Anatomy Flashcards
(243 cards)
1
Q
What is the pelvis?
A
Space bound by pelvic girdle
2
Q
What is the great pelvis?
A
Upper abdo region of pelvic girdle, above pelvic inlet
3
Q
What is the lesser pelvis?
A
Lower region of pelvic girdle, below pelvic inlet
Pelvic cavity and perineum
4
Q
What is the pelvic cavity?
A
Region between inlet and pelvic floor
5
Q
What is the perineum?
A
Region below the pelvic floor
6
Q
What are differences between the male and female pelvis?
A
Female pelvic girdle is wider, thinner boned and has an approximately cylindrical cavity
Pubic arch in female is wider
7
Q
What term describes the normal desirable shape of the pelvis?
A
Gynecoid
8
Q
What term describes a female pelvis which is shaped more like a males?
A
Android
9
Q
What is an anthropoid pelvis?
A
Anterior posterior distance much greater than the transverse
10
Q
What is a platypelloid pelvis linked with?
A
Rickets
11
Q
What measurements can be taken to determine whether a birth canal is the correct dimensions to permit birth?
A
Diagonal conjugate = (>12 cm) measured by vaginal exam
True Conjugate = (Diagonal conjugate – Pubic symphysis depth =10.5-11.0cm)
Intertuberous distance = (>12cm)
Interspinous distance = (>11cm)
12
Q
Describe the plane of pelvic orientation
A
~60º
ASIS aligns with PT in vertical plane
13
Q
Which direction do the urogenital and anal triangles face?
A
Anal triangle faces postero-inferiorly
Urogenital triangle faces inferiorly
14
Q
What does the perineum contain?
A
External genitalia and distal anal canal
15
Q
What are the female parts of external genitalia?
A
Labia (Majora & Minora)
Crura of clitoris
Bulb of vestibule
Greater vestibular gland
16
Q
What are the male parts of the external genitalia?
A
Crura & bulb of penis Urethra Testes (hanging from abdo wall) Scrotum Bulbourethral gland
17
Q
What neurovascular structures do both male and female perineum contain?
A
Internal pudendal artery (& branches)
Pudendal nerve (& branches)
Perineal membrane
18
Q
What is the pelvic floor?
A
Bowl-shaped group of sheet-like muscles that support pelvic viscera & assist with sphincters
19
Q
What muscles make up the Levator Ani?
A
Iliococcygeus
Pubococcygeus
Puborectalis
20
Q
What is the function of Puborectalis?
A
Maintains angle at anorectal junction to help in faecal continence
Loss of angle leads to increased risk of faecal incontinence
21
Q
What is the Perineal body?
A
Only point of union between pelvic floor and perineal membrane
Important for integrity of pelvic floor
Support to posterior vaginal wall
Attachment point for anal sphincter
22
Q
What is the nerve supply to levator ani?
A
S4
23
Q
What are the borders of the Urogenital Triangle?
A
Ischial tuberosities to pubic symphysis
24
Q
What are the borders of the anal triangle?
A
Ischial tuberosities to coccyx
25
What are female external genitalia?
Folds of skin guarding the vagina and clitoris
26
Where do the greater vestibular glands lie in the female? And what do they do?
Drain into vestibule at 5 & 7o’clock
| Secrete lubricant
27
What is an Episiotomy?
Create a controlled increase in aperture size during childbirth to give a controlled tear
28
What types of incision can be used for an episiotomy?
Midline incision
| Media lateral incision
29
What is the clitoris?
Erectile body very similar in structure to the penis
30
What is the male equivalent to the bulb of vestibule?
Corpus spongiosum of penis
31
What are the female equivalents to the bulbourethral glands?
Greater vestibular glands
32
What is the sensory innervation of the glans of the clitoris and penis?
Pudendal nerve S2-4
33
What does the Female reproductive tract connect the outside world to?
