles such as ER.

Sperm has very little cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Spermiation
last step of spermatogenesis intracellular bridges rupture Loss of spermatid cytoplasm Sperm released into lumen of seminiferous tubules in testis
25
What cells are involved with the endocrine control of testicular function
Sertoli cells and leydig cells
26
Role of Androgen (testosterone)
Development of testis Sexual function and characteristics ( puberty) Reproductive function Produced by leydig cells
27
Inhibin
Produced by sertoli cells Acts on pituatary gland Inhibits FSH production (sperm production)
28
Androgen binding protein
Product of sertoli cells binds and carries testosterone in testicular fluid of seminiferous tubules Maintain high levels of testosterone (100x more than in blood) Since testosterone is lipid solible it diffuses across plasma membrane binding to ABP prevents diffusion to increase concentration
29
Movement of sperm in to seminiferous tubules
Spermatozoa released from testis are immotile until they trasverse the epididymis (where sperm passes through) Moved by peristalisis (powerful periodic contractions)
30
Sperm length
10-15 um
31
How far do the sperm travel
30-40cm in female tract
32
How many sperm complete the journey to the oocyte
1 in a million
33
Processes that sperm undergo in the male and female tract
Male: sperm maturation Female: capacitation (allows them to penetrate and fertilize egg)
34
Epididymal organ regions
1. Caput (motility) 2. Corpus (Fertilising ability ) 3. Cauda (storage) 4. Vas deferens
35
epididymal maturation process
1. Removal of cytoplasmic droplet at epithelial cells of epidiymal (retention of cytoplasmic droplets is linked to reduced fertility) 2. Change in sperm proteome 3. Change in sperm surface - removal of external proteins sugars and lipid membrane 4. intracellular signalling pathways activate - phosphorylation
36
whats semen made up of
sperm and seminal plasma
37
How much semen i released during ejaculation
3ml - 100 million sperm
38
What glands is seminal plasma secreted by
accessory sex glands
39
The oocyte structure
Zona pellucida: protective jelly like layer Cytoplasm: contains food reserves for developing zygote chromosome: read to undergo second meiotic division after fertilisation covered in remains of follicle cells
40
oocyte journey in female tract (fertilisation)
1. Ovulation occurs 2. ovum released from ovary 3. fertilisation occurs (day 1) 4. zygote 5. cell division occurring 6. Blastocyst forms 7. Blastocyst reaches uterus 8. Blastocyst implants into uterine wall (day 5-7)
41
fertilisation process
1. many sperm attacking oocyte 2. One sperm breaks through the zona pellucida and enters the cell 3. Membrane depolarises which doesn't allow additional sperm to enter the cell 4. structure of the sperm cell mostly digested apart from nucleus 5. Fertilisation and development of the zygote
42
Requirement for fertility
1. Production of normal sperm and eggs 2. Sperm has to traverse female tract (egg and sperm have to be in the ampulla at the correct time - have about a day) 3. sperm penetrates and fertilises an egg 4. implantation of the embryo in the uterus 5. normal pregnancy
43
Differences and similarities between gametogensis in male and female
1. Oogenesis starts in embryo pre birth where as for males it starts at puberty and continues through life 2. oogenesis is not Continuous there are two phases where meiosis stops until hormone signals are recieved to carry one process 3. Each diploid cell in females develops into one halpoid cell in males 4 haploid cells form 4. Oogenesis continues after puberty and stops at menopause
44
Process of forming a zygote
Starts off as a primordial germ cell in the embryo They migrate to the genital ridge. They are then considered oogonium (diploid cells) During embryogenesis, they multiply to form primary oocytes which begin to enter meiosis I but arrested at prophase I During puberty (ovulation) they develop into secondary oocytes which are released at ovulation Start meiosis II but arrest at metaphase II If fertilization occurs they complete meiosis II the female and male pronucleus fuse pronuclear fusion forms zygote
45
Oogensesis
oogonia - (mitosis) - primary oocyte - (meiosis I arrests until puberty) - Puberty - resumes meiosis I - secondary oocyte and first polar body - (meiosis II during ovulation) - meiosis II arrest until fertilisation - ovum and second polar body
45
folliculargenesis
1. primordial follicle 2. primary follicle (contain oocytes) 3. secondary follicles surround by cells 4. secondary follicles grow and fluid is introduced into central follicle 5. forms graafian follicle 6. fluid builds up and ovulation will occur when the ovum opos out 7. leaves you with remains of the follicle - corpus luteum 8. corpus luteum matures into corpus albican
46
what somatic cells accompany the oocyte
granulosa cell: nurture germ cells, surround oocyte, produce oestradiol and progesterone theca cells: surround granulosa cells, produce horome androgen and progesterone, contribute to structure of the follicle
47
stages of folliculogenesis and there dependence
initial recruitment - gonadotropin cyclic recruitment - gondatropin dependent
48
Female germ cell number through years after contraception
After contraception proliferation of germ cell increases rapidly. At birth apoptosis begins (left with 2 million) at puberty it decreases again to about 400,000.
