1 - Anatomy Flashcards

1
Q

What are the borders of the breasts?

A

Run from lateral border of sternum to mid axillary line

Lays between 2nd and 6th costal cartilage

Made up of circular body and axillary tail

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2
Q

What happens to the areolae during pregnancy?

A

Enlarge and secrete substance from sebaceous glands that act as a lubricant

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3
Q

What tissues make up the breast?

A
  • Mammary Glands (modified sweat glands)
  • Connective Tissue Stroma (fibrous and fatty)
  • Pectoral Fascia (attachment point for suspensory ligaments onto pec major)
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4
Q

What is the retromammary space?

A

Layer of loose connective tissue between the breast and pectoral fascia

Potential space, often used in reconstructive plastic surgery

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5
Q

What is the arterial, lymphatic and nerve supply to the breast?

A

Arterial

Medial: internal thoracic artery (a.k.a internal mammary from subclavian)

Lateral: see image

Lymphatics

  • Axillary
  • Parasternal
  • Posterior intercostal

Nerve

  • Anterior and lateral cutaneous branches of the 4th to 6th intercostal nerves
  • Milk supply by pituitary gland hormones
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6
Q

What structures make up the vulva?

A
  • Mons pubis
  • Labia minora
  • Labia majora
  • Clitoris
  • Vestibule
  • Bartholin’s glands
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7
Q

What is the vascular, lymphatic and nerve supply to the vulva?

A

Arterial: Internal and External Pudendal arteries

Lymphatics: superficial inguinal

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8
Q

What structures surround the vagina?

A
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9
Q

What is the role of the posterior fornix?

A

Reservoir for semen after ejaculation.

Semen retained in the fornix liquefies in the next 20-30 mins, allowing for easier permeation through the cervical canal.

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10
Q

What are the four histological layers of the vagina from most inner to most outer?

A
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11
Q

What is the blood, lymphatic and nerve supply to the vagina?

A

Blood: uterine and vaginal arteries from internal iliac

Lymphatics :

  • Superior – drains to external iliac nodes
  • Middle – drains to internal iliac nodes
  • Inferior – drains to superficial inguinal lymph nodes

Nerve: Most from autonomic nervous system via uterovaginal nerve plexus. Only inferior 1/5th somatically innervated by deep perineal nerve (branch of pudendal)

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12
Q

What are the three main types of vaginal fistulae and what is the main reason they occur?

A

It typically occurs as a result of prolonged labour (where a Caesarean section is not available). As the fetus slowly progresses down the vaginal wall, it exerts pressure – obstructing the blood supply and causing tissue necrosis.

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13
Q

What is the difference between the ectocervix and the endocervix?

A

Ecto: stratified squamous non-keratinized epithelium

Endo: mucus-secreting simple columnar epithelium.

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14
Q

What is the function of the cervix?

A
  • Passage of sperm
  • Maintain sterility of upper reproductive tract
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15
Q

What is the vascular and lymphatic supply to the uterus?

A
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16
Q

What are the different parts of the uterus?

A
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17
Q

What is the typical anatomical position of the uterus?

A
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18
Q

What are some common abnormal positions of the uterus?

A
  • Excessively Anteflexed
  • Anteflexed and Retroverted
  • Retroflexed and Retroverted
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19
Q

What are the tissue layers of the uterus?

A
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20
Q

What are the different ligaments that give support to the female reproductive system?

A
  • Broad Ligament: double layer of peritoneum attaching the sides of the uterus to the pelvis. Mesentery for the uterus
  • Round Ligament: Remnant of gubernaculum from the uterine horns to the labia majora via the inguinal canal. It functions to maintain the anteverted position of the uterus.
  • Ovarian Ligament: Joins ovaries to uterus
  • Cardinal Ligament: At base of broad ligament from cervix to lateral pelvic walls. It contains the uterine artery and vein
  • Uterosacral Ligament: From cervix to sacrum
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21
Q

How do the fallopian tubes fulfil their function?

A
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22
Q

What are the different parts of the fallopian tube?

A
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23
Q

What is the vascular and lymphatic supply to the ovaries?