The peritoneal cavity
34
What are the 3 parts of the uterine tubes?
Infundibulum
Ampulla
Isthmus
35
What is the cervical canal?
Connects vagina and uterine cavity via the external and internal os
36
What can be used to directly view the uterine cavity?
Hysteroscopy
37
What can be used to determine whether there is a blockage in the uterine tubes?
Hysterosalpingogram - dye into cavity
38
What presents a route of infection spread by an STI?
Uterine tubes can allow spread from vagina
39
What is an ectopic pregnancy?
Blastocyst implantation can occur into most tissues and development will continue if a placenta is established
40
How might a tubal ectopic present?
6-8 weeks, pain
| Rupture of tube can lead to peritonitis
41
What is normal nulliparous size for a uterus?
Approx 80x50x30mm HxWxD
42
What is the pelvic girdle?
Bony pelvis
43
What tool can be used to view the cervix?
Speculum
44
What are the fornices?
Superior portions of vagina extending into recess created by vaginal portion of the cervix
45
What tissue type are the ovaries derived from?
Intermediate mesoderm
46
What is the blood supply to the ovary?
Ovarian artery
| Branch of the aorta at L2
47
Where do the ovaries sit? And what are they suspended in?
Sit close to lateral pelvic wall suspended in broad ligament
48
What is the ovary covered in? And what goes through this layer?
Covered in peritoneum which forms surface epithelium (germinal layer) covering
Ovulation takes place through this layer and into peritoneal cavity
49
What is the round ligament of the ovary similar to in males?
Gubernaculum
50
What could Ovulation/cysts/tumour impinge on?
Obturator nerve (L2-4)
Resulting in pain/ache in medial thigh, hip or knee; medial thigh
weakness/wasting
51
What is the blood supply to the uterus and vagina? And where do they pass?
Uterine: branch of internal iliac, Heads toward lateral cervix and fornix, Passes superior to ureter
Ovarian: From aorta at L2
Vaginal: Often a branch of the uterine, Can arise independently from internal iliac
52
Where does the ureter pass in relation to the uterine artery? And what is the significance of this?
Passes inferior to uterine artery (water under bridge)
| Very delicate and must not be ligated, crushed or moved too much
53
Why can cervical cancer cause kidney failure?
Compression/obstruction of ureters as they run in close proximity to cervix
54
Where do Uterine & cervical lymphatics drain?
Pass to external, internal iliac & sacral nodes
| Some go to palpable inguinal nodes via round ligament
55
What is a hysterectomy?
Removal of uterine body alone – cervix preserved
56
What is a Bilateral salpingo- oophorectomy?
Removal of tubes & ovaries
57
What is a radical hysterectomy?
Removal of everything including lymphactics
| Distal vagina normally preserved
58
What is a normal position of a uterus and what supports it?
Anteverted anteflexed
| Rests on bladder and is supported by it in this position
59
What is the angle of anteversion?
Between vagina and cervical canal
60
What is the angle of anteflexion?
Between cervical canal and uterus
61
Which position of the uterus carries the highest risk of prolapse?
Retroverted retroflexed
62
How can you estimate the size and position of the uterus?
Bimanual palpation
| Vaginal exam with other hand on abdomen
63
What is the round ligament of the uterus?
Equivalent to male gubernaculum
| Route for uterine lymphatic drainage to superficial inguinal nodes (palpable)
64
What does peritoneum cover in the pelvic region of a female?
Bladder, uterus, cervix and upper rectum
65
What is the folded peritoneum region between bladder and uterus called?
Vesico uterine pouch
66
What is the folded peritoneum pouch between the uterus and the rectum called? And what clinical significance does it have?
Recto uterine pouch (pouch of Douglas)
Relevant to infected fluid accumulation
Abscess & fistula formation
Home abortion – line of travel of inserted implements
67
What is the broad ligament?
Large double layered fold of peritoneum
68
What are the different parts of the round ligament?