49
When does menopause occur
when there is a low ovarian reserve
50
How many of the oocytes will be ovulated in a life time
400-500
51
what is atresia ( oocytes)
degeneration - most oocytes undergo atresia
52
primordial follicle
primary occyte surrounded by a single layer of flattened granulosa cells
53
primary follicle
primary oocyte but granulose cells have become cuboidal and zona pellucida becomes visible
54
secondary follicles
primary oocyte granulosa cells proliferate and become 3-6 layers deep theca cells form two distinct layers 15-20 follicles recruited
55
tertiary follicle
secondary oocyte granulosa secrete follicular fluid occyte surrounded by corona radiata and stalk of cells (cumulis oophurus) only one per cycle
56
How do hormones during puberty control oogenesis
re initiation of oogenesis and folliculogenesis caused release of gonadotropin releasing hormone from hypothalamus (GnRH)
57
FSH
acts on ovary stimulates recruitment and development of follicles
58
LH
act on ovary stimulates follicle maturation ovulation and development of corpus luteum stimulate
59
role of corpus luteum
release progesterone to ready uterus for pregnancy
60
FSH + LH
stimulate secretion of oestradiol and ovulation
61
oestradiol production
LH stimulate theca cells to produce testosterone - FSH stimulates granulosa cells to make aromatase which converts the testosterone into oestradiol.
62
oestradiol
Growth of body and sex organ development of secondary sexual characteristics reproduction
63
progesterone
acts on uterus prepares uterus for pregnancy act on breasts stimulate development of mammary glands thickening of cervical mucus so no sperm can get through
64
Negative feedback ( oestrogen and progesterone)
Moderate levels of oestrogen and normal levels of progesterone supress FSH production by anterior pituitary
65
Positive feedback (oestrogen)
high levels of oestrogen at mid cycle stimulates release of GnRH which causes LH surge and FSH spike from anterior pituitary
66
Follicular phase
Secretion of GnRH secretes FSH and a little LH in response to FSH 15 follicles matured In response to LH testosterone produce and converted to oestrodiol oestrodiol supresses FSH production High levels of oestrodiol causes more release of GnRH causes FSH and LH surge
67
Luteal phase
Corpus luteum made - secrete progesteron and oestradiol No pregnancy, if no hCG from an embryo the corpus luteum degenerates - corpus albican progesterone and oestradiol levels fall removing negative feedback of FSH and cycle begins again arteries in endometrium constrict - mensturation
67
Characteristics of ovulation phase
high in follicular fluid and number of granulosa Follicle walls weaken ovulation of oocyte must be fertilised within 12-24 hours LH and FSH levels fall
68
What happens at week 6 to the corpus luteum
Placenta takes over its role and it degenerates into corpus albicans

Cell biology and physiology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions