Spermatogenesis Flashcards

(61 cards)

1
Q

Where are sperm produced?

A

testes

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2
Q

Where does sperm get stored?

A

epididymis

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3
Q

What happens in ejaculation?

A

sperm moves out epididymis via vas deferens to enter prostatic urethra as ejaculatory duct

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4
Q

What is the ejaculatory duct?

A

area where vas deferens combine with seminal vesicle outflow

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5
Q

Where’s testosterone produced?

A

testes

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6
Q

Why do testes lie in a scrotum outside the body?

A

Optimum temperature for sperm production - 1.5 - 2.5 degree below body temperature

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7
Q

How spongy tissue in penis assists in ejaculation?

A

spongy, very vascular, engorges with blood to produce erection
suppresses urethra so urine can not flow well when there is an erection

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8
Q

Orchidometer

A

measure testes size

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9
Q

site of spermatogenesis?

A

seminiferous tubules

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10
Q

What is the rete testis?

A

An area where all the seminiferous tubules come together

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11
Q

What happens in the rete testis?

A

All the sperm concentrate in this area

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12
Q

Journey of a sperm

A
  1. Produced in seminiferous tubes in lobules
  2. Concentrated in rete testis
  3. Stored in epididymis from rete testis
  4. Leads to vas deferens
  5. Which links to prostate urethra
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13
Q

What are the walls of the seminiferous tubules made up of?

A

Sertoli cells

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14
Q

Describe the type of cell sertoli cells are

A

Tall, columnar endothelial cells

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15
Q

Female equivalent of sertoli cells?

A

granulosa cells

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16
Q

What’s on basement membrane, between sertoli cells?

A

Spermatogonia

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17
Q

What’s between the seminiferous tubules?

A
  1. Ledwig cells
  2. Interstitial fluid
  3. Blood and lymphatic vessels
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18
Q

Difference between cells closer to tubule + cells further away

A

Closer = more mature
Further = less mature.
Cells become more mature as they travel closer to tubules

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19
Q

Which cells undergo mitosis and why?

A

Spermatogonium (primordial germ cells) undergo mitosis to increase the number of spermatogonium

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20
Q

B-Spermatogonium

A

Differentiating progenitors which commit to meiosis - forming primary spermatocytes.

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21
Q

Where’s B-Spermatogonium?

A

Move towards seminiferous lumen, between sertoli cells.

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22
Q

Leydig cells

A

produce testosterone

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23
Q

Female equivalent of Leydig cells?

A

theca cells

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24
Q

How do the sertoli cells divide tubules?

A
  1. Interstitial space
  2. Luminal compartment - run through middle of cells
  3. Adluminal compartment - seperated by sertoli cells
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25
Adluminal compartment
sertoli cells form tight junctions between each other keeping developing sperm in confined compartments in the walls of tubules
26
Why are tubules divided into different compartments?
keeps spermatogonia in specialised environment to pick up nourishment + secretions from sertoli cells
27
Blood-testis barrier
sertoli cells form between interstitial space + inside of tubule preventing immune system from invading or looking into testis
28
Why immune-related issues in vasectomy?
testis content can leak into circulation - immune bodies see sperm + produces antibodies against individual's own sperm
29
A spermatogonia
germ cells - divides mitotically to replenish themselves forever
30
B spermatogonia
commit themselves to meiosis to produce spermatozoa
31
What are the changes that sperm undergo as they move towards the lumen?
1. Meiosis occurs 2. Become haploid 3. Undergo morphological changes
32
Female gamete production
1. Oogonia all laid down in foetus 2. Oogonia undergo meiosis to become oocytes 3. Oogonia can't produce more oocytes by mitosis 4. Limited supply of oocytes
33
Male gamete production
1. Spermatogonia laid down in foetus 2. Spermatogonia may either undergo meiosis to become spermatocytes OR undergo mitosis to replenish their supplies 3. Limited supply of oocytes whilst lifetime supply of spermatogonia
34
stages of spermatogenesis
1. Mitotic proliferation of spermatogonia 2. Meiosis + development of spermatocytes (cell) 3. Spermiogenesis - morphological changes of cell
35
What are the different types of spermatogonia?
3 different types: 1. Ad - A dark 2. Ap - A pale 3. B
36
Morphological changes of maturing sperm?
1. Elongation (tail) 2. Loss of cytoplasm 3. Movement of cellular content
37
Difference between HPG-Axis in males and females?
Females - cyclical - runs on a cycle | Males - Equilibriumone
38
FSH receptors
on Sertoli cells | convert testosterone into oestrogen via activation of Aromatase
39
No FSH?
sertoli cells die
40
No LH?
sertoli cells would not be able to maintain and regulate spermatogenesis
41
How are secondary sexual characteristics produced?
Androgens bind to "Androgen Binding Proteins" which get transported via circulation
42
Why do body builders who use steroids usually have low sperm count?
Steriods = include testosterone Exogenous steroids = work on HPG-Axis to down regulate due to negative feedback. Reduces LH/FSH release from pituitary leading to testicular atrophy = decreased sperm production
43
What is the corpus cavernosum?
Spongy tissue which is highly vascular.
44
What happens during an erection?
Blood flow to penis increases from dilation | Venous return restricted so penis is bloated
45
Which ANS component controls the erection?
Parasympathetic system - Point
46
Which ANS component controls movement of sperm in the epididymis, vas deferens and penile urethra?
(Emission) | Sympathetic system - Shoot
47
Which nervous component controls the expulsion of glandular secretions and evacuation of urethra?
(Ejaculation) | Somatic NS - Perineal branch of the pudendal nerve S2-S4
48
Which portion of the ejaculate is sperm rich?
The initial portion
49
Seminal fluid consists of secretions from:
1. Seminal vesicles 2. Prostate 3. Bulbo-urethral gland 4. Epididymal fluid
50
bulbo-urethral gland
produces pre-ejaculate: clear, viscous secretion high in salt
51
pre-ejaculate
1. Lubricate urethra for spermatozoa to pass through at a high speed without damaging them 2. Neutralise traces of acidic urine + getting rid of bacteria
52
What is seminal vesicle fluid made up of?
1. Proteins 2. Enzymes 3. Fructose 4. Mucus 5. Vit C 6. prostaglandins
53
What is the significance of fructose?
It is the energy source for sperm movement
54
What is the significance of prostaglandins?
It increases pH to help protect against acidic pH of vagina.
55
What does the prostate secrete?
A milky or white fluid
56
What is the prostatic fluid made up of?
<1% protein content: 1. Including preoteolytoc enzymes 2. Prostatic acid 3. Phosphatase 4. Prostate specific antigens which are involved in liquefaction 5. High concentrations of Zinc
57
Why jelly-like ejaculate?
cascade - allows it to enter a single area + not leak out
58
What allows the sperm to get through the zona pellucida?
Has sac of acrosome at the tip - proteolytic enzymes which digest outer layer of egg
59
mitochondrial sheath
Machinery for energy production - fructose breakdown
60
Female equivalent of bulbo-urethral gland?
Bartholin's
61
What is the significance of high zinc?
antibacterial