Mesovarium
Mesosalpinx
Mesometrium
69
Where does the round ligament travel?
Passes through Inguinal canal and into labia majora
70
Where does ovulation take place?
Ovulation takes places through peritoneal covering
| Germinal epithelium
71
What are the layers of pelvic fascia?
Visceral (covers organs)
Parietal (covers muscles & walls)
Endopelvic: Loose & fatty (fills spaces), Dense & fibrous (supportive ligaments)
72
What comes together at the tendinous arch?
Dense pelvic fascia
73
What ligament supports the cervix/uterus?
Cardinal ligament
74
What ligament supports the bladder?
Lateral ligament of the bladder
75
What ligament supports the rectum?
Lateral ligament of the rectum
76
Where does the tendinous arch run?
From pubis to sacrum
77
What is the Paracolpium?
Connection of vaginal fascia to tendinous arch
| Important for support
78
What do uterine tubes develop from?
Paired paramesonephric ducts
79
What can Uterine & vaginal malformations lead to?
1° amenorrhoea, infertility or problematic pregnancy
80
Visceral sensory fibres from the uterus travel to the CNS via two different routes. What are they?
Pelvic organs above pelvic pain line covered in peritoneum Refer pain to T10-L1 (via Sympathetic nerves)
Pelvic organs not covered in peritoneum below pelvic pain line Refer pain to S2-4 (via Parasympathetic nerves)
81
Describe uterine innervation
Sensory Neurons above pelvic pain line run with Sympathetics (T10-T12)
Sensory Neurons below pelvic pain line run with Parasympathetics (S2-4)
Somatic sensory innervation to distal vagina (S2-4 Pudendal nerve)
82
How would you anaesthetise the uterus above the pelvic pain line?
Spinal Block @ L3/4 (inject into CSF)
& an epidural at the same level
(Combined spinal epidural – CES/CSE)
83
How would you anaesthetise the uterus below the pelvic pain line?
Caudal epidural (sacral hiatus & canal)
84
How would you anaesthetise the distal vagina?
Pudendal Nerve Block
| Palpate ischial spine and inject around it via vaginal wall
85
What structures will be anaesthetised by a pudendal nerve block?
Perineum, distal vagina & anal canal
86
What is the testicle a derivative of?
Intermediate mesoderm
87
Where does the testicle lymph drainage go to?
Para-aortic nodes ~L2
88
What structure aids the descent of the testicle through the inguinal canal?
Gubernaculum
89
What is the path of sperm from their site of production?
```
Produced in seminiferous tubules
Into Rete testis
Head of epididymis
Body
Tail
Ductus deferens
```
90
What is a hydrocele?
Excess fluid in tunica vaginalis
91
What is a spermatocoele?
Swelling of epididymis
92
What is the Processus vaginalis?
Fold of parietal peritoneum
| Future site of inguinal canal
93
What forms a potential weak spot and is the route taken by indirect inguinal hernias?
Processus vaginalis
94
Which layer of the abdo wall doesn't contribute to the spermatic coverings?
Transversus abdominis
95
What forms the tunica vaginalis?
Lower part of processus vaginalis
96
Describe the Content of the spermatic cord
1. Pampiniform plexus
2. Ductus deferens
3. Lymphatics
1. Testicular artery
2. Ductus deferens artery
3. Cremasteric artery
1. Genital nerve
2. Autonomic nerves
3. (Ilioinguinal nerve)
97
Describe the coverings of the spermatic cord
```
Internal spermatic fascia
Cremasteric fascia
External spermatic fascia
Colles fascia
Dartos fascia
Skin
```
98
What are the origins of the internal and external spermatic and Cremasteric fascia layers?
Internal spermatic fascia: transversalis fascia
Cremasteric fascia: internal oblique
External spermatic fascia: external oblique
99
What is the function of the pampiniform plexus?