A

Lymphatic drainage to para-aortic nodes

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24
Q

What is the pathophysiology of a bicornuate uterus?

A

Paramesonephric Ducts did not fuse properly

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25
Q

What is the process of oogenesis?

A

Begins in fetus before birth

  • Primordial germ cells (from yolk sac of the embryo) move to colonise the cortex of the primordial gonad. Replication by mitosis peaks around 20 weeks. Cell death occurs after this peak to leave 2 million cells
  • Meiosis I before birth and forms primary oocytes
  • Primary oocytes in the gonads as clusters, epithelial cells surrounding them, called the primary follicle.
  • During childhood, further atresia occurs, leaving ~40,000 eggs at puberty.
  • Once puberty begins, a number of primary oocytes (15-20) begin to mature each month, although only one of these reaches full maturation to become an oocyte. Preantral, antral, ovulatory
  • The secondary oocyte will only complete meiosis II following fertilisation.
26
Q

How does the primary oocyte mature?

A

Pre Antral

  • Squamous cells become stratified cuboidal (granulosa cells) and secrete zone pellucida

Antral

  • Fluid filled spaces form between granulosa cells, these eventually combine together to form a central fluid filled space called the antrum
  • This is now a secondary follicle and only one dominates and matures a month

Pre-Ovulatory

  • LH surge induces this stage and meiosis I is now complete. Inside the follicle one polar body and one secondary oocyte. Meiosis II starts, two polar bodies but the secondary oocyte arrests in metaphase of meiosis II. This happens 3 hours prior to ovulation.

Ovulatory

  • Now a Graafian follicle
  • LH surge occurs increases collagenase activity, weakening the follicular wall and ovulation

Fertilisation

  • The secondary oocyte will only complete meiosis II following fertilisation
  • If fertilisation doesn’t occurs, oocyte degenerates 24 hours after ovulation, remaining arrested in meiosis II
27
Q

What needs to happen to sperm after coitus before fertilisation can occur?

A

Capacitation

Reorganises sperm cell membrane and results in the tail movement changing from a beat-like action to a thrashing whip-like action to help propel the sperm forward.

Removal of the protein coat of sperm exposes acrosome enzymes so can penetrate zone pellucida

28
Q

How is polyspermy prevented?

A

Calcium enters the oocyte and the sperm cell stop moving. Rise in intracellular calcium

  • The egg cell membrane depolarises in order to prevent polyspermy – this is the primary block.
  • The cortical reaction occurs, which is where cortical granules that lie just beneath the egg cell membrane fuse with the membrane and release their contents into the zona pellucida. This is a secondary block to polyspermy as it hardens the zona.
29
Q

What are some changes to the endocrine system during pregnancy and why?

A
  • Levels of progesterone (from corpus lute and then placenta) and oestrogen (from placenta) increase
  • Increase in oestrogen levels results in increase in hepatic production of thyroid-binding globulin (TBG). As a result, more free T3 and T4 bind to the TBG, this causes more TSH to be produced. Free T3 and T4 levels remain unchanged – but total T3 and T4 levels rise. Ensures that there is a constant supply of thyroxin to the foetus early in pregnancy as fetes cannot produce it’s own until second trimester
  • Increase in human placental lactogen, prolactin and cortisol levels. These are anti-insulin hormones therefore, they increase insulin resistance in the mother and reduce peripheral uptake of glucose. This ensures that there is a continuous supply of glucose for the foetus.
  • The mother switches to an alternative source of energy which is provided by lipids. The breakdown of lipids can result in ketogenesis thus, pregnancy is associated with an increased risk of ketoacidosis.
30
Q

What are some changes to the cardiovascular system during pregnancy and why?

A

Progesterone decreases systemic vascular resistance in pregnancy which leads to a decrease in diastolic blood pressure during the first and second trimester of pregnancy.

In response cardiac output increases by about 30-50%.

Pregnancy results in the activation of the RAAS leading to an increase in sodium levels and water retention. This means that the total blood volume increases.

31
Q

What are some changes to the respiratory system during pregnancy and why?