Countercurrent heat transfer mechanism as it wraps around the arteries entering the cord
100
If someone presents with a left sided varicocele what should be checked beyond the testicles?
Left kidney due to direct drainage route of testicular veins
Right kidney drains straight into IVC
101
Which nerve is at risk during a vasectomy?
Ilioinguinal
102
What is the ductus deferens?
Smooth muscule tube capable of peristaltic action via sympathetic innervation
Derived from embryonic mesonephric duct
Runs from tail of epididymis to ejaculatory duct
103
Where does the ductus deferens run in relation to the ureter?
Superior to ureter in the pelvis
| Only structure to do so and can be seen on abdominal endoscopy
104
Where does the ductus deferens get its blood supply?
Branches from vesical & testicular arteries
105
What is Male Sterilisation (Vas-ectomy)?
The ductus is cut & ligated just distal to superficial inguinal ring
106
Describe the structure of the prostate
Fibromuscular (1/3) & glandular (2/3)
107
Where is the blood supply to the prostate from?
Internal iliac artery (vesical & rectal arteries)
108
Where is the venous and lymph drainage from the prostate?
Venous blood to prostatic venous plexus then to vertebral veins
Lymph to internal iliac nodes
109
What is the visual landmark for the prostate in the urethra?
Urethral crest
110
What are the three openings into the prostate in the urethra?
Utricle - blind ended pouch
| 2 Ejaculatory ducts
111
What are anatomical relations of the prostate?
Bladder
Levator ani
Rectum
Pubic symphysis
112
Where can prostate cancer spread?
Vertebrae via venous plexus
| Valveless veins form the plexus which runs length of vertebral column into cranium & through vertebral bodies
113
What are the lobes of the prostate and what are they described in relation to?
Anterior, posterior and median
| Based on the positional relationship of prostate to urethra & ejaculatory duct
114
What are the zones of the prostate?
Peripheral (PZ)
Central (CZ)
Transitional (TZ)
115
What is the function of the seminal vesicles?
Produce alkaline fluid
| Sperm can hang around in here for a few days
116
How do the seminal vesicles develop?
Outgrowth of ductus deferens
| Join ductus deferens to form ejaculatory duct
117
What is the blood supply, venous drainage and lymph drainage of the seminal vesicles?
Internal iliac artery (Inferior vesical & middle rectal)
Vesical & prostatic venous plexus
Lymph Drainage: Internal iliac nodes, External iliac nodes, Sacral nodes
118
What is the posterior relation of the seminal vesicle?
Recto vesical pouch
119
What should you normally be able to feel on a digital rectal examination?
Walls of anal canal
Walls of inferior rectum
Sacrum, coccyx & sacral lymph nodes
Prostate (Post. & med. lobes and median sulcus)
Possibly Inferior bladder & seminal vesicles
120
What forms an anchor point for the external genitalia?
Perineal membrane
121
What are the different parts of the male urethra called from the bladder?
```
Preprostatic
Prostatic
Membranous
Spongy
Navicular fossa
```
122
What is the most likely consequence of an enlargement of the prostate?
Compression of the urethra
123
Why do a male catheterisation?
Inability to void bladder (urinary retention)
Incapacitated
Surgery
124
What are difficulties and dangers of male catheterisation?
Navicular fossa (mucosal fold superiorly)
Angle at penile bulb & membranous urethra
Prostate (crest / enlarged lobes)
Sphincters
125
What can blunt force trauma to the penile bulb cause?
Rupture of urethra resulting in extravasation of urine
126
What are symptoms of bulbourethral gland stones or infection?
Perineal pain and pain on defecation / digital rectal examination
127
What type of innervation controls muscles in the deep perineal pouch?
Voluntary muscles (pudendal nerve (S2-4))
128
What structures are found in the male deep pouch?
External urethral sphincter
| Bulbourethral glands
129
What structures are found in the female deep pouch?
External urethral sphincter
Sphincter urovaginalis
Compressor urethrae
Vaginal canal
130
What do the crura of the penis/clitoris attach to?
Pubic arch & lateral parts of the perineal membrane
131
What does the Superficial perineal pouch contain?
Penis, urethra, scrotal contents & superficial perineal muscles
132
If fluid leaked into the superficial pouch, where could it go?
Could spread to penis, urethra, scrotal contents, superficial perineal muscles and up abdo wall as the fascia is continuous with scarpers and campers fascia
133
What is epispadias?
Urethral opening on dorsum of penis
134
What is hypospadias?
Urethral opening on ventrum of penis
135
Describe the structure of the corpus cavernosum
Open vascular structure
136
What can be cut to give the penis a greater flaccid length?
Suspensory & Fundiform ligaments of the penis
137
What is priapism?
Persistent (painful) non-stimulated erection that lasts more than 4 hours
138
What is Phimosis?
Prepuce (Foreskin) can not be retracted
139
What is Paraphimosis?
Prepuce (Foreskin) stuck in retracted position
140
When could Paraphimosis occur?
Can occur post coitally if foreskin hasnt been put back into position
141
How does the neurovascular supply to the penis get there?
Inferior to pelvic floor via deep perineal pouch and through pudendal (Alcock) canal
142
Where does Somatic nerve supply to the penis come from?
Dorsal nerve of the penis (from Pudendal nerve)
143
Where can the pudendal nerve be anaesthetised?
Close to the ischial spines
144
Describe the blood supply to the penis
Internal pudendal artery (from internal iliac)
| Deep & dorsal penile arteries (for erection)
145
Describe the venous drainage of the penis?
```
Dorsal Veins (superficial & deep)
Drain to prostatic venous plexus
Blood drains to vertebral plexus
```
146
Which branch of nervous system is responsible for erection, secretion and ejaculation?
Erection: Point, Parasympathetic
Emission: Shoot, Sympathetic
Ejaculation: Score, Somatic
147
What process occurs to cause erection?
Straightening of coiled helicine arteries by smooth muscle relaxation which allows blood to fill the corpus cavernosum
Bulbospongiosus & ischiocavernosus muscles compress venous plexus (retain blood in penis)
148
What allows the penis to be flaccid in its resting state?
Arterio-venous anastamoses allows blood to bypass the corpus cavernosum
149
Describe the parasympathetic nerve supply from the spine to the penis
Pelvic Splanchnic Nerves
Inferior hypogastric plexus
Prostatic plexus
Cavernous nerve
150
What could result in cavernous nerve damage and therefore cause impotence?
Prostatectomy due to prostatic plexus disruption
151
Where is the inferior hypogastric plexus located?
Lateral pelvic wall
152
What effects does sympathetic stimulation have to result in secretion ready for ejaculation?
Closes internal urethral sphincter
Peristalsis of ductus deferens & seminal vesicles
Prostate smooth muscle contraction
Ejaculate squeezed into the penile bulb
153
Which sympathetic nerves bring about Ejaculatory secretion?
L1-2
154
What are the somatic muscles of erection & ejaculation innervated by?
Branches of the pudendal nerve S2-4
155
What are the somatic muscles of erection & ejaculation?
Bulbospongiousus: Covers bulb of penis, Helps urethral emptying, Essential for ejaculation
Ischiospongiousus: Covers crura of penis/clitoris, Helps maintain erection
156
What is the lymph drainage of the Scrotal, penile & perineal skin
Superficial inguinal nodes
157
What is the lymph drainage of the Glans of penis?
Deep inguinal nodes
158
What is the lymph drainage of the Corpus Cavernosum?
Internal Iliac nodes
159
What is the lymph drainage of the urethra?
```
Proximal spongy & membranous (internal iliac)
Distal spongy (deep inguinal)
```
160
What is the lymph drainage of the Prostate, seminal vesicles & ductus?