A
  • Growth of the foetus causes upward displacement of the diaphragm but does not decrease total lung capacity as increase in the transverse and anterior-posterior diameters of the thorax
  • In pregnancy, a woman faces an increase in their metabolic rate, which leads to an increased demand for oxygen. The tidal volume and the minute ventilation rate increases to help the mother meet these oxygen demands.
  • Hyperventilation due to increased carbon dioxide production and the increased respiratory drive caused by progesterone. Results in a respiratory alkalosis with a compensated increase in renal bicarbonate excretion
32
Q

What are some changes to the gastrointestinal system during pregnancy and why?

A
  • Reflux, nausea and vomiting due to upward displacement of stomach causing increased gastric pressure
  • Appendix may move to right upper quadrant
  • Constipation due to increase in progesterone causing smooth muscle relaxation, which decreases gut motility
  • Risk of gall stones as increased progesterone causes relaxation of gallbladder so biliary tract stasis
33
Q

What are some changes to the urinary system during pregnancy and why?

A
  • Increased GFR by about 50-60% due to increased cardiac output which causes increase in renal plasma flow. Levels of urea and creatinine will be lower as increased clearance
  • Risk of UTIs (usually pyelonephritis) due to stasis from relaxation of the ureter and muscles of the bladder due to progesterone
34
Q

What are some haematological changes during pregnancy?

A
  • Risk of VTE as increase in fibrinogen and clotting factors in the blood and a decrease in fibrinolysis. Additionally, due to an increase in progesterone levels stasis of blood occurs.

Warfarin can not be given to counteract this as can cross the placenta is a teratogen. Use LMWH if needed

  • Dilutional anaemia as plasma volume increases significantly but red cell mass does not increase by as much
35
Q

What happens to the mammary glands during pregnancy?

A
  • Hypertrophy of the ductular-lobular-alveolar system
  • From mid-gestation alveolar cells differentiate to be capable of milk production but little milk secretion due to the high progesterone:oestrogen ratio which favours growth rather than secretion. Only once placenta is delivered and progesterone falls does it start to form milk
36
Q

What is colostrum?

A

First milk produced after birth (24-48 hours after birth)

Contains less water soluble vitamins, fat and sugar than mature milk, but contains more proteins (particularly immunoglobulins) and fat soluble vitamins

40 ml/day

37
Q

What is the let down reflex?

A

Babies do not suck the milk out it is ejected by the let-down reflex

In response to suckling, oxytocin is released from pituitary gland which stimulates myoepithelial cells that surround alveoli to contract thus squeezing milk out of the breast.

Despite suckling being the major stimulus for milk let down, the reflex can be conditioned. The cry or sight of an infant and preparation of the breast for nursing may cause let-down, whereas pain, embarrassment or alcohol may inhibit it.

38
Q

How is milk production maintained and ceased?

A

Maintained: Adequate suckling at a feed to stimulate prolactin for next feed

Cease: Stop suckling, Steroids or Dopamine Agonists. Turgor induced damage to secretory cells and low prolactin levels.

39
Q

How do the gonads develop during embryological development?

A
  • Begin as genital ridges from intermediate mesoderm and overlying epithelium.
  • Germ cells migrate in week 4-6 from yolk sac to ridges
  • Simultaneously, epithelium of genital ridges proliferates and penetrates the intermediate mesoderm to form the primitive sex cords. Germ cell + Sex cords = Gonads
40
Q

How does the internal genitalia form during embryological development?

A

Male

Testosterone (produced by the Leydig cells), causes mesonephric ducts develop to form the primary male genital ducts. They give rise to the efferent ductules, epididymis, vas deferens and seminal vesicles.

Paramesonephric ducts degenerate due to anti-Mullerian hormone – produced by sertoli cells in the testes

Female

Mesonephric ducts degenerate due to lack of testosterone.

Absence of anti-Mullerian hormone allows for development of the paramesonephric ducts

  • Cranial – becomes the Fallopian tubes
  • Horizontal – becomes the Fallopian tubes
  • Caudal – fuses to form the uterus, cervix and upper 1/3 of the vagina.