Mostly internal iliac nodes
161
What factors can affect the shape size and structure of the breast?
```
Age & sexual maturity
Nutrition
Inherited factors
Menstrual cycle
Pregnancy
Lactation
```
162
How many lactiferous ducts does the nipple receive?
15-20
163
What are Montgomery glands?
Sweat & sebaceous glands in areolar of nipple
164
Where might you find supernumerary nipples?
Along mammary ridge/milk line from anterior axillary fold to groin
165
Where does the base of the breast sit?
Over ribs 2-6 and extends from the sternum to midaxillaryline and superolaterally into the axilla
166
What muscles does the breast sit on?
Sits over the fascia of pectoralis major and serratus anterior
167
Where does the breast receive its innervation from?
T4-T6 intercostal nerves
168
What can mastalgia be?
Cyclical
Non-cyclical
Non-breast origin: Cardiac, Respiratory, Musculoskeletal, Infective - shingles
169
What are the quadrants of the breast?
Upper and lower
| Inner and outer
170
What types of tissue are found in the breast?
Connective, glandular and fatty tissue
171
What do cooper Ligaments do?
Support breast tissue - fibrous support
172
Where is the retromammary space?
Between breast tissue and pectoralis fascia
173
What occupies the retromammary space? And what is its function?
Loose connective tissue & fat occupies
Permits free movement of breast independent of pectoralis major
There should be no attachment to underlying muscle
174
What is the blood supply to the breast?
Medial mammary: From internal thoracic/anterior intercostal
| Lateral mammary: From lateral thoracic artery & posterior intercostals
175
Where can breast lymph nodes drain to?
```
Anterior & central axillary nodes
Interpectoral (Rotter) nodes
Parasternal (internal thoracic) nodes
Contralateral parasternal nodes
Contralateral breast
Subdiaphragmatic/hepatic nodes
Inguinal lymph node
```
176
Where do breast skin lymph nodes drain to?
Axillary, deep cervical & infraclavicular nodes
177
Where are infraclavicular lymph nodes?
Sit in the deltopectoral triangle/ infraclavicular fossa
178
What can follow a mastectomy with axillary lymph node clearance?
Upper limb lymphoedema
179
What is a gland?
Collection of epithelia cells that secrete substances
180
What different forms can exocrine glands take?
```
Tubular = straight
Acini = islands connected to duct
```
181
What does Actively lactating breast tissue look like?
clear glandular tissue in an acinar arrangement
182
What visible features may indicate breast cancer?
Nipple retraction
Peau d'orange
Skin tethering
183
Why do a clinical breast examination?
Screening
Monitoring
Presenting problem
184
What is the triple approach in breast examination?
Clinical examination
Imaging: Mammography, Ultrasound
Pathology: Cytology (FNAC fine needle aspiration cytology), Core Biopsy
185
What are patterns of breast metastasis?
Local: skin and muscle
Lymph nodes: axilla
Blood: bone, brain, liver, lung
Trans coelomic: pleura
186
What are steps in examining the breast?
Visual Inspection: symmetry, skin changes
| Palpation: breast tissue, lymph nodes
187
What are landmarks for palpation of the breast?
Midaxillary line
Inframammary ridge-5th/7th rib
Lateral edge sternum
Across clavicle
188
What are special considerations when performing a breast exam?
Timing of exam: when in cycle. Follicular phase after period best time
Large breasts: have her lean forwards
Implants / augmentation: may be scar tissue
Mastectomy
189
Why monitor the foetus in utero?
Monitor growth: Identify IUGR (intrauterinegrowth restriction)
Monitor development: Identify anomalies
Optimise in utero conditions
Prevent / Intervene / Deliver / Be prepared
190
What can be causes for still births?
Unexplained - inter uterine growth restriction 28%
| Major congenital abnormality 9%
191
How can you estimate foetal weight?
Estimated by head circumference, foetal length, abdominal circumference - glycogen stores in liver
192
Describe interuterine growth restriction
Symmetric: Head Circumference & Abdo Circumfernce decreased
Asymmetric: Head Circumference preserved, abdo Circumfernce decreased. Brain sparing
Small for gestational age, Growth under 10th centile
193
What biophysical measures can be take of the foetus in utero?
Heartbeat
Movement, kicking
Foetal breathing (12-14 weeks): diaphragmatic movements
Foetal responses: to sound, amniocentesis, move away from needle
Foetal urine, amniotic fluid volume
194
Describe oxygen delivery to the foetus
Simple diffusion across placenta:
195
What is a congenital abnormality? Give examples of types
```
Abnormalities present at birth
Malformation
Deformation
Dysplasia
Disruption
```
196
What is teratogenesis?
Abnormality induced in a developing organism during uterine life by foreign agents, teratogens
197
What factors can cause teratogenesis?
```
Chemicals/pollutants/radiation
Alcohol
Dietary intake
Viruses
Medication during pregnancy
```
198
What type of teratogenesis does alcohol result in?
Fetal alcohol syndrome
199
What type of teratogenesis does vitamin a lead to?
Cleft palate, mandibular hypoplasia, heart defects
200
What type of teratogenesis does rubella or HSV lead to?
Deafness, cataracts, retinal dysplasia, microcephaly
201
What type of teratogenesis does x ray lead to?
Microcephaly, spina bifida, cleft palate
202
What type of teratogenesis does sodium valproate lead to?
Neural tube defects, facial defects, limbs
203
How might pregnant women be exposed to teratogens?
Drug used prior to knowledge of pregnancy
Drugs necessary for condition independent of pregnancy
Drugs necessary due to pregnancy specific condition
Environmental agents which are impossible to avoid
204
What dietary agents can cause teratogenic problems in pregnancy?
Folate deficiency
Zinc: too low or too high may cause problems
Glucose & ketone bodies: diabetic conditions
Retinoid excess
205
When is the embryo/fetus at risk of damage by teratogens?
Weeks 3-14, when cell division is high, organogenesis is occurring, midline Union is occurring
206
When can neural tube defects be induced by teratogens?
Weeks 3-16
207
When can cardiac abnormalities be caused by teratogens?
Week 3 1/2 to week 6
208
When are upper limbs at risk by teratogens?
Weeks 4+5, micromelia/ Amelia
209
When is there a risk of causing a cleft lip by teratogens?
Weeks 5+6
210
When is there a risk of developing ear problems by teratogens?
Week 4-9
211
When are you at risk of developing a cleft palate by teratogens?
Week 7-9
212
What can influence the teratogenicity of a substance?
Teratogen must contact developing embryo/fetus
Period of development at exposure
Exposure timing & dosage
Foetus genotype influences susceptibility
213
What are Wilsons 6 general principles of teratology?
Final manifestations of abnormal development: death, malformation,
growth retardation and functional disorder
Susceptibility of conceptus: varies with developmental stage at time of exposure
Teratogenic agents act in specific ways on developing cells and tissues in initiating abnormal embryogenesis
Manifestations increase from no-effect to totally lethal level as dosage increases
Access of adverse environmental influences to developing tissues
depends on nature of the agent
Susceptibility depends on genotype of conceptus and on the manner in which genotype interacts with environmental factors
214
How can a substance be teratogenic?
Chromosomal abnormalities leading to changes in DNA
Interference with cell differentiation
Failure of normal cell-to-cell interactions
Failure of normal cell migrations
Interruption of DNA or RNA synthesis
Mutational changes in DNA sequences
215
What are the key features of foetal alcohol syndrome?
Heart defects
Short palpebral fissure
Midline facial abnormalities (maxillary)
Lack of philtrum & thin top lip
Heavy epicanthic folds
Flattened nose
Neural problems - Behavioural & developmental
216
What agents can cause teratogenic limb abnormalities?