The lower 2/3 of the vagina is formed by sinovaginal bulbs (derived from the pelvic part of the urogenital sinus).

41
Q

How do the external genitalia form during embryological development?

A

Cloacal folds form genital tubercle, urethral folds and anal folds

Male

  • Presence of DHT causes elongation of tubercle, closure of genital swellings to form scrotum, closure of urethral folds
  • Can get hypospadias from this

Female

  • Oestrogens cause genital swellings to be labia majora and urethral folds to be labia minora
  • Genital tubercle becomes clitoris
  • Urogenital groove therefore remains open, forming the vestibule into which the urethra and vagina open
42
Q

How do the gonads descent?

A

Arise in the upper lumbar region, tethered to the scrotum or labia by the gubernaculum

43
Q

What is the embryologial origin of each part of the vagina?

A
44
Q

What age does puberty take place and what hormonal changes happen?

A

Females: 8-14

Males: 10-16

Hypothalamic-Pituitary-Gonadal (HPG) axis

  • Hypothalamus release GnRH in pulsatile fashion to stimulate anterior pituitary to release LH and FSH
  • LH and FSH stimulate sex hormones to be produced that then negatively feedback
45
Q

What are the stages of puberty in females in chronological order?

A

COME BACK TO AND FINISH

46
Q

Why do males not develop a uterus?

A

They produce anti-mullerian hormone so mullein duct degenerates

47
Q

What are some complications with a heart shaped (bicornuate) uterus?

A
  • Miscarriage
  • Premature birth
  • Malpresentation
48
Q

How may an imperforate hymen present and what is the management?

A

Discovered at menses, patient has cyclical pain/cramping but no bleeding

Retrograde menstruation can lead to endometriosis

Need to do surgical incision

49
Q

What is a transverse vaginal septa, how may it present and how is it diagnosed?

A

Septum transverse across vagina that can be perforate or imperforate

If perforate will menstruate but issues with tampon use and intercourse. If imperforate then similar to imperforate hymen

Dx: MRI, US or exam

50
Q

What are the complications with transverse vaginal septa?

A
  • Infertility
  • Pregnancy complications

Can have surgery to correct but risk of recurrence and vaginal stenosis

51
Q

Why does vaginal agenesis and hypoplasia occur?

A

Failure of Mullerian Ducts to develop

Pt will still have ovaries so will still produce female sex hormones

Use vaginal dilator or surgery

52
Q

What is the pathophysiology of androgen insensitivity syndrome?

A

X linked recessive inheritance in androgen receptor gene. Pt is XY, genetically male with internal testes but female external genitalia

Lack of androgen receptors so body cannot respond to androgen. Androgens get converted to oestrogens so female secondary sex characteristics

Pt has testes and a vagina but no upper vagina, fallopian tubes, uterus, ovaries as testes produce anti-mullerian hormone so they degenerate

53
Q

How may someone with complete androgen insensitivity syndrome present?

A

In infancy with inguinal hernias from testes or in teenage years with primary amenorrhea

  • Lack of pubic hair
  • Lack of axilla hair
  • Lean muscles
  • Taller than female average
  • Infertile
54
Q

What are people with androgen insensitivity syndrome at risk of?

A

TESTICULAR CANCER

55
Q

How may partial androgen insensitivity syndrome present?

A
  • micropenis
  • clitoromegaly
  • bifid scrotum
  • hypospadias
  • diminished male characteristics
56
Q

What will hormone tests show in someone with androgen insensitivity syndrome?

A
  • Raised LH
  • Normal or raised FSH
  • Normal or raised testosterone levels (for a male)
  • Raised oestrogen levels (for a male)
57
Q

How is androgen insensitivity syndrome managed?

A
  • Bilateral orchidectomy to avoid testicular tumours
  • Oestrogen therapy
  • Vaginal dilators or vaginal surgery can be used to create an adequate vaginal length
  • Psychological support
58
Q

How long after delivery does it take the uterus to go back to normal size?

A

4 weeks

(can feel pregnant uterus above pubic symphis at about 12 weeks)

59
Q
A
60
Q
A

POP!!!

Can only fit coil 48 hours after delivery or 4 weeks after