Thalidomide (anti-nauseant, sleeping pill)
Retinoids (vitamin A derivatives)
Mechanical via amniotic bands strangle tissue
217
What is Amelia, meromelia and phocomelia?
Amelia - no limb
Meromelia - shortened limb
Phocomelia - seal like limb
218
What is polydactyly and syndactyly?
Poly - extra digits
| Syn - webbed digits
219
What cells can septal defects be associated with?
Neural crest cells
220
What deficiency can lead to neural tube defects?
Folic acid
221
What teratogens can lead to facial defects? And what defects could these cause?
Antiseizure drugs, retinoids, corticosteroids
Cleft palate & lip Cleft lip: abnormal neural crest cell migration
Tongue: macroglossia, microglossia
222
Describe Treacher-Collins or Pierre Robin Syndrome
Autosomal dominant or teratogen-induced (alcohol, retinoids, maternal diabetes)
Mandibulofacial maldevelopment/dysostosis (zygoma, mandible & maxilla)
Downslanting palpebral fissure
Malformed ears & possible conductive deafness
223
What can be done to reduce risk of teratogens exposure in pregnancy?
Advice pre-conception (Nutritional & Lifestyle)
Avoid prescribing where possible
Choose safest and prescribe minimal therapeutic dose
224
What are the 3 tissue sources for the development of the gonad?
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Gonadal Ridge (intermediate mesoderm)
Mesodermal epithelium (posterior abdominal wall)
Primordial Germ Cells (yolk sac)
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225
What type of internal reproductive tract is present at weeks 5-7?
Indifferent genital duct system
226
What happens to the mesonephric and paramesonephric ducts?
Mesonephric duct: Males: testosterone production drives the development of mesonephric duct, Females: Degenerates Paramesonephric duct: Males: antimullerian hormone production causes paramesonephric duct regression, Females: Persist & develops
227
What stimulates mesonephric ducts to form male derivatives?
Testosterone secretion by testis in week 8
228
What does the mesonephric duct form?
Ductus deferens, ejaculatory duct, epididymis & seminal vesicle
229
What results in persistence of paramesonephric duct and degeneration of mesonephric ducts?
Lack of testosterone & anti-mullerian hormone
230
What do the paramesonephric ducts form?
Uterine tubes & join to form uterus & upper vagina
231
How do the paramesonephric ducts form?
Invagination of the coelomic epithelium (future peritoneum)
232
Paramesonephric ducts move to midline and fuse to form uterus. Also pull with them a covering fold of peritoneum, what is this?
Broad ligament
233
What are the names of persistent mesonephric duct remnants called?
Around ovary: epoophoron
| Lateral uterus: Gartner duct
234
Name some types of uterine malformations
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Unicornate uterus
Arcuate uterus
Septate uterus
Bicornate uterus
Didelphic uterus with a septate vagina
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235
What does the urorectal septum do?
Divides cloaca into urogenital sinus & rectum
236
What is the perineal body?
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Remnant of the urorectal sinus
Point of union between pelvic floor and perineal membrane
Important for integrity of pelvic floor
Support to posterior vaginal wall
Attachment point for anal sphincter
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237
What does the vagina develop from?
Uterovaginal canal and sinuvaginal bulb of urogenital sinus
238
What canalises to form the vaginal lumen?
Solid vaginal plate formed from the sinuvaginal bulb
239
What is the hymen?
Sits between vaginal lumen & urogenital sinus
240
What is vaginal atresia?
Vaginal plate fails to canalise
241
What is a transverse vaginal septa?
Failure of canalisation of vaginal plate and/or uterovaginal duct
242
What are male and female homologues of genital development?
Urogenital Fold: Penile urethra, Labia minora
Labioscrotal Swelling: Scrotum, Labia majora
Genital tubercle: Glans penis & erectile tissue, Clitoris
243
What is the midline raphe of the penis?
Point of midline fusion during development
